MEDICAL ELECTRICITY RONTGEN RAYS AND RADIUM WITH A PRACTICAL CHAPTER ON PHOTOTHERAPY BY SINCLAIR TOUSEY, A. M., M. D. CONSULTING SURGKON TO ST. BARTHOLOMEW'S CLINIC. NI-.W YORK. CITY THIRD EDITION, THOROUGHLY REVISED AND GREATLY ENLARGED CONTAINING X fi 1 PRACTICAL ILLUSTRATIONS, 16 IN COLORS W. B. SAUNDERS COMPANY 1921 DEDICATED TO MY FATHER, JOHN EUART TOUSEY. PREFACE TO THE THIRD EDITION MOST important advances have been made in dental and gastro- intestinal radiography and in the standardization of apparatus and technic. The latter has made possible tables showing the correct exposure for radiographs of every portion of both sexes and of every weight and measurement. The saving in time and the certainty of good results have been obtained by many hundred hours' work in studying the methods and results in thousands of radiographs. The rehabilitation of those suffering from the results of war injuries is .mother important subject. Then 1 are described in this book inventions, patented and unpat- ented, and it is not to be assumed because patents are not specifically mentioned in connection with the various descriptions that there are no patents or that the rights are not protected. SINCLAIR TorsKY. \F.\S YOKK CITY, .1 /.", Insulators and Conductors ..... L'.~i The Leyden Jar ............... '_''> Nature of Electric Sparks ............ L'7 The Modern Static or Influence Machines. . :',() Sonic Practical Electric I'nits ........ Is Sources of Hiffli Electromotive Eorce or Static Elect ricitv . . . ">-l The Physical Effects of Static Electricity. . ">."> Met hods of Therapeut ic Application of Static Klectricitv . "/) The Dosage of Static Electricity ..... 70 Physiologic and Therapeutic Effects of Static Electricity ............ 71 DYNAMIC EI.KCTIUCITY .......................... ............... 7S Nature of Dynamic Electricity ............. ........ 7s Sources of Dynamic Elect rcity .............. ......... N2 The Voltaic or C,alv;"i,c Cell ........................ . . S'J Thermo-electricity ...................... ( .i7 Storage Batteries or Accumulators. '.!> The Production of Electricity l>y Electromagnetic Induction Idti The Dynamo .......................... ll'.'l The Induction of Dynamic Electricity by Electric ('mi'eni<. 1^>'_' The Character of the Alternating Elect ric-hirht ('uri'ent liil Detection and Measurement of Electric ('urrent< ..... Itil) Elect roma^netic ( lalvanometers . . 17.'1 The- Measurement of Electromotive |-'orce I'.tl Regulation of Electric ( urrents ...... '_'u| Measui'ements of Resistance ................... Electrolysis ................................... '-Ms The Thermal Effect of the Electric Current 'Jii'J L'HS Us 12 l*Sli PHYSIOLOGIC EFKF.("I\S OK I'j.K.c'nucrrv ............ '-".>- Physiolouic Effects of Electricity upon Microorganisms 'J!'_' Physiologic EtVects upon \'ertelirate Animal- '_' M .i The Effect of Elect ricity upon Anim:d Tissu Muscular ( 'out ract ion Result inii from l'!lect ric Stimulation The Myoiiraph ........................... The Elect rocardiofifaph ..................... Reactions to Electric Stimulation in NYuromiisciilar Preparation ( '( >rt ical St imula I ion ........ St imulalioii of t he < V rebel la r Peduncle< . Electric Stimulation of the Spinal * 'ol'd Rellex Stimulation bv Elecii'icitv . KI.KC i 'in ii)i:s . . . Materials for Electrodes Elect rode.- for Sui face Applicat ion Elect rode- for < ialvaiiopimet lire 11 CO NT K NTS PACE Ki.K.tTKoDi \<;NOSIS 38t Progno-i< Ba-ed on Klect rodiagnosis . ... . ... 397 IONIC M K.DIC \rioN in KI.KCTKOI.YSIS. . 399 K\A.M1'I.KS OK CiAI.VANlC, KAKADIC. A N IP Si N I 'Mil 1) \ I. Kl.lX I KoTH K If \ I' Y 422 1 1 vdro-electric Baths ... 43(1 O/one 44X Pm>l< \I. 111. i O.NSTHl i TIOV AlTKK \\ AH IN.ITHIKS . . . 4A1 I'm --1< il. i H, 1C AND III KKAI'IH Tir KlTKtTS ol Kl.KCTKOM A(iNKTS 4A3 Ki.KrnuriTY IN DI>I:\>F.S OK TIIK Ni-:uvor> SYSTKM 4AA Diagnosis of Disorders of the Peripheral Nervous System. . .... 4AA Disease of the Peripheral Sensory Nerves 470 Diagnosis and Treatment of Disease.- of Peripheral Motor Nerves and Motor Centers . . 470 Klect roinechaiiot herapy 4X3 Practical Kxamples of the I'se of Condensers in Electrotherapeutics. . . 49A In Connection uith the Static Klectric Machine 49A In Connection with Induction-coils A01 Neuralgia and Neuritis A01 Kli'd i icily in Treatment of Organic Diseases of the Central Nervous System All Spinal ( 'ord Al 1 Brain Alti (ieneral Nervous Disorders AH) Neurasthenia A22 Klectric Sleep and Klectric Death A2X Physiologic Causes of Death liy Klectricity A34 I Inai-KKi-x^rKNcv CTHKKNTS A3X The ( Midin Pu-onator . A4X Tesl :t High-frequency Current . . AAO Methods <>f Applying High-frequency Currents . AA2 \acuum Klect rodes \\ith Insulated Stems AAS * M her Applications \\ith Kt'tects Hesemhling Tho-e of High-frequency The Physiologic Kl't'ects of High-frequency Currents A(iX The I'iH'ect- oi ( ieneral Applications of High-l reqiiency ( 'urrents A74 Dial hi-rm\ or Theinioj tenet rat ii in (131 I'HKNoMKNV ACCOMI'ANYINC '1111. Tl{ A NSM IIO.N oK Kl ,K( 'TUK 'I 1 1 TllKotiiH (i \sr.s (142 Imiixatioii of ( iases (142 The Pa --a ne of KlectriciU Through a Vacuum M~> I'HO 10 i ni.it \i"i . tlAA Principles of Phi plot herapy . . (17(1 l-Aample- of the Therapeutic I < of Klecinc Arc Light lixs 'i HI-. / - 1; \ i (W2 Piopi-i i ies of t he ./-Hay (1(14 I he I 'rod i irt ion of t he .c-Ka\ in a ( las-filled Tube, tl()(l I i in i is of I .led I lc ( ieliel al ols Adapted to K\cit Ilig all .1 -IJaV Til lie 7 1 A IJeuulat ion of i he PrimaiA ('urrent 72(1 'I he Type of Tlllie .....'... 7AX iial\ l,'a\- 7(U I'd-- \uf hoi 's '( '..niacl I )iaphrat:m . XO I Tin Si-n-ll|\-eness of the l-'illll. Plate, 0] P:ipel XOX I : . : x2( i 1 .01 ah/atloli of l-'oreign Bodies. XI H DP \ i-|i ipmeiit i if r-l{a\ Pict ii res X70 I lii nd Padiouraph\ of Special Part- \ the Bmlv X(lA Th. Hi H (102 T.-chnic I'm I )ental Padiom-a]hy OMO 'I h,- \i ck )XX CONTKNTS THK .r-llAv: Fluroseopy ;i.iid Radiography of Special Parts of the Body The Chest ... '.I'.Ki .r-Ray Diagnosis of Karly I'liltnoiiary Tuberculosis . Hill Radiography of I lie Thorax in Pneumonia Hll I Bronchieclasis H)|.~> Foreign Bodies in tin- Ijing. Hll.'i The Lung Reflex . lOir, Radioscopy of the Ksophagus. Htltl Radiography of tin- Spine 10ir> The Abdomen and Pelvis 1(117 The Stomach and Intestines 1021 The Author's Technie for (last ro-mtest inal Radiography. . 10^."> rrinary Calculi 104S Hydronephrosis 10(>2 E'yelography KM).". Perinephritis Hlli.'J Hemorrhagic Nephritis Hit):! Renal Tuberculosis 1(1(11 Radiography of Yosical Calculus. 1(101 Prostatie Calculi HHif) Foreign Bodies in the Pelvic Organs. HMK1 The Pelvic Bones 1(1(1(1 The Hip-joint ions The Thigh 1071 Radioscopy of the Knee 1072 Radiography of Bo\v-legs . H)7." Radioscopy of the Leg K>7"i Fluoroscopy and Radiography of the Foot . loso The t'pper Extremity Hixii Radioscopy in Diseases of the Bones and .Joints 110.1 Radiography in Tumors of the Bones and Joints 1 10.") Acromegaly 1 Hiti Bony Changes Shown by Radiographs of Castrated Animals 1107 Osteomyelitis and Necrosis . 1107 Acute or Chronic Periostitis 110X A Cast- of Obscure Disease of the Shoulder. . 1 10X Syphilis of the Bones. 1 1 HI Syphilitic Inflammation of the Bones fNon-gimunalous 111:1 Bone Syphilis in Animals . 1111 Rickets The Joints in Rheumatism 111") The Joints in ( lout .111(1 The Joints in Rheumatoid Arthritis or Rheumatic (lout . 1117 Hypertrophic Arthritis or Ost co-arthritis 1117 Charcot's Joint The Tabetic Joint . . 11 IX (lonorrheal Arthritis. . Tuberculosis of Bones and Joints. Kxamples of the Value of 1 he .r-Ray in the Anatomic Age Determined by Radiology. Detection of Pearls in Oysters '. . . 11-0 Physiologic Effects of the .r-Rays 1 i:',0 From Mild Applications .r-Ray Burns or Rontgen Dermatitis. . . 1112 Precautions Against .r-Hay Injuries. ... 111.) Ri >vn ,i:\i >TM MtAi'Y The Treatment of Disease by the .r-Ray The Technic of Rontgen Therapy The .r-Ray in the Treatment of Malignant Di.-easc .r-Ray Treatment in Particular Diseases Skin Diseases ... .r-Ray Therapy in Tuberculosis . Arthritis Deformans . . . Trachoma Radiotherapy in Syriimomvelia Old Sprains.' '. .' . . .1101 II) ('ONTKNTS PAGE RoNTdKMiTHKKAPv: .c-Ray Treat men I in Particular Diseases Diseased Tonsils 1192 Locomotor Ataxia 1 P>2 .r-Ray Treatment of Facial Neuralgia 1192 ./-Ray Applications Alter Nerve Resection for Tic Douloureux , 119:3 Prostatic Hypertrophy . 1 191 ./-Ray Treatment of ( loiter 1 P. Mi Pernicious Anemia . . 1 19(1 Hodgkin's Disease and Pseudoleukemia and L\ mphosarcoina 1 PtS I'olycyt hernia 1199 ./-Hay Treatment of Leukemia . 1200 Kpithelioma 1200 Radio! herapy with the Tube in Direct ( 'on tact wit h t he Body 1217 Technic of Direct Applications 121S ( 'arcinoma . .... 1220 ( 'arcinoma of the Breast .... 1222 Recurrent ('arcinoma of the Larynx 1227 ( 'anccr of the Tongue 1229 ( 'ancer of the Shoulder 1229 Secondary ('arcinoma of the Mediastinum 1229 ( 'arcinoma of Stomach and Intestines 1220 ( 'arcinoma of the I" ten is 12.'30 Sarcoma . 12:31 Treatment of an Inoperable Primary or Recurrent Sarcoma . Melanosarcoma Multiple Pigmented Sarcoma Fluorescent Medicines in Connection with ./'-Ray Therapy. . 12:3") Nature of the Radiance from Fluorescent Substances . 12:3(1 Influence of the Injection of Photodynamic Substances into the Tissues before .r-Hay Kxposures 12:3S Radiotherapy in Infectious Diseases . 12oX Specific Immunity . 12oX I! (Int gen Applications for Producing Sterility 12oX R \mr\t . . 12:39 Radio-activity 12:39 Origin and Cost of Radium 12 IS Variations in the Radio-activity of Radium 1219 Chemic KfTects of Radium Rays. . 12.").") Radiographic Kffects of Hadium Hays 12f>(i The Theorv of Radio-activity 12">7 Physiologic KfTects ,,f Hadium. . '. . 1LT.7 FtTects on Microorganisms 12">x Kffect on Plants 12(10 KfTcct on Toxins 12(10 Kffect of Radium upon Animal- 12(10 KfTect of Radium upon the Kve 12(11 KfTcct upon Animals During the Stage of Development and ( >n>\\ th. 12(12 Pathologic Kffects of Radium 12(12 Thi rapeutic 1'ses of Radium . 12(>:> \pparatu< for Therapeutic I se of Radium 12(1:! The Dosage of Radium Radiation 12H."> Radium Therapy 12(19 Hadium in the Treatment of Lupus 12(19 Radium in t he Treat men) of Skin Diseases 12(19 M ilignanl Disease 1271 Ha 1 1 in m Puncture for ( 'arcinoma 1 27(1 Therapeutic ("sc of Normal Saline Solution K \posrd for T\\ o \Veek- to ilie Radiation from Radium 1277 Radium in Kve Di-ea-e- 1277 Radium in I 'terine I'ibroids 1 277 Radium in N'er\-oii- Diseases 127X Tonic l.ttirt Tpon the Heart 127X Substitutes for Radium 127X . 12X1 MEDICAL ELECTRICITY AND RONTGEN RAYS GENERAL CONSIDERATIONS MKDIOAL electricity, or electro-therapeutics, treats of the applica- tion of electricity to the diagnosis and treatment of disease. Electricity is known to us through the effects produced when an electric charge, electromotive force, or potential is developed, just as the attraction of gravitation is known to us through the effects pro- duced when a body is raised from the ground. Hodies in which an electromotive force or potential or electric charge has been produced are no longer in a state of repose, but tend to produce a variety of effects, one of the simplest and most direct of which is losing their electricity to some other body or to the earth, or. in other words, becoming discharged. Many other effects are produced by the electro- motive force in seeking a state of equilibrium heat, light, the .''-ray, mechanic motion, chemic changes, physiologic effects. Practically, every one of the effects produced by electric discharges is used in electro therapeutics; and some recapitulation of our knowledge of electric science is necessary to the proper presentation of the special methods of producing and applying electricity in medicine. ELECTRICITY Electricity is sometimes regarded as a substance consisting of ex- ceedingly minute negatively charged particles, called electrons, which are a very great deal smaller than atoms in which they normally are in a state of equilibrium, with a positive charge which is inseparable from the atom. And when by the application of various chemical and physical forces the state of equilibrium of the electrons is disturbed there are various manifestations of [lower, such a> attraction, repulsion, heal, light, electromagnetic induction, and chemical dissociation or elect rolysis. The electron- are the same regardless of the nature of tin 1 atom- in which they are found. The underlying fact in the case of a cur- rent of electricity i> a flow of electron-- from the negative pole of the battery or oilier generator through the external circuit to the positive pole. If thi< tact had been known ui the I >eginning this would have been called the direction of the cuiretit instead of the reverse. h H an untoriunale misnomer, but doe- not make much practical exc< |)t in considering the pa age of electricity through a vactmii 1^ MKOICAL KI.KCTHICirV AM) UOXT(;EX KAYS like ill- 1 ("onlid^e .r-r:iy tube. There the electrons travel from the negative terminal, and by their impact upon a target u'ive rise to vibra- tion railed the .r-ruy. and also heat up the target, frequently to in- camle-cence. And it seems ridiculous to call the contrary- "the direc- tion < if tin- curn-nt ." Th>- various familiar means of "generating electricity" are means of freeing the electron- and applying force to them, which they, in turn, exert in 1 heir peculiar manner. Accepting the time honored classification of positive and negative, the electron- are negative particles of electricity: a neirat ively charged body contain- an excess of fi-ee electrons and a positively charged body contains le-s than its normal quota. "There are t\vo kind- of electricity, positive and negative. Each ordinary atom contains a number of electrons which are always negative, and enough ]>o-it ive electricity to exactly balance the negative electricity of the electron-. At present it appears that the positive electricity never leaves the atom, while the electrons allow themselves to be taken away or added to with relative case 1 ." ! An electron i- about rrriMVi the volume of an atom, but it is so much denser than an atom that its weight is ._,, ,',,,, that of a hydrogen atom. I' i- sup]>osed to be -pheric in shape. A charge of electricity is either a surplus of elect n ms. which is a nega- tive charge, or a ileticit of electrons, which results in a positive charge. A current <>i electricity is a movement, transfer, or passage of elec- tron- from one place to another, either free or in negatively or positively chartrei 1 at< 'in- < >r i< ins. Electricity manifests itself in three principal forms, covered by the name- of .-!. '''<, and fnr/nlic electricity. Static electricity is ;. at re-t , : n tending to a sudden discharge and resumption of eiertric equilibrium. Voltaic electricity is electricity flowinir or _ Ho\\ in a current. Earadic electrii'ity is a deri\"ed form of ci;rreni electricity ;n \\hich there are rapid alternations of direction a- applied in medicine, almo-t always relatively hiii'h ten-ion. There are -everal tiioi lificat ions of the-e which may be produced by -ui?:ii in-es, and ainoiiu- them are I.eyden jar di-charnc- and -fi'eijuency current. Then, again, the secondary : '. liiiht. the .r-ray, and other radiations and luable application- in many different condi- i 't tricity ilo\vn to about a century au'o was the Thales. one of the seven wi.-e men of ' -' to i -ail at tent i. >n to the fact t hat a piece of amber a! t raci ;;^i.i limlio. This wa.- in liOO B. c.. but no ' 'hed to the fact . About :>00 n. < . Theo- ob-ervation thai lynthuricum pi - obalil>" our -anie property. This i- all the pn-iii-e-s ric scieiicr il< ,wn to the time of 1 )r. ' iillieil . 1!) physician to Queen Kh/.abeth, in 1 (>()(). His investigations showed that many substances possessed this properly, and tho-e in which it could readily be produced he termed "electrics," from the ('.reek electron, amber. Among "electrics" art; amber, sealing-wax, glass, the diamond, hard rubber, sulphur, resin. Any of these, when rubbed with silk or fur, become- electrified, and exhibits at once; t IK; pro pert ie> of attracting light bodies which are not charged with electricity, or which are charged with electricity of the opposite sign, + or (posi- tive or negative), as the case; may be; of repelling bodies charged with electricity of the same sign; of inducing an ele:ctric e-harge; in neighbor- ing bodies by a pn>cess which may be like-tied to an attraction of the; opposite electricity in the other body, and a repulsion of the; electricity of the same sign; and of giving sparks or discharging the whole; or a part of its electric charge to other bodies brought near enough to it. These 1 sparks are accompanied by sound and a smell of o/one, and sensation and perhaps reflex muscular contraction if applied to the human body. A fine examples of the- production of electricity by friction is obtained when one walks over a woolen carpet, shuffling his feet, and producing a spark sufficient to light the gas or to give quite a smart sensation if applied to a person. " Anelectl'ics " is the name give-n by ( iilbert to t he; metals and < it her substances in which he- was unable; to excite an electric charge by friction. We know now t hat the reason was t hat these bodies are- good conductors of electricity, and that the charge was carried away as soon as it was produced. A me-tal or any other good conductor may be charged with electricity by friction, provided it is insulated. But all substances are 1 not equally charged, and they are' not all charged with electricity of the same sign or polarity. Those which would be covered by Gilbert's name', "electrics."' dove-lop the greatest amount of electricity when rubbe-d. and among them the modern hard rubber is perhaps the most active. From the start, it. was ne>ted that glass rubbed with silk, and resin rubbed with cat's fur, became- differently charged and attracted each other, while two electrified pieces of gla-- repelled each other, as did two electrified pieces of resin. To these two different form- ot elec- tricity the 1 te-rms vitreous and rcxinoitx were! applied. l.ate-r. when it was found that they we're- complementary, and that two equal e-harge-s neutralized each other, the- vitreous ele-ctricity was called positive, and given the sign plus, while the- resinous electricity was called negative, and given the sign minus There i< no special reason why either one should be called positive. The mimes might jusl as well have- been reversed. \\hen two dissimilar bodies are rubbed together, one- becomes charged with positive and the oilier with nega- tive- elect rich v On the two-fluid theory, friction separated the posi- tive and negative fluids, and an excess of one fluid remained in one body, while an excess of the 1 other was formed in the other body. { hi the; one-fluid the'ory an excess of eh'ct which becomes positively charged, am body which becomes negatively chargei Ironic theorv of electricity will be pro- transmission of electricity through ga- !, 20 MKIHt At. KI.Kl TKHITY AXO R(")N'T prime conductor of a static machine. The pit h -ball immediately swings over in contact with the prime conductor, and as soon as it touches it i> auiain repelled. According to our diagram (Fig. I), the positive electricity in the prime conductor attracts the negative elec- tricity in the pith-ball and repel- its positive electricity. \Yhen The piti.-ba'.l come- in contact with the prime conductor, it- negative charge enter- into the prime conductor and neutralizes a portion of 1 he positive charge therein. The pith-ball, being then entirely charged it po>itive electricity, is repelled by the prime conductor. In Fi r lately to one ;. : : c other, becoming charge' I at t he first contact with i" -hive elect ri it . and then being attracted by the negative pi i. where it loses its positive charge, and. acquiring a negative repelled bv the negative pole ami attracted by t lie ; ;ive. 'I ' -; : te rep tlsimi of two similarly chai'ged bodies forms t he ' i' 1 he iti-1 r'lliient callei ! 1 he elect n isci ipe. The electroscope Fin. > consists of a glass case in which a bra-- rod terminate- below m two pieces of old-!caf. and above in a brass knob. Un britiii'iiig the brass knob near a positively charged body, negative i- a< t r.n-i < i i po-itive charge being re- Ipoii become \ 11 i- neiuhbi irh< ::<-t her. I .lit if the <_da-- , ' . in : pririn cotiducli it 1 , c >r had recei\ ei i a iiild liave 1 ieci niie pi .-'i! i\ . -\y } ; \ < remained divi -r^, sit :i : u- i-eli lo-l 1 vil h -ollie coin lllcl iii- -lib- 21 In \YulCfs electroscope 1 the u'old-leave- are replaced by two quint/ filaments coated with platinum. The filaments are fa-tened t ( > ,-i conducting rod at the top. and are al.-o joined together at the bottom, where there is a light weight, pi oducing a uniform tension. An electric charge causes the filaments to div< Tge most widely at their middle (joints (Fig. \ > . The amount of thi- divergence i- observed by a microscope magnifying 70 time.-. The objective of thi- micro- scope is of low, and the eye-piece of hiidi. power. In this wav the objective may be at a convenient distance from the filament-. Another example of the repulsion between bodies charged with the same polarity is seen when one's hair --land- on end under treatment by static electricity. The discharge of static electricity produce- ;i s]>ark. with a development of noise. li'ht. heat, and chemical effect-. [Muscular contraction and sensation may al-o be produced. An early type of static electric machine con-i-led of a cylinder of glass, which, as it revolved, was rubbed by fur or silk, and thu- became charged with electricity. At another part of it- revolution this electric charge 1 was carried off by metallic comb-, which were -o near that the electricity could lea]) aero-- to them from the glass. The combs were connected with a, metallic ball, both being insulated. and the rubbers were connected with another metallic ball. The-e two formed the poles or prime conductor- of the machine. The whole would produce a very small amount of electricity, but enouirh to pro- duce the characteristic effect- of -tatic electricity. A bodv charged with -tatic electricity may produce a charge in another body, iir-t. by conduction or convection: second, by a -park discharged: third, by induction. The charm' produced in tin p ' conductor- of the old static machine- illustrates one and combs becoming ''haruvd bv a spark discharged trom the Li!a prme conductors receiving their charge by Figs. .") and l> show what take- place when a body i- cl conduction or -park from a body already charged. 'Tli. \\ uliT. I'hv.-ik, 7. ii . Vpri I.'.. l'.iT '__' MKDICAL KI.K< TKH ITY AND KONTGKN KAYS positive pole of a -tatic machine, and l>. an in-ulated metallic object. The proc-'-- i- twofold. There is an attraction oi the negative elec- tricity in t> to n, and a pa.--aue of a part of the positive electricity in fi into t>. The re-ult i- that /* lieconi"s charued with po.-itive electricity and remain- so after removal from the neighborhood of a. The positive charge on y induction is shown liy the ex])erimenl of hrinu'lnu an in-iilated liody /' in tlie diagram < ' Kiu1 if it is now removed from the neighborhood of . it- electric charge would a.ii'ain become in ulral. ['.in if /< were loiu-hed by a conductor, c. at any time while under the intluence of the po-iti\-e charuc in a, it- positive charge would d into the conductor, and an additional negative chaf. ' ei| I'M"-. v tVi iln t he ci illdllcti >r. The lat ter : ' . and if How. I he in.-ulated bodv, Ii. \\hich i- ' ' :ia1 ive eled ricit y. I ie ca rri< 'd to a i li-t ance 1 1 d -upp< irt \- \/< *. depend on these principles. Two bodies, b and r, separated by a sufficient air-space or by sonic other dielectric ('Fig. 1(>\ may be influenced, the one by //, positively charged, and the other by d. negatively charged. // being brought in contact with b, and d with r, b becomes completely charged with posi- tive electricity by conduction from clcci rifled, its charge has a tendency to accumulate wherever ii ha- -harp puints, and when any other body is 1 ' /.''r conductors of electricity, and an electrified body will, ii' insulated by either of these two, lose its charge very slowly under ordinary conditions. Air may become a good conductor in seyeral dift'ei'ent ways, one of the most interesting being!')- ionizjition of the air under t lie influence of the ,r-ray. 1 he discharge of an electroscope and the Calling together of its leaves under ionixation of the air by the x-ray have been pro- posed as a quantitative measure of the latter. Among the conductors are metals, charcoal, graphite, acids, water, and the human body. Among partial conductors are linen, cotton. alcohol, ether, dry wood, and paper. Among mm-conductors are oils, porcelain, silk, resin, gutta-percha, shellac, hard rubber, paraliin. glass, and air. An electric charge passes through a conductor easily and quietly, unless the conductor forms too small a path for the quantity of electricity passing through it. In such a case the conductor becomes hot. In the case of a non-conductor, practically no (low i- permitted unless the pressure or tension is yory great, and then the electricity does not pass by conduction, but by a di>ruptive discharge. It seems to break through the non-conduct or. ami in the ca>e of violent dis- charges of electricity, as in lightning, the effect upon non-conductors is most destructive. Conductors are used for the passage of electric charges and currents. Non-conductors or insulators are used to protect the charged conductors from contact with other conductors, and thus to retain their electricity. Foi all practical purposes the earth may be regarded as an in- exhaustible storehouse of boil: positive and negative electricity. In a static machine a charge communicated to both poles is much in- creased if one of them is groiini led nv connected wit h the earl h. \\ hen two perfectly insulated dissimilar bodies, are rubbed together, a nega- tive charge will be produced in one and a positive charge in the other. bv ;i, process which may be regarded as a disintegration of a norn al neutral charge in both into positive and negative charge- all the positive electricity of both beinu' accumulated in one body and all the negat ive in t he other. If. now, one of these bodies, say 1 1 e live one. is grounded, an additional amount nt negative elect] enters it from 1 he cart h. att racled into the negat ive pole by 1 charge in the other pole, and then with a stronger nega'ive : stronger positive charge i- produced in the other by in J(i MKDIC.VL KLKCTHU'lTY AM) K<)N(.TK.\ KAVrt is assuming, of course, thai the process of friction is going on while t ills gt'' 'Ulid ci 'lined h >ll l> made. It appears to be universally true that the development of the pnsit-ive ci:arge of electricity oi any lorm whatsoever is attended e development of an equal negative charge. An electric charge exerts H force -its dtclmnmti '( J'orct tending to produce again a neutral -tate. In the case of static electricity, the charge is altoget he: 1 on the .-nriace of tiie electrified body. This may be due to the repul- simi \vhicii an electric charge exerts upon electricity of the same sign, either positive or negative, and tiie tension or pressure of static elec- tricity is so great that this repulsion repels practically the entire charge to tiie surface. Static electricity nmst be considered separately from dynamic electricitv because it is only by the so-called static machine; that such verv high voltages can be directly and readily obtained. The very existence of a useful charge; of static electricity requires that the charged body shall have b<>th capacity and insulation. The differ- between electricity in the form of a current and electricity stored up as a static char ire is comparable to the difference between water p ured through an open ring and water poured into a cup. " A cupful > :' water" implies that the cup is closed at the bottom, and "a charge of -tatic electricity'' implies that the charged body is capable of retain- ing the charge, i'seful charges of static electricity are of such high lies thai the requisite degree of insulation can be conveniently obtained only by means of apparatus dependent upon the excitation of non-conducting plates of glass, hard rubber, {taper, or mica. THE LEYDEN JAR A class jar. coated on the outside and on the inside with tin-foil ' ,ab ''it naif its height, and with a brass rod fastened to the cork and connected with the inner coat by means of a loose chain, the - i'"d lerminating above in a knob, constitutes the apparatus , : l.eyden jar. To charge it, the knob on the upper end of the roil is brought near enough to one pole of the static- machine to receive a charire by conduction, convection, or by spark tT'ig. \~). .' tl e - me time t he outer coat of tin- foil is grounded by holding ' jar in the hand. The inner coat becomes fully charged with p<>si- t ive electricity if it i< t he positive pole of the static machine which is I 1 e . uter coat, separated from it bv onlv the eighth of an ' ness "l the glass, becomes negativelv charged by induction. I ins negalive charge of the outer coat is attracted into it from the ground. The two charges are a very greal deal stronger than eit her would be alone, in coii-eotience of the attraction of the two for >.. . oilier, and the consequent condensation of eledridtv. Mich a charged I.evden jav will ret ain i' - charge for a long time in spile of 1 he fact thai r is e.-ti'ried about and handled by the outer co^t ing, 1 i< -et down on a glas< |ilate or sonu; o1 lier in- \ the knob c. .nncct e. I wit h 1 he inner << >a1 hig : ny d i-charge occurring. Touching both (I e i connect e(i \\ ith t he inner ci >at ing at 1 he STATIC ELECTRICITY '27 same time will produce a discharge, which, in the case of a Levden jur dt iiuy size, occurs us u very brilliant, while, largo spur k. Such u discharge produces physiologic effects, the ino.-t manifest of which, with a .small jar, being a single muscular contraction of the forearm, hut, extending, with a lar.^e jar, to the muscles of the arm and even to the chest. A very large Levden jar gives a powerful shock, and so does a haltery of Leyden jars with their outer coatings all connected with one terminal and the inner coutings with another. The violence of a discharge \viil ilepend upon the area of lead-foil in the Leyden jar or jars, and the tension of the charge. A whole group of people may receive a shock at one time if they join hands in a ring, and the outer coat ol a large Lev den jar he grasped hv one person, and the person at the other end touches its inner rod. Experimentally, a whole regiment of soldiers have heen given a simultaneous shock in this way. To avoid disagreeable shocks, Leyden jars should never be left in a charged condition, hut should be discharged by a special curved metal rod with an insulated handle made; for this purpose. Leyden jars form an important part of the apparatus for treat- ment by static electricity and by the modern high-frequency currents. If a Leyden jar consists of a glass tumbler with a loose inner coating in cup shape, and an outer one of the same nature and is charged in the ordinary way, the inner metal coating may be taken out and handled, and will be found not to possess any electric charge. The outer coat may then be removed, and will be found to have no charge. The entire charge remains upon the two surfaces of the dielectric, the glass, and on reassembling the parts of this dissected Leyden jar, it may be discharged in the ordinary way. The other type of condenser, consisting of some dielectric sheets of mica or paper, between which are sheets of a conductor, like tin- foil, are used where a very large surface is required, and where 1 1n- tension is comparatively small. Such condensers will be described in greater detail in connection with induction coils. NATURE OF ELECTRIC SPARKS The discharge occurring between the two poles of a static machine varies in accordance with their distance apart, ll they arc very close together, there is an electric arc: if a litlle further apart, there is an almost continuous thread of white light. Separating the poles an inch or two. the discharge changes to a thread, or a number oi threads, of violet liu'ln. with hrilliant white sparks at each pole. I: a bit of wood, like a match, is held close to 1 he positive pole, the spark will be deflected toward the wood, hut little or no effect is produced hv wood held near the negative pole. If a pointed metal elc connected with 1 he earth is held anywhere near the positive pole, a bright violet light, like u star, appears upon the point, ai d \\ ei : brought almost in contact with the positive pole, a bright vhite co t intu His thread discharge i akes place. \\ 'hen t he same i electrode is brought near the negative pole, the star does noi ; unt il the point is within a few inches ot t he pole, and \v en n still nearer, a violet brush discharge takes place fro] ; negative pole,. he- discharge- occurring bet ween t he two poles of a static machine, l he 1 are separated bv a considerable; distance, is best see-n in ciied root i . The whole space bet we -en t tie 1 wo poles is filled by a-.- of violet light. From the positive pole; there; shoot iiicou-lv pe-rhap.- a do/en xigxai: threads of violet light, < . : ,.'.' e; r: nee likened to a fox's tail, while; the; discharge; from .-"at : pi ile i- -imply a diffused eliluve of violet lig'nt. ( 'onne-ct- e inner coat oi one I.eyden jar with the positive, and the; inner er I.evden jar with the- negative, pole, and connecting oipe-r coat- i< Aether or buih in t he e-arth, the discharge between io[e- MI a -'.' '' machine- ceases to be a continuous one-, and be- >- a -Ucce--i .n of briiliaiit large white; sparks. The-se .-parks are- e -;:' e a- ' e is the . r positive and n the negative- pole- of a static machine. As the- e-le-dric charge i- produced by the operation of the mae-hine, the- inner coat of the- l.e-yde-n jar, /. is positively e-harge-d. and the- nega- tive elee-trie-itv in the; out e-r coat s of bot ii jars, conm-cted by a brass rod. is at- tracted to the outer coat of /, and this strong negative- charge of it- outer coat -till re 1 e capacity of the inner coat for peisit ive electricity. -..: ,e proce-- -..i.e- place; in the- I.eyden jar. /. whose inner coat .e- a c e.. . iie-gat ive charge 1 , and whose outer coat receives the ge- of both jars. \\he-ntheniaehineisturnedori.itis ' a' en irusli or -park di-ediarge does not take- place i- space- he' we-ej] the pole- of the machine. The- charge is ' red up iti the- two I.e-yde-n jars, and in eae-h one- is bound by " I'a'-i loti ( -.. N between the positive ami ne-gative; charge-s, a'ed onl\ ; r the: 1 !ijckne-ss of a sheet of glass. Fve-nt uallv, t he- ir-ciin c - harge-d and a dise-harge occur-. A brilliant . pa--e-~ a e- -pace 1 be-twe'e-n the- pole- of the- machine. ; - xi'_ r xaL! line. At the same time a crown of zigxag. lies -tarts upward from the uppe-r e-dge- of the- jar. The; inner coat- have- parted with e i ft 1 v by discharge from the- mnm-r coat of ''..' '-I the- oppositf-Iv e-hai'U'e-d one. through the- : t lie: machine- and the- intervening air-- pace, and > miter to the- inner coat of the same jar ! e tila--. The latter, in each jar. is a consequence er coat, which leave- an excess of charge oiind bv the attract iein of the- internal 1 .'(-- I arge of the- opposite- sign is liberated ' e i . ' i- j uce i >f both I.cvden jar- and part of r , < exe-liaiiged and neutrahxed through Ti e rod. although large- enough 1" carry . ' ' of elect rich y in a quiet cnrre-nt . ce : ,e i ij icvat i\-e. de\'e-lo] is an e-nor- e ' ' i pa age- ' <\ -lledi a d i-chal'ge as tin oi t he- d ischarge ca n be .-e'en 1 : f stirfae-e- of 1 he glass. STATIC KLKCTKICITY 2.J The resistance of the hitter path is great, but ;i portion of a discharge simply cannot gel through the brass lod, and has to leap aero.-.- ll,e space described. Leyden jar discharges modified by inductive im- pedence in coils and the like for in the modern high-frequency appan.t u-. If t he poles of the static machine are loo widely separated, no discharge will occur. The Leyden jars will simply hang there in a fullv charged condition, and in the dark, of course, a convect ive discharge can lie se'Mi leaking into the an 1 from ail point- or rough place.- in the poles or jars. When the poles are brought nearer together, the flashes again take place, and are at first loud and brilliant, and at long intervals perhaps only fifteen in a minute. As the poles are "brought nearer and nearer, the flashes become less brilliant and more frequent, and at a distance of half an inch or an inch they form a continuous stream of white light with a very rapid succession of reports, which are not a- deafening as when the distance was greater. If a static machine has beeii running with the poles so wide apart that no discharge occur-, and is then stopped, the Leyden jars .-nil remain charged, and a fla-h will occur on pushing the poles toward each other. \\ hen a Leyden jar is discharged by placing one end of an insulated metal rod in contact with the oilier coal and bringing the other end near the knob connected with the inner coat, the spark which is produced does not completely discharge; the jar. and after a minute or two a smaller spark or residual discharge may be obtained in the same way. The electric spark produced by the discharge of a Leyden jar or any other condenser appears like a .-ingle flash, lasting quite an appreciable length of time. Experiments in which the spark i- observed bv means of rapid.lv rev< ilvmu 1 imrr< >rs do not sin >w the reflec- tion of the spark as a bright spot, which would be the case if the dis- charge were instantaneous. On the contrary, the image appear- drawn out into a line, and measurements which have been made indicate that a Leyden jar discharge, between bra-.- knobs five milli- meters or one-fifth of an inch apart, lasts about one-twenty-four- thoii-andth of a second. The same kind of experiment upon a buig spark shows that it begins simultaneously ;it both pole-, and is visible later in the middle. Static electricity travels through the air and through most metallic conductors at the rate of ]ss.(H)n miles ;i second. so that the difference in time between the appearance of luminosity at the middle of the path of the spark and. at the two ends is very - till indeed. The discharge take- a xigxai* course, just exactly as the ca.se with the lightning flash, because of the varying resist a i caused by the condensation of the :iir before it in different parts \<\ its path. A spark passing through a part ial va a straight litre, Oscillatory Nature of Spark Discharges. -A siiucl* 1 spai by a Leyt len jar represents millions of t the lightning flash across a mile or oscillations. Two oppositely but eqtl bet \ver-n which a pith-ball i- su-pen Je both become nenira.l in consequence 1 o h tia ' fst touch ). a 30 Mi:i>I< VI. KI.KCTRICJTY AM) KO.VH i K.N HAYS I IL_'. 111. I'ith h;,ll M.-rilhitillK 1 nt this negative charge is communicated to the pith-ball and carried ad'i >-- t ii f>. I ho n cut rah/ at i< m of a Ley den jar charge is accomplished by a somewhat analogous sci'ics oi oscillations. It is t ho enormously high l'rc(jiiciicy of these oscillations, millions a second, t hat Divest he name to " high-frequency ' curi'ents. This subject will be dwelt upon in an- <>t her chapter. Any electric spark in the open air produces discharge rnifx, which are described elsewhere and have some of the properties of the .r-ray. The Electrophorus.- If a mass of melted resin is poured into a metal plate and allowed to cool, it may be charged with negative electricity by rubbing it with cat's fur. If a metal disk, somewhat smaller than the resin, is placed upon its surface, the neutral charge of the metal disk becomes separated into a positive charge, induced "ii its l<>wer surface, and a negative charge, on its upper surface. While the disk is in this condition, if it is touched by the finger or some other grounded conductor, its negative charge will be removed, and an addition made to its positive charge 1 (Fig. 20). The negative charge on the res in i- not communicated to the metal disk because the rough and uneven surface of the resin prevents contact except at a comparat ivelv few scattered points. '1 he resin is so poor a conductor thai it- charge remains fixed on the different parts of its surface which do not come directlv in contact with the metal disk. The 1 !_. _' '. ' _ ' ' : :.. inis. negative charge mi t lie resin attracts a comparatively great charge o! : " - . ; e elect ric it y 1 1 it o 1 he disk placed on it s surface and connected / the gr ;::. The positive charge on the disk in turn exerts an induct ion upon t lie e-m , increa-ing it - ne<_ r a1 ive charge by at 1 r act ing negative eh-d rich ' ;: n the earth through the outer metal plate, containing the re- u. had better not be insulated. The t her Around conned ii m. is to be removed while the disk is - . ' . I he (I - then removed bv means of n> ghi-s ' ' have c|uit e a ch;i rge i if pi isil ive elect rich V. I p e u-ed to t_ r i ve a -park. ;i- in 1 lie dia.gr am (Fig. '_' 1 i . or to . a Lev ;cn jar. A long -ucce->ion \\\ \ \< -it i\ c charge-; ma\' thus lie u : f-i ] ': ' c met al < : : - . an ; u.-ed to charge a lar^'e I .e v len jar. t he i cigi lal -mgle charge of negati\e e'lec- iced upon the re in b\ fridii n. 'I hi- principle i- the ' ' ' ' lern I at ic or in Hueiice machine. THP: MODERN STATIC OR INFLUENCE MACHINES The a! CM ii can 1 10 < il it aineil by frid ii >\\ is ' mp;irr-i] il he Amount of work recjuired to produce it STATIC ELECTRICITY 31 that the apparatus dependent upon this principle is impracticable, but a small charge of static electricity originally produced by friction may be so increased by means of a suitable- induction apparatus as to be- powerful enough for e;very medical purpose;. In the static machine; of the; simple; friction type; a positive; charge; is preulue-eel upon a involving glass plate; by frict ion. This positive; charge is carried by the; glass to the; place; whe;re; the; metal collecting comb of one of the; poles is ne-ar the plate; ( Fig. 22). The; posit ive charge upon the plate separates the neutral e-harge- of the e-omb and >iiih prime conductor, inducing a negative charge; in the; comb and a positive charge in the pole (Fig. 23). The negative charge; escapes from the points of the comb as a static bree/.e or brush discharge, which, passing to the surface of the plate;, neutralizes the positive charge there and leaves the plate ready to be; recharged by friction at anothe-r part of its revolution. The rubber, of course, is negatively charged, and is e-onnected with the othe^r pole of the machine. iir. 2-k- Di:iirr:iiu ol inllurm'o tvpc ut stulii' inurhin . In one tvpe of inlluence 1 machine there arc t\v< |>!ale- pape>r or of met al foil [>asted upon two separate -t al (Fig. 24). These; fie>ld-plate>s are slightly charged ". \\ h. with neative olectricitv. A third insulated [HIM-I- oi 32 called a carrier is fastened upon a revolving glass plate. This carrier is iir< 'undei 1 or connected \vil h t lie cart li when it is < ipposit e a . and, b ke the metal disk nt' an electrophortis, will ha\'e a small charge of free; elect rich v after it has moved past . \\hen it has made part of a revi ilut ion. a collecting brush conies in contact with the negatively charged carrier. This collecting brush is connected with the negative! field plate >>. to whose original small charge is added the major part of the charge brought liv the carrier, which in this way becomes less full\" charged. ('< iiit inning its revolution the carrier comes opposite the negative held plate //, with which it is no longer in connection, while, nil the other hand, it is again grounded. I'nder the influence of a somewhat increased negative charge of h a somewhat stronger positive charge is induced in the carrier -positive electricity being atl r acted into it from the eart h, and negative electricity being repelled from it to the earth. While the carrier is opposite h, this positive charge is bnund or fixed upon the carrier by the attraction of the oppositely charged held plate, just as is the case with the charge upon the two coats of a I.evden jar. After it has revolved past h and is als" no Joim'er grounded, the positive charge upon the carrier becomes free and is carried by a collecting brush, which comes in contact with it to (i, strengthening the positive charge already present in that tield-plate. \\ith a rapid rotation and a mechanic construction which permits of very little leakage; of electricity by conduction, the field-plates soon acquire a very powerful charge. I'l'i'in the beginning a carrier, when negatively charged, gives up onlv a certain portion of n < charge to the collecting brush, leading to th" negative field-plate, so that both the carrier and the field-plate : a' e ! he same charge m pro port ion to 1 heir si/e. The unappropria.t ed negative charge upon the carrier is taken up hv 1 he combs of the ' conductor before the carrier reaches the part of its revolution, ' " .' a'jfain come- un ier an inductive iniluence. This charges the negative ple, and the positive pole receivers its charge in the same '.vay, through a comb applied at the opposite part of the carrier's ,'i<'!;. 1 !:e two poles are the [daces at which the two opposite '"-."-' are tieare-1 together, and where 1 hev exert their greatest at ; raci ion lor each ot her, and \\' here a discharge occurs when sufficient ''' - produced to overcome the resistance of the intervening I he a' o| the charge in the opposite pole is a :il tactMf in the pa--a^e of the unappro[)fiat ed charge from the ; -' ' ' ' '''' ' ' ' prime conductor. In this transfer from '' ' ' ' prime e pn >ce - may be regarre ' ' e ci inneci i> .ji made bel ween the t w i oppo- ' '' ' ' ir of neut ralixinu; 1 irushes j< lined 1 >\- a ' x.i- ' ' alt racted iut o i: t he poout two inches wide, with their outer edge about an inch internal to the outer edge of the stationary plate. Kach of these strips occupies about one-fourth of the circumference of a circle. A strip of sheet metal is pasted directly upon the glass along the center of each strip of paper, the sheet metal forming a strip about half an inch wide and five inches long, with somewhat larger extremities. The revolving glass plate is about an inch and a half less in diameter than the stationary one, and is at a very small distance from it. I'pon its front surface, that is, the surface away from the stationary plate, there are pasted eight carriers strips of metal about three-fourths of an inch wide and two inches long, arranged in the direction of 1 lie spokes of a wheel. As this plate revolves these metal carriers are rubbed by four different wire brushes; two of these are neutralizing brushes, the other two appropriating brushes con- nected with the two field-plates. There are two combs not shown in the picture for collecting the unap- propriated charge from each carrier, and leading it to the field-plates of the Holtz machine. This Toepler machine is operated by hand, and a few turns of it generate' a sufficient charge to enable the Holtz machine to start up promptly. The Toepler machine, it will be seen, is self-charg- ing: the friction of the brushes upon the metal carriers and also upon the glass surface produces sufficient electricity to start it, and this is rapidly multiplied by the induction which characterizes every form of in- fluence machine. All these modern types of static machine are capable of producing very powerful charges when a num- ber of large plates are used, a high rate of speed is. produced by electric which they are contained are air-tight, and the machines are kept free from dtist and moisture. The large powerful machines so commonly used in America are capable of producing very much better results as a therapeutic agent and for the operation of an .r-ray lube than the smaller machines, usually made in Kurope. which can be lifted by hand and are hardly more than laboratory toys. The Wimshurst machine (Fig. -l>). in its simplest form, consists ot two glass plates of equal size, and very close to each ot her. revolving in opposite directions. Kach has a number of metal carriers pasted upon it. and these also serve the purpose of field-plates, and arc on the side away from the other plate. Kach plate has its own pair of the 3-1 neuirali/mg brushes, connected by a brass rod. There is ;t double collecting comb passing from each prime conductor to the t\vo glass plates. The comb from the negative pole is forked and extends close to the -urt'ace of both plates and receives its charge a carrier on each ..f the two plates simultaneously. There are no special field-plates and no appropriating brushes, bringing a charge directly from the carrier on one plate to any part of the other plate. The initial charge i- produced by the friction of the neutralizing brushes, upon the glass plates and metal carriers A> soon as any of the carriers become charged, they act upon those of the other plate by induction, in the way described as takhm place in the Toepler machine: and very soon a powerful charge i- generated and may be seen passing across the space between the discharging rods connected with the two poles 'Fig. L'Ti Like the Toepler machine, this is self-exciting, and is often employed to -'! fevoh-iim and -tationary plate-, u-uallv filaced ei e~ up ' t he -a ; f a \lf. ami 1 urned by an elect ric or Wat er mot or. I'. ' ' ' -mL r le couple i~ repre.-eiil ei I. I he stationary le - in t Wo -ep ile pi iTl i. ins, /. ti. r. ,1 , a!id i . /'. den r;i>e f 1 hi ' uchine b\' wooilen ami hard - rubbi et i n-ulate 1 hem. They do not come STATIC KLKCTHICITY oO in contact with any other part of the machine. The field-plates are two large pieces; of paper with a half-circle of sheet metal coyering the paper at one end. and turning over the edge of the glass at 1 lie edge where the revolving glass-plate first meets the field-plate. The field-plates are on the front of the divided stationary glass plate, and so are the semicircles of metal which are pasted upon their front exept in the first couple of the Holtx macliine. I he ti combs project in front of the rovolvinn plate at th.e p liottom, w'here the revolving glass is iu-t leaviim the ml field-plates. The collecting coml.s from t!e [irime 30 uiul .V project in front of the revolving plate at plares, at oithor side, where the reviving glass has just entered the influence of the field- plates, near the ed.ue (if the metal semicircles. There is no connection lietween the revolving plate and 1 he stationary plate with its field- plate. There are no collecting Brushes to carry the fret! charge on the revolving plate to the field-plates, hut this is accomplished by a convective dix-harijv or eliluve lietwen the revolving glass plate and the i net all ic semicircle connected wit h each field-plate. The revolving plate lieing of irlas<. is itself a non-conductor, and is made, still more s< i by a varnish nf shellac: and nothing whatever touches or rubs over its front or hack surface. At a certain stage any one portion of the revolving da-s plate may have a positive charge, which it has received by a convective discharge from the combs of the prime conductor and a negative charge induceil in it by the field-plate. This par- ticular part of the revolving trlass plate retains these two charges. bound upon 11- sin-faces by mutual attraction, just as is the cast 1 in a directed Leyden jar. where the positive and negative charges remain 'if'" 11 ;: -'' -'a-- after the outer and inner metal coats are removed. I.a'-h successive portion of the revolving glass undergoes various Taii-Iormat ions by induction and bv convective discharges, just as were revolvinj; in -pace sejiai'ated from everv other part of the same plate. Kleftrifully. each part is separateil as long as t he glass 'i'"i -hellace.l -urface are t'ree from dust and moisture. \Vhen ! '''-'' ''' ndition- are nut fulfilled, the Hnltz machine will produce only :t feeble dischartre, and fierliaps none at all. \\hen a multiple plate Holt/ machine is charged, it will not reverse [loharity -o lofijr a - it is runnitm and the sliding rods are separate.] >everal inches. When the atmosphere inside of a Holt/ machine ha- considerable moisture in it. the polarity mav reverse if the ~ : linjr rods an- broiijilil in contact. \\'hen a Holt/ machine loses it.s charire. then up-.n recharging it, the polarity may be reversed, but STATIC KI.KI TKIC1TY this is duo to the fact thai the polarity of the charging machine has reversed. The Holt/ machine itself will not reverse polaritv as long as it retains the; original charge. It must l>e noted that while we speak quite definitely about 1 he- way in which an influence machine generates electric charges, the subject is a purely speculative one. and the fads, if they could be known, might vary considerably from our conception of them. That when an influence machine, even with the latest improvements, is started up, one pole will sometimes he the positive and sometimes the negative is very curious. Any of the influence machines may be made with plates of other material than glass; hard rubber has many desirable features: it dues not attract moisture, and is not so heavy or so apt to break under the strain of an excessive speed of rotation as glass. On the other hand, it undergoes a slow process of degeneration, and is also liable to warp and lose its perfectly flat shape. .Mica plates are made of mica split in mfinitesimally thin pieces, mixed with powdered 'shellac or a similar substance, and subjected to an enormous pressure while healed to the proper degree. Machines with mica plates work excellent ly. and while one would Mippose that the plates wniild disintegrate in time. 1 he manufact urers say that t hev have never had a plate returned tot hem in this condit ion. The Paper Disk Static Machine 'Fig. MO). The static mac 1 h p made hv the Baker Flectric ('ompany i- a Toepler machine, and i- mclosed in a glass case, but usuallv does not require calcium rhlnnd inside the case to absorb moisture. A suitable machine for r-ray work i- known as an eight-] re machine, having four revolving paper disk.- and four stationary gl; 3!> Ml.DIt \I. Kl.Ki TKK'ITY AM) KONTi.K.N KA\S plates. The plates make 'JDOO revolutions a minute, a two-horse- power engine or motor being required to run the machine. Kxeellent radiograph.- of the t'oot can be made in six seconds, and of the chest in thirty seconds. Kach paper disk is made of about '24 full-sized sheets of bond paper, coated with shellac and other gums, to harden the shellac, for the latter does not harden unless exposed to the air. The whole mas- is compressed between hot metal plates and then allowed to cool slowly while under pressure. The result is a disk about { inch thick, which i- practically unbreakable. It sounds like a piece of iron when -truck by metal. Moisture has less tendency to condense upon it than upon glass. and the plate will stand the strain of 2000 revolutions a minute, while the normal rate with revolving glass plate- i- :).">( i revolutions a minute. The revolutions being five or six times as rapid, the discharge is more nearly continuous than from a glass plate machine. It is twentv times as nearly continuous as the discharge from an induction coil. The discharge from a powerful paper disk static machine through an .r-riiy tube is. therefore, more nearly continuous, and the heating effect on the ant icat hode is very great. Some tubes will traiismii Is milliamperes of this current, but after about thirty seconds it is found that the vacuum has dropped to such a degree that the .r-ray generated has no penetration, (le.nerally speaking, the tubes which will stand the discharge for half an hour or so give excellent Huoros.copic images, but make poor pictures; while the best radiographs are sometimes made by tubes which will stand the current for hardly thirty seconds without breaking down. wn is attributed to the fact that the platinum is r welded to the surface of the mass of copper for heat radiation. The cement in one case, or the flux the other case, gives out gas when heated and lowers the bes have been made with an anticathode in which the copper ng i- deposited on the platinum by electrolysis; the platinum per-plated. This does away with the evolution of gas from the jusl ment i' ined. noi her charact erist ic of the discharge is its comparative freedom -napping. I hi- is seen m the line xigxag sparks which pass e:i the prime conductor- of a static machine when they are ate : beyond the range of actual white sparks. With most glass machines there is considerable of this effect interfering This snapping is a sort the amount of metal The paper disk static apping at a distance of over thre of violet luminosit wever, the snapping at ome eteroraton, owng ases which are enerated a composite plate i STATIC KLKC'l'KICITV 39 that when static machines are made having more than two revolving plates, and having them made of a composite material, they mav possibly prove unsatisfactory, owing to the fact that the revolving plates are liable to perforate. The Size of Static Machines.- For ordinary therapeutic uses a machine with eight or ten revolving plates thirty or thirty-two inches in diameter, and making .'>()() revolutions a minute, is sufficient. Such a machine will also light up an .r-rav tube so as to make possible a fluoroscopic examination of the extremities, or a radiograph of the same parts and the chest (either a much larger static machine or a transformer is required for practical ./--ray work). Static machines have been made with revolving glass plates weighing a ton in the aggregate, and have given beautiful results with an .r-ray tube. A static machine with sixteen revolving plates thirty inches in diameter is powerful enough for all practical purposes. This should be furnished with a half-horse-power motor. Pole Changer. The polarity of a static machine cannot be volun- tarily changed, but, especially for .r-ray work, it is often convenient to use a pole-changer a jointed hard-rubber rod by means of which the connection of two wires with the two poles of the machine may be changed by simply reversing the position of the rod. The Care of the Static Machine. The modern influence machine gives a wonderfully steady output when in good order. --much more uniform than the current from the best induction coil. but it is very sensitive to atmospheric and other conditions, affecting the insulation of the surfaces of the plates. The machine should be completely inclosed in glass and wood, and this case should be air- tight. The room in which the machine is kept ought to be a dry one. and one on the second floor is sure to be better than one in the base- ment. If the case has to be opened for repairs, this had better be done on a clear dry day. and it should be left open as short a time as practicable. The muixtnrc in the air inside of the case has a tendency to collect upon the glass plates, and with it also the atmospheric dust and the metallic dust from the machinery itself. This deposit may cause? such a lack of insulation that the machine will produce little or no discharge. Several different ways of preventing this have been suggested, the best being by the use of calcium chlorid. a powerful absorbent of moisture. A generous quantity of this should be used. In a case measuring 2 x .'> x 4 feet, and containing a six-plate static machine, two pounds of dry calcium chlorid should be placed in deep open vessels. As time: passes this changes from a powdery while mass to a dirt y slush or melt ing snow appearance. After it has become completely saturated with moisture, of course, its usefulness is at an end. It may be regenerated bv drying in a hot oven, or it may be replaced by fresh material. Needless to add, if the calcium chlorid is bought in quantities, it must be kept in sealed tins or gla-s until used. A larger quant it v will be needed for a larger machine. A handful of calcium chlorid in a shallow saucer is quite inadequate to the purpose. It is very important to reduce the amount oi du<1 produced in a machine to a minimum. The use of aluminum in: of brass or iron for the pans of the machine inside the case is recommended wherever practicable. Aluminum dors not o.\ 40 MI. nil Ai. I.LKI i UK n\ AND Ki'NToiA KAY> or produce much metallic dust. With a properly constructed case achine and with an occasional renewal of the proper amount of calcium chirid a static machine should run for two or three years with" 1 ;: any fun her attention. At the end of thai time it may well require very complete overhauling. The inevitable deposit of metallic dust will have to he washed off of the plates and all the other interior parts of the machine, with a light additional coat of shellac appliei 1 to t he not been burning will be free from it. \\ith ;; static machine benefit might be obtained from heat if the air were heate ,. but :epi -eparate from the products of combustion. 1'his can be easily done by placing one or two :;_' candle-power electric lamps inside of t he g!as> case, wit h a switch on the outside, so that they can be turned on or oft' as required. In a very damp, warm climate, a >tatic machine may be thoroughly dried in fifteen minute- by mean- of compressed hot air. Inside the ease of the ma chini' at one end have an electric toaster supplied with the regu- lar electric liirhi current. At the other end pump in compressed air at a ; r ure of about '2~> pounds to the square inch. This can be done every day if necessary. 1 Another method is to keep from _'() to loo pounds of unslaked I- inside the ca-e of a static machine. This works excellently as -t>rbent of atmospheric moisture. The lime must be wrapped thic .'. es of cloth, t" prevent particles from flying all e ini erii IT ' if i he machine. I:. a:, emergency, for a -ingle session, a freezing mixture of ice and ' ::. leep L r la-- or earthenware vessels. -ndi as half a dozen pre-erve ja?'- pi iced inside the case, will cau.-e the moisture to condense upon ' e _ ve--ej-. and thus iVee the machine from moisture. If irla-s - are u-ed ' put the ice and salt mixture in. it i- always well to pi ' (! n -aUccrs or ['late.-, so that the iir-t condensation will be ' i en -.. r- in \vetting the bottom of the case. This will o:rr-!, - ;t \ e : e ; :; . but not alwa\ -. ' ;, -o many \vavs are recommended for dealing i-ture, h will be gathered that a static machine ' ' . 1 rider unfavorable conditions it will not :: > the time ihroimhout thestunmer. This i- lie -t ,-tiic : achinr- ha> been to a <:reat ext ent ai >an- : electricity for the ./'-ray. There is good reason er. tiiat a proper) v con-tructed .-tatic machine, e \viil \vork regardless of en \"ii'< inmem . Such N Po>ton i- in a ba>ement oldv a lew teet : ' he -i- t'er. and -1 ill ','. < >rks perfectly. The condition of the atino-phere e of the >tatic < . A \\.-i--. M. I).. .I. ,,ii ..i \,!v.iti'-.--l 'rin.nqiculics. October. I'.MJ. p. 117. STATIC ELECTRICITY 41 machine has, of course, much to do with the condition of the air in- side, for no case can be hermetically sealed, but the condition of the air of the room lias also an effect upon the efficiency of the applica- tion of the charge after it has been generated by the machine. If the air is very dam]), it ceases to be a good insulator, and much of the charge leaks away from the prime conductors by a convective dis- charge. The ideal room would be one through which the refrigerating pipe ran in summer, reducing the temperature of the. air to between <)0 J and 70 F., and causing much of its contained moisture to con- dense as a thick layer of whit e frost upon t ho cold pipes. All exposed metallic parts should be round and polished and kept clean. Metallic points or particles of dust would dissipate the charge by convection, \\herever any metallic parts of the machine which conduct electricity pass through the case, they should not come in con- tact with wood, but should be insulated by hard rubber. While wood is a poor conductor of electricity, the extremely high voltage possessed by static electricity requires the most perfect possible insulation. Starting an Influence Machine. In starting a Holtx machine provided with an auxiliary Wimshurst or Toepler machine, the dis- charging rods should be an inch or two apart . and after t he motor has been turned on and the glass plates have begun to revolve, the Toepler machine should be given a few turns by hand. Soon a series of sparks will begin to pass across between the discharging rods of the Holtz machine. After this the Holt/ machine may be allowed to run alone. It may happen that the Holtz machine ret ains its charge from the last time it was used, and in that case it is not necessary to give the preliminary turns to the \\imshursi or Toopler machine. If the Holtz machine refuses to produce a discharge in Inn or damp weather, the difficulty may often be overcome by disconnecting the machine from the ground or from the platform- in other words, removing any means of conducting away the discharge. The maximum efficiency of an influence machine can never be obtained without a certain external resistance, and this is most effectively provided by making it necessary for the discharge to take place across an air-gap. \\ith the discharging rods together, of course, there is no external resistance at all. and with the patient directly or indirectly connected with the machine, the electricity finds so ready an escape by (-(induction and convection that the external resistance becomes very much less than it would be if a charge could escape only from the bare discharging rods separated bv an air-gap. If. then, the connections are all made for the treatment of a patient and the apparatus refuses to develop a charge, the difficulty may often be overcome by disconnecting the conductors leading from the static machine, and separating the discharging rods about an inch. The necessity for a, sufficient external rc.-istance in order to obtain the maximum discharge H the reason that spark-gaps often have to be placed in the circuit with an .r-ray tube excited by a static machine. Accessory Apparatus for Treatment by Static Electricity. insulated platform should be of wood, measuring about t\vo by feet, and with glass legs about nine inches high, which should be free from dust and moisture, either of which would reduce insulating qualities. The platform should not be in contact with other object, and not near enough to anything else to lose part 42 MEDICAL ELECTRICITY AND ROXTdEX RAYS electric- charge by convection or a brush discharge to neighboring objects. A connection is generally made from one pole of a static machine by means of a xhcphcrd'* crook, a brass rod five feet long, which hooks over a prime conductor and rests upon the platform. A square piece of sheet metal an eighth of an inch thick lies upon the platform, and the shepherd's crook may rest upon this or upon the wood, at a variable distance from the patient's chair (Fig. 31). One leg of the chair mav rest upon the metal, or they may all be at a varia- ble distance from the metal plate. Then, again, the patient's feet may rest upon the wooden platform at a variable distance from the metal plate, or they may rest upon, the latter. These different combinations regulate t he strengt h of a charge received by the patient seated upon the platform, by varying the resistance through which the charge must pass to reach him The cnnrit i- a ring of brass about eleven inches in diameter, with a series of points projecting downward. It is extended above the patient's head bv a brass rod attached to the woodwork of the top of the case of the machine, and its height is adjustable. It may be connected with the pole which is not connected with the insulated platform, or it may be grounded. Brass chains are used for making and various other connections between the static machine and cces.si iry apparatus. I >ircrt method. I.' i
  • ; a -eparato rod: or some machines are so constructed thai 'hi- rod i- mounted under the shelf in the form of a lever. When this Cement ;- il~ed, there is a label marked "sparks" so placed that the handle i.- in a line with it. the rod underneath connects the out-ide coatings of the two jars. If the I.eyden jar spark is not STATIC ELECTRICITY desired, it is always best to remove the Leyden jars from connection with the pole pieces of the static. This is advisable for two reasons: first, that when they are connected, even though the outside coatings are not connected, still the Leyden jars impart a sharp quality to the current administered to the patient, which is usually very un- desirable; second, when the jars are left in connection, it is pos- sible that, inadvertently, they may become connected so that the carbon point: .">, bra>s point: t>, brus> ball; 7, bra-.s bru>h; S, chain-holder; '., cord-, liim- paliont would receive the discharge from the two jars, which would give a. very violent, shock. As this is absolutely avoided by ha\ in<: the jars removed, it is to be recommended. A N< / of ( h'ctradcs (Fig. o-1 have insulated wooden or hard-rubber handles, and a metal ring for the attachment ot a chain conduct the charge to or from the electrode. These electrodes tern nate different ways -one has a metal point, am a her has about - 1 ' p: pointed brass rods; another has a gas-carbon extremity : another 44 MEDICAL ELECTRICITY AND RONTGEN RAYS a two-inch brass ball: another a two-inch wooden ball; another has a brass roller. There are two sponge electrodes with heavily insulated handles and a pointed wooden electrode. A chain /tuldi r with an insulated handle is of brass, in which a single open turn has been made, so that it can easily be hooked around the chain leading to the electrode. It enables the operator to keep the chain from contact with the patient or any other object, and so prevents shock or loss of electricity. A c is a brass rod mounted on a metal tripod, and so arranged that its pointed extremity may be directed toward any part of the patient. A chain leads to it from one pole of the machine or froin the ground. ( >ne way of measuring the voltage of a static machine is by noting the length of a -park which will pass between the discharging rods while the machine is not connected with any other object. The distance across which a spark or disruptive discharge will take place rhroutih the air depends on the voltage or electric tension, and also upon the nature of the discharging surfaces. A spark S mm., or of an inch, long between polished metal balls o cm., or 'iie-<|iiarter inches in diameter, represents a tension of about ills. Other estimates covering a variety of conditions vary nix) to :;.">. i mo volts per inch of spark length. This has reference to the -park which passes completely across with a clear ud sound, and not to the brush discharge, which is seen when the poles are very far apart, and which is visible as a complete bridge over the u'ap only when the room is darkened. Without the I.eyden jars there is perhaps not a very .-harp line in t he case of static elec- tricity between the true disruptive discharge and the convective dis- charge, but with the Leyden jars and a rod connecting their outer coat-, there is no mistaking the disruptive discharge or true sparks for anything else. However, it is the discharge from the bare poles which it is important to measure, and which indicates the voltage or 1 he difference in potential between 1 he poles. The volt age produced by a static machine can never greatly exceed that represented by a spark-gap of half the diameter ot the revolving plates, or the distance bet ween t lie nearest charged met al- lic parts usually the discharging I'his i- especially true of small machines having \ machine \vas exhibited in Washington which L r la-- plates, thirty-two inches in diameter. !re ; and !;;iv revolutions a minute, developing nchc- lonsi. In the winter time we frequently STATIC ELKCTRICITY -t.~i have machines having ten or twelve revolving glass plates thirty-1\vo inches in diameter, that will give a spark seventeen to seventeen and one-half inches long. More than that, the statement refers only to the Holt/ type of machine. The Toepler-IIolt/ type, which is' the type used by the mica plate. Bet/, and other Chicago manufacturer-, will, as a rule, develop a spark one-third the diameter of the revolvinu plate. No matter how efficient a static machine may he, the voltage is limited as above, just as the pressure in a steam-boiler is limited by the safety-valve. The hottest fire cannot produce a threat er pressure than is required to raise the safety-valve. With the static machine, if there is a tendency to produce a higher voltage or pressure, the resistance of the intervening air-gap is overcome, and ;t discharge takes place, limiting the voltage to the specified amount. In applying electricity produced by a static machine the voltage can be regulated by the speed at which the revolving plates are rotated. The Tension of Static Machines. The discharging distance between two metallic spheres 1 cm. in diameter is different for varying tension-. DISTANT!-: OK THK T\vo SPHEKES. C'EXTIMKTKKS. l\cm-:s. 0.1 0.5 .0 The above table is compiled from Joubert's "Train'' d'Klec'trieitt'." When one pole of a static machine is grounded and the other insulated, the potential of the latter rises to twice the figure it ha>i when both poles were insulated. The pole that is grounded has a potential of zero, and the other has its potential doubled, so that the original difference in potential is maintained. The Efficiency of Static Machines. A test of a Holiz machine has been made by Professor Samuel Sheldon, of Brooklyn. New ^ in which the efficiency was shown to be more than MO per cent. static machine was run by a one-quarter horse-power electric m so that the power applied was accurately known. The poles of this static machine were connected with the poles of another static machine which was not provided with a motor. '1 lie discharge oi static elec- tricity through the second static machine caused its glass plates to revolve rapidly in a con.1 rary direction, and the power thus generated was measured by means of the brake resistance which it would over- c< mie. The Output of Static Machines. The output of a static machine is the quantity of electricity which the sparks carry across between the two balls in a second. It varies according to the efficiency oi the machine, between ,.-,!.., and ,.1,-, or more of a coulomb. This is equiva- lent to a current of from ,',, to 1 or more milliamperes. iMtic's hottlr for measuring the output of a static machine give- the output in microcoulombs per second, which is equal to milhan. peres. The calculation is based upon the capacity (' in microfarad- 40 MEDICAL ELECTRICITY AND RONTGEN RAYS of the Levden jar (Lane's bottle\ the potential V in volts required to -park across the air-gap of the Lane's bottle, and X, the number of -parks per second. The output 1) in microcoulombs per second is given by the formula - D = NVC. The distinction between quantity and potential or voltage 1 is illustrated by the steam engine. In the boiler the pressure is so many pounds to t he si | u are inch, wit limn reference to t he size of the boiler or t he amount of water converted into steam in a certain time; the last two elements, without regard to pressure, convey the idea of quantity. A static machine with sixteen revolving plates will generate a much greater of electricity than one with only four revolving plates, and so achine revolving at a higher rate of speed than another, but if 's are of the same diameter and the construction and insulation llv perfect, the voltage produced will be the same. A machine with a greater number of plates and a more rapid rate of revolution will produce a better effect by maintaining a more constant supply of elect rich v at a cert ain potential, making up in this way for the constant losses 1>\ convection and conduction. The quantity of static electricity in a charged bodv may be measured by the repulsion it produces upon a similarlv charged body, or its attraction for one oppositely charged. The force exerted varies directly as the charge and inversely as the square of the distance, but the latter fact is mly exactly true between points and not between extensive surfaces. Coulomb's torsion balance (Fig. oT) consists of a glass case containing two metallic squares, one fixed and one fastened to a rod suspended horizontally by a wire; both metal squares are similarly and equally charged, and the insulated handle at the top of the suspension wire must be turned a certain distance in a direction op- posed to the force of repulsion in order to bring the horizontal rod into the standard position. From the amount of torsion or twisting of the wire can be calculated t he amount o| elect ricit y. 1 he tfutiilnifit < /< rl rnnn t< r is so called because the re are quadrants or quart ers of a circle. These deflect an a I -uspended by a line wire, and the degree of deflection i.- a mirror observed through a telescope. e m measuring the dosage of static electricity a piece of sheet n inch -'qiuire is applied to a given part of the patient by in-ulated handle. h receives a charge proportional to I he charge at that part of the patient, and tins is carried o-- a- possible to I he electrometer. The carrier is placed projecting trom the top of a gla.-s case, and coin- mean- ill a metal rod with the electrometer vanes inside Arrangement of Static Machines. F w th STATK KLKCTHICITY 17 48 MEDICAL ELECTRICITY AND R()NT(;EN RAYS illustrated a brass chain is seen hanging from the connecting rod and extends to earth connection. The two discharging rods of the static machine are separated by about nine inches, and the sparks (Fig. 36) were passing across at the rate of about two a second. The picture was taken with an exposure of fifteen seconds, and shows the path of all thes<> different sparks. It will be noted that the sparks from the positive pole start off practically in a single straight line, and become divergent at a distance of about an inch from the terminal, so that thi- picture of a number of successive sparks reproduces the familiar fox-tail appearance of the brush discharge, which takes place from the po>itive terminal when the Leyden jars are not used. Even then, perhaps, the fox-tail appearance is due to a very rapid succession of single sparks following the paths indicated in the present picture. It looks, however, like a simultaneous group of sparks. The positive terminal shows a number of little green stars on the surface of the metal, and t he discharging spot may be displaced by a bit of wood like a match. The negative end of the succession of sparks shown in the picture leaves the terminal from quite a wide distribution, just as was the case in the negative breexe about the Leyden jars. The negative terminal shows a pure violet, with only one* 1 in a while a white spark right on the surface of tin- metal. At the lower left-hand corner of the picture are seen the two open dishes of pure calcium chlorid. Kach of these contains a pound, and the machine has never failed to work, winter or summer. The broad white sector is one of the field-plates on the foremost of the lows the distribution of a succession of sparks, the g the negative and the right the positive terminal The distance was six inches, and connected Leyden All the sparks are united in a single trunk at the ( ) SOME PRACTICAL ELECTRIC UNITS For electric measurements the fundamental units are the centimeter, for length, the t be discoverable by the ordinary means of chemic analysis. Nevertheless, as applied to machines having eight or more revolving plates, the polarity of the static current has a most decided effect in the treatment of certain forms of headache. One pole over the head v increase the headache, while reversing and putting the othr-r pole over the head will relieve the headache. In using static electricity lor ; 4 Ol) MEDICAL ELECTRICITY AND RONTGEN KAYS countorirritiint effect we always make the electrode negative, and the difference in the effect is easily noticed by the patient. "\Yhen the electrode is negative, it feels like a stream of fine sand striking against the skin, whereas when the electrode is positive, it feels like a cool bree/.e blowing. Another form of treatment in which the polar effect is most marked is what is known as the ire of static electricity, voltage is chiefly of importance in determining the distance across which a charge will lla-li in the open air. or the way in which it will pass through the partial vacuum of an .r-ray tube. In the case of the lesser voltage and vastly t er am per age oi dynamic electricity, volt age is chief I v of importance quantity of electricity which will pass through a having a cert am re! water from a force-pump washing out sand and gravel from a hillside by its mechanic force, but producing no appreciable action in dissaving the ingredients of the sand and gravel. The effect of great quantity, even if under small pressure, is exemplified by the caverns and pa2 MEDICAL ELECTRICITY AND ROXTGEN RAYS with which t ho solid rock in the Mammoth Cave of Kentucky has boon honeycombed by the- solvent action of water percolating through the ground. The condition of the opposite charges in a Levden jar or other con- denser is illustrated by that of water in a U-shaped tube. The water on either side is maintained at a hiirh level by the pressure of the other column of water, and both columns will remain quiescent and at an equal level until either a large or a small opening is made at the bottom, allowing both to escape from the tube and mingle in a single mass at the natural or neutral level. A Leyden jar so overcharged as spon- taneously to discharge is like such a U-shaped tube, in which water has been added to such a height that the walls of the tube have given away and the water has escaped, or a still better comparison is with two equal weights hung at a great height by a cord fastened over a pullev: either one can be moved up or down as if not possessing any weight at all as long as it is balanced by the other weight. The}' remain qiiie-cent until the cord breaks, and then both fall to the ground with a crash. A good though incomplete analogy with electricity may be seen in compression or exhaustion of air. Air in a closed container at the same pressure as the surrounding atmosphere is like the electricity in an insulated uncharged body. It exerts no force tending to break through the container: and if an opening be made in the container the condition becomes analogous with an uncharged and uninsulated body and the air does not pass through the opening either as a current or with a -udden rush. Pumpinir air into a closed container of a certain size with rigid walls and up to a certain pressure is analogous to charging a body of a certain capacity in microfarads with static electricity of a certain volt- age. The compressed air has a tendency to burst the container or rush through any larire opening made in it and immediately reduce the preure to that of the surrounding atmosphere. It has also a tendency to e-cape through any small openings and so to gradually equalize the pressure in-ide and out. In an analogous manner a charge of static electricity ha- a tendency to e-cape as a loud spark if a conductor is brought near it. or as a uradual leakage into the atmosphere from sharp point- or in consequence of imperfect insulation. A closed cylinder with an air -pace at each end. with a diaphragm in i he middle and a pump by mean- ot which air can be exhausted from one hall and forced into the other, i- comparable to the charging of the two pole- of a static machine with positive and negative electricity. And it we have a hole in the diaphragm with a pop-valve through which the air mav pa-- with a ru-h when the excess of pressure be- coine- -ufficieiii to overcome the resistance of the valve it is like the -park which pa-se- between the t Wo poles of the Malic machine. The excess of positive and negative charges neutralize each other t" -u<'h an extent a- to prevent the difference in voltage at the poles of the static machine from becoming greater than i- required to overcome the re-i~taiice (if i he -park u'ap between the discharging rods. In the illustration we have cho-en the air pump is supposed to be in contimiou- operation and to be of -ufhcient capacity to constantly nriintain the de-ired phi- and minu- pre--ure- in the cylinder in spite ot the tact that from the minu- outlet a suction apparatus such as a STATIC' ELECTRICITY vacuum cleaner may he used, or from the positive outlet compressed air may he used for a spray or atomizer. Or the two outlets might lead to some apparatus through which it was desired to have gaseous contents of the cylinder circulate, as in a machine for making artificial ice. a i' Fig. oS. a. Cylinder with control diaphragm and air pump to increase pressure in one half and reduce it in the other to illustrate electric voltage, h. Air pump exhausting at one side and compressing at the other to illustrate charging with electricity, c, Safely valve allowing escape of air under excessive pre>sure; to illustrate electric disruptive discharge. In a static machine the positive and negative poles correspond to the plus and minus outlets and the spark gap corresponds to the 1 pop-valve 1 in our compressed air illustration. Me)ne>pe>lar applications may he 1 made to the patient from either pole of the 1 static mae-hine, such as spark e>r Morton's wave current. Or, as an example 1 of a hipolar application, the positive pole may he 1 eon- nee-te'el with an insulated platform upon whie-h the 1 patient is seated, and the 1 negative 1 with the 1 metal creiwn for a static head hreoze; the- electricity passes through a e-emtinuous circuit. This ine'ludes the air spae-e hotweem the 1 ore>wn and the 1 patient's, head; and also the 1 wood of the platform and chair hetween the positive 1 conducting rod and the patient. Both of these poe>r conductors act te> mexleM'ate the severity of the 1 application and make it very pleasant. A small ste>p-coe'k at each of the 1 emtlots fremi the air cylinele 1 ! 1 in our anale>gy woulel in the 1 same way limit the curre-nt of air from eMtheT outlet or through any e'hannel connecte-d with hoth. To se'ek an analogy for a condense 1 !' we might have 1 a cylinder with two compartments with as gtvat a minus pressure' in one as there is plus in the other. The' two outlets are' separated only hy a stop-cook, and opening this permit- air to rush through and the' pressure 1 to hecome 1 cejUalizeMl just as providing a conducting path hetween the two co; peTinits the electricity to he 1 discharuvd. Xo close analogy exists hy which we- can illustrate the force 1 <>t the 1 attraction which e'xi>ts hetwe'eMi the 1 opposite 1 charge's upon the two .')4 MKDICAI, KLKlTKICITY AND KOVTOK.N KAYS coatings of a condenser, enabling cadi to receive a larger amount of electricity than could he forced into it l>y a given pressure or voltage and making it impossible to discharge either unless the other is also discharged. The capacity of the condenser is analogous to the number of cubic inches of -pace in the air cylinders. The voltage to which it is charged is analogous to the number of pounds pressure to the square inch in the air cylinder. The quantity of electricity is not usually considered in the case of a condenser, but it would correspond to the quantity of air in the cylinder. This would be expressed in cubic feet i >f air at the ordinary atmospheric pressure; and in the case of elect ri city t he unit of quantity is the coulomb, which is a quantity capable ot producing a certain amount of electrolytic eftect. The quantity of air which a cylinder of a certain size will hold is directly proportional to the pressure, and that is also the case with a body charged with electricity. SOURCES OF HIGH ELECTROMOTIVE FORCE OR STATIC ELEC- TRICITY Natural Sources. /,/( H ).()()() oscillations a second. Its rending and heating effect- are well known. Its, effect upon human beings is de-cribed in aii"ther section of the book. Anunnl rifnf ///VWVX.-.TN all produce electric charges and currents, and in the c;isf of the torpedo linin tor />i ). electric ell ((/ifnin(itnx), and the electric ti-ii . Jui-ns 1 1, rlriru.- 1 , well-marked shocks can be given at will. I't'int I (t> i- accompanied by electric charges and currents. M i I'lui i, if toj-ces m nature, such a.- rain. wind, the splitting of rocksj or wood, produce electric charges. The surface of the earth normally is negatively charged as compared with the air. The charge, however, is very small, being for the whole surface of the earth only Jive times the amount of electricity carried by 1 LMain of hydrogen in electrolysis. There is normally a con-tant dis- charge from the -urface < ( f the earth to the air. \nruinl Jniiizntiini //////, .1/V Over tin l^irtli. -This amount- to the production of about ~2\ ion- per cubic centimeter of air per second. The pj-e-eiice of rad inn i in t he crii-t of the earl h has much to do wit h t he pheni imeni in. Ham carries \vith it to the earth an electric charge of greater or less magnitude which i- more frequently po-itive than negative. /.<;/// falling upon an in-ulated metallic body instantly gives it an < iect ric charge. Cfn/nir /,1'nri . . i . UK'/ ittii/Htfti* in nature produce electric charges a ii' 1 current -. STATIC ELECTRICITY O.) k Sound will produce electric charges both directly and indirect lv. An example of the latter is seen in the ordinary telephone. Artificial Sources, -i'ricthm: Accidental: Walking along the floor; combing one's hair. Purposeful: Rubbing amber, glass, hard rubber, sealing-wax, fur. wool or silk. Frictional electric machines. El< ctrostatic Induction: Holtx, Toepler, Wimshurst machines. Contact of dixxinular metals (migration of ions). Heat at junction of dissimilar metals and different points around the circumference 1 of a ring. Heating tourmalin. Electromagnetic induction. Chemic action in the voltaic cell. Other Mechanic Methods. Splitting a piece of mica. Pressuie upon a crystal of tourmalin. Percussion. Shaking mercury in a vacuum tube. Crystallization of substances from their solutions. Solid ifications of molten substances. Electricity a Universal Attribute of Mailer. All animate or inanimate matter is endowed with electricity, which requires only some exciting cause to make it manifest. THE PHYSICAL EFFECTS OF STATIC ELECTRICITY 1. A thoroughly insulated body charged with either positive or negative free electricity i. c., unbound by any inductive influence-- shows a repulsion of its component particles, which is most perceptible at its surface. In electrotherapeutics, for instance, the patient's hair may stand out in every direction from the head. It has an attraction for bodies oppositely charged or neutral. It produces or modifies static charges in neighboring bodies by induction. It does not undergo any perceptible change in weight or physical or chemic properties. J. A body which, like one coat of a Ley den jar. possesses a bound charge of electricity, exhibits none of the properties of a charged body except an attraction for the oppositely charged coat. o. A body from which free electricity is discharging undergoes extremely rapid and complex molecular, atomic, or subatomic changes. The discharge escapes either by convection, conduction, or as a spark or disruptive discharge. Particles of the body itself, even of solid metal, are torn away, and assist in carrying the electricity along the path of a disruptive discharge, and sometimes may be distinguished by the characteristic color which different metals give to the spark passing between them. The particles of metal are vaporized and rendered incandescent, and may be recognized by the spectroscope. The different appearances of the discharges from a positively and a nega- tively charged body have already been described ( p. 281. \\lien a body is discharged, the repulsion of its particles suddenly ceases, and loose but still attached parts of the body which have been spread wide apart by mutual repulsion will fall together. Among inanimate objects the best example of this is seen in the gold-leaf electroscope, aid in therapeutics the patient's hair is suddenly plastered down upon the head. The magnetic effect of discharges of static electricity is seen in the magnetization of steel needles, and again the polarity of a ship's rompa-- is sometimes changed in consequence of a lightning flash. Xo practical use is made of this effect of static elcctricitv. .">() MEDICAL KLKCTHICITY AND ROXTGEN HAYS A chemic change takes place in the charged body during a static discharge. This is sometimes more readily perceptible in the air or other medium through which a discharge takes place. Delicate tests for chemic change, however, show that changes occur even in a solid body when a discharge of electricity takes place from it. In Fig. 40 a celluloid photographic film wrapped in two thicknesses of light-proof paper wa< charged by attaching it to the negative pole of a static machine. The numerous small white spots show the effect of the convectivc discharge upon the sensitized surface, and the large white spot, the effect of the disruptive discharge which occurred when the other pole was brought near to it. As the film was wrapped in closely fittinu 1'mht-proof envelopes, it is probable that the effect was produced b a direct chemic action, and not indirectly by the light of the sparks. ischarge upon a photographic film in cemc efect- upon the head of I'hy-ioloiric Kf'fecH. Thf hentiiiu effect of the static discharge upon the charged body may be -hown by the !u-ion of a fine wire forming the discharging point "t a powerful bai I cry of Ley den jars or in t real ing a pat lent 1 he a lit hor ha- -onietinie- h;td thr point of one of his finger-nails scorched by the coiiveet ive di-charu'e. The fin tier in tin- case had been pointed ;it the patient, mid acted ;i- ;i concentrator, caiismu' the discharge to take place from thai particular part of the patient. ( ienerally -peaking, however, the hentuiL: effeci upon the discharging body it-elf i- very -liiiht. and -park- may be applied through the clothe- without danger ot injuring the fabric-. A -ucce--ion of short, powerful sparks applied STATIC ELECTRICITY O ( at one spot, of course, will set fire to anything, The heating effects of powerful discharges of static electricity are shown when a tiny black hole is burned in a sheet of paper held between the two discharging rods of it, static, machine, with Leyden jars connected for spark effect. It is also shown when a building is set on fire by lightning. Then, again, when a wooden clamp with some metallic parts is used for an .r-ray tube, a spark from one of the wires may set fire to the wood. Light is produced by static discharges, and is sometimes seen upon the charged bodies as a glow discharge or a silent or convective dis- charge of a violet color, and when this occurs from a single point, its shape is seen to vary with the polarity of the charged body. If this is negative, the glow has a globular appearance, as if the negative electricity were escaping into the air in all directions; and the glow discharge at a positively charged point has a branching or brush appear- ance, not deviating much more than 45 degrees from the direction in which the point projects. The glow discharge is not strictly an effect upon the discharging body, but upon the surrounding air. Solid particles in the air become charged bv contact with the charged body and are then repelled. This discharge 1 is seen as a violet light playing over the surface of the charged body when a concentrator of any kind is held in its neighborhood, but still not near enough to allow of a brush discharge or eifluve The difference between the two varieties is that the glow discharge is silent, continuous, and uniform, and is visible only close to the surface of a discharging body, while a brush discharge or eflluve can be seen in the dark to fill up the space between the dis- charging bodies with a violet light, and is accompanied by intermittent sparks or flashes or by sound. Both produce a breeze sensation upon the human body, and both will take place through the ordinary clothing. A static discharge produces magnetic and electromagnetic effect.': upon the discharging body, similar to those of dynamic electricitv but in such small amounts as not to be of any importance in thera- peutics. 4. The effect upon the air from a discharge of static electricity through it has been partly indicated in the previous pages. The chemic effect is of importance. A portion of the oxygen is changed into ozone, and another small part of the oxygen is made to combine with some of the nitrogen of the air. The odor that accompanies the discharge of static electricity is produced by a combination of these two newly formed compounds. On the assumption that the ozone is of the prin- cipal importance, inhalers have been made iFig. 41) in which a glass globe surrounds the spark gap and has two openings one tor the admission of air and the other loading to the patient's mouth and nostrils. Two glass vacuum electrodes form a spark-gap free ironi injurious metallic fumes. The nitric acid which results from a spark dis- charge through the air is not of much apparent value in therapeutics, but it is of tremendous practical importance in another way. All animal and most plant life requires nitrogen in an assimilable form, but neither of them can utilize the nitrogen so abundantly present in the atmosphere 1 . For all practical purposes the nitrogen is inert, and simply dilutes the oxygen which forms the most important part of the air as far as the daily life of plants and animals is concerned. Fven the nitrogen which i- al >sorb('d and held in solution bv rain-wat er and carried hit o t lie earl li i.- nm available fur the nourishment of plants or animals, \\here water power is abundant and cheap for the operation of dynamos, the high- MKDICAL KLECTHICITY AM) K< )NT( i KX HAYS ten-ion currents produced by transformers may be passed through an air-chamber. A multitude of points produce a great many separate -park paths, and a spray of water or of an alkaline solution absorbs tlie nitric acid. By this process ammonia or nitrates can be synthet- ically manufactured for fertilizers more cheaply than they can be obtained from natural sources. The static machine could be used in the -ame way, but it< output is much smaller compared with the amount of work required to operate it . Other Means of Obtaining Nitrates from Atmospheric Air. -The Hnhi r /Vorr.vx, Liquid air obtained by great pressure at a very low temperature is subjected to fractional distillation. This separates the nit rosjvu from the oxygen and other gases. Hydrogen obtained by elect roly/ing water is combined with the nitrogen, and by this means various fertilizers are manufactured. The cyanid proce-< i- not directly connected with electricity. It expose- calcium carbide to the nitrogen obtained by the fractional dis- tillation v -implv dropping a chain from it to the flour. Some prefer tn have a metal plate, which is connected by a wire tii a water-pipe or f the hou-e and connected with a lame metal plate placed I or ."j feet underground. STATK ' ELECTRICITY 01 Si/nopsis of Modcx of applying static electricity in medicine. 1 Conductive Disruptive Disruptive ( 'nnvective I r Ml Klectrostutir or franklinic bath. Concentric franklinization J ! ( Breitung system). t I 1 f I" I Static or franklinic autocondtic- tion. Static or franklinic autoconden- sation. f Morton's wave current or static or franklinic undulatory induc- tive i 1SS1) (liertzian franklini- zation). Morton's modified monopolar undulatory current (called also Snow's wave current). Derived franklinic or static induced current (Sheldon) or derived Morton wave current. ect ropositive. led roncgative lect ropositive. Icctronegative ranklinic or undulatory current, ranklinic or undulatory current. ndulatory current. ndulatory current. { Werber's modification of Moil on wave current ('H)O'J). Indirect franklinic or static dis- charges by means of a detona- tor, and of water contained in a bath-tub, in which the entire body is plunged (general hy- drofranklinixation). Sparks applied by means of electrodes of metal, wood, or hard rubber; spheric or pointed. Aigrettes. Static or franklinic discharges or through the intermediary in a tub. into which a hand, : hvdrot'ranklini/ation). { Applied at a certain from the body. ! Applied directly regions of the by the clothing I sage). distance on different >ody covered electric ma>- The sliding rods arc separated as far as possible. The strength of nil-rent can be increased by placing a metal plate on the platform and then placing the legs of the chair on this metal (Fig. 43). The current can be still further increased by placing the chair so that the patient can rest his feet on the metal plate. (See Fig. 44.) The only difference between the connections for static insulation 1 Slightly modified from Yirgilio Machado's table. Les applications directes de I'Electricite ;i la Medecine et a la C'hirurtrie. Lisbon, 190S. 1)2 MEDICAL ELECTRICITY AND RONTGEN KAYS and the Morton wave current is that the balls A and B are widely sepa- rated in static insulation, whereas in the wave current they are placed in contact to start with. The strength of the current used for static insulation is regulated mainly by the speed at which the machine is operating. This method of application is generally used when the case is hypersensitive to any form of electricity. It has a general quieting effect on the nerves, and is one of the best ways to begin static treatment, as by means of it you are sure to gain the patient's confi- 'JL r . -r.4. Lejzs of chair on metal plate. dence. It does not produce the slightest shock, and can be used in the most sensitive cases. The static bath is said to be electro-positive if the positive pole of the -tatic machine is connected with the insulated platform. The (i/>jilic(itieiim pushed under the machine. I lie smallest I.eyden jars, not much over an inch in diameter, are placed upon the little shelves, and their inner coats are connected with the prime conductors, In-ulated conducting cords are fastened to the two bindinii posts, and lead to electrodes applied to the patient. It is nut neeearv. but customary, for the patient to be upon an insulated platform mile-- there i- some contra-indication, like the simultaneous application of Mime other form of treatment, such as vibration. The machine -hould have been charged before the connections are made with STATIC ELECTRICITY u'ii the patient, and is now set in operation with the discharging rods in contact. These are carefully separated to an extent that is regulated by the sensation of the patient, but which will rarely be found to be greater than inch, or 3 millimeters. This separation should be made gradually, and care should be taken not to allow the discharging rods to get too far apart, either as they are being adjusted or afterward, from the motion or vibration of the whole machine. An arrangement is provided in some machines whereby a screw-thread on the discharging rods is brought into play to produce accurately graded motion of the rods as they are separated, and to hold them in that position. The electric currents sent through the patient in this way have been ex- plained elsewhere (page 29). Fig. 45 shows the smallest Ley den jar connected to one pole of the static machine, and connected with the outside of this jar is an ordi- 4"). Static induced. Fip. 46. Static induced, intensified. nary sponge electrode. The electrode is placed in position and the current regulated by slowly separating a and b. If a stronger current is desired, then two jars can be used as in Fig. 46, regulating in the same manner. The larger the jars used, the stronger will be the current with the same spark-gap. Here again, as in the wave current, it is essential to have a perfect contact between the electrodes and the patient, be used or two, as in Fig. 47, and any electrodes that is used with the gal- vanic or faradic current can be used with the static induced. As a rule, the smallest Leyden jars are used. A single electrode can , ground 4s. Morton wave current. Static Wave Currents. The Static Ware Current. This is also known as the conrcct/re discharge current, and sometimes as the vibratory C'irn nt or the Morton in ire current. In this method the metallic plate of tlie platform is connected to the positive pole of the static machine, the negative pole being grounded, the sliding rods in contact. The patient is placed on the platform, having the feet on the metallic plate Kiii. I'M. The strength of the current is now regulated by slowly sepa- MEDIC' AL ELECTRICITY AND RONTGEN RAYS rating a and h, and it is always well to withdraw the negative sliding rod. If the patients complain that they feel sparks on their feet, then remove the shot's, as this current should not be painful; if it is, it indicates a poor contact between the metal plate and the patient. The strength of this current is regulated by slowly separating a and b. There must be a continuous spark between a and b when this current is properly used. Instead of applying the current through the feet, as above described, any electrode that is used with the galvanic or faradic current can be used in place of the metal plate. This current is not pain- l'L r . i'.. X rri>rfsriH.- any electrode that can he used with galvanic or faradic current. fill, and should not lie used strong enough to produce any unpleasant effect upon the patient. Its main therapeutic value is due to the fact that it stimulates the glandular system to increased activity. It also has a local action in relieving the pain of sciatica. A modification (Fig. 49) consists in interposing a large Leyden jar between the ground connections and the negative pole of the machine. The advantage of this method will be appreciated during the summer month:-: when the connection is made 1 according to Fig. 40, it may only be possible to obtain a -park between ! shows a further modi- fication, consisting of an o/one u-eneralor in which the spark-gap takes place. ( 'onnected with the o/one generator is a tube, so that while the patient i< having the wave current he is also inhaling o/one at the same time. This make- a very successful treatment for chronic bronchial trouble-. STATIC ELECTRICITY When used for this purpose, instead of a being connected with the metal plate on the platform the patient has a large metal plate on the chest. This may be in the form of tin-foil, such as is used for pro- tection against the .r-ray, or it may be a large pad electrode which has been made thoroughly wet. Connected with the ozone generator is a piece of soft- rubber tubing having a mouth-piece, so that the patient inhales the ozon- ized air at the same time the wave current is being passed through the chest. This can be modified in a number of ways. Instead of using a wave current, the d'Arxoni'al high-frc- \ qucnctj current can be passed through the chest and the Tesla current applied to the ozone generator. In place of sup- plying ordinary atmospheric air to the generator, pure oxygen can be supplied, in which case the patient will inhale pure ozone. Again, the Fiji. 51. Wave current and o/nn vacuum electrode; other pole grounded Wave current applied by vacu- um tube. ozonized air can be compressed and used to operate a nebulizing device, in which case various medicated oils are used. Fig. 52 shows one way of using the ordinary vacuum tube with the static machine. The current is really nothing but the wave current ap- plied through a vacuum electrode. The strength of the current is regulated by separating a and /;. Fig. 53 shows another way of using the vacuum electrode, which consists of grounding the negative pole and at- taching the vacuum electrode 1 to the positive pole. This makes the current stronger. Fig. 54 shows similar arrangement with a Leyden jar which is suspended from the negative pole and which has its external armature grounded. While the current passing through the vacuum tube causes a violet color, this is not what is understood as high-frequency current or as the ultraviolet ray. The Electric Connection for the Static Induced Current and the Slaf;c Ware Current. The different contacts past which the discharge has to OO MEDICAL ELECTRICITY AND RONTGEN KAYS flow to the patient should be perfect. The Leyden jars may generally be hunt: upon the brass rods and produce a good enough contact by their weight: but the terminals of the conduct ing cords had better be secured by thumb-screws instead of being simply slipped into the bind- ing-posts. Then, again, the fastening of the conducting cords to the electrodes should be by means of a thumb-screw or pressing the terminal of the cord into a spring slot, not merely by twisting it around some part of the electrode. The two terminals of the conducting cord, if they are, as usual, separate piece- of metal, should be soldered to the end of the wire. Simply twisting the win 1 about the metal terminal will not do so well. At all these points of contact particles of dust between the metallic surfaces or a film of metallic oxid upon one or both surfaces will make the contact imperfect and prevent the flow of a uniform current. The electrodes themselves should be considered. The ordinary sponge electrode usually has a perfect metallic connection from the conducting cord to the metallic surface, over which the damp sponge is stretched. At this point, however, an imperfection often develops in the shape of a layer of verdigris or other metallic salt upon the surface covered by the sponge. This interferes very much with the flow of the current. The result of an imperfect connection at any point is to increase enormously the resistance to the flow of the current, and consequently to make the current much weaker. Then every little while the current finds an un- obstructed path and a strong current flows for an instant, to be again reduced as the oxid re-forms. The result is a series of disagreeable jerks of the different muscles of the part of the body to which the current is applied. Block-tin Electrodes. Pure tin is as flexible as sheet lead and does not rub off on the skin and clothes. Pieces of appropriate size are preferable to wet electrodes for many static applicatkms. Static Spark and Breeze Applications. With the same connections the patient will receive a spark from a metal ball electrode and a breeze or eflluve or spray from a pointed one. A shepherd's crook conducts the electric charge from one prime conductor of the static machine to the insulated platform upon which the patient sits; while a chain conducts the charge from the other terminal to the crown or some other effluve if a breeze is to be applied or to a ball electrode for applying sparks; or. the other prime conductor may be grounded, and indirect sparks may be drawn from any portion of the patient by bringing a grounded ball electrode near the surface. Another form of indirect spark is applied to the patient seated upon an insulated platform, connected with one prime >r. while the electrode connected with the other prime conductor no to the surface of the patient, but to a metal plate, rod, -e contact wilh the surface. The effect from this form of )f the static induced current or the wave '- . -The patient is seated upon the insulated epherd's crook conducts the charge from the ie. The negative pole is grounded and For the overhead indirect breeze, for n the standard and raised above the STATIC ELECTRICITY 67 roller electrode is used and pressed firmly against the clothing of the patient. This is a very severe method of treatment. y Fig. 55. Indirect method, head breeze. ITU Fig. 56. Direct method of applying static breeze or spark. Fig. 57. Direct head breeze. Jndirccl Spark FAcclrodc. Fiji. 5S illustrates a method of directing the static >park to any ])articular part. It consists simply of two brass balls joined together by a brass rod and held by a piece of hard rubber (is MEDICAL ELECTRICITY AND KONTCEN KAYS at an adjustable distance from tlic metallic part of the electrode handle. The terminal brass hall is pressed firmly against the part of the body to which it is < le.-ired to direct t lie spark. A cont iniious series of sparks may lie applied by connecting the metallic part of the electrode handle with one pole of the static machine. Or separate sparks may he applied, by approaching a ball-electrode from the static machine and allowing a spark to pass from it to t he metallic part of t he elect rode handle and thence to the terminal hall and the patient. l)irtd ]>/'<< :c Aj>i>liaiti(i. r rh( i connections are the same as for the direct spark, hut the electrode is a pointed one. and may consist of metal or carbon for the stronger or of wood for the weaker effects. The direct head bree/.e is one of the most useful of these applications. The crown is at a considerable distance from the patient's head to avoid uncom- fortable prickling. The current will be in the form of a spark if a metal ball electrode is used. Other electrodes intended for a bree/e or spray are illustrated on passes 44 and 45. The only difference in this method from the previous one is that an electrode is added, making a local ap- plication of the current instead of a general application. The chain to which the electrode is connected can be dropped on the floor or con- nected to the gas-pipe (Fig. 5',)). With thi- method any style of electrode may be used. In a general way the strength of the current is governed by the material of which the electrodes are made, wooden electrodes giving milder effects, pointed met;d electrodes giving a -tronuer effect, and, where a .-park is desired, the large brass h;dl i- usually used. This method is used for producing local action of the static current, a strong bree/e being used in the treatment of mild muscular pains, such a- come from catching cold. A static -park i- used up and down 1 he -pine in cases of loco mot or ataxia and for acute muscular pa in-. In acute muscular pa in it will give almost in-tant relief. < M course, the pain- come back again in the course of a few hour-, but can be ana in relieved and for a long time. It al-o con- siderably relieves the ataxic pain-. For administering the bree/e, Codes have been made of variou- material-, different kind- of wood varying in the current according to their resistance. There are -ome hollow electrodes m \\hich have been placed various kind- of liquids. fti'lin i 'I SjHirl: nml I'm < :> . The pat i cut is -eated upon 1 he in-ulated platform. lo which the -hepherd's crook conducts the charge from the positive pole of the static machine. The negative pole is grounded and STATIC ELECTRICITY the electrode is also grounded. For the overhead indirect bree/e, for instance, the crown is placed in the standard and raised at>ovc patient's head (Fig. 55). Fig. 00. A hollow wooden electrode filled with liquid for long spray. Figure 60 shows the use of a hollow wood electrode filled with water. This affords a means of applying a spray of long, thin, painless sparks. hole g/ass- Fig. 01. Spray director, a, can be moved to regulate distance between point and hole in glass. Figure 61 shows the author'.* indirect xpray electrode with regulator. Figure 62 shows the method of application. rig. Cii.'. Method of applying >prav director: S.il. i~ si>rav director t patient. Brass ball is connected to end of brass rod mounted on insul; [pointed end toward M pole of static. Strength of spray from director increa pt'inl approaches M pole ol static. (Original regulating de\ ice by authoi Production of <] A rsonral Current*. l^'iiiure (>! shows the ar for securing d'Arsonvul high-freiiuena/ current.* iVom a static ro MKDH'AL KLFA-TH1CITY AND KONTCKN RAYS N x. represent the sliding rods of a static machine; {/. represents a spark- u-ap' mounted in a box 'so as to obviate the noise; /, /, represent two Teyden jars; tt, represents a hard-rubber tube: r. represents two binding posts connected with the end of the coil, which connects the outside coatings of the l.eyden jars: h, represents the terminal of the line coil windmir. which is inside of the hard-rubber tube a. The above i< the outline construction of what is known as the I iffard huinrxlntic transformer. It differs from the transformer as made by Tesla in that in'place of the insulating tube a Tesla uses an insulating '. (53. Arniiiiirmi'iit for si-curint; d'Arsonval high-frequency currents from static oil, which was required owing to the extremely heavy currents that he used, whereas for medical work the oil insulation is not required. I)e Kraft's static inducto-resonator produces also high tension high- frequency currents and eilluves similar to those 1 from the Oudiu resonator. THE DOSAGE OF STATIC ELECTRICITY When the patient is upon the insulated platform, which is connected \vith one pole of the static machine, the surface of the body in general is uniformly charged with electricity. The density of the charge depends partlv upon the efficiency of the static machine and partly upon the completeness of t he in-ulat ion. The Franklin ha- been proposed by Benoist as a practical unit of den>it v ot the -t ;i t ic cha ruv. The C. G. S. unit of electricity is a quantity of electricity which, concent rat i ( 1 ;\\ -,\ distance ot 1 cent ii net er from an equal quantity of the same polarity, will repel it with a force equal to 1 dyne. The latter is about equal to 1 milligram. A coulomb is equal to i! x K)' 1 ( '. ( I. S. units, and i- a unit upon which the amperes and volts of electric current are based, but i- entirely too lar^e a unit to use with static electricity. The name Franklin is given to t he small ('. ( i. S. unit , and tin 4 dose of the -tat ic b;i t h i- expressed as I leum 1 ID Franklins when the den sit y meas- ured upon eit her -url'ace of the hand is equal to 10 Franklins per square cent imeti T. Benoist Electro-densimeter. This consists of a delicate elect ro- scope. which is cha rued by ;i n in-ulat ed di^k of appropriate si/e, which is applied to the pat ienl - hand and then to t he charging rod of t he electro- scope. I he graduation upon t he instrument should be such that tin 1 fiirure- indicate s,, many Fr.-mUin.- per -quare centimeter of the surface 1 tested. .STATIC ELECTRICITY / 1 PHYSIOLOGIC AND THERAPEUTIC EFFECTS OF STATIC ELECTRICITY The effects of its application to the huni;in body arc muscular con- traction, relaxation of muscular spasm, nerve stimulation or sedation, and similar effects upon glandular and circulatory functions and upon the intimate tissue processes, osmotic and others, of the body, and besides electrolysis and cataphoresis. A person connected with one pole of a static machine does not remain charged with electricity as long as the machine is in operation, unless the person is insulated. The whole current is unidirectional, and contact with the earth prevents its accumulation as an electric charge. The conditions are quite different from those prevailing with high-frequency discharges, which are oscillatory and keep the patient constantly charged with one or the other polarity. A person may be charged by induction from a static machine only if he is within a very few inches of it, but not if he is yards, or even miles, away, as with some high-frequency apparatus. The production of heat in the human body is increased during and for some time after a treatment by static electricity (Pisani and Mon- tuoro). chanyt'N and glandular secretions are increased. e effect x are obtained from a static bath or insulation, and from a static breeze applied exclusively to the part affected, as in neuralgia. Static baths are used, for instance, in neurasthenia, insomnia, and hysteria. Stimulative effects are obtained by the static breeze and sparks, and the patients are generally benefited by the static bath in addition. Cases of hysteric neurasthenia and muscular weakness from rheumatism or diabetes are examples. Physiologic Effects of Static Electricity. Adopting Machado's classification (page 410) the effects of static electricity may be grouped as follows: (i( n< /'nl stimulation, produced especially by local or general disruptive discharges. Motor stimulation, produced by local disruptive discharges and the various wave currents. It is not so characteristic of static as of galvanic or I'aradic electricity, and the 1 great majority of static applications are not accompanied by muscular contraction. Static sparks produce con- traction of the voluntary muscles, and will do so even in some cases where other forms of electricity fail to act. During a treatment by static elect ricity the myograph shows t hat the muscles are able to resist fatigue longer than usual (('aprioti, Pisani, and Schnyderi. Static electricity stimulates the growth of young animals (Capriati's experiments on tadpoles and Piccinino's on silkworms. The latter UTOW faster and better when exposed to static electricity than under the influence of high frequency and autoconduction). Xrnsorii stimulation, producing the sensations of taste, smell, siirht. touch, and hearing. Static sparks are not. however. >o effective upon sensory nerves as high-frequency sparks. The static breeze applied to the head often flattens the hair down on the head and causes prickling. which may be intolerable if the current is too strong. Revulsive ami // . a secondary effect of static sparks. Locally, there 72 MKDIC.VL KI.KCTKlcrrY AM) KONTUKN HAYS is nallor followed by redness. Static applications. general or local, do not have a very marked effect upon the circulation in health, but they of. en produce a favorable effect in morbid conditions with excited action and elevated or depressed arterial tension. h'< xuln'inj ii/nl st!tnvlatin*<>rj>lion of ('.ruddle* are effects produced by static sparks and the different wave currents. K.rcito/tiitritn't ami f tin natural incanx of defense of the organism is produced by the same conductive and convective applications. Slatir< ifhcf*. local or general. are obtained from a static bath or insulation and from a static bree/e or effluve applied directly to the affected part. The wave currents also have this property. The hy inutile effects of static electricity, or rather its effect upon the causes of insomnia, are produced by static insulation with a head- bree/e. But excessive or too prolonged stimulation of muscular con- traction by the wave currents will cause insomnia. ('and ri-,ation. Seated upon an insulated platform and holding the index-finger toward the crown furnishing the head-breeze, a short spray of violet light, hardly more than a bright point, may be seen to emanate from the tip of the finger-nail. The author has allowed this to continue for a minute or two and has found the finger-nail burnt or charred. AA'hile he has never heard of a patient's clothing taking fire from a static application, it has always been a matter of wonder to him that powerful sparks applied through delicate fabrics do not set fire to them: and lie always hold- himself in readiness to turn off the electricity and clap his hand over the ignited part if such an event should take place. The same -park- pa ed throuuh a sheet of writing-paper produce perfora- tion-. which may be seen if the paper is held up to a bright light. The inter-tice- in ordinary fabrics, however, probably allow of the passage of the static -park- without any effect on the cloth. Therapeutic Indications of Static Electricity. A study of the phy-ioloiiic effects and the forms of static electricity employed to pro- duce them, will at once suggest a wide range of general and local morbid conditions in which thi- treatment will be beneficial. I 1 or a coiinterirrilant effect from the static bree/e the electrode is negative and the -en-ation is as of fine -and striking the surface. AVith t lie positive pole it would feel like a cool bree/e, which is not so effective. liisinttHifi is best treated by static insulation with the head bree/e. Static electricity in nervous diseases is grouped with electrical application^ in a -cparate chapter upon electricity in diseases of the nervous system. 'I he following paragraphs are based upon Machado's classification: A- a i/i n( nil xti m nl ti nt -tat ic elect ri< -it y is invaluable in cases of debil- |>ro-t rat ing illne-s. or prolonged work and anxiety, as nd death o| some clo-e relative. The author employs with :i neu'a 1 1\ ( he: id- bree/e for about fit t ecu miniit es. l 10 1 11 |_> -park- a Ion <:' t he -pine from a metal ball. The the author STATIC ELECTRICITY I > has known of several remarkable cures in which the psychic element may have been predominant . Static baths or insulation are valuable as a systemic treatment in pruritus and ec/ema. Static baths or insulation are useful in neurasthenic patients \vith obesity. The excitomotor effect of the disruptive discharges and of the different \\ave currents may be an element in the benefit from the latter in the treatment of prostatic hypertrophy and chronic inflammatory uterine and other pelvic conditions. Cases of chronic constipation are sometimes benefited by static sparks applied to the iliac regions. Muscular contractions as a separate effect, either diagnostic or thera- peutic, are more often secured by galvanic or faradic currents with or without condensers. The excitomotor effect of the static wave current applied over the suprapubic region is useful for incontinence of urine due to insufficient control of the sphincters. Static sparks and effluves benefit atony of the unstriped muscle of the intestinal wall and pelvic viscera. The revulsive, derivative, and counter irritant effects of the static sparks are employed in the treatment of acute muscular pain, which is often relieved at once, and on its recurrence may be relieved again for a longer time. The lightning pains of locomotor ataxia may also be considerably relieved. Chronic painful articular conditions from gout, rheumatism, and gonorrheal arthritis have been treated by static sparks, but the patients often complain and the author does not employ this method to any extent. Friction sparks from a roller electrode or from a ball electrode rubbed quickly over the surface outside of the clothes is an effective 1 but very severe treatment for acute cases of stiff-neck and other painful muscular inflammations. Static sparks along the spine are of benefit in locomotor ataxia and for acute muscular pains and are a splendid general tonic. This action explains the benefit from static induced currents in tie fraitntent of furuncles. The external armature of one Leyden jar of the static machine is grounded, while a wire from the other leads to a con- denser electrode 1 which is applied to the surface of the boil. This elec- trode may be made 1 extemporarily by stuffing a glass test-tube with tin- foil. The effect may be to prevent suppuration, just as chemical coun- terirritants will often do, or, if pus is already present, the application will often relieve the inflammatory symptoms and favor evacuation. The xtat/e breeze is of service in ert/st})elax, suppurating wounds and contusions, and ecchynwses. The static breexe is also an excellent ap- plication in x/,'/// dixciisf x of a neurotic origin, and in pruritus vulva-. It is of service in xynuritix. the patient being in negative insulation. the- positive pole of the machine grounded, and a wood electrode or an ordi- nary whisk-broom grounded separately. It is excellent in mild mus- cular pains such as from catching cold. JIcr/H* zoxtrr is treated by light and static resonator effluve or the pencil brush discharge. 1 Lucy ( )sborn 'U'ight had a case of herpes /oster made worse by light and the static brush discharge. Titus finds that the brush discharge for the acute 1 .-tage dries up vesicles and relieves pain." (4 MKDICAL KI.KiTKICITY AM) KO\T(,KX HAYS II< iii/iii'hf i< often relieved hy static in-ulat inn and the head breeze. M. I.. II. A riu ild Snow reports the cure of sprained ankle in three treat- ment-: with tin' static wave current which acts by removing' exudation fn >\\i t he Ivinph spaces. 1 Overstretched font structures with exudate in the plantar fascia i- treated l.y radiant linht and heal and static wave current there, fol- lowed I >v -tatic -park- to mu-cle uroiip- in .-pa-m.- !',,, Micra-ili'ac xnliln.rfilinn IVckham and Snow advise radiant light and heat with static wave currents and sparks over the affected joint and muscles, and. at (mine, opisthotonos exercise. Tin Static \\~ J J n>tlnc(.' Muscular Contraction 'ui Muscular .!'///<*//,/,* ami StijJ Joints (Herbert V . Pitcher '. It is beneficial for the adhe.-iniis persistent in cases of tntich foot after the pain ha- disappeared/ 1 The static wave current and static sparks are regarded by Snow 1 a- the only mean- for removing the induration in traumatic arthritis and may prevent the development of chronic synovitis. Pressure infiltration with pain and tenderness of tissue is relieved by statir in- >dalit ie-. The ri'-'iL^ri and dcricativc effect of the static wave currents with a moderate excitninotor effect are applied through a vaginal or a rectal electrode in pelvic disorders characterized by hyperemia. Such condi- tion- are -alpiimiti- without suppuration, subinvolution. endometritis, dysmenorrhea. retroversion due to enlargement of the uterus, and de- layed men-i ruat i< m. 1 ' Synovilis i- treated by the positive wave current, applied for twenty minutes from a lariie metal or kaolin electrode accurately iit- t inu' t he ji lint ! lumphi'is . Static I'*liclricit;i in Circulator]! Disora'crx. There is often an effect upnii i he circulation, ;.nd Luxenbei'ii'ei" has noted a sedative effect in patients wiili heart disease frmn a series of static treatments, and has al-o seen the ce-.-ation <>\ mitral murmur.- of spasmodic origin if the static bree/e i- applied to the precordia for ten minutes. Arterial hyper- t en-ion i- freijueutly reduced l.u/enberger ). and static electricity is also an excellent aj) :. tnr arterial hypotension. My own ob-ervat ion- -how t hat for conditions <>f low ailei'ial ten -ion and lei-bl" heart the iie-t applical inii< ai'e t ho-e ill which the patient recei\ - a di-i'iipt ive di-chai'iie. or one through the air. -park.-, and And t<>r hiti'h artei'ial ten-ion, the application- in which the ; n lil'ectly connected with both pole- of the static machine are indj.-at"d. although not as effective as high-fVe(|Uency cur- i io i i- alone to be combated. nd fd/nc eliects are made 11-1- of in rilahi'tcx. wondert'nllv '.rood, and in a.valii/'ia and uric- "ii.'jv. vol. \.\xvi. No. :;. March Mils. p. U7. l'::!i\ ;ilii| lilidii iloilV. Vol. XXXVI. NO. 1, ' . I. .Io ... i \ .. . J.i. I'.tD.'i STATIC KLKCTKICITV , O ac'demia. Cases of deficient glandular secretion are benefited. >uch as hypochlorhydria and anachlorhydria and deficient intestinal secretion. The best method is to apply the static bree/e or brush discharge over the abdomen without sparks. Slulic \\'ore for Diabetes. Tills is recommended by AN". A.AN'hite. 1 but not in case of malignant disease or abscess. The pat ient is on an insulated platform, the negative pole is grounded, the positive being connected with a block tin electrode (22 gago thor- oughly wet. 4x7 inches. Liver and pancreas arc treated alternately. At first a short gap; later 3 to 7 inches, according to tolerance. Two hundred to five hundred revolutions per minute for twenty to thirty minutes. F. ])c Kraft'.* Treatment of Diabeff*. Increase muscle juices and the final oxidation of glycogon in the cells. Kesonator effluve from static machine is applied by bipolar method. Long narrow electrode over spine from the Tesla of static resonator, and ring effluve all over body near enough to cause slight muscular twitching. After that a metal plate from the Tesla is applied to the abdomen and effluve to spinal centers and spinal nerves. The sinusoidal current applied to the muscles of the abdomen and back would probably fulfil the same indications.' 2 Snow treat es diabetes with high blood-pressure by autocondensa- tion and the static wave current to the liver and pancreas. For purely toxic cases with gastric derangements and vertigo at start he uses t hi- st at ic wave current and the .r-ray. :! In hypcrtrophic cirrhosis of the liver, with that organ extending far down into the abdomen, the static wave current from Hat metal electrode is reported by Snow to cause contraction to normal limits and restoration of function.' 1 Autointoxication, also obesity, with low output of urinary solids, are benefited by static wave current (Fred. De Kraft, I. c, page '2^'.>i. Cciitioti: Don't use the wave current with too long a spark about the face in arteriosclerosis: violent shaking of the head might cause ntinal hemorrhage. For diabetes the static inducto-resonator effluve is ap- plied, first, plate to abdomen and efh'uve to spine; then plate to spine and effluve all over the body, moved quickly, causing muscular contiac- tion and profuse perspiration. Inducto-rexonator Actmiteil li Static Machine. Designed by Dr. De Kraft . it gives I VArsonval. Tesla. and ( hid in currents with somewhat different properties from those obtained from apparatus actuated by an induction coil or a transformer. D'Arsonval autocondensat ion from the static inducto-resonator is reported by Pitcher to stimulate faulty metabolism, reduce high blood-pressure from overeating <>\ i drinking, to be useful in obesity, nervousness, insomnia, rheumatism, and gout. Bipolar D'Arsonva! current static inducto-resonator is considered by Pitcher as one of the most satisfactory methods of treatment in chronic art hrit i- and synovit is. Uudin current or resonator eilluve (Pitcher! from static indudo- it) MKIUCAL KLKCTKK1TY AM) KoNTCKN KAYS resonator is a condenser discharge of very high potential. It produces muscular contractions with deep penetration, the rate of contraction bi-inir varied bv slowing or increasing the speed of the static machine, and the intensity or depth of the -park gap. A desirable teclmic is for the patient to sit on a plain chair upon an insulated platform, while a grounded metal plate from the negative side of the Tesla makes good contact over the abdomen, back, or at the feet. An insulated cord from the top of the < Midin solenoid extends to any suitable electrode, with an insulated handle. Such an electrode may be a metal ring, and if this is held near enough to the back opposite the metal plate which is over the abdomen good, strong, deep contractions are produced which are beneficial in functional disorders of the stomach and colon. 1 The metal ring is moved up and down the spine until there is decided hy- peremia. This benefits tender spinal nerves or spinal irritation. The eliiuve from the metal ring benefits bronchitis, asthma, and tonsillitis. An active hyperemia of the neck, chest, and back is produced. In many cases acute bronchitis can be aborted. Chronic neuritis and muscular rheumatism are benefited. The inducto-resonator eflluve produces intense hyperemia with local diaphoresis when applied to old joint conditions and vascular diaphoresis when over a greater area or entire body. The latter makes it valuable in arterial hypertension due to suppressed elimination from almost any of the usual causes. - The bipolar static inducto-resonator effluve is a desirable treatment for paraly/ed and atrophied muscles from war injuries; also regular indirect (not resonaton static sparks for pressure ulcer and pressure paralysi< ( W. B. Snow 1 . For diabetic gangrene William Martin uses the resonator eflluve.-' 1 I.o\v blood-pressure dependent on toxic conditions, also relaxed con- dition of veins, especially of lower extremities, are benefited by bipolar Malic inducto-resonator eflluve.' i!ln ni/idtniil urll/rilix treated by static electricity: the wave current may be applied, and the machine should be powerful enough to give a -park-gap with an electrode of b">0 or 200 square centimeters, require the static indirect spark: negative insulation, sparks - long drawn from the patient's body by a grounded elec- trode, the poles of the static machine far apart. If the sparks are too ndirect bree/e may be applied or a wooden ball not too dry at ion is to be preferred where there is boggy swelling ii pane 111), and diathermy by high-frequency currents STATIC KLKCTKICiTV , , Chronic bronchiai troubles are effectively treated by static wave curre-uts combined with o/one inhalations. LunilxK/o is tre-ate-el by the aj)])licat ion of a 500 ('. P. incandescent lani]> for fifte-e-n minutes; then the static wave- current for the same length of time with electrodes 8 x 10 inche-s, and the- spark-gap increased to tolerane'e- j>e-rha])s 8 e>r 10 iiie-he-s (Humphris). Sciatica. Finel the- small af'fecte-el a re -a by a])]>lying short sparks along the- e-ourse of the- nerve-. A flexible metal positive electrode, a lit tie large-r tiian this area, is bandage-el firmly. The ne-gaf ive- pole is gremnded and the spark-gap opcncel gradually, because the- application is painful at first. This is an application of the- static wave- current. Long-standing case's re-r four tivatme'iits combine 1 the 1 static c-lee-tricity with 500 C. P. incandescent lamp (Ilum- phris). (ionorrheal Itheuma/ixm Treated bi/ the Static Wave Current Applied to the Proxtdie. Titus applies the vacuum electrode connected with one- pole- of a static machine- to the 1 region of the prostate. This is on the 1 theory that the- gonococci are loe-ate-d in the prostate, anel not in the joints, and that they are weakene-el anel evae-uateel with the- urine- in consexiue-ne-e- of the contractions of the prostate 1 caused by the- electric applications. The-re are 1 cases, however, where the 1 gonococci are abundantly pres- ent in the 1 pus which fills the joint, and where- surgical evacuation anel disinfection are 1 requiivel. The 1 use of bactericidc applications to the eleep urethra is the other alte-rnative- whe-n the germs have 1 nett migrateel to the articulations and the- joint troubles are elue only to toxemic proelucts. The 1 application of the 1 static wave current for facial paralysis (p. 473) anel for tic eloulemreux (p. 50b'\ anel the Yates method e)f tivating ele-afness (p. 435) are elese'ribed elsewhere. DYNAMIC ELECTRICITY DYNAMIC electricity may !>c regarded a- electricity in motion, while static electricity is electricity at rest. Dynamic electricity is known chiefly by the effect of its transmission through conducting paths, and static electricity clnelly ly its effects as a stationary charge or as a disruptive discharge through non-conducting paths. NATURE OF DYNAMIC ELECTRICITY Klectricity of all kinds is probably of the same essential nature. Dynamic as well as static electricity may be assumed to be due to the application of forces which disintegrate the atoms of matter and liberate a iireater or less number ot ions about yoW the sixe of atoms. The positive ions liberated are ahvays equal in number to the negative ions. It is an interesting subject for speculation, whether perhaps the ions or the .-till smaller electrons are electricity and whether all matter is simply electricity under a variety of forms. By the application of some force. such as chemic affinity in the case of a zinc and a copper plate dipped into dilute sulphuric acid and connected by a wire outside of the liquid, a liberation of ions is supposed to take place. The force with which the positive and negative ions tend to pass, through the different media so as to neutralize each other is called the electromotive force, and is measured in volts. The natural and artificial sources of what is called dynamic elec- tricity trenerate a very much greater quantity and at a very much lower pressure than is the case with the form called static electricity, and the production is usually continuous and more or less uniform. The distinction is not at all an arti- ficial one; the very existence of static electricity implies a degree of insulation sufficient to retain the electricity until a high pressure has been produced ; while with dynamic electricity the natural process is for it to have a conducting path along which it can flow as fast as 1 it is generated. The flow of dy- namic electricity takes place as naturally as t he flow of water from a higher to a lower level, or as the movement of the water or 1 he air _ when The hand is passed through it. Dvnamic electricity is really akin to mechanic motion, while static ' to a tendency to motion produced by an ',< f<>rcc which DYNAMIC KLK< TUIC1TY f rom which it has a tendency to full is representative of the force pro- ducing static electricity. Fig. 04 shows another comparison between electricity arid hydraulic power. The piston, p, moves in consequence of the pressure of the water in the cylinder, and is supposed to be connected with an engine so as to perform work. To do a specified amount of work or move a certain distance against a certain resistance' requires a certain water pressure or difference in level between the water in the reservoir a than in the reservoir b, and also implies a flow of water through the tube and cylinder w as the piston moves forward. In such a ease the tube and cylinder w, tr, and w, by which the water is transmitted from the upper to the lower reservoir, presents a certain amount of frictional resistance, and a certain amount of work is expended in overcoming this. It makes no difference how much water is contained in either reservoir, provided it is at the required difference in level. The hydraulic pressm-e of a column of water so many feet in height may be compared to the electric tension or to a certain number of volts difference in potential. The frictional resistance in the tube and cylinder may be compared to the ohmic resistance of the conducting wire, and in corroboration of the doctrine of the conservation of energy all the work so expended reappears as heat or light. The rate of now of the water through w is comparable to the rate of flow or the amperage of the electric current. The work done in moving the piston p. and whatever may be attached to it is equivalent in our simile to the work done by the electric current in producing electric, or magnetic in- duction, with or without motor ef- fects, and various chemic, physical, and physiologic results. The rate of flow is increased by increasing the pressure (height of the column of water or number of volts difference in potential); by reducing the frictional or ohmic re- sistance, and by reducing the resis- tance to the motion of the piston p, or the amount of work to be performed by the current. To make the comparison with the case of two bodies charged to a different potential and then connected by a simple conducting wire we have merely to im- agine that the piston p is left out and friction of the tube w is the only resistance to be overcome. The diagram, Fig. 64, would be strictly comparable to the case of a constant potential electric battery if we should introduce a pump to transfer' water from the lower to the higher tank, so as to maintain the two at exactly their original levels. In such a case there would be a uniform circulation of water through the apparatus, just as there is a uniform current of electricity through a buttery and its circuit. Two bodies which are charged to different electric potent ials. but which are simply allowed to discharge hv making an electric connection between the two would be represented by I'iir. 1 55. Here there is a dif- ference in level at the start, and the pressure of the water causes tl piston to advance and the \vater to reach the same level in both cylinders. Then the pressure in each direction becomes equal and motion ceases. Fin. G5. Comparison with hydraulic Work will be performed as the SI I I \vnamic electricity. including all kinds of electric currents, may be likened in an 1 pase in a very short t ime. This would correspond with the effect of connecting the 1 \vo poles of a battery or of a dynamo by a short, thick wire, producing a short circuit. The effect on a galvanic batterv is to cau-e a very heavy current to flow and to quickly exhaust the battery. In the case of a dynamo there is such an overwhelming supply of elect I'icity that the excessive flow of electricity in consequence of an accidental .-hort circuit will burn up a knife blade for example, and fuses are always provided to cut off the current entirely in such an event . If the tube is of considerable size except at a part between A and B, where it is as small as the opening in a gas burner, we know that a cer- tain difference m pre.-sure in A and B will cause a flow of air through the narrow part at a certain rate, and that a greater difference in pres- " <"iu~e an increa-cd rate of flow. If the opening is larger, the how i- n real ej' under the same difference in pressure. For dia- have drawn the simplest form of air pump, but '"'-in'-; tliai i ; i- a turbine' or some other form capable of producing a continuous- effect, not an intermittent one. I: i riff portion- of the tube correspond to the -mall openinu to the p ;t rt of the circuit where 'he current is utilized. Tin- may be, for example, an electric lamp or a iralvamc cautery or the ti.-sues of j},,. human bodv. The difference in DYNAMIC ELECTRICITY 81 pressure in the case of electricity is called difference in potential or volt- age. The rate of flow or the strength, or more 1 technically, the intensity of the current is expressed in amperes; one ampere transport ing one coulomb per second. The resistance is expressed in ohms. The re- lation between these is such that one volt will send a current of one ampere through a resistance one ohm; and that 'various other values V follow the formula C = p-. The current in amperes equals the number of volts divided by the number of ohms resistance. There is another element to be considered, namely, the amount of work or energy required corresponding to the amount of work measured in foot pounds performed by the pump in our illustration. Naturally a greater amount of work is required to maintain an increased differ- ence of pressure at the two sides of the same opening and produce a corresponding increase in the flow of air. In the case of electricity the energy required is proportional to the square of the voltage if the current remains unchanged. The energy required is inversely proportional to the square of the resistance if the currrent remains unchanged. The energy required is proportional to the current if the A Fig. 68. Air pump with valves in the piston and at the two extremities of a pipe through which it forces air in one direction only. Illustrating a direct electric current, hut not nearly so well as if a turbine produced constant pressure in one direction instead of the to-aiid-fro motion of the piston. voltage remains unchanged. The heating effect in a given conduct- ing wire is simply proportional to the strength of the current. The most important fact derived from these relations is that a ! a foot a second. The particle's mem 1 a fe>ot a second, but the impulse S'J MKDICAI. KLK( TKH1TY AND RONTGKN HAYS which starts the different particles in motion all along the lino is vory much more rapidly transmitted. A long chain hanging from a pulley might be drawn up at the rate of one foot a second, every link moving at that rale, but the lowest link beginning to move practically at the same moment as the highest one. Tlie impulse to movement may be transmitted much more rapidly than the movement of the individual links. With electricity the elec- trons move at different rates of speed under various conditions, for instance, at an average of 20. 000 miles a second in an rr-ray tube; but the transmission of the impulse is at a uniform rate of 185, 000 miles a second under all conditions. The last figure is considered the velocity of a cm-rent of electricity and is the same as the velocity of light. Water under a slight pressure may simply flow out of a horizontal opening an inch in diameter like pouring water out of a pitcher; while water under great pressure from a vory high tank or from a si earn engine may be projected from such an opening with force enough to knock a man off his foot. This is analogous to the difference between a high and low voltage applied to the same resistance and assuming that the supply of electricity is ample in each case. SOURCES OF DYNAMIC ELECTRICITY The production of electromotive force occurs in consequence () f ;i vor\ groat variety of natural and artificial causes. Kleotric currents in useful amounts, are gen oral oil by chomic action, by heat, by the motion oi magnets or of coils of wire through which a current is passing. And every vital process in plains and animals and almost every other phenomenon in nature or art are productive of a demonstrable current. 1 ho mere contact ot dissimilar metals produces such a current, and heat applied 1" the junction of two such metals forms the basis of a prae- ::. ilo type < if electric bat t orv. THE VOLTAIC OR GALVANIC CELL To understand the modern thoorv of dynamic electricity it will be useiui to consider tiio case of a simple voltaic cell i Fig. 09), consisting of a jur p, 'tly full of dilute sulphuric acid in which dip a plate of zinc o ' I copper. The two plaies are connected outside of the liquid h\ a copper .. re. which is a good conductor of electricity. The chomic ric acid upon i he //me produce- an electromotive ';'' .<'...' rough t ho liquid from t he zinc to 1 ho copper, and i- ci in tin uod t hr !gh 1 he u ire out side o] the cell irom t he copper to the /inc. Tlii- i- takinu the direction of the positive current as that of II, r ciiri'i nl . The Theory of Arrhenius ' l>s? .- In an electrolyte. /. < ., such a fluid as the diiuie siiipiiuric acid m the batterv which we are consider- ing, the molecule- contain two kind- ot ions which are elect ricallv asso- ciated with their re-pective electric charge.- before the generation of electromotive force. Th'- ion.- move about irregularlv amonu' the water molecule-, -onieiime- approaching and sometimes receding from of the opposite kind. \\ h''li a ' lil'fereiico of pot ent ial i- est ablished let \\-een the two electrode- by the chomic action of the acid upon DYNAMIC ELECTRICITY the zinc, a directive influence is exerted upon all the free ions in the liquid and a general movement of ions in opposite directions takes place. The negative ions all move toward the zinc, and the positive ions all move toward the copper. It is not to be supposed that any individual ion moves the entire distance from the zinc to the copper or from the copper to the zinc. Any one ion may move only a short distance through the liquid and then become bound again. There; is probably an interchange of ions all along the line, and the final result is the liberation of free molecules or radicles of an electropositive substance at one electrode 1 and of an electronegative substance at the other. In the case 1 of the voltaic battery which we are describing the electropositive substance which is liberated is hydrogen gas, and this makes its appearance upon the surface of the copper plate. The electronegative substance is the acid radicle SO,, and this enters into combination with the zinc, forming sulphate of zine-. It is really the chemic affinity of the zinc for the acid radicle that has star eel the entire process, and many of the great physicists of the present elay believe that chemic affinity is only a manifestation of electrie-ity. The chemic change is noted only at the two electrodes. Throughout tin- rest of the liquid the changes which are going on are subatomic and produce uo effect which can be 1 recognized by chemic analysis. Asso- ciated with, and in consequence of. the movememt of the two kinds of ions through the liquid there' is a current of electricity through the liejuid from the zinc to the copper, and this same current is continued outside of the liquid in the Avire connecting the two electrodes. The current outside the liquid passes from the copper to the zinc, com- pleting a circuit. If the two metals are not eonneeteel by a Aviie outside the 1 liquid, in this particular case- there 1 Avill continue to be- some action of the acid upon the zinc, and some 1 liberation of hydrogen upon the surtace ot tin- cupper, but these- will not be nearly so vigorous as when tin 1 circuit is completed. Many voltaic ivlls are made- up of eld trodes and an electrolyte between which no chemic action takes place on open circuit, and in these, of course, it is not necessary to lift the elect t TO in the liquid in order to prevent was! e i ful chemic action Avheu the- bat- tery is not in use. This must be done. In >wever, AVU h the simple vi It aic cell with zinc and copper elements and a -ulphuric acid electrolvte. \\hile the circuit is closed bv the connecting wire outside the cell chemic act i on goes mi in the cell, and an elect romot ive force is iz'ei 84 MKDICAL KLK( THICITY AND KllXTdKN KAYS and, therefore, the maintenance of the electromotive force, are liable to very serious reduction by polarization, interference due to the accumulation of hydrogen gas upon the surface of the copper plate. Voltaic cells are made in which the action is uniform, ami in such a cell an electric current continues to How at quite a uniform rate until the zinc has been completely consumed by the acid or until the acid is all used up. The production of the electric current in such a case is analogous to the evolution of heat in consequence of ordinary combus- tion, and the quantity of electricity produced is proportional to the amount of zinc consumed. The current is of greater volume from a large cell with a large surface of zinc exposed to the action of the acid than from a small cell, but the potential or pressure or voltage is the same. The electromotive force, measured by the voltage, depends upon the difference in potential between the two elements. Two copper plates in dilute sulphuric acid would not produce a current, and neither would two zinc plates. Providing a suitable electrolyte is used, a zinc and a copper element will produce about 1 volt, while a cell in which the positive element is metallic mercury, and the negative element is zinc, and the electrolyte a paste consisting of mercurous sulphate in a saturated solution of xinc sulphate, produces an electro- motive force of about 1.4.'iG volts. The electromotive force determines the amount of electricity which a battery will force through a certain resistance. If the resistance of the human body under certain circum- stances is 2000 volts, a single zinc-copper cell will send through the body only about .j, T 1 IJ() ampere, no matter how large the cell may be or how many amperes it may be capable of producing. When a battery is short-circuited, or the copper and the xinc are connected outside the liquid by a conductor with practically no resistance, the amount of current that will How is proportional to the amount of xinc exposed to the action of the acid, and the larger the cell the stronger the current. Voltaic Cells in Series and in Parallel. When two or more cells are connected in such a way that all the copper plates are connected with one wire and all the zincs with another and the two wires can be brought together as the opposite terminals of the battery, the cells are said to be connected in parallel. The connection in series is made by connecting the zinc of one cell with the copper of the next, making a series of which one extremity is the zinc of the first cell and the trther ext remit v is the dipper of the last cell. The two battery wires pass from 1 hese t \vi ext ren ,11 ies. A bat t erv set U]> in //nrnHi I nr tn ulti/ili acts like a single cell with a large amount of xinc surface to be exposed to chemic act ion. The current pro- duced is of t he same larire quant it y as if the zinc surfaces in all the cells were added together in one lui'ire cell. If the battery is made up of twenty cell- in parallel, and all of the same size, the current strength on short- circuil \vill be 1 went \ t imes us great as wit h a single cell. 'I however, will be the same as would be produced by a single very larire number of cells connected in parallel will not se elertricitv through the human bodv than ;i few cells. A is about the same as with a single << DYNAMIC KLKCTIUCITY S."> voltage is proportional to the number of cells. The current which it will send through the human body is proportional 1o the number of cells, and with a very large number dangerous shocks may be given. The electromotive force of all the cells is added together, while the quantity ot electricity generated remains the same. On short-circuit the current will be no more with twenty cells in series than with a single cell, but when there is a certain amount of resistance in the circuit outside of the cell, the current which one cell will send through that resistance is less than on short-circuit. The current which twenty cells in series will send through a large resistance may be about twenty times what one cell would send through the same resistance. Of course, the amount of current sent through the resistance is limited to the maximum output of a single cell in the case of a series battery. The amount of zinc consumed is the same in both cases, and the same amount of power is generated. The difference between the two types of buttery is analogous to that between two steam-engines con- suming the same amount of coal, and producing the same amount of power, but one geared to move a heavy weight slowly, and the other to move a much lighter weight at a correspondingly rapid rate. In mechanic motion it is practically true that it takes the same amount of power to lift a body weighing one pound 100 feet, as to lift 100 pounds one foot: and the motion of the two bodies may be caused by suitable transformers to yield the same amount of power. In mechanics the unit of power is the foot-pound. In electricity it is practically true that the same power is required to produce a current of one ampere and ten volts as to produce a. current of ten amperes and one volt. And by suitable transformers the same amount of power may be obtained from the two currents. The unit of electric power is the \nttL or the volt-ampere. A watt is produced by a current of one ampere with a potential of one volt or by a current of smaller quantity and a cor- respondingly greater potential. Thus a current ot ^ ampere and 10 volts produces a watt. And, on the other hand, ;, larger current at a correspondingly smaller potential will product 1 a watt. In any case the number of watts is found by multiplying the number of amperes by tlie number of volts. The physical and physiologic effects produced by a certain amount of energy in the form of a current of high potential and low amperage are radically different from the effects of the same amount of energy as a current of low voltage and great amperage. In t he cas: 1 of t he volt ale bat tery and of t he generators of elect ricity known as dynamos the -ame amount of energy may generate 1 a current of hiu;h voltage and >mall amperage or the reverse, according lo tin- way in which the different elements are connected up. And in all these cases the current may be converted from one type to the other without material loss of energy'by suitable apparatus. Voltaic cells of all the different materials used as elements and electrolytes vary but little in the voltage produced by a >inNT pieces of metal are to be heati d red hot, the ordinary electric current from a dynamo is changed by a transformer to one of only about five volts, but of several hundred amperes, while for use in actuating an .r-ray tube the same current of 110 volts is transformed into one of perhaps 100.000 volts, and only a very few milliainperes. or thousandths of all ampere. It is perfectly practicable to transform the current from a voltaic battery into a current suitable for .r-ray work. It is necessary that the batterv should be sufficiently powerful, or should generate a sufficient number of watts. The coil or whatever kind of transformer is used does not add one particle to the power, but only changes its form just a- a pulley does in the case of mechanic power. A battery of from thirtv to sixty full-sized voltaic cells of any good type, such as the Lei 'lanchc or the l)aiiiell. will give a sufficient current for an .r-ray coil 11 mechanic interrupter, but will not produce as powerful a ray as ained from the 110-volt electric-light current generated i. And while a much larger battery would perhaps do t he a~ the electric-light current, it would cost much more, a-iu'enients have shown that the electric energy obtainable .-: ii bv the combustion of a ton of coal is six times that m 1 he consumption of a ton of zinc in voltaic batteries, e, cl ton o[ /inc costs a great deal more than a ton of latteries are desirable only for purposes requiring a . verv small current, and that only for short periods too frequent intervals. The small current makes the nail as to be less than it would cost to install the neces- rtln use of a current from u dynamo. And the short ods of use keep the cost of maintenance within In the author's experience, however, the electric- belter results for all kinds of therapeutic work. depr DYNAMIC KLKCTKICITY S7 upon the number of amperes of current passing through the circuit, and this can be regulated in 1\vo ways: in the case of a voltaic battery by using large colls or a sufficient number of parallel cells to produce the required amount of current, and adding cells in series with each of the parallel cells, making a number of parallel series producing the voltage necessary to send the necessary amounto f current through the resistance of the circuit: with the electric-lighting current the regulation is accomplished either by the simple introduction of the necessary resistance in the form of a rheostat or by the use of a trans- former. The rheostat adds its own resistance to that of the rest of the circuit, and the number of amperes which will pass through the circuit is found by dividing the number of volts (110) by the number of ohms resistance in the entire circuit. A shunt may also be used as a volt controller and the strength of current regulated in that way. Maximum Efficiency. The law thai the maximum efficiency of a source of electricity is obtained when the external resistance is equal to the internal resistance of the generator is sometimes misleading in its practical application. In the first place, it does not refer merely to the intensity or volume or the number of amperes of the current sent through the external circuit. It refers to the total energy sent through the external circuit, or, in other words, to the number of watts, or the number of amperes multiplied by the number of volts. In the case of several generators, n, each of which has an invariable electromotive force K. and internal resistance r, i'ormuhe may be calculated for their connection either in series or in parallel, or both combined to produce the greatest number of watts in the external circuit. This maximum is obtained when t R <] R n R - or when t * / q r r \ r t being the number of groups set up in series, and q the number of cells in parallel in each group. If R -=!', then t = q = i/n, or if the external resistance is equal to the internal resistance of each cell, the maximum effect is obtained by making the number of cells in each series equal to the number of series, thus with o(> dividing them into n' series of (> parallel cells each. It' R r then t q. or if the external resistance is greater than the internal resistance of each cell, the number of groups set tip in series should be greater than the number of parallel cells in each group. It' r 1! then t q. or if the internal resistance in each cell is greater than the external resistance, there should be a greater number of parallel cells in each group than there are of groups set up in series. The following equations are examples: 1. In the case of a battery of M(> elements, each with an electro- motive force ]] equal to l.."> volts and an internal resistance r equal to 2 ohms, used for applying a voltaic current to the human body iwith a resistance K equal to 1000 ohms"), the equation would be t - 1000 A >) - possible to a maximum t should equal n. or the serie^ number should equal the total number of cells. The entire )>(> cells should be set up SS MKDICAL KLK< TK1CITY AND KONTCKX HAYS in scries to send the greatest number of watts through the human body. 2. For electrolysis with a resistance II of 20 ohms the equation would lie that is. there should bo a series of IS groups (each group containing 2 parallel cells). :>. For cautery with an external resistance U equal to ()."> ohm the equation t<> pro* luce the niaxiniuni number of watts in the external circuit would lie 0.5 \ 2 thai is. there should be a series of three groups (each having 12 parallel cells). Sparking Distance of Voltaic Batteries. The sparking distance obtained from a voltaic battery increases in about the same ratio as the voltage. or a little faster. A battery of Ue la Kue chlorid of silver cell- witii a voltage of 1000 produces a spark about -., i () - inch long: .">xOO such cell- .-park across a space of -/- inch; 1 1,000 such cells .spark across a -pace : it -] inch. Thin v or forty voltaic cells in series will give not only a spark, bin an arc between the bare ends of the two insulated wires if they are fir-l brought together and then slightly separated. There is a certain amount of noise produced, and sufficient heat to vapori/e particles from the two metal surface-. If the individual cells are small, the amperage and the volume of the arc \\ill be small; while if the cells are large or each member of the series is formed by a number of cells in parallel. 1 he av will ut some L r ood conductor, like metallic copper, upon the DYNAMIC KLKCTRICITY 89 surface of the copper. A solution of sulphate of copper is used, in one of the best two-fluid cells. The zinc is in a solution of sulphate of zinc and the copper in a solution of sulphate of copper; the two solutions being in electric connection through the porous wall of the jar thai separates them. In this case; the substance deposited upon the cnppei plate is metallic copper, which aids rather than impedes the current. Xo cell in which polarization is not provided against is suited for regular electrotherapeutics purposes. Local Action in a Voltaic Cell. A piece of pure zinc, such as may be obtained by distillation, is not affected by 10 per cent, sulphuric acid if dipped into it alone or with a piece of copper, unless the external connection is made which permits the electric, current to flow. And in a battery in which the zinc was absolutely pure, the consumption of the zinc would cease while the current was turned off by opening the external circuit, even though the zinc and copper still remained in the dilute acid, \\ith ordinary commercial zinc this is far from being the case. The zinc continues to be acted upon even on open circuit. This is due to particles of impurity in the zinc, each particle forming a voltaic couple with the neighboring portion of zinc, and setting up an electric current with an accompanying consumption of zinc by local action. No effect is produced upon the copper plate. This same local action also occurs during the use of the battery. It causes a waste of zinc while the battery is in operation, and renders it necessary to lift the metals from the acid when the current is turned off. An extremely simple means of preventing local action consists in amalga- mating the surface of the zinc by coating it with metallic mercury, and quite recently a manufacturer in Rhode Island has been able to melt zinc and mercury together in such a way as to make a complete mixture of the two through the entire mass of the zinc. Amalgamation removes the impurities and leaves the surface of the zinc covered with a liquid layer of pure zinc dissolved in mercury. Zinc so prepared is as free from local currents as if it were a plate of chemically pure zinc. It is not affected by the acid while the current is turned off, and there is no useless consumption of zinc while the battery is in operation. An easy way to amalgamate zinc is to dip it in hydrochloric acid, and after drying it, to rub a few drops of mercury over its surface with a cloth. In the case of a cell in which the zinc is not amalgamated, the local action which takes place on open circuit, i. c., when the wires are disconnected, is seen only at the surface of the zinc, where a consump- tion of the metal occurs and there is a liberation of hydrogen gas. The power generated by the consumption of the zinc on open circuit is wasted as heat, the temperature of the acid rising in proportion to the activity of the effect upon the zinc. The Component Parts of a Voltaic Cell.- The elements forming a voltaic couple may be two of the ordinary metals, or a metal and car- bon, oi 1 two liquids, or even two gases. For practical purposes the elements are always of the first two classes. The electrolyte is almost ahvays a liquid, and must conduct electricity and be decomposed by it. The ends of the elements which project above the surface of the liquid are called t he polr* or t !<<( rodis, and to them are at t a died t he conduct ing MKD1CAL ELECTRICITY AND HoNTCKN HAYS is closed. This is the case no matter what an affinity the electrolyte may have for each of the electrodes separately. The electrode which is acted upon is always the electropositive one; thus, m the case of the zinc and copper couple in dilute sulphuric acid, only the zinc is acted upon, and eventually the zinc is entirely consumed and the acid changes to a solution of sulphat< of zinc. It', on the other hand, the two ele- ments had been copper and graphite, the copper would have been the electropositive element and would have been the one to be acted upon. Any metal in the electromotive series' is electropositive in relation to a metal occurring later in the list. The direction of the current through the electrolyte is from the electropositive element to the other. This is the direction of the positive current. This is just the opposite of the direction of the movement of the electrons, but it seems too late to change the time honored designation of the ''direction of the current." < hitside of the liquid, however, the positive current is continued from the copper to the zinc, so that the copper forms the positive pole of the baUery and the zinc the negative pole. This is a little bit confusinu 1 . but it is none the less the fact that the electropositive element forms the negative pole of the battery as far as the external circuit is concerned. Wiien the two pules are connected outside of the fluid by being touched together or by a direct conducting cord with pra.cticu.llv no resistance, the battery is said to be short-circuited, and the maximum possible current will flow. Some batteries give a very strong current on short-circuit, and rapidly become exhausted, while others do not yield much more than t heir normal current and will run for a long time. The circuit is closed when the two poles are connected outside the fluid by a conducting path of anv kind whose resistance may be very small, as in the case of a short-circuit, but is ordinarily quite consider- able. It is in its passage through this external resistance that the work of the current i- performed, and that the power generated in the It is explained n p. ]'.}~ that this external resist- wo kinds -ohinic resistance akin to friction, and nt of current bv converting part of the power it represents into heat; and inductive resistance, by which part of the current -t rentn h ^eems to disappear in consequence of a counter electro- motive iorce induced bv the current'- flow. The force which causes the current of electricity to (low through the liquid and through the con- ducting path outside the liquid is called the chrlrowotii'r force, or the difference m potential between the two pule-. Practical Types of Single-fluid Voltaic Cells. The hichrnmntr fill contains an electrolyte made bv di ''Ivim: one pound of bichromate of potassium in ten pounds of wat er to which two and a half pounds of concentrated -ulp!:';ric acid have previously been slowlv added. The elements are zinc and carbon, both surfaces of the zinc being utilized by placing it between two carbon-. The zinc should be raised irom the liquid when the battery H not in use. Such a cell has an electromotive .!i.~) volts, and makes an excellent cautery battery. ill consists of dilute sulphuric acid as an electrolyte, a plate of silver between two of zinc. It is an excellent cell for -'.h rlrnintili i-i >'.'/' '/.':'..<-. l;it inum. anil irrapi.iti-. DYNAMIC KLKCTHICITY 91 nil kinds of eleetrotherapetttic purposes, h has boon extensively used 1'or telegraphy \vhoro the requirements aro much tho same as in medical work, /. c., tho oloinonts do not have; to bo raised from tho liquid \vhen not in use and tho battery is always ready to yield a lull current when the circuit is closed. To lesson polarization tho surface of the silver is roughened or coated with finely divided platinum. Kaoh cell yields about ().()") volt . Practical Types of Double-fluid Voltaic Cells. Tho Bn-n^-n cell consists of a carbon rod, the positive polo, in strong nitric acid inside a porous cell: and a hollow cylinder of zinc, the negative pole, in dilute sulphuric acid in the large outer glass cell. The voltage of each coll is about l.Oo. The (iron' cell is similar to the Bunsen, but in it platinum is used instead of carbon. The I). It is a type which is very serviceable for medical purposes, and is usually set up in a series battery so arranged that from one to the entire number of cells may lie used. It is a battery which produces a small current with high electro- motive force. It is hardly a practicable type of battery for cautery or any other purpose requiring a heavy current. Some other type of voltaic cell is or a storage battery of several cells in series, or. the electric-lighting current with a suitable better in tiiis wa still mure convenient, tl'ansfi inner and rheostat. Clark's Standard Cell. For measurinsr the electromotive force 1 of mparison, and t ere arc si itne ot IK sufficient to descril ibe wit li silver \\ ' >sn ive mass < >f i a 1 e and . found in the current produced by a. which can be used in the same way. this one in detail. It consists of a. leading in at top and bottom and merctirv covered bv a paste of ihate, and a negative mass of pure ierat ed. and tins is 1 lie reason that 1 he 1 ube I'ming t he elect n >1 vie is mai le -i ilnt ii >n i 'f zinc sulphat e, i keep it semifluid. Tin It- electromotive force is Fleming's Standard Cell. definit e elect roiiiot i ve N >rce. a unki ago. It is m. U-sl DYNAMIC ELECTRICITY is the zinc electrode in a solution of sulphate of zinc, while the copper electrode is in the other arm in a solution of sulphate of copper. Its potential is 1.074 volts. Corrections must be made for temperature with either of these standard cells. The voltage of the Fleming cell, for instance, diminishes 0.08 per cent, for every degree Centigrade of elevation in temperature. The Cadmium Cell. A cadmium cell is another standard cell, and has recently taken the place of a Clark cell for measuring the electromotive force of different voltaic cells. The negative electrode consists of a mass of cadmium amalgam fused on to the end of a platinum wire. It is in one vertical arm of a glass cell shaped like a letter H. The cadmium amalgam is covered with a loose mass of crystals of sulphate of cadmium, and above that is the general electrolyte. This is a solution of sulphate of cadmium, and is the same in both vertical arms and in the horizontal junction of the glass cell. The positive electrode is a plate of amalgamated platinum fused on to the end of a platinum wire, and covered by a paste of sulphate of mercury, which fills the lower part of the other vertical arm of the glass cell. From these two electrodes fine glass tubes lead through the paraffin wax and cork and sealing-wax, which hermetically seal the cell at the top of the two vertical arms. The two fine glass tubes contain metallic mercury, by means of which the conducting rods are placed in electric contact with the positive and negative electrodes respectively. The advantage of this cell over the Clark cell is that it re- quires practically no correction for changes + in temperature. of Silver Cell De La -Each cell consists of a about 6 inches high and 1 inch in diameter, closed by paraffin wax, P. W. The two electrodes are of zinc, z, and silver, s. and the latter is wrapped with paraffin paper to prevent it from coming into contact with the zinc, since the battery is especially designed to be portable. The elec- trolyte is one part chlorid of ammonium and forty parts water. The zinc is the element acted upon during the operation of the bat- tery, and when the battery is not in use, the zinc becomes covered by a coating of oxychlorid of zinc, which reduces the flow of current technically by increasing the internal resistance of the cell. This does not occur if the cell is in frequent use. or if the zinc is taken out and scraped. Less of the oxychlorid of zinc is formed if the cell is hermetically sealed. In any case the full strength of the cell is elicited by a few seconds short-circuit in the case of a cell which has already been in use. or by fifteen minutes short-circuit if the cell is entirely new. The internal resistance of a cell of the size described here and with a zinc rod f\ inch in diameter is three or four ohm.-". The electromotive force is about !.()'> volts. The wire connected with the ;iinc rod forms the negative ( ) pole in the external circuit The Chlorid Rue's (Fig. 71).- glass vessel, g, g. Fit* 71. Chlorid of silver cell. 94 MKDICAL KLKCTKICITY AM) KONTUK.N HAYS DKTAILS OF VAKIol'S VOLTAIC (T.LLS. copper sul- phate. 22 to 1. Saturate. 1 so- O.97S luticm of co], per .-ul- phate. L'2 to 1. Nit rate of cop- 1.000 per t-atu- ratedi. _'2 to 1. Sulphate of o.O'H) copper. Sulphate of Sulphate of l.i>79 zinc -at']- copper 'sat- iated solu- urated -olu- tioil . tioiT. Sulphurie Nitric acifi I'latimim. acid 7V to 1. fuming'. Salt water. N it ric acid. -p. in'.. l.:. Su]])hurif Nitric acid, acid. _'_' to 1. -p. LT-. !.:. Sulphate of Nit rif add, zinc. -p i-'!.. 1..TJ. Dilute Mil- Nitric acid. Carbon. piiurie acid. Sulphuric acid Platinized *il- d.47 1 : water. 7. ver. Sulphuric acid J'latini/ed car- n.r>,") 1; water. 7. bon. 1.4S Silver. Ajrf'l. l.(i 'e : S'llpLa'eof Lead. (I..V) /.'.: lead. N -all ' I., rid of Carb I . 1 .0.1 lin c. I', i lorid ,,f Lead. I. .Ml ; > ite -.il- I i ite M;|- [Mai num. 1 .7!i . p'.urii acid,. l':i te of - ;!- Merc IP I I.TT DYNAMIC KLKCTKICITY Pl.A'I'K. Snl.t'TIONS SKI'AKATKI) I)Y 1'oitorS I'l.ATK. XK<;ATI\K I'OI.K. ('1:1.1.. I'UMTIVK I'OI.K. YOI.I-. l.alande-Cha- /inc amain. Can-tic soda ( )xid of copper Iron. 1 peron. .-olution. 01 "copper scale." Faure's sepon- Lead plate Dilute sul- Dilute sul- Lead j.late 2. to 2.2 Jury battery coated with phuricacid. phurie acid, coaled \\ith minium. minium. Sellon-Volck- Lead plate Solution Mil- Solution sul- Lead plate 2.15 mar. primed with phurie acid. phuric acid, primed with minium. sp. ^i ., 1 . 1 HO. sp. Kr., 1. 100. minium. 1'lante. Lead. Dilute Mil- Dilute Mil- Lead 2 to 2.2 phuric acid. phurie acid. isponny). Testing the Porous Cell in a. Voltaic Cell. The porous cells used in batteries may be tested in two ways: by actual use in a standard cell (British Government test), or by filling with distilled water at a tem- perature of 14 C., and seeing if the leakage in twenty-four hours amounts to at least 1") per rent. (Fronc'h Government test). Precautions in Mixing Battery Fluids. When mixing battery fluids containing sulphuric acid, it is very essential to pour the acid slowly into the water. Heat is produced by mixing the*e two fluids. and if the whole quantity of acid is subjected at once to the action of water, the glass jar or cell will certainly crack. Dry Cells.- The so-called "dry cells" of modern commerce differ in no essential respect from an ordinary zinc-carbon voltaic cell. The amount of fluid, however, is small, and it is held in some absorbent material like sawdust, or it may be in a jelly-like mass. The outside of such a cell is generally a zinc container which forms one electrode, while the other electrode is a rectangular carbon rod around which the electrolyte is pa ked. The can is sealed by a layer of asphaltum to prevent evaporation of the electrolyte. Hatteries of dry cells set up in series are very convenient for actuat- ing a faradic coil or for 1 lie lighter forms of electrolysis and galvanism. They are not verv well adapted to cautery purposes or to ./'-ray work. Fi'rv's recent I v patented dry eel! is claimed to give quite a constant current. The positive pole i< formed by the zinc can containing the 01 1 KM' parts of 1 he bat 1 cry. There is a bottom layer of porous substance, such as infusorial earth, cotton, or powdered pumice-stone, moistened with such a liquid as a- solution of sodium sulphate. The zinc is lined with blotting-paper or felt. The carbon positive electrode is placed in the upper part of 1 he jar, and surrounded by a depolarizing substance, such as a mixture ot graphite and mercury sulphate made into a paste with sodium sulphate solution. Expense of Electric Power from Voltaic Cells. The amount of zinc consumed in a voltaic batter has been calculated to be for one Thi< is very much more expensive than burning coal. oil. or gas to run a dynamo and produce the same amount of electric energy siderable power is required for anv lenti'li of time. 1 nder certain conditions, in electrothera]>y. hoAvever, the voltaic battery economic when only a small amount of power H required .- ' VM) MK1HCAL KLKCTRICITY AND KO.VHiEX RAYS periods, and only for a short time, and when a portable apparatus is required. Kven under these conditions, if there is a dynamo current present for other purposes flight or power), it may often be employed with economy for medical purposes. It certainly makes it much easier to keep the apparatus in running order. Method of Measuring the Electromotive Force of a Voltaic Cell. This is most accurately accomplished by means of an apparatus called the potentiometer. This is essentially a balancing of the electromotive force to be measured by the electromotive force of a standard cell. (See p. IDo.) For less precise measurement of the electromotive force of a voltaic cell a galvanometer with a certain resistance may be used, and this may be marked in amperes or volts. In either case the instrument may be only the size of a watch, and is invaluable for such purposes as testing the condition of a dry cell which has been kept in the shop some time before being sold, and perhaps may have been exhausted in con- sequence of some accidental contact. The Internal Resistance of a Voltaic Cell. The current from the zinc to the copper through the dilute sulphuric acid in the simple cell which we have described encounters a certain amount of resistance. This internal resistance varies with the different cells according to the component parts of the cell, the electrodes, and the electrolyte, and also with the size of the cell. It is usually equal to two or three ohms. There are two perfectly easy ways of determining it. One way is to connect the poles of a single cell with a galvanometer and note the strength of the current; then connect two such cells in multiple, for instance, both zincs with one conducting cord, and both coppers with the other; this reduces the internal resistance one-half, and this reduc- tion is measured by introducing a variable amount of resistance by means of a rheostat, and increasing this until the galvanometer indicates the same current strength as when only one cell was used. The increased resistance required is equal to half the internal resist- ance of a single cell. The formula for this calculation depends E upon the equation C = - , indicating the law discovered by Ohm that 1\. the current is equal to the electromotive force divided by the total resistance. The current is expressed in amperes, the electromotive force in volts, and the resistance in ohms. The resistance in the case we are considering is made up of two factors the resistance of the cell itself, K. and the resistance of the galvanometer and the rest of the external circuit, r. I'sing a single cell, therefore, the equation would read ('- ' : and if the additional resistance required to keep the same current Mrength in the case of two cells is L. then the equation would read ('- : and since 1 the strength of the current (' is the same on p. '2'-'>\. The knowledge of the internal resistance of a voltaic eel] i- of value a> one of the fact oi 1 .- in the calculation oi the number and arraimement of cells for -ending a certain number of amperes of cur- rent throimh a certain number ii ohms' resistance. DYNAMIC ELECTRICITY ( .b The Original Voltaic Pile.- Yollu, professor of natural philosophy at Pavia, in 17 ( .)(>, devised the electric battery, from which all those so far referred to as sources of dynamic electricity have been evolved. It consisted of a series of two different metals, piled one upon the other, and separated bv cloth or paper moistened with an electrolyte. The metals were sometimes silver and /inc. and tlie electrolyte, water or salt and water: and in other cases zinc and copper were used with dilute acid. The current was produced by chemic action and there war- no principle involved which has not already been explained in describing tin 1 modern types of voltaic battery. At the upper and lower extremi- ties of the pile the two poles of the battery were formed by dissimilar metal disks. Kach pair of dissimilar metals separated by the cloth moistened with the electrolyte formed the equivalent of one of the modern voltaic cells. In the pile the zinc element of one couple wa- in direct contact with the copper element of the next couple, the succes- sion being zinc, moistened disk, copper, zinc, moistened copper, etc. It formed a series battery the voltage of which could be raised to any reasonable 1 amount by increasing the number of disks, but the quantity of current was very small. This type of battery is not in use to-day for medical work. Dynamic Electricity from the Contact of Dissimilar Metals. Two dissimilar metals merely placed in contact in the air will produce an electric current, but this is most powerful when one of the metal- is oxidizable and when they arc dipped in a good electrolyte. According to Yolta's observations, any of the metals mentioned in his contact series becomes electropositive when in contact with any one below it in the scale. Starting from the positive end of the scale there are sodium, magnesium, zinc. lead. tin. iron, copper, silver, gold, platinum, and graphite. The voltage obtained by Yolta by the contact of zinc and lead was 0.211); tin and iron. 0..'Jb>: even cork in contact with platinum produces an electromotive force of 0,11.') volt. Two different metals in contact in the air generate electric currents whose voltage is given in the foll< iwing: ('ontttct Si rii's of .Vr/f;/.v hi Air. Kach metal is 4- in contact with all following: Sodium, magnesium, zinc. lead, tin, iron, copper, silver, gold, platinum, graphite. Contact K.M.F. in volts: o.L'10; lead-tin. O.OiiO: tin-iron. ()..'! I.'-}: iron-copper, platinum. O.'JMS; platinum-carbon, 0. li:-> lAyrton and Perry). Heating of Voltaic Cells. The amount of heal generated in a voltaic cell depends upon the chemic constitution of the cell, not simply upon the current strength. This is shown in the cases of the cadmium cell and the Clark cell. Both are standard cells. They generate a perfectly definite electromotive force, which is used in measuring electromotive forces and resistances. The cadmium cell generates thirty times less heat than the Clark cell, and underlie- comparatively little change in electromotive force while in operation. Thi- constitutes a- great advantage over the Clark cell, in usinii which the temperature changes must be measured and their effect upon, the electromotive force 1 calculated. THERMO-ELECTRICITY A difference in potential is generated when the junction bet wee two different metal- is heated or cooled, and this will produce an eler 7 MEDICAL ELECTRICITY AND RONTC.EN KAYS trie current if the two other extremities of the metals are connected by a wire. This property may be used to generate electricity for medical purposes, and a large number of such couples will give a cm-rent of high potential or of great quantity, according to whether they are arranged in series or in parallel. As long as a difference in temperature is maintained, so that the junction of the metals is either hotter or cooler than the distal parts of the metals, a current will flow. Corrobo- rating the theory of the conservation of energy, a certain amount of energy in the form of heat must be applied, and disappears as heat, to reappear as electricity. A thermo-electric pile or battery is not convenient for therapeutic purposes, but it may be used as a very delicate thermometer. A wire of one metal is' bent into an inverted U-shape, as in Fig. 72, and others of another metal are soldered to its two extremities. Plac- ing one of these junctions in a disk of melting ice whose temperature is, of course, known to be exactly .'>2 F., and the other in a solution whose temperature is to be tested, a current of elec- tricity will flow through a galvanometer con- nected with the free extremities of the outside wires if there is any difference in temperature be- tween the two solutions. The galvanometer devi- ations corresponding to different temperatures must be determined by the manufacturer of the apparatus and marked upon a scale. This fur- nishes very delicate measurements of the tem- perature of any part of the human or animal body, to which one point is applied while the other point is dipped in melting ice. The exact temperature of any part of the body may be determined in this way. Thermo-electric Scale. In connection with lead, at a mean tem- perature of 20 ('. (.Matthiessen), the E.M.F.'s are in microvolts per degree centigrade: I'.i-muth, commercial, in wire -M 17.000 pure, in wire ---S'.UIOO " crystallized., alomr axis +(1.1. 000 normal to axis - : l.VOOO Col,:,]! j I'!'. 000 (iermaii silver'... . : 1 l.7.">0 Merc ir\ . . O.-US ( 'i ij ,| ii T n! ci 1(1 111 lel'ci 1111 C,nl,\ Ant inmny, pure, in \\ ir ' Zinc, " DYNAMIC ELECTRICITY 90 STORAGE BATTERIES OR ACCUMULATORS These are cells which, after being charged by the electrolytic action of a current passed through them, act exactly as do the ordinary voltaic cells. They are of service where there is a dynamo or similar source of electric current, which is either not available at all hours, or which is liable to derangement, and also when a portable outfit is required. The general principle upon which all storage batteries work is illustrated in the case of one of the older types made by the Thompson- Houston Company. It contained a copper electrode at the bottom, in a solution of sulphate of zinc, with a zinc electrode near the top. A current of electricity from a dynamo or from a primary battery was passed through this cell from the copper to the zinc. This decomposed the solution, depositing metallic zinc, upon the zinc plate, and by dis- solving away the copper from the other electrode, produced a concen- trated solution of sulphate of copper at the bottom of the cell. The result was the formation of a regular Daniell cell of the gravity type, with the zinc electrode at the top, the copper at the bottom, and the two electrolytes, sulphate of zinc solution at the top, and sulphate of copper solution at the bottom, kept separate by their difference in specific gravity. This battery was then ready to give a current when the external circuit was made between the two poles. The direction of the current of discharge was the reverse of that of the charging current, so that the copper became the positive pole, just as in an ordinary gravity battery. The current-yield would continue, while the external curcuit was closed, until the solution of sulphate of copper had again entirely changed to a solution of zinc sulphate. The battery could be recharged by passing an electric current through it in the same way as at first. And this alternate charging and discharging can be repeated a large number of times, though eventually the electrodes are worn out and the electrolyte also needs renewal. While charging such a storage-cell, metallic zinc is deposited in a loose form, and a diaphragm is needed to keep it from falling to the bottom of the solution. The Plante Storage Battery. The Plante cell is the original upon which the other modern storage batteries are modeled. In it two thin sheets of lead separated by a fraction of an inch are coiled together, securing a very large extent of surface and a small distance at all points between the adjacent surfaces of the two plates. They are set in a jar of dilute sulphuric acid, and a conducting cord is attached to each plate. In this condition no current is produced on closing the circuit, because both plates have exactly the same affinity for the electrolyte and no difference in potential exists. The battery is charged bv passing a current of electricity through it. Electrolysis or electrochemic decomposition takes place, by which the lead plate connected with the negative source of electricity becomes coated with finch" divided metallic lead, derived from the action of the acid upon the other plate, -url'ace of that one becomes converted into red lead or peroxid ile. then, with the storage-cell fullv charged, we have and at the other, I'M),. Removing the battery current, it is ready to act like an ordinary voltaic; a current when its two poles are connected through The pole on which the I'M)., nvd lead or peroxid deposited becomes the positive polo of his to the 01 MKD1CAI. KLK< TRK Tl'Y AM) KnXTOK.N HAYS In The liquid electrolyte of the battery, of course, the current is con- tinued t'ri'in the Pb to the PbO... The react mn occurring as the total result of the discharge of a storage buttery is Pb - PbO., - 21I,S< ), , 2Pb- S i. 2H..O. uti'i during the process of charging or recharging the saine equation'holds good, but would be reversed: 2Pb.SO, 2H..O Pb - rbo., -2H,SO 4 . In other words, during the discharge, the metallic lead on one plate and the peroxid of lead on the other both yield to the influence of the sulphuric acid and are converted into sulphate. The dilute sulphuric acid becomes weakened, and solid sulphate; of lead is produced. It is ne\ er desirable to allow a storage battery to become completely dis- charged, all the peroxid of lead disappearing, both plates becoming converted into PbO. or litharge, and the electromotive force falling to xero. In this condition it receives a charge much less readily and effectually than if one plate still had a considerable coaxing of peroxid of lead. For the same reason, when first making a storage battery, it is preferable to apply a thick coat of peroxid of lead i red lead) to one or both of the lead plates, the battery then "forming 1 ' much more quickly. .More closely atialyxed. the reaction in a storage battery during its discharge consists partly in the formation of about equal quantities of solid lead sulphate at each pole, and a reduction (.if the strength of the acid occurs at both poles, but is more marked at the positive pole. One result of the discharge is seen at the anode, -where the lead combines with a sulphion to ft >rm sulphate of lead, and transfers a negat ive charge of electricity to the liquid in the direction of the cathode. The equation Pb -.SO, PbSO,-;-2 expresses the reaction occurring at the positive pole. The reaction at the cathode is exprc.-sed by the equation PbO.,- 1 - If ..SO, -I'll. _'-- PbSO^-L'ILO. which indicates that peroxid of lead. with sulphuric acid and hydrogen and a negative charge, result in the formation of sulphate of lead and water. When the storage battery is being charged, the same equations also hold good, but are simply reversed. Wit h t he strength of acid i >rdinarily used, a storage-cell cool- slight !y while yielding a current. The full explanation of why this should be the '.;-( instead of the fluid becoming warm, as with the Daniell cell, i.- beyond the scope of the present book. But two factors are that the re- i Its i ft he chemic "hange are much weakened acid and solid lead >ulphaie. and that the internal resistance' of a storage-cell is very much -i . er - . I hat of an ordinary voltaic cell. \\hen a .-torage battery i- beii '_: reel arged. t he electrolyte acquires its con d it ion of being quite a strong solutioi o] -ulphuric acid, and the prof-ess should be continued 11111 . '_'.-:-<- are freel' given off from the electrolyte, which becomes slightlv warm during the process These ga-e- are hydrogen and xyirei . ' , ' e pre-em-c of ;i spark or flame would cause an ex pi o- ion. The large bubhle< are hydrogen. 1 he small one-, oxygen. The sulphuric acid ei as a den sit v of ] .Is or 1 .20. and is much stronger than "dilute sulphuric acid." A- the water evaporates, di.-tilled water is t he be^t to ;i . - i>e it brings about no change in 1 he com posit ion ol the electrolyte, while ovdinarv water contains an amount of chlorids ' er -everal addit ion-, to impair 1 he efficiency of t he cell. 'I he modern storage battery i- made up of grid-, which are molded form- of lead producing hardly more ' : ;i'i a framework until thev are '"'pasted." The L r rid which i- to form the ]io-iii\-e pole of the storage DYNAMIC KI.KCTKK 1'1'V 101 batterv is '' pasted, " or thoroughly tilled under hydraulic prosMiio. with a paste of ml lead and some substance which will he dissolved out l>v the \veak sulphuric acid, and leave a porous mas-; presenting a rela- tively very lar^e surface of peroxid of lead exposed to chemic action. The other .arid is pasted in the same way with spongy lead. The active surfaces presented are ahout '200 or 100 square inches per pound. '1 IMS met hod of construction also prevents t he separat ion of 1 he act ive layer. The surfaces of the positive and negative "rids are placed very close together, being kept from actual contact hy a corrugated sheet of hard rubber with numerous perforations, and also by a thin piece of bass wood. The latter, under the action of the acid, becomes :',0 per cent, porous, but still has such fine pores that it effectually prevents the formation of a lead tree. The hitter is a sort of crystalline mass ot lead, looking like the familiar Christmas tree, which would have a tendency - to form between two lead plates in a storage batterv and very greatly impair the efficiency of the battery. A storage battery is usually made up with three positive ami two negative "'rids in each cell. This does not increase the voltage of the cell over what would be the case with only one plate ot each kind. It does, however, increase the amperage and does so in a manner more economical in regard to sixe and weight than \vi ni Id be the ca.se wit h a single pair of c< irrespom tingl v larger plat es. Five such cells would have a potential of about 10 volts, and would give a current of about 10 amperes, through a resistance of I ohm. for about ten hour- continuously, or as the total of several shorter periods. A bat tery of t his capacit v weighs in mi 100 to -00 pound-. The chlorid type of storage battery, made bv th.-> (Electric >'" v aiM Battery Company, em])loys antimony irrids. with button- of peroxid 1"2 MKDICAI. KLKCTKKTI Y AX1) KOXTCKX HAYS of lead on the negative and of metallic lead on the positive plate. Each cell contains several positive and several negative plates, and a cell Hi inches high and weighing, when filled with -10 pounds of weak acid, bio pounds, will give 2.~> amperes for eight hours or .'-Jo amperes for four hours, or oO amperes lor three hour-, or 100 amperes for one hour. Its potential is only 2 volts, and to obtain the heavier currents it is necessary to have several such cells connected up in series. The Edison storage battery has positive and negative plates of thin nickel steel, wit h pern irat ions in which t he active material is consolidated under hydraulic pressure. The surface of the positive plate is made up of powdered peroxid of nickel mixed with powdered graphite; the negative plate contains powdered oxid of iron and graphite. The electrolyte 1 is an aqueous solution of caustic potash. Passing a current through the cell in order to charge it converts the positive plate into hyperoxid of nickel and -the negative plate into spongy metallic iron. After discharge the grids are covered with peroxid of nickel and oxid of iron. There are a number of plates in each cell; its voltage is l.o, and it is a much lighter cell than the lead storage-cell. Faure's Accumulator. A single cell consists of two lead plates coated with a paste of minium (Pb 3 O 4 ), with dilute sulphuric acid t,II_,SO } ). The coated plates are covered with felt or cloth, to prevent contact with each other, and are rolled up together and immersed in dilute sulphuric acid. The following reaction takes place in both plates befo'j: 1 the application of any current. The sulphuric acid acts upon the minium: Pb 3 4 + 2H,S0 4 = PbO, + PbSO 4 + 2H,O. If a charging current from a battery or dynamo is now applied, there is the following result at the plate connected with the positive wire from the dynamo: Pb.SO 1 -H/J + = PbO,-fH,S0 4 . In other words, the elec- trolytic liberation of oxygen at the positive electrode results in a complex reaction, producing an additional deposit of PbO., and an increased amount of II., SO,. At the plate connected with the negative wire from 1 he dynamo a contrary effect is produced. It is one of deoxidation, and t he I'b( )., and I'bS< ), are both reduced to spongy metallic lead: the other products there being II ,SO ( and H.,O. After being completely charged, the storage-cell i< capable of giving a current of electricity if the two plate< are connected by means of an external circuit. The current will be in the opposite direction to the charging current, and has an electromotive force of about 2 volts, The reaction at each plate (luring disci large just reverse.-; t hat occurring while 1 lie battery is being charged. The care of a storage battery consists chiefly in charging and rechargintr it. seeing that it doe- not become short-circuited, and that the fluid i- maintained at the original quantity and strength. \\hen out ot -ervice tor more than a month or two the storage battery ,-hould be fully charged, washed out thoroughly with di-tilled water, arid kepi empfv of all liquid. Neglect of this care results in "sulphating" or irreparable de-triiciion of the plate- by the acid. Charging a Storage Battery.- Figure 74. . I, shows the connections to be made when the -lorage battery i> charged from the 110 volt< direct incandesceni h^h' circuit. From the po-itivc wire the current is led acro-~ a fused knife -witch to a bank of four 1(1 c. p. incandescent lamp-, arranged in parallel, and acting as a resistance, so that only the de.-in-d current .-trength of three ampere- or >o can pa-s through the DYNAMIC KLKCTHICITY 103 storage battery. From the hank of incandescent lamps the positive current is led to the positive pole of the storage battery (connecting the positive elect ric-light wire with the wrong pole of the storage battery would product 1 damage), and thence across a fused knife switch 1o the negative electric-light wire. It takes about ten hours to charge a storage battery. Figure; 74, B shows the arrangement for charging a storage battery from the o.">0 volts direct current of the trolley-car system. The difference to be noted is that the bunk of incandescent lamps consists of five parallel series of five Hi c. p. incandescent lamps each. This results in the same current strength reaching the positive pole of the storage battery, as in the case of the 110 volts direct current controlled by the single lamps in parallel. /Veoaftyf w/re * ^ -SK U ' /,,^s a foray r 74.. I. For 110 volt- direct current. Fig. 74, B. For ooO volts direct current from the trolle.v svstoin. Where the current is supplied by an alternating incandescent light circuit of 110 or 125 volts, it is necessary to have the current changed so as to be unidirectional. This is accomplished by introducing a mercury arc rectifier into the circuit between one incandescent light wire and the storage battery, with its bank of lamps t<> regulate the strength of the current. The w(vr ///// a/'c rectifier consists of a vacuum tube with a reservoir of mercury at the bottom which forms the cathode, with which one $ _ b T B&Htr/ MKI>I< AL KLKi TKHITY AND H< )NT( iKX KAYS iron anodes. The cathode in a vacuum tube has a reluctance which mu-t le overcome l>y the disintegration of its surface. And if such a tube i- -imply interposed hetween the positive pole of the storage batterv and one incandescent light wire, while the other pole of the storage battery i- connected with the oilier incandescent light wire, no current will pass. The terminal- .1 and > will remain as completely insulated as if they were separated by an inch or two in the open ail'. The surface of .1 may. however, be disintegrated and .1 be made 1o act as a cathode and permit the ilow of current- iti the direction from a. to .1. And this can lie done without disintegrating the surface of a. which remains incapable oi acting as a cathode, and t he tube will not transmit currents m the direction from .1 to a. '1'here are thus transmit ted through tlie storage battery a siicce-sion o| current.- in onlv one direction and care i- taken to have the connection made A\ith the proper poles of the, storage battery. I'lns succession of currents may be made an almost continuous current by introducing a self-induction coil at K. l^u-h lin e the current ceases to (low. an extra current in the .-a me direction .- produced by inductance. '1 he other side of the diagram shows the arrangement lor disintegrating the surface of the mercurv cathode ,1, and keeping it so, and constantly in condition to act as a cathode. - accoiiijdished by first sending an induction .-park from the other Mo . 1 . and following this up with a constant current of Ml ampere- and 11 volts, between the same points. A storage battery b supplies ' a ce the mill; IT primary discharge by means ol a .-el; e ;iiid a quick 1 ireak -wil ch. I:, liic :, ra!iL r ei > ' ' is far de-cribed t he]-e i- a direct connection ln-t'.'.-een e dvnamo circiiil and the -toi'a.U'e battei'X' U'hich is being n only ! alf : thn current: from the dynamo are utihxed in ati\ '.vay. ["in. 7'i -ho\v- an arranLrenient bv which both sets of current-; are d irect ] v bv means of secondary induct ion coils. I he va< mini hilji be pr'u ed. or t he current si a Tied through it by a .-purl, from a -toraire ba'terv and a self-induction coil. After that an induced DYNAMIC KLKCTUHITV 10.1 current is -ent through the vacuum tube from two secondary coils alternately. These two coils have the same number of similar turn-, but in the opposite direction. Currents are excited in one of these by the alternating current in the primary coil. One of the secondary coil- is connected with one anode of the vacuum tube, on the one hand, and with a self-induction coil and a storage battery and 1 he mercury cathode, on the other hand. The other secondary coil forms part of a similar complete circuit starting from the other anode of the vacuum tube. The surface of the mercury is disintegrated by a spark irom the priming batterv, and thereafter no battery current is necessary, only the sec- ondary currents; and their potential is kept from falling to zero by the; presence; of the self-induction coils. Kach secondary coil sends impulses in both directions, but only those in the direction from the anode to the cathode can pass through the mercury vapor tube. There are currents in this direction practically all the time; when one coil is not sending one. the other is. A similar arrangement is used to rectify Iriplxtw current*, the trans- former having three secondary coils. And Mr. Cooper Hewitt reports that he has succeeded in making a rectifier supplying a direct continuous current of :>0 amperes and ">()() volts with an efficiency of US per cent. A t/icclitinic reed /icr fur alternating currents !i>r use in charging storauv batteries may consist of a step-down transformer to reduce the voltage to the figure required, and an electric vibrator on the same a- all electric bell. This is regulated so that the contact is n a I 1 lie limes when t he current is Id iwinir in the same direct ion. apparatus devised by Soiilier 1 issaid to run perfect lv steadilv 1UI) MEDICAL KLKCTHICITV AND RONTC'.KN HAYS time, and not to become hot like electrolytic rectifiers. It has no liquid to be renewed, and consumes less current. Electrolytic rhown in Fig. 7s. One alternating current wire is connected with the lead of one cell and with the aluminum of another. The other iv ire of the alternating circuit is connected with the lead of the third and with the aluminum of the fourth cell. The wire which is to deliver tlii' positive current to the storage battery is connected with the alumi- num of the two cells, whose lead is connected with the two alternating current wires. The negative wire comes from the lead of the two cells whose aluminum is connected with the alternating current wires. In regard to any one cell polarization prevents the flow of the current in one direction, while offering very little obstruction in the other. At each alternation in the primary current cells 1 and ,'i take turns in allowing a current to pass in the direction indicated, and so do cells 2 and 4. The fluid used is a strong solution of Kochelle salt. A Booster. In the power- houses of the trolley-car system the storage; batteries are of tre- mendous power and are formed bv a series of hundreds of large cells and require a greater voltage than that of the line wire to charge them. So that instead of having to use a reduced voltage, small establishments, it is savy to supply a current This i: general or, which is called a boo expression for help up i ir pu.-h up. ~e of i he \vord hi niftier designates a step-up transformer for a'_!;e alternat ing cm-rent . nay be used in parallel ("multiple") or in series or a he two, just like ordinary voltaic cells. Their large ability 1 ' i recharge 1 hem con: crapeut ic \vi irk. ' necessarv when a | 'Tt a! \vork where a dvnam UlVltlli' higher vo Si i irage-eells ! coiiil iinat ion ' if 1 cat lacit v am \ t he tatres l'i ii 1 mai "I he; arc e-pc is iv i cd , it ute verv irreal ad van- THE PRODUCTION OF ELECTRICITY BY ELECTROMAGNETIC INDUCTION I' i' e' ' p irp"-e iviuiriim a lai'irc amouiit of electric current DYNAMIC: KLKCTKICITY 107 and similar generators. These all depend upon the principle that the motion of a magnet or of a coil of wire through which a current of elec- tricity is passing will induce an electric current in a neighboring coil of wire. It was natural to expect that currents of electricity in one wire would produce currents of the same general sort in another wire, hut it was a discovery of the greatest importance when Michael Faraday, in 1831, found that the motion of magnets would generate; electric currents in neighboring wires. This had been preceded and was led up to by Oersted's discovery that a current of electricity in a wire will induce magnetism in a neighboring iron or steel rod. The relation between electricity and magnetism is most intimate, and it requires only the proper apparatus to convert force manifested as electricity into force manifested as magnetism, or vice versa. There are several important properties which illustrate this relation, and which are used in the construction of apparatus for the production, measurement, or regulation of electricity for medical purposes. Directive Effect of Dynamic Electricity Upon a Magnetic Needle. A current of electricity passing through a wire causes a magnetic needle, like a compass needle, to tend to assume a position at a right angle to the direction of the current. If the wire is above the needle and the current is passing from south to north, the needle will turn with its north pole to the west. When the current passes below the needle, but from north to south, the needle will again deviate to the west. The 1 needle type of galvanometer measures the strength of the; current by the amount of deviation produced. Magnetizing Effect of Dynamic Electricity upon Iron and Steel. A bar of steel surrounded by a. coil of wire through which a current of elect I'icity passes becomes a magnet, and the question as to which end of the steel becomes the north pole- depends upon the direction in which the currcMit passes, from right to left, or vice versa. Fig. 70 represents the case 1 of a straight wire crossing above a steel bar. and the current passing in the direction indicated by the arrows The steel bar becomes a magnet with its north pole at the end indicated by N, and its south pole at S. In this diagram more clearly than m any other case is shown the truth of one rule for determining which pole of an electromagnet is the north and which the south. The r lie is that a person swimming with the current of electricity at any part oi the wire and facing the electromagnet will have the north pule at his left hand. If the arrows indicating the direction were. 1 reversed, the poles of the 1 electromagnet would also be revered. I OS MKD1CAL KLIXTKICITY AND H()NT(iKN HAYS Fiirure SI show- the po-ition of the induced magnetic poles when the wire form> a single loop passing around the steel bar in a plane at a I unit a riidit almle to its lon shows the idea of a ri^ht-liaiuU d spiral, ai.d if the ciu'rent Mow- in the direction indicated by tin 1 arrow. /'. e., in the direction of thr hand- i,f a watch, the pole touard the observer is the south pole. ' It the current \vere flowing in the opposite direct i^n. throtiji'li the same flexH'ovsal or riu'ht -handed -piral. the polarity ol the elect I'ornau'iiet \\'i iiild be reversed. riu-ure Mi -ho\\< the idea of a left-handed spii'al. and if the current flows contrary to the hand- of a watch, as indicated bv the arrow, the neare-1 the observer. If the current flowed in direction, the magnetic polarity would be reversed. 7 represent- t he ca-e of a i'im a coil consisting of one long single wire, the number of turns being regulated by the Voltage of the battery. The amount of power is illu>lrated by the fact that a horseshoe magnet made from a cylinder ten inches long and AN ill sustain a weight of fi >uri eon pounds when acted upon by t ho c from a single cell, in which t here is a xinc surface of onlv '_' : square ii > - and t ho electrolyte is a t himbleful of dilute acid. In ai tliov n experiment ;i cannon weighing .">(). HIHI pounds has been magnet i/ei] 112 MEDICAL ELECTRICITY AND ROXTCEX RAYS by ;i current of 1(1 amperes passing through 10 miles of wire, making ~)2.")0 Tunis around the cannon. This equaled 1 10.200 ain])ere turns. The electromagnet thus produced was so strong that a string of iive caniii >n-balls weighing LMO pounds a])iece hung suspended from the cannon by mutual attraction and heavy iron s])ikes remained in a horizontal ]iosition in space. The latter effect was produced when a soldier stood before the muxxle "f the cannon whh the iron spikes in front nf his body. The spikes assumed the direction of the lines of force, and were held pressed against the soldier's body in that ]>osition by the enormously powerful attraction of this gigantic electromagnet. A similar < >bservat ion may he made any time the .r-ray coil is turned on. if a piece of cardboard is held vertically, separating pens or other light steel or iron bodies from contact with the end of the soft-iron core of the coil. The pen- will remain horizontal in the air. one end attracted toward the coil and the other end repelled. This effect is not peculiar to electromagnets any type of magnet will produce similar effects. An iron <>r steel rod brought near one pole of a magnet undergoes mag- netic induction; the opposite kind of magnetism is generated in the nearest end. and this end is attracted to the pole of the magnet, while the oilier end of the rod has the same magnetic polarity induced in it as that of the neighboring pole of the magnet, and is. therefore, repelled by it. The strongest effect, of course, is produced by a horseshoe mairnet upon a rod placed across its two poles. The end of the armature in contact with the north pole of the horseshoe magnet has south pi >larity induced in it by the influence of both poles, that kind of magnetism being attracted into it by the north pole and repelled into it by the south pole. It. therefore, has a doubly strong attraction for the north p. >le of the horseshoe magnet. A similar induction of double strength occur- at the end of the armature in contact with the south pole of the horseshoe magnet. A horseshoe magnet with an armature across its end- will sustain more t iian two poles of a bar magnet act ing separately. It is -aid to be a polarized armature when the armature itself is a per- manent magnet, and. of course, must be made of steel. For most purpose? this is le-- desirable than an armature which is made of soft iron and lose- it- magnetization when not under the influence of the magnet, and having no permanent polarity of its own. re-ponds fully and freely t<> the influence of the magnet in every position. < iaiiot ("' Physics") gives the following as the results of different experiments upon electromagnetic force, and these have varied accord- ing TO the different senses attached to the term bv various observers. KlcPiromngnctic force may mean F the current which the develop- the magnetism of a soft-iron core induce in ; II the free magnetism measured hvthe oscillating at a distance: < III \ he nttnirt; ,-, r the force required to hold an ai'inat ure at a disl aiice fn mi the nagnet : (\\ i \\\u lijti'iif] /K///Y / measured by the force with which at ure is held in direct contact with the pole. os1 imp'irialU results \vhich have been arrived at are the tin DYNAMIC ELECTRICITY 113 there is, as Miiller has found, a maximum of magnetization which cannot be exceeded. (ii) Taking into account the resistance, the electromagnetic force is independent of the nature and thickness of the wire. Thus, the strength of the current and the number of coils being the same, thick and thin wires produce the same effect. (iii) With the same current, the electromagnetic force is independent of the width of the coils, provided the iron projects beyond the coils, and the diameter of the coil is small compared with its length. (iv) The temporary magnetic moment of an iron bar is, within certain limits, proportional to the number of windings. The product of the intensity into the number of turns is usually spoken of as the magnetic power of the spiral. The greatest magnetizing power is obtained when the resistance in the magnetizing spiral is equal to the sum of the other resistances in the circuit, those of the buttery included, and the length and diameter of the wire must be so arranged as to satisfy these conditions. (v) The magnetism in solid and in hollow cylinders of the same diameters is the same, provided in the latter case there is sufficient thickness of iron for the development of the magnetism. With currents below a certain strength, wide tubes of sheet iron are far more powerfully magnetized than solid rods of the same length and weight; but with more powerful currents, the magnetism of the latter preponderates. (vi) The attraction of an armature by an electromagnet is pro- portional to the square of the intensity of the current so long as the magnetic moment does not attain its maximum. Two unequally strong electromagnets attract each other with a force proportional to the square of the sum of both currents. (vii) For powerful currents the length of the branches of an electro- magnet is without influence on the weight which it can support. Beetz observed that, for the same strength of current, electro- magnetism is produced more rapidly in circuits with great resistance and great electromotive force than in circuits with small resistance and correspondingly smaller electromotive force: in the latter case, the reverse currents which occur in the coils of the electromagnet come into play more than in the former. During magnetization the volume of a magnet does not vary. This has been established by placing the bar to be magnetized with its helix in a sort of irate r thermometer, consisting of a flask provided with a capillary tube. On magnetization, no alteration in the level of the water is observed. But the dimensions vary: the diameter is somewhat lessened, and the length increased: according to Joule, to the extent of about .,-,',,,,7] if the bar is magnetized to saturation. As regards the quality of the iron used for the electromagnet, it must be pure, and be made as soft as possible by being reheated and cooled a great many times: it is polished by means of a file, so as to avoid twisting. If this is not the case, the bar retains, even after the passage of the current, a quantity of magnetism which is called the remanent magnetism. A bundle of soft-iron wires loses its magnetism more rapidly than a massive bar of the same size. According to Stone, iron wires may be materially improved for electromagnetic experiments In- forming them into bundles and tying them round with wire: these bundles are then dipped in paraffin which is set fire to. 8 114 MEDICAL ELECTRICITY AND RONTGEN KAYS "Remanent magnetism is greater in long magnets those, that is to say. in which the diameter is small in proportion to the length. It is decidedly greater in soft iron when the magnetizing current is not opened suddenly, as is usually the case, but is. gradually brought to zero by inserting successively greater resistances. By suddenly opening the circuit it has occasionally been found with thick rods of very soft iron that a reversed remanent magnetism is met with, which is called abnormal magnetization. " This is easily understood from the tendency of molecular magnets to revert to their primitive condition. In doing this they experience a certain friction or resistance, and when the magnetization gradually diminishes, this hinders the complete reversal of the molecules: but with a sudden cessation the molecules, from the greater vis viva of their reversal, will sooner come back to their original position, or even pass it. and come to rest on the opposite side." Ampere's Electric Theory of Magnetism. This theory is that in iron or steel there are electric currents in motion around the atoms or in the atoms, and that when these currents are polarized or all made to flow in the same direction the iron or steel becomes a magnet. Except at the surface, these currents are supposed to neutralize each other. Fig. 91 illustrates Ampere's theory of magnetic induction by an electric current. Fit'. 91. AnipfTf':- tin >f magnetism. Klcctrio Currents about the atoms oausrd to itr-sunic the .-ami- direction. Magnetic Inertia or Reluctance. An expenditure of energy is required to cau.-e all 1 he currents theoretically present in an unmag- netized bar of iron or steel to flow in the same direction and make the bar of iron a magnet . or. on the other hand, to reverse the polarity ol a magnet. Both of the>e processes take time, and so does the return ol a soft-iron electromagnet to the unmagnetized slate. The magnetic effect is not instantlv produced when the electric current is turned on or off. but there is a certain magnetic inertia or reluctance to be over- e. This is of no consequence in the case of an electromagnet which is to be u.-ed for some time continuously without a reversal of polarity. The large electromagnet u>ed for the extraction ol steel panicle- from the eveball i- one of this sort. But in the ca.-e of the DYNAMIC ELECTRICITY 115 electromagnet which forms the core of the primary coil of an induction coil, it is necessary that the magnetic inertia should be reduced to the lowest possible amount, so as to enable it to become a powerful magnet the moment the electric current is turned on, and then completely to lose its magnetism the moment the current is turned off. The breaking of the circuit may be accomplished by the action of the electromagnet itself pulling the armature away from contact, or it may be done by some extraneous means. In the latter case, the minimum magnetic inertia is required for the proper induction of currents in the secondary by the action of intermittent currents in the primary coil. The minimum magnetic inertia is obtained by making the soft-iron core a bundle of straight parallel wires; and for an x-ray coil, for instance, these wires are about the size of piano wire, and form a bundle two or three inches in diameter, and about twice as long as the spark-length of the coil. Another way of reducing the magnetic inertia is by making the electro- magnet of many thin sheets of soft iron bound together, and this is designated as a laminated magnet. The powerful magnets of electric motors are often made in this way. The Properties and Effects of Magnetic Flux. Electromagnetic waves in the universal ether are what this flux really is. They have the same velocity in free space as light, and are subject to the same variation in velocity when passing through different media. The index of refraction of a substance for light is closely related to its magnetic permeability. The magnetic flux rotates the plane of polarized light if the polarizing substance is in a magnetic field, and it also gives the property of polarization to some substances which do not ordinarily possess it. The Hertzian waves used in wireless telegraphy are elec- tromagnetic waves. The flux from a magnet has the power to produce magnetism in other iron or steel bodies in the neighborhood, without loss of its own power. The magnetic flux also exerts an attraction or repulsion upon such bodies and upon wires through which a current of electricity is passing. Variations in magnetic flux produce currents of electricity in wires in the magnetic field, and this is to-day the most important source of electricity, and is the reason why it has been necessary to state so many of the facts in regard to magnetism. A coil of wire placed with its turns in a horizontal plane and open at the top and bottom, and traversed by a current of electricity, exerts an attraction upon an iron bar placed within its lumen. The bar may even be held suspended in mid air by the invisible attractive force, not being in contact with any part of the coil, but simply inside the opening along its axis. If the bar is pulled a little distance in either direction, the attraction will bring it back to its position inside the coil. The mutual attraction existing between electric currents and magnets is the force concerned in electric motors and dynamos. (See also p. 119.) The Attraction Between Electric Currents. Two active loops of wire freely suspended tend to place themselves in such a position that their plane surfaces are parallel with each other and the cm-rents flow in the same 1 directions. The laws governing the matter are that (1) Two currents, parallel and in the same direction, attract each other. (2) Two currents, parallel but in opposite directions, repel each other. The north pole of a magnet will be attracted by the end of an active IK! MEDICAL ELECTRICITY AND RONTGEN KAYS helix which lias south polarity, and will be repelled by the end having north polarity. In the case of either the iron bar or the magnet being fixed and the active coil (win 1 through which an electric current is passing) being freely movable, the same attraction or repulsion will be operative And this will cause the active coil to move into such position that the rela- tions between the coil and the magnet or iron bar are the same as if the latter had been movable and the coil stationary. If one active coil is stationary and the other freely movable, the latter will move toward the former if the currents are both in the same direction, or away from it if the currents are in contrary directions. Production of Electric Currents from Magnetism. If one pole of a magnet is brought near a coil of wire which is not connected with any battery 07- other source of electricity, a current of electricity will be generated in the wire. This may be demonstrated by connecting the two ends of the wire with the terminals of a galvanometer. The arrangement in Fig. 92 illustrates the principle involved. The magnet being moved Toward and into the lumen of the coil, a current of elec- tricity will flow through the wire and be indicated by the galvanometer during the motion of the magnet. A current will flow in the opposite direction while the magnet is being withdrawn. Xo current will flow through the wire while the magnet is stationary either near to or far from the coil. The direction of the current through the coil varies according to which pole of the magnet is near the coil and whether it is being moved toward or away from the coil. The arrows in Fig. 92 indicate the direction of the motion of the magnet and also of the current: and the letter- X and S indicate the north and south poles of the magnet. |o represent the effect of withdrawing the magnet, it would simply ! necessary to reverse the posuion of all the arrows representing the direction jn \\-hich the magnet moves and the current flows. I'ig. 9)j shown the direction of the current produced when the north pole of a magnet is moved toward a coil. And in this case also the direction of the current is reversed if the magnet is moved away IT' MM instead "f 1< iwan i 1 he n >il. An electric current is produced at the same moment and in the Same direction i; the pole of the magnet is moved luterallv across the face or end of the coil instead of into it. The current will be in the direction indicated in the la-t diagram 'Fig. 9:]i. while the north pole i- moving toward the axi> of the coil or the central line passing through DYNAMIC ELECTRICITY 117 the hollow of the coil at a right angle to the planes of its various loops. After the pole of the magnet has moved past the axis of the coil and begins to move away from it, an electric current in the opposite direc- tion is generated in the coil. The currents produced by moving the south pole of the magnet laterally across the face of the coil are the Fig. 93. Direction of the current when the north end of the magnet is moved toward the coil of wire. same as those produced by moving the same pole into or out of the coil, as shown in Fig. 93. Magneto-electric Machines. The same currents are generated in all these cases if the coil is moved instead of the magnet, as is the arrangement in the magneto-electric machines (Figs. 94, 95, and 9(i) which were the predecessors of the modern dynamos and which are still used in therapeutics to some extent. Taking into consideration only one of the coils of win', as that is rotated toward the north pole of the magnet, a current will be generated in that coil which will be in the direction of the hands of a clock if the coil is viewed from the end facing the magnet. At the same time that this coil has a rotary motion toward Fig. 04. Magneto-electric machine f<>r therapeutic use. the north pole it is moving away from the south pole of the mag- net, and the electric current resulting from this is in the same 1 direction. After this coil passes the horizontal line, however, it begins to move away from the north pole and toward the south pole, and the direction of the current flow is reversed, so that a regular alternating current is generated and may be transmit tod to a circuit outside of the machine by having the two extremities of the wire connected with two insulated revolving metal collars, against which press two springs or bn:>hes conducting the current to the external circuit. The other coil i- re- ceding from the north pole of th'- magnet at the time that the one 118 MEDICAL ELECTRICITY AND RONTGEN RAYS first considered is approaching it, and consequently it is necessary that its wire should !' wound in the opposite way to make it yield currents in the same direction as those from the first coil. The coils are both con- nected with the external circuit by the same metallic collars and brushes, and reinforce each other in delivering an alternating current. Fig. 95. Clark's magneto-electric Ren- orator, 1500 turns in cadi coil rotated in front of magnet (laminated). Fig. 96. Rotated so as to cause upper portion to come toward observer, current would go as shown by arrows. After a half turn it would be reversed. The Commutator. This is an important part of any machine for the generation of dynamic electricity by electromagnetic induction. It is a device for converting a series of alternating currents into a series of unidirectional currents passing into the external circuit. In its simplest form (Fig. 97 and 98) it consists in having the wires from the coils terminate in the two halves of a metal cylinder which is completely divided into two longitudinal halves, fastened upon an insulated shaft and rotating with the coils. Each brush leading to the external circuit Fig. 97. Commutator. Fig. 9X. Diagram of the commutator in operation. is in contact with one of the halves of the split cylinder and receives current from it. Calling the sections of the commutator jpe is required, which means that the magnetic flux or lines of force passing out of the magnet at the north pole traverse only iron on their way to the south pole. This is accomplished in certain cases by making the magnet in the form of a horseshoe, and placing an armature across between the two poles. The horseshoe shape may lie only figurative, as in the case of a very useful type of electric motor (Fig. 99 1. where 120 MKDK'AL ELECTRICITY AND RONTGEN RAYS there is a heavy iron base' from which two uprights extend; the latter have large concave surface's facing each other, and called polar surfaces. Between the polar surfaces and very close to them is the revolving arma- ture of the motor. The 1 stationary part is made a powerful magnet by an electric current passing through coils of wire surrounding each iron standard. It will be noted that it is not necessary that the polar surfaces should be at the ends of the arms of the horseshoe. Kxcept for the small air-space between the polar surfaces and the armature, the magnet represented above is of the ferric type. One of the absolute ferric type is a horseshoe magnet with an iron armature across its ends, and another is an iron ring magnetized by an electric current passing through a coil of wire which surrounds the wire at one part of its cir- cumference. The first of these types of complete ferric magnets is often adopted as a means of guarding against the gradual weakening of a permanent magnet and, of course, is the case where an electro- magnet is used to lift or to sustain a heavy weight. The second or closed magnetic ring forms part of the step-up transformer for the induction of high-tension currents in a secondary winding by alternating or interrupted currents in a primary wire; or of the step-down trans- former, which induces currents of reduced potential in the secondarv wire. For this purpose again the closed magnetic ring may be only figuratively a rim:. Very often it is made up of laminated rectangles of soft iron, riveted toget her at i he corner.-- and surrounding a rectangular opening. 'Ihe closed magnetic ring has a verv much higher rate of efficiency in tin- production of induced, currents than has the other type of induction i-nil with a straight iron core. Mill/in in- jli/.r is i hr> force bv which steel and iron are attracted toward magnets, and by which electric currents are generated from the use of maLMiet^. It is proportional to the magnetomotive force, and inverselv to the magnetic resistance of the circuit (ferric, aeroterric, or non-ferric) or the magnetic reluctance. The practical unit of magnetic flux is the //V ,.,;, sometimes consist of flat brass springs which press upon the commutators and come in con- tact with the different commu- tator sections and the insulating strips as the axle revolves. In large dynamos the brushes are rectangular pieces of carbon or brass held against the revolving commutator by the pressure of a spring. Series-wound and Shunt-wound Dynamos. A dynamo in which the entire cm-rent induced in the armature coils passes through the winding of the field-magnets is called a series-wound cli/tKinio (Fig. 100), and thi- arrangement tends to maintain a uniform strength of current, or the >ame number of amperes, no matter how great or how small is the resistance in the external circuit. This sort of a dynamo is used when the current is produced expressly for the operation of a number of arc liu'hts connected up in series. The number of amperes which nnM pass through each arc light is from (i to 10. The re.-islance of ;iii arc lump is -uch that it takes 12 to .72 volts potential to send this current iliroiiirh one lamp. For a number of arc lamps in series the voltage HUM be multiplied by the same number, in order to send the -ame -trenii'th of current through the series of lamps. This is accom- plished automatically by a series-wound dynamo. A series-wound DYNAMIC ELECTRICITY 125 elynamo may bo calleel a constant current dynamo. This is true 1 up to the 1 capacity of the 1 engine in horse-power. Beyonel that the elynamo woulel fail to drive any current through a scries of are- lamps. A xlmnt- iroiind dynamo (Fig. 101) is called a constant potential dynamo, and is elosigned to yie'lel a current of the same 1 voltage uneleT varying e-eniditions of the external circuit. In such a elynamo the winding of the hVlel- magnets consists of a groat many turns of fine 1 wire having a resist- ance about four hundred time's as gr(>at as that of the 1 armature coils. Starting from the positive 1 brush, the 1 cunvnt passes through a eliviele'el path, erne 1 part ge>ing to the external circuit and the 1 other to the wineling I'ifl. 101. Shunt-wound dynamo: / Rheostat rejrulates proportion of the t \v< current paths. of the field-magnets. The return currents from the field-magnets and the external circuit join before they reach the negative brush. The currents which pass through the two dif- ferent paths are inversely proportional to the resistance in each. If the external resistance is increased, a greater proportion of the current passes through the field-magnets, and this increases their strength and the current output of the dynamo. The reverse 1 takes place when the external resistance is diminished. The result is a uniform voltage under most conditions. Compound-wound Dynamos. These are dynamos in which part of the current to the external circuit passes through the field-magnets and a portion does not. They are designed to yield a uniform voltage under all conditions from no load to full load. The 10,000 horse-power dynamos at Niagara Falls are of this type. In any dynamo the electromotive force or voltage increases with the speed, the strength of the field-magnets, and the number of conducting loops in the armature. Gramme's Ring Dynamo. This is an important typo of dynamo, in which a soft-iron ring revolves like a wheel on its axle, its rim being close to the two poles of an electromagnet concaved so as to bring the polar surface's as ne>ar as possible to the ring. The latteT has a winellng of many turns e)f insulated wire, making an ewlle-ss coil around the 1 rim of the' wheel. The 1 ring being rotated in the direction indicated by the arrows at the 1 axle in Fig. 102, oloe'trie- e-unvnts will flow through the armature 1 in the direction shewn by the 1 small arrows. Commutator sections are 1 arranged to connee-t with the 1 armature 1 at the 1 points midway between the pole's e>f the magne't, and the erne 1 markeel -f- is the positive 1 pole, and the one 1 marke-d is the 1 negative* pole 1 of the 1 dynamo. The 1 current is "direct," and is almost e-ontinuems. As actually constructed for use as a hand gcneTator of oleM-trie-ity (Fig. 103) th (> magnet is a powerful one of horseshoe shape 1 , and made 1 of laminated stevl. The armature consists of thirty e-oils, eae-h having a large 1 number of turns of line' wire. One end erf each coil is connected with the 1 aeljacenit e'nd of the ne'xt e'oil, and also with a e-ommutator section. The 1 coils thu- f'orm a continuous e-ircuit, tappexl at intervals by the 1 commutator -ections. The 1 armatun 1 core 1 is made up of a number erf soft-iron wires forming a continuous ring. A hand machine of this kind vields 126 MEDICAL ELECTRICITY AND RONTGEN RAYS a potential of about three or four volts, which is about the same as is yielded by three or four Dauiell cells. The current is a strong one, and a hand machine could be used for cau- tery purposes or for exciting a faradie coil. But for most electrotherapeutic work the choice lies between a battery . either primary or secondary (storage), and a power-driven dynamo. m. 1()L'. --( iramme's rin would have the maximum strength, and such a direction that (i would be the positive and b the negative pole. Conductors leading from c and '/>!'- I'h'ist Current-*. As far as concerns the two wires of any particular circuit from a triple phase generator they transmit simply a regular alternating current, usually of sixty cycles. And it is only when the three pairs of wires lead to three related but not necessarily contin- uous parts of th" same electrical machinery that the advantage is seen. Comp(iri*on Between Mechanical Movement find Triple Plntxe Cur- rent.*, -Figure 107 shows three engine pistons (P, P 1 . P-) connected by toggle joints with three different parts of the circumference of a wheel which they are to rotate. A cycle for P- would carry it from its present position at the forward end of its excursion to the back end of the cylinder and attain to the forward end. All three pistons go through similar cycles, but at times differing from each other by ^'f.' ( \ of any cycle; or 120' as a rotation of the wheel takes place in any cycle. P- in the diagram is obviously at a place where it cannot apply any rotary force to the wheel. In mechanical parlance P- is at a dead center, and if it were the only piston there would be two points in each cycle where no rotary power would be applied by it. A single piston moving back and forth would !>- analogous to an ordinary alternating current. With three pi-ton- 120 J apart, as in the diagram, two of them are exerting rotary power even when one is at a dead center, and there is never a moment \vh<-n there is not a very great efficiency in the application of condition is analogous to the mechanical advantage of i a s ; > f .*< "/ 'I npli l*h. Triple phase current curves. There is alwavs effective current in at least tw<. supplies an external circuit independently. This method is not com- monly employed. A gamma (/) connection with a common return wire has one end 9 130 MEDICAL ELECTRICITY AND RONTGEN RAYS of each of the three coils connected with a neutral wire. Each external circuit is connected with this neutral wire and with a wire going to the other end of one of the three coils. The star or gamma (/M connection has one end of each of three coils connected at a neutral point X. The other end of each coil has a line Fit:. lO'.K Triple pha.-e currents. S^tar or Y distribution with a common return wire. LINE A Fig- 110. Triple phase currents. Star or Y distribution without a return wire. leading from it through a separate circuit of lamps, for example', to a common neutral point Y. from which no re-turn wire is requiivel. In the delta connection the- coils are connected in such a way as to form a complete circuit, and le-ad wire's start from three- of the- junc- tions. Any two of these lead if\ wires may supply a set of elec- p trie lamps or elertric motors. < It looks as if all but a small \ amount of the 1 current gener- , I ate'd would pass through the \^ ^-^ circuit formed by the 1 coils and Fin. 111. Triple plmse currents. Delta very little- would go through rlistribution. Kach set of lumps receives power the thive external e'ircuits with their greal resistance^ But as a matter of fact this is a ve-ry effective- way of applying electric power. If the current instead of sixty cycle's a seremd had about a elozen cycles a minute we should be- able to see each set of lamps in succession UTadually liu'ht up and then gradually go out entirely. And if 1 he-re were meter,- in serie- with the lamps each meter in sueression would .-ho\\ a gradual increase of current in one direction, then a gradual re- duction to zero, then a gradual increase in t he either direct ion. and again a gradual ret urn to zero. YY''///< />hd.-i currt-nlfi form the 1 primary current in the author's generator of his . A /ml i//>//a.--i /I I///H I/in ma\' be absolutely tVee from sparks, and may not have any uninsulated surface anywhere 1 . It may be made with- out commutator- or bru-lie,-. The field-magnets may be powerful per- manent magnet.-, with completely insulated short-circuited windings, DYNAMIC ELECTRICITY 131 in which currents of the proper direction are induced by the currents in the armature coils. The ring armature is stationary, and the four or more conductors leading from it have soldered connections with its coils, and the whole may he insulated. The points a and b and c and d are stationary, but the current flow in consequence of the rotation of the field-magnets is the same as if the armature was revolving and the fields stationary. The 4 same absence 1 of movable contacts and of conse- quent sparking is found when the polyphase currents are utilized for operating a motor or a rotary converter. It makes electric power avail- able in mines and factories, where the slightest spark would cause a dangerous explosion. Polyphase currents are directly available for the operation of motors, while ordinary alternating currents are not. They are also of the greatest value commercially for the transmission of power in the form of electric currents. The power transmitted is represented by the number of watts or the amperes multiplied by the volts, and since the heating effect upon the wire is practically dependent solely upon the number of amperes, the amount of copper required is much less with a high voltage and low amperage than with a low voltage and great amperage. The transmission of triphase currents at 6600 volts costs less than 1 per cent, as much for copper conductors as the transmission of the same amount of energy over the same distance in the form of a oo() volts direct current. The higher voltage is conse- quentlv employed for the transmission of electric power for long dis- tance's, as from Niagara Falls to neighboring towns. The insulation must be very complete, first, to avoid expensive leakage of current under this high pressure, and, second, because accidental contact, direct or indirect, with a current of this character could hardly fail to be fatal to animals or men. Indeed, even in the power-house, where this current is converted by transformers and rotary converters into the o'K) volts direct current supplied to the trolley line, the workmen are liable to develop obscure nervous disorders. These occur without any accidental contact with the conductors, and are not due to leakage of current, but to the influence of expanding and contracting lines of force. That there should be an effect upon the men is easily understood when we consider the physical and physiologic effects produced by proximity to an Oudin resonator or a D'Arsonval transformer (both of them employed therapeutically), without actual contact or sparking. Accidental contact with the oo() volts direct trolley current may be fatal to men, but is not always so. It usually is to horses, partly on account of their iron shoes, while men are partially insulated. A trolley wire may become an especial source of danger if it comes in contact with a wire carrying the electric arc-light current. Polyphase currents are useful therapeutically if the proper voltage. amperage, and periodicitv are provided. A case will be referred to in greater detail in which progressive 1 muscular atrophy was cured by baths through which triphase currents were passed. This treatment sinusoidal voltaic current, and they are both an improvement on the direct voltaic current interrupted at irregular intervals by hand for t herapeut ic purposes. A Rotary Converter. --This has been alluded to, and is a motor and dynamo combined. It is used for the conversion of cue type oi current into another, and may be constructed to yield an alternating or a direct current, or a polyphase current, and of any ordinary voltage. i;$2 MKDK'AL KLECTRR'ITV AND RONTCKX HAYS But extremely high voltages must he obtained by the use of a step-up transformer. A small apparatus of this type may be used to produce the sinusoidal voltaic current, and indirectly the sinusoidal faradic currents, which are so distinct an improvement in the therapeutic application of voltaic and faradic currents. The current strength and direction should vary, as represented by a sine curve in geometry. In other words, they should produce a current starting at zero and gradually reaching a maximum in one direction, diminishing gradually to zero and then in- crea>ini- gradually in the other direction, and then gradually diminish- ing to zero, as in the apparatus employed by the author. The ap- paratus alluded to is a combination of a variable resistance and pole- clianger actuated by an electric motor (p. 4M'. What is required for some pui-poses is a current varying u'raduaily from maximum to mini- mum, and then with a reversed polarity, each complete cycle taking about two seconds: the current strength or amperage to be regulated by a rheostat in circuit with the patient. Power of Continuous Current Dynamos, The electromotive force is proportional to the intensity 0 revolutions a minute 1 ; the current being of 110 volts and '.>}() amperes. About 70 per cent, of the power employed to run the machine is actually utili/ed in the per cent, of the power is converted into elec- varii His THE INDUCTION OF DYNAMIC ELECTRICITY BY ELECTRIC CURRENTS There are two principal ways in which a cm-rent of electricity pas.-ing through a coil of wire will produce a cm-rent in a neighboring coil of wire. In the first place, an active coil or one through which a current is pa.-sm< may be moved toward and awav trom the other coll. and excite currents in it just as a magnet would. The same effect is produced if the act \\ e coil is st at lonarv and the other moves. In either case the lines of force about the active coil are analogous to those about a magnet, and the currents produced in the other coil are due to the t urn- in the other coil cut t ing t h rough 1 hese lines ot torce in consequence of the motion of one or other coil. This method of action is tullv ill list rated in t he dynamos which have been described, and in which the armatures and field-magnets consist ot coils oi wire which are no less important than their iron and steel core.-. The other principal method is by induction, by which variable - - in one stationary coil excite currents m another stationary coil. Induced Currents. It has alreadv been stated that a continuous DYNAMIC ELECTRICITY 133 current passing through one wire does not produce a current in a neighboring wire if the wires are both motionless. But it is a very different matter when the current starts or stops or varies in strengt.li or direction. Kvery such change in the active wire results in a tem- porary current in the other wire. The simplest case, and one which shows the principle upon which the entire system of induced currents is founded, is that of two straight parallel wires near each other in the air. When a current of electricity is turned on or begins to flow through the first wire, a momenta]'}" current flows through the second wire and in the opposite direction. While the current is flowing uniformly in the first wire, no current flows through the second Avire. When the current is turned off in the first wire, a momentary current is produced in the second wire, and this is in the same direction as the current which has just ceased to flow through the first wire. Changes in the strength of the current in the first wire produce similar effects; an increase in current induces a current in the opposite direction in the second wire, while a reduction in current strength in the first wire induces a current in the same direction in the second wire. An example of the practical application of the induction of currents in parallel straight wires is seen in the process of telegraphing from a moving railway train. In this case the series of dots and dashes in the Morse alphabet are transmitted as a series of interrupted currents passing through a wire fixed along the top of the car. Along the railway is a wire running parallel with the one on the car, and as near as prac- ticable to it. The currents of electricity in the wire on the car induce currents in the stationary wire which actuate telegraphic instruments at any reasonable distance along the line. This is due to simple induc- tion, and is not the same as what has become known as uirelexs tclcg- r(tph;/. and which will be alluded to again in another part of this book. Induced currents are due to the expanding and contracting lines of force about a wire through which a current of electricity passes. The inducing force is the same as in the case of induction of an electric current by the motion of a magnet; and in this case the relation between the inducing and the induced currents may be very simply expressed as already mentioned. The following are the. /cnr* of induced current*: 1. At the instant when the primary current begins to flow or to increase its intensity, an induced current, inverse and momentary, is developed in the secondary coil or circuit. 2. The primary current approaching the conductor gives rise to an induced current in the secondary coil, inverse and momentary. .'>. At the moment this current ceases, or when its intensity dimin- ishes, or when the primary coil recedes, an induced current begins in the secondary coil or circuit, direct and momentary. The Induction Coil. --This is in practical use for a hundred different torms dt elect rot herapeut ic apparatus, as well as for commercial pur- poses. It consists of a primary coil, a secondary coil, an interrupter, and sometimes a condenser. It is supplied with an electric current by a voltaic battery, a storage battery, or a dynamo circuit, like the electric-light system. It yields a succession of induced currents which are usually ot very different potential from the primary current, beinir oi much higher voltage for most therapeutic purposes. And these induced currents are of an alternating character. 134 MEDICAL ELECTRICITY AND RONTGEN RAYS The Primary Coil. The coil of wire through which the current supplied by the buttery or dynamo passes is called the primary coil, and the current through it is called the prunarij current. The primary coil usually consists of a small number of turns of rather coarse copper wire, which is insulated by a wrapping of cotton, and which is wound in a single or a few complete layers covering the outside of the bundle of iron wires which form the core of the primary coil. The two ends of this coil are indirectly connected with the battery or dvnamo. "NY hen the electricity is turned on, the primary current is said to be made; and when the electricity is turned off, the primary current is said to be broken. It will be seen later that the currents induced in the secondary coil occur in consequence of the making and breaking of the primary current, and that they are called, for convenience, the make and break current*. The break current is the more powerful, and for x-ray work is the only current desired. Two circumstances in regard to the primary current may interfere with the most effective production of the break current. They arc both produced by self -induction in the primary coil. This acts especially to induct^ a break current in the primary, which forms a sort of con- tinuation of the primary current, and is in the same direction: and then again this induced break current in the primary is of higher voltage than the primary current, and causes an electric arc at the interrupter where the current is broken. Both of these circumstances interfere with a sudden and complete breaking of the primary current, and must be overcome or regulated in order to secure the best results. Self-induction in the primary coil is illustrated very well by the simple coils, without any secondary coil, which are used to light the gas in theaters and other places where it is inconvenient to apply a match to every gas-jet. If the current from a dry-cell battery be passed through a simple coil of wire and then be quickly cut off or bn>ken. a current is generated by self-induction which has such high voltage that it will leap across the spark-gaps at all the different burners and ignite the gas. The original current from one. two, or three cells of a drv battery, if passed through a short straight wire, will produce a liny, almost invisible, spark across a very small fraction of an inch at the switch as the contact is broken. But if the wire be a long one and the switch when the current is broken may be even a third of >ng. A self-induction coil may be used for tin 1 same purposes coil, exciting muscular cont ract ion and the ot her physiologic it w< >u Id not be so good or so convenient as an induct ion coil with both primary and secondary windings. The presence of an iron add.- very much, indeed, to the strength of the secondary current, it has long been considered a necessary part of an induction coil. is not the case, however, and recent observations bv Lewis Jones show that equally beneficial results with less discomfort to the patient are obtained from a faradic coil without an iron core. If the self-induction from a .-mall coil and a couple of dry-cells produces .-park enough to light a great number of gas-jet-, it is easy to understand that the self-induction in a large primary coil like that of an ./'-ray machine, actuated by the currei (ells or a large -torat^e batterv or a dvnar DYNAMIC ELECTRICITY 1.5.) to produce an electric arc between the contacts. Arcing at the switch must be prevented because the intense heat will injure the switch and mav set fire to neighboring objects. \Yith the heavy currents employed for x-ray work the current should never be turned on and off by the ordinary key switch of the electric-light socket. If such a socket is used, there should be an open knife-switch near the coil, and this should always be turned off before the connection is either made or broken at the lamp socket. There is thus no current passing when the lamp socket key is turned on or off, and consequently no arcing there. It is better still to have the feed wires pass directly to the knife switches without the intervention of a key socket. Even at the knife-switch precaution should be taken against the formation of an arc. This will not occur if the switch is opened very quickly, and special switches (Fig. 112) are made to accomplish this. They arc closed just like an ampere:- ordinary knife-switch, but the portion of the blade which engages between the 1 two springs with which it makes a contact is hinged, so that it remains held in position by friction as the switch is opened until the strain on a spring between the rest of the blade and the hinged portion becomes great enough suddenly to draw the latter out from between the two clutches. An instantaneous break like this is not liable to produce an arc. Xo special arrangement for making a quick contact is necessary. 1'ntil the contact is made we have only the 110 volts potential to deal with, and this will not leap across any appreciable ^pace, perhaps only y,',,-, inch, as one metallic connection is brought toward the other. There is no current flowing through the primary coil, and so no self-induction is operative* until after the contact has been made. The make spark at the switch which turns on the primary current requires, therefore, no consideration except for the fact that it will ignite inflammable explosive gases if they are present. The 13(5 MEDICAL ELECTRICITY AND RONTGEX RAYS break spark at the primary switch is due to the self-induction in the primary coil, and when the 1 10 volts current is used to excite an x-ray coil, this spark is a powerful one. It is of importance because of the tendency to produce an arc between the terminals, and this corrodes the two metal surfaces and makes it difficult to press the knife of the switch into the slot between the two springs where the contact is made. It also produces danger of fire, and the switch should always be mounted on a slate or marble base, and care should be taken to keep inflammable substances out of reach. There is the possibility of an arc forming across the whole space when the switch is turned off and the current continuing to flow across the space as an electric arc. This would most effectually ruin the switch by fusing the metallic terminals. To obviate this possibility the terminals should be placed so far apart that it will be impossible to strike an arc between them. A l;tii/(-irilclt intended to turn off and on a primary current of 110 volts and up to 3o amperes should not have a space of less than 1| inches between any of its stationary metallic terminals. In practice it is not usually necessary to have a quick break attachment, but it is necessary to have a knife-switch instead of the ordinary key, such as is used to turn an incandescent lam]) on and off, and care should be taken to open the switch quickly every time that the current is turned off. In the case of a portable outfit carried to a patient's home and connected with an electric-light socket, an ordinary key receptacle, there should be a knife-switch on the x-ray apparatus, and this should be open while the attachment is made at the electric-light socket. The x-ray apparatus should not be in con dit ion to operate while the connection is being made or broken at the elec t ric-light socket. No current should be flowing when the electric-light key is turned off, and care should betaken to see that the knife-switch on the x-ray apparatus is turned off before the electric- light key is turned either on or off. When this is done, it will be found that the heavy current will be carried all right by a lamp receptacle in which the contacts are good, while it would very probably burn out the contacts to turn a heavy current on or off at this point. Properly used, the lam]) socket simply brings the supply of electricity to the knife- switch of the x-ray coil, and it is imperative that the latter should be the place where the current to the x-ray coil is turned on or off. The same self-iiu luct ion in the primary produces the little spark which is always seen between the contacts where the primary current of a laradic battery is made and broken. The spark makes it desirable to have the contact s made of platinum or some ot her met al which is not easily corroded. P>ut with the weak currents employed for this purpose, sometime- supplied by a single drv-cell. no special precautions need be taken except to keep inflammable gases awav from it. The 1 Id volts direct current, if not interrupted, could be drawn out into an arc several inches long if a current of a good many amperes had been flowintr. and it' the contacts were separated slowly. The current is practicallv completely broken bv the \Yehnelt interrupter, however, and no .-park or arc can last more than an exceedingly small part of a second as the .-witch i- opened. A break in the circuit occurs at the platinum point immersed in the liquid, and when a good contact is reestablished at that point, the metallic contact at the switch has been completely broken. Kven though there mav be a break spark at the switch from -elf-induction in the primary, the .-park is of only momen- tary duration when the Wehnelt or other good interrupter is used. DYNAMIC ELECTRICITY 137 With ordinary care about making a quick bmik one may use an ordinary knife-switch for interrupted currents as strong as 25 amperes, with no other inconvenience than the occasional necessity for filing the contacts smooth where they have been fused. This does not at all mean, however, that it is safe to turn a current of this strength on and off by means of an ordinary electric-light key. The electric-light socket may cany quite a heavy current if there is a knife-switch at the coil which is turned off both when the electric-light key is turned on and when it is turned off. In this way the electric- light key connects or disconnects the knife-switch with the source of supply, but does not itself turn the current on or off. Recurring to the subject of self-induction in the primary of an rr-ray coil, it must be seriously considered in the construction of any type of interrupter for making and breaking the primary current hundreds or thousands of times a minute. With a current strong enough to do the best x-ray work, it is difficult to do this by any apparatus which makes and breaks the contact in the open air, although there arc interrupters of this type which work well with moderate currents. With the most powerful currents, no open-air interrupter will accomplish the result: there will be arcing, and the current flow will not be inter- rupted. Generally speaking, the self-induction spark makes it necessary to use either a mechanic interrupter in which the metallic contact is made and broken beneath the surface of some liquid or gas which sup- presses the arc, or a liquid interrupter of the Wehnelt or of the Cald- well-Simon type, in which the two metal terminals arc always wide apart, and the interruptions are due to an effect of the current itself in flowing through the liquid. The self-induction in the primary of an .r-ray coil makes it act like a choke coil. With the same conditions in every respect, except that in one case there is great and in the other little self-induction, the current strength which will pass through the primary coil is markedly greater when there is little self-induction. A Choke Coil. If a coil of wire forms part of an electric circuit through which an alternating or an interrupted current passes, the self-induction in the coil may be so adjusted as to impede the flow of the current to almost any desired extent. A coil made for this purpose is called a choke coil. The impedence which it offers is not analogous to friction, as is the impedence offered by a thin straight wire to the passage of a continuous current. In the case of ordinary resistance the reduction in current strength is accompanied by the heating of the conductor and to that extent there may be a loss or waste of power by the conversion of electrical energy into heat. A choke coil, on the contrary, will reduce the amount of current flow by an inductive 1 action without proportionate heating. If ordinary electric resistance is likened to friction, then the impedence offered by a choke coil may be likened to that of an opposing force exerting traction in a direction opposed to the force by which a body is being moved. Where it is applicable, self-inductance is preferable to resistance as a means of reducing or regulating current strength. It obviates the danger of fire and the wear and tear on a resistance coil from the heating effect of the current, and is much more economic of electric cnergv. Self- inductance so arranged as to produce a choke coil means that in regard to any individual turn when the current is made it induces in all the neighboring turns a current in the opposite direction, and that the mutual 188 MEDICAL ELECTRICITY AND RONTGEN RAYS, relation between the original potential, which tends to send a current: through all the turns of the coil, and the counter electromotive force developed by inductance in the turns of the coil is such as to reduce the strength of the primary current to a certain definite extent. Impedence by self-inductance produces a tendency to side flashing. Take the case of a choke coil ami a 1 10 volts interrupted direct current, the coil being so wound that a current of only 11 amperes will flow through it. Then the two wires leading to the coil must be kept wide apart, because there will be a tendency for an induction spark to flash across between them. Xo such tendency would be noted in the case of a 1 10 volts interrupted direct current regulated to a current strength of 1 1 amperes by an ordinary resistance. In fact, in the latter case a much shorter spark will pass between the two wires leading to the resistance than would pass between two loose ends of wire, forming the terminals of the 110 volts circuit. A choke coil is available instead of a rheostat, or resistance, for regulating the strength of current for an .r-ray coil. and. in fact, the primary coil of an .r-ray outfit itself very often performs the function. In the author's 12-inch .r-ray coil the self-induction in the primary coil when the current (110 volts direct incandescent light current modified by a Wehnelt interrupter) has to pass through the two layers which form the whole length of the primary wire, is much greater than when the connections are made in such a way that the primary current passes through only one layer of the coil. There is quite a difference in the current strength which will be transmitted in the two cases with the rheostat turned to no resistance and only the flat end of the platinum rod exposed to contact with the electrolyte in the Wehnclt interrupter and with an .r-ray tube of the same degree of vacuum in the secondary circuit. "With great self-induction the primary current will be only 4 amperes, while the moment the connection is changed to a small amount of self-induction the current increases to .V, amperes. The increase in current is not due to the lessened ohmic resistance from paage through a shorter length of wire, for there is only about one ohm's resistance in the whole primary coil, and this forms an insig- nificant fraction of the total resistance in the primary circuit. The difference in current strength is due almost entirely to the difference in the amount of self-induction. \Yhen the interrupter is arranged to per- mit a much heavier current, the difference in self-induction is still more evident, and with the largest self-induction the primary coil acts really as a choke coil, and no matter how much of the platinum point may be exposed, not more than 10 or 12 amperes of current will pass through the primary coil. But with a small amount of self-induction a current of 1 .") or 20 or even 2"> amperes may be made to pass. The aut hor's S-inch .c-ray coil has a primary in which three different lengths of wire or num- may be used, and the variable self-induction obtained in iffers a valuable means of regulating the strength of the 'rent. In tact, with this apparatus, which is a portable one. of amperemeter is required. The different lengths of the iint exposed to contact with the liquid electrolyte, in the errupter. and the different amounts of self-induction in the dinu'. regulate the 110 volt- direct or alternating current to -t rengt h. Of collide, it was de-irable in t he beginning to have an amperemeter in t he circuit to mea-ure t he current st rengl h wit h all the various combination-, and a table \va> made out >ho\ving the results. DYNAMIC ELECTRICITY 139 A separate choke coil may be used to regulate the strength of current supplied to an .r-ray apparatus by introducing any desired impedence to the passage of the current. It is especially useful with the alter- nating electric-light current. And when it is separate, it effects a regulation of the current strength without producing variations in the inductive relations between the primary and the secondary coils. A separate choke coil may be used to regulate the current strength and take the place of a rheostat. When different layers of the primary coil, however, are used for a choke effect, we have, besides that effect, a change in the amount of induction in the secondary coil, due to the passage of the primary current through a greater or less number of turns of wire. The voltage of the secondary current depends more than anything else upon the ratio between the number of turns in the second- ary coil and the number in the primary coil. And if the latter number is increased, the voltage of the secondary current will usually be dimin- ished, and its volume or amperage will usually be increased. In connection with the subject of self-induction, it must be borne in mind that two currents of electricity do not flow through the same wire at the same time, either in the same or in opposite directions. Under any circumstances a current of electricity takes place in conse- quence of a difference of potential at the two ends of the wire, and. other things being equal, the current strength is determined by the difference in potential. The difference in potential is produced by the application of power derived from chemic action in the case of a voltaic battery or of a storage-cell, or from electric or magnetic induction and mechanic motion in the case of induction coils and dynamos. The difference in potential or voltage is an index of the strength of the electromotive force. In the case of a simple wire connecting the two poles of a voltaic battery in operation the electromotive force is a simple force exerted in only one direction and a current of corresponding strength will flow through the wire. But now if another voltaic batten- is connected in series with the first battery and the same simple wire, we shall have its electromotive force 1 also operative. If the two are exerted in the same direction, their effects will be added and the current strength will be determined by the sum of the voltage of the two batteries. If. on the other hand, the two batteries are so connected that they would tend individually to send a current through the conducting wire in opposite directions, then the resultant current will flow through the wire in the direction controlled bv the battery having the greater electromotive force, and the current strength will correspond to t he- difference' between the two opposing electromotive forces or voltages. The potentiometer for measuring the electromotive force of a voltaic cell or battery employs this principle. Self-induction may cause a counterelectromotive force tending to produce currents simultaneously with the initial currents, and opposed to them. An illust ration of this condit ion may be found in the case of a force- pump, like a fire-engine, sending water through a hose-pipe and actuated by a constant steam pressure. When the nozzle is at the same level as the pump, the rate of flow will be regulated by the resistance due to friction, and this will depend upon the caliber and length of the hose- pipe. But if the hose-pipe is carried up to the second or third ston of a house, a counterpressure is produced by the force of gravity, and the rate of flow will correspond to the difference between the pressure exerted bv the steam and that exerted bv gravitv. The frictiona! 140 MKDK AL ELECTRICITY AND ROXTGEN RAYS resistance in this illustration is analogous to ohmic resistance, or the electric resistance which can he measured in ohms and which depends upon the electric conductivity of the wire and its length and thickness. The counterpressure due to the force of gravity is analogous to the rounterelectroinotive force developed by self-induction. Self-induction may be used to render an intermittent current practically continuous. The break current or the electromotive force induced when the initial current ceases to flow is a powerful one. and is in the same direction as the initial current, and may bridge over the period between one pulsation of the initial current and the next. In such a case the make current or the electromotive force induced when the initial current again begins to flow is in the opposite direction. and reduces the flow of the initial current to some extent. The current How may. therefore, be practically continuous and of uniform strength. Such self-induction coils are in use in connection with a mercury arc rectifier as part of the apparatus employed for converting an alternating current into a direct current, suitable for charging storage-batteries. Self-induction Dependent upon the Nature of the Initial Cur- rent. There is practically no self-induction produced by the passage of a continuous current through a straight wire. But when the current is one of an alternating character, especially if of very high tension, the self-induction, even in a short straight wire, becomes so great as to offer an impedence as great as that of an air-space of one or more inches. Under most conditions, if the two terminals of a source of elec- tromotive force are connected with the ends of a short heavy copper wire, every bit of the current will pass through the wire, and even if its ends are bent around so as to be within an exceedingly small distance of each other, no spark will cross that space. But with the modern high-frequency current apparatus for therapeutic use the self-induction developed in the wire offers so great an impedence that the current will flash across a space sometimes as great as 4 inches, instead of passing through a foot or two of a heavy copper wire. This is in spite of the fact that the ohmic resistance of the copper wire may be so slight that it would tranmit a thousand times that amount of power in the form of a continuous current of either high or low voltage. The amount of reactance or counterelectromotive force due to self- induction is usuallv diminished by adding to the capacity of the circuit or bv the use of a condenser, and this is one reason for the necessity of a condenser in the Huhmkorff coil. The tot;d impedence in a circuit is usually made up of the ohmic resistance and the reactance or self-induction, and usually the square resistance and the reactance. Thus, if the ohmic resistance is '.] ohms and the reactance \ ohm.-, and the current an alternating one ot .")( I cvcles a second, and the voltage 1 20. the total impedence would be .") ohm- '_'">. the -i|i ia re of ."> !) Hi, the sum ot the squares ot '.] and 4 ). 'J he reactance would be increased bv the presence ot a sot t -iron core. Kven the two supply wires have an inductive effect upon each other which ha- to l.c taken into account m electric lighting and power systems. A- an example, an alternating current passing through two wire- ot % J~0.()U(i circular mils, and 1 inches apart to a ">0 horse-power t away, suffers a loss of (>.."> per cent, from inductive re- DYNAMIC ELECTRICITY 141 The unit of inductance is the henry, and equals the inductance of a circuit when the electromotive force induced in it equals 1 volt, when the exciting current varies at the rate of 1 ampere a second. And if a counterelectromotive force of 1 volt is set up in a circuit when the current is increased at the rate of 1 ampere per second, then the self- induction of the circuit is equal to 1 henry. The henry is the unit of induction in all eases, not merely in that of self-induction. The construction of coils to have a certain self-induction is largely experimental, and the details are different with each different com- bination of current and apparatus. The primary windings which produce the most desirable 1 amounts of self-induction in .r-ray coils are described with practical details in the chapter on .r-ray coils. The Oudin resonator furnishes a most striking example of self- induction. An alternating current of very high tension and high- frequency supplied by an induction coil and two Leyden jars passes through one or two or three or more turns of wires and beyond one of the 1 terminals the 1 wire 1 is continued in an ascending spiral for twenty or thirty turns. The bare binding posts by which the wire from the Leyden jars are 1 connected with the wire 1 of the Oudin resonator may be touched by the finger without receiving a disagreeable spark. But the effect is multiplied by each turn of wire 1 , and at the free end of the' resonator the wire gives off an electric effluve or visible brush discharge. 3 or 4 inches long, and if the finger is brought within 1 inch or so, a powerful stream of white sparks, mem 1 or less painful, will be received. The Interrupter. A continuous current or one 1 of uniform strength and passing in eme 1 direction doe's not induce a current in a neighboring wire. It is necessary that the current should be made 1 and broken at regular intervals and with greater or less rapidity. For most purposes the rate of interruption is from 1200 to 2000 times a minute 1 . The 1 form of apparatus employed varies according to the strength of the 1 current and the 1 rapidity required. Tin Electro magnetic Vibrating Interrupter or Hammer Interrupter. This is the form almost always employed in connection with faradic coils, and often with Kuhmkorff coils. It may be used with .r-ray coils, but some other type is usually selecte-el when heavy currents are to be employed. It consists of a disk of iron or stee 1 ! fastened upon a strip of spring metal, which te'nds to keep the hammer pressed lightly against a point of contact from which the 1 hammer is drawn away bv the attraction of an electromagnet. The 1 moment the contact is broken, the current ceases to flow through the winding of the electromagnet and the hammeT springs back to the point of contact again. Kach cycle consists in making the 1 current, attraction by the 1 electromagnet, breaking the 1 current, cessation of attrae'tion by the 1 electromagnet, and making the current again. \Yhen properly adjusted, such an interrupter begins to act the 1 moment the current is turner! on by closing a switch or by immersing the elements in a battery. If it does not start at once, it may be because the point is not in contact with the hammer or because the point is screwed so far forward that even the pull of the electromagnet will not separate the hammer from the 1 point of contact and break the current. This adjustment must be made to enable it to act properly, but even then the' interrupter will sometimes fail to start spontaneously, and will require a touch with the 1 finger to star; 142 MEDICAL ELECTRICITY AND RONTGKN KAYS it. This may properly bo regarded as a structural defect which should be remedied by the manufacturer. The points of contact on the hammer and on the surface opposed to it should be of some metal which does not easily oxidize, either from exposure to the air or under the action of an electric spark. The metal strip on which the hammer is fastened may be so made that even when the current is entirely disconnected from the apparatus it will vibrate back and forth for some time before coming to rest. In this case the rate of interruption will be determined to a great extent by the periodicity of the spring itself, just as the periodicity of the hair- spring of a watch keeps it vibrating in seconds exactly the same from the time that the watch is wound up until it runs down. In the case ot the watch, the force exerted by the mainspring varies tremendously during this time, but the periodicity of the hair-spring's vibrations continues the same. An interrupter generally has a periodicity of its own. which can be varied so as to produce rapid or slow interruptions in the primary current. This adjustment is sometimes made by turning a screw which advances the point of contact and makes the to-and-fro path of the hammer and its periodicity shorter. The Ribbon Interrupter. To secure a very great range of variation in periodicity the vibrating hammer is fastened to a steel band which is held tightly at its two ends, and the tension upon which can bo varied by turning a thumb-screw. Its rate of vibration can be changed from a rate so low as to give a coarse, rough, bass sound, by which the inter- ruptions can almost be counted, to a fine, almost inaudible sound, representing almost the highest note perceptible by the human ear. The secondary current, especially its physiologic effects, are greatly influenced by the rate and character of the interruptions in the primary cm-rent. Atonic or A /n riof/ic Interrupters. Gaiffo and other manufacturers nf ./--ray coils have fitted them with hammer interrupters in which the linger. This is accomplished by having the pressure of the spring strong enough to prevent a rebound when the hammer is pressed back against the point of contact from which it has been separated and allowed to fly back. Of course, the electromagnet must be strong enough to overcome the pressure of the spring and draw the hammer away from the point of contact. Such an interrupter is designed to be ifoverned by onlv two forces, the attraction of the electromagnet acting as long as the current flows through its winding and the pressure nl the spring. The latter is so adjusted that at no part of its path is oils rebound trom the point ot contact. The spring in to vibrate back and forth. The point of contact rward that the spring is never allowed to reach its neutral point : it is alwavs making pressure in the same direction, never in the opposite or rebound direction. This is thought to be more absolutely harmonious with the current and to give a better character of interruption for ./'-ray coils than those with an inherent periodicity. 1 1 n in an r infi rru pit i s may be act uated bv t he iron core of the primary coil itself, and the contact which 1 hev make and break may control the primarv current. Thi- is almost ahvavs the arrangement in faradic coils, and i< sometimes used in small .r-rav coils. Another arrangement DYNAMIC ELECTRICITY 143 the primary circuit by its mechanic to-and-fro motion; but it is at a distance from the primary coil, and its own motion is not due to the magnetization and demagnetization of the con; of the primary coil. A separate electromagnet actuated by a much weaker current sets this interrupter in motion, and it mechanically makes and breaks the heavy current for the primary coil just as if it were moved back and forth by any other force. The weaker current belonging to the interrupter and its electromagnet is easily and uniformly interrupted, and the uniform to-and-fro motion of the hammer is more assured than if it depended upon the complete interruption of as powerful a current as that of the primary of an .r-ray coil. The hammer goes back and forth, regularly touching and withdrawing from the point of contact where the primary current is made and broken; and this regular motion is independent of the primary current, and goes right on, even if an arc forms temporarily across the space and the primary current thereby fails to break for the time being. The Wheel Ti/pe of Electromagnetic Interrupter. This is shown in the appended diagram (Fig. 113). The contact is broken at c by Fig. 113. Wheel interrupter. the mechanic motion of the hammer, and this is produced by the pressure and relaxation of the eccentric, e. The latter is fastened to a revolving wheel whose four spokes are permanent magnets. When the contact is made at c, the current flows and the core of the primary coil becomes a powerful electromagnet, exerting an attraction for the magnet whose opposite pole is near it. and a repulsion for the magnet whose nearest end has the same polarity as that existing at that end of the iron core. These forces start the wheel in rotation, and the eccentric presses against the spring metal support of the hammer, breaking the contact at c. Momentum carries the wheel around to a position where the contact is again made and where the same magnetic forces again become operative, giving the wheel a fresh impetus in the same direction. It is a simplified type of electric motor, and produces a very rapid and uniform interruption of the current. The currents used for faradic coils are not strong enough to require such an elaborate interrupter, and it will not work well with the heaviest currents used for .r-ray work. It has proved useful, however, in apparatus for the production of high-frequency cm-rents. and one such interrupter is reported to give an excellent output of 144 MEDICAL ELECTRICITY AND HOXTCKN KAYS 100 to o()0 millianipcres. \vith a primary current of 1 ampere or con- siderably less. All the interrupters described above depend upon the alternate magnetization and demagnetization of an electromagnet, these caus- ing to-and-fro movements in the armature which mechanically make and break the current in the electromagnet and in the primary coil. These two are sometimes the same and sometimes separate coils of wire. Mi cl/iitn'r Interrupters. There are also interrupters which make and break the primary current by means of the motion of one of the points of contact, this motion being produced by a motor of some kind which acts quite independently of the current which it is designed to control. The arc which tends to form when the points of contact are separated would allow the current to continue to flow across that space. It is usually suppressed in these interrupters by having the points of contact below the surface of a liquid, such as alcohol. The contacts may be like those of the revolving commutator of a motor or dynamo, or the contact mav be between liquid metallic mercury and some solid metal. Mercury interrupters are of two types- - the mercury dip and mercury jet inter- rupters. All these except the Leduc interrupter are of use chiefly for high- frequency currents and the x-ray, and are described in the section upon the latter subject (p. 854). Leduc s Lnlcrniptcr. Our diagram (Fig. 114) shows Stcphan Leduc 's modifi- cation of the Contremoulin interrupter. It consists in making one of the brushes movable, and thus enables one to regu- late the fraction of the total period of the interrupter, during which the two brushes shall be in contact with the same pair of metal strips. This fraction can be varied from a very small fraction I,,, 1 ,,,,), up to the full time represented by the length of the metal strip. \o current can pass through the interrupter when either brush is in contact with the insula- ting substance or when the brushes are in contact with metal strips belonging to different pairs, and therefore having no metallic connection with ea< - h other. To produce a contact lasting only a very small trac- tion of a period the movable brush is placed in such a position that the one metal strip only begin.- to touch it as the opposite strip is just leaving the other brush. To produce a cont act last ing tor the max in mm time the brushes are placed directly opposite each other, and in this position "tie brush i- in contact with a certain metal strip the entire time that the other bm-h is in contact with the connected metal strip. Intermediate positions of the movable brush allow the current to pass during a larg'T or -mailer fraction of each period. Knowing the fraction "f each period that the current is flowing and the tension ot the current as shown \>v a voltmeter in shunt, we can calculate the ia-sing through the patient or the apparatus, lie galvanometer, which is called a dead-beat e circuit will show the ouantitv of electricity Insulation DYNAMIC ELECTRICITY I4o passing, this being indicated in milliamperes and being actually the average rate of flow of the current, including the portions of time when the current is interrupted. If the rate of revolution is rapid, tin- periods occupy a shorter length of time, but there are more of them in a minute and the current strength remains the same. Very great variations in the rapidity of the interruptions produce changes in the physiologic effects, even though they do not change the average current strength. In regulating the fraction of each period occupied by the duration of the contact we may depend upon the graduated scale marked upon the apparatus. But if this is defective or is absent, the adjustment becomes a matter of calculation. In order to have a contact T ' of each period, close the circuit with a non-polarized resistance and raise the tension by adjusting the volt controller, for instance, until the milliamperemeter shows, for example, 10 milliamperes. Start the interrupter arid shift the movable brush to such a position that the milliamperemeter shows that a current of I milliarnpere is passing. Really this means that a current of 10 milliamperes is passing for T ^ of the time, and conse- quently Y'^ of each period. The proper position of the movable handle for other fractional currents is found in a similar manner. Stephan Ledtic has estimated the time during which the current passes even to so small a fraction as ^6000 ^ a seconc l f time. Liquid or Electrolytic Interrupters. These are used chiefly in x-ray and high-frequency work, and are described on p. 852. The Secondary Coil. This is a coil containing a very large number of turns of very fine wire which is very carefully insulated. The wire itself in an x-ray coil is No. 36; looks as fine as a hair; is wrapped with silk; and is coated with melted paraffin after being wound in the sec- ondary coil. The secondary coil in a 12-inch x-ray coil contains 40 miles of wire. The secondary, coil in a faradic battery contains from 1000 to 8000 feet, the larger number of feet corresponding to the faradic coil with fine wire, the 1000 feet corresponding to the faradic coil with coarse wire in the works of some authors. In a great Rnhmkorff coil, made by Apps for Spottiswood, there were 280 miles of wire. It gave a 42-inch spark through the air when actuated by a voltaic battery of 30 Grove cells. Since the discovery of the .r-ray, coils of this power have frequently been made. Every time the cm-rent is made or begins to flow in the primary coil a current is induced in the secondary coil. This is momentary, and flows in a contrary direction to that of the current in the primary coil. When the primary current is broken or ceases to flow, a current is induced in the secondary coil which is momentary, and in the same direction as the current which has just ceased to flow in the primary coil. The break current is direct and produces a more powerful dis- charge across an air-space or through a vacuum tube than does the make current. The latter is what is spoken of as the inverse discharge in .r-ray work. There is thus a distinct polarity to the secondary current. Although it flows first in one direction and then in the other the greatest effect is produced during the periods when a certain pole of the coil is the positive. Tin's can be seen in .r-ray or in any other vacuum tube work, and a difference can even be seen in the sparks pass- ing across from one pole of the secondary roil to the other. The negative end of the spark is much brighter and of a violet-white color, while the 14t> MEDICAL ELECTRICITY AND ROXTGKX KAYS positive end is not so brilliant and has a more reddish tinge. And then, again, the successive sparks, each of which can be seen as a complete more or less zig-zag line, are more divergent at the positive than at the negative pole. A photograph made of a series of sparks passing between the two similar blunt metal terminals of a 12-inch x-ray coil shows that the majority of the sparks start from the same spot on the positive ter- minal and pursue the same path for a certain distance, then separate, to converge again on approaching the negative pole, but no two paths coalesce, and they all reach different parts of the surface of the nega- tive terminal. The result is entirely different, however, when one elec- trode is conical and the other is a flat metal plate (Fig. 115). What has been said, however, is not intended as a statement that the spark originates at one pole and terminates in the other pole. It is probable that the discharge takes place simultaneously from both terminals. By the negative pole of the secondary coil is meant the one which is the negative pole during the break or direct discharge. This is the pole which is always connected with the cathode or negative electrode of an .r-ray tube, and an important part of .r-ray technic is the sup- pression of the inverse discharge. In another part of the book (p. 709) will be found a description of the means adopted to prevent the inverse discharge from passing through the .r-ray tube in sufficient amount to be a disturbing factor. The only useful current supplied to an .r-ray tube is the direct discharge which is produced in the secondary coil by the break of the primary current. The inverse discharge which occurs alternately with the direct discharge is produced by the make of the primary current. During the inverse discharge the polarity of the secondary coil is just opposite to what it was during the direct dis- charge, and the current may be said to pass through the .r-ray tube in ing direction. I'nder normal conditions the .r-ray tube appears into a brilliantly fluorescent half in front of the plane of the disk or ant icathode, and a dark hemisphere behind that When there is a {iood deal of inverse discharge, but still con- siderable direct discharge, the whole tube appears lighted by a streaky or irregular greenish fluorescence. There is sometimes a great deal of inverse discharge and -carcely any direct discharge. This condition i- indicated by the absence of the illuminated hemisphere in front ot the plane of the ant icat hode in place of which there is a dark hemisphere with only one bright given >pot where the cathode ray. starting from (very spot on the platinum surface, strikes the glass wall of the tube and (generates .r-ravs. The half of t he tube which should be dark is irreg- DYNAMIC KLECTR1CITY 147 i ularly fluorescent from similar cathode rays originating from other parts of the antieathode or from the accessory anode. The tube in such a condition looks like a tube connected with the wrong poles of the coil. We cannot secure any useful .r-ray from a tube of the usual model during the make or inverse discharge of the coil. The best that can be done is to prevent any considerable part of this inverse discharge; from passing through the tube, and thus to secure the greatest efficiency during the alternate periods when the direct discharge is passing through the tube. The importance of the subject lies in the fact that any conditions which permit the passage of the inverse discharge through the tube obstruct to about the same extent the passage of the direct discharge and reduce the output of the tube. In the extreme case mentioned a few lines back, and which the author can duplicate experi- mentally at any time, no effective .r-ray at all is produced. The wear and tear upon the tube are excessive. The icirc in the secondary coil is almost as fine as a hair, and the object of this is to bring every turn of it as close as possible to the primary coil, so as to cut as many of the expanding and contracting lines of force as possible. It is not sufficient that the secondary coil should be outside of the primary coil, it must also be very close to it. The secondary winding for one of the smaller induction coils for faradic treatment is not a difficult matter. The difference in potential between one end of the long secondary wire and the other is not sufficient to produce a spark of any appreciable length, and so the ordinary methods of insulation arc sufficient. The insulated wire is wound upon a reel, just as thread is wound upon a spool, one layer after another, all con- tinuous and all in the same direction. The insulated beginning arid end of the wire are both left outside,' where they can be connected with the binding posts, to which may be attached the conducting cords leading to the patient. These binding posts arc of metal, and are fastened upon an insulated base of varnished wood, hard rubber, ivory, indurated fiber, marble, or slate. The regulation of the strength of the cur- rent passing to the patient is sometimes secured by changing the primary current, by changing the resistance, or by changing the number of cells if a voltaic battery is used. It is much better, however, to have the primary and secondary coils so mounted that their relative 1 position may be varied. The strongest secondary current is produced when the secondary coil entirely covers the primary coil, and as the primary coil is drawn out from the lumen of the secondary coil, the secondary current becomes gradually weaker. Measuring the distance in cen- timeters that the movable 1 coil is displaced enables one to use a mathe- matic number in recording the strength of the current applied to the patient. The quality of the secondary current varies according to the number of feet of wire in the secondary coil and the rapidity of the inter- ruptions, and it will be seen (p. 4(>7) that very different physiologic and therapeutic effects may be obtained by means of such variations. The Knft-iroii core has always been considered an important part ot an induction coil. Its effect is to increase the strength of the secondary current by adding its own expanding and contracting lines ot force to those 1 of the primary coil. It is best made of soft-iron wires in a straight parallel bundle'. These acquire and lose their magnetism when the primary current is made and broken much more 1 promptly and com- 148 MEDICAL ELECTRICITY AND HONTGEN KAYS pletely than a solid bar of the same weight. The strength of the sec- ondary current is very considerably augmented. As already stated p. 134), the core is not a necessity, and recent observations indicate that for faradic treatments the current has a pleasanter quality if there is no core 1 . The Condenser. This is not required with a liquid interrupter of the C'aldwell-Simon or \\ clinch types, but is required with many of the vibrating or other mechanic interrupters. It is made for an induction coil, of a great many layers of tin foil separated by mica or paper, and is usually concealed in the wooden base of the coil. The sheets of tin-foil are in two separate sets, and fit together like the two halves of a pack of cards when one half is held in each hand and the cards are being shuffled by pressing them together in an interlocking fashion. All the sheets of one half are fastened together by one metal clamp, and they really form a single large metal coating or armature of a condenser in which the other armature is formed by the other sheets of tin-foil, and the glass jar or plate is represented by the many sheets of mica or paper which prevent any contact between the sheets of tin-foil in one set with those in the other set. The condenser is designed to prevent excessive sparking at the interrupter, and in this way to produce a sharper and better break of the primary current than would be possible if the primary current continued to flow as an arc across the space after the contact was broken. The condenser takes up or absorbs the extra current, which results from self-induction in the primary coil at the moment that the circuit is broken. We have already seen (p. 135) that this extra current is of high tension, will spark across a considerable air gap, and has in this way some of the properties of static electricity. It very naturally'occurs that when the two armatures of the condenser are connected with the ends of the wire forming the primary coil in which such a cm-rent is generated, the condenser becomes charged. The effect at that moment is the same as when the inner armature of a Leyden jar is brought in contact with one prime con- ductor of a static machine, while the outer coating touches the other prime conductor. In the case of the induction coil the charge received by the condenser produces J ust Sl) much less tendency to sparking at the interrupter. The high electromotive force generated at the time of the bre;ik of the circuit ceases, and the condenser becomes discharged a> its outer ;md inner coats are connected bv the primary wire. It is then readv to perform its function at the next break in the primary current, i See also pages 242, 243.) I.iouid or ''electrolytic" interrupters do not require any condenser to suppress the spark when the current is broken. 'I here is a tremen- doiis difference between the conduct ivit V through a complete liquid path and the resistance offered by the mass <>] incandescent vapor which H irenerated at the narrowest part of the liquid path. '1 his results in a practically complete obstruction to the flow of even the high-voltage extra current occurring from .-elf-induction in the t irima rv circuit at i he t ime it is broken. The general arrangement of an induction coil fed by a. voltaic battery i- shown in Fr_ r . 1 1. // i- the voltaic battery. I 1 ' mm one pole 1 1 battery a wire leads i lirect ly to />. where it is c< >nt in nous with the prin ;trv cnil of wire. The other end of the orimarv wire is shown in DYNAMIC ELECTRICITY 149 h H the diagram at the opposite end of the coil, but in actual practice both ends of the primary wire are usually brought to the same end of the coil. The other end of the primary wire leads to the base of the vibra- ting hummer, //, which, when no current is being used, is pressed lightly against the contact /> by the springiness of its metal stem. From /; a wire leads to the other pole of the battery when the switch, til, is closed. Wires lead from the two ends of the primary wire to the two armatures of the condenser, c. When the current is turned on by changing the switch from dm to dl, the current passes through k to h, and through the stem of /;, and a connecting wire to one end of the primary, through the primary wire, and thence to the other pole of the battery. The soft-iron core / becomes a powerful electromagnet and attracts the hammer h away from the contact k and breaks the current. This break is accompanied by the induction of a high-tension extra current in the primary which surges out through the conducting wires, most of it going to the condenser where such large electric capacity is provided. Set screws not shown in the diagram regu- late the pressure of the ham- mer upon the contact while at rest, and also the distance that it can go when drawn away from it. In no case is it neces- sary for it to touch the iron core. Motion toward the mag- net i/ed iron core is in a direction to break the current, and no electric contact is required to be made at that end of its path. The secondary coil has its two terminals leading out and connected with binding posts. The smaller induction coils are called faradic coils, and conduct ing cords lead from the two terminals to electrodes, which are applied to two different parts of the patient. In the case of the very large Ruhmkorff coils, suitable for .r-rav work, a spark or an actual flame may pass across between the two terminals, when a full current is turned on, unless the two terminals are connected with an .r-ray tube oi 1 some other apparatus through which the secondary discharge is conducted. This is because of t he enormously high voltage or difference in potential between the electric charges nt the two ends of the forty miles of wire forming the secondary coil. The charge is developed thousands of times a minute: its duration is only momentary, but during its continuance there is an almost irresistible tendency for the two opposite forms of electricity, posit ive and negat ive. to rush toget her and become neutralized. The tension at the two poles or terminals i- so great that a succession of sparks will pass across the 12 inches of air-space which separate them, although every inch requires a voltage variously estimated at from 10. 000 to .'JO.OOO. If not quite enough current is turned on to produce a spark across that distance between the poles, a brush discharge of violet light, accompanied by a crackling sound, will take place into the air surrounding the two I Iffllft Fiji. 116. (irnrral arrangement turn coil fed hv a voltaic of an induo- battery. Lo(J MKDH'AL KLK( TRICITY AX!) RONTGEN RAYS poll's. Ill cither case a spark will fly to the finder or any other conductor brought near cither of the poles, and the same is true even when the discharge is passing through some apparatus to which both poles arc connected. This property possessed by high-tension electricity of sparking across an air-space or through any other insulating substance to a neighboring conductor has to be constantly borne in mind in the therapeutic and also in the industrial application of electricity. It is the cause ot most of the accidents occurring to human beings in power- houses and elsewhere, and is often the cause of explosions and fires occurring in connection with the use of electricity for light and power. It must be guarded against in the construction and manipulation of eleetrothcrapeutie apparatus, to prevent puncturing .r-rav tubes and burning out induction coils. Fortunately, there is nothing dangerous about the sparks or shocks which may occur from handling electro- therapeutic apparatus. At the same time they are disagreeable, and should be prevented by care in manipulation. The difference in potential between any two parts of tin. 1 secondary wire varies according to their relative position in the scries of turns that make up the coil. Imagining it for the purpose of explanation as a single spiral layer of wire wrapped around a very large glass cylinder, the difference in potential between the wire at the two ends might be !")(). 000 volts, or sufficient to spark across an air-space of 15 inches. The difference in potential between any two consecutive turns, on the contrary, .would be very small. Roughly speaking, it would be the total voltage of the coil divided by the number of turns. In the same way the difference in potential between any part of the wire is equal to the same fraction of the total voltage that the number of turns of wire between these two parts forms of the total number of turns. If the two ends of the wire are bent around, so as to be brought within 12 inches of each other, a spark will pass between them even through the air. Bui it is quite different with two consecutive turns of wire, between which the difference in potential may be so slight that an ordinary silk wrapping will prevent any passage of electricity from one to the other, even if they are wrapped one on to]) of the other. The difference in relative position has reference to the distance between them following the continuous wire from end to end. It has no refer- ence to the physical position of the turns. They might be wound in such a way in making the coil that two turns lying in physical contact with each other might be portions of wire many thousands of turns apart if the wire were followed. The difference in potential between the extreme ends of the secondary wire is so great that the terminals cannot both be placed at the same end of the coil. If they were, there would be sparking across from one to the other and also from the poles to intervening turns of wire, and one of the latter sparks would ruin the coil bv destroying the insulation of the wire at that place in the coil. For the same reason the secondary coil cannot be wound in successive layers, each continuous from one end of the reel to the other, like a -pool of thread. With such an arrangement portions of 1 he wire many thousands of turns apart would be placed in such close physical prox- imity that a disruptive discharge would pass from one such turn to am it her and rum the coil. DYNAMIC ELECTRICITY 151 The form of winding which has been adopted for rr-ray coils consists in having the wire in several flat spirals, separated from each other by disks of hard rubber. Each flat spiral contains consecutive turns, and between the beginning and end of that section there is not enough difference in potential to break through the insulation of silk and wax and cause a short circuit. The additional insulation afforded by the hard-rubber disk is sufficient to prevent a discharge occurring between one section and the next adjacent one, in spite of the considerable difference in potential. Sections near the ends of the coil have an. enor- mous difference in potential, but a discharge is prevented from occur- ring, first, by the physical distance between them; second, by the insulating properties of the mass of wax in which the whole coil has been boiled and is embedded, and, third, by the insulation of the numerous hard-rubber disks. The whole coil is in the 1 form of a hollow cylinder built up over a tube of micanite, a compound of mica and shellac, which forms the best possible 1 insulator. This shemld be 1 long and thick enough to prevent a discharge passing from one enel of the secondary coil to the primary e-oil, and through that to the other end of the see-emdary coil. The 1 resistance in the primary coil is very small, and its position inside the secondary coil ami extending from one' enel of it te> the either wemlel make it offer a short e-ircuit for the secondary discharge if the primary coil were 1 insufficiently insulated. The com- ])le i te i d .r-ray coil consists e>f a secomlary coil and a primary coil which has no connection with the secondary coil, but lie's loeisely in the micanite 1 tube lining the secomlary cenl. The primary coil may be pushed in Fi semie 1 intermediate part of the secondary coil from the discharging rods often connected with its two pole's. Sue-h a spark would ruin the coil. in building a coil up in disks, like sections of wire wound between hard-rubber disks, it is necessary that the- wire in each see-tion shall be continuous with that in the 1 adjae-ent sections, and that the 1 elirection of the cunvnt shall be the same 1 in all the seM-tions. For instance 1 , looking at the end of the coil, if the 1 cunvnt in the first section pusses in the 1 dirertion of the 1 hands of a wate-h at a e'ertain period, then the 1 cunvnt in all the other sections must pass in the 1 direction of the 1 hands ot a wate'h at the 1 same 1 period of time 1 . The 1 connection between the 1 first section and the 1 see-emd may be 1 made 1 by passing the e'entral e-nd of the first spiral wire through a hole 1 in the hard-rubber partition near the central (Mid of the adjacent spiral wire. When it conies to joining the 1 Io2 MEDICAL ELECTRICITY AND RONTGEN RAYS other or outer end of the second spiral, it is passed through the outer part of the next hard-rubber partition and soldered to the outer end of the next spiral. So the different sections which have been wound separately are united into a single continuous wire, but then 1 is a very necessary precaution to be taken in securing the proper direction of the current in each of them. If they are all strung along on the axis of the coil, so that they are all, for example, right-handed spirals, as in Fig. 118, .1 and />', the current in each section would be Mowing in an opposite direction from that of the adjacent sections. The reason is very simple: if the current in one is flowing from the outer end of the spiral wire to its inner end, it is continued in the next section from the inner to the outer end of the spiral wire: and if they are all light- handed spirals, the current in one is in an opposite direction to that in the next spiral. The current in each section is not merely flowing through the wire, but is actually excited in that section; and in the bad arrangement shown in Fig. 118, it would completely neutralize and arrest the current excited in the opposite direction in the adjacent sect ion. Fig. 119 shows the proper arrangement of the various sections. There are right-handed and left-handed spirals alternately, and the current flows in the same direction in all. The picture is purely dia- grammatic. Kach spiral really is a disk-like mass containing thousands of feet of wire, and its flat surface is separated from that of the adjacent section by only the thickness of a hard-rubber disk. The arrows show the direction of the current at the time when the terminal near .1 is the negative and that near (' the positive pole of the secondary coil. The arrows would all have to be reversed to show the direction of the current during the period when .1 is t he positive and (' the negative pole. In the last lew paragraphs we have spoken ol tin- direction ot the cur- rent, and n might have been called the direction of the electromotive force. The make or, especially, t he break of t he primary current induces an electromotive force m every individual turn in every section ot the secondary (i oil; and if the latter is correctly constructed, all these electromotive forces are added together in -cries and the rcM.lt in voltage i- perfectly enormous, just as it would be il a tremendous num- ber of voltaic cells were set up in series. The current which will >park across between the terminals or which will pass through a vacuum tube i if ot her appa rai us connected with the two poles is ot great voltage and of very -mall amperaife. The power possessed by the discharge from the secondary coil is expressed in watts, one watt being equal to 1 ampejv of current at ! volt of potential. The total number of watts equal- the number of amperes multiplied by the number of volts, and DYNAMIC ELECTRICITY IO.5 no more power can come out of an induction coil than was put into it. The intake, in a typical case, may be 20 amperes at 100 volts, making 2000 watts, and the result ing secondary current may have a voltage of C>0, 000. Supposing all the power of the 2 kilowatts in the primary current were converted into power as the secondary current, then we might have the following equation: (H),000, the number of volts in the secondary current, multiplied by the number of amperes in the secondary current, equals 2000, the number of watts, 60, 000 (x amperes) = 2000; x = (io'ooo ; x = jJ5 amperes; x = 33 milliamperes. These 33 rnilli- amperes would be found to be the intensity of the secondary current, ex- cept for the fact that the primary and secondary currents are interrupted, and that the secondary current is of an alternating character with wide 1 variations in intensity. The number of watts as a maximum must be re- duced materially, because the induction coil wastes some of the power put into it. There are certain lines of force 1 leaving the two ends of the iron con 1 and arching over from one end to the other which are not cut by the secondary turns of wire. This is true of any aeroferric type of magnet. It will be seen on another page 1 that this loss of power is prevented in transformers of the closed magnetic ring or complete 1 ferric- type. There 1 is some loss of power e>r reduction in the number of watts yieleleel by an induction e'oil on account of the 1 ohmic resistance of 200,000 feet of fine 1 wire 1 . This loss woulel be 1 evident as overheating of the 1 secondary coil, except for the fact that the 1 ohmic or frictional resistance is in proportion to the 1 intensity or amperage 1 of the current, and not at all to the 1 pressure or voltage. A certain number of watts of electric power in the 1 form of a current of 60, 000 volts and 33 milliamperes will pass through a line 1 wire without perceptible heating, whereas the 1 same 2000 watts of power as a current of 10 volts and 200 amperes would heat the 1 wire white 1 hot and }>erhaps vaporize 1 it. The ohmic resistance in the 1 secondary coil is great enough, however, to make a material dif- ference between the number of watts applied to and the number yielded by an ineluction coil. But this output or secondary current has wide variations in intensity at different parts of each of its 2000 to 10,000 cye-les a minute. At a certain instant then 1 may be a powerful current in eine 1 direction: at another instant no current may flow, and at another instant 1 he-re- may be 1 a powerful current in the 1 opposite 1 direction. A milliamperemeter in which each unit indie-ates a milliampere (joVc ampere-) may be 1 useel to measure the 1 stivngth of the 1 secondary current. It may be 1 connected with one pole of the e-oil and with the 1 .r-ray tube and register in this way the 1 intensity or ampe'rage of the 1 current pass- ing tlmmgh the tube-. This will appear to be from or even a minus quantity up 1o 2, 4. (>, X, or even 15 to 30 niilliamperes. The 1 milli- anipeTe-inele-r may be of the D'Arsonval type, and depend upon the 1 directional effect of a current passing through a coil which is in close 1 relation with a powerful magnet. In such a case 1 the neeellc 1 upon the 1 dial indicates in a geneTal way the average strength and direction of the 1 secondary current. The 1 alteTiial ions from the dhvct to the 1 inverse- discharge are so rapid that they are 1 not shown by such an instrument. Such a ine-te 1 !' may indicate when the .r-ray tube 1 is giving a radiance by which a moderately gooel picture 1 may be 1 made 1 , and this would indicate 1 that the inverse 1 discharge 1 was ee[iial to the eliivct. The value of this type 1 of milliamperemeter as a guide 1 to the 1 propeT application it the .r-ray is consiele'ivel at another place (p. 859 >. 154 MKDICAL ELECTRICITY AND RONTGEX RAYS A hot u't'ir mi II (amperemeter between one 1 pole of the coil and the x-ray tube gives a reading of several niilliamperes, and is not influenced by the amount of inverse discharge. because that has the same heating effect as if it were in the right direction. In an experiment by the author a large hot wire milliainperemeter intended to measure high- frequency and high-tension currents up to 650 niilliamperes intensity was connected with one pole of a 12-inch .r-ray coil. A wire fastened to the other binding-post of the milliamperemeter reached to within a few inches of the other pole of the coil. The 110 volts direct current of the incandescent electric lighting system, afte-r passing through a \Yehnelt interrupter, produced a current of 6 amperes in the primary coil. A regular ilame passed across the 4 inches separating one pole of the coil from the wire leading to the milliamperemeter. The length of the spark showed a voltage of 40,000 and the milliamperemeter in- dicated an intensity of 150 niilliamperes. Here there was an apparent power of (iOOO watts produced by the application of about GOO watts, a considerable part of which was certainly expended in overcoming the resistance in the 'liquid interrupter. The apparent discrepancy is due to the fact that the voltage is greatly reduced during the passage of the continuous flame, just as 100 volts will maintain an electric arc 1 inch long which it would take 10,000 volts to originate. Spottiswood's Induction Coil. This was a great coil made in ls~6. and some of the facts in regard to it will be of interest. It was 4s inches long and 20 inches in diameter. The primary coil was of copper wire. -^ inch in diameter and 2000 feet long. It made 1334 turns in six layers. The secondary coil contained 240 miles of wire in four different sections: 2 of wire T /,-- inch in diameter, and two of a little larger wire: the total number of turns being H42.000. A battery of 5 galvanic cells produced a 2S-inch spark; 10 cells gave a 36-inch spark, and HO cells a spark 40 inches long. IRON" CORKS Outside DianiPtPr I-piiRth. Weight, of Ciirp. Inches. Inches. Pounds. :i..")(i 4 \ ti7 :-!.si 41 1)2 PRIMARY COILS H. W. (',. I. riiirth, Resistance, Weight. Conductivity, Yard-. Ohms. Pounds. Per Cent. i:; tn in _>.:; .">."> '.:; i:; :()! 0.211 si SI'.COXDARY Coll. I. (-Mirth, Miles. DYNAMIC KLKCTKK'ITY !.")"> CONDENSER 12(> sheets tin-foil, IS inchesX'S', inches, separated by two thicknesses of varni.-hed jiaper, .011 thick, 111 inches XH indies surface. BATTERY ."> one-(iuart drove cells, plates t>| inches / ','> inches, <*ave 2S-inch spark with smaller primary. 10 one-([uart drove cells, plate.- (>[ inches X '> inches, <:ave o.Vinch spark with .-mailer primary. :>() one-quart drove cells, plates (>} inches X -'i inches, ;ave 42-inch spark with smaller primary. The secondary discharge is seen, from the above examples, to con- sist of a succession of waves in alternate directions, of extremely high voltage and of an amperage much greater than is produced by a static machine and much greater than could be maintained by the same power as a continuous current of the same voltage. The Undulatory Nature of the Induced Current. A tracing made by means of Duddell's oscillograph shows that the current from an induction coil usually consists of a series of separate curves, (Mich beginning suddenlv at a distance from the neutral line and descending \ \ \ \ \ \ Fif:. 120. Secondary currents from induction coil with iron core. or ascending more or less gradually toward it. Fig. 120 shows the kind of a curve made by the secondary current of an induction coil with a short secondary winding and a soft-iron core. The break currents are seen below the neutral line and the make currents above it. In the case illustrated the make currents are not so powerful, but last much longer than the break currents. The latter are of short duration and of abrupt character. According to the observations of Lewis Jones, 1 such a current produces a much more disagreeable effect in causing muscular V V V V V V ~r. ~?~ ~r ~ r . ~T idg. 121. Secondary currents from coil without iron core. contraction than one illustrated in Fig. 121 produced by the same coil after withdrawing the soft-iron core. Kven this, according to Lewis Jones, is not ideal; there is too great a difference between the make and break currents, and a still greater uniformity would be better tor diagnostic purposes. This uniformity can hardly be obtained troni an induction coil, but is produced by the right character of inter- ruptions in a continuous current and in a circuit with little self-induc- tion. He uses this current, which is considered on another page 4 ( ,)2i under the name of the interrupted voltaic current instead of the faradic current, for diagnosis and treatment. 'British Medical Journal. October s, I'.HH. 150 MEDICAL ELECTRICITY AND RONTGEN RAYS Before leaving the subject it will he best to reproduce two more of Lewis .Jones' graphic representations. Fiji. 122 shows the character of an interrupted and reversed voltaic current in a circuit with little -elf-induction. For a certain period of time, the most favorable being j ,/,,,, of a second, the current strength is uniform and in the same direc- tion. Then a change occurs almost instantaneously and a similar period follows with the current in the opposite direction. With a proper Fii:. !_'_'. Lcduc currents. Interrupted and reversed voltaic currents in a circuit with little inductance. ; ntriTUpter the frequency of these cycles and the duration of the suc- cessive currents may be measured and regulated. The influence of self-induction in -uch a circuit is shown in Fig. 12o. where a few hundred turns of wire are introduced in the circuit. The result is that the current strength gradually increases from zero until its increase is cut short by the break and reversal of the current. The same sort of a curve in the opposite direction represents the current during the alternate period. There is scarcely a demonstrable interval b< 'tween the two periods <>f current flow. This form of current als could lie used as a substitute for the faradic current from an induc- Fit:. 124 sho\vs the primary and secondary currents in an induction a long secondary wire and without an iron core. 1 he upper line shows the primary current with its abrupt rise when the contact i_'!. ('urn lit.- in an induction coil with a lone Fccondarv \\irc and no inn is made, its continuance at a certain strength up to the instant that the current i- broken, and its sudden fall at thai lime. The lower diagram shows th' 1 secondary current: the curved lines, the make currents above and tin- break currents below the heavy neutral line. The differences between the two different currents in the secondary coil are important. They are in opposite directions. Thev attain DYNAMIC ELECTRICITY 1 ")" a maximum almost instantly when the primary current is made or broken, and very soon cease. The make current is not so strong a.-s the break current, but lasts longer and dies out somewhat more grad- ually than the break current. In this particular experiment the make current of the secondary coil lasted - r( ' J(T of a second, and the break current s -J--jj- of a second, the frequency of the interruptions in the primary current \vas SO times a second. It is necessary to have a separate electromagnet if a hammer inter- rupter is used with an induction coil which possesses no iron core. The ribbon vibrators as used in faradic coils, and usually actuated by the magnetized iron core, are equally desirable for separate use in this case. It is noteworthy, however, that no vibrating interrupter is perfect. The\" all fail occasionally to make a perfect electric contact, and this may occur at irregular intervals and produce a disagreeable effect upon the patient. The duration of flow of each secondary current should be about Yiv'ffo f a second to produce the best effect in exciting muscular con- tractions. Fig. 125 shows the primary and secondary currents in the same coil with a long secondary winding, but with a soft-iron core introduced into the primary coil. The primary current shows the effect of the I-'itr. 12"). Currents in an induction coil with a long secondary wire and an iron core: P, Primary; .S, secondary. additional self-induction. There is a choke effect when the current is made, and as this induced countereleetromotive force' in the primary coil disappears, the primary current gets stronger and stronger right up to the time that the contact is broken. The effect of this upon, the secondary current, which is the current applied to the patient, is shown to be very marked. The make current attains its maximum less sud- denly and dies out very gradually, lasting right up to the breaking ot the contact. The break current is a great deal stronger than without an iron core, and is of about twice as long duration. This is quite characteristic of the current from a faradic coil, and according to several observers it occasions more discomfort in the production ot muscular contraction in diagnosis or treatment than does the current from the coil without a core, or than a simple low-tension current interrupted rapidlv with or without alternation-. Besides being more or less uncomfortable, it is very difficult to make any accurate measure- ment ot the current passing through the patient. Tracings like those in the preceding paragraphs are to be made only with the most elaborate apparatus and preparation. Practically, one is limited in usimr an ordinary faradic coil to depend upon the sound of the interrupter for an indication of the rate at which the successive currents occur, and upon the length f the secondary coil and its distance from the primary c<'il to indicate the .-treiunh of the secondary currents. Xo measure- MEDICAL ELECTRICITY AND RONTCKN RAYS ment and no adjustment arc practicable 1 at the time of the treatment of the strength of each impulse of the secondary curient. and of its dura- tion as compared with the pauses between the make and break currents: in other words, of its actual duration and the fraction of each period occupied by it. The hammer or vibrating interrupter is another source of imper- fection in the ordinary faradic coil: a tracing of the currents will show that many of the contacts are ineffectual, and that there is a corre- e employed for the primary current, such as one which the present author calls the commutator type of interrupter. The Leduc interrupter (p. 144) is an example, and this will correct the irregularity in the current: but it yields such a desirable interrupted voltaic current that the induction coil would not be required at all. The effect of the iron core may be minimized by slipping a metal tube over it. This cuts the expanding and contracting lines of force as the core becomes magnetized and demagnetized, and whatever energy is consumed in producing electric currents in the metal tube loses its direct effect upon the secondary current. l_'ii. F:ir:tilic coiN: A. Ordinary arrangement. H. 1 lelmholt x's arrangement. VS fiirner or Neet's hammer interrupter fur Bois-Revinond slide furadic coil, t\\o ditter- iit arrangements: >'/. Standard: >', Ilelmholtz column: Km. electromagnet; P. pnmar\ and .Stv-. upper and lower contact screws; Sp, .-pring; Aux. arc., Helmholtz's Faradic Coil. This is an arrangement by means of which the secondary currents in each direction are made approximately equal. In the ordinary arrangement the make current is weak, impaired bv the self-induction in the primary coil, which causes the primary make current to increase less abruptly than it otherwise would, and hence to be less effective in inducing a secondary current. And in the ordinary arrangement the self-induced extra current in the primary cil ;it the brc;ik is immediately stopped by the fact that the circuit is "pen. It may produce a spark at the interrupter, but it has little effect upon the primary current, which ceases quite abruptly and produces a strong "break" current in the secondary. These conditions are shown in the diagram I-'iir. !'T. The heavy line shows the actual (nurse of . ry current as modified bv the influence of the extra current almost exdu-ivelv at the make. Kxcept for the latter the primary current would have followed the rectangular path marked " de-ii lerat u n i " at the ma ke. The ordinary arrangement of the vibrating interrupter of a faradic DYNAMIC ELECTRICITY 159 coil is shown in Fig. 126, A. Starting from the zinc polo of the voltaic coll, the. current finds only a single path through the standard St, the spring Sp, the contact screw $cr l , the primary coil p, the electromagnet //? (the primary coil and the electromagnet may he the same or may be separate and in series), and back to the other pole of the voltaic cell. When the current is made by contact with the screw Her 1 , there is but a single conducting path, as above described, and when the contact at primary uinse of the cur ^Secondary break current" Fig. 127. Faradic currents with ordinary Wagner hammer interrupter. that point is broken by the attraction of the electromagnet for the hammer, the current is completely cut, off. In Fig. 126, B, it will be seen, on the contrary, that at this stage the primary coil is short-circuited, and this permits of the full establishment of the break extra current in the primary. At this stage the primary coil is disconnected from the zinc pole of the battery. The extra current circulates in a complete circuit, consisting of the primary coil, the electromagnet, the Helmholtz column and the wire leading to it, primary Secondary make currenr break current Fig. 112S. With Ilehnholtz's arrangement. the spring of the interrupter and the auxiliary circuit through the contact screw .Scr 1 to the primarv coil. Through this circuit the battery current is completely cut off. but the extra current flows in the same direction, and this reduces the secondary current produced by the break in the same way and to about the same extent as is the ease with the make secondary current. To bo accurate, the current through the primary coil is increased ItiO MKDH AL KLF.CTKK ITY AND KONTy the Hclniholtx typo of electro- magnetic interrupter; and while the induced currents are approximately equal. thi< is accomplished l>y reducing the l>reak secondary current to al>out the strength of that occurring at the make (Fig. 1'2'.>). The induct i vi- etTect is. t here fore, a weak one, and to secure t he usual farad if strength of application it is necessary to use a primary battery yielding seven or eitfht volts. An extra resistance in the battery circuit will gen- erally be found necessary with this type of interrupter. There is a urnwim: belief that the faradic current, with its high- tension discharge, is not so good even in its own particular field of an excitoniotor as i he rapidly interrupted voltaic cm-rent. The faradic coil, however, is of so simple a-nd inexpensive a construction and is operated by so small a supply of current that it will long continue in !_".. I'-ual type of primary waves in faradic coil. use where an inexpensive and readily portable apparatus is required TO -imply excite muscular contraction, as in the treatment of paralysis. ( MM- of Lewis .lone.-' experiments shows the effect of great frequency of interruption in a faradic coil with an iron core, and consequently a loiiii duration to the make and break currents in the secondary coil. This is illustrated in Fig. lij(), where we see the make current suddenly cease and change to the break current. The break current is "treading upon the heels of the make current." The lower line in this diagram repre-ent- the make current and the upper line the break secondary or iin luce. 1 current . The importance of the character of the interruptions in any current . i.- applied directly to the human body lies in the fact that muscular factions d" not occur durimr the passage of a continuous current. in t In' -iTondary roil \vhrn tlirrr '.ire too rapid intrrnnitioi rm and flow- in one dire. lion. They are u>uallv in tin- strength or direct ii MI of the current or hv inii the current, and in this way remind one of the n -h ' 1 1 i-ii ' . : : ' nts are induced in one mil ol v ire b\ current s ' . \\ it ! in ten ipi eil current s t he if real esi effect iii excit iim ' 1)1 i- produced when the current flows during a larif>' Thi- ha- been tested by Lewis .1' mes, v, ho of L'L' volt- \va- I he weakest thai would excite \ hen t he current HI i wed "til v ,,,',-,,, of a period, or ' ' ' ' . cula r ci nit fact ii >n i! the IMI rrent ; lerii >d. or 1 1.1 H 1 1 -econd. l-'uri her ci inH- O to b IS one ables us to compare the alter- cyclcs in a M nating electric current with the of the 1 tide. The in one 1 direction at a maximum rate 1 of 50 coulombs a second corresponds to the 1 six hours or so during whie'h the 1 tiele 1 is running up stream and the water is flowing at a maximum rate of say 50.000 gallons an hour. At f in Fig. 132 the elevtric current has become reduevd to zero, and then begins to incivase 1 with eemal rapidity to a strength of 10. 20, 30, 40. and 50 amperes, which it ivaches at d. From this point to c the 1 curves! line represents ._ M ' MI seconel, during which the effective or we 1 might say. les- technie-ally, average 1 intensity of the cunvnt is about 37 amperes, and at the' end of this time 1 a change occurs by which the eliree-tion of the current is again ivverseul, ami at b we 1 have 1 completed one 1 eye-le of this 11 11)2 MKDIl AL KI.KCTKHITY AND HO.NTCJKN HAYS alternating current. This is a sinusoidal current, so culled because its uraphic curve makes what is icnucd in uvomctry a sine wave. As in the effect produced in various therapeutic applications, these transitions are so abrupt that the current may he regarded as completely interrupted as well as reversed at each alternation. For our purpose, then, this current may he represented as in Fitr. loo. by a series of dis- connected horizontal lines, alternately above and below the neutral line. Fach line, ,/ < or amperes in this particular case, for ._,,',,, second in one direction or the other, n < and '/ < constitute the two parts of the complete cycle a to l>. A current of the character indicated in Fig. loo is an extremely effective one. both in inducing current s in other wires and also in pro- ducing phy-ioloiiic effects. I ts potency in t he latter particular makes it a much more daimerous current to handle at hiOOO times a secojid the current ceases to produce muscular con- traction and acquires the properties associated with high-frequency current s. '/At. d / rt ijin nr// i if fin nlli runt! ni) rum nt i- 1 he number of cycles completed in a second, o'O cycles are ed for liuht iny and powei 1 . 20 cycles for power transmission. For !i_uhtitm. anything as slow as 2") cycles w< mid cau.-e visible flickering. l:"icfn'i 1,1/1,1 nj nn nit, riKif/'riii cum ill i- that value in amperes which 1 produce the same heating effect as will the same intensity (or amperes ot direct current. Alternating current meters indicate the ive value. The act ual value of r he alternat inn; current is. of course, v chanirinir, and too rapidly for the eye to follow anv meter \\ Inch iin lic.ated it . i { effect ive value M '/./' m inn i nl in iij an nltcrnnti tui current = - 0.707 Forms Under Which the Alternating Current is Used in Medi- cine, i:. i' - ' : ;L r :!i:d unmodified form it i- used for diagnostic iilumina- i '.'' . elect i'ic bat hs, and lor 1 he induct ion o; hitih -tension frequency current.-, and for the induct ion '.'- lor cautery purposes, and to run electric motors : - . --. '' vari< iiis levin s < >r. rat h( r, i 1 - > \ av be '''' : ' . -a direi-t current, a sinusoidal current, a polv- Alternating Current Transformers, Step-up and Step-down Transformers. T!.- al'< n ! in:: elect i ir-liirht current , wit h itschaii"'e DYNAMIC ELECTRICITY 1(13 from, say, f>0 amperes in one direction to 50 amperes in the other direction every ._,',,, second, is an ideal one to induce secondary current-. This is all the more true because it has been found that no accessory apparatus is required, simply a primary coil and a secondary coil, both surrounding a soft-iron core. The principle is the same as in the in- duction coil, but the variations in the current are supplied ready made by the dynamo, and no interrupter is needed and no condenser or other contrivances, such as are necessary in the case of an induction coil. The secondary currents are of any desired voltage, dependent upon the number of turns in the two coils. If there are twice as many turns of wire in the secondary coil as in the primary, the voltage of the 'secondary current will be twice that of the primary current. Or, if the secondary has only , ^ as many turns as the primary, the secondary current will be of only V J- the voltage of the primary. A very important fact, also, is that the amperage of the secondary current undergoes equal but opposite variations, so that in proportion as the secondary current increases in voltage it diminishes in amperage, and vice versa. The same amount of energy is generated in the form of a high-tension current of low amperage or of a low-tension current of great amperage. The best transformers yield a secondary current whose energy is equal to 97 per cent, of the energy required to send the current through the primary coil. The simplicity of the apparatus, two insulated coils with an iron core, which requires no moving parts, and the fact that it can be constructed to transform the 110 or 220 volts alternating electric-light current into a low-tension current of great volume for cautery purposes, or a high-tension current of small volume for .r-ray and high-frequency applications, makes the transformer exceedingly Fijr. 134. Caut valuable. The heating effect of the current is dependent upon its volume or amperage. Fig. DM shows the form in which a transformer is often used for cautery purposes. It consists of two separate coils of insulated wire, one of which ills inside the other, bin the number of its turns traversed by the primarv current may be reduced if it is desired to reduce the strength of the secondary current. The inner coil contains an iron core. It is a *t< [)-, B. tt S. gauge, will become incandescent or even white hot from the passage of a current of 1 volts and 10 amperes, and make an excellent cautery. The same energy as a current of 110 volts and 0.4 ampere would not heat t he wire percept ibly. A current of 1 10 volts and 10 amperes would produce the >ame healing effect upon the platinum wire, and this could be obtained from the electric-light circuit, but there are two important reasons why it is better to use a step-down transformer: one is that it would be dangerous to take a current as strong as 10 amperes from one of the 110 volts electric-light sockets; there would have to be -pedal wiring of the house and fused knife-switches at the outlet to prevent damage from lire, just as in the case of the heavy currents used for the .r-ray. Y\ hen we remember that for some purposes, a cauterv current of !~)0 or even SO amperes is used, the employment of the 1 Ill-volts current is seen to be out of the question. The trans- former enables us to use a current of only O.o ampere and 110 volts, and convert it into a cautery current of 10 amperes or more. It is, therefore, practicable to attach it to anv ordinary alternating current light socket. The second reason why the transformer is regarded as necessary to lit the alternating electric-light current for cautery use is the danger and discomfort to operator and patient from handling and applying an uninsulated wire charged with an alternating current of 1 Id volts. The Production of the Secondary Current in an Alternating Current Transformer. Kadi time the primary current begins to flow in a direction which we will call A, a current is induced in the secondary coil and in an opposite direction to that in the primary. \Yhen the current ceases to flow in the direction A in the primary, a current in the same direction is induced in the secondary coil. These are exactly analogous to the make and break currents in an induction coil. In the case of the alternating current there is another element. At the instant that the primary current ceases in the direction .1, it be- gins in i he direct ion 11 . and t his induces a make current in the secondary a direction contrary to It. or, in other words, in the direction .1. two forces tend to produce currents in the secondary <\ them in the direction .1. The two forces are the oinotive forces due to the break of the primary current, i' of the primary current. H. The result is the induction 'condary current in the direction .1. At another part 1 make ot the primary current .1 and the break of the /: re simultaneously operative in producing a sec- i the direction /<'. The alternating currents, .1 and II. join forces in the production of an alternating [he secondary current may be of the same char- , current, and present a series of currents of full direction and then in the other, with .-udi a sharp ie t v. o as pract ically to cause a break in the cunvnt . -dl-ini luct ion m the primary and secondary coils inductance coil introduced m the primary circuit' may be so regulated as to produce a current analogous urretit. A chart ot the secondary current might 'iitinuou- curve extending alternately above and below DYNAMIC ELECTRICITY 105 the neutral line, and undergoing much less abrupt transitions than those seen in a chart of the alternating electric-light current. Such a sinusoidal current, adjustable at from 5 to 30 volts, is of value in thera- peutics, except in cases where a unidirectional current is required, as for diagnosis or for electrolysis. This type of step-down transformer has greater efficiency than if the two coils were straight and open at the ends, this fact being due to the energy wasted at the two open ends of each coil, just as the greatest efficiency in an electromagnet is not obtained in a straight bar. The magnetic flux in the latter case is carried partly by the iron and partly by the air. through which it effects a return to the first end of the iron bar. The quantity of magnetic flux and the weight-bearing attraction of the magnet are not so great with this as with the complete ferric type of magnet, of which the horseshoe magnet, with its iron armature, forms the most familiar example. In the same way a transformer of the straight cylinder type wastes a certain number of expanding and con- tracting lines of force and is less efficient than the closed magnetic ring type of transformer. The straight type is simple in construction, and the strength of the current may be readily regulated by moving one of the coils out of or further into the other, and for most electrotherapeutic work the advantages offset the fact that it takes a little more primary current than some other types to yield the same secondary current. A utep-up transformer may present the same appearance as /^^^^\ _ s a step-down transformer, but it has a greater number of turns in the secondary than in the primary coil. The voltage of the secondary current is pro- portionately greater, and may even be great enough to excite an x-ray tube or a high-frequency apparatus. These are, in fact, the principal purposes for which Fi - i:r. Diagram of a step-up transformer: ,. r J _ 1 P. Primary; -S, .secondary. a step-up transformer tor the alternating electric-light current is used in therapeutics. In both of these cases the maximum efficiency is desired and a closed magnetic, ring transformer is generally used. Fig. 13o shows in a diagrammatic way the construction of a transformer of this type. It consists of a complete ring of soft iron and two coils of insulated wire passing around the iron at the same or different parts of its periphery. One of these wires transmits the 1 10 or 220 volts alternating electric-light current, and is called the primary. The other wire has alternating currents induced in it by the action of the primary current, and is called the secondary. The ends of the latter are attached to the poles of an .r-ray tube or to any other apparatus through which it is desired to send an electric current. The voltage of the secondary current bears the same ratio to that of the primary current that the number of turns in the secondary bears to the number of turns in the primary coil. This type of trans- former may, therefore, be used as a step-up or a step-down, according to whether the primary current is connected with the coil having tin 1 smaller or the larger number of turns. In either case the efficiency of such a transformer is very great, about 97 per cent, of the energy !()() MKDICAl, KLK( TRICITY AND KO\T<;KN RAYS required to produce the primary current reappearing as energy in the secondary current. The energy required to send the exciting current through the primary coil consists of two factors. The first is that which is required to overcome the ohmic or frictional resistance in the primary coil. This would be almost the total energy required if there were only a primary coil. This is lost as electric energy and reappears 'he second is the energy required to induce the current in the coil. The secondary current performs work in whatever cautery, or .r-ray tube, for example, it is supplied to, and assuredly required to produce it. An illustration from may make this clear. A man may have to exert only a -mall amount of energy to turn a crank and cause a cog-wheel to revolve if onlv frictional resistance is to be overcome: but if the cog-wheel is ley by which a heavy weight is to be lifted, the so much additional energy in order to make the coi^-wheel revolve. The additional resistance to the revolution of the cog-wheel winch the man must overcome is the torce exerted by the heavy body tending to cause the cog-wheel to revolve in just the opposite direction. Returning now to the transformer, the secondary current actually does exert a torce tending to produce a current in the primary coil, which would be in the opposite direction from the primary current. This opposing force to be overcome in the primary coil is called counterelect roinotive force. The actual ring shape i- not essential to the closed magnetic ring transformer. It i- often better to have it made up of many separate narrow iron plate- riveted together so as to iorm a hollow rectangle. Tin.- is very easily constructed and the winding of the two coils of wire about the iron core is greatly simplified. In fact, the coils are wound separately and then the proper section of the core slipped inside of them before being riveted to the other sections. In sonic cases the primary and secondary coils are wound about different parts of the circum- ference of the magnetic ring, and in other cases one is wound directly over the other, as in the case of an induction coil. The same precaution as to in -11 hit imi inu.-t be t a ken as wit h an induct ion coil of equal voltage. in transformers are usually immersed in oil. which has mvenient and highly effective insulating medium. in addition to the insulated wrapping placed around i a coil. -toriner i.- of an alternating char- an iin luct i< ni coil in being equal in ly well adapted to .r-ray purposes, (pressed, or 1- requires special luct |i in ci ill. Int hi \\'e a ker than t he cial apparatus has t foill >lesi line, very - 1 it . Tims, t he in! n r-ray coil will usua rehit ive \\ rakness of 1 he which will pass acn iss 1 h all- U Illch i.- i >I1 en effect JYi t ioll of I he self-ill! lllct ji ill DYNAMIC HLKCTHICITY 107 coil by varying the number of turns through which the current is sent. Varying the different connections of the x-ray tube itself, an anticathode and accessory anode and vacuum regulator will often accomplish the result. These various measures prove ineffective in the case of a step-up transformer for the reason that the currents are similar and equal in both directions, and these various procedures would have about as much effect upon the currents flowing in the desired direction as upon those in the opposite direction. The alternating current trans- former without any modification has been used to actuate 1 an x-ray tube, and was thought fairly satisfactory until the induction coil was brought to its present state of efficiency. The recent work of d'Arsonval and (laiffe has resulted in the application of devices for suppressing one set of impulses from the transformer. Snook and others rectify the secondary current. These two devices result in the production of a cur- rent so uniform, efficient, and so easily regulated that the modified trans- former is probably the best .r-ray apparatus in existence. It requires no interrupter. It works upon the alternating electric-light current, and has such advantages over the induction coil as to render it desirable even where the supply current is of the direct type. In the latter case a motor generator or a rotary transformer operated by the direct current is employed to produce the alternating current for the trans- former. This adds somewhat to the cost, but very little to the care of the apparatus. The most essential points in the suppression of one set of impulses is the presence of two ventril or valve-tubes connected in series and forming a shunt circuit between the two poles of the coil. Each ventril tube is a vacuum tube with electrodes of two different characters, one of which will readily act as a cathode and the other will not ordinarily do so. Secondary currents can pass through such a Fig. l.'iG. Parallel arrangement of ventril tubes. ventril tube without hindrance' in a certain direction, but with the greatest difficulty in the opposite direction. Introducing one or. as in (laif'fe's apparatus, two ventril tubes between the poles of a trail former has the effect of affording a short and direct path for the sec- ondary currents in one direction while having no effect upon those in the other direction. The two poles of the transformer, therefore, transmit to the .r-ray tube a uniformly interrupted series of secondary currents which are all in one direction. Figure liW shows the gener;d arrangement of these ventril tubes; /> and // are the two poles of the transformer and the two ventril tubes are arranged so that the current.- ItiS MEDK-AL ELEITKK'ITY AND K(")XTc;EN T RAYS enter the corresponding end of each tube, the positive end of one tube U.in.r connected to tin- negative end of the other by a conducting wire; // which is marked +. is the pole which is to be connected with the mode or positive terminal of the .r-ray tube; and />, which is marked i* to be connected with the cathode of the .r-ray tube. Negative impulses from // pass readily through the ventril tubes whose cathodes are both nearest //. but negative impulses from /> find a tremendous resistance to their passaire through the two valve-tubes, .lust a word as to the construction of a ventril tube may not be out of place. It IMLT. 1H7. Scries arrangement of ventril tubes. ut i- a tube of about the same degree of vacuum as an .r-ray tube, and .-tiould lc provided with a means of regulating the vacuum. The type shown in the illustration has two leading-in wires, one of which terminate- in a small aluminum electrode, and the other in a long spiral of aluminum presenting many times the surface area of the first. The high-tension current used for /-ray work encounters very little resist- ance when pas.-iim in Mich a direction that the cathode is the electrode with very large area, but is arrested when the polarity is reversed. negative current will pass from the long spiral electrode to the it will not pass in the opposite direction. A different. been made of a ventril tube, placing it in series with so that it will allow the current to pass through it to in the proper direction, but will act as an insuperable in the opposite direction. The ventril tube is permit the passage of the direct discharge from ugh the /-I'ay tube and to obstruct the inverse e current which the ventril tube transmits the ventril lubes are used to shunt or will readily transmit, and to leave ass immediately from the poles of the This i- probably t he best arrangement. on p. "s'.i. The Henifar self-rectifying he inverse discharge from an induction ci ified siep-up transformer with the possible addition of a series th DYNAMIC ELECTRICITY 169 former in one direction sufficiently we may have an x-ray generator without moving parts and much simpler and cheaper. The Coolielge x-ray tube is self -rectifying to a great extent. A question naturally arises as to the much fewer cycles of this secondary current, but it is probable that the same voltage and milliamperage will produce approximately the same effect as with the present more fre- quent cycles. Gaiffe's apparatus for the employment of an alternating current transformer for x-ray work includes liquid volt controllers, condensers, and other appliances which will be described on another page. The whole combination is a practicable thing, whereas a simple transformer is not perfectly adapted to the purpose. Snook's and similar transformers with a rectified high-tension discharge are further discussed on p. 746. DETECTION AND MEASUREMENT OF ELECTRIC CURRENTS General Considerations. Sources of electricity are really means by which an electromotive force is produced, or a difference in potential is created between two points. This is known also as the tension of the current and is expressed in volts. It produces a flow of electricity through any conductor uniting the two points. The current has a tendency to establish a neutral condition by equalizing the electric state of the two points, and is analogous to the flow of water from a higher to a lower level. The amount of electricity transferred in a second is the strength of the current, is called its intensity, and is expressed in amperes. The rate of flow or the intensity of the current is determined by two factors the tension of the current and the resistance of the conductor. It is directly proportional to the tension or voltage, so that if the voltage is twice as great, twice as many amperes of current will flow through the same resistance. It is inversely proportional to the resistance, so that if the resistance is twice as great, the same number of volts will cause only half the number of amperes to flow. All substances will transmit electricity, but some, including most metals and many liquids, do so with so little resistance that they are called conductors, and are used for the purpose of transmitting electricity. Other substances are poor conductors. Still others are such poor conductors of electricity that they are called non-conductors, and are used as a means of insulating bodies which are charged with electricity or which are conducting an electric current. In the case of a very good conductor, like copper wire, there is, nevertheless, a certain amount of resistance, and a certain proportion of the current seeking to pass through it is changed into heat by an effect analogous to that of mechanic friction. The ohm as an absolute stand- ard of electric resistance is the resistance 1 at a temperature of 32 F. of a column of mercury one square 1 millimeter in cross-section and 100.3 cm. long. The coulomb as an absolute 1 standard of elect rie 1 quantity is the 1 quantity which when passe'd through a solution of nitrate 1 of silve>r will cause 1 1.1 IS milligrams of metallic silver to be 1 depe>sited. The ampeMv as an absolute 1 unit of cunvnt flow e>r intensity is a eurrent e>f one coulomb per seronel. The 1 volt is not an absolute 1 but a composite unit e>f potential e>r tension; it is an e'le'ctromotive' fore-e whie'h will e-ause- a e'urrent e)f erne 1 ampere 1 to flenv through a resistance of one 1 ohm. A Daniell cell produce's an electromotive force of about 1.08 volts. 17H Mi;i>I< AI. KLK< TKKITY AM) RONTGEN RAYS Ohm'-- Inn- is of fundamental importance: ( '; : iff [] CK: or H *,' . It means that the intensity <>f the current in amperes is equal to the electromotive toive in volts, divided by the resistance in ohms. One or uvo examples may l>e given. If the electromotive force is 110 volts and the resistance 10 ohms, tin- current .-tivng'th \vill be 1 1 amperes: " am P eres - I:' the resistance is 1 ohm and the intensity or strength of current flow is 10 amperes, the potential or tension is 10 yohs: i: <'!!: I! - 10 X 1 = T) volts. K R = 40tj.()(J(i ohms. 0.01 .) Values oi I!. I-!, and (', about like those in the last example, are found in the application of the voltaic current to the human body. '1 In values in t he tir.-t example. 110 volts, etc.. are like those sometimes f"und in ./'-ray work: and those in the second example. 10 volts. 10 ai > res, and 1 ohm. are like those occurring in the use of the galvuno- caUt 'TV. These relations an- universally true, although either K or R may be a composite instead of a simple quantity. The measurement of electric quant it ies. st rength of current, potential, or resistance almost invariably d- I" nd- upon the application of this law; and the construction of all ' -t ric : pparatus is guid'-d bv it . Th- voltameter i- an instrument by which the quantity of elec- tricity which ha- (lowed in a given time i- measured by the increase in ol a -ilver plate from tin- deposit ( ,f metallic silver upon it. in-'rument is really a measurer of coulombs, because the quantity r deposited 1.1 Is milligrams) is t he same for the same number of coulomb- whet her i he current is at t lie rate of ] coulomb per second or 1 coulomb p<-r minut'-: that i-. 1 ampere, or ( .' (| ampere. ''tie coulomb liberate,; \-_> ,..,.. , ,f hydrogen gas. A water voltameter d in cubic centimeters, or directly in coulombs. The Centimeter-gram-second System of Electric Units.- The tii'-'fi i- the np-fric unit of length, and i- equal to 0.:->7o ( .l inch. jilt in the -ame -y-tem. and i- the weight ' ri til iin iter at 1 < '., the temperature at which water '\'\. <<''' \- ' he unit of t hue in t he same - m. luce- mot ion or change of mot ion in a body. ' ' '! torci . and acting for one -econd upon DYNAMIC KLKCTKHTn 171 a body weighing one grain, it will give the body a velocity of one centi- meter per second. \\'ork is the product of a force by the distance through which it acts. The ('. (i. S. unit of work is the crtj. or the work done in overcoming a force of one dyne through a distance of one centimeter. A concrete example of work is the raising of a bodv weighing one gram to a height of one centimeter. Since the attraction of gravity acting on a mass of one gram for one second will give a velocity of ( ,)S1 centimeters per second, the force exerted by gravity upon a body weighing one gram is ( .)S1 dynes. Therefore, the work done in raising a mass of one gram to a height of one centimeter is OS! ergs. Other units of work are the kilogram-meter =100,000X981 ergs, and the foot-pound 1 .856 X H) 7 ergs-- 13.56 million ergs. Kindle rncn/i/ is the work which a body can do by virtue of its motion. Potential ener(/t/ is the work which a body can do by virtue of its position. The unit in either case is the erg. The unit of the rate of work is one erg per second. A horse-power = 33,000 foot-pounds per minute is 7460 million ergs per second. The horse-power represented by an electric current is equivalent to the , IT ' ( <2 R !v' . . . electric energv or - ._ or -_,.,- or -_ .. , in which expression h = /46 /46 746R volts, (' = amperes, and R = ohms. One horse-power is f kilowatt or 740 watts. One kilowatt is 1.34 horse-power. Electric units are derived from the centimeter-gram-second system. There are two sets of them the electrostatic and the electromagnetic systems. The electrostatic system has for its unit of quantity the amount of electricity which will exert a force of one dyne upon a similar quantity of electricity at a distance of one centimeter. The force will be one of attraction if one charge 1 is positive and the other negative; and of repulsion if both are of the same sign (4- or ). The electro- static units of current, electromotive force, and capacity are derived from this unit of quantity. The electromagnetic system of ('. (1. S. units is the one that is commonly in use, and is based upon the force exerted between two magnetic poles. For instance, a icnit tnni/ni'tie pole repels a similar pole at a distance of one centimeter with a force of one dyne. The C'. (i. S. unit of current is a current which, passing through a wire one centimeter long, bent into an arc of a circle whose radius is one centimeter, will exert a force of one dyne upon a unit magnetic pole situated at the center of the circle. The C. G. S. unit of (jiiantiti/ is the amount of electricity transferred in a second by a current of a strength of one unit. The ('. (1. S. unit of electrotnotire force is that which must be maintained between the ends of a conductor in order that a current of unit strength shall do one (\ (i. S. unit of work in a second. The C. (i. S. unit of rexfxfttnci' is that of a conductor in which a unit of current is produced by a unit of electromotive force. The C. (i. S. unit of capacity is t In- capacity of a condenser which will be at a potential of one unit ot electromotive force when charged with one unit of quantity. Practical Units of Electricity. The electric units in every-day use are arbitrarily selected, and are of a size to be readily measured, so that the currents ordinarily employed can be represented by onlv a few units. The comparison between the ohm. for instance, and the C. < i. S. unit of resistance is about like that between the ton ami t he grain as units of weight. 172 MEDICAL ELKCTHICITY AND RONTGEN RAYS The conlnnih \< /,, ('. (i. S. unit of electric quantity, or 10 l C. G. 8. units. It decomposes O.OOOO'.tl") gram of water or deposits 1.1 IS milligram of silver. It is the amount of electricity transferred in a second by a current of one ampere. The nntr< is the unit of current or of the rate of flow of electricity. A current of one ampere transfers one coulomb of electricity pel 1 second. It decomposes 0.0000 ( .)l~> gram of water per second. It is equal to j 1 ,, ( '. ( I. S. unit of current . The militant f n is one-thousandth of an ampere. The rult is the practical unit of electromotive force, and is the electromotive force which will maintain a current of one ampere through a resistance of one ohm. It is equal to H) 8 C. G. S. units of electro- motive force, and is about 7 per cent, less than the electromotive force of a Daniell cell. The uhtti is the practical unit of resistance, and is equal to H) 9 C. G. S. units of resistance. It has been defined by international agreement as the resistance of a column of mercury 106 centimeters long, one square millimeter in cross-section, and at a temperature of C. or 32 F. No. 10 copper wire is 101.0 thousandths of an inch in diameter. A piece 1000 feet long has almost exactly 1 ohm resistance. T\\c ftir equal to the number of amperes multiplied by the number of vnlts \\ ('! Or. it i.- equal to the square of the current strength iii amperes multiplied by the resistance in ohms W = ('-H. Or it is electromotive force in volts divided bv the may. for example, indicate a cur- s, or a current of o amperes at a units ot elect ric ]>ower. watts acting during one hour, is a i- th<' unit upon which the electric- ' he use of t he current . It may. in an hour by a current of 10 er t han i me kilowat t act inn -mailer current for a longer or work upon which tin DYNAMIC ELECTRIC 'ITY 173 C. G. S. units of work. It is found to he the amount of heal necessary to raise 0.2405 gram of water one degree Centigrade. The caloric is the French unit of heat, and is the amount of heal required to raise the temperature of 1 gram of water 1 C. It is analo- gous to, but much smaller than, the Knglish heat unit, the pound-degree. For the amount of heat generated by an electric current see page 202. Dynamic electricity produces measurable physiologic, chcmic, me- chanic, and physical effects. Under the latter head would be included thermal, luminous, and magnetic effects. The magnetic effects are es- pecially available for ascertaining the presence and strength of electric currents, and will be the first to be described. ELECTROMAGNETIC GALVANOMETERS Oersted's initial discovery in regard to the intrinsic relation be- tween electricity and magnetism consisted in the observation that if a current of electricity passes through a wire passing above or below a . Principle of the needle galvanometer. magnetic needle like a compass, the needle tends to place itself at a right angle to the wire. As to direction, if the current is above the needle and is passing from south to north, the north pole of the needle will be deflected toward the west; if the current is from south to north and is below the needle, the latter is deflected toward the east; just the opposite deflections occur if the current is flowing from north to south (Fig. 138). Figure 139 represents the case 1 of a galvanometer with a single needle a-b, and a current flowing through a single complete turn of wire. The current passes from south to north, above the needle and returns from north to south below the needle. Hoth pails of the loop, there- fore, carry a current which tends to make the needle swerve to the west. The angular distance through which the needle moves depends princi- pally upon the strength of its magnetism (which tends to keep it in a north and south direction) and upon the strength of the current. I'sing the same needle for different observations, the apparatus will serve a> a measure of the strength of the cunvnt. The strength of the effect 174 MKDICAL ELECTRICITY AND KONTCKX RAYS upon the needle is multiplied by using a coil of many turns of wire instead of a >ingle loop: and the sensitiveness of the needle is increased by making it a-tatic. Thus, Fig. 1 H) consists of using two magnetic needles fastened to the same vertical axis, one with its north pole pointing in the usual direction, but the other with its poles reversed. Both are suspended by a silk thread and the coils of wire pass around only the lower needle. The effect is the same as it would be upon a needle of the si/e of both combined, and with the magnetism of both combined, but opposed by the influence of the earth's magnetism only to the extent represented by the difference between the strength of the two needle<. These must not be exactly equal. If they were there would be no force opposed to the directive influence of the electric current, and weak as well as strong currents would cause the needle to assume a position at right angles to the plane of the wire. This would destroy its value as a means of measuring the strength of different currents. Tin' strength of the current is indicated by the extent of the angle of deflection. It is difficult to calculate this from purely theoretic data, and these instruments are usually graduated by comparison with standard mst rument>. The resistance of a galvanometer without its shunt is usually from 100 to (100 ohms. The d'Arsonval milliamperemeter and several other types of electro- magnetic galvanometer in common use are described on pages 189-193. Hot Wire Galvanometer. This depends upon the heating effect ot an electric current upon a fine wire through which it passes with considerable ohmic resistance. The hot wire expands and allows the pointer to move across the dial under the influence of a spring. It is applicable to alternating and high-frequency currents, as well as direct currents, and to almost any voltage. It is difficult to secure great accuracy with an instrument of this type. It does not indicate t he direct ion of t he current . The Capillary Electrometer.- --This is an instrument which is useful in measuring the electromotive force or potential differences urrents in animals 01 r pat h< il< >iric elect ric curn I' i- very sen-hive, thouu-h not so sensitive as a galvanometer 1(1 made. It ha- the advantage of giving accurate measurements DYNAMIC ELECTRICITY 175 of the electromotive force, even of a voltaic couple of extremely great internal resistance. This is the condition in physiologic and pathologic currents, and is not so perfectly met by a galvanometer. The capillary electrometer acts under these conditions of small electromotive force and very great internal resistance practically in an electrostatic manner. Lipmann's capillary electrometer (Fig. 141) is based upon the influ- ence of electricity upon surface tension and capillary attraction. A glass tube, the lower part of which is of capillary caliber and dips into a jar of dilute acid, is open top and bottom and has its upper part tilled with mercury. Under these circumstances the mercury does not run out of the tube, but rests at a certain level upon the surface of the dilute acid in the capillary portion of the tube. As usually con- structed, this level is above the general level of the solution in the jar. The level may be adjusted by changing the pressure of the column of mercury. Observations of the level are made with a microscope or an image of the capillary electrometer may be, thrown upon a revolving cylinder of photographic paper and produce a record of the variations. Connecting the mercury in the upper part of the tube with the negative wire and the mercury in the bottom of the large jar with the positive wire, the level of the surface at which the mercury and the acid solution meet in the capillary tube rises the moment the current is turned on. The difference in potential between the two masses of mercury is pro- portional to the height to which the level rises or also to the mercurial pressure required to maintain the original level. This form of electrom- eter is extremely sensitive, responding to even the weak currents characteristic of animal electricity, and is instantaneous in its response to such currents and in its return to the zero mark after the current ceases. It is used in many physiologic experiments, such as the measure- ment of muscular currents. The Siring Electrometer. Einthoven s string electrometer is based upon the fact that when a current of electricity passes through a wire tightly stretched in a powerful magnetic field the wire is deflected toward one of the poles of the magnet. A powerful light and a high-powered photomicrographic apparatus are used to throw an image magnified 250 times or more upon a moving strip of bromide of silver photographic paper through a slit which is at right angles with the length of the wire. The string or wire originally used by Einthoven consisted of a filament of quartz obtained by directing the flame of a blow-pipe upon a piece of quartz fastened at one end and having a heavy weight suspended from the other. The silvered quartz thread was one-third the diameter of a red blood-cell. The electric resistance was about 10,000 ohms. The apparatus improved by Xicolai and Huth (page 324" employs a platinum wire about 4 inches long and having a resistance of 0000 ohms. In either case the electromagnet must be a powerful one and in Nicolai's apparatus weighs GO pounds. It must be actuated by a direct current, either from the electric-light circuit or from a storage battery. Correction for Internal Resistance in Measuring the Electro- motive Force of a Voltaic or a Storage-cell during Discharge. It is not sufficient to determine the difference in potential between the two poles of the batiery by means of a voltmeter or a potentiometer. The number of volts found in this way while a current is passing through the batterv must be corrected bv taking into account the fact that the 17() MKDK'AL KLKCTKICITY AND KONTCJKN HAYS resistance of the electrolyte in the battery cell through which a current is passing will in itself require a difference in potential equal to the current multiplied by the internal resistance. This amount in volts i> to be added to the measured difference in potential between the two poles to find the total electromotive force of the cell. Another condition remains to be considered. In the case of a battery with a certain number of volts difference in potential between its poles the current passing through the external circuit is equal to the voltage at the two poles, divided by the resistance in the external circuit. Rut doubling the external resistance does not cause the current to lie just half a- great. In order to reduce the current one-half, the total resistance, internal as well as external, must be doubled. The difference in potential at the two poles will be found to have undergone a change if only the external resistance is varied, and the new strength of current cannot, therefore, be calculated from the old voltage at the two poles. The new voltage may be measured by a voltmeter or a potentiometer, and then this may be divided by the new resistance of the external circuit to obtain the number of amperes of current. The total electromotive force divided by the total resistance always gives the strength of the current; and whatever the intermediate voltages or resistances may be. their effect is determined only by combination with the conditions in the remainder of the circuit. The current from a single storage-cell with an external resistance of ,,,',,, ohm maybe 10 amperes. And this would indicate two different things. One is that under the conditions described the potential difference between the poles of the battery is only T J-jj volt (Y = ('R or ,/,,-, volt- 10 amperes x TTnro - otim, according to Ohm's law). This is true in .-pile of the fact that on open circuit or with a large external resistance the potential difference between the two poles of the cell will be _> volts or over. The other fact, which is indicated when the current produced by a known electromotive force of about 2', volts an external resistance of only yj, 1 ,,,, ohm is only 10 amperes, is that unvnt Mrength must in this case be almost entirely determined by internal resistance of the storage-cell. If it depended only on the resistance, an electromotive force of 2 1 , volts would nt of 2")00 amperes. This will be found to be of impor- ect ric currents produced by physiologic processes, tential between two portions of the body may be se are joined by a conductor of 1 ohm resistance, 11 OS volt - 0.0X0 ampere, or SO milhamperes, 1 ohm Vt 'i' v much weaker one. The resistance of the body may bo HIS or more, and this must be added to the external resist- cal'-iihiting the -trength of the current. The total elect ro- t"t'ce may in this way be approximately the 0. OX volt difference ; i 1 !: i 1 }','<" 1 it . / >lif I'd/I 1/1 in/ (it n Si/n/li i'J t rtrotlc. This finds ation in the case of *t<;oo - o. (i.'-UK) = -0.0700 volt. Known Potential of Calomel Kloctrode Difference in Potential = Unknown Potential. Hence, Potential of Calomel Klectnxle. Difference in Potential. Unknown Potential. ~o.r>() -o.oTOO Another example would be: Potential of Calomel Electrode. Difference in Potential. Unknown Potential. --().. ")li()0 ().,")()()() - O.OtVK) n 17S MEDICAL ELECTRICITY AM) RONTGEN RAYS source of potential. The difference so found may be regarded as the potential of the calomel electrode in the different calculations. '/'//< //, induces a current in the irst describ -d. and the effect of this at is to dl! ' e an racl i' >n exerl -'d upon the iri 'ii dia- . I hi 11.- i ' vibrations produced bv the sound of 1 he 1 ( at thi ! ram-mi* ler are accurately duplicated by the . '1 he vil il'al !' 'li- ' 'f the la! " -T are ci immimi- sound.- '.'. hicll are jin all:, i '-1 perfect repro- : . ' ' . ' ' , Ice. \11 elect i'ic bal !er\ ; - \ . ry I'ommonlv ; . ! ' ->-' c l iiiii is ciirrenl i t he coils in t he / ' , ' wire as soon as ' '! I ; , '. ' < : " used. The magnets an 1 l he current . and l lie i li't 'ct in t he 1 ratiM! ;' ' r i- to > >p n luce 1 Hi . I he-e v; riat ion- are ri ( >eat ei 1 : ici vana' ion- in ' ie -t r ngl h of ' . !> i ions of i liap iragm. This ' permanent magnets in - I an v bai i ei'v. Thi use of the telephone a- a delicate test, for the proence of DYNAMIC ELECTRICITY 179 electric currents makes it valuable in measurements of resistance and of electromotive force. It is invaluable for rapidly alternating voltages, for which the various types of galvanometer and electrometer are unreliable. The telephone will detect differences as small as T o,VoT) between the potentials of two objects. This is illustrated on p. 185. The Telephonic Build J'robc. Dr. John H. Girdner, of New York, was probably the first to publish a description of such an instrument. A telephone receiver has one of its wires connected with a metal bullet probe which may, but need not necessarily, be insulated except at its tip. The latter is of metal. The other wire goes to one pole of a battery of two or three voltaic cells or to one pole of a small induction or faradic coil, the other polo of which may be held in the patient's hand. The electric contact is decidedly bettor or the resistance; less when the probe touches a piece of metal, such as a bullet embedded in the flesh, and a sharp click heard in the telephone receiver announces the fact. This method has been applied by Kenneth Bulkley, 1 who attributes the telephonic bullet probe to Alexander Graham Bell. 2 He uses only the bodily currents of electricity, no battery or generator of any kind. The telephone receiver covering both ears has a resistance of about 1200 ohms. The probe is a steel darning needle insulated by shellac except at its point, and is intended to pierce the tissues in various directions until a sudden click indicates lessened resistance and greater current on making contact with a metallic foreign body. The other electrode is a carbon pencil placed in the mouth or rectum. Ax a Text for Hearing. Urbantschitsch has devised the apparatus shown in Fig. 143. This consists of a telephone receiver, which the l-'ij.'. 143. Urbantschitsch's trlrphonc apparatus for tilting hearing. patient holds to his ear, a secondary coil, with which the telephone is connected and which is placed inside of two separate primary coils. The latter are exactly similar and are supplied with the same current from a battery or from the electric-lighting circuit, the interruptions being made inside a sound-proof box. When the two primary coils are in exactly the right position, the effect of one upon the secondary coil exact Iv 'counterbalances the effect of the other, and there is eom- 1 Sun:.. ( iyn., ami < >bst., March - The Lancet, London. 1 ^i, 1. 1 ISO MKDICAL KLKCTHICITY AND RONTGEN HAYS plete absence of sound iii the telephone, (hie of the primary coils is fixed, hut the other is movable by a rack and pinion. Moving this coil toward the center of the secondary coil causes more and more secondary current to l>e induced, and more 1 and more noise to be produced in the telephone. The point at which the patient is able to hear the sound furnishes a mat hematic value for record or comparison. It is possible to u-e a single primary and a single secondary coil in the same way. but they would have to be separated to an inconvenient distance in order to secure complete absence of sound. \\ith the two primary coils only two or three inches of motion are required to change from the maximum sound to complete silence. Fiii'iire 1 1 1 r-fork set in vibration by an electromagnet and inclosed in a sound-proof box. The telephone is excited by the secondary current- in an induction coil, the primary wires of which are not con- 1 14. -Bn-ii ung's telephone apparatus for testing hearing m-eted with any battery, but with electromagnet coils placed near the vibrating end- of the tuning-fork. The back and forth motions of the -tee] tuniiiL r -fork generate alternating currents in the primary coil. The loudne--: of tin- -oiind in the telephone is varied by moving the secondary ( '"il nearer to or further from the primary. The advantage of thi- over the other m-trument is in the fact that a pure tone is pro- duced or sound coii-Minu: altogether of one wave length. ( 'ases o| deaftie-s are sometimes benefited by the application ot -ound vibration- by means of such apparatus as the telephone 1 or the phonograph. Thi.- may be called a very mild form of auditory nin+.-H'ii . The Electric Conductivity of Liquids. The rt>nrli/cfirit>i of a liquid i tin ' tmber o] amperes ni current \\hidi a cube of the liquid me;i-uriii . li)-'' 1 . or o.ooooo"). The slightest admixture ot any readily elec- tn>ly/.able substance multiplies the conductivity of water enormously. The product- of electrolysis collect upon the two electrodes and have a tendency to greatly increase the resistance, especially if one or both products a.re gaseous. The Wehnelt interrupter is an example of a -Mi I bridj* I i- lt.">. -Use of the alternating (.h'ctru'-light current in testing conductivity of a liquid. it iiitruller ari'i th<- \Vheat>ti>ne bridge are in series with the incandescent lamp. liquid resistance in which the current is actually rendered discontinuous by change- taking place at one of the electrodes. The resistance of a liquid cell is, therefore, not always a true indica- ti' in of t he c, indue- ivit y < if t he liquid. The mjlut an nf fiftltirisntitin is reduced by using a rapidly alterna- '::.:: current and electrodes with -penally prepared surfaces. Platinized electrodes are prepared by immersing them in a *> per cent, solution ot platinum chlond containing - 4 l n per cent, lead acetate, and -ending :i weak curr<'iil of electricity at first in one direction and then in the other tor about ten minute-. The surface ot the platinum electrode- become- coated with platinum black, which does not allow ilate upon its -urtace to anv extent, and thus greatly e- po] i/.ation. Palladium black deposited upon the surface ol the e]i-c!i n|i-- i- a]-" an excellent depolarizer. [lap ' :, ol the current, -o that neither electrode is of one p . i';. . :.'-' '] iirh for gases lo collect upon it. is a most effective mead of pn i/.a! ion. /'''"/ '' . ';/ " LI 1 1 a nl . I hi- l- done bv ] (lacing some ble glas- or porcelain vessel, immersing suitable DYNAMIC ELECTRICITY 183 the resistance offered by the liquid cell to the passage of the current. As an ordinary galvanometer or milliamperemeter will not measure an alternating current, an electrodynarnometer is used or, better still, a telephone receiver. The telephone receiver takes the place which the galvanometer would occupy in the ordinary use of the Wheat stone bridge, and indicates an exact balance, and consequently no current across the bridge when no sound is heard in the telephone. The battery should consist of only one or two voltaic cells or dry cells. A storage-cell can be used with a large fixed resistance in circuit; or the alternating electric-light current can be used by introducing an incandescent lamp and a volt controller (Fig. 146). The volt con- troller has very little resistance, the object being to yield a difference of potential of only two or three volts between the wires leading to the Wheatstone bridge. The resistance employed in the volt controller being only two or three ohms, it is necessary to supplement it by the resistance of the incandescent lamp before it is safe to turn on the 110 volts alternating current. The series lamp-socket makes it a simple matter to connect an electric lamp for use as a resistance. The socket has binding-posts and the lamp is in series with any circuit which terminates at A and B. Disconnecting the wire at A and B or both extinguishes the lamp. A 16-candle-power lamp is screwed into the socket. Fit:. 140. Vessels and electrodes for testing the conductivity of liquids: a, For liquids of great conductivity; b and c, for those more resistant. The rate of alternation in the electric-lighting current is not rapid enough to give a clear sound in the telephone receiver and consequently the electrodynamometer must be employed with this current. Xo in- duction coil is required. The 110 volts direct electric-lighting current may be used in the same way, and a series socket and volt-controller form a simple and reliable apparatus if one has not a more elaborate apparatus, such as the author's table for obtaining the galvanic, faradic, sinusoidal, and other currents from the 1 10 volts direct current. The shape of the vessel and the distance between the electrodes should vary to correspond with the conductivity of the different liquids to be tested. A U-shaped tube, Fig. 14t>, a, in which the two electrodes are separated bv a column of liquid several inches in length, is suitable for testing the conductivity of a liquid \vluch is a good conductor. The diagram h shows a vessel suitable for testing a liquid of very poor conductivity. The electrodes are fixed in position by wires which are 1M MKIHt AL KI.Kl THK ITV AND ROXTGEX HAYS sealed into irla-s tubes, the latter being partly filled with mercury. ( 'ondtict im: wires dip into the mercury and make perfect contact. The two uhi-s tubes are sohdlv fastened in the hard-rubber cover of the jar and there is another hole through the cover for the introduction of a thermometer. 'j'he ^lass-covered stem of the loAver electrode is .-hown in the diagram as pa>sing through a hole in the upper electrode. The diagram c shows still another arrangement. The two electrodes are -"lidlv fastened in a glass tube. o])en to]) and bottom, and can be immersed in a liquid contained in any sort of vessel. The induction coil for use in these measurements should have only about liiuii turns of wire and its vibrating interrupter should give a musical note representing from _'.")() to 1000 vibrations a second. There 1 iir. 1 17. \Yheatstone l>ridu<- used tn measure conductivity of a liquid. 1 be a -witch for turning the current off when not actually making st. as the current heats the liquid. The telephone receiver should i resistance of about 10 ohms. A difference of T, 1 ,-, C. in the tem- ire of the liquid makes a difference of 0.001. It may be readily hat if the measurement is to be exact down to thousandths, the inu-t be at exactly the proper temperature and must be kept there hermo-tat . e .--tn ruin rd rcxixtanccfi used in making the test include, first, a [ch should give any number of ohms from 1 to 1000 i.-tment of pi nils introducing various resistance coils into the The longer re.-istance coils should, of course, be wound in to reduce 'he disturbing effect of self induction and im, the first by having the wire doubled upon bv Chaperon's method of winding, each layer ot ind in the opposite direction from the preceding . the two other standard resistances are formed by lance wire mi either side n f an adjustable sliding . be a -traighl wire of pla'inum iridium allov or of l-copper allov. 1 meter long and about \ . i' may be a similar wire with perhaps only in . and it.- two end.- forming resistance coils. - -pace in t he mii-1 nicl ion < 'i' the appal'at US -e the measurements bv the Wheatstone DYNAMIC ELECTRICITY 185 bridge are most accurate when the t\v<> parts of the slide wire resistance are nearly equal. Figure 147 shows the arrangement of the apparatus for the measure- ment of the resistance in the cell of liquid, and Fig. 14S gives the cus- tomary diagrammatic representation of the Wheatstone bridge and indi- cates the parts which correspond to the present arrangement. Naming the different resistances DA, AC, DB, and BC, according to points between which they are placed, these are the same in both Figs. 147 and 148. According to the principle of the Wheatstone bridge, XJ/- ' V . B J ^ Saffery $ inc/i/ction coil -^ Fig. 14s. Conventional diagram of Wheatstone bridge us used to measure cone of a liquid. iuctivity no current will flow across from A to B through the telephone receiver if the different resistances boar the following relation: DA : DB : : AC : BC. The test is made by setting the sliding contact at 500, making AC and BC equal; then, while the current is turned on and the telephone held to the ear and the other ear stopped, adjusting the plugs in the resistance-box until the minimum sound is produced in the telephone. After this the sliding contact is moved along the resistance wire in one direction or the other until the absence of sound in the telephone shows that no current is passing across the bridge. Then, from the values of AC and BC in millimeters and of DA in ohms we find by the usual proportion the value of the unknown liquid resistance in ohms. The telephone forms an extremely sensitive test for the presence or absence of an interrupted or an alternating current. It shows as slight a difference as 1(I ) MU) between the potentials at the two sides of the Wheatstone bridge. It consequently affords a very exact measure of the different resistances. It does not. however, indicate the direction of the current flowing across the bridge, and consequently there is no mathematic guide to the direction in which the sliding contact should be moved. The latter is moved in one direction at a venture and the effect upon the loudness of the sound in the telephone is noted. ll 180 MEDICAL ELECTRICITY AND BONTGEN RAYS the sound becomes less, it means that the sliding contact is being moved in the riidit direction, and vice versa. The general arrangement- is exactly the same when the direct 110- volts current with a suitable volt-controller is used to excite the small induction mil. An electrodynamometer must he used instead of the telephone receiver if the slowly alternating electric-light current is used, as this does nut iiive a sat isfactorv sound in the telephone. T" recaj)itulate. A unidirectional current cannot be used in measuring the resistance of a liquid because of electrolysis and rapid polari/ation. An ordinary galvanometer or railliampcrcmctcr will not work properly with an alternating current. The telephone receiver has been found excellent for the purpose of detecting the presence of a curn nt : and the best current for the purpose is the secondary current fn>m a small induction coil of 1000 turns actuated by one or two dry cell- or by an equivalent direct primary current from any other source. The ,-ei-ondarv current from the induction coil is a rapidly alternating i ilie. One practical application of this test in medical electricity is in determining the electric conductivities of the urine and other animal fluids which vary in morbid states. Another is in the measurement of the resistance of the human body. When electrodes are applied to a cutaneous or a mucous surface, or actually puncture the tissues, to do with an electrolyte with some of the same characters as those of the liquids described in the last few pages, but even more complex. The resistance encountered by a direct continuous current, tor instance, changes very much after the current has been flowing for a time, and is greatly modified by the passage of a faradic current. A- in the case of liquids in glass jars the resistance to the flow of the current through the body is lessened in proportion to the size of the electrodes. The knowledge of the effect of varying conditions upon the resistance' ot the human body is of great importance as a guide to application of the proper current: voltage, alternating or direct char- acter, frequency, and sometimes amperage, all have to be considered. Currents and Derived Circuits. An electric current divides up atnontr two or more conducting paths in proportion to their conduc- 1 h" latter are inversely proportional to their resistances. I'' r he diair: 'am Kit:. 110 a current (' is supposed to be passing through portion of the circuit under the influence of an electro- DYNAMIC ELECTRICITY 187 Then the current C, through the undivided part of the circuit, and c' and c, through the two branches or derived circuits, are found by the following equations: = K Rr' - Rr' - r' r' 2 = E Rr' + Rr* + r' r 2 Rr' + Rr' + r' r 2 The .current C through the undivided part of the circuit is, of course, equal to the sum of the currents c' and r, into which it splits at a certain point. The' currents c' and r through the two divisions of the circuit (jr. technically, through the two derived circuits, are inversely proportional to their resistances. The current in the first derived circuit is to the current in the second as the resistance in the second is to the resistance in the first. If the resistance in the first derived circuit is twice as great as in the second, the current in the first circuit will be half as great as in the second. \AMM/V vwwwvwv Fit:. l.~>0.' Princi|)al circuit and shunt circuit. The resistance R is supposed to include the internal resistance of the battery as well as that of the rest of the undivided part of the circuit. Another case which must be alluded to is when there seems to be no undivided circuit, as in Fig. 151. The two derived circuits, it is true, do spring directly from the poles of the battery, but the current through the battery itself is an undivided one and is equal to the sum of the currents through the two derived circuits. The latter currents are inversely proportional to the resistances in the two derived circuit-. The resistance R of the undivided circuit is simply the internal resist- ance of the batterv. IBS MKIIITAL KLKCTRICITY AND ROXTGEN HAYS Fimire 1 HI .p. ISO) is diagrammatic of every case in which there are one Dimple ami two derived circuits, it being understood that the simple circuit -oinetiines includes the battery alone and sometimes the battery and an undivided portion of the circuit connected with one or with each pole. The resistance H of the simple circuit may be only the internal resistance of the battery, or if there are portions of a simple circuit connected with one or both poles of the battery, it will include t heir resistances also. Anii nunibtr <>f r/cn'm/ circuit* would be represented by a corre- Fig. !.">!. Two circuits starting from Fig. loL'. Single circuit at one pole of hat- thc liattery. tery and divided circuits at the other. sponding number of branching lines. The current through the simple circuit is eijual to the sum of the currents into which it splits in the derived circuits. The division of the current between the latter is inversely proportional to their resistances. The conductivity of any circuit is the reciprocal of its resistance. It the resistance is /-'.the conductivity is . The combined conductiv- /' iiy of several parallel conducting paths or derived circuits is the sum of the individual conductances or the sum of the reciprocals of their individual resistances. Thus, if the resistances in three derived cir- R E x mm IH Fig. 154. Loop starting and ending " point and not at tlir >ame. point of a circuit and there- fore transmit t ing no current. if combined conductance is , . . .; and if the /' /' r ! nint ,-,,,, ,/,,/;./// is tliree times as much as "lieoi these derived circuits. The joint rcsixt- ill ( 'l derivi-d cii-cuits is e( ( ual to 1 'divided b DYNAMIC ELECTRICITY IS'.) ?- (Fig. 149, p. 180), their joint conductance = ,+ .,; the , > / 2 r r / /- 77ir /om/ rcxixtonce of tiro derired circuits ?'.s equal to the product of their /vW,s7am,'f.s' dirided h// the stun of their rexixta>tcc*. When there are two derived circuits and the resistance, r, of one is known, we may calculate 1 the resistance r' required in the other derived circuit in order to produce a joint resistance, R', by the formula: The total resistance of a circuit with two derivations r' and r 2 and a resistance R in the simple circuit is = R+ , .,, or = R-<-"R'. /' /" A valuable' application of this formula is in determining the relation, between the resistance in a galvanometer and in a shunt. It seldom happens that a galvanometer is placed in a simple circuit so that all the current will pass through it. One reason for not doing this is that the galvanometer is usually so sen- sitive that any ordinary current, strong or weak, will produce the maximum de- viation and, therefore, such a current must l)o divided by 10 or 100 or 1000 to come within the working limits of its indicator. The resistance of the gal- vanometer is usually great and it would I'itr. !")."). Relation between rc- invplve a waste of power and an till- ,;,,,,. in a galvanometer and its desirable generation of heat if all the shunt. current were sent through it. A gal- vanometer, therefore, practically always forms a derived circuit, while a shunt forms another parallel derived circuit. The resistance in each is usually so calculated that the multiplying power of the shunt is either 10 or 100 or 1000: and very often these relations are adjustable, so that with weaker cm-rent s a lower, and with stronger currents a higher. multiplying power is used. The ordinary needle galvanometer undergoes deflections, which, with moderate angles, are directly proportional to the strength of the current: and, having once found the degree of sensitiveness of the instrument, it can be used as a milliamperemoter. To calculate the number of amperes indicated by one degree of deviation, divide the number of volts of electromotive force yielded by the Daniell cell by the total ohms of resistance, internal and external, in the circuit, which results in one degree of deviation. The wire in an astatic galvanometer varies in size and in the number of turns according to the currents which it is designed to measure. The usual instrument for measuring voltaic battery currents consists of about SOO turns of insulated copper wire about /. millimeter or T i- - inch in diameter. MKim'Al. Kl.KCTHH ITY AND RONTGEN KAYS Such instruments, of course, have great electric resistance, and even when .-hunted so that the joint resistance of the galvanometer and -hunt i- only one-tenth or one-hundredth that offered by the galvan- ometer when un-hunted: this joint resistance is still so large that it must be accurately known and taken into account in all the above measure- ment-. Thi- re-i-tance may be obtained from the table on p. 219 if the diameter and the length of the wires in the galvanometer and the are known. A needle galvanometer is rendered ballistic or is damped by the addition of brass to the needle. This, by its weight, causes the needle i|uickly to assume a position of rest instead of oscillating back and like a pendulum before finally coming to rest in the position in influence of the current tends to place it. A needle galvan- ter n i.-t always be held in a horizontal position. An\ in edle galvanometer in which the needle is of large size, perhaps ng as rlu- diameter of the coil, and in wliich the coils of wire are : parallel with the meridian and hence with the needle before an ctirrenl i- turned on, will undergo deviations in which, within < ' in limits, the si ivngth of the current is pro port ional to the number 1 hompson's Lord Ravleigh's) mirror galvanometer is used to mi a.-uiv I he smallest currents, as in testing the insulation of submarine cables and in observations upon animal and vegetable electrical currents. I' has a large coil of many thousand turns of the finest copper wire, and a magnetic needle \vliich is a piece of the hair-spring of a watch, about ; inch in length. This carries a very small mirror and is sup- : .' side the coil bv a fine silk thread. A rav of light is reflected tid shows as a \\hite spot <>n a graduated scale '.) \\ liLri;t .-pot i- at the /.ei'o mark the instrument currents, \\iihin the ordinary limits of the scale ihe cnrreni is directly pi-o])ort ional to the amount of : : each subdivision on the scale is found in the ilue of cadi degree in the ordinary needle galvan- Tan^ent Galvanometers. These are galvanometers in which the ' i- proportional not to the number of degrees of MI tin l angeni of t he angle of deviat ion. A ! ''.'.. 1 ")< ". i this difference deal 1 . a line i Irawn t com < me em 1 ' a tangent in t he curve i. < .. at a right out intied until it Mit ersecl s the ' e other -ide of the angle. DYNAMIC ELECTRICITY 1 ( .)1 No current could be strong enough to produce a deviation of <)() degrees. A tangent galvanometer is used for measuring currents of low potential, but considerable quantity. It consists of a vertical copper ring which is placed parallel with the magnetic needle and which is to transmit the current, and surrounds a magnetic needle with a graduated circle beneath it. It is usually graduated in degrees and the tangents have to be looked up in a table; but it would be practicable to have tin 1 tangent values marked upon the scale. To give correct values the needle in a tangent galvanometer should not be more than one-twelfth or one-tenth as long as the diameter of the copper ring. The Sine Galvanometer. This is a needle galvanometer by which the. strength of the current is indicated by the sine of the angle of deviation instead of by the number of degrees of circular measure. The sine of an angle or of an arc of a circle is the line drawn from one end of the arc perpendicularly to the radius which terminates in the other end of the arc. In Fig. 157, a---d is the xine of the angle b or of the arc a-c. In a sine galvanometer there is the usual magnetic needle moving over a horizontal circle graduated in degrees 360 degrees in all. This circle and the magnetic needle are fastened at the center of a vertical ring around which are several turns of heavy, insulated cop- per wire, through which the current is to be passed. The whole is supported on the vertical axis of a horizontal circle, forming its base and around which it can be turned. In measuring an electric current the vertical coil of wire is first placed in the plane of the meridian, and, therefore, parallel with the magnetic needle, the current is then turned on and the vertical coil is turned to a position parallel with the mag- netic needle. The needle is now at a certain angle from the north and south direction under the influence of a current which in this new posi- tion exerts its force at an exact right angle to the direction of the mag- netic needle. The strength of the current under these conditions is proportional to the xine of the angle of deviation. The sine galvan- ometer is suitable for very heavy currents. The tangent and sine galvanometers both give readings which uive directly only the comparative strength of different currents. To obtain absolute values in amperes or milliamperes it is necessary to ascertain the degree of sensitiveness of each instrument by experiment with an electric current, just as in the case of the ordinary galvanometer. The Limits of Accuracy of Galvanometers. The current strength as indicated by a tangent galvanometer i> more exactly proportional to the tangent of the angle of deviation when that angle is about -\~) degrees than when the angle is either much larger or much smaller. \\ith all galvanometers the more nearly an angle of (10 degree.- is approached, the less relation there is between the current strength required to produce 1 that degree of deflection and anv geometric func- tion of the angle produced. In such a case either to measure the current or test the sensitiveness of the galvanometer it will be necessan to use a source of low potential or to shunt the galvanometer, so that only a small fraction of the current will pass through it. Any galvanometer can be tested as to its degree of sensitiveness b\ placing it in t he same circuit with a .-tandard galvanometer and bat tery. Amperemeters or Ammeters and Milliamperemeters or Mill- ammeters. These are galvanometers \\hich are irraduated by the manufacturer in amperes or milliamperes, instead of degrees. Thev 192 MKr.l'-.U. KI.KeTKHTFY AND ROXTGEX HAY'S are usually -hunted, and the 1 graduations on the scale indicate the te)tal current through the galvanometer and its shunt. The milliampereme- ters -oM for electrotherapy frequently have 1 two or more shunts of different resistance, and in this case there is a switch by which one e>r the other caii be introduced. Numbers to which the handle of the -witch point-; indicate the number by which the 1 dial number must be multiplied to L r ive the combined current through the 1 milliamperemeter and -hunt. Thus, in one position of the switch the numbered divisions on the dial may indicate milliamperes and the ten subdivisions of each repre.-ent tenth- of a miiliampere. The milliamperemeter may then measure currents from ,',, to "> milliamperes. In another position of the -witch indicated by " 10") the numbers on the dial are to be mult iplii d bv l en, and each numbered division represents 10 milliamperes while the ten subdivisions of each of these indicate 1 milliamperes. The ineteT mav then register from one to fifty milliamperes. In another po-iti"ii of the -witch (indicated by "X 100") the figures on the dial are to be multiplied by 100: each numbered division indicates 100 milliamperes and each of the smaller subdivisions indicates 10 milli- ampeivs. The currents measured vary from 10 to o()() milliamperes. nother position of the switch (markeel "out") inelicates that the current does not pass through the 1 milliamperemeter at all. This is for use in experimenting (not upon a patient, but upon some 1 other conductor) with currents of unknown strength, and which might damage the milliamperemeter. The 1 arrangement of multiplying powers described above 1 is the one adopted by the author for the milli- amperemeter which measures all the different currents applied to the patient from the voltaic, faradic, tie 1 Watteville 1 , ami sinusoidal apparatus. It should be stated, however, that the galvanometer referred to is not of the magnetic ne-eelle type, but etf the 1 movable 1 coil or d'. \rsonval type. The d'Arsonval Movable Coil Galvanometer (Figs. loS and loO). This instrument consists of a powerful permanent magnet and a :reely suspended coil of fine wire, through which the 1 electric cunvnt measured passes. The directive 1 force 1 is of the same nature 1 as in the> rase of the magnetic needle L r :dvanometer; it tends to place tin 1 tnatrnet and the coil at ritrht anirle- to each other, and does so in thi- i-a-e by moving the coil. The two poles of the magnet are concave 1 DYNAMIC' KLKCTKICITY 193 atul close together, and enclose 1 ;i cylindric space in which the coil is pivoted so as to he free to move in either direction, hut aKvavs in I lie plane of the horseshoe magnet. The meter may he placed in anv position, and this makes it very much more convenient than the mag- netic needle galvanometer. The movable coil is made of many turns of fine insulated wire 1 wrapped around a metallic framework and con- tains a soft-iron core. The directive influence becomes manifest the moment the current begins to traverse the turns of wire in the coil and it tends to place the coil at a right angle to the direction of the lines of force in the magnetic field. This motion is opposed by the traction of the two spiral springs of zinc wire which, when no current is passing, keep the coil exactly parallel with the magnet, and the indicator needle carried by the coil exactly at the zero mark. An improvement over the two spiral traction springs consists in a single spring, like the hair-spring of a watch, coiled in a flat spiral. The spring is so adjusted that when it is not subjected to any outside influ- ence it holds the coil and indicator exactly at the zero mark. It exerts a gradually increasing pressure as the coil deviates in one direction or the other under the influence of the electric current. The moment the current ceases to flow, the spring brings the indicator back to the zero mark. The direction in winch the coil turns depends upon the direction of the current, and the connection of the milliamperemeter with the battery must, of course, be such that a deviation toward the -f mark will occur with a positive current., and vice versa. The scale- may begin with the zero mark at the extreme left hand, and in this case the connections must be right in order to get any reading at all. If the connections are wrong and the milliamperemeter, therefore, is reading backward, the simplest plan is to unfasten the two wires, one leading to it from the battery and one leading from the milliampere- meter to the patient or apparatus, and change their connections. The directive influence is almost entirely that of the permanent magnet, and the movable coil is relatively very little affected by the earth's magnetism. This is the reason that a d'Arsonval milli- amperemeter works equally well in any position. The angle of deflection is not easy to accurately calculate and the in- strument is usually graduated by comparison with a standard one in the same 1 circuit. "With a milliamperemeter registering from to o milliamperes, the space on the? scale between and 1 is 1| times as long- as the space between 4 and o. The currents induced in the metal framework upon which the coil is wound tend to make the d'Arsonval milliamperemeter "dead-beat"' or to cause the indicator to promptly come to rest at the angle of deflection corresponding to the strength of the current. The d'Arsonval amperemeter is the same instrument, but designed to measure heavier currents, its divisions indicating amperes instead of milliamperes. The usefulness of the different shunts in varying the multiplying power is the same as with the magnetic needle galvanometer. The voltmeter is simply a galvanometer with a very great resistance and graduated in volts required to produce the different deviation-. It is connected directly with the two terminals of the generator and not at all with the patient or apparatus supplied with current. The Electrodynamometer. This is an instrument for measuring 13 1U4 MKDICAL KLKCTHHMTY AND RONTGEN KAYS electric currents l>y the repulsion that exists between currents of elec- tricity passing in an opposite direction through two parallel wires or parallel parts of the same wire. The form in- vented l>y Siemens consists of a vertical coil of heavy insulated wire IT, and a single U-shaped piece of wire /'', suspended over this by a spiral spring with a knob, x, at the top. by which the wire loop can be turned in either direction later- ally. And this knob turns an indicator z over a graduated scale N. The wire ic' also carries an indicator ,:' , which passes over the scale N. The current enters the coil at a binding-post, K, and leaves the coil where 4 the other end of the wire dips into a vessel of mercury. It then enters the single loop ir' , and leaves that at another vessel of mercury, from which again it passes by a short wire to another k binding-post where it leaves the meter. The adjustment of the different parts is such that when no current is passing, both indicators point to the zero mark on 1 he scale. When the current is turned on. the suspended loop ir' is repelled and tends to be rotated and the knob x is to be turned sufficiently to make the action of the spiral spring keep the single loop w' in its original posi- tion and its indicator ?J at zero. The extent to which the knob xmust be turned is proportional to the square of the current strength. The scale may be marked in amperes after its degree of sensitiveness has been tested by the manufac- turers; or it may be marked in degrees of a cir- cle, and each reading will then require a calcula- tion based upon the strength of current which has been found to be indicated by a deviation of one degree. The elect rodynamometer is in- rement of heavy currents used in electric light- able in almost everv wav than the d'Arsonval 1 Hi- MEASUREMENT OF ELECTROMOTIVE FORCE Quadrant Electrometer.- The electromotive force of a single cell, -ry, or of :i iienerator of any kind may be found by means of a ich i- an instrument dependent upon the f two charged bodies: attraction when the ivpuUioii when they are similar. A metallic -erlioiis by two diameters at right angles to each tioii- are fa-tened on in-ulated glass supports so i 1 -aine plane, l>ut are -lightly separated from each Irani i- connected \\ith i he one directly opposite by t!,-it aluminum needle i- suspended over these 1 1 wire from I he inner coat of an in vert e be* measured. The resistance is now varied until the 1 milli- ampeMvnieter shows an equal deflection, and hence 1 the 1 same 1 cunvnt as in the 1 first observation. The- electromotive fe>rce is directly propor- tional to the resistance when the 1 currents are equal. The Potentiometer. This is an arrangement of apparatus for measuring the 1 difference in potential between any twe) points, such as the 1 pole's of a battery, and acts equally we'll whether the 1 battery is on open or cle)se i d ciiruit. It consists of resistance's, a standard cell, and a galvanometer, and its principle' is the balane'ing of the 1 electromotive force of the one 1 against that of the 1 other in sue-h a way that no e'urrent flows through the galvanometer. Figure 1 19(i shows the arrangement diagrammaticallv. The' wire 1 a-b has a unifeirm thickness and considerable resistance', and the resistance of any two portions of it is pmportional to their length measured upon a me'tal scale over which it is stivtche'd. At its two end- this wire is connected by a wire of very small resistance with a constant batte'ry, such as a single storagv-cell .1. The differene'e in potential betwee'ii the' two ends of this wire will be' about 2 volts: r is the cell which is to be te'sted. and it must have 1 an electromotive force less than that of the battery .1. The positive 1 pole of c U connertcu to lidmg contact. The elect roinotive forci !vp:v>eiited tu the ilitTerence in potential between '/ and .r. and L: :o produce :; current through r whose ii ea ured is subst ii uted fur i he standard the mi iliampere- ( '-' i- noted. The electromotive DYNAMIC ELECTRICITY 107 force of the two generate>rs is directly proportional to the currents in niilliamperes; and F- F' ,/ A slight correction mav have to be' made for the internal resistances of the two batteries, but this is not necessary if the external resistance (in the resistance box and galvanometer) is comparatively large. Lumsden's Method. The standard cell F/ and the generator F L> whose 1 electromotive force is to be measured are placed at some distance apart, and are connected with each other so as to torm a normal series. The zinc of the first is connected with the 1 copper of the second, and again 1 he zinc of 1 he second wit h t he copper of t he first . A (M'oss line passes from t lit 1 middle of one connecting win 1 to t he middle of the other, and any current in this cross wire passes through a galvanometer. One of the 1 main conducting paths (Fig. 1(>2) is a simple 1 wire 1 of ample proportions \vhose resistance is so slight that it eloes not have to be consielered. Resistances are placed in the 1 other conducting path be 1 - tween the 1 twe> batteries. One of them, R', is between the standard battery and the point where the cross wire 1 leaves the 1 main wire. This has a fixed standard resistance so large 1 in comparison with the 1 in- ternal resistances of the batteries that the latter may be 1 disregarded. The 1 ot IKT resistance 1 . R-, between the generator whose 1 electromotive force is to be measured and the 1 attachment of the cross win 1 is obtained from a resistance 1 box by means of which any requireel resistance, large 1 or small, may be eMiiploye'd. The resistance 1 R- is varied until the gal- vanometer, (I. indicates that no current passes through the 1 cross wire A-B. The 1 electromotive force 1 of the generator E- is the'ii E- == E' ^ ,. The d'Arsonval Voltmeter. The voltmeter, on the' principle of the' d'Arsonval galvanometer, is made in different sizes and shapes. One is like 1 a watch and has two terminals, one be-ing a point which may be 1 pressed upon one pole of the battery ami the other an insulated wire leading to the either pede 1 of the battery. One' of this size and shape is very convenient for use 1 in testing voltaic batteries. Eae-h different cell may be tested in this way without disconnecting it at all from the rest of the battery. In some batteries there is a switch-board upon which are metal contact- which lead to the poles of the different cells, and it is simply nece-sary to touch these two contae-ts without opening the' battery case at all. Still other batteries are more elaborately provided, and have 1 double cell -electors by which the two poles of any individual cell, as well as of several cells, may be connected wit h a Mat ionary milliamperemeter. In thi- case' the cell selector is applied to the two contacts from the same cell: the terminal- of the voltmeter are applied to the terminal binding-posts/ of the switch-board and the 1 current is turned on. Fach 19S MEDICAL ELECTRICITY AM) RONTGEN RAYS separate cell may he tested in this way or any nuinher of the cells at once. When a voltmeter is used to test a voltaic cell OH open circuit, it means that the current is not allowed to pass in any other way. The pules of the cell may he disconnected from anything else, or if con- ducting cords are attached to the two poles, the other ends of the cords d,> not coine together directly or through any other conductor. A battery of cells may be tested in the same way. The circuit is open until the voltmeter is applied to the positive pole of the cell at one end of the series, and the negative pole of the cell at the other end of the he voltmeter is in essence a galvanometer, and its deflection up"ii the strength of the current passing through it. As the a known resistance, the electromotive force can be cal- . It is customary, however, to mark- h indicate* the different voltages, and d by the manufacturer by comparison e absolute standard of electromotive force i- obtained from a standard voltaic cell such as Clark's, which is l.l.'il volts. Another method of graduating a voltmeter is by using a galvanometer in circuit with the voltmeter. The resistance of both in-trumeiits must be found either by test or by calculation (the resist- ance of so many feet of copper wire of such a size). If the galvanometer shows that a current of 10 amperes is flowing and the resistance is known to be 1 1 ohms, then there is a tension of 110 volts, and the place on the dial of the voltmeter to which the needle has deviated would be marked IK) volts. The resistance of a voltmeter is usually a very large one compared with that of the normal circuit, so that the current is often but a fraction of the battery current when in actual use. Whether this resistance is all in the coils of the voltmeter, or whether it is partly in a -hunt, depends upon the magnitude of the currents it is designed to measure. Voltmeters about as large as a watch are designed to measure bat- teries with electromotive forces up to three volts, and yielding currents up to about MO amperes. They have subdivisions as fine as I- volt, and are -nil able tor te-i ing t he electromotive force of single 1 cells of any kind, especially wel or dry voltaic cells or storage-battery cells. The latter .-hould be recharged before they have become entirely exhausted. To allow them in remain in use until the electromotive force falls to zero -erioii-|y impair- i heir elliciency. high resistance in the d'Arsonval voltmeter, a great many times il itself, makes it give suliicient ly accurate results without tor taking the internal resistance of the cell into account ry exceptional cases, where extraordinary exactness is est the potential of a storage battery in operation t. The elect romot ive force mav prove to be about open circuit , and .-till may fall very decidedly when and the current r- parsing through the motor or indication that it i- high time that the cell or d. g the DYNAMIC ELECTRICITY 100 ing currents up to 20 amperes, are about 4| inches in diameter and pro- portionately thick and heavy. They look just like amperemeters, and have binding-posts to which wires from the poles of the generator are to be securely screwed. It is perfectly practicable in any case to measure the electromotive force of a battery while in actual operation, and it is often very impor- tant to do so. The fact that the voltmeter has a very high relative re- sistance makes it transmit only an inconsiderable fraction of the current when it short circuits the entire apparatus by being placed directly be- tween the terminals or the two poles of the battery. It is not in series with the patient or apparatus supplied with electric current. The needle really deviates according to the strength of the current or the number of amperes passing through the uniform resistance of the large number of turns of wire in the voltmeter, and, according to Ohm's law, the number of amperes must be directly proportional to the number of volts when the resistance is uniform. If the voltage is uniform, as in the case 1 of the 110-volt electric-lighting current, there is no need to have a voltmeter; an amperemeter is required to show the strength of the current, and indirectly the resistance in the circuit. If the voltage and the resistance are both uniform and are known, neither voltmeter nor amperemeter is required; the current strength is uniform, and can be calculated from the other two factors. If the voltage is variable, but the resistance uniform, a single instrument, the regular amperemeter, will act also as a voltmeter. Two sets of figures would appear upon the dial, the outer set indicating volts and the inner set amperes. Such a meter would give a correct reading in amperes in any circuit, but its reading in volts would be correct only in a circuit having exactly the same resistance as the one for which it was originally tested and grad- uated. A separate voltmeter having in itself a large resistance may be placed between the terminals leading to any circuit, and will give correct readings. It is almost indispensable when the current is derived from a variable source of electromotive force, and when the resistance in the circuit is also variable. Law's Method of Condenser Discharges. The amount of elec- tricity with which a condenser of a certain capacity can be charged varies directly with the electromotive power. Figure 163 shows the gen- eral arrangement of the apparatus for making this test. C is a condenser of a capacity of - microfarad (or a larger one, up to 1 microfarad, may be used). G is a galvanometer whose resistance is G ohms. S is a shunt past the galvanometer provided with a sliding contact by means of which the shunt may be disconnected entirety or it may offer a resistance varying from a small to a very large amount. The resistance in the shunt is S ohms. E is the battery and K the key by which the circuit is closed or opened. Two observations are required. In the first a smaller battery F/ (volts) is used, and the galvanometer is not shunted. On pressing the key the condenser quickly becomes charged, and on releasing the key the condenser immediately becomes discharged. The latter effect produces a momentary current and a readable deflec- tion of the galvanometer. In the second observation the larger battery E" (volts) is used, and the resistance of the shunt S is varied until the condenser discharge produces the same deflection of the galvanometer as in the first observation. The resistance then employed in the shunt G + S " may be designated as S" (ohms). Then, E ' , JIM) MKDIC.VI. KI.KCTKldTY AM) KONTCKN HAYS It the weaker t;vnerator is a staiulard cell with a known electromo- tive force, a nil 1 he joint resistance in t he galvanometer and its shunt is so large that the internal resistances of either battery need not be taken into account, thru the electromotive force of the stronger battery is equal to that of the smaller bat tery mult iplied by the multiplying power ol t he shunt etiipi' ivei 1. 1: the electromotive force to In 1 tested is smaller than that of the lard cell, the unknown electromotive force would be tested first M -huntim: the galvanometer. ,\nd then the standard cell would U -ubst it uted and so shunted as to produce the same deflection. The ;:.'. !;o\vn electromotive force would then be found by yed wit h t he hit ter. I:' K proves necessary or desirable to use a shunt with each of the two L:< iterators, thm the electromotive 1 forces of the two generators are directly proportional to the multiplying powers of the individual shunts u-ed wit h i hem. The diagram Fig. Kio* shows these variable shunts only in a sche- matic way. In reality a resistance box would be used to furnish the wide ratine of resistances required for these measurements. The well-known property which a condenser possesses of storing up large quantities of electricity renders it possible by this method accu- rately to measure electromotive forces so small that a continuous current hn itigli i he same sensitive galvanometer would not produce a measure- leflectioi). I hf watt i- a unit of electric power and is the power exerted by a current of ! ampere with a pressure of 1 volt. A \\ kilowatt transformer l< onojictuated by a current of -1500 watts, and this may mean 100 volts :i: "l ;' amp'-res; or any numbers the product of which will be 4500. Hie wattmeter i- de-igned to measure the power consumed in any apparatus through \vhich an electric current, especially an alternating - pa-sing. In the case ol' a direct and uninterrupted current 1 constant voltage and amperau'e passing throuu'h an "'. ' < "" u " n ;l '"l ''onstani resistance, no separate wattmeter is I li" inmiber of volts multiplied by the number of amperes ' ' "t \vatts. P.ut with an alternatin- current oi' with a 'h is interrupted, as by a \\'ehnelt interrupter, in " i- difficult to say diirin.ti: just what part of each period - :t: "l \voi'k i- bem- perform,. d. a wattmeter serves ti ni'-a-ure 1 1 wattmeter is similar to that of the elect ro- dy tiamoini't er p. p. :; i DYNAMIC ELECTRICITY 201 paths, in one of which different carefully tested resistances are intro- duced, and in the other is introduced the resistance which is to be meas- ured. The word bridge has reference to the position of the galvanometer in relation with these two circuits. The galvanometer is inserted in a line which bridges across between the two circuits, and a current flows through it from the circuit in which there is the greatest tension. We- might use the face of a clock as a diagram to illustrate the principle of the Wheatstone bridge. Twelve o'clock would indicate the point at which the positive wire from the battery is connected with the wire cir- cuit, and o'clock the connection with the negative wire. The current passes between these points along two different paths: down along the right-hand margin and down the left-hand margin of the dial. At the center of the clock face is the galvanometer, whose wires pass from the 3 to the 9 o'clock mark. When the conditions arc 1 the same at these 1 two marks, no current passes through the' galvanometer, but when there 1 is a stronger current in consequence of a greater potential at 3 than at 9, the 1 galvanometer will show that a cm-rent is passing through it from the 3 to the 1 9 o'clock mark. The resistance to be measured is introduced at 1 o'clock, and the different standard resistances are introduced at 11 o'clock. The latter resistances are increased or diminished until they are equal to the resistance to be measured, just as standard weights are used to weigh an object. Equality between the two resistances is indicated when no current passes through the 1 galvanometer. REGULATION OF ELECTRIC CURRENTS Rheostat. The 1 regulation of the 1 current from a voltaic battery for therapeutic application may of tern be accomplished by selecting the 1 proper number and arrange'ine>nt of cells employed, but a rheostat or adjustable resistance is an invaluable addition. It is often necessary to use heavy currents which are free from any discomfort when turne'd on and off very gradually, but which produce 1 disagreeable shocks if suddenly increased or diminished. A suitable rheostat enables one to change the 1 strength of the current more 1 gradually than any cell selector. The employment of the 1 poweTi'ul and sometimes even dangerous current from a dynamo ivquhv-s the use of a rheostat or of a volt controller to reduce t lie amperage or the voltage' of the current before it can be applied to the human body at all. Her the' rheostat is used not only to turn the current on and off gradually, but also to limit the amount which can reach the patient. There is no convenient me>ans of regulating the power of the dynamo to the requirements of e'ach therapeutic application, and so different instruments are employed to modify the current before 1 it reaches the patient. The pri-nc i]>le nf the r}n o*ti i/nnl rcxixtances trliich are easily varied may be obtained by drawing several parallel lines with India ink upon strong drawing paper. The-e are close together, but of decreasing length. A metal clamp ' o uc lie- all 1 he line- at one end, and a metal contact may touch from one i" all "I these line- according to where it is applied. Resistances varying from n.nl to 20.000. meg-ohms are obtained in this way. The current transmitted varies from 0.1 ma. downward. 1 I he volt controller or reducer of potential depends on an entirely ga uniform resistance throughout , along t he line. 1 f t lie dii'fer- is a cert am i'ract ion oi t he inc. the difference in pre DYNAMIC ELECTRICITY 203 connected with one polo of the dynamo and a point half-way along the external resistance would register a tension of 55 volts. An apparatus connected with these two points would receive a current the strength of which would be found by dividing 55 volts by the resistance of the apparatus in accordance with Ohm's law. The same 55 volts potential can l>e obtained by making the connection with two points anywhere along the main line, providing that half the resistance in the main line; is included between these two points. Any fraction of the original 110 volts may be obtained by connecting the apparatus at points along the main line which include between them the required fraction of the resistance in the main line. The volt controller is an apparatus for regulating the voltage supplied to a medical apparatus by connecting it with points along the main line between which a variable portion of the resistance in the main line may be included. The resistance in the main line consists chiefly of a resistance coil in the volt controller itself and the contacts are made by moving a contact spring along over the different turns of wire. If both terminals of the medical apparatus are in contact with the same turn of wire in the volt controller, there will be no difference in potential, the voltage in the therapeutic apparatus will be zero, and no current will How through it. Moving the contact to different points so as to embrace more and more of the resistance in the main line, the potential supplied 1o the medical apparatus may be varied from 1 up to 1 10 volts (Fig. lti-1 1. A shunt circuit has many important applications in electrothera- peutics besides that of a volt controller. It is a conducting circuit joining t wo points in a conductor t hrougli which a portion of t lie current inav pass. The intensity or amperage of the current through the two conducting paths is in inverse proportion to the resistances in the two. It one has a hundred times the resistance ot the other, only one oiie- hundredth part as much current will puss through it as through the other parallel path, with less resistance. The tension or voltage at the 201 MKDICA1. KI.KCTHIC1TY AND ROXTGEN KAYS two points of junction i- the same for both circuits, and the strength of the current in each is absolutely regulated by the resistance. Another important application of the shunt is in connection with the Lialvanometer or amperemeter. The heavy currents used for .r-ray coils would quickly heat up and destroy the fine wire in a galvanometer, and, lie-ides the injury to the meter, its resistance would occasion a irreat waste of power. And then, again, the directive 1 influence of such a powerful current passing through the many turns of an amperemeter would be entirely too great for practical purposes. The maximum deviation would be produced by the weakest current ever employed for Mich purposes, and one could not read on the meter the different additional strengths of current. In fact, an instrument of this kind is .-o delicate in construction and so sensitive to the directive influence of the current that it is fitted to transmit milliamperes or thousandths of an ampere rather than whole amperes. To fit it for the measure- ment of currents varying from 1 to 50 amperes, the amperemeter is placed in shunt. A metal strip passes directly from one binding-post of the amperemeter to the other, and a very large portion of the current passes through this, while a very small portion passes through the winding of the amperemeter. The exact fractions of the current passing by these two different paths between the positive and negative binding- posts are determined by the very small amount of resistance in the metal strip and the very large amount of resistance in the many turns of tine wire in the winding of the galvanometer. Another type of amperemeter for heavy currents has only a very few turns, or possibly a single turn, or even a straight bar in relation \\ it h a movable magnetic needle. It is for currents of such great amper- age that it is not necessary to multiply their directive influence, as in the ordinary galvanometer. These are not, however, the currents , i\vd in elect ro therapeutics, but t hose employed in the t ransnnssii >n iwer, hundreds or even thousands of horse-power. ti//are hind-posts to see whether there is any current. It will arc across a considerable fraction of an inch at the break, and if it is turned on and off by a kev. this should have a spring producing a quick break. This is to prevent the for- mation of an arc, which would occur if the two contact surfaces were slowly separated. An arc would melt and ruin the contact surface.-. The 110-volt direct current will not spontaneously leap across a space nf even an eighth of an inch, and anv siood insulation, such as a laver 201) MKDIfAI. KLECTRK'ITY AND KONTCKN RAYS of nutta-percha an eighth of an inch thick, covered by a braided fabric of silk or cotton, will prevent the current from escaping from one win' to tin 1 other, even if the covered wires are twisted together. This is often done for convenience, so as to be handled like a single cord, and even >inirle cords of gutta-percha about half an inch in diameter are made, iiu'lo-nm- both wires. The fact that such an insulation must eventually become cracked and porous in spots does not mean that the current will neces-arily leap across at such a point. Kven a porous covering will >uilice as lonsj; as the two wires are held at an appreciable distance from each other, and no good conductor extends from one to the other. Thi- current may be short-circuited by cutting a charged double conducting cord with a penknife. Both insulating layers are cut through, and the steel coming in contact with both wires allows the full force of the current to pass through the very small resistance of the knife-blade. The result is startling, and may be disastrous. An excessively .-iron ii current passes across this small space, and tremen- d ms heal is gem-rated, burning a piece out of the knife-blade, not meivh fusing, but vapormng. the steel. The wires at this point are destroyed in the same way. and the safely fuses all along the line are burned out. Tin.- brings t he flo\\- of electricity to an end. and saves 1 he ho ise from beii in set on tire. The wires throughout the house would gel so 'in the passage of a short-circuited 1 10- volt current that in a few minutes thev would set lire to i he woodwork. 'I he same undesirable experiment may be made by holding a knife or a key against anv exposed parts of the two wires, or the metal parts of a motor, or a switch, or the terminals oi a coil. '1 he same thing mav happen from one of t he wires becoming loosened in some way. and its bare end coming in contact with the hare end of the other wire, or with some metallic part of the apparatu.- connected wiih the other wire. About almost every electric apparatus to be run by the 1 MJ-volt current there are portions exposed tin possibility of short-circuit. Such portions, switches especially. ie separated from any inflammable structure by a marble or slate base. I )o not bring any metallic object near any exposed part ''' u'ire or apparatu-. and in making the necessary adjustment of itches niid rheostats touch only the insulated handle provided for that purpo-e. In >he case of a dynamo, the electromotive force is usually so great in proportion to the internal resistance that very often the only electro- motive force to lie considered i.- the voltage at the two terminals of the dynamo, and t he only resistance to be considered is that in the external circuit . \ ' . : this voltage will pass across a considerable space if the and there i- so little resistance in the circuit as 1 , laruv number of amperes, and the contact is i-ij. I In- i- the pvin ipon \vhich an electric arc is . . 1. The -ame voltage is ;."' ;ipi to cross even a small space 'hi ':.: i- iade, and a ver\ -buhl impi 'ft'ect ion in i he con t act ii r rent from pa mil. I'here a re t wo reasons. 1 here- \vire- soldered together at every permanent joint V ii mpleie connection mi^ht either prevent _ >: i he \viivs mi< luring t he ll< >w of ilnim an- -et fire to rk or iras. i isinii t In I HI-VI ill diced current should DYNAMIC ELECTRICITY 207 comply with the regulations of the U. S. National Board of Fire Under- writers in order to be safe from risk of fire, and it then does not add anything to the cost of fire insurance. In many places it is a criminal offense to turn on the current at all until the wiring has been inspected and found to comply with these regulations. A pair of Xo. 14 copper wires are suitable for one to eight incandescent lamps. An .r-ray apparatus should always have its own pair of wires leading from the mains, and not tapped for lamps or any other apparatus. They should he a pair of Xo. 10 wires. This is also the proper size 1 for the powerful arc-lights employed for phototherapy. Electric-light and Power Service. The commercial arrangement for generating direct current for electric-light and power service in cities is usually as follows: Two 1 10-volt dynamos are connected in series; this gives a three-wire distribution service. The middle wire is called the neutral one. If the house is to be supplied with 110 volts, then the three wires are brought into the basement and connected with the meter. In order to obtain a 110- volt current, connections are made with the neutral and one outside wire. If a 220-volt current is desired, then connections are made with two outside wires. The size of the distributing wires is regulated by the rule of the Fire Underwriters. In having a place wired, it is always well to have the contractor use a size or two larger than the Fire Underwriters' rules call for, so that in case more 1 current is desired, it can be safely taken from the original installation. The extra cost does not amount to much. In having electric service put in, it is always well to see that the cut-out blocks and fuses are put in a convenient place, so that in case of an accident a fuse can be easily replaced. As a rule, contractors do not figure on putting in a main switch, but it is advisable to have this done, and also to have 1 it. placed in circuit before the current enters the meter. The particular advantage of this is that in case you go away for any length of time, the current is absolutely shut off from the meter and the rest of the house. As long as the meter is connected with the service, it is consuming a small amount of current : this usually amounts to about 30 to -40 cents a month. Another advantage of the switch is that if you wish to make any changes, you can open this main line switch, being absolutely certain of not being injured by an accidental short -circuit. A "flush receptacle" should be used for a Cooper Hewitt lam]) or for a negative examining box with several incandescent lamps. A fused knife switch on a slate base is the proper tiling for the .r-ray connection or for a large arc-lamp. The ordinal'}' key receptacle tor a single incandescent lamp may be used for small motors and for cabinets for voltaic and faradic treatment, for diagnostic illumination, and for cauterv. JOS MKDICAL KLKCTIUCITY AND UOXTCiKX HAYS ( >i i -ii>i: \\ < U;K. Sf[-\ ice \\ ire- inii-i !i:!\ i- :ni M| i|>n>\'c(l nil 'her insulating covering. Line wires ..r\;c.'-. i!.;-.: li:i\. an approved \\ ea 1 1 uT-j in >< >f or rubber insulating L: Ml tit- \\iiv- ruii>l have :m in-ulation equal to ihat of the conductors \ \1 ,~- lie -ii placed thai moist un- cannot form a cross connection between I ,-in. iini h foot apart, and not in contact with any substance other than their linu .: >rt> \Yood'-n Mock- to whicli insulator- are attached must : . ; vi r 1 1 i ii i 'in ire -urtace \\ it h at least t wo coats ot waterproof paint. MM-' lie -o -plicrd or joined as to be both mechanically and electrically mil -older The joints must then be soldered, to insure preservation, covered wit Ii an in-ulat ion equal to t hat on t he conductors. All joint- mu-t be -oldered. even if made with some form of patent splicing device. Thi- ruling applie- to joints and splices in all classes of wirini: covered by these rule- I\>II>F. VYoHK. \Vires Mu-; not be of smaller si/e than Xo. 14 H. A: S. guagc, except as allowed under No>. _' t v and \~> b. Tie \\iiv- mu-t have an insulation equal to that of the conductors they confine. Mu-t be so -pliced or joined as to be both mechanically and electrically secure without -older. The joints must then be soldi-red to insure preservation and covered wit h an in-ulat ion equal to t hat on the conductors. Stranded wire.- mu-t be soldered before being fastened under clamps or binding -crews, and whether stranded or .-olid, when they have a conductivity greater than that of \o. ,s 11 A. S. guage. they mu.-t be soldered into lugs for all terminal con- Ileet ;, ills. ()(). (/>) Must lie ot rubber or other approved substance, mid of a thickness not less than that given in the following table: P>. it S. (lauge Thir-kness. IS to Hi .', inch. lf> to S > r ' 7 to _> ;v, 1 to ()()()() Measurements of insulatinir wall are to lie made at the thinnest portion of the dielectric. !r) The completed covering must show an insulation resistance of at least 100 megohms per mile during thirty days' immersion in water at 70 I-'. 1 ('/> Kach foot of the completed covering must show a dielectric strength suffi- cient to resist, throughout live minutes, the application of an electromotive force of .':!()( )0 volts p(>r i; ' f inch thickness of insulation under the following conditions: The source of alternating electromotive force shall be a transformer of at least one kilowatt capacity. The application of the electromotive force shall first be made at 1000 volts for five minutes, and then the voltage increased by steps of not over .'JOOO volts, each held for five minutes, until the rupture of the insulation occurs. The tests for dielectric strength shall be made on a sample of wire which has been immersed in water for seventy-two hours. One foot of the wire >mder test is to be submerged in a conducting liquid in a metal trough, one of the transformer ter- minals being connected to the copper of the wire and the other to the metal of the trough. PROTECTING BKAID. (Jt) All the above insulations must be protected by a substantial braided cover- ing, properly saturated with a preservative compound. This covering must be sufficiently strong to withstand all the abrasion likely to be met with in practice, and sufficiently elastic to permit all wires smaller than Xo. 7 I>. iV S. gage to be bent around a cylinder with twice the diameter of the wire, without injury to the braid. Fusing-points of Metals and Alloys. (rennan xilrcr, used for rheostats, melts at about HHK> F. /<'//.SY- irircx to melt when heated by a current in excess of the one they are designed to carry are made of different alloys. l-'u^lhlt' (it///il(/.'> (\, or about l'J7 F. It consists of mercury, 1 part, and Aivet's metal, parts. }\'D<>(/'S /illoi/ melts at ()S ('., or 1 .">4 F., and consists of lead. '2 parts; tin, 4 parts; bismuth, 7 or S parts: and cadmium, 1 or '2 parts. Atrct'x n/rtdl melts at !U ('., or L'01 F.. and consists of lead. 5 parts: tin. .'! pails: bismuth, s parts. An (tllo'i nir/li-ni/ a/ 11!) ('.. or iMd F.. consists of tin. 4 parts: bismuth. "> parts: lead. 1 part. A-n ul/ni/ in F., consists of tin. 1 part: bis- muth. 1 part. 1 The insulation resistance of a gutta-percha covered wire is tested by immersing a mile or some fraction of a mile of the insulated wire, except at its two ends, in acidulated water. The tank must be of highly insulating material. ( )ne pole of a battery with known electromotive force is attached to a metal plate which dips into the liquid. The other pole is attached to a galvanometer or an electrometer from which a connection is made with one end of the wire to be tested. The other mid of the wire is outside of flic conducting liquid, and is not in contact with any conductor. The strength of current indicated by the meter furnishes a measure of the insulation resistance, the greater the resistance, the weaker the current will be. 14 210 MEDICAL ELECTRICITY AND RONTGEN RAYS An .~> ('.. or 334 F., consists of tin, 2 parts; bismuth. 1 part; or tin. 3 parts; lead. 2 ])arts. All these fu-il>le alloys are remarkable from the fact that they melt at a mudi lower temperature than any of the separate ingredients. The meltim:-poim of tin is -1-1 2 c F.:that of bismuth is 4<)7 F.. and of lead, til 2 F. The melting-points () f other metals and alloys used in electric instruments are: Zinc. 773 : F.; brass, 1X(><) F'.; silver. 1N7-T F.; copper. H~>4- F.: iron (wrought iron or iron wire). 32S6F.; nickel, 2^1)0 ; F.; platinum. :V_N(i : F. Solder consists of various alloys, the common tin-solder containing tin anl lead in proportions ,,f 2 parts of the former and from 1 to 6 of the latter, and is used for soldering coarse wires. Silver solder may be hard or soft, the former containing 1 part copper and 4 parts silver, and the latter 2 parts of silver and 1 part of brass wire. It is useful for solderim: fine wires and other parts of eleetrotherapeutic apparatus. The regular electric-light sockets and the lamps themselves or the plugs on the flexible cords leading to a movable lamp are so constructed that when they are in use. there are no oppositely charged surfaces exposed to accidental contact. Xo shock or short-circuit can therefore occur in ordinary use. \\hen the lamp is removed, two charged sur- faces are expiised: one. the metal cylinder into which the lamp screws, and the other, a metal spring which is raised or depressed by the key and in this way makes or breaks connection with a small metal surface in the base of the lam]). To test the wires and see if they are charged, the electrician will often moisten his finger-tip and press it against these two surfaces inside of an electric-light socket. If there is any current, it is felt quite sharply, and usually causes the hand to be drawn away by a reflex contraction. This takes place whether the key at that socket is turned on or not. If there is no current, it may mean thai the dynamo has -topped or that there is an imperfect connection vhcre between the dvnanio and the lamp-socket. Screwing the lamp it si li into the socket and t urn ing t he key is a more agreeable way ni testing f"i' current if a lamp is available. But there is no danger irom the use of the finger, ami no muscular contraction results which will pp-vent the fin-er being withdrawn at will. This would be danger- ou- if the person were grounded or if the voltage exceeded 2")0. I'o locate the trouble in case there is no current try other outlets ' -.:..< circuit. If they have current, the defect is probably in ' .'-' It. ' ithei a faulty connection with the two wires or an .:>'': metallic connections in the socket. The first is >cre\ving the wires fast in position: but the latter :':' - t lie use of a I lew socket . If 1 he 1 rouble is 1 ' I here is no current at ot her out let s on the .' I he lu.-es at the point where this circuit leaves ' have burned " : it. and if so, thev must be ' >r ! hey r.iav make an imperfect contact and r changed for new and ar tin 1 mam switch bv which the in ; t he st rert wires fn mi 1 he le no current aliv\vhere in t he i! turned "ft", and simply turning tu.-es at i In- j mint may have he DYNAMIC ELECTRICITY 211 lino being found to bo perfect, but the apparatus still receiving no current, a break-finder will be found invaluable. It consists of a 16-candle-power incandescent lamp in a portable socket, wilh two insulated wires which terminate in long metal points which are insulated except at their extremity. Beginning at the street mains, apply the two points to the bare ends of the mains or to the binding posts securing them. If there is any current there, the lamp will light up. If not, the electric-light company should be notified. If there is current in the street mains, turn the main switch on and test the two bare ends of the house mains at the point where 1 they are secured by the binding posts of the main switch. Finding no current there, it will be a simple matter to remedy the defective 1 contact which this indicates at the main switch. If there is current there, the next place to be tested is the other end of the house mains. The bare wires are to be touched by the two points of the break-finder, and if no current is obtained, it means a break in one of the main wires between this point and the main switch. This is very unlikely to occur if unbroken lengths of wire are used for these mains; but if there has been a joint in either win?, it should be exposed and will usually be found to be the seat of trouble. The two ends of the wire at this joint should be scraped bright and clean of oxid. and should be twisted together and soldered. The next place to be tested is the beginning of the circuit in which the current is lacking. Apply the break-finder to the two bare ends of these wires, and if there is no current there, the trouble lies in some of the connections right at this point where the current passes from the house mains through a fuse to the distributing circuit. Trouble here can usually be remedied quite easily by tightening screws or putting in a new fuse. Finding current in the ends of the distributing circuit at this point, investigate the ends of these 1 wires where they are fastened to the socket or knife switch for the apparatus. If no current is found there, the trouble is due to a break in one of these 1 wires. They should have been single lengths of wire 1 , and if they were not, the 1 imperfect connection should be sought at the joint which may not have 1 been soldered. Finding current in the wires at the 1 socket or knife switch and none in the apparatus, the 1 break-finder may lie applied to the 1 contact surfaces at which the current should (Miter the lamp-base or the 1 wires of the 1 apparatus. The 1 absence of current there indicates an imperfect connection in the socket or switch, and this is sometimes remedied by tightening a screw or bending a spring into better position, but it often indi- cates the necessity for a new socket. A pole detector (Fig. 105) makes a very conve- nient break-finder for anv part of the electrotherapou- tic apparatus itself. It will show tlu 1 presence as we 1 !! as the' direction of any cur- rent from 1 to .")()() volts. Connecting the two ends with two oppositely charged wires, the passage 1 of the current produces a chemic change in the liquid, resulting in a ivel cloud around the negative electrode. Its advan- tage 1 over a lamp is that it is sensitive 1 enough for the weakest therapeutic currents and will indicate 4 without injury the strongest currents eve 1 !' ap- Fitr. 105. Pole detector. Jl'J .Mi:i)H AL F.LKC TiunTY AND KONTCKX RAYS plied ID medical :ipp;iratus. No other apparatus covers so wide a range without requiring adjustment. It i> not suitable for the detection of the secondary currents of exceedingly high potential and great am- perage \\hich are produced by .r-ray coils, but it is not required for these current^. a- they manifest themselves in a striking manner if present. Pole Detector. The formula for the liquid is: 50 grams glycerin; 3 grains s;dt peter; -^ grams water: 0.5 gram phenolphthalein; previously dissolved in Id uranis alcohol. Pole connected with negative wire turns violet . /.'.;'< /'//>"/':< ft . (ium copal dissolved in et her and painted > ' in 1 \ ' ' . One ounce of shellac to eight ounces naphtha or .-I. This dissolves slowly, and should be filtered, adding - ...:.-: : changing the filters !o facilitate that process. u-' -ix minces of boiled linsei d oil and two ounces of spirits ' ' ' i II e . /'-'/.' ' . ( 'ot ton-covered wires are soaked in melted paraffin. eti ' roinaLTiiel coils ha\e a double layer of cotton thread, and coated wit h a t hick \ al'liish of sheila' 1 . '"/ I'ufi' r. Absorbent tissiii paper is rendered insulating M Ited jiaraflin. and is then suitable for use as the dielec- ir^e ci.mleu.~ers used in telegraphy and in connection with M 1 lei paper M. ill 1 inch thick, varnished with one and two parts -MM'- o| i urpeut me. is reipured i.-er "] ti , . coil. Two layers of t his paper are required ' i" iwerful coil- between the layers of tin-foil. These two thick- hed paper are about as thick as five leaves in this book. - i''' pan-d b\ soakinjr j,, Stockholm piich S nails M 'I DYNAMIC KLK( TKICITY 213 Wood is rendered insulating by boiling it in melted paraffin until bubbles of air cease to rise, 01 by painting it with melted paraffin. \\'u parts. It is used for joining the layers of gutta-percha in the insulated covering of wires and cables. The dielectric rit/idih/, or the voltage required to discharge through 1 mm. of air, is 4000; of mica. 61.000; of hard rubber, 55,000, and of resin oil, 20,000. But to have such great insulating power the oil must be entirely free from water and acids. Tapping a Line for an Additional Outlet. It will often happen that one or more outlets are desired from a pair of 1 10-volt wires besides the outlet in which the wires terminate. This can usually be done without disturbing the wires except at the point where they are to be tapped. For instance, if the wires are laid in molding, the capping is removed and the wires lifted out of the wooden groves for a few inches. The current should have been shut off at the main switch, and if there is a possibility of this being turned on by some one else, the fuse plugs of this particular line had better be removed. It would be absolutely wrong to handle bare live wires with metallic instruments. Each wire is tapped separately. The insulating cover is stripped from the wire for about an inch, and the wire is scraped free of oxid. The end of the wire that is to be fastened to this has been similarly prepared and is wrapped several times around the Hue wire. The joint should certainly be soldered, and this is done by first painting it over with a xolderitig fluid, such as: Saturated solution of /inc chlorid, 5 parts: alcohol. 4 parts; glycerin, 1 part, and then melting a small amount of solder over the turns of wire. All the bare wire 1 should be covered with several layers of insulating tape, and the wire pressed back into the wooden groove. The other wire having been tapped in the same way. but at a distance of about an inch from the level of the first, the capping of the molding is nailed down in posit inn again. The two side wires should not be flexible wires leading directly to any apparatus, but should be inclosed in molding and lead to a stationary switch-board or receptacle. At the place where the line is tapped the side wire from one n( the line wires has to pass over the other line, and in doing so 11 should be outside of the wood capping. It is often desirable to apply a short length of flexible loom or of porcelain tubing covering one wire where it crosses t he ot her. The 1 10-volt alternating current is supplied in the same way by a three-wire system. It is a current which produces a much more marked physiologic effect than the direct current, and so the wires should be 21-1 MKDICAL KLKl TKK ITY AM) K<")NT<;KN KAYS handled more carefully. While the cautious use of the finger is per- mi-sible a- a means of testing the presence or absence^ of current, still it will be found less disagreeable to use a lamp, a break-finder, or a pole detector for this purpose. Such a current will not flash across any- greater -pace than the 1 ID-volt direct current, and requires exactly the same -oil of wiring. It may be used directly for running motors of special con-truction, for diagnostic and therapeutic lamps, and for electric baths.. It- tension i.- regulated by a volt controller, and its intensity or amperage by a choke or inductance coil. It may be made available for .r-ray and high-frequency currents by means of a rotary trail-former or electrolytic rectifier and suitable accessory apparatus, as was fir-t done in the d'Arsonval-Gaiffe or the Snooks or Kny-Schcerer outfit. It is not directly available for most forms of electrotherapy, and especially not for elect rodiagnosis where a polar effect is often essential, tint it may be used to run a motor generator from which a suitable current with a fixed polarity may be obtained. It may also be used to run a motor transformer yielding a sinusoidal current, which has very marked therapeutic properties. The intensity of an alternating current may be measured by means of a hot wire milliamperemeter. The current or a shunted portion of the current passes through a wire whose increase in length under the influence of heat causes a corresponding motion of the indicator. The in-trument is graduated by experimental comparison with a standard in-trument. The wire is heated by a series of currents in alternating directions, very much as it would be by a scries of currents in the same direction. The voltmeter for alternating currents must also be a hot- wire in-t rument . Taking t he number of volts and of amperes indicated by the two instruments and multiplying these together to obtain the indicated number of watts produced by the dynamo, it will often be found to exceed the amount of power expended in running the dynamo. Tin- hot wire milliamperemeter evidently does not register the average strength of the currents passing through it in alternate directions, but tes somewhat more than the true figure. The repeated surges heat pi dui'ed by the maximum current are more effective than t he d'-ncv on the part of the wire to cool during the instants when the 1 ' ' i- /!'' i. Trolley-car Currents. The .">()()- or .">.">( )-volt direct current of the . used for electric arc-lamps in the street and public -udi high potential that it will leap across a considerable dangerous effect upon living creatures. Death nt passing through the body bv accidental oppM-iie]y charged bare wires, or \ynli one bare wire " i! 'i cotin"ciioii. Tin- person may escape with only n i' he i- in a partially insulated position and The wires are not only a direct danger, but ires, telephone or telegraph, may fall across an being-. lf() times the amperage, and would require 400 or !)()() times as great a conducting path. Accord- ing to .Joule's law, the amount of heat disengaged in a given time is directly proportional to the square of the strength of the current and to the resistance. The strength of the current means the number of amperes or milliamperes. It will readily be seen that the higher volt ani's are an absolute necessity when it comes to a matter of transmitting thousands of horse-power as an electric current. These tremendous voltages, ot course, need the hrnrfmt kind of insulation wherever they touch any solid support, and require that the conductors should not be on the surface of the ground, and that they should he far enough apart from each other or tn>m other metallic conductors to prevent the current from leaping across the air-space which forms the insulation. Accidental contact of human beings with the metallic conductor.- should i?lti MKDK AI. Ki.KeTKieiTY AND HOXTGEN HAYS lu 1 mo-t effectually guarded against, as it would certainly be fatal. ( 'urrents >f such tremendous voltage are always modified hy a step-down transformer before entei-inir tin- powe: -house, where they are further acted upon hv rotary converters and changed into a direct ciiri'ent of .').">( i vohs for the trolley line. and of other voltages for charging storage batteries and fur elrciric lighting. Almost any bare wire or binding- |i - in -uch a power-house is charged witli a current which would make intact extremel dangerous. There is also a great amount these lii^h voltages and rapid alternations are present, effects are produced. One is a magnetizing tjhct upon using them to run irregularly, and another is an effect upon ni "..- .- .*?< '" of the operatives, producing symptoms of neuras- .:;:. The air of the room is kept warm by the conversion into heat certain portion of the electric current passing through the various iii- i >f t he apparatus. The best conductors are those which transmit an electric current the least ohmic or, in other words, frictional resistance, hut there i- ;il\vavs some resistance 1 , and in the case \ve are considering the resist- ance is iioi only a measurahle hut a large quantity. The electricity lost hy ohmic resistance is converted into heat. Special attention is always paid t" arrangements for the dissipation into the air of the heat produced by ohmic resistance in the wires forming part of dynamos and motors. A rise i .">()- F. in the temperature of the apparatus is regarded a.- t he limit of safety. The hotter a body becomes as compared \viih the surrounding atmosphere, the more rapid becomes the dis- sipation of the heat. In an apparatus through which the same amount uf electricity passes every minute ami in which, consequently, the same amount of heat is tienerated every minute, the maximum tem- peraHire attained is the temperature at which the rate of dissipation : deal becomes eijiial to the rate of heat-production. The room in which all these great dynamos are in operation is so warm that no artificial heat is required, and the doors and windows are left open. The ureat copper bars forming the ground connection or return circuit fi'Min the trolley-car rails to the dynamo carry a tremendous amperage, but a very low voltage. These can be touched with the bare hand, and are found to feel quite warm from the friction of the electric current pa --in si through them. One of these bars carries a current -utheieiii in kill 1 ou men, hut its ground connection and approximately zero voltage make- it- pres-uiv so low that the amount which will pass through the human hodv i- not sufficient to produce a perceptible sen- ount i- found 1 iy dividing t he voltage by the number of MI the body, and i- not exceeded no matter what may an i per; tire of t he generator. i ill current i.f the trolley-car circuit or the 10.000- i for long-di.-tance 1 ran.-miion of power pa->e- ent lamp upon a writing desk. And just as current u ill cau.-e heal enough to vaporize er currents \\ilh lieavier voltages and struct ive incfiagrations when short-circuited. are always employed, breaking the circuit ive current be^in- to flow throuirh the line. DYNAMIC ELECTRICITY 217 A circuit-breaker is like ;v knife-switch, which is thrown wide open by the action of ;in electromagnet which is not strong enough to throw open the switch with any ordinary current, but becomes so under the influence of an abnormally strong current. A common use of the circuit breaker is in an automatic cut-off ar- ranged to break the circuit in case of an excessive Mow of current. A powerful spring tends at all times to press the control lever over to "off," or the position of no current. When this lever is pressed over to the place of maximum current flow it is held there by a powerful electro- magnet. Forming a part of the same apparatus is another electro- magnet which tends constantly to actuate a circuit breaker, but is opposed by a spring which may be set so that it will yield to more than a definite strength of current. An excessive current causes the circuit breaker to act; the electromagnet loses its power to hold the resistance lever, and the latter springs back through the positions of greater and greater resistance 1 to that of no current. This is part of the equipment of any powerful x-ray generator. The induced currents produced for therapeutic application by a faradic coil are of a higher voltage, and correspondingly lower amperage than the primary current. The faradic current will, therefore, over- come the resistance of the dry skin, and two dry uncovered metal handle's held in the hands will transmit a current through the 1000 ohms resistance of the body. A voltaic current of the usual voltage would not be transmitted in any effective amount under the same conditions. The faradic current is usually an alternating and an interrupted one, and each impulse varies in voltage from a maximum to a minimum. Methods of measurement of the voltage arc 1 by the use of a faradimeter or of an electrostatic voltmeter. The latter depends upon the attrac- tion between two oppositely charged bodies, while the faradimeter is composed of two coils between whose ends a bundle of soft-iron wire or a coil of wire is freely suspended. The soft-iron core tends to assume a position parallel with the long axis of the coils, and indicates upon a dial the strength of the current passing through the coils. The strength of the current is, of course, dependent upon the voltage. Either of these appliances probably gives an approximation to the maximum voltage and not the average voltage. Measurements have been made which indicate that the potential of a faradic current, while actually being applied to a human being, is about 10 volts, while other measurements indicate that the difference' in potential between the' two pole's on ope'ii e-hruit is about 90 volts. As it take's a voltage' of about 10,000 to spark across* an air-space of an inch, the spark to be obtained from 10 volts would be only ,,/,,,, or ..-j-, 1 ,;,, ine-h long, ami that Iroin 90 volts about -, , 1 M) or 3 / M , inch long. And this is about the result obtained when the two bare ends of the wires from a faradic coil are' brought together; it is difficult to get any spark at all e'xcept by rubbing the ends over each other and securing an imperfect contact. It is hardly possible to hold the e-nds at any distance apart and secure- a continuous strc'am of sparks. With the strongest therapeutic faradic current the sparks that can be obtained are little bright points without noise and without any c't'fect upon the metal points. The' amperage is very small indeed. As in the case of the voltaic current for medical purposes, the' wire's carrying the faradic current ivquiiv nothing but the thinnest complete layer of insulating material. MKDICAL KLK( THICITV AM) ROXTGEN KAYS The Different Wire Gauges. The one usually referred to in America when the si/e of a wire is spoken of as such a number is the Brown and Sharpe wire gauge (B. S. (1.). For example, the No. 3(> wire so generally employed for (he secondary coils in faradic or rr-ray apparatus i- No. oti B. and S. The other gauges are British Standard (Jaime (S. \V. (I.): the Birmingham Wire ( Jauge (B. W . (',.); and the French Wire (Jaime ( F. W. (i.i. In addition to these gauges in which wire i< referred to by number, the size of a wire may be designated In- stating it^ diameter in fractions of an inch or in millimeters. NIL :>> (]>. and S.) is ().()().") inch, or 0.1 millimeter in diameter. Its equivalents are Xo. 10 (S. W. (!.) and Xo. ''>") (B. \\'. (I.i. It is used fur the secondary "f induction coils. \o. '2'2 i B. and S.i is o.0_'.~>:> inch or 0.0 millimeter in diameter. Its equivalents are Xo. 2:! (S. \\'. (',.). Xo. 2M ( B. \\". (J.) and Xo. 1 i F. \\". (i.). It is useil in the primary windi.-g of induction coils. Xo. 1 1 ( B). and S. ) is O.Oli 1 1 inch or l.l> millimeters in diameter. Its equivalents are Xo. Ki (S. W. (i.). Xo. Hi ( B. W. (J.). and Xo. 11 ( F. \V. ('<.<. It i- used for the house-wiring, passing from the mains to individual elect ric-li.Liht sockets. Xo. lo ' I >. and S.) is o. 10 1 inch or '2.1 millimeters in diameter. Its equivalents are Xo. 12 (S. W. (J.). Xo. 1_' (\>>. W. (i.). and Xo. Hi ( F. \\ . (J.). It is a suitable si/e tor the house-wiring leadmii from the mains to the switch-board for an /-ray coil or to an arc-lit^ht . It is heavy enoiiirh even fur the main- for an elect r< (therapeutic installation, ided that not more than about 2"> amperes of current in the various apparatus are ever to he turned on at the same time. Xo. s i B). and S.i i-0.1_N.~> inch, or .'!.-! millimeters in diameter. Its equivalents are \o. 10 (S. W. (i.). Xo. 10 ( B. W. (J.), and Xo. Is I-'. \V. (i.). It i- .-uitable for the mains for a complete elect n>i hera- peutic installation, indndinfi .''-ray. sire-light, and electric-light baths. but not to exceed 100 amperes at aiiv one time. is DYNAMIC KLECTPTCITY 219 Conductivity of Metal Wire*. The specific conductivity of pure silver wire is taken as 100, that of pure copper wire is 80, and the con- ductivity of copper wire suitable for electric work, 95 per cent, that of pure copper. The specific conductivity of silver is 100; copper, 80; gold, 55; xinc, 27; tin, 17; iron, 14; palladium, 12.5; platinum, 10.5; lead, 7.8; antimony, 4.3; mercury, 1.6; bismuth, 1.2. This means that under identical conditions as to voltage and size and length of wire the strength of current transmitted will be in the proportion indicated by the specific conductivities. Units of Resistance.- In the ('. (i. S. system the unit of resistance is that of a pure copper wire one millimeter in diameter and TTOIM/TJ millimeter long. In the system commonly employed the unit of resistance is the ohm, which is equal to the resistance of a pure copper wire one millimeter in diameter and 48.64 meters long. For other values of the ohm see page 49. The Specific Rcxixtancc of Metal Wirex. The specific resistance of pure copper, or the resistance of a cubic centimeter at C. is 0.000001642 ohm. The specific resistance of the various other metals is a matter of simple calculation based upon a comparison of their conductivity with that of copper. For instance, platinum has about one-eighth the specific conductivity of copper, and has, therefore, about eight times the specific resistance. A pure copper wire 1 square centimeter in cross-section and 1 centimeter long has a resistance of 0.000001642 ohm, and 100,000 times that length, or a kilometer (equal to 3280.9 feet) of the same wire would have 1 a resistance 0.1642, or about ,'; ohm. /iV.svW /V/i/y is expressed in ohms per circular mil. foot (conductor 1 foot long and with a circular cross-section i,,',,^ inch in diameter). Current denxiti/ is expressed in amperes per square inch of cross- section or 0.000001 ampere per circular mil. TABLK OK TIIK RK.SISTANVK OK IHKKK.KKXT MKTAL WlKKS. RESISTANCE or A WIKK 1 MKTKK I.OM, ANI> 1 MlI.I.I.MKTKH IN DlAM- ETER. 0.01'.i:;7 ohm ().020.-)7 " 0.021 '),")() " O.o:i7.")l O.lKidO ' 0.1 2.") 10 ' 0.2.V2(>0 1.22170 ' APPROXIMATE N XMI-: or MKTAI.. CoMI'AU \TI\ }'. RESISTANCE. Silver 1 1)0 < 'opper. . 1 .01) [ 1 Cold Aluminum 1 'M I'lat inum (i.OS Iron (i.XO Lead 1 ''> (iO Mercury, liquid ' HTiuan-Mlver i copper. t: nickel. 2: /.inc. 1 . part< i. 7 '*'' I he resistance ot any Icngih of wii'c of ;ni\' dianu'ter may lc cal- oulated troin this lable. .Mulliply the I'csistance of one nielei 1 . as iri\-ct : abov(\ hy the mimlier of meters, and divide by the square of the diametei expressed in millimeters. Thus the resistance of a copper wire V, millimeter in diameter and ion. ()()() meters Inng would be found by ilu- following e(|uai ion: 220 MKDIfAL KI.KC THK ITY AM) RONTGEN HAYS This is the -i/e. No. o<>. B. \V. (i., and length of the secondary wire in >ome Ill-inch induction coils. The 'J(M ).()()() ohms resistance is what might be termed the frictionai resistance, and causes loss of power by convert- ing a certain amount of the electric energy into heat. The other im- pedence to the ilo\v of the current is inductance, and is dependent on the number and arrangement of the number of turns, not on the length and thickness of the wire. It is not under consideration at this place. SL'/n fcn'td.- Simple experiments show that a charge of static electricity i- practically all upon the surface, due to the repulsion of charges of the >ame polarity, \Yith dynamic electricity the direct current shows practically no skin effect, but with 1 lie alternating current tin.- effect i- very marked. The current is to a large extent confined to the surface of the wire and comparatively little is transmitted by the interior of the wire. This reduces the conducting capacity and has the effect of increasing the resistance of the wire. This cannot be overcome by lining a stranded conductor, the resistance from skin effect remaining the same. Hut a I a rue wire sometimes is made with a non-conducting core -ii that the same weight of metal with a larger surface for conduc- tion will have le/>/. -'.' required i- II. and /' is the radial thickness of the insulated wrap: 'in ^ I the wire. I he diameter \\ . 1 1 1 1 > i .!-. - L iii, i n 1 1 1 1 1 a n i et e r ol t lie w i re, m- ' 'r another torn nila i-: add t he t hickliess of t he ' : ejej- ,,]' t he core . ititside of its itisulat ion, mult ipiy by ' ' 1' :. L 1 ' :.. and a Ha in by t he I hick ness of t he coils f A a i. 1 ' . t hi -qiiari o| t he diameter i if t he wire. DYNAMIC KLKCTKICITY 221 The number of turnx of wire in n coil is found by multiplying the thickness of the coil (A a of the previous paragraphs) by its length and dividing by the square of the diameter of the wire. The total treit/lit or rcxi*/a-ncc is easily found from one of the printed tables if the length and diameter of the wire are known. fcjl'ccl of Temperature n/>on ffcxixtctncP.Thix has to lie taken into account in some of the commercial uses of electricity, but it is so small that it mav be disregarded or only approximately calculated in electro- therapeutics. The resistance of a copper wire increases about one-fifth of 1 per cent, for each degree F., or 1 : \ 1 S of 1 per cent, for each degree ('. that the temperature rises. A Gorman-silver wire shows an increased resistance of only one-twentieth of 1 per cent, for each degree ('. that the temperature rises. Tin Production of II eat m ( 'ortducfitif/ liV/v-N. The ohmic resistance of a conducting wire is a measure of the power which would be required to simply make t he current flow 1 h rough the wire if the wire were st might and uninfluenced by any other object. This portion of the power from the generator corresponds to the power lost bv friction in ordinary machinery. None of the elect ric power so consumed is act ive in inducing other currents or in causing mechanic motion. It is converted into heat. The heat produced in this way varies directly as the resistance and as the square of the current or amperage. The power wasted in simply overcoming what mav be considered the frictional resistance to the passage of the current through the wire also varies directly as the resistance and the square of the amperage. The following formula enables one to calculate the number of horse- power wasted in the form of heat by the passage of a current of elec- tricity through a wire: II P = r-R y., 0.001:54. 746 The actual amount of heat generated in a given time. T. is equal to ("-'RT>: 0.240") (gram-degrees). In this formula (" is the square of the number of amperes. R the number of ohms resistance, and T. the number of seconds that the current flows. The product of these three factors is to be multiplied bv 0.210.") to find the number of gram-degrees or calorics. One calorie is the heat required to raise the temperature ot one gram of water one degree ( '. 'I In ///>( uj TI ni/n ratun in a ( 'OIK/ net / n D or ill) 3 F.. no matter how loiiii the current flows. A good empirical rule is that a copper conductor 2 inches in diameter will safelv carry a current of 21 )l !0 amperes, and that the sate carrving capacitv of wires of greater or less diameter vanes as the square root of the third power of the diameter. An example oi the application of this rule would be in finding the safe carrying capacity of a Xo. 1 1 l'>. \Y. ( i. wire, which is about O.Os inch in diameter. ( 'ailing the unknown carrving capacitv A 222 MEDICAL ELECTRICITY AND RONTGEN RAYS 1 2 :t " : i O.OS' : : 2000 : A". ! 2" .V j O.OS 1 2000. ! O.OS :1 2000 2000 0.022(13 A Xo. 14 copper 'wire will accordingly carry a Hi-ampere current without overheat ing. I.FNV.TH. \VI-:K;HT. AND RKSISTANCF. or COPPER WIRE. iNi> WKK.HT. Pot Mis I'KR w. <;. WK.II;IIT \M> 1 . E N i .T H . l.KVCTH AM) KKSISI ANCK, RESIST.* < hl.Ms I'Kli l'i H M I'KH < >HMS 1'1-:K Mll.K. MILE. I'oi vi). X 13."). 0(1 2.00 0.00460 in 2s7.UO 3.03 0.01058 14 IS'UHl 4..")0 0.02416 20 I'.t.OO 44.49 2.27254 2 t 7. SO 112.02 14.55700 30 2.30 37S.;.l 164.46500 30 0.2") 3400.00 13200.00000 Tin flmt i m/ i'j Coil* of \Yirc h/i a Current. The heat develojiod in clnsrly \viiuiid mils of wire, as in dynamos and .r-ray coils, finds a com- paratively small radiating surface, practically only the outer surface of the outermost layer, and a greater rise of temperature will result. A rise i if .")()- ('. is considered safe for the wires in the electromagnets of a dvnamo. (ienerally speaking, wires are considered to be over- heated when they are too hot for the hand to lie kept upon them for a minute at a time without discomfort. Bobbins of the same size' when wound with wires of different calibers contain a length of wire which is inversely proportional to the square ot the diameter of the wire. The resistance m such bobbins is inversely proportional to the fourth power ol t he diameter ol i In wire. T< i -ecuiv equal heating in t he I wo bobbins the current strength in ampere.- divided by the square of the diameter of tin' wire should give the same number in both. NATIONAL HOARD OF FIHK r.NDKIUYKITKKS' TABLK OF C\HRYlN(i CAPACITY OF \YIHF.S. Is : i .1 Hi s M 12 1C, 12 17 23 in DYNAMIC ELECTRICITY 223 The safety limits arc those within which there is no danger of injuring the insulation of the wires in the coils. Coils in which the wire is 2 millimeters in diameter can safely carry about 15 amperes; and with wire 5 millimeters in diameter, about (H) amperes. The lower limit is specified for rubber-covered wires to prevent gradual deterioration of the insulating property by the heat of the wires, not from fear of igniting the insulation. The question of drop is not taken into consideration in the foregoing tables. No smaller wire than No. 14 should be used for regular wiring. "Circular mils" refers to the area of cross-section of the wire. One mil is one-thousandth of an inch, T7 j' nTr inch, or 0.001, and the area of a square which is one mil on each side or one square mil is 0.001 X 0.001 =0.000001 square inch. One square mil is 0.000001 square inch; 1624 square mils is 0.001620 square inch. The area of a circle which is 0.001620 square inch is also denominated 1620 circular mils. The area of cross-section of a No. 18 B. and S. G. wire is 1620 circular mils, or 0.001620 square inch. Each mil in the diameter of a wire indicates 0.001 inch. Each "circular mil" in the area of cross-section of a wire indicates one-millionth of a square inch. The Insulation of Wires. This includes all the means which are taken to limit the flow of electricity as much as possible to the wire itself, and the apparatus to which the current is led and through which it is intended to flow. Leakage of electricity may take place from one charged wire to another, or directly or indirectly to the earth. A wire may be insulated by being merely suspended in the air at a sufficient distance from other conductors. The required distance will depend upon the voltage of the current, a difference of potential of 10,000 volts between a wire and another conductor causing the current to break through the insulation of about an inch of air. Air insulation is good enough for all practical purposes, and is depended upon for telegraph wires, except at the points where the weight of the wire must be sup- ported. The fact that the air is a poor conductor of electricity and may, therefore, be used as insulation, makes the installation and con- struction of electric apparatus much simpler than if every wire and switch and binding-post and screw had to be protected from contact with the air. Hare wires may run in grooves in various insulating materials, such as marble, slate, hard rubber, or ivory, in stationary positions, where they are not exposed to accidental contact with other wires. The connections in the ordinary double-pole knife-switch are made in this way. One wire from the battery or dynamo is secured by a binding-post which projects from the face of the slate base. The continuation of the circuit is formed by a bare 1 wire laid in a groove on the back of the slate or marble base from the concealed end of another binding-post, which carries the hinge at one end of the gap. bridged across by one contact blade 1 of the knife-switch. From this hinge the current follows the Contact blade to the contact jaws, goes through the metal support to a wire which passes along the under side 1 of the base to be secured to the concealed part of another binding-post. A wire passes from this binding-post to the apparatus. The return current follows a similar parallel path back through the connections on the opposite side of the double knife-switch. On the under surface of the marble switch-board of a cabinet for voltaic and faradic currents there are sometimes a dozen bare wires running in grooves and forming the '_ )- _M MKDICAI. KLK< TKlriTY AND H<")NT(iK\ HAYS connection between the various metallic binding-posts, switches, meters, ami resistances on the face ot the switch-hoard. The old idea of tin 1 earth as a universal reservoir of electricity into which either positive or negative electricity may be allowed to escape and will be immediately neutralized is quite a good one as a working hypothesis. Take the case of an insulated conductor like a single telegraph wire; if one end of the wire is grounded, and one pole <>f tlic battery is grounded while the other is connected with the telegraph wire, a current will flow through the battery. and a meter which mav be placed in the circuit and through the telegraph wire and back through the earth to the other poll 1 of the battery. The nature of the transmission through the earth which receives thousands of different currents from natural and artificial sources nm.-t be very complicated. The hypothesis which offers the easiest explanation is that the earth at any point stands ready to supply a deficiency in either positive or negative electricity, or to remove a surplus of either kind. Demonstrable currents of electricity are iced in the immediate neighborhood of a grounded wire, and these are tiie ones which destroy gas- and water-pipes by electrolysis in the neighborhood ni the electric railways. Leakage through the insulation al'>ng the telegraph forms an earth current which returns to the battery, and ii there i.- no other connection, the amount of current passing through the meter will be simplv the amount of leakage. From Ohm's line i- found by dividing the electromotive force of the bat terv in volts bv the leakage current in amperes. The standard insulation resistance of telegraph lines i- 'Jon. I nil) ohm- per mile. Km 1 instance, the electro- motive force from a battery of I'd cells will send a total current of only about ,',, milliampere through all the different slight leakage points oi ,-i milr ui t .T 'gra] >h line. '/'A. //< .flnnn f (ilnst: tiiul I'timlitin Itiniiltitors.- Tliis is exceedingly and for elect fol herapeut ic purposes these >ubstaiices may be regard* d a- absolute iii in-ci inductors. II" /" ilii/iuti Hi xt." thai the in.-ulation ivH-latire in megohms I.""" 11 ' 1 " ! ! ile of glltta-percha-covei'ed wire is e.pial t"o jrjl) the number found by dividing I he outside by ihi Lian eter o| t he conduct ing wire itself in mils. DYNAMIC ELECTRICITY 225 \\ ires from No. IS to Xo. l(i, if insulated by gutta-percha or rubber, which has much the same properties, require a coating at least J.,- incli thick, and should have an insulation resistance of at least 100 megohms per mile at a temperature of 70 F. Nos. 15 to 8 require an insulation /, inch thick; and Xos. 7 to 2 an insulation -,',<- inch thick. These are for voltages between and (iOO. and for electrotherapeutic purposes gutta-percha and rubber may lie regarded as absolute non-conductors. Tin- Electrostatic Capacity <>J (rutta-percha Insulation. A wire with an insulated wrapping forms a condenser. The metal forms the inner armature, the- gutta-percha the dielectric, and the surrounding sub- stances the outer armature. When an electromotive force is applied to the metallic wire, the primary effect is to charge this condenser, and then later comes the passage of a current through the conductor. The capacity of a condenser depends partly upon the size of the two arma- tures, or outer and inner conducting coatings, but also to a very great extent upon the material, size, and thickness of the dielectric. The dissected Leyden jar (p. 27), in which the charge remains upon the glass after both outer and inner coats are removed, illustrates this fact. The electrostatic capacity is from 0.2400 to 0.3945 microfarad per mile. The larger figure is in the case of a wire in which the outside diameter of the insulation is only 2.50 times the diameter of the metallic wire; and the smaller figure is found when the outside diameter is 4.50 times the diameter of the metallic wire. The electrostatic capacity of a \vire limits the rapidity with which impulses can be sent through the wire. If the full strength of the current is suddenly turned on, there is not an equally sudden impulse produced at each part of the line corresponding in time of occurrence to the distance from the generator. Besides the delay due to the distance traveled by the electric impulse, at the same rate as that of light, about 1S5.000 miles a second, there is a delay due to the fact that the condenser formed by the 1 conductor and its dielectric and the surrounding media must be fully charged before the full strength of the impulse can reach any distant part of the line. The result is an impulse represented graphically by a slanting instead of a perpendicular line. The same phenomenon occurs when the current is turned off. The electric tension at any part of the wire does not suddenly subside at a period of time corresponding to its distance from the generator, but subsides only gradually as the con- denser charge is lost. If the successive impulses are too rapid compared with the electrostatic capacity of the wire, the condenser charge does not have time to disappear between impulses, and an approximately constant current is the result. In telegraphy this limits the number of signals which can be transmitted to those corresponding to 135 words a minute. Wires used in elect rot herapeutic apparatus, if of sufficient length to possess an appreciable electrostatic capacity, are almost always used in the form of coils, and in these the effect of other inductive influences overshadows that of the electrostatic capacity of the wire and its insulating material. Tin.' /WNN of }'nxul// Marble and Hard Rnblnr. It will sometimes happen that a high-frequency apparatus will cease to work in consequence of the fact that the marble front or top which forms a base for the binding-posts leading from the outer coats of the Levden jars to the resonator, and for the binding-posts leading tmm th<- inner coats of the Leyden jars to the spark-gap, has lost its insulating -_ti MKDICAL KLKCTHICITY AND KoNTCKX HAYS properties. The commonest cause of this condition is the absorption ot' moisture l>y the marble, and ils becoming thus a sufficient conductor MI' electricity to allow the high-tension currents to pass along the marble instead of being compelled to cross the spark-gap. This may occur without the presence of a liquid in the Leyden jars, and also with a wooden or a hard-rubber switchboard. The marble slab shows this condition to the eye, especially if the surface is unpolished. It looks wet and streaked, and the finger can rub off a saltv or acid-tasting deposit. Prevention is better than cure in such a case, since after the marble has once become a conductor, it is very difficult to make it an effective insulator again. Four days' baking will certainly drive out every particle of moisture in the marble, but will not restore its insulating properties. It is a good rule not to use any liquid inside the case of an x-ray coil or high-frequency apparatus, and especially to see that there an- no imperfect contacts, with their consequent sparks and nitrous fumes. It cannot vet be stated positively whether this disagreeable accident i- due to ordinary chemic processes entirely, or whether it is due to a process of ionixation of the marble itself, whereby it has permanently acquired the property of conducting electricity. In the first case, we ma\ be able to di-.-ol ye out t he disturbing chemic compounds by soaking in some solution and then drying the marble. In the second place, we .-hall have to adopt the present plan of discarding a piece of marble which has once lierome a conductor. In the case oi hard rubber the surface attracts moisture and dust, and be.-ides undergoes a carbonizing process in the presence of high- frequency eliliivia. so that this substance is not more permanent than marble for the purpose under consideration. ' ila-- may prove to lie successful since, so far as known, the changes it undergoes aftect onlv the -urlace. causing a certain roughness tavors the deposit ot metallic nitrate- and dust and moisture. I'- m.-ulat iM<_r qualities are probably restored bv washing the deposit off the surface. Thi- has not been definitely settled yet. 1 he peculiar character ol the current which we have to control in Hii- case i- shown ! r. l he fact that a vivid white -park will often be seen at a bindinjr-post. 'I he screw may be turned down as tight as possible, and -till the thin film of o\id between the two metal surfaces will offer deuce to cause the current to leap across an air-space of 1 ' ract ion i if a n inch. \ lightning arrester i- always required when wires enter a building above ground. It i- an arrangement lor leading a charge of high- tension atmo.-pheric electricity to the ground, instead of allowing the pa-- into the hoii-e along the wires, with danger to the and occupants. The general principle j- to have dated \\ire, a- ln-;ivv as \o. Hi. thoroughly well grounded, and DYNAMIC ELECTRICITY 227 terminating in a metal plate with saw teeth supported upon the same insulated base, with a similar metal plate which forms part of the electric supply circuit. The sharp points of the two plates an; bare, and only a fraction of an inch apart, but normally none of the current will leave the electric circuit and leap across the non-conduct ing air- gap between the two sets of points. The high-tension charge of atmos- pheric electricity, however, with its enormously high frequency (millions of oscillations a second), flashes across this space and is safely led to Fig. Kid. Westillghouse electrolytic lightning arrester. earth. It is true that the ohmic resistance of the air- gap is infinitely greater than that of the win's in the various instruments, but the high tension makes it possible for the atmospheric electricity to overcome this resistance. Currents of extremely high voltage and extremely rapid oscillations are 1 subject to an in- ductive 1 impedence which will cause 1 them to leap a considerable air-space and follow the shortest path rather than follow a long conducting path, even though the latter has ample carrying capacity. Another form of lightning arrest eM 1 is made 1 by wrapping half a elo/e'n turns of insulate 1 *! wire 1 aremnel the elect rie'-light wire 1 before it enteTs the 1 house 1 . The 1 other end of this insulated wire 1 is grounded, as in the 1 first type 1 of lightning arrester, by being solelered to a metal water-pipe or to a mass of iron buried in a pit filled with dam]) charcoal. fclcctroliitic Liijhtm'mj J/'/TN/rrx. These 1 afford a short chvuit for the cunvnt wheneveT it becomes of a sufficiently high voltage 1 to over- come the 1 resistance 1 of the 1 liquid. The 1 resistance 1 can be so delicately adjusted that e'ven a small percentage of increase' over the 1 ordinary operating voltage 1 will be 1 prevented from passing into the house circuit (Fig. 1 tid"). The' principle' is the >anie as in the familial 1 electrolytic interrupters used with .r-ray coils. c. r. too j/j. ^/o ' Zoo so 190 SO /So '7o 70 J60 /fo (,0 /4-o '3 f '3.0 I/a +0 too fo -*- ao 20 7o to to SO 4o o 24 3.0 -10 10 o -20 -/o Fig. 167. C igrade a ul 1'a illicit thennon ic scales. en hr et 22S MF.niCAI. KI.KtTKiriTY AND KONTCKN RAYS YAU'KS OF KNCI.ISH AM) MKTR1C MKASTHES. One meter = :i LNd'i feet =--- 3t.:*7 inches. One centimeter _o.:Wo7 incli. or about ,'',, inch. One millimeter 0.001 meter ^().do7 inch, or about ,,';, inch. One kilometer 1 (MM) meters = about ^ mile. (Mir t;ram l.l.lo'J i;raiu- .Tn>y . On,' kilojrram UMMI Lnvim- - .Jit pounds Avoirdupois. < )ne cubic centimeter 1 c.o.1 ^O.Oiilo:; cubic inch. One liter KM Ml c.c. > ill .(>:! cubic inches -=().Ns()4 quart. ( die decree ( Vlltiirrade = '-, decree Fahrenheit. (I (Vntmrade :;_' l-'ahrenheit free/inu-point of water. KM) < 'entiiirade '-'1'-' 1 -'ahrenlieit =- boiling-point of water. Idd Fahrenheit :',7> ('. :'.'.' Fahrenheit = :'.> ( '. -- maximum density of \vater. ild- Fahrenheit = l.").."r" C. = temperature at which electric resistances are USUallv measured. MEASUREMENTS OF RESISTANCE Different substances have specific conductivities, and a conducting path consist ing "f a i:iven length and area of cross-section will present a resistance which may be calculated by reference to a printed table. Any change in cheinic composition '' V( ' r - 'I'l'i* i s ''"' solution which is used as the electrolyte in the liquid interrupter for .r-ray coils. The smallest admixture of any other .-ubst atice multiplies the conductivity of water to a perfectly enormous extent. The electric resistance of a disk of pure water 1 millimeter thick is as that of the insulation in different parts of the apparatus and in the covennu: oi the wires. Another is the internal resistance of the battery. These two tests are sufficiently described on pp. 90 and 229 ier is the resistance of the wires themselves, while others are those oi the li\ mi: tissues, especially the skin, which is highly resistant, and tin resistance o' physiologic tluid>. such as the urine and blood. Testing Resistance by Simple Substitution. An unknown !-:- a'M-e. |;. i< connected iii series \\ith a constant batterv and a [galvanometer, (i. and the current strength is noted. Then a standard resistance, 1;'. -ubstituted for the unknown resistance, and is varied until the L r :u' aliometef shows Thai the curi'etll SlrelltTtll is I lie same as 111 I lie Jir-t Itlst atice. 1'hen 1 ,' I ! '. I' ma\ not always he practicable to vary the standard resistance so a.~ i" make the current equal to the one to be tested, and in that case a 1 i- ' be n ade. i .ase,] upon t he relal ive si re n ill li of the current -.', it h t:i< two d it'f e rent resistances. If ,/ j^ the deflection obt ained with the n resist ..me!-, and '/'.that nblained wit h t he -l andard resist - ance. and ( > i- 'he '-.'-i-tance oi the iialvaiiomet er (it i> necessary to kiio\\ md ,( internal resistance oi the balterv is so small in DYNAMIC' ELECTRICITY 229 The standard resistances used in the foregoing tests are obtained by the use of a resistance box. It is necessary to take precautions to secure joints as free from resistance as possible or the results will be vitiated. The ends of the wires should be scraped free from oxid or grease, and where delicate measurements are attempted, the different contacts should be made by dipping the ends of the two wires into the .same cup of mercury. Measuring Resistance With a Voltmeter. The apparatus required are a standard resistance, any source of electricity, and a voltmeter. First, with the current passing through the standard resistance, the voltmeter reads X, showing a voltage drop of X, or a difference of X volts between the two terminals of the known resistance. Then the same test applied to the unknown resistance shows a voltage drop of Y. The resistances are inversely proportional to the voltage drops. Measuring Resistance by Difference in Potential. This is a method which is delicate enough for testing the resistance even of short lengths of wire. It depends upon the fact that there is a difference in poten- tial between any two points of an electric circuit. And if two sepa- rate sets of points are tested along the same circuit, the two differ- ences in potential will be directly proportional to the resistance in the portions of the circuit between one pair of points and the resistance be- tween the other pair. Figure 168 shows the arrangement of an apparatus K Fig. 168. Measuring resistance by testing difference in potential. for making this test. G is a sensitive 1 galvanometer, a mirror galvano- meter, for example, with a high resistance as compared with the resist- ance which is to be tested. K is a constant current battery, such as several Daniell cells, and K is a key by means of which the circuit is closed or opened. R~ is the resistance to be measured, and the con- nection at either end may be made us in the diagram, by means of a mercury cup, or the Avire may be soldered to the other wires. R' is a standard variable resistance 1 , such as a 100 cm. of German-silver wire of a certain size, with a known resistance per centimeter. There is a very perfect electric connection between the two resistances. A double pole switch, not shown in the diagram, makes either the connection shown by the heavy lines in the diagram, or that shown by the dotted lines. In the former case the galvanometer is in shunt to the standard resistance R'. and in the latter case to the unknown resistance R 2 . R 1 is to be varied until, as we turn the switch, making alternately one connection and then the other, the same amount of deflection is pro- duced. Then R- -- R'. In other words, the resistance utilized at R' indicates exactly the resistance of the object which was to be tested. The adjustment may be made by varying the length of the wire which is to be tested if it is a wire, and in such shape that a sliding contact mav be had with it. The original 100 cm. of the standard resistance 230 MKDK'AL ELKCTRICITY AM) KoNTCKN RAYS wire is unvaried, and we find how many inches of the unknown wire have a resistance 1 equal to that of 100 inches of the standard wire. From this it is easy to calculate the resistance in ohms of any desired length of the wire under test. This method, l>y means of comparative difference in potential, is adapted to measuring the resistance of a short wire, or such a resistance as occur- at the contact between the brushes and the commutator section in a motor or a dynamo. Generally speaking, the resistance of different physiologic tissues and fluids is so great as not to be conveniently measured by this method. Measurement of Resistance by Direct Application of Ohm's Law. With any suitable source of potential, an amperemeter in series with the resistance to be tested and a very high resistance voltmeter in shunt to the resistance to be tested. By Ohm's law the unknown resistance is equal to the voltage divided by the amperage. Measurement of Resistance by Wheatstone's Bridge. This is on a very similar principle to that of the measurement of the electro- motive force by Lumsden's method of opposed electromotive forces. The diagram (Fig. 1(> ( .)> shows the general arrangement. One of the wires from a constant current battery, K, divides into two paths, A and H. havimr fixed resistances. The other wire from the battery divides into two paths, one of which -is a variable standard resistance, K 1 : and nwn resistance. II-. which is to be measured. A to a wire ln>m H 1 at the point I in the diagram. and a wire from H to one from R 2 at '2. Between the points 1 and 2 is a cross wire with a galvanometer, G. The current being turned on, there will be an electromotive force at 1, tending to send a current through the galvanometer toward 2; and at 2 there will be an electromotive force 'ing to send a current toward 1. fixed resistances and the vari- able standard resistance are regu- lated with reference to the resist- ance to be measured, so that the galvanometer -hows no deflection. \\hen this is the case, it is capable ot demonstration that the following U : : R 1 : It 2 . sides of the \ M ften, lire are en nit; Its re-i.-t aiice until the galvanometi i multiplying the value of I! 1 by Id. Kill, or K )()(), as the case may be. tli'' other li;ml. the unknown resistance may be so -mall that it will make A in. Kill, 01- KMMI times the value of I',. In that mid the value of IJ 1 . this value is to be divided by 10, if I! bears the same relation to ]>' that P> bear- to \-\. r condition may occur. It may not be practicable to \act balance, shown by the ab-ence of deflection in the DYNAMIC ELECTRICITY 231 galvanometer. The amounts of deflection with the nearest available values of R 2 above and below the true value form the basis for the calculation of the small fraction to be added to or subtracted from the nearest available trial resistance. The electric bridge or balance is made up in different forms, and in some there is a slight modification of the theoretic combination of parts, but they all depend upon the same principle': that equal opposed electro- motive forces produce no deflection in a galvanometer. The equality Fiji. 170. Drop in potential along a uniform resistance proportional to distance between two poles of a battery. The Wheatstone bridge equivalent. of the electromotive forces at the points from which the galvanometer circuit is derived may be illustrated by the diagrams (Figs. 1(59 and 170). Figure 170 shows a difference of five volts in potential between the point marked Cu-f- at the positive end of the bridge, and the point marked Zn at the negative end of the bridge. Representing electro- motive force as height, we should have Zn at the zero level, and Cu-f- at a height of five units (representing ohms). The line joining these two points represents resistance, and the point P has 50 ohms between i#. 171. Another example of the conditions in Fig. !(>!) it and Zn , and 1200 ohms between it and Cu . In other words, P is a point along the circuit separated from Zn by only one-twenty- fifth as much resistance as there is between ( 'u and Zn--. According to very well-established principles, the difference in potential between P and Zn is only one-t wenty-fift li as much as that between Cu and Zn . The electromotive 1 force 1 at P is, therefore, correctly represented by a height of 0.2 unit (equivalent to 0.2 volt). 2'.}'2 MKDH'AL KLKriKKITY AND KOXTUEN KAYS Turnim: now to Fig. 171. we find the same potential at Cu+ 'five volts) and that the resiMance let\veen I" and Zn (200 ohms) is one-twenty-tifth that of Cu + <>r <*- ohm. There 'is the siine potential at 1* and I" when the four resistances hear the proper relation- to each other, and having the same potential no tlow of current occurs between P and 1". Fig. 172. Student's resistance box. The Resistance Box. The fixed and variable resistances employed in te-tim: electromotive force or resistance are usually obtained from a h"X con: ainim: several coils of wire having different standard resist- ances varying from 0.1 ohm to perhaps 10. 000 ohms. In some cast's, the different resistances are introduced into the circuit by pushing a pliiii into a hole, and in other cases it is by pulling a ])lu.< out of a hole, and in still other cases 'here an- sliding contacts by which the resistance is changed. These resistance coils, of course, have a tendency to heat up, but this is not dangerous, because the current i> usually a small one obtained from a few l)amcll cells and measured in milliamperes rather than in amperes, and it is turned oil A resistance coil of looo ohms miiiht consist of DYNAMIC ELECTRICITY The resistance of German silver wire is about l^.o times that of copper wire of the same size. Electric Conductivity of Solids. Metals and other good conduc- tors transmit the current without evident change in their physical or cliemic constitution, and at the 1 same velocity as that of light. All sub- stances, however, present 9), and the other galvanometer in the cross circuit of the bridge. The resistance of the unknown galvanometer with or with- out a shunt is then tested as if it were any other resistance. Thomson's (Lord Kayleigh's) mctlnxl is useful when there is no other galvanometer available. A Wheatstone bridge is used (Fig. 174), and the galvanometer to be tested is placed in the ordinary position of the unknown resistance. At the place upon the cross circuit where a galvanometer is ordinarily placed there is none, but instead there i- a key for opening and closing this cross circuit. A and B are fixed resistances, and H 1 is varied until the deflection shown by the a!- vanometer is the same whether the cross circuit is closed or open. 234 MEDICAL ELKrTHICITY AND RONTGEN KAYS Then A R 1 B (I and (i -K 1 This method has the advantage tha: it is independent of the internal resistance of the battery. One wire from the battery should to the junction between the two lowest resistances, and the other wire to the junction between the two highest resistances. To Measure the Internal Resist- ance of a. Battery. The simplest and readiest method is illustrated in Figs. 175 and 176. The battery has two short heavy copper wires, and the galvanometer is shunted by a short thick copper wire, so that the resistance of the conducting cords (is . . . and- --, the joint resistance of Lr + S the galvanometer and its shunt, may be neglected. These resistances are to be very small in comparison with the internal resistance of the battery. The current is turned on. and the deflection of the galvanometer is noted. Then a resistance is introduced at R. and is varied until the galvanometer indicates only half as strong a current as before. Since 1 the current is onlv half as strong, the resistance must have been doubled. Therefore / (the battery resistance) -fll = '2 r. And/' = R. I7. r > ;IIH] 17). - Mc:i.-uriiiK internal resistance of a battery. Another -imple method is described on page 5)0. Testing Electrostatic Capacity. The static charge on an insulated ductor may be measured by discharging it through a ballistic gal- ometer. The latter is any galvanometer in which the movable part eavy enough to cause a series of pendulum oscillations in consequence '' momentary di-<-harge. Such an instrument must be graduated experiment with -tandard quantities of electricity, and this is done di-chartring known capacities charged to known potentials through it. Measurement of Electric Capacity. This may be done by ruing the bod', to a known potential, and then measuring the amount electricity by discharging i' through a ballistic galvanometer. 1 A certain amount of electricity may charire a body of large capacity '> low potential, and have very different properties (notably in that roduces no noise or -hock when di KOXTliKX HAYS 1 0.00 IS I 1 :; O.OOhS (I. IIDlS ' 0.00 IS OOOlb = 0.0001) microfarad. Ttxliini tin' Cn /xicili/ ni' a Condenser />// Direct DixcJmrgc. This is a .-imple method which vields approximate results. It requires the use (if a mirror galvanometer or a sensitive astatic galvanometer, and of a .-tandard condenser ot' known capacity. (',. A standard condenser Fiir. 177 1 is a necessarv pail of anv outfit for making tests of electric Kit:. 1(7. Standard condenser. capacity. Snr-h n standard capacity of ^ microfarad may contain 1'Ji n i xjiiare inches of tin-foil in small sheets separated by paraffin paper. The same bat tery is used to charge first the standard condenser, and 1 hen i he condenser whose capacit y is to be measured. The standard ondenser is discharged through the galvanometer, and the amount of defied ion, d,, is noted. 'I' hen 1 he condenser with an unknown capacity, ( '. i- discharged through the galvanometer, and its deflection, d 2 , i.- noted. Then r, : C, : : d, : ,1, 7 >!,,,: .-.,.(,'. i /,',: //, it//,'.-') M< /find of Ten/ing fJie Cfipaeitft of Condensers mat Cniidiictni:--.- The capacity to be tested for elect rot herapen tic purpo;-es i:,;:-. In- that of the secondary winding of an .r-ray coil or er. 7 /' A f>i>tirtifn.-- ff(ffnii-(d (Fig. ITS). P> is a battery of about ten Daniel! 01 other coji.-taiil voltaic cells. This must be well insulated from the gfounrl, M< \ve)] as between its two opposite charges. A ' /' is a l.i \ ' e;ms of whicli the circuit is made or broken close to one pole of t he ! i;it t , A' r is n key by the circuit is made or broken between the battery, and one end o! the coil of wire whose capacity i.s to l)e tested. The ial t'-; i.- marked , ,,'/. DYNAMIC ELECTRICITY Coil in the diagram has the other end of its wire free. C 2 is the capacity of the coil expressed in microfarads. AY// :i makes or breaks the circuit at the point where a wire lends from the battery to one electrode of the standard condenser, whose capacity is C' 1 expressed in microfarads, and whose other electrode is grounded. From a point between the battery and the standard condenser a side line crosses to the earth through R 1 , which is a variable resistance. From a similar point on the cir- cuit from the battery to the coil a side line passes to earth through R 2 . which is a fixed resistance. (!, the galvanometer, is on a line connected at one end with the junction of these two resistances, at the point where they are fastened to a ground wire, and at the other end with the circuit between the standard condenser and the coil. o^^d AY//-"' makes and breaks the gal- Fi. 178. Testing the capacity of a coil. vanometer circuit. The test is made ax folio irx: 1. Close Av// 1 , then V 1 and V 2 may be the potentials at the points of junction of the battery wires with the resistances R 1 and R 2 leading to earth. The current is the same through the battery and through both resistances, since these are in series. The voltage, therefore, must be proportional to the resistance, and we have V 1 : V 2 : : R 1 : R-'. 2. While Av// 1 i still closed, close Av// 2 and Av// :! simultaneously for a fixed time, charging both the capacities. The standard con- denser C 1 is charged to a potential of V. while the capacity C 2 to be measured is charged to a potential of V 2 . A'//-"' and Av// 1 which lead from the free extremity of the coil to the condenser, have been open during th.'s time, and the proximal electrode of the standard condenser has been connected only with the negative pole of the battery. The capacity to be measured has been connected only with the positive pole of the battery. The proximal armature of the standard condenser and the capacity to be measured are. there- fore, charge* 1 with negative and positive electricity respectively. The quantity of negative electricity received by C' H Q 1 Y'C 1 . while the amount of positive electricity received by C 2 is (,)- \ -('-'. o. Open Av//' and Av// :! . cutting off all connection with the battery. Close Av//' 1 . allowing the positive and negative charges of C 2 and C 1 to mix. Their potentials are. of course, immediately equalized, and if the quantities are equal, both charges are neutralized. Open Av//' to test this. The occurrence of a deflection indicates an excess either ot positive or negative electricity in the combined capacities, and another trial must be made with another value, to the variable resistance I! 1 . Tin's is repeated until a complete equality and neutralization of the charges in the two capacities are indicated bv the absence of deflection in the galvanometer. We now have the factors for the calculation oi the unknown resistance. These factors are the resistances of the two JliS MI.DK AI. I.I.i:( 1 UK II 1 AND KOXTOKN HAYS ,.; ;';. >hunts determining tlir voltages required to charge the standard . ilic iiiikiu'\vii capacity \viili the same quantity <>i elee- . Vn h d ric capacity i.- like a compressed air-tank - just so much H forced into it ami will completely till or charge il at a , ure; !'ii' t'mir times as much can he lorced in and will he -e it at twice that pressure. \o less amount I produci t he specified pressure in the condenser. ['he i< >lli 'wint: i- 1 he calculal ion : \ t \" '('-'. ['he i|Uaiitities of electricity in the two capacities . ,,;.'.. And from this the following proportion is obtained: n mat - V- : V : : R- : !{'. i; 2 : K' : : ( '' : ( "-'. Mini t'rmn tl / . There is re niher methods of measuring the capacity of condensers IT i . . :-. h it this one is accurate and readily available for labra- .. \ -ei n| Leydell jars of eijual capacity connecteil in jiarallel has a iv fnimd l>y multiplying the capacity of one I.eyden ':.' numher of jar.-. '1 he same jars connected m .-cries have a ,:,' ; :'.'. which is found 1 iy dividing the capacit \" of one jar (>: n-i dii'fi ri :.' ci ml iinat ions may I" 1 made corri'sjKindinii to the ---:. alni -erie--mull ijile arrangement of voltaic cells in a \> .'''].. The.-i' inve anv de.-irei 1 capacit v, lai'u'e or small, if t here are M r o| Ley i Icn jar.- a\'allal ile. -'-''' '// en/nil n*< r is exactly analo^oii< to a l.e\'den jar numlier of sijiiare inches of metal foil, and separated :i iekne>s of ;_ r la->. I'ut a liat ula.-.- plate considerably ires i~ used in. -tead of a jar, and t lie di>t al surfaces - are coven-d by irlass plate- \vliich extend beyond the : are -o Me red to i he dielect ric u'la-- plat e by a cement '}:< -ame composition as the u'l;'.--. I he condenser In ' ' of tilass. containing in it- interior t wo metal each other bv a certain thickness of si;la>s. At i hi periphe|-y ni t he i:la-- I here are metallic n m- iri . Tin- met hoii of const met \, ,n j ti'i'\'ent s ''.'.' e- place all arolilld t he ei l wliei'e t he conl act I !n - 1 1 ai'i n ' la I in ' n ;-- 'j. ; \ acua, ' '. i if elect ricit v. and do not tend i" i I i inches in diameter; while the complete condenser with an ebonite top and bottom and metal binding-posts forms a disk about 12 inches in diameter and about 1 j indies thick. Two or more of these condensers can be made into a thicker disk, and may be connected in parallel or in series or in a combination of the two wavs. This connection is a remarkably simple matter, assuming that the condensers are all placed one on top of the other; the binding-posts of the top armatures in the various couples may be turned toward one side and those of the lower armatures turned toward t he oppo.-ite ,-ide \ Fig. 17'. I ). A .-in i pie metallic connection binds together all the connections on one side, ami forms one pole of a condenser having a capacity equal to the sum of the capacities of all the separate couples, while all the lower plates are bound Fig. 179. Rochofort's monolith condenser. Usual p:ir:illol cnmicction. together in the same way to form the opposite pole. These condensers can be equally well connected up in series. Turn the binding-posts so that in the connection from the upper plate in the first condenser shall be toward the right, and from its lower plate to the left: and that from the upper plate of the second condenser to the left, and from it- lower plate to the right. The connection is made from the lower plate of the first to the upper plate of the .second couple at the left of the combined condenser: and from the lower plate of the second couple to the upper plate of the third couple (Fig. ISO). Levden jars or Rochofort's monolith condensers are used for the extremely high-tension charges of t he st at ic machine and high-frequency apparatus, because glass forms a highly resisting dielectric, and is not so VSSS/S, '- :::::::\Kubb 1ST cou/>/e Zc/ctwp/e ff/ass V. >///.',: Jd coufi/e y . ' 1 A/ liable to puncture as paper, wax. or mica, and is treer trom imper- fections. The glass wall of a Levden jar or the layer of glass between the armatures in the monolith condense!' will resist the electric ten-ion required to produce a (i-inch .-park through the air. but if a puncture doe- occur, the discharge melts a path for itself through the glass, and this usually destroys the condenser. (Miter dielectric- sometimes used for high-tension condensers are '. and coinpressed air or gases. There are two chief requirements in she case of a non-conduct i; -' laver used as the dielectric of a cimdensi r for high-tension elect -mi . tin [i up as litrhtlv and compactly as possible. Kadi armature ni' t in -foil with a 1 1 it al surface of about 7-"> square yards I - s!u < !- nt' liii-inil arc usually >eparated from each ni in'T i in I paper or by sheets of mica. There is not the as in the case of hijjh-t ension currents. The ire> ainl dielectric are consolidated under heat and !:--.:. -ii a- to form a -"lid Muck which may lie concealed in the base > -. parate i rom n. Such a condenser usually has : in surface or parallel, so ihal 1 he fir-t and the :'i!t, <.. metal -heei> project at one end. and are all ith one electrode, and really form a single armature "U-l' lar^e surface. 'I he older set of metal sheds, the c.. project hey ond t he ot her edge of t he paraffin -. ami ; i l>y a single electrode to form another single ' UP '! very la ri_ r e surface. i IT. 1 M . A, -hov- in a diagram mat ic way the const rue lion of such a -er. \v!t!i the two opposite sets of metal sheets interlacing and : prevent in !. as in i he diagram, but are pinched together !> I .'.' re are many more of the different layers than vised by the author as a convenient dia- ilion Ml a conden.-er. ( Mie set of metal sheets i'^ e p-i|e o| t he elect ric general or interlace with ; po-ii i\'e pole. The dielectric separating the ^ represented by the space between them in ' ' ' 'I he familiar process of '. 1 s -'. where i me elect n >de (from - tolleiied to I l,e positive pole iher eleet fode M'fom t he external armature 1 ' ' i\ pole of the static b. Mil ei mi lit ii iii -In iwn in l he diagram '"'' ; ' . and it- outer . iv. "I I he many-leaver] condenser I s ->. \ lieel ion i \]'-1 - bet ween 1 : ' Hie i li c1 fode of i he con- ' 'i neural i'.'e elect ficit y. .' tl po-it ive , left ficit V b\' DYNAMIC KLKCTKHITY 241 direct connection with the positive pole of the battery. Xo current can flow under the conditions sho\vn in this diagram, since the two armatures are separated by a non-conducting dielectric and the circuit, is not completed in any other way. If the buttery should suddenly give out, the condenser would discharge itself through the conducting wires and through the electrodes, and the liquid electrolyte of the battery. The direction of the current, from the condenser would be Fiji. 1S2. Charging a Leyden jar from a static machine. Fin. {. Charging a rondcn.-or from a voltaic battorv. from its positive electrode through the conductor, through the batten', and through the other conducting cord to the negative electrode of the condenser. The path thus described corresponds exactly with the discharging rod by which a J.eyden jar may be discharged. Fig. 1S4 shows how such a metal rod, held by an insulated handle, may be applied to the two electrodes of a Leyden jar, and allow the current to ilow between the two until the positive and negative charges are neutralized. Here as well as elsewhere the direction taken by the positive charge is called the direction of the current. "V " Fiff. 1S4. -Disehartnn" a I.cydcn liattcr\ cm-nit and liccnmiim charged when jar !>y means of a discharging rod an insulated nan Figure IS") shows a similar case to thai in Fig. IS.",, except that there is an interrupter at I, which is open in this diagram, but which, when closed, forms a complete circuit for the battery. The interrupter beint: open, there is no current flowing, but I he positive and negative plates of the condenser are charged with electricity. ('losinii' the interrupter as in Fiu. 1st'.. ;) double effect is produced. First, the condenser become- discharged by the pa->auv of a current from its positive armature through a -hurt conducting cord to the it; MKI>h AI. Kl.Ki TKIc II V AND KoNTt.KN HAYS hack through tlir other slmrt conducting conl ;,, ;.. ulc Hi" the condenser. Second, a current flows iTOlll ;., voltaic battery through tin- cunductiiig cord to ii nee through the other conducting cord to the pule ( .f the liattery, and through the liijiiid electrolyte to the 1,-. As 1 terrupter is dosed the battery current [he i-i uidetiser remain.- uncharged. :_'. 1 S 7. -Condenser in shunt to the pri- mary wire (if an induction coil. ( 'oinpleti t and di-charui' of condenser. iw. the interrupter opens as in Fig. IS."), the battery current - fur a -hurt time, not making a complete circuit, but flowing condenser until it is fully charged. Then things remain as 1 in the fir-i reference to Fig. is."), until the interrupter is again closed. Tin /,'//'*('/ of a Condenser I /><>// the I'rin/ii/i/ Current of '' -d i >r ' \t ra current . pr< iduced in the DYNAMIC KLKCTKHITY 243 primary coil by self-induction. This extra current has two deleterious effects. First, it is of high tension, and sparks to a disagreeable and injurious effect across the open interrupter; and, second, it forms a sort of continuation of the primary current, which should cease quite promptly in order to induce, at its break, the best possible current in the secondary coil. The beneficial action of the condenser is in the correction of the.-e two deleterious effects of the extra cm-rent in the primarv coil. This extra current rushes first into the condenser and charges its manv- leaved armatures, one with positive and the other with negative electricity, and the capacity of the condenser is calculated to be sufficient to receive all the current which would otherwise form a spark across the open interrupter. l>y the time the condenser is fully charged with this high-tension electricity the high electromotive force of the extra current in the primary coil has disappeared. The condenser is now fully charged at a higher tension than the electromotive force of the battery, and it at once becomes discharged. It sends a current from its positive electrode through the conducting cord, the battery, and 1 1n- other conducting cord to the negative electrode of the condenser. Tin; interrupter is open during this time, which is very short. The discharge from the condenser also surges into the primary wire when it is in the op- posite direction to the battery current, and its effect on the current in the primary coil is not only to bring the primary current to a stop almost as soon as the interrupter has opened, but. in addition, to produce a countercurrcnt in the primary coil. The latter has an inductive effect on the secondary coil, augmenting the effect of the cessation of the primary current. The break current or the secondary current induced by the cessation of the primary current and flowing in the same direction as the primary current is of greater strength, and has more important uses than the make current. The condenser, therefore, has great value in every case in which the extra current is a disturbing factor in depriving the coil of the effect of a prompt, and complete cessation of the primary current at the time that the interrupter is opened. Cases in which an Induction Coil AYr/////T.s' a Condenser. Coils usinira heavy primary current, 6 or more amperes, and a mechanic interrupter, always require a condenser. .r-Ray coils, therefore, except those with a liquid interrupter, require a condenser. ( v See page 14S.) Cases in which an Induction Coil l)< x \ <>f Required Condrtifn r. Coils which are intended to cany only a small primary current do not usually need a condenser, although they are usually made with mechanic interrupters. Faradic coils are in this class. The Y\ ehnelt and Caldwell-Simon interrupters produce a quality of break in the primary current which yields an excellent inductive effect without a condenser. The familiar experiment of interrupting the flow of the primary current by cutting the wire with a bullet from a rifle produces so rapid and complete a break of the primary current that the condenser proves to be unnecessary. The Potential and Capacity of a /.< <'/<>/ Jar. An insulated metal ball (Fig. LS9, A"), connected with the positive pole of a static machine, will be charged to the same potential or the same number of vit- as that pole of the machine, and it has been established by experiment that the quantity of electricity which i' \vill receive or its capacity at that potential is q=-VR, \l being the i is of the sphere A. i:i.i:eTRierry AND RONTCEN HAYS h" thi- -phere he surrounded 1 .y ;in (Eternal conducting shell, B, ted from the -phere A by a layer of air or other dielectric sub- : connected with the earth, the static machine still continuing to maintain a potential of V. the inner positive sphere will at first induce 4 a charge in the outer shell which will attract negative electricity into the shell from the earth, and repel posi- tive electricrv from it into the earth. The negative charge upon the shell will in turn act upon the inner sphere A. and attract into it a larger positive charge than it could have received without this influence. This is the well-known principle of the condenser. Two conductors separated by a non-conducting di'-lectric have an increased capacity for elec- tricity, and if charged to the original potential V. each will contain a quantity of electricity < ^ and t{. which is greater than cither could have been made to receive I'roin the same source of potential when by itself. The potential y of the inner -phere is equal to _, . and that of the J L H ;i lesser potential, the latter var\'ing as the quantity divided bv adius. : : lential, \", of the whole jar is made up of two parts, the -; ive poti nt i;d of the inner sphere. \" : J i and the negative . \' 1 . The combined ]>otential < > QfR 1 - Hi \' R P 1 R>' N RR> " r( ^U'-R; ve found an e\]>ression for the difference in potential ." : and inner coat.- of a Leyden jar of complete spheric s of whose dielectric is R 1 H. J! 1 is the radius of ire. , : ; I! the radius of the inner sphere, and (,). the ; i i- found as a positive charge upon the - a negative charge upon the outer armature. ' : . to consist of i\vo ci,mplete concentric spheres. y R R ! I /. 1 ss . lie charge is O , and if li . t being the '1 III 1'nli nt nil nj n ('ninij d ( '<>n. :;.0i:5 to '.).2.'^ Petroleum. 2.(Ki to 12.07 Kbonitc. 2.284 Hisnlphid of carbon. LSI Gutta-percha, 2.402 Vacuum, o.'.i'.i'.it Uoltzmunn) India-rubber, 2.220 to 2.497 Hydro-mi. O.'.i'.i'.iT Boltxmaim - Paraffin (solid), 1 1HK50 Carbonic-arid gas, l.non:! Uolt/munn Shellac, 2.74 Carbonic-acid <:a>. l.ooos . \yrton and 1'crry i Sulphur, 2.58 Sulphur dioxid. 1.00.'>7 The experiment of the dissected Leyden jai % shows that the two opposite charges are held upon the surface of the glass, even if the outer metal coat or armature is removed and freely handled, and the same thing is subsequently done with the inner armature. Certainly no charge remains on the metal, but the moment the metal coals are replaced, the Leyden jar may he discharged bv touching both armatures at the same time. 4' he armatures and thedischarging md form a met al conductor from the charge upon one surface of the glass to that upon the other surface. Air forms an excellent dielect ric for a condenser, and is used for that purpose in some types of high-frequency apparatus. Its ntilitv i< greatlv increased when under pressure, since air then becomes a better insulator, and disruptive discharges and efHuvia are prevented. I'l'dcficd I'lilii'/ />t ' Cotnli />.-> :.-. I' \ - Idom that any practical use is made of the experiment in which ;i i.eydeli jar may receive a chariie and then be disconnected from the tTenerator and retain it.- charge until a conducting path is brought near ' ' to both armatures to permit i it a disrupt ive disdia rge. When this disrupt ive discharge tal e- place over the sreatest stri distance, t h(> condense] 1 lose- all bin of its charire. !!.. :v- charge mav be discharged in the sami -av 1>\ bringing iln discharging Jit. j-,,,1 nearer ti the two armatures. And aiiain there remains a small | llt .. \ ><-rie> ni' sparks may. t herei'ure. be obtained until finally ; : ni.-l be placed in actual contact with both arnia- .;e ; he ci mdenser. > /;/, >, // ,. and <><>t "j a (.'nndrnser. The function of ; ; ,.,,n ; -- L- ,- . ll\ to act as a reservoir into which electricity is pi ci 1,1- . '-.: : a.-ed pressure in a circuit, and from whicli it iii again at periods of low pressure. The double bulb nl a i.- .: in -'. rin lie or atomi/er furnishes a partial analogy. 1-. ':...- , - :nv oi tiie hand exerted in squeezing the first bulb - ; , -, , . ' illi to expand and receive a portion of the air or ,-ise be forced through the tube. When the .-;;; > relaxed, the pressure thus produced in the second bulb ; - iir or liquid into t he tube again, and there are generally valves it in ':.. direction of the current flow. The object in the case -vrii.iii i- to secure a uniform instead <>f a pulsatile flow, and this i-iii-i] by suital)le regulation of the size and elasticity of the lib. I: must not completely empty itself before the next : t he tii'.-t bulb. Tin n-er in an electric apparatus receives its charge under -MIIV ju.-l like the second bulb of a syringe, but it gives up the mre promptly -in fact, almost instantaneously ;.!-:. in tension in the circuit. The condense! 1 becomes fore the period nf lo\v pressure is finished, and the tension ; : . i;oi rendered uniform. Another difference is that the . o] the interrupter stops the current in the original , irrent due to the high pressure in the condenser and : -- ire ii the circuit is compelled to follow a direction the M!H original current . Thus the charge during a period :' I i i-hes into the lariie capacity and insignificant resist- : user only to surge out again during a period of low ' ' ' 'ij'cu it '.:.'' ''' - n| 'In- condenser with the circuit are not made and - operation. ] lie condenser terminals may even be ' tin 1 battery circuit. The making and breaking ol in 'i rruptef do not occur on any line leading to or from ' rnipter and the condenser are in shunt to i'v pa->es throiiirli the primary coil and the ''' ' i.- closed, but has to take the other path -er -shell the interni])ter is opened and the ; iced in t he primary coil. The Capacity of Circuits, \\liile condensers have very great ' - I'V cond (c| iir i it i led rn'it y has a cert am - a prepa rat i< >n fi >r t he t ransmission of tension current - in t he case . where an impulse requires an t he wire. Tlii- limits t he They are m >i in.-t ant anei .us. ' lie kcv and thus n umect ing : ". uniformly as long as wire assumes t he con- p"t i n t ial. and has a 1 emlencv ' h ' ifdinarilv a \-ailable DYNAMIC KLK< TKIdTY is at a distal point, and so all the current commonly (lows in that direc- tion, but there is the same pressure in all directions. There does not appear to bo anything which could be called electric momentum. It' a current continues to flow in a given direction, it is because of a continued pressure or difference in potential, and the current will not continue to flow for an instant at any point in a direction contrarv to the pressure at that point. Take a long wire (Fig. 100) starting from the positive pole of a battery whose negative pole is grounded, let this wire have a key for turning the current on and off near the battery, and let it run to a telegraph receiver near the other end of the line and beyond that be grounded. When the key is tinned, a current passes through the. I'ijz. 100. Battery and telegraph wire illu-tratiuc; capacity of the latter. wire and telegraph instrument to the ground, and, of course, re through the ground to the negative polo of the- battery. If the key is lifted and the electromotive force of the battery is cut off from the wire, there is no piling up of electricity in the distal part of the wire, leaving no charge in the proximal part, as would tend to be the case if water were Mowing rapidly through an inclined tube and a stop-cock were turned at the top (K' 1 , Fig. 101). In the latter case the inertia of the water would create a minus pressure near the stop-cock K 1 . Nothing analogous occurs in the case of electricity. Looking at the other end of the wire, suppose the key near the battery is kept turned on all the time, but there is a key near the telegraph receiver. If this key is Fi. 191. Inertia of water flowing t lii-onirh an iiteline'1 tut turned off, there is ordinarily m> continued onward pressure of elec- tricity, as there would be of water in Fiir. 101 if the stop-cock 1\- at the lower end of the inclined tube were turned off. In the case of water, the motion into the lowest part of the tube would continue in spite of a developing adverse pressure. This pressure is mvat enough sometimes momentarily to carry the water in the stand-pipe. P. to a higher level than that of the original reservoir. In the hydraulic ram the inertia of a body of water falling through a \ertical pipe, and arrested at tiie bottom at intervals, is used automatically to compress air and force water to :l much higher level than that of the water in the reservoir. A liquid or anv solid body in motion acquires a momentum which will produce a certain pressure at the point of impact if it be suddenly Jl^ Mi.mt AI. 1.1.1:1 nucri v AND KONTCKN HAYS arrested by some nh-t acle. The preure is momentary, and is very i!ir \\. mill ni' tin- moving body and ils velocity are both great. >n ; ; j 'plied as to impart t lie saint- velocity to an equal mass or to impart a greater velocity to a smaller mass or a less velocity to a greater mass of mat ter. AM eleci ric current tlowini: through a short straight wire and suddenly arrested produces no such etTect. nr should we expect it to when we inderahle nature and the double directional character uiges in a material path which constitute a so-called electric ' . The < \ i ra current with its spark at the interrupter, when the primary <' .' : coil is broken, does not indicate the existence of c! . t ric n on i ntum. 1 'Hi i> produced hy indue I ion. 1 : , ction iii the case of the Atlantic cable results in its nth second before i he first trace of a signal is received at nd. and the full suvngth of the current not being registered live >eciiiids later. An expert operator can .send about twenty a iuute. There are some most wonderful facts in regard to trie transmission, one being that a voltaic cell consisting of a per- c i--! i-d with dilute acid into which a zinc rod is dipped can irnal across the Atlantic. Much stronger currents, of course. an l-Ualh empli i\"ed. ELECTROLYSIS 1 his i- a rhemic change of decomposition which often takes place i' ' which a current of electricity passes. The products of electric decomposition are called ion*. Cations or :>penr at the negative electrode or cdtJioth . and >-itive electrode or (n/ixlr. Fig. 192 shows the classic experiment of passing a current of electricity Hirough water, slightly acidulated to render it a L r v t he 241) electricity which flows through an apparatus by not ing the amount of chemic decomposition produced. The simple product which is measured may be a gas, as in the case of the water voltameter, or it mav be a metallic element, as in the case of the silver voltameter. In this instrument the positive electrode is of silver, the electrolyte a solution of silver nitrate of a standard strength, and the negative electrode a sheet of platinum. During the passage of the current metallic silver is deposited as a silver-plating upon the negative platinum electrode, and dissolved away from the positive silver electrode. The platinum having been accurately weighed before and after use, its increase in weight shows the amount of silver which has been deposited or separated from its combination with nitric acid. Within reasonable limits the amount of silver so deposited indicates t he quant it v of elect ricit v which has flowed through the meter, /. r.. the number of coulombs irrespect ive of the rate of flow. One coulomb of elect ricit v will deposit 0.001 Ms gram of silver. A current of 1 ampere is a current flowing at the rate of 1 coulomb per second, and will deposit 0.001 MS gram of silver per second. This is at the rale of about 1 grain a minute (English weight ). A current of 1 milliampere would require a thousand seconds to deposit the same 0.001MS gram of silver. The copper voltameter has two copper electrodes and a 10 per cent, cupric sulphate solution as an electrolyte. It is accurate to within a fraction of 1 per cent., and was formerly extensively used in measuring the electric-light current and determining the amount to be charged by the com pan} 7 for the use of the current. A voltameter gives correct readings only with a direct current and with a certain strength of current . In the case of the copper volt a meter, this corresponds to a current density of about 0.01 ampere per square centimeter of cathode. The voltameter is, for economy of power, placed in shunt, so that only a definite fraction of the current passes through it. The size of the cell and its electrodes varies somewhat with the strength of the current which is to be used, although a wide range may be obtained from a single voltameter by varying t he multiply- ing power of the shunt . In this way the same weight of copper deposited and, of course, the same quantity of electricity passed through the voltameter indicate the consumption of a large or a small amount of ."urrent, depending upon the shunt. The multiplying power of the latter must be known to make the voltameter ot any value at all. The voltameter finds its chief utility in the case of a direct current having always approximately the same strength or amperage and the same potential or voltage when it is being used at all. I he volta- meter gives the total quantity of elect ricit v which has flowed since the last reading was made, and gives a total of all the short or long periods that a stronger or a weaker current has beer, turned on. An amperemeter would not give thn inlonnation unles- there were some one t here to note the strengt h of I he current, and how long it was 1 1 e the average st t'engt h of the >i had flowed. The meters in commercial use at the present time are mostly based upon the magnetic effect ofthecun ; are of the nature of duck w< >rk run bv an elect ric motor. 'I his has t lie advantage that it may be constructed to measure either alternai i - 01 direct currents, and 's readings are directlv visible upon a dial on the outside ol the meter. '2"i(l MKDIi'Al. KI.F.t 1 1U( ITY AND RONTGEN KAYS Reversible Electrolytic Cells. In practically every case when a lit : electricity ha> been passed throuiih an electrolyte, if the electrodes are disconnected from the battery and connected with a galvanometer, this instrument will be deflected. It will indicate the presence -.MI in the opposite direction to the battery current usly been flowing. This current is due to chemic L: place at the surface of the electrodes and in the electrolyte reverse of those previously produced by the battery tit. A Morale-cell or accumulator affords the best example of reversed "l'd compound:- at the elect rodes during the passage LMMIZ i'urn 1,1 and the cell, after disconnection from the charg- '.'-. acts in every respect like a most efficient voltaic cell. i cotinieri-li-ct roinot ive f,,rce of an electrolytic cell is present '., the pa a<_ r i' of the primary current through it. Two observa- - fact. A portable ./--ray outfit may be run by a ha rued from a dynamo operated by a belt from a -'tied upon a suitable support. A man has to work very ''p tin hicycle pedal- going and the dynamo revolving, and -'.'.- current flowing through the storage-cells against the ive force developed in t he hit ter. The power required - nl the bicycle while charging six cells at once is so ' ' can hardly keep at work more than fifteen minutes i hi ': be relieved by another man. Thus the work !"!' ten or twelve hours. Where the electric-light ' -ame amount of power is consumed. the coiintt-relect romot ive force present dur- ' ' : ni percept ibly decomposed into hydrogen ion of 11 or '_' volts is applied. A smaller en! to pass through an electrolyte, such as ' : acts as an ordinary conductor, and not plied elect romot ive force is greater than ' loi'ci. in-derated by the products formed at it , I'hi' p' iwer required t o send a weak ci induct i r i- ii' >t -uflicii'iit al.-i to gen- 1 'I mill I '. Volt s elect r> iinot ive f< irce. ' l\'e 1' irce i if an elect r< ilvt ic ',\'<' shall not only have a current ' m ic c ha 1 1 ijes apparent at -!!' to those which tend ; : will be produced there iiinect e/ ln/dr<>i. a univalent element with an atomic weight of l.OOs. will combine with S (/rtnns <>f nxi/ycn, a divalent substance, with an atomic weight of Hi, to form water. Or. lO.'J.Ui -:rams of lead, a divalent substance of an atomic weight of 20().ni2. may replace 1 gram of hydrouen in completely combining with X grams of oxygen. The gram equivalent of lead is, therefore, lo:i. l(i. Faraday's first and second laws are that tlu 1 same quantity of elect ricin equivalent of any .substance. be Oli.dOO coulombs, and is called :i .' _' .")_> Mi-:nn AI. i.i.i:< TKMITY AND KOXTCKN HAYS < >:. faraday is the ammmt of electricity required to liberate one cram equivalent of any substance, and is equal to 90,000 coulombs. 1- i- equal tn the amount of electricity carried l>y a current of 1 ampere I;, ',);. t'.no seconds, or twenty-six hours and fifty minutes. The following are the irra m equivalents, equal to the number of different substances liberated by 1 faraday, or 90,000 1 f liV.il l- ()t)S : .in o'.t.l 10 _>:'.. 0,">0 Ml, is. 070 Tin' . ii r icht-n ic equivalents of the same substances, or the number i ! >y 1 ct Mill mil i. are: 101.:; \ .j^ylo '' '" LOX10X10X10XIOX10X107 1S71.0 o 4 Cations are the hypothetic charged panicles which travel through the electrolyte in the direction of the current, and are liberated at the cathode: they include all the metals and hydrogen. An ions include chlorin, broinin, iodin, fhiorin, .\< ).,. S( >,. and acid radicles and < )H. Klectrolytes are otten aqueous solutions of salt.-, but some other substances are found to be decomposed, uniallv to a less degree. An atom of silver carries the same electric charge or transfers the same amount of electricity as an atom of hydrogen. Grotthuss' hypothesis of electrolysis is that the molecules of a dissolved compound form a chain, and that under the influence of the electromotive force they exchange partners in such a way as to leave a free atom of one substance at one end and of the other substance at the other. Thus in the electrolysis of hydrochloric acid the molecules form such a chain as this: (H('l) (H('l) (H('l) (HC1), but under the influence of the electric current this becomes H (C1H) (CUD (C1H) Cl. Clausius' Theory of Electrolysis. This is that salt molecules in solution occasionally dissociate into a positively and a negatively charged portion, i. c., positive and negative ions. The cations move in a general direction from the anode to the cathode, while the anions move in the opposite direction. Those ions which reach the respective electrodes give up their charge there, and also form a free mass of a simpler substance, either as a gas or as a metallic deposit, or as an acid radicle combining with the substance of the electrode, as the case may be. Xot all the cations or anions reach the respective electrodes. Very many of them encounter oppositely charged ions and become neutralized. Decomposition and recomposition of the molecules are continually going on, with a resulting uniform drift of oppositely charged ions toward the two electrodes. This dissociation, or the formation of ions, is not necessarily the result of the electric current, but is present whether or not there is any current. Their rnndntt, however, is a result of the electromotive force. The Electron Theory of Electricity. Observations upon elec- trolysis in liquids and upon the ionixation of gases show that the nega- tively charged particles in a gas are only , J nn the size of a hydrogen atom. Positively charged bodies as small as this are not known to occur, and so a theory has arisen t hat t here is only one kind of elect ricity. This is t he kind termed n< gatirc, purelv by convention, and it is assumed to exist in unit charges or atoms of electricity called electrons. A negatively charged body is one containing an excess ot electrons, a positively charged bodv. a deficit, and in a neutral body the electrons are in equilibrium. This theory, which is rapidly becoming the accepted one, regards electricity as consisting of material particle- a uTeat deal smaller than the atoms known in chemistry. Kadi elect nm carries a charge of about I .-'vt X 1()~"' coulombs. It requires OX 1 ( l "' ; electrons to carry one faraday of electricity. With univalent negative ions, such as chlorin. each charged atom or ion has one electron. This adds o.ooi to the mass or weight of the atom of chlorin. which is :!."). 1 (limes the weitrht of a _>;,l Mi:nn \i. KI.KI THICITY AND KONTCKN HAYS ;akes the chlorion weigh Ho. 401. The following nl ; , ill;; ;, - iiic ;-c ni' tlic svmbols that have been adopted for ,-xpn ~-j:n: ' aii atom of chlonn plus a negative charge equals i ivi .'Morii! inn: Cl Cl I-, , M Xa - vl- Xa signifies lhat an atom of *ii i\ e charge equals a sodion. <>r a positively charged ion. A positive charge subtracts the weight of an electron t nl an um-harged sodium atom. The weight added to ; [> in electrolysis or in a voltaic cell is exactly equal to ,1 from the oppositely charged atoms. \:: . ni i.- propounded in Iss? the theory that a salt whose solution I p.lyte becomes lariielv or in some cases completely dissociated -;;. ions of one siibst ance and negative ions of the ot her. This irs as the result of the chemic process of solution, and quire the application of an electromotive force, though the . njiverned h\- such a force if it is applied. In a voltaic cell, ii . ier; p.posit ive element or t he one which is dissolved by the acid charged ions of the metal are produced, while the plate itself e- an equal negative charge. The opposite charges produced in ,vav in thet" i elect rodes are the source of the electromotive force. Arrhenius' Theory.- This has to do with the solution pressure and osmotic pressure of substances, and their relation to the degree of I) elect p >lvl e. \ - ilutiou of sugar in water may be placed in a semiporous jar which -I'd except for its connection with a pressure guage, the jar being ; in an outer jar of water. The "semiporous" jar permits the :. I mi not of the dissolved sugar, through its pores. It ' : , ; . for example, hv taking an unglaxed porcelain jar filled |>hate of cop]iei- and placed in a jar containing a ->i im ferrocvanid. This results in co])per ferrocyanid : .:. the pores of the jar. which gives the jar the "semi- bove described. Any soluble substance has a \ pa rid :::.; occupy the whole of the solvent (the dissolving ,;'>! to a jar half full of a solution of sugar, the sugar themselves through the newly added water, the entire quantity of water will contain a sugar -tren\ the t eudeucy Hsi-ll thi niirh the lai'gest possible amount of "' [>ass t hrotiirh the wall of the jar, t he water the seiniporoiis jar and form a I he cm r;i nee iii water increases - P L'istep-d upon t he guage, and 1 his in re \s ati r mav enter. The final pressure attained is that which produces an equilibrium between the attraction impelling the water to enter the jar containing the sugar and t he mechanic pressure inside t he jar. The apparatus which has just been described is an osnwmrtir, the force exerted by a soluble substance in drawing the solvent dissolving liquid to itself is called the osmotic prasfiiirt of the substance. \"an't Hoi'f was the discoverer of the fact that substances in solution behave like gases, and generally are governed bv the same laws. Just as gas molecules distribute themselves uniformly throughout any space that is open to them, so the molecules of a soluble substance distribute themselves uniformly through all parts of the solvent. Boyle's law is that the volume of the same quantity of any gas varies inversely as the pressure is generally applicable to dissolved bodies. Their osmotic pressure usually varies inversely as the volume of liquid in which they are dissolved. Avogadro's law that under similar conditions of temperature and pressure equal, volumes of all c/axi'* cj niuhculf * is also generally true of dissolved substances. "Van't Hof'f noted, however, certain exceptions to the application of these two laws in the cases of soluble substances, and found that for any particular substance; there was a fixed and definite ratio between the observed osmotic pressure and the osmotic pressure calculated according to the laws of gases. Van't Hoff's factor is: Observed osmotic pressure Osmotic pressure calculated from law of gases. Arrhcnius' discovery consisted in the fact that the substances in which Van't Hoff's factor is greater than one are all electrolytes, and his theory offers the following explanation: Take a solution of a certain strength of some substance. K('l, for example, and calculate the osmotic pressure from Avogadro's law, and using the ordinary chemic formula for the molecule. Now suppose that out of every 100 molecules S(i are dissociated into K and Cl. or positively charged free particles of potassium, and negatively charged free particles of chlorin. The amount of substance which, in the first case supposed, would consist of 100 free particles, each being a molecule of KC1. would, in the second case, which Arrhenius' theory presents as the actual condition, consist of 14 molecule- of K( '1 and SO K and Mi ('] (SO positively charged atoms of potassium and sO negatively charged atoms of chlorin), or ISO free particles in all. Arrhenius' theorv is that these free particles behave like iMi molecules of a gas. and that hence t he osmotic pressure of such a so hit ion should be 1 .SO t lines the osmotic pressure calculated from the ordinar molecular formula. of a solution and the osmotic pressure calci molecular formula, we may calculate the percentage of which are dissociated or its decree of ionixation. The conductivity of a liquid is in a sieneral way proportionate t< its degree of ionixation. A solution of cane-sugar in water present: practicallv the same actual osmotic pressure as the osmotic pressun calculated from its molecular formula ( ' ,1 1 ,,< >,,. and. therefore, accord in i Mi:i>n vi. I.I.M TKirrrv AND KONTCEN RAYS [,, \:':..'.:.- ihe-nry. contains practically no dissociated molecules or .. ;. accordingly, lie a non-conductor of electricity. Thu .\ci i his t heory. there are many cases ill "which {i sail becomes , : li-.-ociated hv being merelv dissolved 111 water. But . ... ii -i; it ion i.- into ions or chargei I part ic Irs oi' two sii'hst ances. and - n,;i\ l>e ijuiie ilitTerenl trom those oi the separate sub- i-iiiM Ives. The separate substances, elements in some cases, tiic charged particles or ions give up their charge. . _:;:: similarity between the cliemic ]>rocesses and . i't'.'Ci in ;in electrolytic cell and in a voltaic cell, the only i-"i nri il dit'fi n nee being that the processes are reversed. The chemic nt in; t he react ion taking place while charging a storage- means : a dynamo are simply reversed when t lie storage-cell is LT'-d. At first it is acting as an electrolytic cell, and, in the second case, it acts as a Voltaic cell. !: e tin : case the current is produced bv the motion of cations in anions in the other direction : and tin currtnt is said ;., convention) to take the direction of the cations. The cations carrying a positive charge to the cathode pro- d i<'f- a " c irreiit " in exactly t lie same way as the motion of the an ions can" : L: a negative charge to the anode. ( )ne motion might just as well :.;-.' d the direction of the current as the other, except for the : ' that in i he very beginning the name p^A'^nv had been given to the : -t; tic electricity which still bears that name; and. of course, the -.vholc electric nomenclature must be harmonious. The Mechanism of Electrolysis. Several important facts have h< '. ":>- rved. The current strength is the same at every cross-section ^I'nple or undivided circuit. In the case of a voltaic cell whose .' - are connected bv an outside wire t he same number of amperes through the win- and at the surface of e it her elect rode and ' he electrolyte. The current density, however, varies according of the cross-section Jit any part of t he circuit , since the same ertricity flows at each cross-section at the same rate. true in i he case of an electrolytic cell, and even when :dc cells and electrolytic cells and simple conductors are ;i simple circuit, /. <:, in series, not in parallel or in shunt. 1 ' cteil m series with an electro- -ed into oxygen and hydrogen, ' ' '._ r cord~. I lie sa me current n 1 to be flowini: I hr< nigh t he DYNAMIC KLKCTKICITY 257 electrolyte in either voltaic cell, through anv part of the conducting cords, through the galvanometer, and through the electrolytic cell. Kven in the latter the same current strength is found in the narrow column of fluid between the electrode and the general trough of fluid, and in this larger mass of fluid. The products of electrolysis appear only at the electrodes. In the electrolytic cell in Fig. 193 bubbles of hydrogen gas appear at the surface of one electrode and of oxygen gas at the other, but no bubbles of eit her gas arc' seen in t he liquid between t he two electrodes. ( 'hemic tests would not reveal t he presence of tree oxygen or hydrogen except at the electrodes, and in the liquid and in t he air-space above the electrodes into which the bubbles of gas rise. A striking illustration of this fact is presented by the pole detector (p. 2\\\ in which the cm-rent pa.-.-es through a liquid which contains a dissolved substance which is colored red by the free element which is produced at the negative electrode. The red color is seen only at the negative electrode, not at the positive electrode, or in the liquid between the two. This means, according to our accepted theory, that the ions of this substance which are diffused all through the liquid with a general motion from the positive to the negative electrode present the ordinary physical and chemic "properties of the substance only when they give up their charge on reaching the negative electrode. A solution is used in the pole detector which does not give a discoloration with the sub- stance liberated at the other pole. Phoresis. The passage of an electric current through an elec- trolyte is accompanied by the transfer of one substance to the positive electrode and of the other substance to the negative electrode. The latter has become familiar in electrotherapeutics as cataphorcsis. An experiment of Sir Humphrey Davy demonstrates at the same time the carrying property of the electric current and the fact that the free products are usually demonstrable only at the two electrodes, and not in the intermediate fluid. Three glasses are used i !"!<:. 194'. The glass a into which dips the nega- tive electrode contains a solu- tion of sodium sulphate: h. the middle glass, contains a dilute svrup of violets, and r The glass connected with the positive elect rode, conl ains wat er. The glasses n and h are connected by a moistened fibrous cord ot as- bestos, and l> and r are connected in the same way. _ After the electric cur- rent has been applied for a certain time, all t he sodium sulphate solut ion will be found to be decomposed, and the soi into which the negative electrode dips, am be found to have been carried thfouj of syrup of violets to the glass c, into whit The syrup of violets in the middle glass although it is such a delicate reagent th; a red color or a drop of alkali a green color in The direction of the phoretic current is z. ... from the positive to the negative electrode for bases and in t opposite direction for acid radicles. 17 .",s MIDI. AI. i:l.K< TKlrlTY AND KoNTCKN HAYS i- more electrolytic cells may lie connected in scries by po- i- moi-teiied cord-. a> iii Fin'. I'.M. or the liquids may be separated .- earthenware partitions. In either case the series of - act.- ; - :i -illirle electrolytic cell of the most ])erfect type, for. as we - r!i. tin products of electrolysis are separately collected in the 1 . i-ll.-- ,'j ether these products be gaseous, solid, or liquid. The Human Body an Electrolyte. The importance of the subject sis Iii - in tlie fact that the human tissues form an electrolyte. Mfect> n] the current are most marked at the electrodes, and in a-e- include visible chemic decomposition and phoresis. I )eminerali/ed gelatin is electronegative, and a very slight addition electrolyte make- it electropositive. Demineralized gelatin has lingly -liirht conductivity, only } U ,,lj7^i. according to D'Here, 1 nd gelatin may be demineraliaed by electric dLilysis. Two or more electrolytic cells in series, but connected by metallic .: -. instead of a pop>us partition or moistened cord, act as separate lls, bach cell in such a case has its own two electrodes, lyte is decomposed into two simpler substances, without e changes occurring in the other cells. There is practically the contents of the different cells, and practically no f the contents of one cell to another. The qualifying , because even the metallic wires act to a slight extent . mid the transmission of a current is accompanied by ion.- Ml metal and other substances through the solid ffect produces no perceptible result i' 1 the case of the t an electric current for a few minutes. A case in which e a demonstrable result is the experiment of laying a zinc M copper one. and leaving them undisturbed for months t'- electric current g(-nerated by the contact of the two ;;!.- i- a feeble one, but is none the less accompanied by the n-, and at t he end of the experiment chemic analysis shows i xinc iii the coj)per di.-k and of copper in the zinc disk. The Mechanism of Conduction Through Metals. According to rtion of every metal is normally ctrons, which are all negative, and a residue ns of the metal. These ecause they are deficient in the hey are associated when in lat ively fixed in posit ion, but among the atoms of metal, and a p' >sit ive impulse is - L r at ive impulse at the other. Iriven ti >wa I'd the ppo.-hc to ci in.-t itut DYNAMIC KLK< TKKITY 250 Phenomena at the Electrodes in an Electrolytic Cell. A. At the Anode. A metal dipped into an electrolyte becomes subject to 1 he force of osmosis. The metallic ions have a strong tendency to dissolve in the liquid if an electric current is passing through the metal toward the liquid. This means that the metal which forms the anode of an electrolytic cell in many cases loses posit ivelv charged particles to the electrolyte. These are always of one kind if the anode is of a simple metal, but if it is of an alloy, such as brass, the cations passing into the liquid from the anode may be of one or other metal composing the alloy, according to circumstances. This cationic action is sometimes the sole means of effecting the passage of the current from the anode to the electrolyte. This is the case with the zinc electrode of a voltaic cell, where the amount of current is fully accounted for by the amount of zinc dissolved. This is the effect produced in mercuric and other cataphoresis or anodal diffusion. In other cases very few ions of the metal anode pass hit o the electro- lyte 1 , and The transmission of the electric current is effected almost entirely by the (lixc/ntrt/i of an ion K brought by the electrolyte to the surface of the anode. Platinum electrodes are used when it is desired not to have particles of the anode pass into the electrolyte. Platinum ions exist, but they are not readily soluble in the usual electrolytes, such as the dilute 1 acid in a water voltameter or the tissues of the human body in electrolysis or galvanoptmcture. The current cannot be carried from platinum to acidulated water by platinum cations to any practical extent. The process taking place at the anode consists almost entirely in the discharge of oxygen anions resulting in the evolution of free oxygen gas and the discharge of free electrons (negative, of course) which enter the platinum anode. Exceptional ways in which the electric current may pass into the solution from the anode are: 1. Oxidation of a positive ion in the electrolyte. '2. Reduction of a negative ion in the electrolyte. 1. When the current is turned on the change which takes place at a platinum anode immersed in a solution of a ferrous salt, under some circumstances, converts it into a ferric salt. This contains more- highly charged cations (positively charged ions which tend to travel through the electrolyte toward the cathode"), and consequently involves the transfer of positive electricity from t he elect rode to the electrolyte. This is done according to the electron i heory by the entrance oj free electrons into the platinum anode from the electrolyte. 2. On the other hand, if a platinum anode is immersed in a ferro- cyanid solution, the passage of the current produce- a change to tern- cyan id. a negat ive ion of a lower charge. 1 fere t here has been a t ran.-ter of a negative charge from the electrolyte to the anode, and this also ae oi free electrons from the elec- P>. At tin Catlindt . 1. Ther In ordinary elect n iplat ing i he fre lyte upon t he surface of t he lose their posit ive charge to t according to t he elect r< >n i negative) pass from the cath '2. The forttifltitni "t mi ntt/nn, circumstances. Thus, n platimu JliO Mi:i'!i Al. KI.Kt THICITV AND KOXTGEN HAYS Ivte kept saturated with chlorin ga- will produce a certain number of chiorion- < n aniou-. Tlir other method- by which the current sometimes passes from the >lyte tn tin cathode an- also t h" reverse of those at the anode. ;;. l>iminuti"ti of tlie positive charge on a cation by chemic . . I. hiciva-e I'f the ii'-irai ive charge mi an anion. by oxidation. Phenomena Occurring in the Electrolyte. It is not necessary -> ;i . ;,. : :- -. re of free electrons in the electrolyte. There are - . hers nf cations and anions in the solution. These ite directions, and the sum of the electric charges .-:.; h\ them constitutes the total electric cnrrent. Ions have ;_:<- Hi mobility. If. in a certain case, the cations are r< :, times the speed of the anions. then ten times as much of current t hi ough the electrolyte will be made up of a transfer : : -/. charge by the cation.- as of a negative charge carried by ':.- .: >ns. The current is then said lobe mostly cationic. Speed of Ionic Migration. The motion of the ions under the electromotive force is. on the \vhole. a drifting movement . ' it her electrode. The individual ions do not traverse the entire lually increasing velocity, as they "would do if there ' constant electromotive force to be considered. On the . ' In y tnovf a certain distance and then collide with other ions - and lose their acquired velocity. If they collide with el\ charged ions, the charges on the two are neutralized, and ce :ts ills- x-iated inns temporarily ceases. The effective mobility '- velocity of the ions, including periods of rest, at a poten- .. ' ' o] 1 \-i h per centimeter, is in an aqueous solution for ic chanties are propagated through electrolytes M' a.-un ':. nts have been made by Sir Oliver anner: A irlass lube filled with jelly consisting chlorid, and a little phenolphthalein com- Irocliloric acid. 1'latinum tin 1 current pa-seil from the hydrochloric acid it ion (it h vdi'i igen cat urns into ' ' - in ' he eli ct rolyte. The ". ( . ill be remembered. of water, ' inn. After t he flow ''' ' he sulphuric delicate test for acids DYNAMIC KLKCTIUCITY 201 the sodium chlorid jelly the hydrogen ions collide with chlorin ions which are present to form hydrochloric acid molecules at different points in the electrolyte as the hydrogen ions advance. The free hydrochloric acid thus produced decolorizes the phenolpht halein. In the other experiment the ions of the sulphuric acid radicle advance through the electrolytes in the three 1 jars without forming molecules of free sulphuric acid until the ions reach the anode 1 and lose their electric charge'. The ions which have 1 collieled with oppositely charged ions have formed free molecules of a salt ne>t of an acid e>r alkali in the intermediate portions of the- electrolyte. Hence the delicate reagent for free acid or free alkali has not been affected. The Velocity of the Ions in an Electrolyte and in Gases, and of Electrons in Metals. The figures found by the method described above' are astonishingly small compared with the velocity of the ions of a gas 20,000 miles a second in an ./'-ray tube, or, compared with the rate of transmission of elect rich v bv metals, LNs.ooo miles a second. In the case> of metals, however, the transmission is effected not bv ionic- migration, but by the migration of free electrons. Conduction by Fused Salts and by Metallic Oxids. Salts and metallic oxids at ordinary temperatures are very poor conductors of electricity. The former become good conductors if they are melted by heat, and it is very readily demonstrated that their conduction is electrolytic. In fact, this is the method adopted in obtaining some of the rarer metals. Magnesium may be obtained in this wav. An ordinary clay tobacco-pipe with an iron wire from the negative pole of the battery passing into it through the stem is filled with a mixture of chlorid of potassium and e-hlorid of magnesium. The salts are fused by the heat of a Bunsen burner, and a graphite anode from the battery is dipped into the 1 melted mass. The conduction is excellent, and is accompanied by the liberation of chlorin gas at the anode, and of me-lte'd metallic magnesium at the iron cathode in the bowl of the pipe. The comparatively infusible metallic oxids. such as the oxid of zirconium, are made use of in the Xernst lamp. There is a "heater coil" of platinum wire through which the electric current is first pa>sed. and in which sufficient heat is produced by ohmic resistance to bring t he "glower," consisting of metallic oxids. to a temperature at which it becomes a conductor of electricity. The current is such a powerful one as to heat the "glower" to bri advanced for believing t hat case of oxids of t he met als incandescence is electrolvtic ; ret ically. if t he conduct ion w in met als. the suhst ance sin ml are t transparent . A st ronger re; of a mixture of the oxids of tw t hues found to be im >re concent I 1 ; The Passage of Electricity manliest 1 v due to a migrat ii <\\ ductor, but the fact that such a even with very weak current.-, war piece of gold and a piece i .1 n >ppi The 1 weak current pn idliced by t In during this long time caused a sufficient migration of ions in e; lion thoroughly to saturate the gold with copper and the copper with gold. The ioni/ation of a metal thr >ugli v,i,;r;i electricin ;- couducti d _',,_' \1!.1>1( \1. U.l.i' I'KiriTY AND KOXTCiEN HAYS h:is important therapeutic list's and so docs the effect upon the tissues . :i ni;:i:il body. These are essentially li()Ui\l, and an important : .-lee: rot herapeutics is concerned with the changes pro- is.-a.m- if an electric current. This will be con- ; ir :v is ; iw; \> ::."iv or less resistance to the passage ot a current and this depends partly on the nature of the sub- . , its diameter and length. Substances which , .-. ic; , v . ' : '/'. verv well are called conductors; t he metals are con- ,;; ,;-. >o: han others. Substances which conduct electricity ... : iv used to prevent its escape from conductors are inductors or insulators glass, rubber, and gutta-percha THE THERMAL EFFECT OF THE ELECTRIC CURRENT T' nl of electricity passing through a good conductor, stich as a - the coiiduct(r to a certain extent. This effect is . :_''.- ::. case of a cupper wire to the production of heat by i:i motion, and in the case of a short straight wire . any other wire or magnet or magnetizable body, lost bv the current in passing through the wire ,'hii-h is converted into heat. The conditions expressed in nee show that no work is being done by the current simple overcoming ot' nhniic or frictional resistance in the -, 'ii of power through the wire. In a case of this kind the o] .; produced depends upon two ijiiantit ies: the resistance asured in ohms and the strength of the current The amount of heat is expressed in grani- - iltiring to raise the temperature of 1 gram of water . la t ions give the amount of heat generated in one ; cm (' ampere.-,, with K volts, through a resistance the wire wijl be raised will be greatest, '.;:.' of heat is concentrated in a short length of i he ci >nd it ion > prevent t he rapid radiation of '"!'. In n-ifai'd lo ilie last point, an inclosed ~ ii"' 1 ''!' than the same i(lentii-al motor without i ii' ' : -' fad is found in t he incandescent lamp. ' ' I>P -i '.' a resistance ol '_'.")() ohms, and become a current of ', ampere; while the same \ :>'" '.' win .' ., inch in diameter and unti-1 t he i , i -tatice and irenei'at e t he ' in a -ecutid, 1 ) : i' wit hoiil ;i |iercep1 ible I ' I.-H-T , thi case oi | ' i| inch ci ip])ci' wire, ' ' even as much as -'ill n< it pr< iduce a maximum elevat ion DYNAMIC KLKCTKICITY 26:3 ((' = .), ;ind in therapeutic applications the resistance is greatest with a small area of contact between the electrode and the body. A sponge electrode with a surface of \ square inches may, for example, be applied to the nape of the neck, and the other electrode consist of a silver probe making a contact with the mucous membrane of the gum over an area of perhaps only .',, square inch. The same current is passing at both places, and the amount of heat produced at each elec- trode is proportional to the resistance at that place of contact. There would be no perceptible warmth at the sponge electrode with a current of 1 or 2 milliamperes, while at the electrode applied to the gums, where there is a great many times more resistance, the heat would be very disagreeable. The factor of heat at the contact surfaces between the body and the electrodes probably has something to do with the reduction in resistance which occurs after a short period of flow of the continuous current. This lessened resistance takes place when the electrodes are applied to a wet thread or to a nerve which is apparently homogeneous. It can be demonstrated by the VVheatstone bridge. The production of a large amount of heat by electricity involves two factors: the flow of a heavy current through great resistance. A marked rise in temperature is obtained when a large amount of heat is generated in a small portion of matter. The human body is not (^specially favorable as an object in which to develop a high temperature by electric currents. The resistance 1 of the body is so great that the strength of the current transmitted is very small indeed in comparison with metallic conductors. And the small amount of heat which is generated is quickly removed from the point of contact, partly by the circulation of the blood and lymph and partly by ordinary conduction. High-frequency currents are an effective and often very beneficial means of producing a large amount of heat by their passage through the human body. The fact that a boy's arm and leg may have to be amputated in consequence of circulatory disturbances from contact with a wire carry- ing 6600 volts and without any burn is very striking. The heat generated by ohmic resistance to the passage of an electric current is utili/ed in electrotherapeutics especially in the following ways: first, in making warm or hot compresses; second, for cautery: third, for the diagnostic and therapeutic application of light and radiant heat. It is also the ba>is of the hoi wire milliamperemeter (see page 174). The galuanocautcry applied for surgical operation is an entirely different matter. The heat is not produced by the passage of an electric current through the patient'- body, but through a metal wire or strip which lias a resistance which though considerable allows ihe passage of a very heavy current. The resistance is a great deal les> and the current a great deal stronger than i- ever the case with the human body. The large amount of heat which is generated is produced in a very small mass of metal, which is accordingly raised white heat. It is the hot metal which cauterizes the fl elect ric current . Reaud's Electric Thermostat. Thi- is an example of th lUi'Al. l.l.Kl TKirlTY AND KONTGKX KAYS [i consists of an hermetically sealed glass tube of a U shape, partly tilled with mercury. The upper part of llic left limb contains rarefied hydrogen i:a>. whi'rii l.y its pressure maintains the mercury at a certain level, leavini: a vacuum at the top of the other limb. A leading-in uuv fi-i.in ' tic elect ric-lidit wire reaches the level of the nuTcury in it, - tube, and Hi*' current is transmitted through the mercury to the leadinir-in win-, through the heater //, and thus to the other Tlic whole apparatus is placed inside the bacterial hamber, or whatever space is to be heated to a uniform tem- . It' the temperature rises beyond a certain point, the hydrogen and depresses the level of the mercury in that arm of the uch an extent as to break the contact with the leading-in wire of;' the electric current. The thermostat may be adjusted for any desired temperature by adding mercury stored in a little side tube NI that in the mam tube, or by pouring some out of the 1 main tube into ibe. A -nil finer adjustment is made by inclining the tube n ]>er cent . A cell of thi- t\'pe becomes decidedly Peltier's Gro- elect ric current upon t he wire of elect ric irreat pract ical importance ('see page 222). ' - ; /.'.."""/ "/ i'Ju-lricilii.- \\'hen a bar bar oi bi-mut h and 1 he negat ive pole is ace ( >j union i- cooled and it is even 1 -. I lever-ing t he current produces d ion. DYNAMIC KLKCTKK'ITY 205 The Temperature Changes Produced by the Passage of a Current Through Different Electrolytes Outside of the Battery Itself. - These vary just as much as do those in the fluids of a battery in opera- tion. There is always a certain amount of heat due to the ohmic resist- ance of the liquid. '1 his may be augmented or diminished by the thermal effect of the chemic change induced in the fluid by the passage of t he current . Placing a 1 )aniell cell in t he circuit of a powerful bat t ery which sends a current through the cell in a direction opposite to that of the current which it tends to generate, we should reverse the chemic processes which normally take place in a Daniell cell. The thermal effect is also reversed, and the cell becomes hotter instead of cooler. The ordinary process of charging an accumulator or storage-cell by sending a dynamo current through it in a reverse direction also reverses the thermal effect upon the cell. With the usual strength of acid a storage-cell cools slightly on discharge, and is warmed slightly when being charged by a current sent through it in the reverse direction. Generally speaking, the thermal effect of the chemic change from passing a current through a liquid is to produce heat if the chemic reaction is such as would ordinarily do so. and to produce a cooling effect if the chemic reaction indicates that heat is rendered latent. The Heat of lonization.-- An electrochemie equivalent of any substance causes either the absorption or the liberation of a certain number of joules or heat units when it becomes positively or negatively ionized. In the cases in which heat is absorbed at the pole where a cer- tain ion is produced, this usually means that work must be done in order to cause the substance to enter the ionic state. When this is the case, it will usually be found that heat is liberated when the substance leaves the ionic state. Topper is such a substance, and its heat ot iom/aiion is +',]~,'200. Zinc behaves in the opposite way: it takes work to brim: it out of the ionic state, heat being rendered latent and the temperature falling at the polo whore this is taking place. I nder the conditions present at the pole where zinc ions are produced the temperature rises because heat is liberated. In entering the ionic state zinc actually performs work in heating up the surrounding medium. Its heat ot ionization is ( ,),5(JU. This means that one electrochemie equivalent of zinc in entering the ionic state loses lid. 501) joules of energy in the form of heat. The heating of liquids (electrolytes or not) by ohmic resistance is one of the disadvantage's of the liquid interrupters and rheostats used in electrotherapy. Kxamples from outside the domain of electricity illustrate the subject of latent heat. Salt and ice mixed together have a strung tendency to form a solution of salt in water, and this is accompanied by the absorption of a large amount of latent heat. Such a mixture forms a freezing mixture. Water and sulphuric acid have an equally strong tendency to mix and form a solution of sulphuric acid, but in this case thi' process is accompanied by the liber Anvthing like a complete discussio would carrv us too far into the dotnaii It may be added, however, that the t"i' be those which produce electromotive lore The Degree of lonization May be Determined by Cryoscopy.- Raoult's discovery that the free/ing-point of a solution depends upon the number of molecules held in solut ion was immediately followed by _V,t, Ml Kit AI. KI.KCTHICITV AM) ROXTOEN RAYS li-covery tiiat -olution- of -alt- and sonic other compounds gave PI - .'- corresponding i.i ;i greater number oi molecules than would he ir ciiemic formula-. 1 his has hccn explained hy :;'r;s "ii ' : - thei-rv of dissociation of ions. He supposes that in .imr-p"i:it depends upon the nuniher of dissolved Pericles (either i-niire molecules or dissociated ions formed hy the ii i.] . ;;!.-'. \\ i- inav then say that one gram-particle 1 i i: .- '. i if : -:: i ,-i: "leciile dissolved in one liter lowers the frcozing- |.s.~i ! i 'i i ( '. The numlier of decrees that the freezing-point is . i. divid I b\ l.s.") 1 1 )(>'('., will give the number (X) ol gram- - icl, - d!->olved in a liter of the liquid: 'i he r : iii In r thus f"unil \vill he the numher of gram-particles, both 1'-.- and dissociated inns formed by split-up molecules. Tii" ' ;>er "f ^! - am-molccuIes. X 1 in the substance is known i'ro'm its i:. . and the amount or weight of the substance which ".-: .:. making the solution. The number of gram-ions is in iber ol gram-particles (X) minus the number of ;ram- .,- \" . :.- number oi gram-ions is made up of negative and positive ions: one ot each polarity for each molecule which is broken up, me molecules split up into a greater number of ions. A Iphate of copper M'uSOj splits up into two ions a : |er i'n f('u) and a negative sul])hion (.SO,). he number oi molecules placed in the liquid and '/ is the liss' iciat ion, t hen - i. N ' tin ilecnlcs are dissociated. N : '/ -\ ! Jin ileciiles are intact . . ''"i molecule yields _' ions, there will be ''2 "- X 1 ions. in solution X 1 - '/ X 1 molecules and 2 X 1 ions, and il ' i the number of particles found by cryoscopy from : Uftoti t he freezing-point . - : '' 'ill : i:ives '/. the coefficient of dissociation: the c i of hy. In m liy it - vnlcncc nr i lie nuinlicr ifc i if i >r coinliinr \\-it I:. l iMnncc, ('it her siin]ilc or com- 1 i|ili\ ;tleii1 of the Milt:mre to il -olut ion of |i(it;i--iutn dilorid nn:il -ol ' ' if ii -iiliMam-e. and i- a quun ' ' \pre-.-ed ill LM'alll-. ',]' < T di ociateil comlit ion \ : . i~. 'ion i- e, |iial to the .-11 II I of DYNAMIC KLKCTUICITY 207 The following is a concrete example. A decinormal solution of CuSO,, or one in which 0. 10 gram-molecule (!.">.!) grams bv weight) of CuSOj is dissolved in 1 liter of water is found to have had its free/ing- point lowered 0.2.'$ C. by the addition of this amount of CuSO,. The numl)er of gram-particles calculated from the fact that 1 gram partu-li- in a liter lowers the free/ing-point l.s.VC. is found to be 0.12132. Hence (I !>.!! M ]() 0.213. A calculation based upon the freezing-point shows that, in a decinormal solution of CuSO.,, 24 per cent, of the molecules become dissociated into ions in the mere process of entering into solution. This agrees very closely with the calculation based upon the conductibility of the solution. Osmotic pressure, freezing-points, and electric conductivity are all determined by the degree of ioni/ation. Observations by .Maillard. 1 Loeb.- Paul and Krfmig :! lead to the belief that the ions in any solution are the active agents in any effect upon living tissues. The effect of antiseptics is due. according to Paul and Kronig. practically entirely to the ions. The degree of umi/.a- tion of a metal, as in a solution of bichlorid of mercury, may be reduced by adding to the solution ions of some other metal with the same anum (XaCl per ex.), and if the latter are non-toxic, the toxicity of the solution will be reduced. An experiment was made with anthrax culture smears dipped in a solution containing 1 gram-molecule of bichlorid of mercury (this being 270 grams in weight) in Hi liters of water, and the number of spores which survived after an immersion of six minutes was found to be only eight. Hut if 1 gram-molecule of sodium chlorid, XaCl (weighing ~>s grams), was added. 32 spores sur- vived, and the culture showed 32 colonies, \\ith two gram-molecules of sodium chlorid the number of colonies was 124: with 3. it was 2S4 : and with 10, it was 10S7. The strength of the mercurial solution was the same in each case. The. absorption of moisture and the interchange of substances in solution through organic tissues which lorin the basis ot animal and vegetable life are all dependent upon the number and properties of ions. The theory that all life is but a manifestation of electricity is. therefore, not at all an impossible one. The further theory that all matter is of but one substance, either electricity or variously modified by electricity, is one of the picturesque possibilities of the future. 'Journal . ELECTRICITY OCCURRING IN ANIMALS AND PLANTS . . , _ p,it 'Mini between portions "1 the surlacc oi \-:iich an 1 so vvnerally present arc seldom as great lie torpedo. They generally require special . .; detection, but it is none the les.- probable thai they i; pnrtance. Kledricity is ( levelo] >ei 1 especially ill the till ssues. notably the nerves and muscles. 1 he : , . among many other structures, manifest it. /'/' , . ;; Brazilian plant said t<> have been lately , [(rlain electric properties, and the charge b\ contacl with ii i.- claimed to be equal to that oi \),.'. ie] Mr.-nenil law noveming the difference in potential between - , : ;.,. , ;/"/, i> i ha .1 it develops only when there ;;r'f, ;-,.; (. , ';.. [' ;\ tile HalUl'e or 111 1 lie acllVll V of the cheillic ] )1'O- , in the t\vn ivL r i"';-. \\'hen there is a difference in . _' ,;i ' here [H'ocesses of decomposition arc in excess is nejia- . .: :, '_:'_ in \vhere synthetic processes are in excess. It both are - . |i isition, the one at \vhich l he process is most active i tiii iiher. And :: both are regions of synthesis, the least . > -'' '.-. to tin- other. ! :.. ; '. ;' un ; " twecii the electric potential at the two ends JL'. :.'':.: fi-l't ili/ed or imt. Ida Hyde 1 ha- tested this l>y i-apillnrv electrometer, i he (lit'fcrence in potential in the - _'_' .'.'. ;i- ' 'j' ; - d'-\'elopmelit progresses. In Some other eggs : 1 .: ; . , ' stages of scginent at ion cause rhythmic iwer.-al- of the direction of the cui'i'ent. The sources i- an anabolic ; ine changes in t he chromatic: . changes in t his mass in act ivity. v;-c( ;; \- and -'i rl ace ten>ion. ent par' S of t lie li\'!!;L r b' idv. I ; l'i Ull i! o' he] '. .' ; ;ict ivit ' elect 1'olnol i\'e fi il'CC 1 i> a ' ef\ ! ' M >V < induct i if, ( ipposite ' d if the sill-face. Ifed- KLKCTKICITY ( )( ( f HRI N( i IN ANIMALS AND PLANTS 269 that the current of demarcation was verv much increased. The infer- ence was that activity of the spinal ganglionic cells is accompanied bv electric phenomena of the nerve-trunk. Electric Currents in the Skin. Skin may be removed from the body and still retain vital proper! ies, as shown bv its survival and growth when used in skin-grafting. As long as the skin is fresh and possesses vitality, it may be shown by appropriate electrodes and meters to possess electric properties. A current will generally pass from an electrode applied to the inner surface of a piece of skin through a con- ducting wire and meter to an electrode applied to the outer surface. This may be called the current of rest, and in the case of a piece of skin freshly removed from the bodv, the internal surface is usuallv positive. it is necessary to have non-polari/able electrodes, and to be sure that the results actually indicate a difference in potential between tin- two surfaces of the skin. Without anv special precautions it would be easy to have an electric current produced bv a difference in the degree or kind of action upon the two electrodes bv a difference in them or by the difference in the chemic composition of the moisture upon the external and internal surfaces of the skin. In other words, the skin and the two electrodes might form a miniature voltaic cell unless precautions were taken to prevent such an effect. Current* Produced b;/ Contact of tin I nn< r and ()/dir Surfaci* of th< Skin with Saline Solution*.- These may be detected by the same method as that used by Chano/, in the case of acid solutions. A piece of skin is fastened over the end of a tube filled wit h the solution, and dipped into another filled with a precisely similar solution. An electric current will often flow through suitable electrodes and conducting wires passing from the liquid in one tube to that in the other. '1 hese currents were one of the early discoveries in elect rophysiology and have been experimented upon by DuBois-lleymond. IMS; Rosenthal. l^b'-l: Roeber; Kndemann: Hermann: Bach; Oehler: Bayliss: Bradford: Reid; Tallport; Waller, 1 <)<)!. Current* Produced h*/ Contact r and ()ntt the Skin with Acid Solution*. Chaimz'* Ob*< rmtitnis. An experiment by Chanoz 1 illustrates the method of detecting bioelectric currents and or dead skin lei er, is i >pen at one en. band. Both ends of the tube dip into vessels of the solution t< tested and the tube is also completely tilled with the same solution. Kach of the outer vessels is connected by in ipolarix.able electrodes, zinc in a solution of sulphate of zinc, with Lipniann's capillary electrometer. l i ven ess and -mail electric capacity, i by two \Yeston cells, i- used for determining the difference in voltage without any calculation. The piece of skin is taken from a frog which has ju-t been killed, and the experiment performed so quickl/ that the current is teste,] in one and one-half minutes after the incision has been made. The experiment is made to determine the difference in potential between the outer and inner surfaces ol skin, when both are exposed to a solution of the same material and tin strength. .-, .Juh 17 ami _' t. I'.MI:>. i':.,- ports the following results: (1) At the moment of . die elect mile connected with the capillary elec- [, ; the internal surface of the fresh frog-skin is always positive ,-,. ; ind the direction of the current is as shown in ;,,. _' |'he :.:-::' : "'i of the positive condition varies with dif- ; 1 ,-oluti 'i,s. It i.- soon reduced to zero, changes to a neg- , becomes /.en i. When the fluid is a cen- oi Ilxi,. the inner ,-urface of t he shin immediately [, -it i\-e. and the change to a negative com lit ion occur.- wit h in ten minutes, if at all. \N it h a cent i- :, tir normal solution of HX< >., the change 1 i , trom a ])ositi\'e to a negative conui- t ion occurs in alu >ut a minute, and t he negative condition lasts for several 4- minutes. 10 A piece of skin no longer presenting a difference in i potent ial after a cert am duration of contact with rather a strong solu- difference of potential, sm-h as would have Keen obtaim-d at iir>t \vith a - i! i'inji. 1' The frog's skin ciintiiiiH-s to ^i\-e electric reac- i - 'id soj itiiiiis as l-i!L r as two or three days after the fro-: :. - ii.-i-i 1 1 '."7. ex]ilait:s thoe facts by the theory that strong ac;ii~ : tnoj-e po^.s-crful stimulants to tin- .-km than weak ones, and lirecti .ii of the ciii'i-ent of rest more quickly. i 'Inn _ , , ese facts and of the results reported by I.I)' hoi IT for a lon\ [n-esent : LI a M'^M ive varial ion, o| . t t.c-e cii :"' !,' ' hen,, in, i : ' ' ' : ' en.brane dit'f cable Tlie Current of Hc-t. \\ ELECTRICITY orcURHING IN ANIMALS AND PLANTS 271 plate in a voltaic cell, and if a wire is connected with the two portions of the body, an electric current will flow through the wire toward the portion which is " negative to t he other." The portion which is negative to the other is a region of lower potential. It is not necessarily charged with negative electricity. In the tissues themselves the current is continued from the region of decomposition to the region of synthetic activity. D'Arsonval's explana- tion is that the difference in potent ial is dependent upon react ion between oxidizable substances in the tissues and the oxygen in the blood plasma. Currents of rest are electric currents the result of the above-described chemic processes, and are continuous and uniform for long periods of time. They present in this respect a striking contrast to the currents of action which develop suddenly in consequence of some irritation, and as rapidly cease to flow. Currents of rest in mucous membranes flow from the excretory surface of the glandular epithelia to the sur- face where the epithelial cells are in relation with the blood-vessels. If it were practicable to connect an external circuit with these two layers, the current woidd flow through the wire from the vascular to the secretory surface. The latter corresponds exactly to the zinc pole of a volt aic cell. The current between the layers of a mucous membrane is transmitted mostly by the epithelial cells, and may be called an entrant glandular current. In the skin the current of rest is generally from the internal vascular to the external exfoliating layer. It is, therefore, an emergent current. There is no current of rest in uninjured nervous or muscular tissue; but whenever such tissue is injured, the damaged portion becomes negative to any unin- jured portion. This produces a current of rest which may con- tinue uniform for several hours. it will continue as a current between dyim tissue^) and uninjured ones. The current of rest has long been the case of muscles and nerves in the way shown in Fig. 197. A nerve or a cylindric portion of a muscle in its natural position is divided by two transverse incisions and an external circuit is applied with a delicate measuring instrument. Currents will flow throuirh an external circuit from any point distant from the center of one ot the transversely cut surfaces to any point nearer that center. The diagram shows a number of such external circuits with the direction of the current of rest through them. It will be seen that the surface across tin" muscular or nervous libers is the muscular or nervous bundle. It is fo properly and in bv reference 1 to points may be determined. The point in either direction, is negative to a pi is true whether the points are on the equator. Applying the test elect rod transversely cut surface, at the end: the which the polariu \\ hich is furt her froi lint nearer the equal > >r same i >r on opp< isite sii s to the middle poin accordingly be found that there is no difference in potential and hence :. < irn t. !':. insertion of a tendon into the periosteum of a bone corresponds to a Ira! >\vrselv cut surface, and accordingly a current ot rest is found to exi.-i if impolari/.able electrodes are applied near this attachment ;md t" t in -mi'iace oi t he muscle or tendon. Kxperiments have been made by Bernstein and Tschermak upon ,; ivst in muscli's i" determine whether there is a pre- rxisteiit dilTerence in potential between the transversely cut surface of a i its longitudinal surface, or whether the difference later in consequence of chemic or other alteration. Bernstein - thai t'he current of rest shows its maximum strength innne- dia'ely. S. (Jarlen 1 thinks he has shown that llMll y or -, -,?,->,-,- second rlap-e befoiv the current develo])s. And when the muscle is cooled, M! of . : ' - second may elapse. A carefully prepared muscle upon whose longitudinal surface are placed two non-polari/able electrodes wet with Ringer's solution does not \i\ : rest (Biedermann). But R. Hober finds that a if rest develops when the extremity of the muscle is dipped into a solution of potassium chlorid. Other solutions which produce is I'ft-ct : re oi salts of lit hium, sodium, cesium, ammonium, rubidium. nth the an ions C, X. S. \( ).,. I, P>r, Cl, acetic acid radicle. S< >., tartaric ainl citric acid radicles. In each list the last is most favor- able ' < velopment of a current in the normal direction; that is. c .": : to a negative condition of the extremity of the muscle. I.. Hermann's experiment was performed by means of a fall-rlieotome .1 - : - ct 1011 ' i i rough t he muscle simultaneously wit h its mak- ::._ r 'he contact of an electric signal. The tune that may elapse before >p!!i'-ni of . -i current of rest may be the time it takes the injured ::.;-,:,:: -ub-taiice to die; or. according to DuBois-Reymond, it is the the sriiiipi nneable membrane takes to lose its permeability negative ions o| the muscular fiber. 1 . 1 > . ' -'.:; and \. I -ci.cri :ia k" have pt rtormed t he same experiment .' !' r : :'< exact c >ndi' ii ins with an electric motor and photographic '. ' ' -hown the presence nf a current of rest in an econd. '1 his re-ult is more in accord with the ' ' ce oj t his muscular cur n -nl i han with any 1 heofy 1 could occur in such an iufinitesiinally nerves has been studied liy K. Hellwig. 1 He teli'-e ;> pro\-ed b\" the corres[ loiidence between in-rvi . - filament , I : is an asccin 1 mi: current :'oL r . and a descending current in i he elect ric i" !!' '' '' '!. This has ;il] been established by I ' -1 ' : ' 'i M. nd<-lssolm. Schultx has studied the relation ' ' liol icin H : ;',]->< : he influence of the leliirt h '''-" "' ' ; n.xia] current . and t he negal ive : - ' : it. l'he h port fact is that 'a! and flows from the s:antrlion-cell from ' \: ' , i, "Ml 1 r . ' - ELECTRICITY OCcrUKl.NC IX ANIMALS AM) PLANTS J<.} which a nerve-fiber derives its trophic influence. \Ye should, therefore, find that the axial current in a sensorv nerve flows from the ganglion on 1 he posterior root of the spinal nerve toward the periphery in the nerve itself, while in the posterior root the axial current flows toward the spinal column. The Galvanic Muscular Wave or Porret-Phenomenon. A mu-cle undergoes changes in contract ibility when dipped into various liquids, such as distilled water, solutions of the alkaline salts, veratrin. This increase in contract ibility traverses the muscle in a wave-like manner. It implies an increase in electric excitability, as well-as in capacity for contraction. Kuhne, in ls(i(), Hermann, in is'Js, and {'.. Meirowsky 1 have studied this experimentally. 77/f Alkaline Dcniurcntion Cnrr< nt n/nl tin \\ subject. He placed the gast rocnemius muscle of a frog in contact with solutions of different strengths of chlorid. nit rate or monophosphate of potassium. This was continued until the electric potential of the immersed part remained stationary. The difference in potential between this part and a transverse section of the muscle was measured. There is equality between the two when a l.-'i per cent, solution of chlorid of potassium is used; the electromotive force generated at the line of demarcation between the alkaline solution and the electromotive force called the current of rest are equal. The addition of any colloid substance, such as albumin, for instance, reduced the electromotive force due To contact with the alkaline solution. The colloid substance interferes with the migration of ions from the liquid into the muscle. The unequal migration of positive and negative ions through a semi- permeable membrane is supposed to be the cause of most physiologic electric currents, and ions which do not diffuse through animal mem- branes should greatly modify physiologic currents. Currents of Action. Klectric currents are produced during the activity of nerve or muscle or of glandular tissue. Those in the latter develop and disappear less rapidly and may be given t he special designa- tion of secretion currents. The epithelium performing the glandular function becomes "negative" to the vascular part ot the gland. '1 he part of the muscle or nerve which is in activity is "negative" to other portions of the nerve or muscle. The wave ot contraction in muscular tissue or of stimulation in nervous tissue carries with it a state of lo\v electric potential. The current of action is considered by -some authors as identical with nervous activity, and by others as an epiphenomenon not neces- sarily accompanying this activity. I'. Schult/. :i has considered this subject of the occurrence of an electric current corresponding to the current of action, but without the presence of physiologic activity. The current of action may be passed through a transtormer or induction coil, and undergo an increase in voltage so as to produce the physiologic effect of high-tension currents upon other animals. Currents derived from heart or muscle contraction have been transformed in this way by Max Cremer. 4 He has obtained very effect ive results with 1 Archiv. f. die t^csum. Physiologic, vol. Ixxiii, p. -H'J, 1V'.. 2 Ibid., vol. civ. p. ::_'(). I'.iiH. 3 (Vntrall)latt f. Physiologic, vol. xviii. p. I>1!>, IVrcmbcr Ml . I'.'Ol. 4 Zeitsch. f. experiment. Pathol. u. Tln-i-apic. vol. xlvii. p. i:>7. l'.H).V IS 274 MI.DICAI. I.I.KI TKieiTY AND KONT<;KN RAYS a frog's heart. Ma rev. in 1S77. used a transformer in studying the electric r-hock from the torpedo <\r electric eel. The Voltage and Amperage of Bioelectric Currents. -The differ- ence in potential bet\\eeii all active and a passive portion ol the human boil\ j> fnuiul by mea.-iirement with the potentiometer to be from '."_' :<> n. us voh This i> a very appreciable voltage, but, owing to lie ven irreat resistance of the bodily tissues, the current which it mperage. (Minis' law is o])erative here, and ;he iv.MMance is hundreds or t housands of ohms, the current strength n - to between I , ainj>ere or ^ and ^ niilliani])ere ii litn rent i'a-es. In iiiea.-urini: currents of siicli small magnitude the greatest pre- . 'ii> . i-i in taken not to \-niate the results by the production of : . :'"!'>' in a pj living t he measuring apparatus. Two ordinary ; iieil to i he e\])osed muscle or nerve, themselves: : ' 1 1 ' r '1 ' ' -, ion n a complete v< >lt aic ci mple whose electromotive : _"/ !> i-veii sirealer than the physi;!;L r effect al'e t hose suggest ed by Heynault '- l'.' s . I'oth electrodes are jusl' alike, and \vhich i lie conduct inola!'ixable elect roije is not completely SO, bill IS he les- di licate experiments. It. ; ' ' ' fi?M op, i, point and filled h 1 :::.. i : IIIIMI. ii . ei-sed a of silver. eiecli-odr- , I M ; , .,. ;riied o}j aiiiouiit ing to ce TII 1 1,1 current. ' e- in tin i ijver. ELECTRICITY OCCl'RRINC IX ANIMALS AND PLANTS 275 A similar typo of impolarizable electrode consists of a jar containing a saturated solution of sulphate of zinc into which a zinc wire leads, and from which a piece of filter-paper saturated with a ,,/,, solution of chlorid of sodium leads to the tissue to be tested. The electrode from the other terminal of the galvanometer is of exactly similar con- struction. This type of non-polarizable electrode is not available when it is desired to apply the elect rometric measurement to a verv small surface. Electrodes of mercury and- a solution of chlorid of potassium are only feebly polarizable, and so are electrodes of cadmium in a deci- normal solution of chlorid of sodium. Electrodes made of gold and cadmium coupled together, or of gold and silver, or of gold and copper, or of aluminum, or of aluminum and cadmium, are feebly polarizable. The oxidizable electrodes of silver, nickel, copper, tin, or mercury are not free from polarization. \Y. Cowl 1 has made a thorough study of this subject, with the result in favor of PuBois-Reymond's electrodes of amalgamated zinc in a neutral saturated solution of sulphate of zinc. Muscles and nerves are themselves polarized to a slight extent, oven by very weak currents, without regard to the nature of the electrode. Currents as weak as 0.0044 milliampere will produce this effect. The most dedicate galvanometers are required for the measurement of these currents. The Thomson astatic needle or the d'Arsonval movable coil galvanometer, if made with a great many turns of fine wire, is suitable for measuring the current. The capillary electrometer is the best instrument for use in the potentiometer in measuring the voltage. The mercury and calomel normal electrode can be used in the way explained on p. 177 as an absolute measure of the potential of a single electrode applied to any part of the bodily tissues. The difference in potential between any two portions can be readily calculated from their absolute potentials. The current of action is always present when a muscle contracts or a nerve transmits an impulse. This occurs whether the function is per- formed in consequence of natural or artificial causes. And there is no current of action without the performance of function; and no perform- ance of function without a corresponding current ;>f action. 1 he current of action is found in the muscle when the latter contracts in pinching or pricking its motor nerve 1 . Wave of Negative Variation. The current of action or, to be more exact, the wave of low potential travels faster in the higher animal or or^an than in those of lower development. It> duration is short if its propagation is rapid. The rate of the latter is sometimes !!() meters a second. A galvanometer may be connected by DuBois-Roymond elect rodes wit h two port ions of t he length of a nerve which is uninjured, and conseqiientlv presents no current of rest. Then it an irritation is applied to some other part of the lenu'th of the nerve, the galvanometer will probably fail to show any current. This is due to the fact that when the wave of low potential reaches tl e point nearest the place of irritation, the point reached becomes negative to the other more distant point. At a later period the wave of |o- potential reaches the more distant point, and conditions are reversed. A current will accordingly pas> through the galvanometer at first in one direction and then m the other, and the alternation is aecomplisl i : in such a short space of time i Archiv. t'. I'hvsioluirif. 1 v.i. :;-.v>. Ml. I'll \1 1.1. 1. 1 IKI< 1 I "l AM) U< 'N 1 lil-.N K\YS that tin 1 ordinar\ galvanometer will indicate neit her current . A photo- ic chart of the capillary electrometer will .-how these two currents. succeeding each other and in opposite directions, and so will Hint ho veil s iraivaiionieter. which react.- with extreme rapidity. During a tetaiii ctimi ol a muscle caused by a rapid succession ol stimuli, such as the faradic current (applied at a point not included bet ween the i v, o electrodes from the galvanometer), the circuit formed by the galvan- - ' nd the incl idi-d portion of muscle will be the seat of a mono- phase al i ern at ing current . I nder these nsi rable. There is a chronologic correspondence between the myographic curve indicating; shortening or lateral swelling of a muscle stimulated :Md t he elect ro metric cur\'e indicating the wave oi negat ive . V 'i t his is true of hot h iso tonic and isomet ric contraction. Ihe most satislactory observations upon the rate of transmission of :.. "negative" wave or wave of lo\\ potential have been made upon living muscle and nerve preparations with parallel transverse sections. Ihese tis.-ues have a current of rest which is fairly uniform and is caused h\ ihe low potential at the transversely cut ends of the muscular Under or of the nerve. A potentiometer with one DuBois-Reymond electrode applied at a point on the longitudinal surface of the muscle and another at the transversely cut surface will show a constant differ- ence in potent ial, which, however, is much reduced when t he wave; ol low potential reaches the longitudinal point. The poten- 3 t ial at the latter point will not * fall below that of the trans- versely cut end. but it is reduced t" an extent and in a way which can be accurately determined. Appl;- inipolari/.able electrodes at X near cut surface and L on '' ' ; 'he nerve shown in F in. 200. Then a current flows i-.'i ' ' Ivaiiometer trom I. to X which is negative. ';'ii: current at " >>. All part* of the n7^ MKDH'AL KI.Ki'TKK II V AM) KO.Vn.KN HAYS p,,iiit. The i.nly change occurring in the absolute potential of the nearer point is at tin- time that it shows a wave-like fall, followed by a ;;,. ,, the /.i IM level. From this time on the absolute potential at the lirst point i- unchanged. but it shows a wave of nlutirrl ;/ high potential, indicat i\ e if he arrival of the area of low potential at the further point. y;, /;,, c Variation* in tin H u man Heart. These may be registered b\- a capillarv electrometer connected with non-polari/able electrodes phu-ed .';,.,;; the surface of the body near the ba>e and near the apex of the heart. 1, ,//,,, /,'.//; //,/// * -,/ \ii/iitirt' Variation in n Xcrn. Impolarizable ,, - ;l re applied I" the lateral surface and the cut end of a nerve. The hitter, bi-inii iii jured tissue, is negative to the former, and a current : ! ,..vs ''..'. ;^''. i the iralvanoineler from the lateral surface To the cut end. \ , ; [j,. ,. irrent may now be applied to the nerve by two electrodes, xe together at points at some distance, and t>oth in the same direction, from the part to be tested. This stimulation causes each ivi part of the nerve to behave as if injured. The galvanometer sho\\s a weaker current from the lateral surface to the cut extremity , ( f ;., nerve, and this indicates that the lateral surface has changed ttiv, -.: : a rieiral ive electric potent ial. h is very easv to olserve the negative variation causeil by a con- ::.;.;- current flowing for a considerable length of time, and it is also possible b\ lelicaie apparatus to show the negative variation due to a current lasting in> longer than an electric spark. Such observations as the latter >ho\v that the negative variation occurs a certain length o! time ifti-r the application of the stimulus, and that the retardation > ii proportion to the length of nerve to be traversed. The negative \ . ,. - ion or cotidition of negative electric charge advances in a wave- ihe point of ap])licatiin. The rate of propagation o! iie v. a vi' oi neirat ive vai'iat ion is found to be the same as that of the \'nr< nf I. mi- I', iti , it iii! In Si/j>< rjt'is/t inn (Hermann), when only the absolute potential at a single point t he wave is seen to pass as a single sharp depression more '_ r radual return to it. There is e o]ij>o>jte. positivi direction. The original level tei tial which luav be xero, or somewhat above or c wave of ]o\\- potential masked by 'he relative jiotential i- (il)served bet \\een two betv.-een which - greater than (lie total length of ' ab-iilu'e p tent ial at the nearer ]n >int ret urns rial potent ial 1 '< i re t he \\ a ve - if low potent ial ',' ' . I)'; 1 '];:'/ i In en 1 ire pa--a'_ r e of t he wave of low ; i chaiiire from t he original level a 1 ', :/' : I'elai ive potent ial is due simply to ' t he ',; - point . Similar! Y. t he passage of .' ' i '! ' factor in determining the [lotential at the first 1 ' ' '' ':! !> '\'e] oi equal potent ial . 1 ii I 'ig. _'!!_'. where the ''! ' '. not bei-ause t he absolute iiotent ial ELECTRICITY O('( UKKINCi IN ANIMALS AND PLANTS 270 is necessarily zero, but because the chart is 0110 of the relative potential of the nearer point as compared with the potential at the further point. The level marked () is the level at which there is no difference in poten- tial between the two points. The case in which superposition masks the wave of low potential is that in which the electrodes of the potentiometer are applied at poiins .so near together that the beginning of the wave of low potential reaches the further point before the \vave has completely passed the nearer point. The relative potential at the first point is determined partly by the change in absolute potential occurring there as the wave of low potential passes, and also by the change in absolute; potential at the further point. Fig. 203 shows the curve of relative potential, the heavy line being the actual curve. The dotted line shows the curve which would be formed under the influence of the wave of low potential at the first point alone. The interrupted line shows the curve of relative potential which would occur under the influence of the wave of low potential at the further point alone. At the beginning the wave of low potential is not masked, and the curve is due simply to the wave of low potential at the nearer point. Hut at a later period of time, represented by progress toward the right in the diagram, the curve is modified by Fig. 293. Masking of the wave of negative variation by superposition. the fact that the wave of low potential has readied the full her point. At any given time after this the actual relative potential at the nearer point is intermediate between the relatively low potential due to the wave of low potential at this point and the relatively high potential at this point duo to the wave of low potential at the further point. The result, as shown in the diagram, is thai a potentiometer whose specially prepared electrodes are at two points of the longitudinal surface of the nerve will show the wave of low potential as a sharp fall in relative potential at the nearer point, with an equally sharp recovery, but with only a slight deviation in the opposite direction, <>t relatively high potent ial. The second phase is st ill furt her reduced if t here is a material loss in power, as the wave of low potential progresses along the nerve (decremential current). Accordingly, an exceedingly sensitive galva- nometer. 1000 to 21. (KM) turns of very fine wire, connected with two points of the length of a nerve nearer together than the length oi tin* wave of low potential, would show the presence <>t a decided current in a direct ion from the further to the nearer point in the external circuit. followed by a much weaker current in the opposite direction. 1 In- direction nf the stronger current in the nerve 1 is away from the source of irritation and of the weaker current toward the point of irritation. Fig. 204 shows the direction of the current during the first phase f the wave of !"'' potential when the potential at the point nearer the sourcy t.t irritation has a lower potential than the furt her point . During the weaker second phase, described in the paragraphs immediately pre- i; the and >ign and the arrows indicating the direction of current would In- re\'ersed. Superposition of the negative wave or of the wa\'e of low potential u iuld produce a practically undirectional interrupted ctirrent through a nerve or muscle if a series of stimuli, such as the faradic current, applied, at intervals so short that the successive waves ot low [MO n' ial t rd upon i -aeli ' -t her s heels. T .-... narcosis, and degeneration make the recovery in potential ;,-- ali ipt ly retarding the return of the tissues to a normal : fter t!ie passage of the influence which has caused the tall in potential. The curve representing the passage of a wave ot low p ;,! consequent upon a single irritation would, accordingly, show ipt fall. Inn a much more gradual rise to the original level. \\ ;ii ' lences referred to were very marked, the fall in potential lie retarded. /.''.-' ; \iirrnticx n/nm \fi/utt'i~< \'f the nerve at regular intervals every minute, for example re- ih- ::. an equal negative variation, as shown bv the electrometer. -. the :' -ul' i'.ir muscular contraction becomes progressively less. , net; live variation in the nerve is closely associated with the tran-mis-ion of the nervous impulse. The fact thai no diminution in t he negative variation of the nerve leads to the conclusion ' " p a :.< :".' does not undergo a change m t ransmissibilit y in conse- it imje. 'I he lessened muscular font ract ion i- due, therefore. ' ' it! ' ' ' muscle Mself. v'l r\ portion of the wave and draws out the graphic 1 'al direction, while warmth ha-> a contrary effect. I'.o; ittau, both thi-s<- influence only the portion of the ' .vhich they are applied, not the other portions of ; r; i '. ' - and other- to be described arise in the various ' perton ance ol t he vi ilunta ry atn ! in\ olunt ary ' ble life. hi- only in cert ain except ional ' lie potent ial _ ' i . as to pn uluce It t hi il of appa rat US. The \ a rii dis elect ric ii i-'.-i-v, pp.i ice i-lect I'ic i| isclia I'ges \'i' >len1 enolltrh .-.,., |,.fe: . and to [.roduce a beuunibinn modified t! ' . t ne I-'..,-' : , plete retr,., ELKCTKHITY <)C( 'I' HKI.\<; IN ANIMALS AND PLANTS 281 i > as being set up in multiple scries. The voltage is sufficient to produ an electric shock, and the amperage is distinctly appreciable l>v th(; galvanometer (electromagnetic effect) or the voltameter (electrolytic effect). Currents of action occur in plants, especially in the sensitive plant and others which respond visibly to irritation. They are similar to those in animals, but the wave; of lo\v potential progresses more sloulv. The rate of progress of the wave of lo\v potential, not over ')() meters a second, and often very much less in the case of the current of action in plants or animals, does not indicate the rate of transmission of the same; electric current through the tissues. It simply corresponds with the changing position of the active electrode in the natural voltaic couple whose; electromotive force causes the current of action. Fig. 205 may serve to elucidate the matter. The velocity at which the current flows, possibly ISO, 000 miles a second, will not bo materially altered if the pair of electrodes are moved Fifi. 205. A zinc and a copper electrode are immersed at the points jc and r in a lout: trough of a liquid or gelatinous electrolyte and are connected l>y an external circuit which includes a galvanometer, ('hemic action takes place by which the /inc is attacked and becomes the negative pole of the resulting volt aic cell. The zinc becomes " negative '' to the copper in the sense that its potential outside of the liquid is lower than that of the copper, and the current in the external circuit is ~hown by the galvanometer to pass from the copper to the zinc. Of course, the current i.- continued through the electrolyte from the zinc to the copper. 1 through the electrolyte at the rate of a few yards a second to tin- posit ions ?/' and z. The analogy is very close. As in the case of the zinc electrode, the processes taking place at the area of !<>\v potential in the nerve or muscle are the cause of the electromotive force. Under the influence of a power inherent in living tissue this area of chemic or physical change advances from one part of the nerve or muscle to another, and so the point of origin of the electromotive force, or the negative wave. passes along the tissue. The position <>t the copper is ot consequence in determining the direction of the current from the zinc electrode through the electrolyte, and bv its distance, the amount of resistance. The same remarks are true of the ot her condition when t he wave of low potent iai is at one electrode. Local Currents of Action. The point at which an irritation is ap- plied undergoes a change" in potential \viiich is ot 1 inger or shorter dura- tion. It becomes "negative" to t he un irritated neighboring portions. It is dist inct from the progressive negative wave, and is also not to be ex- plained as merely an effect of polarization by the applicat ion for an elec- tric current, such as might occur at an electrode in an inorganic electro- 2X2 MKDK AI. KLKtTKieiTY AM) RONTGKN KAYS lyte. It follow- other stimuli besides electric ones, and is apparently a vital phenomenon. Waller, in n>0">. has described bla/.e currents or alterations in potential at points where the nerve or muscle has been killed by heat. ELECTROTONUS This is the name ^iveii to the condition of a nerve or muscle beyond and between the two electrodes when a voltaic current is applied to n portion of its length. ( 'uti In'troto/mx occurs in the portion nearest the c:\thode, and is characteri/ed by the flow of an electric current away from the portion included between the electrodes. Anelectro- t,,:. is occurs in the portion nearest the anode, and is characterized by the {low of an electric current toward the portion to which the buttery current is applied l>v the two electrodes. The portion "beyond the anode" has no reference to the idea of distal or proximal as regards the natural relation of the parts in the living animal. It simply means the |>:iri of the nerve or muscle nearest the anode, but not included between the cathode and the anode. Reference to Fig. 200. in which the litioii of catelectrotontis is indicated at r and of anelect rotonus at a, -.'.ill siiow that the current through the nerve in each case is in the same" direct ion as the bat tery current t h rough the portion of the nerve between Electrotonic Currents. These are vital phenomena, not merely ; '.' upon the effect which the battery current would produce in I . Lianic conductor oilt-ide of the part between the two '. ' Xeept between the electrodes the currents are the 'i would be produced l>\ electric diffusion ( Fi;. 207). .- current- in the direction -down in Fit--. "Jo."), 1 ppl '!' ]":, oj the battery current and coin inue They are different from the current of upplicat MI n| ;i volt aic ciiri'ent wi ndd ' -' : ' '1 ''' ';nd nf tliat apj.lication. Klectro- ti"'.u-ly in different part- of the nerve or 11 "' even cut in-l\ ilisappear at between the electrodes. The '' ' : ' '"i pro-rre.-ses in a wave-like manner. ELECTRICITY <)('( rUKIN<; IN ANIMALS AND PLANTS 283 so that it occurs first in the portion nearest the point of irritation and later in the portions further a\vav. While the current of action mav undergo sonic loss of po\ver at a distance from the stimulation, it is not anywhere near so great a loss as occurs with elect rotonir currents. The relative strength of aneleetrotonus and catelect rotonus varies in different animals, and is influenced by various conditions. I'mler ordinary circumstances they are about equal in man and other mammals. Positive After-fluctuation. After the disappearance of the local current which occurs as an area of low potential at the point of irritation of a nerve or muscle a condition of high potential is sometimes observed there (Hering), and to this the name of positive after-fluctuation has been given. This should be carefully distinguished from the second phase of the negative wave in the current of action where the potential is only relatively high, and which occurs under quite different conditions. These different currents have been described as a group of currents resulting from vital processes. They are not necessarily physiologic effects of electricity, although the application of the latter is one of the most convenient means of exciting these as well as other vital phenomena experimentally. Modifications in Electrotonus. Electrotonic currents do not pass bevond a ligature tied tightly around a nerve. . a/ Currenf Electrotonic phenomena are much diminished by anesthetics. Electrotonic currents do not immediately disappear when the current is turned off. but persist for a certain length of time with. oscillation both in the current strength and iti nervous conduct ihil it y. Electrotonic currents increase in intensity with the strength of the exciting current, and diminish very rapidly with the distance iroiu the portion between the electrodes (Fig. 'JOS . Physiologic Effects of Electrotonus. The excitability of the nerve is increased in the region of cat elect rot onus and diminished in that of anelect rotonus. This is true b"th beyond and between the electrodes. The diagram in Fiir. 20S shows the varied excitability of tin* nerve -greatest near the cathode ; md least near the anode. Excitability is very decidedly affected by electrotonus. Fig. 20s. r. indicates that at a point midway between the electrodes the excita- bility is unchanged. Proceeding toward and for a short distance beyond the negative electrode we find that the excitability progressively increases, and then beyond that point ii ai:ain diminishes to zero. Leaving the central oint, we find that the excitability is gradually "JM \i. I:LKCTKICITY AND reduced until after passing the positive electrode, and then gradually heci mies .:>T" ai^am. Klect rot onus inhibits nervous conduct Utility, so that stimulation of a :..'"! nerve at a proximal point will not traverse the portion between :._' t In- -t imulation i >l" a motor nerve bv a faradic current ; the impulse :. tin :. isclr because tin 1 condui'tion nf IUTVC excitabilit v is blocked b\ i-i ,'-" i ; i by a run-taut current applied between the faradized portion of the electrodes and cause conti'action of the muscle supplied by the nerve. < >r, i:' i; does so, it will be with reduced power (Fi.n. 200). l-'iji. IMO shws the effect of anelect mi onus in reducing nervous excitability. The nerve in this case is simply exposed, not cut out ol' ffj'-tffrsr-f rlTf-- cU xcitabilitv diminished bv aneleetrotonus. ["rtioii in which anelectrotonus is present is that vanic electrodes and The muscle, and to this part an The other faradic electrode is I 1 : ' "t 'he animal - bod\ . The presencr ' ; ' evii ubilii v. and make- >'' r ui usual in order to produce muscular ELECTRICITY OCCriiKINC IN ANIMALS AND PLANTS 285 Nerve blocking upon this principle is made use of in neuralgia. The anode is applied to the nerve and the current is ascending for sensory and descending for motor nerves. The increase of exr.it ability produced by catelectrotonus is illus- trated by Fig. 211. Electrotonus Explained on the Theory that the Nerve Acts as a Cored Conductor. It' t\\<> electrodes are applied to two points on ;i simple straight wire, as in Fig. 212, and the current be a continuous one. it will traverse only the portion of the wire between the two elec- trodes, and in a direction from the positive to the negative electrode. It is different, however, if the wire be immersed in a trough of salt solution, which is a much poorer conductor of electricity than the wire (Fig. 21.3). A part of the current will pass from one electrode to the other through the liquid alone. Another part of the current traced from the positive electrode will be found to go through the liquid to the nearest part of the wire, and follow this good conducting path toward the other electrode. Other portions of the current radiate from the positive electrode.- through the liquid in every direction, and reach different points on the wire some on the portion beyond the positive electrode, others between the two electrodes, but practically none beyond the negative electrode. As we shall see later, tjie current or the electric pressure, in the liquid is in the opposite direction beyond that point. The current Hows in the same direction through every portion of the wire. In the portion beyond the positive electrode currents entering the wire at any point find the best conducting path through the wire toward the negative electrode. In the portion between the two elec- trodes the best conducting path is through the wire toward the negative ! ijr. I'll'. Conduction through a simple wire when electrodes are applied laterally. electrode. But, of course, at every point some current is escaping from the wire to pass through the liquid to the negative electrode. The same escape of the current from the wire through the liquid to the negative electrode takes place at every point beyond the negative electrode, and this enables tin; current to traverse the wire in the original direction right to ihe end. The escape of current to or from the wire is greatest at points close to the electrodes where the force of attraction by the oppo- site polarity is greatest, and it is least at pointvS far away from either elec- trode, where the attraction is very much weakened by the resistance of the liquid through which the current must pass. I nder the conditions of the experiment the only current which can pass through the wire is that which enters and leaves it through the liquid. Consequently, the current through the wire is strongest between the electrodes and near them, and becomes very weak at a distance from them, though it always flows in the same direction. If it proves to be true, it will illustrate in a crude manner that the phenomena of electrotonus may be explained upon the theory that they are due to the nerve acting as a cored con- ductor (Kernleiter, in (lermaiO. An experiment has been actually performed by J. Sosnowski 1 with a copper wire embedded in a bar of carbon. The phenomena of elec- 1 (Vntr;ilbl:itt. f. Physiologic, \i\. >'>. April 22, I'.tO.I. 286 MKDICAL ELECTRICITY AND RONTGEN RAYS trotonic currents were duplicated, and his conclusion was that elect ro- tonu- i- -implv a mailer of difference in conductivity, and not of polar- i/at ii 'ii i >r vital pri icesses. Hermann's theory is i hat elect rot onus is due to polarization between the a\i.--c\ linder and tin- my el in sheat h. The same diagram (Fiji. 213) ui:i\ M-rve i.i illustrate this if \ve suppose the fluid to he a solution of . Hi . inc. i he elect r<>des to he i>t' /inc. and consequently impolariz- able ii and the wire oi' platinum. This is an experiment heeii tried, with the result that currents are found i ' , \ through all parts of the wire .simultaneously and in the same i-.. Tin explanation offered is that there is a polarization of the [>] . which prevents all the current from passing directly iiductor. Wire in a troueh of \vatcr. : from the nlatintim and the nearest electrode; and this causes a : the current through the liquid to the nn >]<.> distant parts T.HE CAUSE OF ANIMAL ELECTRICITY: AN EXAMPLE OF A CONCENTRA- TION CELL v<> portions of liquid containing an electrolytic salt in different - ': conri-ii? rat ion and separated by a permeable or a "semi- membrane form a cnnct-tit ration con bv 1 placed in each portion of fluid, an electric current will ' Ic i-uit . connect inir t he 1 wo. - ' " !iat \'iial electric curi'ents are ]>roduce(l in this 1 he ordinary processes account for differences in enever there is a dividing membrane. Hut the 'pment ol a difference in potential at a particular "1 ' ' p - in sp.ite of t he many import ant I-'" 1 ." .. Tschagowet/. :i ()ker-Hlom, 4 and Hoi ut i an. 7 besides the earlier classic ' ' ' ' ' . ' ' .' and a host of others. 1 ' c ' I'anslal i-i ; from Morui t au. who has - collated the most recent >sue- can only be considered i I ' ,ii- ;i rii,m- i.C tlic |{ () y:il Society of ELECTRICITY OCCURRING IN ANIMALS AND PLANTS 287 principally as produced by concentration cells since no metals are present. Their comparative constancy as well as our knowledge of the structure of the tissues make it necessary to assume that the two elec- trolytes with different degrees of concentration are separated by a 'semiperrneable' membrane. This allows one kind of ions to pass through it, but not the other ions, which consequently accumulate upon it (Ostwald, 1S90). "By 'membrane' is generally to be understood the outer and limiting layer of living substance of the simple tissue elements: the ectoplasm, or the cell-membrane, or the sheath structure, such as the sarcolemma, nerve-sheath, etc. A difference in concentration is present upon the two sides of this membrane when elect ric currents are produced by irritation or natural activity. This may be referred to as increased 'dissimilation' (retrograde tissue change or disintegration) at the point of injury, death of tissue, or irritation. Stimulation is produced in the substance inside of the cell-wall, not in the outer, intercellular fluid. It will be remembered that the irritated place always becomes 'negative ' in the same sense as the zinc in a voltaic cell (really electropositive). Consequently, it must be negatively charged ions or anions (ions which travel toward the anode) that are liberated by the increased retrograde tissue changes and press upon the limiting membrane from the inside of the tissue-cell which is impervious to them. The positively charged ions or cations liberated at the same time are free to pass in every direction from the altered place, passing readily through the cell-mem- brane into the enveloping liquid, described below. "It must be remembered that free acid results from the death or activity of muscle or other tissue, and Waller and Boruttau have called attention to the fact that various modifications of the current of action in nerves during activity are analogous to those resulting from the action of carbonic acid. Tschagowetz has attempted to calculate the electro- motive force 1 from the probable concentration of the carbonic acid in the tissue-cells, and found an electromotive force corresponding quite closely with the observed electromotive force. "But the process can hardly be as simple as would be represented by the mere 1 statement, that II cations are freely movable, while the CO., anions cannot pass through the limiting membrane. Living albumin contains, for example, alkaline salts in loose combination, and it seems capable of itself acting as an organic acid. And by its disinte- gration metallic, ions may appear as cation- and complicated albu- minoid products as anions. which, on account of their complex molecular structure 4 , cannot pass through the 'membrane.' Then, again, a demonstrable acidification does not necessarily indicate 1 an actual excess of II ions. "Waller, in his book ' Kenn/eichen des I.ebens' ('Characteristic Kvidences of Life'), goes somewhat too far in speaking of an (electric) solution pressure (or osmotic pressure' of the protoplasm, llns expression has so far been applied only to metallic salts; and. besides, that it wotdd be necessary to limit it to the cations. "The 'positivity' for, more properly, 'electronegative behavior > accompanying increased assimilation, as in the positive after-fluctuation and in anele'Ct rot onus. etc.. can be explained only on the theory that MKDH AL KLKlTKU'ITY AND KONTGKN RAYS. tiu- local concentration is diminished by the .-ynthetic process, or that the cation- which do pa-- through the 'membrane' are repelled in eon- .-equeiice of tiie proximity of an anode. "Oker-Blom and Macponald. besides Tschagowetz, have sought ',i find ;: ; litional evidence in favor of the concentration cell theory as accounting for the demarcation current. 1 They applied different h \-p.it : h\ pert on ic -ol u I ions to a muscle and to us t raiisversely cut vir'ace. and t hen tested t lie d ilTerei;ce in potential, using unpolarix- :ible >. t >ker-Blotu concludes that the concentration cell arisi - : : mi t he alterat iou m i he t issue; while Mac Don aid and Bernstein [e that a difference in concentration was previously existent be-weeii the |>rot oplastn and t he enveloping tluid and when there is an iis difference in concentration is conducted at onlv one place, [ . mil : - niedi mi of i he ' men i bra ne.' Hot li of tliese aut hors prefer ue ' theorv to the alteration theor\ ^ But this cannot satis- ;': ct >rilv account for the current of action inlluenced. a> it is by narcosis tat imie. "The theory of a protoplasmic limiting 'membrane' is of funda- ::..;,'. ini])onance in accounting for local differences in potential. - fi ' . mjurv. secretion cui'rents. blaxe currents, and it is also !iecc>sar\ in the case of everv extension and progress of differences in ic potential where the alteration theory alone is insufficient " I' is necessary to assume the existence, besides the limiting ' mein- .' of an enveloping liquid, which normally is isosmotic with the eel] contents. There are also librillary structures which conduct inscle tibrilla in the sarcoplasma, netirofibrilla in the axis- ; ." liquid, etc. There are, consequently, structures which possess a cert am analogy t . . t he polarized nuclear conduct ing models wilich were much used, as in demonst rat ions of t he elect rot on ic currents iii nerves, etc. The r< semblance is to t he extent that the local equaliza- . >n o] concent rat ion difference and of potent ial difference (local current i thin^ i i t ake place in the adjacent t issue, etc. In other - Hieor\ oi nuclear conducting libnlla and a limiting mem- n\'elopmg liquid explains the wave-like progress of the . I he con current wave of contract ion. and probably 'irn-ss oi tissue chaiiires. The limiting meml)rane theory 11 ' lieory, S. T.) furnishes t he key to the understanding >n ! stimuli upon elect I'ochemic principles. r ' be said here about the mat ln i niat if calculations, :. only polarixecl nuclear fniiiluctiirs of IFer- f'remt-r. but they an- still in an incomplete state. ol the extrapolar elect rot (inic currents is dhvctlv ft ract ion or repnlsioji of the ions of the envelop- 1 '''". elecll'ode- ;ilid t 1 ie -e m i] M -1'lliea b] e cl i a fact el' i he ii ore resist ani i- i he membrane, t he - greatest in m(-dullated nerves, and least in Significance of the "Alteration Negativity." "Regions of become 'negative' m consequent' ,,f the ELECTRICITY OCCURRING IX ANIMALS AND PLANTS 2x<) greater permeability of the limiting membrane to the cation.- than to the anionic part of disintegration. This has a clo>e relation to the general laws governing electrical stimulation.'' Tchiriev's Results in the Study of Muscular Currents. A mosi accurate and complete series of elect roinetl'ic measurements recorded photographically has been made by S. Tchii'iev at Kiev. Kussia. 1 and his conclusions are worthy ot consideration. One of his photographic recnrds is reproduced in Fig. 214. Three tracings are shown: d. registering tlie time, each ascent and descent lasting ()..'-> 75 second; /;. the myogra])hic curve; and c, the elect roinet He curve. The gastrocnemius muscle of a i'rog was not detached and tin- blood circulation was undisturbed, but the muscle was more or le.-s injured in connecting it with the myograph. Two non-polarizable electrodes connected the muscle with the capillary electrometer which showed a current of rest equal to 0.105 volts. This was compensated according to duBois-Ileymnml's method. The sciatic nerve was stimulated /'// .W/// by isolated induction shocks ('cur- rents from an induction coil produced the opening and closing of the primary current) at the rate of 11 opening shocks a second. The myograph indicates an incomplete rhythmic tetanus. _: stimulation l>v isolati'il ini luc- Fic. L'14. Mvographic and electromofrii 1 r-urvrs ilunns: The elect ro'metl'ic curve which is the special subject of th.is study does not show itself like the teeth of a comli as dnHois-Reymond sup- posed. I'nder the influence of each stimulation a wave of negative electrical potential traverses the muscle and the waves >t negative varia- tion succeed each other s< > rapidly \vith stimuli applied at tin- rate mentioned that they overlap. The potential or voltage has not nearly reached the zero point before the next \vave arrives, 1 he I'esull curve somewhat resembling :i (iigln ni - ;-. The vertical distances in the chart marked o. 10. 20. and up to ion :t re millivolts. The elect roineiric curve i- sometime- like the teeth of a saw. The potential is sometimes reverst-d - i 'he curve is belo\v tin axi of abscissas instead of ab . vt>l. vii. p. .V.i: . 19 MKDK Al. KLK< TKH ITY AM) KOXTGEN KAYS The various photograph- corroltorale Ilelmholt x's and Bezold's oh.MTvati'iii that the negative variation in the muscle begin- before the rnu.-cular linn. I'.ach negative wave lasts longer than the contraction which accompanies it, and torms a continuous rlir\ e with t he Micceei ln.g \\ a\"e. !"., in- .,._':. phjc ! . : e falls ver\ rapid! v alter shutting off a current . : [elanus. iiut the elect rometric curve may even >ho\\ an immediate rise, and it.- fall is always slow and gradual. : ,, - coiiclu-i"n iii regard t" muscular currents is that negative and : '.- .. n - 'litraction dn not depend upon one another, : , , ipMi ; nmmn caiisi I he st imulation of the muscle. Tchiriev's Conclusions in Regard to Bio-electric Currents. i . 1'he living ai ; perfect ]\ in t act t issues and organs, for exam [tie, nerve, rt . d" not show even slight currents or difference in r . ; jicissihlv be considered as playing a role in the i] i heii functions or in t he activities of the general system. _'. 1'he --:.: ,e tissues show a difference in potential when they are i ired pan is negative to the uninjured part. The it - rf ace of a muscle or a nerve is negat ive to t he longi- . ;: : t lie tillers. :;. Tiie .mirces of this elect roinot i\'e force are preexistenl in the .--.<-. This is shown hy (n ) The difference in potential when injured: the various phenomena of elect rot onus; (r) the electric organs of : in fishes. I. Sn mu la t ide o| production of this negative variation seems to be sniin-es of electromotive force undergo a change in ill act inure feeblv. This depeniU upon a 'tiseOjUenlly muscle, on account of rigor mortis. '^ ' '" '.'anal ion when stimulated; but nerve in and negative variation are independent of ; '''I ;iloi!L r intact ner\'e-fibers independ- piitenl ial. There is no elect ric rtace Hi i he in t act brain when i'i d. 'he iH'rve supplying an uninjured 1 ' ' its c] rcnla t ic >n un im- ' ' c irrei is. There may be ' e' anus. I here i- en her no elect He change or / ..; le^ tha:, n.nul millivolt. I". M-; , ' ,. i, r,-,, ELECTRICITY OC( I'KRINq IN ANIMALS AND PLANTS 291 been flowing for a long time. The result in any of those cases is a tetanic contraction of longer or shorter duration. Tho electrocardiogram is a graphic tracing of the electric currents produced by the contraction of the heart muscles; has become an im- portant factor in cardiovascular diagnosis. (See page :>2;V) 11. Spontaneous tetanus and tetanus as seen in voluntary muscular contraction is a complete non-rhythmic continuous contraction. Rhythmic tetanus is produced only by rhythmic stimulation of t,he nerve or muscle. 12. An injured muscle giving a current of rest may be caused bv rhythmic stimulation to exhibit marked steps or dentitions in the electromet ric curve of the negative; variation. This may produce tetanic contraction in muscles of the other leg whose; nerve has been placed along this muscle, just as if the stimulated muscle yielded a faradic current. b>. Injured tissues and organs, ('specially muscles and nerves, show certain electromotive changes when performing physiologic functions, but it does not follow that these electric properties which are inherent in the tissues take any more direct part in physiologic aetivitv than the other physical and chemic properties of the tissues. 14. Kleet rot onus of a nerve is not a process of polarization in the ordinary sense in which that takes place in inorganic substances, }>ut '* due to a displacement of the sources of electromotive force in the n'rfVe itself under the influence of the constant current. These are the deliberately formed opinions of a man who has made wonderfully careful measurements of the actual electric conditions accompanying physiologic activity. He does not think that under normal conditions there are electric currents of sufficient intensity to be the causative factor in physiologic adivitv. He thinks that the infinitesimal currents which are normallv present are only a part of the general chemic and physical changes occurring in living tissues, and are not the sole and regulating causes of activity. According to his view. physiologic currents of electricity are phenomena, not causative factors of muscular contraction and of transmission of nervous stimulation. If these views are correct, it would still remain true that elec- tricity artificially applied is one of the most effective means of exciting physiologic activity. PHYSIOLOGIC EFFECTS OF ELECTRICITY PHYSIOLOGIC EFFECTS OF ELECTRICITY UPON MICROORGANISMS Galvanotaxis en , current of electricity passes through a ;m isUall' small living organisms tend to move '.' electrode under the influence of the current. ft-: ; . > ; ; living organism to arrange its. -If so that its long a\i- ::. relation, either parallel or at a right angle to the direction of the current, i- called ciahnnotaxis. It is analogous to ;< v.;<,\ in \\\ : . i. a shoal of small fishes will all head the same way. swimming anain-t the current which is carrying them along in a brook. Ti - i-operties ;;iv exhibited by living organisms of different sixes. c insist of only a single cell. 1'rotoxoa. infusoria, . ip h - ''. v n used in many experiments. ms to permit of a purely physicochemic explanation :;- :.ecess ;! ;-il\ :i \:';;1 phelii itnelion. A cell n iay act |U ire an elect 1'ic ifg" ' unequal peneti. ition of ions of different sixes (positive ' 'Ugh its enveloping membrane. This depends upon r cter of 1 h'.- membrane, and the osmotic pressure ' !! of t he posit ive or negative ions inside the ' - '' :'!. ' !< solut ion in which it lies. A cell which has :>->s!?ivc electric charge '.vili be attracted toward the ' . and one with a negative charge will tend to move !>"s':tivi elr-rtrode. A. Coehm and \\'. Barrott 1 have studied '." ' ' galvannt axis from this point of view. 1'aramecia. i:.:'us,,ria, -wim toward the cathode when in a dilute ;. Hut r is not so simple a matter with 11-1, ials, where the central nervous system \ '.": us n its' lie calleil into pla\\ Galvanotropism : still more complicated, and seems decidedly tissues and not a mere physical effect ''" matter. It is the growth or bending of a living th ;i galvanic current . It may be house-plant toward a lighted window. The - ' and 1 idlof'i ha\'e been supplemented by li-hing between galvanotrojiism " pn upon infusoria from chemic changes les. I'. r any purelv physical theory. It is noteworthy, however, that inorganic particles may exhibit motion under the influence of the same current , and this is sometimes, in the opposite direction from that taken by prtoxoa. Microorganisms undergo changes in shape and consistence under the influence of an electric current passing through the medium in which they lie. The ameba puts <>ut projections from the cell-body, pseudo- podia, toward the anode, ami undergoes granular degeneration when too strong a current is applied. It appears to the author that these different phenomena have partly a physical and partly a physiologic basis: that there are the direct effects of ionizutiou, secondary chemic changes, cataphnresis, and heat upon the substance of the organisms, as well as the indiivct effects excited in the organism by these actions of the electric current. Schatzki 1 has experimented with a variety of pathogenic micro- organisms, especially noting the effect at a distance from both poles. He found that galvanic currents of from L'o to :;o milliamperes, applied for from one and one-half to two hours, completely abolished the virulence of these microbes; succeeding generations from microbes thus galvanized possessed less vitality as to virulence, as to activity, and as to growth. The medium through \\hiVh the current was passed was contained in a glass tube 1 cm. in diameter and 'JO cm. long. PHYSIOLOGIC EFFECTS UPON VERTEBRATE ANIMALS The most important part of th' 1 effect uf low-tension currents up to 110 volts is upon the heart. There is a fibrillary tremor, an irregular fluttering of the ventricles, \vhile the auricles continue to beat regularly. This has been studied by applying induced currents to the exposed heart of different animals. The exposed heart of a dog never regains its rhythmic beat after fibrillary tremor has been caused bv induced currents. The exposed heart in an adult guinea-pig can be revive' I with difficulty by cardiac massage and artificial respiration. A rabbit's heart usually revives spontaneously. The rat's heart revives as si mil as t he current is turned . >t'i . There is the same effect upon the heart when low-tension alternating currents are applied to the un<>| erati t : h rough in out h and rectal elect rodes. The electric resistance in a dog weighing twelve to twenty-foiii pounds is from 'J">o to :!.~>o ohn s, ; Iternating current of/' fr f<)} MKDICAL KLKCTKieiTY AND RONTGEN RAYS Ten volt- for ten second- -onietimes interrupts the cardiac rhythm and -ometime- causes fibrillary tremor of the heart and death. Ten volt- for two seconds, with the pneumogastric nerve severed, caii-e- death by fibrillary tremor of the heart. Ue-piratioii i- interfered with in all the above cases by a general nmdiiion of mu-ciilar contraction, -tetanus, but becomes reestab- lished as soon as the current is turned off. Respiration gradually fails ran is permanent 1 v paralyzed. \. . , UK ,-urrent of ti-om 20 to 40 volts produces the same fatal ... ,i requires onh a second or two of contact. Convulsions are - ,[,[, , ; ;in ,l the animal is in opisthotonos or generalized tetanus lasting five -ecunds after the current is turned oiY, and followed by clonic (HI. us which irradually cease. Respiration which has been ,,, d > , i lie tetanic coi it ract ion recovers and continues for quite if time. Sensation is not much affected. The corneal reflex is pi-i-erved. Death results from almost instant cardiac paralysis, but , other functions of the living organism continue for a time and lallv die nut as a secondary consequence of the failure of the ,\n ; It i a ting current of from si) to 120 volts applied by electrodes . ipoi the shaven head and the shaven left thiirh for at least one iduce the same results as have just been described for currents ill 20 ' i (| volts. The resistance in the case of electrodes upon the md 1 hiirh is li H I i ihms. Tiie paralvsis of the heart occurs at once in all these cases, but the ; i! l-pressure shows an initial elevation, followed by a trradual decline. Pi ' \ - and Hattelli attribute this to vasomotoi 1 stimulation in both arteries and veins, -lowing the passage of blood through the arteries the heart, and pressing it through the veins toward the heart. The thorax bem^ opened, the ventricles are seen in some cases to late of fibrillary tremor, while t he auricles beat regularly for v lift een minutes. alone does IK it do any good, but cardiac massag< pi rat ion combine, 1 keep t he animal alive as long as t hey :. Dunn'.; this period sensibilitv is normal. \ '.. ' tpplied by electrodes placed upon the two sides of the i! !' : ; a resistance of '_N) in .'ii'D ohms. Ten volts applied me do'_ r . while two others survived. <>ne of the : c irn r . ' o| I .") vn|ts applied for five seconds. 'tended i he application of the electrodes to both Summary of the Effects of Low-tension Alternating Currents up to 120 Volt:-'. ! ' . are >li<_rii! /,, / ,,,,,.- ,i;.-.-tnrhl I \'i -. The effer! upon ! he fndft is to ; :'' : . - previously explained, is fatal in : '-co 1 i red : I'oin in nt hers. // .- [linilioi} is not 1 : i-rs or Liuiiu a-pigs, and in PHYSIOLOGIC EFFECTS OF ELECTRICITY 20") the electrodes. This is the- e-ase 1 when one- elee-trejde is applieel to the animal's head and the- other to the thigh, or when one is placed over t he- cardiac region. Preliminary section of the pneunmgastric nerve has no effect upon the 1 production of fibrillarv tremor. Batte-lli considers it probable that fatal effects from low-tension currents in man are; produced in the- wav de-tailed above, vi/.. bv primarv cardiac paralysis. The Effect of High-tension Currents. A current of 20 volts in the e-ase of the rabbit, or ">")() volts in dogs, doe-s not produce fibrillarv tre-mor of the- he-art or death by primary cardiac paralysis. There- is only a te-mporary arrest of the auricles from stimulation of the- pneumo- gastric nerve. Respiration, on the contrary, is impaired by an effect upon the respiratory center in the medulla. This effect may varv in elegree. Respiration may be- spontaneously renewed after the current has ceased, or, if it doe-snot ret urn of itself, it may be readily brought about by artificial respiration. Shocks from currents of this voltage are not ordinarily fatal if the proper treatment, artificial respiration, is applied. The Effect of Very High-tension Currents. Currents of from 1000 te> 10.000 volts, as cmploye-d in the long-distance- transmission of poAver, produce; mechanic lesions of the tissues traversed, just as light- ning does. Fatal hemorrhages in the substance- of the- central nervous system may cause irreparable paralysis of respiration and other functions (Jellinek). The;se very high-tension currents are- often instantly fatal, but the; e-ffect varies greatly 'with the path traversed by the current in passing through the body. If the heart and the central nervous system are 1 not in the direct path of the; curre-nt , t hey may rece-ive only a fract ion of the' original current, and the effect may correspond tot hat of a medium or low voltage. The- reve-rse is true as to low-tension curn-nts applied directly to vital organs. From 90 to 11") volts have killed men by cardiac paralysis under exceptiemal conditions as to electric conduction. On the- other hand, in a case- which came to my own knowledge, a shock from a 2200-Voll alternating current was survived, with no permanent damage- e-xcept a dee-ply grooved scar of the; hand and a fairly well-united fracture ot the femur. Legal electrocution bv means of an alternating current of from l.'!()0 to 1700 volts is not always immediately fatal, because- it aims to produce respirator}" paralysis, and it some-times requires three or tour applications to make this paralysis permanent. 1'revost's animal experiments show that a heart in which fibrillarv tremor has been induced by a current of .">( i volts may sometimes be reanimated by a current of -isoo volts applied ten seconds later. This is not to be recommended in the- treatment of human beings shocked bv The Relation of Amperage and Voltage to the Physiologic Effect. -Industrial currents for linht and power, if alternating, usually have about ")0 periods a second, and this rate is very active 1 physiolog- icallv. These- e-urrents have- such tremendous volume 1 that contact with a conductor carrying a current "i' MUioi) volts must be absolute!} guarded atiainst. Xo person must be allowed to approach within sparking distance of such a conelue-tor. :md no other conductor must be allowed to touch it or come near it. The crnx*inuppo>ed to carry a perfectly harmless - :i frequent caii.-e of fatal accidents. These industrial currents sending a fatal number of amperes or too large a quantity [iil'ii ;-:. [] e resistance offered by the animal body. Harmlessness of High-tension Therapeutic Applications. :.. :;_ai:. the very rapidly oscillating high-tension Tesla currents ieca IM' i he I raiisinission of ions through t he se mi] >er meal >le H) tin- electrically conducting human body cannot keep up . and so only a part of the potential variations affects THE EFFECT OF ELECTRICITY UPON ANIMAL TISSUES :"<- vary with the voltage and amperage of the current ;. and also with its density and direction. They are very largely -is. and. as in the case of an ordinary electrolytic cell, ':. evident ;.: the points of contact with the electrodes. This he moiv certain to be the case because of the wide diffusion of ' i) the tissues between the t \Vo electrodes. Sometimes the I im: effect of ;;li elect ric discharge is produced in the '>,- ' is :. .-t he quite exceptional. Lightning splits a great p ' i bottom by an explosive effect due to the heating of air . ;:pof and ' he iraseous products of elect roly sis in the cellular re <>: ''.< .'. 1. Such an effect is not produced upon men or n iizhtning stroke. The human body is quite a good <: : electricity as c-ompared \vitli the insulating properties of \) . '' tMii'i'ent can pass through any part of the body or bout eijiial readiness, whereas in a tree there may LT ti'aci.s lilled \vith real'oduce f. a -Ul'l ace elect l'( (lie 'ir\' t'roin accident al i ie burns which >ub' <> due chiefly i ily a very electrolysis. i . " ; '.. : ,:'. e a direct ' ' ' <' . added to the 1 ' plalinum liar '.va v. 1 lies. !v - ;-. !: : : 1,, eject n'citv the PHYSIOLOGIC EFFECTS OF ELECTRICITY 207 animal body may be considered as an electrolyte consisting of a >ponstte becomes white ami swollen, and bubbles of uas are formed. 1 he cheinic effect at the negative electrode is of the liberation of // and "f Oil. or "f free alkali, and this has a dissolving action upon albuminoid substances. It the action is long enough and strong enough, there is colliquativo necrosis of the tissue surrounding the needle, and the latter becomes loosened, and when removed is found bright and free from nxid. A needle electrode connected with the positive electrode produces a somewhat similar effect upon the tissues swelling and bubbles of gas. hut oxygen and free aci ysis there. The result is a coagulation necrosis (from the formation of acid albumin), and the needle st icks fast in i he tissues. A st eel needle should never be used as an anode; the iron ion would stain the sk n indeliblv. Such a needle would COM..' out badly rusted from oxid; I With surface electrodes 'here is a swelling and edematous condition > \ the skin under the cathode, due to electrolysis, and this may be correctly called cataphorescence. At ''.' anode, on the contrary, '' skin has a tendency to contrac The tissues of the body for uniform electrolyte when spon Hi a:v u.-ed. and the products ut' electrolysis arc found at first K -all solution clo-e to tin- electrodes. If the current continues ; rect ion, a secondary effect becomes evident after a time. Tin? u' ::;' re- 1st a nee at I he surface of t lie body and the complex character of ;- cjn-n ic composition make the point of contact between the salt >o] itj !! and the skin correspond closely with the line of separation between tle water and the salt solution in the experiment below. or alkaline radicles are liberated at the surface of the skin, and may produce a severe effect. .Means of avoiding this are by changing the direction of the current from time to time, and by occasional!} rii simi out the electrode with fresh solution. The palms of the hand are most resistant to any such effect, but the skin of any region where t he ep idem i is is thin may be irrit a ted or even "burnt " by the products dmlvsis. This is one reason tor the employment ot very large electrodes when strong currents are to be applied. A given strength of current expressed in milliamperes will produce the same amount of .-.:.::' whether it pas.-es through a large or a small conducting When the surface of contact with the skin is a large one, the .--edion of the conducting path is correspondingly large, and the '- if the chemic changes are so diluted that they may be carried the circulation of the blood and lymph without producing an ' ' ' :.';LT local effect. The : alter is one of current density, and is similar to the difference '' een the -low combustion which takes place in the whole human ii ; : produces a certain amount of carbonic acid (CO.,) each .' I'ai-im: the temperature above i) s >.."> F. The same i ' of combust ion producing t he same amount of ('()., per minute in .- fintrer-t ip would be accompanied by a painful and destructive itli a local temperature far above the normal. \n example oi secondary actions is found when an electric current - 'I 1 i' ion of sulphate of copper. The salt is separated - deposited as copper plating upon the surface of ' electrode, and ;iu acid radicle which goes to the positive adiHe combines with the hydrogen of the water ' oi copper ;- dissolved, and forms sulphuric acid. '1 the ater i- liberated as bubbles of gas. Klectrol- 'e .it -odium tui'inshes the same secondary the formation of sulphuric acid and the secondary action takes place at the owerful affinities that metallic sodium e. l)in it at once coml)ines with the iri'l idi- liberate- bubbles of hydrogen tras. " i 'i " ' ' ' ' prima ry pi-i .ducts are capable 1 ' li-l lice of 1 he elect rodes. v-i- appear only at the electrodes and t he lat 1 er is homo- currenl has to traverse ' foul ainiiiir t >lain water ' 'In- bottom, the whole ' ' '-'I rent pas-es from above down- ' liquids, indi- i'l- I' 1 ' 1 -'' cm n t:' v, ill result in PHYSIOLOGIC KFFKCTS OK KI.KCTHICIT Y 2W a bine color, indicating the liberation of a base or an alkali at the junct ion of the two liquids. J'olarizdtion also takes place at the line of separation between tin- two liquids, and may be demonstrated if the original electrodes are removed alter the current has been flowing for some time. The original electrodes may be removed, and another pair which are connected with a galvanometer may be placed in the two liquids. A current will at once begin to flow in the contrary direction to the original current. Transportation of M fitter />// the Electric ('nrrc'ni. A solution of sulphate of copper in a glass vessel and an inner porous jar will tend to assume the same level in both of the jars, but if copper electrodes un- placed in the two jars and a current of electricity sent through them, the liquid will be carried toward the positive pole, and will assume a higher level in that jar than in the other. The stronger the current, the greater the difference in level will be maintained. Another striking demonstration is made by passing a current of elec- tricity through two jars containing an anilin dye, and between which is an inverted U-shaped tube filled with gelatin which dips into both ]t\r>. Kven a weak current will cause a rapid ascent of particles of the coloring- matter into one or the other arm of the U-shaped tube. Salts which are present in very small amount or which are sub- jected to a very weak current are not always dissociated, but are sometimes merely transported by the current in the ways illustrated above. In the living tissues, as in experiments upon electrolytic solutions in glass jars, the products of chemic dissociation appear only at tin- elect rodes. In the animal body the current does not pass through a single homogeneous electrolyte between the two electrodes, but encoun- ters membranous septa, either large or minute, which convert the path of the current into the equivalent of a series of electrolytic cells. An experiment has been tried by Leduc. placing a rabbit in con- nection with an anode moistened with strychnin sulphate, and another rabbit with a cathode also wet with a solution of strychnin sulphate, the two rabbits being joined by strands of wet gauze, \\hen the current is turned on chlorions (chlorin anions) pass from the tissue- into tin 1 solution forming the anode, and strychnin cations pass from the solution at the anode into that rabbit, which accordingly develops strychnin-poisoning. The other rabbit connected with the cathode experiences only the effect of sillphions (SO, anions) from the cathode solution of strychnin sulphate, and of sodions (sodium cations) liberated in the tissues and traveling toward the cathode. Using potassium cyan id solution for 1 he two electrodes, a similar effect is noted, but upon just t he opposite rabbits. I Fere t he toxic ions are cyanogen anions. and penetrate the tissues from the cathode solution. A similar condition is found in t he animal body, and the free products of electrolysis appear only at the electrodes, but there are complex chemic processes which result in the neutralization ot the metallic ions by combination with tissue elements near the anode, and it is the sann wav with acid ions near the cathode if that electrode is moistened with an acid or a salt solution. The ions derived from either electrode d" not pass through the body to the other electrode, but enter into com- bination with certain tissue ions, and other tissue ions liberated t r - m these pass through the body toward the other electrode. The body, ,-. far as tlir conduction "i electricitv is concerned, may he regarded ;, a mass n| siihni'Hi ni sodium ch lurid '^. looo. and according to many ,':,. rvers con . u [> nlv hv electfolvsis and not at all by the sort of passage of simple electrons, \vhieli is characteristic tals. Thi ran thai electricity can travel through the ,- a rate no! exceeding ."'.' meters a second, instead ot at the rate ,,:' IM 1. 1 it in miles a second. This retardation involves the con version t - surelv as is the case with mechanic motion - heat, and the remainder acts to produce r con in or decomposition. A current passed through an .-I U .; a jai in '"" li'jiiids are separated hy a. permeable - . '::>'' ,e;tl)le UK i ibi'aiif expends a pan of its energy in adding : re ; ardiiii: 'he motion i particles through the membrane. A . ,} i-lec; ;-ici: \ \-jelds all these dil'ferent forms of eiiergy in passing . i: :, I) idy. I; increases or reduces all the phenomena -s ies accoi'ding to the direction of the current and its mode \ |i '. niijed application probably produces chemic >'!> places ::. the path between the electrodes, as well as . >-e ci 1'itaci wit h them. \: . '._ H [ire.-t .-' - "i' electrolysis are the destruction of the :'o icj.- in liypei't richosis and of unnatural growths of various . ;-. : ' 'tion of various materials, anesthetic and thera- Coagulation Caused by Electricity.-- IVoteid matter is coagulated 'urrent<. [experiments by \\". H. Hardy 1 were made with i'o |i , -o] it ion of eir-albunien and a current of from 10 1 '" '.-/-. b-ii n! >n]y ]fl ! 1)M milliampi-re. When the solution was /'re carried toward the anode, with ' ' ' ipale.scelice ;i! .,| :( c (( aLrulum there. The Same ' "..: ' t he cat hode when t he soli it ion was acid. Effect Upon the Blood. -The experiments of ('. X. Stewart- have ' ' ffeci i] 'led ricity u|on the lilood. The ct m- h ha- dissolvi-il out the hemoglobin of the - : : '" a greater extent than at other times. ' ains henioirli >hin and ni is . -i u'oo,] conductor of electricit\') '_ ': 'bill alone is i lissi (h'eil out , 1 '' 'i ' '.' . lid t he elect n ilvtes. ' '! 'am more >.j ....,- than can be < lissi >1 ve< 1 ' ~ee;i!S probable 1'HYSIOI. <)<;ir KFFKCTS OF KLK( r l 'UK 'IT V '.',()} that of the entire blood will give an indication of the fraction which the blood-cells form of the entire blond. This may be of value in r-< in- junction with the usual test, which is based upon the color of diluted blood, and especially when the apparatus for making the latter te.it is not available. The Effect of Electrolysis Upon the Resistance of the Body. After the current has been flowing for a certain time the resistance is quite different from, and usually much less than, the initial resist- ance. This is doubtless due to the penetration into the skin of ions trom the electrodes, or irom the solution with which thev are covered, and the skin consequently becoming a better conductor. This property of increased conductivity under the influence of electric agents is similar to the peculiar property of the coherer in the wireless telegraph apparatus, and it is quite within the range of pos>i- bility that the human body may some day be used as part of the receiving instrument in wireless telegraphy as a laboratory curiositv. To accom- plish this, the body would be connected with the two poles of a batterv with an apparatus for registering the slight changes in the electric resistance of the body which would occur under the influence of the Hertzian waves received from the sending station. The Polarizing Effect of Electrolysis Upon the Tissues. After the current has been turned off, a considerable cotmterelectromotive force may be demonstrated by passing the wires from the two electrodes to a galvanometer instead of to the battery. The effect is of the same nature as in a storage-battery. Rapidly alternating currents- of small volume, like those from the ordinary faradic coil, do not produce marked electrolytic effects, and hence do not quickly change the electric resistance of the pan to which the electrodes are applied. Such currents are to be used when accurate measurements of the electric resistance of the body are undertaken, but while alternating currents of the character produced by tin- laradic coil do not produce polarization in the sense of a difference in diemic composition and in electric potential at the two points of the body to which \}\c electrodes are applied, they do produce electrolysis and eventually a change in electric conductivity at these points. Pre- liminary faradization hashing been considered to lower the resistance to the passage of a galvanic current subsequently applied. By the de \Vatteville of combined iralvanic and faradic current we produce an effect upon the tissues which permits the pas^i^e ot a stronger galvanic current than would be comfortable or sate it the latter were applied alone. This may be due to the effect of the faradic current in pre- venting polarization of the tissues. The lissue changes produced by the very rap charges known as high-frequency currents, and th .r-ray and by different luminous rays, are de ters upon t hose subjects. It is probable that in the last analy-is :dmosl all the physiologic effects of electricitv upon the animal tissues should be considered a- due to electrolysis and to electric osn >si- . the last reterrini: to the passage of measurable quantities of a liquid through an animal mem- brane. Some of these different .'flee' now to be described. Effects Upon Nerve-fibers and Muscles. to the bodv causes, according to Hen - . ;i :;irj \n.mi.\i. KI.I:< THI< ITY \\i> HONTUKN KAYS i-fibers iii the direction of the current, i. c., from ; ,. ; . noile inward the cathode. This is coincident with a depressive ipnii the nerve t'uncimns and a wave ot electricity stein, \\hich may be due to a loss of IscleS. Til'' effect Upon the muscles IS to cause ps parah'sis. or in the case ot the unstriped rv tremor, an uncoordinated, con- llut tering contraction of the ventricles, with greater than ,,i\v: n's ol I ides, whicli is the cause of death in man}' | i muscles may be made to contract by the appli- - directlv to the muscle or directly to its motor - '.;: nver the iiei'Ve or over the muscle. A knowledge' .'in im^i'ioii , wliich the motor nerves are nearest the surtace and ' - oi i he muscles (at which the ,'erve enters the muscle; - i:ntio ;i elect r d\ is increased or diminished by electrization affecting t iii . tsnmot or ner\'es ain 1 t he heart . Effect Upon Special Senses. All the different special senses may > eject ricit v. 1 lie patient mav see flashes of light produced ' '. of a current to the temples, and the sense of smell, hearing, and of tact ile and thermal percept ion may be excited. udentlv of actual noise or light or substance with :i-te t hat may be produced by the current . For instance, -'' may be excited bv electrization of the outside of forehead. 'nnt Ihiixilit. The current density has very much -I electrization, and this becomes reduced as the rode, increases. Internal organs, like the brain, i-rnal application only a very widelv diffused cur- -lightl' affected b\ currents of considerable i directly to the substance of the brain v.'ith very much weaker currents. It is Kibrillary t reinor is excited b\" a [lefes from electrodes ap])lied directly t'rent oi twentv milliamperes will hp ed i hroiigh elect ri ides placed on 1 'lie elect rode from a galvanic ' neck and t he oi her nver 1 he ' . are pr< >duced \vlien the oi i he c'|i isii re ot the current is - ' " mi the bra in t o ward t he - most pronounced when the PHYSIOLOGIC KFFKCTS OF KLKCTRK ITY -5UO current is from the eye toward the brain, that is, when the anode is placed upon the eye. An electrode- being applied to each side of the eyeball and a con- tinuous current flowing, a sensation of light and color will be produced. The half of the field of vision cont rolled bv the part of t he ret in a nearest the anode appears greenish, while that perceived by the part of tin; retina near the cathode appears brighter and bluish. Different persons see various forms and colors under the influence of electric currents applied to the eye in these or similar ways. Flashes of light are seen when an electrode is applied to the fore- head and another to the epigastrium. Aii(lit<>rif Ejl'cctx of Elcc.tricitii. -One electrode being applied near the ear and the other to some indifferent point, sensations of sound an; produced by the galvanic current. The effect of the cathodal closure is the strongest, but a sound is also noted at the opening of a stronger current when the anode is applied to the ear. Influence <>f tin 1 Position <>j lh< El-i/' an experiment which he would not advise any one to repeat, but i; 1:01 -s :;nl MKDICAL KI.Ke so great that no very > ; ii .1: current would pass t h roil ill i i he body. In t he author's experiment 'inns were different : the electrodes were constituted by large . . e cio.-rd hand, the large surface and perfect , .;.- | esislaiice to a lllin illllllll. I" inchini: :n bare I Hi-volt direct current conductor with the dry :. _'. t^ive.- i) appreciable sensation under ordinary circumstances. >\\ ever, ' he pi rsoii is .-t aiiding on a floor which is a goi id conductor. i: .. inr e\; ' pie. M shock may be received of the same nature as that - . nil i--'.- experiment, but of much less severity. This is due fact thai ;' is practically impossible to ,'isulate a dynamo from ;',. an ; c 'iisei jiieiit ly a circuit is formed when a complete con- .._: [ii'ovided from either terminal to the earth. A person . loden tioor with perhaps a woolen carpet is pretty I frmi) the earth for currents of this tension. \ ''.- p iwerfu] curi'ent may be aj>]ilied b\" means ot needle elec- - i-l >r-e ti.irether for the destruction of tumors of the breast than -,liar]i [mints of xiuc amalgamated by mei'cui-y. The !- tit :- ly nirned on, and a maximum of _'( n i or .'-inn or more - ' the dil'i'Cl current is allowed to flow even if the anode ':.' .-' into a 'j;rowlh on the face. The heart's action is (>!'.: . is not materially affected. An alternating cur- '.' with sudden variations in streiii:th would - :vs;;lts if iippliei 1 in t his way. ' '' with both terminals of a hiirh-tension circuit at '.: on the surface of the lioil\- may lie followed bv a- contact with one terminal alone, with coti- i; ' ' the ground, or with both terminals at dis- er>al rule that a high-tension current is el'-c 'lose to* quite so strong a stimulant, but is pivi'< rable for a great many cases. The static breeze produces a l<>cal and gem ral tissue stimulation wit hoi; any uncomfortable symptoms. Morton's wave current and the statii induced currents produce similar effect-, but with more sense ni and muscular contraction. All verv high-tension discharges with very MI PI' \l. KLKI TKIdTY AND RONTGEN RAYS derrd to produce effects by means of rather than by transportation of ions ihrouiili the tissues and liberation of chemic products at or near the points of contact. Effect of High-frequency Cur- rents. The different applications grouped under the name of high-fre- quency currents do not produce mus- cular contraction or electrolytic effects corresponding to the quan- tity of electricity passing to the body, and apparently passing through it. This is because the transportation of ions through the semipermeablo membrane formed by the human body cannot keep such rapid rhythm ; - ii currents. The conducting wires transmit the to-aiid-tro currents .. metallic conduction, >imple transmission of electrons without the van -p 1 'nation of inns ( part ides charged negat ively by an extra number r pins, or positively by deprivation of electrons), and subject only o in 1 nrdinarv ohmic resistance and to impedance due to induction. The in its relation to these excessively rapid oscillations may be onsidi-n ; as a capacity which is alternately charged and discharged ;it! 'Ui much current passing through it . It may be compared to a bal- it li a large opening, through which air is blown in and the balloon d and then ;illo\\eii to collapse, an opening at some other point e im: so small that it dues not prevent 1 he balloon from being blown up, during its collapse allows very in tie of the air to escape in that ' . To make the analogy complete, we should have two large ' ippositr sides of the balloon, alternately one and then the ':'.!! closed (hiring I he rush of air into and out of the balloon ' - : iar^e opening. The fact that the high-frequency d >- Hot in greai part ]>ass through the body lias lead to the ' ' .-- found, like static electricity, chiefly on the surface I ; ii- does imt appear tn be the case, ami there is not the < '. '. static electricity, win-re the voltage is much ''>..-.' 'ii oi the charge is much greater-. It 'has been frequency currents have an effect upon deep Pathologic Effects Upon Workers in Electric Power-houses. ises in which the natural power from water - ::! Falls. i> converted into electricitv. and other 'ric furreni is transformed from the very i] 'Jn.nno volts or more to the utilization abnormal coi id it i< ins for t heir work- .1 percept ible effect U])oll any rroun " tese \- induction coils, etc., and it is fortunate that the influence from those ot a suitable capacity for .r-rav and electrotherapy seems to be beneficial rather than harmful. However, lotm exposure to the ./'-ray itselt is very harmful, as is stated more fully elsewhere in this book. The effect of high-frequency currents upon the tissues is very important, and is found in a separate chapter upon that subject. Effects of Condenser Discharges. The most valuable observa- tions are t host 1 which determine t he single discharge necessary to produce a muscular contraction, and then the frequency with which thai discharge 1 American Medicine, A iiru>t, I'.'Of,. p. ~2 '>.'>. Ml. Pit \1. Kl.Ki IKlt in \\1> HI >.\T(,K.N KAYS i usi l)r iv] >t -a it-.! in order to produce tetanus. These vary in different ; : iiscli - ml ii: i ; : i'l e n -n I an imals. A Miiiabie arrangement of apparatus is shown in Fig. 217. ' The 1 1 : .[ - I . ainl I arc apph'i-d in i lie annual experimented upon. One i-ti i v. ; : mie an at u iv oi a condenser M. having a capacity of microfarad. I'lie other electrode is connected with a pivotal point, i '. n:' a tine pi: ire, which carries a small iron hammer at one side > >sin<: >pring al t he ot her side of the pivot. \\ hen t he ha miner 'd lr. tiii action of an electromagnet, the point X makes an in i. ! cup of mercury, and through that with a source t '. iif \ [oteii! ial. I'he animal and t he condenser are t hen charged ; i tiii '[ potential, and the quantity of electricity may be calcii- ';<.; :: >:i I 'he voltage and the tixed capacity of the condenser. The < -'v df the animal is tixed also, and is only a small fraction of the >! the condenser. It dues not affect the calculation. \Vhen ii :.-: ii ' ceases to act, t he spring breaks the contact at X and 1 ." merciirv cup at L, and t hence to tin discharged through the animal heiween i-niial consists of a battery 1'", the two the extremities of a resistance wire, : : . There is a .-liding cont act , ( '. 1 1 : to the animal and the I he contact is at A, to 1 he full -pa rale battery P. the 1 i. which 1 1 ips into a mercury ' e mercury when at rest . '. . i he durat i"" of each is flowing. :' adj ; - ; :: ; ile length, and ;i,d'T 1 e influence of its own I'll VSIol. ()(,!( I.I- FKCT.S OF KLK< TKK Ti V 300 r; ( ', t iliiYrrcnt ground connections: X. battery, P, and its ovni electromagnet. There is a separate electric signal which may be brought into this circuit bv turning the ,-,witch 1 rom m to p. instead < >l fr< mi m to n. The signal acts synchron- ously wit h t he mot ions of t he vi- brating interrupter and enables one to count the latter. A simpler arrangement is used 'e when single or isolated condensi r discharges are applied in elect ro- diagnosis or electrotherapy. ( >ne armature of t he condenser ( ' ( Fig. _'l s is grounded ; t he ot her arm- ature is connected with the pivotal point of a Morse telegraphic key. In the normal position a spring causes the Morse key to make contact with a wire leading to one pole of a battery, the other pole of which is grounded, and in this position t he condenser quickly become- charged to its full capacity at the potential of the battery. Depressing the Morse key breaks the connection with the battery and makes a connection with a wire lead- ing to the nerve or muscle, from which another wire leads to the ground. The condenser discharges through the animal and the ground, as they form a complete circuit between its two armatures. A metro- nome dipping a wire into a cup of mercury may be substituted for the Morse key when discharges are to be applied at regular intervals. Condensers for diagnosis or treatment have a capacity vaiying from -i, 1 , ,, to 2 microfarads. The condensers used in the arrangement described above are of large 1 capacity, having 1000 or several thousand square 1 ine-he's of con- den-ing surface, and are charged to a potential of '}() to 100 or '200 volts. Effects of Leyden-jar Discharges, Condenser Discharges ho armatures of the jars are connected " t machine ( Fig. 'JlO . The oute that of tlu 1 other jar is connected \\':' i 1 electi'odr a]i])lii the patient. The])atient is i The (lischarging ro ( static machine are close together. T: 'wo inner armatures di>c! ; ix r e :;in Mi:i>i' M. KLK;id< n-er i li-cha: tie- arc severe. 1 , ;;, ,'ts 'f condenser din-barges of different quantity, potential, naturallv variable. The factor of quantity is found lr. ini: the capacity of the condenser by the voltage to i j: is c! ai'ircd, '. ire contraction. A condenser of a fixed capacity is used, and ide- applied to the exposed nerve are connected, as shown in l-'itr. _'lv The cntidenser i.- at first charged and discharged at a very '. ;::. which i- gradually increased until a minimal muscular '. in i- produced. The capacitv of the condenser and the vo. ,_;, are recorded, and then the same experiment is tried \\ith a , tf civil! known capacity, either greater or le.-s than l he first. |i is found that the voltage to which diffei'ent c ''. ;'!-*:- n.M-i be charged m oi'dcr to produce equal mu.-cular con- *ion- does not varv inversely as their capacity, as would be the ' ' .e -ai ic quantity of electricity were discharged in each case. !" coiidhion- required correspond more nearly to those in which the : u r i- the same, so that in each case \('\"- amounts to the '.<-. The required voltage, therefore, varies approxi- ' ie square root of the capacity. If a condenser , : ;-' be charged to a potential of 'JO volts in order in. the -nine effect would be produced tour times that capacitv. charged to a potential of ; > condenser ot one-fourth that capacitv, charged These proportions hold good within b ;i : nl ' u extreme ca-cs. Thus, a single discharge ible conilen-er fail- to u;ivo muscular contractions only one volt. I-!ven in this case. ' condense!' discharges will produce doe- not appear to be due to a lessened 1 ' . '. does not re-nlt ;'n mi successive : Uce hardly ailV elect 1'olyt ic at ion being due to an overlap- f ion , \\-it h a ci mse(|uent cumula- I I e fact t hat the height of 1 . i he ga Ivan ic cu rrent is con- ' : inul i are a p| >\ led in rapid 1 '' ; ' ' e bo . however, be modified MI rent fi i' -i une t ime. and t hen . i i pn iduce a great er efTect PHYSIOLOGIC KFFKCTS OF KF^KCTUICITV .'ill The physiologic effect of a single condenser discharge is clearlv modified by the useful duration of the discharge, but there is a question as to this brin; called the law of stimulation by condenser discharges, us surest ed by Clu/et. 1 and the Lapicques have made a series of experiments to determine this point and with negative results. - The duration of the discharge, of a condenser is, however, considered by Lewis Jonrs :i as affording the best numerical expression for the con- tractility of a muscle to this form of stimulation. (See also page />()(). riuzet, Dubois, Zanietowski, Iloorweg, Cybulski, Weiss, and I'revost and Hat tell i have- made accurate experiments wit h cundenser disci utrges. This must be regarded as a new and valuable addition to the means of elect rodiagnosis and electrotherapy. The effect of a condenser discharge may be modified by introducing an additional resistance or inductance or capacity in the circuit, the effect being to reduce not so much the intensitv, as the, duration of the discharge. The length of the wave of stimulation makes the same difference with condenser discharges as it does with the make and break of a continuous current. Muscular Contraction from Rapidly Repeated Condenser Discharges. -Applying two metallic electrodes to the sciatic nerve of a frog, tetanus is produced by discharges of the same condenser. charged to different voltages and at a different rate of speed. Frequency per second. \'<>ltn(> a second produce the most powerful contraction. Such condenser discharges produce effects which are very similar to those of the faradic current, but they can be much more accurately measured and applied. 1 he same thing is true ot single condenser discharges as compared with isolated induction shocks. Muscular Contractions from Condensers in Parallel with Galvanic Currents. The length of time it takes to charge or discharge a condenser at voltages ordinarily u:;. 3 Archives of the Roentgen Hay, Ma 1 \nicr .lour Kle('trotherap<'Utie- aiu p. 207. :',!_' Mi-iDit AI. n.i:' TI;H rn AND KONTGEN HAYS mii-ci;'.;. ; '( 'in raci ion. There r- a similar ettect at the break. The . _ , irn 11! -' hould he by means of a liquid or a the ordinary wire coil rheostat. Tlu v [c ii'ivi-s an induced current with its well- ici al ini] ii muscular << mi ract i< ns. 1 . Hen.a u-e- the condenser discharge ajiparatus of 1 -he- and vulcanite discs wit h copper sectors. ivi- 1 [eii-er discharges a second. 1 behm tienerally 11 . KK). 1'Ui may he changed to 200. 'Die . n d at loll volts should he noted. If there is ii _' .10 covery may -till take place. But if response a r- after 1 2 discharges i 1 per second) the ease n c< iver wil IK >ut operat ion. ve lieen oh-erved hv Hollet to produce the 1 e hi. mil as ot he! 1 form- of elect rich y. Tie has found LIVS may clarify the hlood. The hlood would 1 nf a traii-parent red li()uid in which float colorless and o-e h'-nioulohin has hcen di>>olved out by the blood Ti > In fiiund takes place even when the lieatiiiti' effect of the - eliminated. I'nder other cireumstaneos, as where ."I i- -ubjertcd to a coiiden-er discharge, the amount ' _ .. : ted i- aiiijily -uflicient to account for the clarifying of Max ( '. UK ! colliders the thei'inal (-lenient as the chief one on, it' it affected any considerable portion of the the circulation, would be of vital importance. The property _i'ii ni loose combination from the hum's to the iiues, , from the tis.-ues to the lun,u-. is practically lo>t by . : : ' i- di. -lived out of the red blood-cells. It will - the principal reason why salt M>lr,tin is ' " ' .' vi in.- afti'i 1 hemorrha.ue instead of plain water. the hemoglobin and defeat the very object nt - ' ' oxygen-carrying ]ower of the blood. . . oWeVe) 1 . It IS ll'it to be supposed that ducetl iijtoij the blood in the li\'ing body to . '.>.;. ! " affect any \'it al funct ii m. DuBois-Reymond's Four Laws of Electric Stimulation. 1. The > 'tie -'reiiii'tii MI the current or ampej'age which i". nerve, ir oi her 01 ^an. ches I he oi'^an to be St illlU- . i-U I'reiil and part ly upi in 1 he II direct ions irreat ly reduce.- lie of I lie elect I'odeS is e lat tel 1 is quite near if the 1 1 iff erei it muscles PHYSIOLOfilC KFKKCTS OF KLKCTHK'ITY ?>}'.>> '['he. ])<>lar effect is evidenced by the swelling from muscular contraction which takes place in a striated muscle at the cathode when. the current begins, and at the anode when the current is turned off. The polar effect upon unstriuted muscle is evidenced bv a relaxation of their normal tonic contraction at the anode during 'he passage of the current, and at the cathode when the current is turned off. The polar effect upon a nerve is a \vave of stimulation starting from the cathode when the current is turned on or its strength is increased, and starting from the anode whenever the current is turned off or its st rengt h is diminished. 4. The cathodal closure effect is >trontrer than the anodal closure effect. DuBois-Reymond's Law of Electric Stimulation by Variable Currents. Kxpres'sed in differential calculus, e = const, the d i effect is equal to a certain constant multiplied by a differential of the current divided by a differential of the time. This law must be modified for application to different forms of current. The opening induced current from a faradic coil is not opposed by self-induction, and is more effective than the closing induced current. True sinusoidal induced or alternating currents which are svnnnetnc in both directions are difficult to obtain, and so condenser discharges have been used in testing the validitv of the law. Cybulski and Zanie- towski, Hoorweg, G. Weiss, and Lapicque have obtained widely different rest tits. C\' is the quantity of electricity contained in a condenser of a certain capacity, designated as (', which is charged to a potential designated as V, and %CV- is the energy required to charge it and liberated by its discharge. Prevost and Battelli have found that the condenser discharge necessary to produce a fatal effect is determined by the energy of the discharge, or \('V' 2 . Hoorweg 1 has found as the result of many experiments that the voltage to which a condenser of a given capacity must be charged in order to produce a minimal muscular contraction by its discharge may be expressed by the formula MUSCULAR CONTRACTION RESULTING FROM ELECTRIC STIMULATION ill 1 MI.DK \I. KI.KI I'iJKIl'V AM) KOXTCEN HAYS in it' lin orain or -pinal cord, or reflexly by the stimula- : - ' r ot her nerve. \: r nf ihi.- effect nf the electric current is seen whenever : (! - . in the two hands. ;iiul the muscles of' the hands and i until ence ol ;i faradic current . >: i he nature ol this effect is based very lar^elv upon e\p< i nil ' IMTVCS and muscles of recently killed animals. ' i :;-'< i\i TV u: tlii- physiologic effect of electricity was ,\ ho I'liuiul 'hat when a pair of frog's leu's were I nes would ti'Uch a metallic surface, the muscles of h contracted and the toes were drawn away fnuu The mu-cles re!;i\ed au'ain. allowing the toes to face, ;.nd contraction aiiain ensued. This went on jierind of t ime. l)i it t he coin ract ions gradually became \ ceased. : ' its natural saline moisture, t he object from which -.-: < i- < 1 . a nd t he mei ;il I ic surface touchi d b\" t he toes formed , v. current passed through the limb and made the ci'ii't'act. The toes beini: drawn away from the metal, the nd t he muscles relaxed. A Complete Neuromuscular Preparation. -This may consist 1 1 epared HI -uHi a wav as to enable one to make accurate '-.;. electric stiiuuli. The frog's body is cut across at the i : ' Idle i if the abdomen; the skin i.- stripped from the les p; i nf t he bndv. The lower part of the spinal column is -. : ' i-il b -.:_;' dissect ion, and so is t lie en t ire leniM h of In it h sciat ic -. T ipp p; ri of the preparation is fastened to a stationary : '1 the table-, while the foot. or. in some cases, the separate tendon o] the liast rocnemius mii-de. is fastened to some movable object like a .'.'. c _!i" or lever. The latter may be connected with a myograph or it i- to reiii-Ter the contraction or elongation of the muscle. A Simple Neuromuscular Preparation. This is a muscle with its n ached to t he muscle, but the whole preparation . ' .:. - .:. a u ay a- to be used for observation on t he muscular . In stimulation nf the motor nerve. These : not Iv completely removed from the body. If tal is alive in some cases, and then the thi ' iid muscle may be left undisturbed .'.: "i i; e [n-oper blood-vessels. In any case : ' . u iiile verv < >ft en the tendon ' i : : i I i i . Ma:nt Cirrulation in a Neuromuscular Preparation. ' : ' !>' ci ill! i nil e<] b\" lea\'ilm' its blnnd- I : e latter results chl'eflv 111 all il ! ei' elect ric stimuli and a less reai 1\' Fhe Use of C::r;tre. \ motion of a living muscle under n- Use i if cura re, \\ hich - 1 >t i,i ! ni or nerve in t he muscle it self lat t or c;i n hi done < ju it e ' ' ' ' ' ':"' li 1 :il canal behind i he head. PHYSIOLOGIC F.FFKCTS OF ELECTRICITY 3ir, THE MYOGRAPH The Myograph. In its simple form (Fi.tr. 220) the mvogniph consists of a lever to which the free end of the muscle is attached and a Flu. 220. --Simple tnyo^nipli in nprrat inn. revolving cylinder upon whose surface 1 the movable point of the stylet traces a line. Isotonic Contraction. Isotonic contraction is shortening of a mus- clo au'ainst a uniform resistance. The re-istance in Fiir. 221 is l\.<- w( > iji'ht of the lever, and is practically the , A , -iidit of tin- lever. It is upon this principle that :',-n i]-( 1- ;i iv u-uall \' made. Isometric Contraction. This has reference to the traction force .',.. i 1.,,'h ends of which are fastened to stationary or objects, so that the muscle cannot shorten to .lent. A mvi 'ti'i'aph in which t he muscle is connected .,: (:.' II-YIT Yel'Y near the fulcrum \\'ill register isometric u!>\\ard motion of the leYer is opposed by a spring i- properly graduated (Fig. 222"). This method has !> - : i.-ei] to any extent . \. ,f :atices on an isotonic myographic tracing show that the d in certain extents, the shortening being opposed ' , weight. (Mi an isometric tracing vertical distances certain -nvngths of traction (e<|iial to sustaining certain ,,n the part of a muscle which is not permitted to shorten \1 rolled on another one w the registering point rests upon the moving strip of paper (Fig. 22v>). The cylinders revolve by clock- work actuated by a spring or a weight, and the speed of their motion may be regulated according to the rapidity of the changes it is desired to register. Marey's Drums. A pair of t hese const itute a means of transmsssion of the motion of the lever to it a distance by mean- of pneumatic pressure. 'These are en it i- convenient to have the neurornuscular prepara- 1 fm -d experimented upon in close proximity to the regis- i- i- frequent 1\- not t he case. The part experimented e or the arrangements for the experiment may be Mir.fm, it i- often desired to register several difi'erent -t rip of p;i per. ;i MI 1 it may be impossible to group near I he n-volvmu cylinder. The additional quired are t ho-e reui-tei-mg the units of time and !i -ct rie I'urrent . ( )t h-r t raeinu's somet imes made a ri-nm' in t he tK-i've and muscle in con-e(juenc(' . _'_' ! 22i i i- a flat . round liox of sheet metal s(\-d( 1 d : >< r over the top and with an opening at the ' lorm- a coMiiect ion for a ruliber tube leading :n:i', 1 > -e\'er;d feet away, 'hie circular side, hi ad of t he drum, i- < if << >t'i nil >\ ier so t hin 'i! ion 1 hi- t hat t he force of 1 he lever is PIIYSKiLdCIC KM KITS CI" KLK< "I KI( Tl'Y A B Fig. 224. Maroy's drums: .-1, transmitter; B, r brought to bear when the muscle contracts. This compresses the air in the drum, and the compression is communicated to the air in the other drum, causing motion of its head and of the registering lever connected with it. The transmission is effected practically instan- taneously, being at an average rate of 2SO meters a second. Several of t he receivers may be grouped near the registering cvlinder, , , and each one trace a separate line upon the chart, recording the impulses applied to the transmission drums connected with different elements of the experiment. The latter may be set u]) in separate parts of the room if desirable. Marey's drum may be used to study contraction in uninjured human muscles. The drum is held against the lateral surface of the limb bv a Ml. DK AI. KI.K< TKICITY AM) HOXTGEN KAYS itter-like -trip i if -heet metal which i- bandaged over it. When the in tract- ami -well-, the latter motion i- t ransniil ted through Maivy drum- to tin- reLii-t erinir apparatus. Time Registration in Myographic Charts. This may IK- done in , -in i nli -i ra-e- liy not inir the time of starting and stopping the revolv- _'_'?. .1, Pciululuiii interrupter; 5, metronome interrupter. Ilori/ontal di-tances on the chart indicate periods of n he approximately calculated. makinu a tnteinc are suitable for cases in which the time units to be recorded are seconds or a large fraction of a second. As the pendulum swings to and fro under the influence 1 of clock-work, which is not shown in the diagram (Fig.' 227, A), the contact is made and broken. Kach time that the bat- tery circuit through the electromagnet is completed its armature is attracted and it is this motion which is traced upon the chart. The rapidity of the to-and-fro motion of the metronome (Fig. 227, B, and 22S> may be regulated so that the signals occur at intervals of from one- tenth to one second. Those of the pendulum are subject to about the same regulation. This is accomplished in each case by changing the distance of the movable weight from the axis. The Tuning-fork or Diapason a.s a Time Index with the Myograph. The handle of the tuning-fork (Fig. 229) is securely fixed, while the prongs are free to vibrate. When at rest . one of the prongs is in contact with the wire, w, and completes an electric circuit through the batter}-, the electric signal and another electromagnet, which is placed between the prongs of the tuning-fork. This electromagnet attracts the prongs of the tuning-fork and breaks the contact. The magnetism disappearing with the cessation of the current, the prongs of the tuning-fork airain diverge, and the contact is reestablished. This is repeated with a rapidity which depends upon the natural rate of vibration of the tuning-fork, and this varies with different tuning-forks : and tin- same tuning-fork may be made to vibrate faster or slower by fastening a heavier or a lighter weight at a greater or less distance from the end of the prongs. The vibration rale employed is from one-tenth to one-two-hundredth second, most often one-one-hundredth second. Dexprez'x Electric Signal (Fig. 2211 ' This is a little apparatus which may be placed close to the moving sheet of paper in the myograph, and traces the units of time upon it. There is a tiny electromagnet which acts upon an armature. The latter is of very light weight, and is pivoted upon an axis which is provided with a stilet which traces a line upon the moving sheet of paper. The electromagnet and armature are both made of verv pure soft iron, to prevent any permanent mag- netism, but even then the armature may not be instantly relea>ed on account of a trace, of permanent magnetism. A sheet of paper interposed between the magnet and the armature will prevent this. A delicate spring draws the armature away when the. current is not flowing through the electromagnet. The range of motion is very slight the point of the stilet moves only about 1 mm., or .2.1 inch, just enough to make a perfectly distinct break in the horizontal line traced by the stilet when at rest. The electric signal i- so that it will register even - ', ,/ second, wh is ever necessary. Figure 2:i() is a part of the time tracing from a chart made by the author. The breaks in the horizontal li i< the actual si/e of the tracing upon I hi much more rapid rate would have to be moving at a much more rapid rate that moves onlv \ inch a second. TKI< ITY AM) KONTOKX RAYS Electrometric Charts.- Klectric currents arising in the tissues .-y. of in consequence of artificial stimulation of some kind, i [viii>teivil upon a mvouraphic cliart. together with the other of i lie cxpffinieiii . Thi> i- I test done by having the moving of paper -en-iti/rd to light and inclosed in a camera, and casting mage of the capillary electrometer upon it. Variations in the if the column of mercury are registered upon the chart. The if the elect ronn't ric method are given on p. ^22. Myographic Charts. Where several differ- ent factors are to be re- corded, the most satis- factory way is to make the tracing upon a long strip of paper. Hut where the character of t he muscular << >nt raction alone is to be recorded and a comparison is de- sired between successive contractions, it is often desirable that the paper should be a short strip wrapped once around the revolving cylinder. A simple mechanism cylinder >lightly after the completion of each revolution, , : .at rest t races a series of pa ralli ! liorixont al lines. p cch: iii-ni makes an electric contact at each revolution .''. each time at a slightly later period. A convenient i-fumpli-diinu: this i- shown in Fig. 2. 52. A cog-wheel '. i- ::-< ii' -d to the a: \is of the cylinder and causes the n >i at ion of allot her wheel wit h I'M teet h. A project ion at a cer- t a in | ia rt of the circumference of ' i- hit ter produces an elect ric con- tact evi TV t inn 1 t his wheel makes a complete revolution, and this ; '.'- a lit 1 le longer t hail t he \\'heel PHYSIOLOGIC EFFECTS OF ELECTRICITY 321 with a smaller number of teeth. The tracing in this rase show- each muscular contraction separate and distinct, although the lines may cross each other as in Fig. 233. EjJ'ect of Speed of Mot/on of the Paper I'pon the M ijoi/rop/i/'c Curve - If the paper moves very slowly, each muscular contraction may be registered as a simple vertical line. The motion of the level' bring rapid the up-and-down stroke may be complete before the paper has moved an appreciable distance. The tracing of a series of contractions under these circumstances looks like the teeth of a comb (Fig. 234 j. Such a tracing is valuable when only the height of several successive contractions is to be recorded, for instance, in studying the effect of fatigue upon_ muscular or nervous excitability. Fig. 23") is such a tracing showing fatigue from successive stimuli applied at interval- of two or three seconds, and registered upon a slowly revolving cylinder. The 1 , paper has moved only the distance between two successive lines during two or three seconds. It enables one to compare the height of a large number of contractions at a glance, but gives no idea at all as to the relative abruptness and other important features of the upward and downward strokes of the stilet, Fig. 234. Comb-like tracing upon :i slowly moving myograph. Fig. 235. Stair-rasp phenomenon from fatigue uith periodic .stimuli at interval- of two or three seconds and with .slow rotation of cylinder (Weiss). The cylinder revolves much more rapidly for this purpose, and tin- vertical motion of the stilet makes an oblique mark upon the paper. This line will usually be found to be curved, as in Fig. 230. If the paper moves at the same rate in a series of observations the abruptness of the upward and downward portions of Fig. 230. -Tracing upon a rapidly revolvini: myo- the curve will vary with the graphl abruptness of the muscular contraction and relaxation, and the entire length of the curve will vary with the time elapsing between the beginning and the end of the con- traction. These features and the latent period or the length of time that elapses between the application of the stimulus and the beginning of the muscular contraction are among the chief indications furnished by the myograph. Registering the Latent Period of Contraction. Three different elements must be recorded: the unit< ot tune, generally indicated by a tuning-fork and Desprex signal: the rlo-inii' of the electric circuit, also indicated by a Desprex -iii'tial: and the muscular contraction. In Fitr. 237 the myo^raphic tracing is represented as being made by the muscle (Mi directly, though very often it i- made through the inter- mediary of a pair of Marey'- drum-. The mu-cle is stimulated by a faradic current, and the primary current ot the coil pa-ses through a De-prex signal (S.S.I, which records the turning on of the current There is an entirely separate battery 1>.2. to actuate the tuning-fork 21 !V22 MKDICAI. KI.KCTHIflTY AM) HOXTCrEN HAYS and the IV-pre/ -'mnal iT.S.,1, which records the units of tinu hun- dredth- of a -econd ii-ually. This arrangement shows the length of time tint elap-es between the application of the stimulus and the . res[>onse o! t lie muscle. A similar arrangement is em- ploved for (letermininu the latent period when the stimulus is ap- plied to t he nerve m-tead ot the muscle. Registering Muscular and Other Bio-electric Currents. A pair of impolarizable electrodes (I''.. E. Fi<:. 2oSi are applied to the part to be tested, and are connected with the capillary elec- trometer ( '. An arc liu'lit of 500 candle-power and a suitable sys- tem of lenses and camera casts an ima.u'e of the column of mercury through the slit. X. and makes a I !- -'.'57. Mi-ii-urt-incnt of tin- latent ])!lot o.U'raphic record 11 pi 'II t he seil- ntr:t. : tinii. Myograph arrant;...! ^\- /( . ( \ paiMT as the registering nl init- oj tiiiii-. the appliratiiiimf tin- ... , ... , ira.ii.-.-irrcnt. ati.l muscular contrartidii. cylinder revolve-. All till' other elements IliaV be recoixled \lpoll he paper at the same, t ime by suit able electric signals and Marey's p ii' d includes a dark room. >mnlar to the room I'n ' ' '-I ' ' ' - '' ' ' i I!.;.'', piioto- ln formed I" 1 placing a partnion o| compo-boanl ' ' . : ! ; ' ' <: ' . I hi hi i- me|i i-ed in a 'led roinel er 1- placed b' ' Weeli t his and a 'I'hc l;it ler pa-~i |>f"of opfliilifr and for:i i he leu- of a reirulai 1 phoii .;: i-;i phic . '.'''. Id' bai'l >l ' i- cami 'i'a is < made wide or na rn >w. The : 111 fall- up- 'ii the sensit i/.ed I. I'.-H -... \ ii, I !()o [' .V'7 PHYSIOLOGIC EFFECTS OF ELECTRICITY 323 paper. The cylinder makes a complete revolution in from two to eighty seconds. The time units are registered either by a metronome, each ascent and descent indicating 0.37") second; by a tuning-fork indicating r ^ second; by an electromagnet making twenty vibrations a second, or by a Jacquet chronograph indicating one-fifth second. In making such an observation a frog is narcotized or the brain is destroyed; it is carefully insulated by rubber tissue, and fastened upon Marey's myograph, and individual muscles are removed with the nerves still attached. The impolarizable electrodes from the capillary electrom- eter are applied, and if there is a current of rest, sometimes amounting to i 1 ,,- volt, this is counteracted by a battery and shunt circuit. Then the nerve is stimulated, and the muscular currents, or those that arise in the muscle in consequence of its contraction, are recorded photographically. Burdon Sanderson 1 has done much valuable work upon the detection of electric currents due to the stimulation of muscles. THE ELECTROCARDIOGRAPH The Electrocardiograph. When any muscle contracts, the active part becomes negative to other parts. Waller, in 1887, first demonstrated with a capillary electrometer currents due to cardiac activity and derived from electrodes applied to different parts of the surface of the body. Electrodes in the form of bands of metallic gauze 1 covered with woolen cloth may be wrapped around each hand, or a hand and a foot, or each foot, and when connected with a string electrometer will show electric currents which are synchronous with the aciion of the heart. The curve registered undergoes characteristic variations in different cardiac lesions, and this has become an important diagnostic aid in the hands of the heart specialist. The various positions of the electrodes give different normal curves. Kinthoven's string electrometer 'page 175; depends upon the deflec- tion caused by the passage of the-e weak and transitory currents through a quart/ filament tightly stretched in a powerful magnetic field. Minimal of Phv-iolnuv. ls<).">. vol. xviii. p. 12s. MKDK AI. KI.Ki THK ITY AND KoXTOKN KAYS Nicolai and Huth's portable electrocardiograph i Fig. 2l-> ( .)) is a de- derided impn i\ vineiit . 'I'l it st H i ig elect r< >met < T (page 17")) consists of a phii i in 11 1 1 ti la 1 1 n -in I inches long, with a n '.Distance of (iOOO ohms, stretched in tlir held of an elect romagnet which weighs GO ])ounds, and must be actuated 1>\ a direct current cit her from t lie electric-light circuit or from a -torauc battery. ( M her parts of the apparatus arc au incandescent i . ctric-liu'ht vacuum bulb. 1 cubic meter.- in diameter, in which 1 here is a band of Wolfram or lungMen. 10 millimeters long and l.o millimeters wide, and through which pa.-ses a current of 7 amperes and 110 volts. The iv-ult iim imlii i- as powerful as an arc lamp and has the advantage of ret juirini:' in > a< Iju-t ment . The entire lenii'th of the string is not shown, only a portion at the middle, which i- >een through a slit at a rijrht anjile with the length of the -trinir. The imauc is projected by a Zeiss apochromatic 1() millimeter object ive and No. 12 projection eye-piece, and a camera bellows excludes daylight. The registering apparatus is all enclosed, and contains a roll i if 1 in imide paper <>0 meters long and (5 centimeters (2?, inches) wide, with an elect ric motor which draws a certain length of the photographic paper pa-t the >lit and registers tenths of a second upon it and numbers the strip. A Maivy'- drum at the same time records the pulse 1 or any other function de-ired. At the same time the record is being made the image Hypertrophy of left ventricle. lrn mil h:iiii| in ilii- oilier (after Boruttau). !i a irnnmd ula-~ -creen, 1'i-e-siug a cerlain le\'er 1 " i . cut- c iff t he portion already exposed, and de\-e|f)piuii ciiamber. f roll i which it emerges a lini-hei | pi ct lire. il loui lL'"i pound- altogether, but i- made up may be ea.-ily handled. It can all be placed |c and ."(! inche- |< .nu. pparatu- -hoiilil be adju-ted so thai 1 centi- PHYSIOLOGIC EFFECTS OF ELECTRICITY -M-) the resistance 1 of the patient is to he measured and is usually hot ween 200 and ">()() ohms. The most desirahle leads or derivations are: Lead I. Right Arm to Left Arm. Lead II. Kiu'hl Arm to Left Leg. Load III. Loft Arm to Left Log. I'lntsc* of the Electrocardiogram. Fig. 241 , / J , coincides with t he auric- ular systole: (j, R, N, and T with stages of the ventricular systole, 1\ and T being the most important in diagnosis and always present in health. 'Flu 1 spaoo between '/-* and Q is the auriculoventricular interval, and shows the time required for the propagation of the impulse through the Q 5 Fisr. -11. I'ha-cs of the electrocardiogram. bundle of His. Q shows the ventricular contraction beginninu; at the hase, and I\ the wave of contraction reaching the apex of the heart. The ventricular curve gives an index to the functioning of the limits of the auriculoventricular hundle. described by the .Japanese physi- ologist, Tawara. Electrocardiograms are not directly affected by movo- ments of the blood or t he condit ion of the valves. They "ptnvl v express changes in the electric condition of the hearl due to muscular activity." 1 By -ome aut hors. T is designated as V . S as .). Interpretation of Electrocardiograms. ////////////,/ / tin Ventricle. R. I (i.e., I! with Ic.-id \o. I i> a very -mall iijiward projec- 1 Walter H. .lame.- and Hurntiu I'.. William^, Aiut-r. .Itnir. Mnl. Sc-i., Nov., I'.Uo. .>'Jt> MKDIt AL EI.Kl THK ITV AM) UONTGKX HAYS t ion or may even l>e downward. //. Ill is upward and of greater magni- tude th;tn normally. /////" rtn>i>hn <>f tin Lift \'fntriclt.- /.'. 1 i.- upward and of fi'reat hi-iirht and II. Ill i- di > \vn\\ a I'd to t he extent of perhaps - millivolts. H >//n rtro/ilt'i of tin iiiiriclf* may increase the height of I'. A negative aftrr-variat ion or T is always almormal and is often found in '/'/..- i'.-, // /-M.V/.V. in which di-ea>e it is an unfavorable sign. I- -V LEAD ' -inu-oidal liath-. and in one ca-e. irpi.rtcd (,\- 1 . and all I lii- ca-e- were 1 icnefif ed. \ di ' i tii in N nf 1 1. 1 in 1 .'_!."> m i Hi vi >lt i- el i;iract eristic "' '"'' irn.^ln niii. It i- nf ]i- fre ( |i]rni i ,c,-iirrence " i <-nr!,. \ . PHYSIOLOGIC EFFECTS OF ELECTRICITY 327 An insufficient positive after-variation T in many organic cardiac or arterial diseawx is improved by sinusoidal baths (Strubel). Rapid puke shortens the diastole represented by the distance be- tween T and the following P, and is extreme when P and T coincide. Irregularities of cardiac rfujtfint are clearly shown, also extrasystoles and pulsus bigeminus. \'entricular extrasystoles sometimes give a high T wave followed by an N wave extending far below xero. Com- pletely irregular heart, nodal rhythm, or pulsus irregularis perpetua show several small diastolic waves in each cycle without any normal P wave. This is thought to indicate that the trouble is due to auricular fibrillation (James and Williams). In arterial hypertension and renal sclerosis the ventricular contrac- tion is slow and jerky, and also in mitral stenosis. Functional trouble of the auricles and aortic insufficiency are clearly shown.' Experimental section of one limb of Tawara 2 produces an enormous increase in ventricular, E. M. F., and an approach to a diphasic curve with a gallop rhythm. James and Williams give the electrocardiogram of a patient, with possible lesion of the right limb of Tawara. The patient has moderate hypertrophy, dyspnea increasing for the last five years, second aortic sound accentuated, no murmurs, but gallop rhythm. H. Yaquez's investigations show no information as to the energy of the cardiac contractions/' Experiments by U. H. Kahn 1 and by Eppinger and Rothberger" 1 show that the currents produced by the two ventricles are in opposite directions; and Rothenberger and Winterberg show that these currents are not synchronous, and that the different phases shown in an electro- cardiogram correspond to the contractions of the different portions of the heart. 1 '' The heart-sounds and the electrocardiogram have been registered together by R.H. Kahn, 7 who finds that the first sound falls between A* and T: the second sound begins -^ second after the end of T. Pachon's left lateral decubitus is desirable for electrocardiograms. A. Lohmann and AI. Rinek give practical directions for the use of the string galvanometer and photographic registration of the same. s Dr. Walter B. James and Dr. Horatio H. Williams in this country have 1 made important contributions to its clinical use. Duhamel has invented an electrocardiograph provided with a dial and needle." Currents of Action in a Muscle During Tonic Contraction. The current has about the strength of , n V,, Paniell cell, and the wave of nega- tive variation has a speed of between 1 and 7 millimeters per second. 1 " Currents of Action in the Ureter.- Triple phase currents have 1 been demonstrated, corresponding to the peristaltic waves in the ureter. 11 1 H. Moulinior, C. R. S,x>. do Biol., Ixxi. 1M4. .July I. 1911. " Kppinuor and Kothbor^or. Zoithsoh. f. klin. Mod., Ixx. 3 C. K. do la Socioto do Biol.. Ixxi. 12 X. .July 1, 1911. 4 ( Vntralblatt fiir I'liysioloajo. xxiv. 7l2X. < )otohor 129, 1910. Ibid., 10.")-:;, I'Ybnmry 4, 1911. fi Ibid.. 9.-)9, .January 7. 1911. 7 . \rohiv. fur dio ^os. IMiysiolotrio. oxxxvii, .">97. 1010. 8 Archives fiir Physiologic, 1. 417, 1910. 9 C. K. do la Soo.'do Biol.. lx\. 10(1, January :21. 1911. 10 Th. v. Briioko. Archiv. fiir die gesmn. Physiol.. 1910. oxxxiii, 11 L. Orboli and 'I'h. v. Briioko. Aroliiv. fiir dio ^osain. Thy: p. 344. >-> MKDICAL KLK< TKKITY AND HONTGEN RAYS Currents Produced by Cold Applied to a Nerve. The portion of a nerve which i- cooled l>econie- positive to any other part. 1 Contraction of the Separate Muscular Fibers. -This is a process of traii-ver-e thickening and of longitudinal shortening, and is probably connected with ;: diemic change in the protoplasm which is rapidly re- _;'; alter i hi contract inn ha.- ceased. Contraction of a Striated Muscle. Thi- occurs under the influence ; ric -; i I us. u>ua 11 v as a shortening and swelling of the entire nj: :it tin- cathode extrein- ave of swell in g advancing along lling at one end of the muscle. Th xperimentally at the beginning t on may be pr .:. t hn>uu'h t he rectus abdnminis muscle of a frog, ed out and pinned to two cork-. Impolarizable electroiles hi n-ed. This muscle present- transverse tendinous septa, and . '._ ; the passage of a ci >n-t ant current, from one end of the ' ' ' >t hei a -welling is seen at the cathode end of each niusfu- ti<>ti l - 'iir. -H . A -weiliim i- pro(luc(>d at the end where the mu-cular -ectiou. It di-appear-. and a .-welling ' ' nth r end of each muscular section when the current is ill'] -.:".. pie of ;i LiTea! law in regard to bipolar electric ' tioii in -trial ed muscle arises at the cathode de. and at 1 ' : "d.- when t he curreiU is broken. 1 h" p natun if muscular << mi ract i' m is ^ _J ' ;-; OUT:I|)!I l-'iu. -J i:, . The mu-de point and t he i \vo |i ci rode- are applied near : '>< '-Hon lake- place in the half of 1 ' i \\ hen t he current i- m.-ule, ' anode 01 j,,,Hi ive electrode i- apjilied PHYSIOLOGIC EFFECTS OF ELECTRICITY 32'.) F. W. Frohlich 1 finds that when both electrodes arc applied to one- half of a muscle which is fixed at its middle point, contraction takes place first in that half. It subsequently occurs in the other half. Con- traction in the first half ceases, and the process of restitution begins while contraction is still present in the; second half. This partly explains why the greatest muscular contraction is never obtained from a single stimulation. The Refractor]/ or Latent Period of Mn*cnlon which tracings of the units of time, the makinu of the current, and the occur- 1 Hi, HI. f,7. May ti. Km.". MKDICAI. KLKCTHICITV AM) KONTCiKN HAYS rence of contraction in the >ame muscle when the electrodes are applied at two different part- of the motor neives ( Fiir. 247) are recorded. Two separate measurements of the latent period are made, changing the po-ition of the electrode-. The difference, in fractions of a second, between the two latent period.- found in this way is due to the time con-timed in tran-mit tint: the stimulation through the length of nerve between the two different part- at which the electrode- are applied. 1 1 iima n nerve-: transmit impul-e- at the rate of about .">() meters a second. /:,f tin S/iitnil Cord. \\y thi- is meant the time [>ied hv the cord in receiving an impulse ironi the stimulation of a -ensofN nei'vc. and in sending out an impulse through a motor nerve 1 . I' ;- the lime required hv the spinal cord tor the performance of its re' 1 ' \ fund i> ins. I' ired by mean- of the invograph. Kleetrodes from a I'e applieil t.. the motor nerve near the spinal cord and the latent period of contraction noted. '1 he electrodes are then applied to the sensory nerve near the spinal cord, and the latent period of Con- traction is aiL'ain measured. The in- crease m time required in the latter case 1 ] due to the latent period of the spinal cord (Fig. 24S). The latent period of the cord is about : ' ';"" li " f "" ^' ihal twice a ; much as that of the whole lengt h of the nerve. '/'. . Mnxcitlar ll'n n .-- \ striated mu.-cle whose nerve' is stinmlated either at some part oi its course of at its insertion at the motor point of :;iU>c]e -i -i i contracts simultaneously in all part.- if it is in a condition, ('ertain diseased condii ions, prim-ipallv of the thi.- and caii-e the contraction to progress irraduallv ' ' . "H 1 pai-' ii] the mu.-cle in another. I'oi.-onin^ b\- curare also I J "Me. - eftect by paraly/.iii'j: the motor plaques, the terminations '' ' ' fie; ' '":- u]ii in t he individual muscular liber-. ' m d r normal condii ions a wave of com faction t ra verse's ' i ' application ,,| a si in ml us. Thi- i- associated wit h I he wave of com ract ion i- sho\\ ;i b\- means litider. one end of the lever re-t in- upon t he lateral fid in-ii lien the muscle -wells and show- ' con: ract ion has reached t hat point . '" !' d that inu-ciilar com ract ion means .-hort enint!; and o| t he mu-cle a change of fonn, not M e'hange in volume 1 m polar -tim illation \\ ltd the anode t here i- a peri polar /one of a polar area of relaxation. There i> quile the o|)])osito PHYSIOLOGIC EFFECTS OF ELECTRICITY 331 Unstriated or involuntary muscles arc commonly in a state of contraction and show a diminution of t his tonic contraction at t he anode when a constant current is turned on, and a1 the cathode when this current is broken. The muscles of the intestine are examples. Differences in Electric Conditions Produce Differences in Muscular Contraction. A continuous current turned on with gradu- ally increasing strength must he made very strong to produce any contraction. A very weak current, if abruptly made and broken or changed in direction or changed in strength, will produce vigorous contraction. In some cases the direction of the current has an effect upon the contraction produced. Muscular contraction is produced by the variable period of an electric current, not by the constant period of the current, either maximum or minimum. Monopolar stimulation is effected by placing one electrode upon the muscle or nerve while the other is applied 10 some indifferent part of the animal at a distance from the first. The diffusion of the current in The immediate neighborhood of the active electrode takes place about equally in all directions. There is neither an ascending nor a descending current in the nerve 1 or muscle 1 . A muscle responds about equally well to positive or negative monopolar stimulation, but a nerve' or the motor point of a muscle shows a markeel difference between negative and posit ive monopolar stimulation. Contractions Occurring at the Making or Breaking, Closure or Opening, of the Constant Current. There is an anodal openim: contraction when the 1 e'lirrent is broken while the 1 anode is upon the 1 muscle or nerve and the cathoele is upon some indifferent part of the 1 body. The 1 other designations are 1 cathoelal opening contraction, anodal closure 1 contraction, and anodal opening contraction. The- names indicate the 1 active 1 electrode 1 , or the one- whie-h is applied to the muscle or nerve, ami whether the circuit is closexl e>r ope'iied. NORMAL ELKCTRIC KKACTIONS AND DESIGNATIONS OF THESE CON- TRACTIONS ENGLISH. EKKXCII. GKKMAN. Catluxlal orkathodal clos- (Closure, .fermat ure; con- Closure. .Schliessung; ,,r KCC. ES or KES. Anodal opening contrac- Opening, .ouverture AOS. Opening. .Offnung AOZ. tion AOC. Anodal rlnMiii: contrac- AES. ASZ. tion ACC. Cat liodal or kathodal clos- CaET or KET. KST. urc tetanus CaCT or KCT. ( 'at liodal or kat hodal open- CaOS or KOS. KOZ. ing contraction CaOC or K( )('. AOC and ACC arc not far from tM|tiul. and the lat !cr is given as the greater in many tallies of this kind. Ca('( ' is much st rouge r and CaOC much weaker. REACTIONS TO ELECTRIC STIMULATION IN NEUROMUSCULAR PREPARATIONS ;};;_> MKDICAL KLECTKICITY AND RONTGEN HAYS liirht current may be modified '>" rheostats and volt controllers so as to SITVC the -a me ] un >o-e. Having made the proper connections by means of suitable electrodes. a ver\' weak currenl is turned on. and then, alter > inu continuously for several second-, it is turned off. A convenient u ay of closing and openim: 1 lie circuit is by means of a Morse telegraphic key. \\itii the weake>t cm-rents no muscular contraction occurs at any time. A- the stivnmh of the current is gradually increased, ' usclilar ci in! ractii >n- be^m to take ]>iace. ( >ne notes the strength of ; ,. current required to produce contraction when the electrodes are iish placed and when the current is made or broken. Normally, tin weakest current thai \vill ]>roduce a muscular contraction at the <'.' -;-> or turning on of the circuit with the cathode as the active - led to the nerve will not produce any contraction with .(n the current is opened or broken, or with the anode when 1 he circuit is either opened or closed. And with neither the ile or the anode as the active electrode will there be any contrac- tioi ';'.::rr_ r the H.I\V of the current. The fir.-i change thai is noted as the current is increased is that the cathodal closure contraction increases in strength, and that anodal opening coin rad ii >n occurs. I' requires a -till stronger cnrrent to excite anodal closure con- : :.. \nd wit h an ext remely strontr current cat hod a 1 closure tetanus occur-. This is a continued contraction following the closure of the '. ; ml lastinti: an a]]>recial)le lenir'h of time. The other contrac- '::.- i:n-nt i-iTii-d have been apparently instantaneous shortening. i::.r: :' lei; followed by rdaxatiiin. The eff.-ci MI the -t j'oi itTesI current -uiten. "< ' ' ' i- an al)breviation for the -latenient tlsat cat ! i 1 1; , c]i i~ ire coiit ract ion re< pure- a currenl ot at lea-t 5 miliianiperes. Form of the Myographic Tracing. Kadi muscular contraction ' ' ' i he myi iLii'a ; iliic i I'aci nn: They a re a refrad or t ail ; / ' ' /" " . ( 'halite -. lei perat ii'i act in a Vei'V ' i 11 i-lit of i hi ;raphic cill'X'e ! dllteivn; tel ii ,.-. ;V, ,,,, I'll "I ( >. \\ ';- ~. I'in '.i t c, 1" " i i i and the ' ' ' ' ;s- applied ^,__\ ' i:: ' ( ' a I to avoid I he illfllielici o] : a ' ! .' ,. . The effect the I, , ire i- to \,.,-\ | nU ch irai ion. \ id\ of i his a' bet \M-I.JI .", ,-,]),] 1 1 i \ . ),,, fref/inM- ' MO , , 1 1 occiii-. and a i M ( ; t PHYSIOLOGIC EFFECTS OF ELECTRICITY 333 maximum contraction occurs. From to 19 0. tho height of con- traction diminishes slightly, and from 10 to 3S ('. (the temperature of the human body) it rises again to the same maximum, liaising the temperature beyond 3S ('. the muscular contractility is seen 1<> full very rapidly and completely disappear; and at the same time the muscle ceases to return to its original length after each contraction, but tend- to pass into a state of persistent cont ract ure. The latter condition may be permanent if the muscle is not cooled quite promptly. I'LT. L'.")0. Wave of contraction at different temperatures C. (isotouie) (Weiss'. Fig. 250 from (I. '\Yeiss shows the comparative height of muscular cont raction following equal electric stimuli, but at different temperatures. The effect of temperature upon the response of muscle to electric stimulation is modified by the rapidity and direction of the changes of temperature and by the conditions under which the muscular work is accomplished. This is true both of single muscular contractions and of experimental tetanus. 1 Influence of Fatigue. Z. Treves 2 has made experiments which go to show that the progressive diminution in the amount of work per- formed in a unit of time by a muscle under electric stimulation of its nerve is due more to nervous than to muscular fatigue. Influence of Resistance. The greatest height of contraction is pro- duced when a suitable small resistance is to be overcome, such as a small weight to be lifted. Electric stimulation produces contraction when there is no weight to be lifted or when the weight is increased within certain limits, which are sometimes quite extensive. A heavy weight prolongs the period of ascent and >hortons that of de-cent, and with a very light weight the period of descent may be very long. !-J.rt<-nxil>ili/>i. The extensibility of a paralyzed muscle is independent of its electric excitability. K. Overtoil has shown that removal of all the sodium chlorid in the muscular substance renders it completely inexcitable. Motonosuke (!oto 8 has studied the extensibility of muscles paralyzed m this and other ways, and finds it unaffected. I\t/'< ft ( /mn Kexixtdnci In liupiurc. I he resistance ot rupture during contraction from electrization is eoual to the breaking strain of the muscle when at rest, and the contraction when stimulated .]. C'arvallo and C. Weiss, (' is'.l'.i. ;md fisti. .Inly 'J'J. l.sW. : Aivhiv. ill ['isiolojria, '_'. 'J-JT, ; Xcit. f. Hiol.. 4ti. :>'., I'.KU. '.I. C'arvallo aJid G. Weiss, (' IS, l.M'li. 1. titiO. .Juiv lo. MKDIfAL ELKlTHUITV AND RONTGEN HAY: Wave of Muscular Contraction. A muscle stimulated at anyone !><>int u-uailv contract- in every pail, hut I his contraction may not take place everywhere -imult aiiei iu-lv. Aebv ha- ]>laeed two myographic levers at ditVerenl part> of a l"iiL r iinisde and lias sometimes seen the levers move at different limes, indicating the progress of the transverse swelling and longitudinal shortening, which is called the wave o{ mus- cular contraction. Single muscular fiber- ob-erved under the micro-cope show a pro- i:re--ive wave of transverse swelling under the stimulus of an electric cur- rent (Ficular contraction. . iilx r. All parts of the muscle contract at once. The sai.'e is true of stimulation at the motor pi-int of the muscle, since this is really stimulation th:-"UL r h tin nerve at it- p!a<-e of subdivision. Stimulation of a mu.-cle of contraction: and stimulation of a curari/.ed nerve always does. Tip- wave "t contraction in living human muscle travel.- at the rate of about in to i:; meter- a second. S >e pa trench of ; he current. Many circumstances modify thi.- and make the mat hematic application different in the .- forms under which the current is applied, such as condenser irire.-. indiici d currents, and. inierrupteil galvanic currents. 1 Jiffer- eni : >ri\ das have been found hv various observers to corre.-pond clo-i-l\ with the results of t heir experiments under t he-e different con- ..'.:.-. No one -implc formula suilices even approximately for every condition. Sec al-( i pau'e '.] 1 '2. Nature of Nervous and Muscular Excitability. The stimulating ' h ctrici? \ ,pon a nerve or a muscle is doubt less due to a change ti-.-ue, and tin- i- -iippo.-ed to be of the character '.' : b\ ' e term electrolytic ii-ed in ii- broade-i sense. There is . _ . . ' 'f ion- and en-ncc in i e osmotic piv-.-ure inside i he : i lie nerve-tiber.-. ( 'hemic st Hnuli t : duce 'heir ner. ' :; eri i pi MI mu.-cle i- -In >\\ n }<- 1 1 e demon.-t rat ion ' i I' ' '11 after 1 lie a] iplicat \> <\\ has cea-ed. and even : ' ' ' ' ' ' ' _ - li:a\ be \ i-il ,|e to t he mien -n .pe. "' : ' i terve-fiber under ult ra-n i i<'ro-copic e\a nii nation pro- ' 'ii. but no \'i-ible change in t he colloid ainieai-ance. 1 "in/ ' ' : - : \\n -ah- in different animal cell- when it reaches a . ' tin all lUinmoid- .-uflicient 1\ to produce a -tiinula- ' N . ation m nerve or inu-cle. .\ ( rn-t'- theorv is .' : be n ,n idi red a -erie- of cell- -, pa rated by -e'mi- . I i.i osmotic pressure in mu-cle- i- rai-ed -oinetime- a- much as ian ci ntimeti i i i he mu-cle i- ih ; , -t a te of I loli. | |,i , . | ]ri|| i- m'e-ite-1 \\ hen PHYSIOLOGIC EFFECTS OF ELECTRICITY 335 longed and strong. It is, perhaps, the chief factor in the development of fatigue. Application of Electric Stimulation. The stimulation may he applied indirectly through the intermediary of the nerve or directly to the muscle itself. In the latter case the result is due partlv to electric stimulation of the muscular fibers, but largely to stimulation of the peripheral terminations of the nerve-fibers. The effect of the latter may be eliminated by the administration of curarin. an alkaloid which paraly/es these motor plaques. Stimulation of a Muscle or Nerve through the Unbroken Skin ('Monopolar Stimulation). -A small electrode is applied to the surface of t he l)od v over the course of the nerve or over t he muscle, and another electrode, which may be larger, is applied at some distant indifferent part. The influence of the current at the active electrode is greatest near this electrode, and becomes weaker as the lines of force spread out. in every direction through the body. This creates a difference in the nerve or muscle by an electrolytic action, and under certain conditions demonstrable contraction is excited. Point* of Election or Motor Point*. -These are the places upon the surface of the body whore the application of the active electrode; results in the strongest muscular contraction. The motor point of a muscle generally corresponds with the point at which the motor nerve enters it, and divides into its terminal ramifications. Stimulation at the motor point is really stimulation of the motor nerve, but limited to the individual muscle. If the active electrode is small, the current of moderate strength, and the motor point accurately found, the individual muscle may be made to contract, while the neighboring muscles remain relaxed. This is one basis of the use of electricity in diagnosis and treat ment. Chart* of the Motor Point*. -These are more or less diagrammatic pictures of different parts of t he body, showing the motor points according to Krb's classic observations. They are of service as a general guide, but the exact localization is partly a matter of experiment in each case. Degree of Excitability to Percutaneous Stimulation. The normal degree of sensitiveness of the muscle or nerve to the make or break of I he current is t he same as thai given on p. 331 in describing t he effect upon exposed nerves or muscles. The Strength or Height of Contraction. The strength of con- traction under the different conditions of polarity and opening or closure of the circuit follows the order of their appearance as given in the table (p. 331). The cathodal closure contraction is normally the strongest of all. Minimal and Maximal Contractions. Taking any individual phase, such as the cathodal closure contraction, and tracing its magnitude by means of the mvograph, we find that a weak current produces no contract ion at all: that the weakest current thai will excite any con- traction at all produces a minimal contraction, and that as the current is increased in strength a maximal contraction is obtained, which is not surpassed bv further increasing the strength ot the current. The production of the minimal contraction is called by the French the threshold of contraction. Some muscles do n<>t contract at all unless a current strong enough to produce a maximal contraction is applied. 1 he cardiac muscle is '.Wi MKDK'AL KLK( TKK ITY AND RuNTGEN RAYS an example, and if tin- auricle of a frog's heart is completely separated, ii si in n cea-es in heat spontaneously, but may he stinnilated to contract hv an electric current; hut oiilv the inaxinial coinractio!i i> known. ['he effect of a series of stimuli in rapid succession is to progres- sivt:l\ increase ...iit of contraction. There is a limit, however, i- reached in a very -hurt time, and then the effect of fatigue becomes apparent in a diminished hemht oi contraction. |- is the same in regard to the maximal contraction. The greatest if cunt ract i n thai can he produced by a single stimulus is exceeded if successive .-limuli of the strength required to produce a maximal contraction are applied. Fiu. 2~>'2 is a myographic tracing with a slowly ivvolvim_ r cylinder, and stimuli applied at such sh >r! intervals that we i:'et the effect of an increase above the maximal coin racTi'nn from a single stimulus. The stimuli applied are all espial, lull the iiei^ht of contraction increa.-es pro\. nil. I iiif-rca-c t Ii it: ni-1 ' a certain limit in consequence of fatigue. 1 - Lf ").'! . ' pon a rapidly revolving cylinder. Electric Muscular Tetanus. If stimuli are applied in such rapid III >ll ha- Hot ce;--eil bi 'fi il'e t he IH-Xl Ci >n- 1 ' ci iiidii ion uf com inueil emit ract ii in which !:';-. I hi- ci itidii i'-t. doe- not impl\ : he pi-ex-nce nt' 1 he lied tet aim-, all hoti as one of I iii I'paretit . ci ini ract ion ' the tetanus I In mu.-ciilar !;.c '<'.<' I i.M! ' PHYSIOLOGIC EFFECTS OF ELECTRICITY 337 and ;i sufficiently rapid scries or alternations will produce tetanus with very weak currents. The height of the continued contraction in electric tetanus is much great IT t han the maxima] cont faction from the strongest single stimulation (Fig. 254). Xot only is the contraction produced by periodic stimuli stronger than that from a single stimulus, but it is more easily excited. Periodic stimulation of the exposed sciatic nerve in a frog will excite reflex contraction of the muscles of the opposite limb, while the strongest single stimulation will not do so. The Production, of Electric Tetanus. J. ( 'ar- vallo and G. Weiss 1 believe that the magnitude of the successive? stimuli is of greater importance in the production of tetanus than their fre- quency, and that its determination is easier. Both factors are essential, however, in the case of a unidirectional current, as well as in the case of the periodic (alternating) currents from an induction coil. Submaximcd Tetanus of Striated Muwlcs. A striated muscle under- goes a series of uniform contractions when it is subjected to a series of maximal stimulations. A. SamojlofF finds that less powerful electric stimuli produce a series of unequal contractions, and that the inequality does not follow any definite law. Maximal and Submaximal Contraction. The greatest amount of muscular contraction which can be caused by a single electric stimulus is called maximal ntuxcidar contraction. Any smaller amount of muscular contraction is known as snhmaximal muscular contraction. A maximal stimulation is produced by an elec- tric stimulus powerful enough to produce maximal contraction. A series of maximal stimuli from an induction coil produces a tetanic contraction whose myographic tracing is a regular curve: but when weaker induced currents are used, the tetanic contraction makes an irregular and trembling trace. Cooling a muscle causes the tetanus to become regular. A. Basler 3 has shown that the sartorius muscle of a frog is easily put into submaximal tetanus by weak faradization of its nerve, while a much more slowly interrupted or alternated current will produce tetanus only with a current: which is strong en< nigh to produce a maximal contraction. Submaximal contraction becomes a continuous tetanic contraction if the stimuli occur as rapidly as 27 times a second, while maximal contractions do not become continuous unless the stimuli are as tivquent as ;i4 a second. The myographic chart made with between 27 and :->4 interruptions a second shows a continuous fused tetanus with weak currents, and a serrated tetanus with strong currents. Basler explains this on the theory that the weaker current stimulates only the thin, slow, easily excited muscular fibers, while stronger currents stimu- late the rapid fibers which are more difficult to excite. The frog's gast rocnemius muscle does not answer for this experiment. The effect of alternat ing or of interrupted direct currents is to produce exactly the same muscular tetanus, provided the successive alternating ^Journal Physiologic '1 .!. Pathologic, 1, IS'.) 1 ,), 443. 2 Arch. f. Physio*!., oTJ, ivi'.t. 3 Arch. f. .1. ies. Physiologic, 1 ().->, :m. l'.K)4. ;. ;; s MKOHAL KLKCTRK ITY AND HONTUEN KAYS currents :uv exactly similar except as to direction. Carvallo and Weiss 1 have tested ihis fact l.y means of a dynamo of special construction, irivin" uniform periodic "currents, either direct or alternating. Tripolar Stimulation, This consists in the application ot electrode from one pole of the battery, and of a forked electrode or two electrodes from the other pole. The single electrode is applied between the other two. In such a case the forked electrode is the more active, and it will, for instance, prevent the occurrence of elect rot onus due to the middle electrode when the applica- tion is made to an exposed nerve (Fig. 2.~)f)). It affords a means of producing an effect upon a deep-seated nerve without diffusion of the current. Set; of t ripolar si imulat ion. Peripolar Stimulation. This occurs when a small electrode is applied over the middle of a nerve or muscle in an uninjured limb, and ;i larire electrode i.- applied to t he opposite .-ide nf 1 lie limb. In Fig. 2")(i the negative electrode is over the muscle. The direction of the current thro , ii-de i- f roii i hot h ends toward the center. I M" course, all the c:i ;!,! im 1 in- lar.^e indifferent po.- it ive elect rode does Hot u'o to the two end- "I ; he mu-cle, as the diagram would indicate, but ivallv s]reads ''It I!'"! i i;.' :. tde ;il id. enterhm I he liei'Ve or muscle at rnallV different j' >.:. ' ' muscle, t" leave :; chiefly at a point as near ' ! lie cal ho(le. I: ' produced in the nerve or muscle the same tripolar .' liie in t Ve or niil>i-le had been e\po>cd. and a >ini:'le . been applied between t wo electrodes from the Virtual or Physiologic Electrodes. The electric current passing :'.''' . :: 'in either end toward I he center may be regarded : [' ; ' . : >h\'.~ii T 'trie eject ri >de at eit her ext remil y ect rode at i he center. The names virt ual 'r pli ":- indicate iln- place . -it which 1 he current enters I .. |, [] v ,' . i,. I'ntli.il . is'.i'.i - An : / i 1 : . . '. .. ..-. !. r,\7, IV((. PHYSIOLOGIC EFFECTS OF ELECTRICITY 339 and leaves the muscle after having passed through the different struc- tures of the limb from the places where the real electrodes are applied. The real electrodes are the metallic or other terminals from the two poles of the battery. It has already been stated that the single 1 middle electrode in tri- polar stimulation is deprived of much of its effect, and that the outer forked electrode is the active one. This condition prevails to a certain extent in peripolar stimulation and may explain the phenomenon of the reaction of degeneration. Nature of the Electric Current Employed. Variations in the strength of a galvanic current produce muscular contraction the height of which increases with the amount and abruptness of the change in the strength of the current. Induced currents provoke contraction and are very readily applied, either as isolated induction shocks or as the periodic discharge from a faradic coil. Faradic excitability may be lost and galvanic excitability retained in certain diseased conditions, or the reverse may be true. These deviations from the normal yield important information as to the con- dition of the nervous and muscular systems, and furnish indications for the proper electrotherapeutics application. The primary current of a faradic coil is an interrupted galvanic; current with a high-tension element due chiefly to the self-induction occurring each time the current is broken. This form of current may be used to excite muscular contraction. Yon Helmholtz's faradic coil has the connections of the primary coil so arranged that there is never a complete break in the primarv circuit. At a certain stage the current passes through the primary coil in full force, and at another stage a large part of the current is diverted through a shunt <>f low resistance. The object of this is to eliminate the self-induction occurring in the primary coil when the current is completely broken, and make the variations in strength of the primary current equal. The reduction and increase in the primary current being of the same quantity and abruptness, the currents induced in the secondary coil at these two phases of the primary current are equal. A faradic current from such a coil does not have the polarity which characterizes that from an ordinary faradic coil. There is no difference in the effect upon muscles or nerves whichever is the active electrode, while with the ordinary faradic coil the currents in one direction are much stronger than those in the other. CORTICAL STIMULATION Epileptiform Convulsions Produced by Cortical Stimulation. Stephane Leduc 1 shows that intermittent currents of low tension applied directly to the cortex of the brain will produce the group of symptoms typic of epilepsy. He thinks it practicable to study the effect of different therapeutic measures upon this artificially induced epilepsy. .1. 1>. Prevost and J. Mioni'-' have studied the effect of thyroideetomy upon the epilepsy induced in young animals by alternating currents. They find that it prolongs the stage during which cortical stimulation 1 Arch, tie mod. dcs. Infants. 12, 771. October 2.'), HH)4. 2 C. R. dt> Soc. de Biol., 58. *)'., January 14. 1905. >K> MKDICAL KLK< THIelTY AND K(")NT(iKN HAYS produce.- tonic c,,nvul:-ions without clonic convulsions. The adminis- tration of thvroid extract, on the contrary, cau.-es clonic convulsions to f. .iio\v ci >r\ icai M imulat i' >n. /'. - Sti tn /ilfitinn "l' antecniciatus. where stimulation wa.- folloued 1>\ more or less profuse perspiration of the opposite side il the body, la.-i in live or ten ntiiuites. The -ame re.-uh wa.- obtained in a colt by stimulating a center about the -;,:> of a -ilvi r Id-cent piece in front of the motor area. Ligature M] ,. hlood-ve-.-els ' 'f a limb did not ]> re vent sweat in::' when t he cerebral center v, as -t ii ilated. X t -it her did t lie use of curare prevent muscular coin ract ion. Man nit til* tiffin .l/'/.v/i .-: of flu- fci/c front Stimulation of the Cortex < '' Urn >. It, du Hois-Kevinoiid aiul P. Silex 2 have studied this -ultject, and find that in do^s there are three different centers when; electric Mill illation produces movement of the eye. One i.- the visual -pi ere, allot her i.- a point in t he center for movements of the neck, and er i.- in the center for movements of the face. Stimulation of the fir-1 \vi produce associated movements. Stimulation of t he last-named pi-oduce- isolated movements. The visual sphere has to do only with movements which normally accompany the exercise ot the visual funci ion. STIMULATION OF THE CEREBELLAR PEDUNCLES I-'. If. Thielle 1 fiiid.- that this pi'oduces movement principally of the milM'les on i he same -nle ol the bod\\ Cerebellar Localization by Electric Stimulation. (1. Pairano 4 that there tire two special areas, one for the upper extremitv on the same -ide, and the other for the posterior extremity on the same -id'-. The firsl il these i- located at the middle and lateral part of the vi . - : the other, a lit 1 le hack, mi t he base of t he lateral lobe near t he Stimulati 'ii ol these area.- does not produce spasmodic move- ent-. but attil ides maintained by a mu.-cular contracture. The [M.-I ii-e may b<- one nf flexinn or extension, adduction or abduction, iM-les may be involved as to indicate that manv centers are grouped in a very small area. The-e centers are at some little . : : ' . . I co nt ract lire may be modified bv the will. Another lea tun.' ' 'ii oi i he anterior extremity ot the vermi- i> exaltation . ' ' : : terror, but no forced or at axic movements, although r ! '.'.' reaction to noi-cs 01- other -li^ht external causes. |p Itation theiv i.- vertigo, and the dor upon whom tried bark- and whines. ! rom this experimeill it . i the anterior part of the vermis normally pla\'s an important role m the different emotions and in their expre--ion. PHYSIOLOGIC EFFECTS OF ELECTRICITY 341 ELECTRIC STIMULATION OF THE SPINAL CORD V. Decceshi 1 stimulated the spinal cord of a frog l>y means of shocks from an induction coil, and measured the contraction of iho gastrorne- niius muscle. The latter was much reduced if a weak solution of sodium chlorid was caused to circulate through the blood-vessels of the spinal cord. This reduction took place with hypotonic solutions, or those of a strength less than the; normal , fi ( y of 1 percent, contained in the l>lool), 1x99. 342 MKDH AL ELECTRICITY AND RONTGEN RAYS when* stimulation will cause uterine contraction. Stimulation of the dura mater, however, re ("-n forces uterine contractions. He ha- found no such center in the medulla. Loss of Excitability in the Spinal Cord in a State of Degeneration. IV-truction of the motor area in the brain is followed within eight days by complete lo of faradic excitability from stimulation of the internal cap-tile or of the peduncle- of the brain. (Vera Norowska Oscherowitsch, experiment- upon dogs. 1 ) Variations in the Excitability of Motor Nerves. Nerve-fibers undergo chanii'e- in excitability when various salts are applied to them, and thi- change is associated with modifications of structure and color- ability. Effect of Carbonic Acid. Waller' concludes from his experiments that electric reactions in a nerve are increased by small and diminished 1 >y la rsi e < jtiant it ie- of carbonic acid. }'<>i '"/>> ' >."/ firotorcrdtrin have many physiologic effects in com- mon. but yohimbin prolongs the refractory phase while protoveratrin increases the electric variation of a nerve which is stimulated. Studies with the-e two substances lead .1. Tait : to conclude that the refractory period corresponds with the period of electric variation. I 'oi-oninu by oxalic acid destroys the faradic excitability of the vagus nerve in warm-blooded animals. 1 Loss of Nervous Conductibility from Narcotics. General anes- thesia from ether, chloroform, morphin, chloral, alcohol, or other drugs rediice.- i lie conduct in'_ r ])i >wer ot the nerves and may complete! v abolish it. "1 e iattej takes place abruptlv. having been preceded by a certain stair 1 ' ' which the nerve i- easily fatigued by strong and frequent ind [ceil c .'.>:.'-. 'I he same changes t ake place when the n;i ret it ic is tniln nerve, but !'. \\ . Krohlich and J. Tait 6 find that. to it- abundant vasculariu , tin- intact nerve i.- very resistant to -. l.'M-al iti'-xcit abilin i- apparently more easy to produce bv the top c; . a pphcat ion i .i' ;i na rci >t ic than lo.-s of conduct ibil it \'. \ . ' eases the latent or refractory period intervening n tin ajiplicat ion i] a stimtdu.- and the resulting muscular con- 1 . I- Cocain ha- n i-elcciive action upon the different fiber- of a mixed ' laments are paralv/ed before the motor; the - oi the- pneumo^;i-! ric betoi'i 1 the ascending: vaso- ' od :itor-. mid bronchocoiist rictoi> before broiifho- dil ' i i upon t he nerve-fibers, and not like that of curare Up' 'II the i-ni l-p!ate- i ,f t he nerve. 11 n i|i- vui- inTvi'U-i- crntnili- r : p :;'.:; Julv _>:; imo ' C. ,- ill ! .- |'| ..;,,!'. 12, 74."), rvbru:ir\ 4. iVt'.t. I . .; rmirnt il I'hy-iol. nry. iii. L'LM. I'.tlO. 1 I{. ( ; . ' : lili'-h, . \n-liiv fur f\]MTiiiic:iiullc I'lithuluuif and Pharma- . - . 11" 1 '. 1 1 I .1 .-:. : I'! . ' If I 1 Ltd . I'.!!).", ' I );\ HI, .1 .! I ' . ,'._'.. I'.tnl. -\'l. M',. PHYSIOLOGIC EFFECTS OF ELECTRICITY 343 Influence of Fatigue on Electric Excitability.,!. Joteyko's experi- ments upon the fatigue of the nerve terminations' show that these are much more rapidly fatigued than the muscles when an induced current is used. Influence of Circulation Upon Nervous Exhaustion. K. Taskinerr shows by experiments upon frogs that while a muscle with circulation regains its excitability in three to six hours after complete exhaustion, a muscle without circulation, but in an atmosphere of oxygen, regains its excitability only partially. A rapid rhythm exhausts a muscle with cir- culation sooner than one without circulation. A slower rhythm than once every four or five seconds is more favorable to the muscle with circulation. Influence of Traction Upon Nervous Excitability. The electric ex- citability of a nerve is diminished by traction upon it, differing in this respect from muscular excitability. 3 Electric Response of the Nerve to Two Successive Stimuli. Francis Gotch and J. Burch' have made electrometric measurements of a nerve subjected to rapidly repeated stimuli. The nerve docs not give an electric response To a second stimulus unless there has been a sufficient space' of time since the first stimulus. This period varies with the temperature of the nerve. At 4 ('. the smallest interval is O.OOX second: at 2 C., 0.012 second; and at about 15 ('., it is 0.002 second. This has an important bearing in explaining the lack of sensation and motion from the application of high-frequency currents, in which the impulses occur in opposite directions at intervals of less than i.ouo.ooo second. Delay of Electric Response of a Nerve to a Second Stimulus. The greatest delay occurs when the interval between the two electric stimuli is 17| :> - second. 5 And S. Levinson has further experimented with two electric stimuli, the first producing a marked but not a maximal contraction. With intervals varying from 0. to 0.0004 second, the two stimuli reenforce each other. Longer intervals result in a lesser contraction than if only the second and stronger stimulus were applied, and beyond a certain still longer interval the result is the same as if only the second were used.' 1 Effect of Heat and Cold on Nervous Excitability. K. Pretschis- tenskaja 7 has found that the electric excitability of the vagus nerve is tolerably uniform, within quite wide limits. It is diminished either above or below these limits. Heat or cold does not increase its excita- bility beyond the normal. (1. Brodie and W. D. Haliburton s have studied the effect of heat upon muscles and nerves. The electric excitability of muscles and nerves and their negative variation and other electrophysiologic proper- ties disappear at about the temperature of 40 C. in frogs. 47 ('. in 1 C. R. Soc. do Hiol., eleventh series. 1. oSG. May ;_>(). 1S99. - Skandinavisrhos Archiv. f. Physiologic, vol. xxiii. p. 1. 1000. 3 (1. Weiss. C. R. Soc. do Hiol.. 'tenth series, (i. lOo. February 11, 1>>99. 4 Journal of Physiology . xxiv. 417-421), 1>99. 5 P. (iotch. Journal of Physiology, xl, p. 2.10. 1910. 6 Arrhiv. fiir die gesani. Physiologic, exxxiii. 2t>7. 1910. 7 Zeit. f. Kxp. Path. u. Thorapio, 47, s7. p. 97. 190."). 8 Journal of PhvMologv, :V2, 473, 190f>. ;VH MF.DICAI, KI.Kl TRIi ITV AND RONTGEN RAYS mammal-, and ">( f ('. in l>inls. The difference is due 1<> the varying coagulability of the proteid upon the di-app<-ai aticr .-did reappearance of muscular contractilitv. Mare\ - '.'1 a very -lowly revolving myo^niphic cylinder were ; ,-' v. .-.- -tin ulateii by i he -econdary current from an ' ci il. A < . ien-er wa- discharged through the primary of ie\v M'coiids. I his inithiiil <>f i /i rf rifii// '/ xti/i/it- : ; -.- >> , grains v\ a- ' : : tn 4 : e : mi : ! . In a living 1 i'"i: \vit h the sciat !< nei'\'e cut . hut 4 ,i- ci;-i '. iniaiM at - 1 ' tn 2") ('. muscular excitability was practi- 1 e\! i-Iili e. b ;' ;;! !ii>i thei'e was a slight lllci'ease 111 elect 1'ic d by a decrease with a subsequent increase to about original height of muscular contraction. This latter '. _ ' maintained for a very ]im time. Fatigue takes temperature is raised or lowei'ed. It nccui-s very rapidly a' M ( '..''.' I'l'in fact ilit; instantly I'eturns on raisin zero. Effects of Cold Upon Speed of Nerve Conduction. The accepted formula > I.i'ir. K - u lit. <: and l> bein.tr constant> for most tempera- ture-. And at two different temperatures. 10" ('. apart, the ratio is between 1 to 2 and 1 toil. ( 'old. t hen. trreat ly -lows the t ransmission of The ratio i- >imilar to that of the effect of cold upon in chemic reactions \ant Iloff's law . but many exporinicntors ' n-uard it a- a purely physical as di>tiii|iuished from vital phe- Effect of Alternating Currents. A closin.ir and sometimes also :, ;- place when an alternating curi'ent of Stimulation of a Muscle Which is Completely Separated from the Bod v. 'h* til id- that the effect depends upon the portion ' ' current i- applied. The des are Elei trie Contractility of Striated Muscle After Death. .!. Bab- : ci prr-ent a pliiiM- in \\ hich t heir I'i t In liill-cle i- re I ained. '' Volt a ic excit ahilit V > elt'C- a vi : ' ' , ' ' !. T! e rear] i' in i >\ <\ ailiei] : . :. i- ACC i ',-,( ( and ' 'a( '( A< X '. Mai ( - ' ' ' ' ' ' mi result- in t he sum 1 \< .urnal. PHYSIOLOGIC EFFECTS OF ELECTRICITY 345 Stimulation of Nerves by Electric Currents of Very Brief Duration. Louis Lapicque 1 finds that the contraction produced by a very brief electric stimulation is exclusively a closure contraction. J. L. Hoorweg- calls attention to the fact that the muscle is not a mere elect rodynamometer. indicating tho strength of the nervous impulse arising from stimulation of the nerve, but is itself excitable. Knge]- m aim's observation in 1X71, that the ureter which is of nnst riped muscle devoid of motor nerve-fibers, obeys t he same laws of electric; excitability as nerves or muscles which are supplied b\" nerves. Hurdon Sanderson's observation that curarized muscles obey the same laws of elect ru- st inmlat ion as nerves confirms this fact. Hoorweg considers \Yeis.~'s law of electric excitability to be true only of short discharges and that it is in this case deducible from Hoorweu's law. lie thinks YYciss's law leads to error when applied to currents of considerable duration, while its simplicity makes it very useful for cm-rents of short duration. Lapicque's correction for currents of short duration seems unsatis- factory to Hoonveg, because it assumes an absolute constancv of resistance. Tonus Rhythms in Normal Human Muscles. T. A. Storey 3 provoked a series of contraction in the abductor indicis by a magneto- electric apparatus, and made tracings which showed the presence of tonic contractions analogous to those demonstrated by Joteyko in verat rinized frogs' muscles. The same experiment upon a cat whose sciatic nerve had been divided showed that the tonic contraction was of peripheral origin. Apparent Inhibition of Muscular Contraction. The experiments of a number of different observers, including F. H. Hoffman, 4 show that there are no inhibitory nerves to the voluntary muscles. Contraction of Degenerated Muscles When Stimulated by Electricity. G. Gucrhii* has experimented upon frogs. Normally, a series of identical stimuli at sufficient intervals of time produce con- tractions of about the same form and height, but in the case of degenerated muscles the contractions arc unequal, their excitability varying within wide limits. Normal muscles are more excitable; degenerated muscles present the opposite condition. Finally, in degenerated muscles great frequency of stimulation gives a greater contraction at the cessation of the currents than at the beginning (opening contraction is greater than closure contraction 1 ). Drug Effects which Simulate those of Electricity. The clonic and fascicular muscular contractions which are produced by elec- tric stimulation of the motor nerve-trunks may be very closely imi- tated when certain drugs are administered. Hexamin-eobalt chlorid given to frogs, even in very small non-toxic doses, produces this effect. 1 '' I)u Bois-Revmond noted that the centra a neii'a P. \l. dc Hiol., 58, :;i4. February It'-. li0.">.aiicl < '. 1 February _>(>. mo."). Arch, f.'il. gos. I'liysinl.. in:;, \\:], mm. Jour, of I'hyM.ilony. 12. 7.">. I'.to-l. Binlnmx'hrs (Vnt Hill >l;i M . lOo. _",M. I'.MIl. \. Sprriim'ntalc. ">'.. 1^7. 1 '.>."). .!. Mock. Arch. 1'. rxp. Path. u. PJhurmacol.. :!<>. 1H04. 346 MKDICAL ELECTRICITY AND RONTGEN RAYS Return of Excitability After Peripheral Nerve Transplantation. Peterson 1 - reports a case of accidental division of the median and ulnar nerves. The condition five months later was one of trophic di-turbance in the tinkers, anesthesia, eontracture and atrophy of the muscles of the thenar and hypothenar eminences, with reaction of de<:eneration. The end< of the nerves were sutured, interposing I cm. of a do^'s -ciatic nei've. Sensation returned in the thumb in twenty-four hours, in the palm in eight days, and progressively over the hand in tweiitv-one day.-, and the trophic ulcers healed. Motor : returned iii two months. There have been more than a score of such cases, and Peterson states that regeneration is due to the prolongation of axis-cylinders trom the central into the peripheral : i irt \< >n. Setisal ion return- first . Absence of Inhibitory Nerves in Voluntary Muscles. There are probably no inhibitory nerves to the skeletal muscles the ordinary voluntary muscles. The reduced response to successive stimuli is not due to the -timulation of an inhibitory nerve, but is a phenomenon ol ;i-j ie. This i- made up very slightly of a reduction in the con- ductivity of the nerve, and chiefly of a diminished functional capacity muscular libers and a diminished excitability of the terminations nerve, and of the muscular fibers i in mediately after each stimula- tion. Later there is a ret u I'D to the normal, but this takes place the more -lowly the greater has been the fatigue. ? Speed and Duration of Nervous Stimulation. The speed of propa- gation of a nervous impulse after unipolar stimulation is about 26:43 meter- a sect nu 1. The -limulation produced in the nerve is an oscillatory condition la-t mir abi nit ' U K 1 1 :| | sen >nd. Excitability of a Nerve at Different Parts of its Length. Budge and !':!;_>: have noted a diminution of electric excitability toward the peripln-n in motor nerves, but. according to Munk and Schultz, this in: \ have been ijue to iraumatic changes. I. Munk and H. Schultz 8 have arrived at the conclusion that the excitability of the phrenic 'he >ame throughout its entire course. This implies that the ' ner\ His impulse does not consume any sensible amount ol en i _.. uni hence does not produce appreciable fat iglle. iiofT* found thai the excitabililv of a frog's sciatic nerve is top iii bottom for abrupt electric stimuli, but it is twice as L r :'''at above a- below for Lrradually increasing stimuli. REFLEX STIMULATION BY F.LECTRICITY ( i. A. Pai'i lias .-tudied the relation between the intensity of the stimulation and t he hei<:ht of the refill tinu contraction. ( lenerally. the stronire] ilat ion oi a centripetal nerve is, t la 1 greater number of mu-cle-. re-pond reflexly .and the stronger i- their re.-ponse. na- -tudied the fatiguability of the reflex apparatus \i: : ' -I .::..] M.-iljf-M] Sciciiri'-, April. Is'.i'.t. I i' ll"!"ii; ID, Arch, i !. HCMHII. l'h\ -.-idld^ic. vol. mi. p. -J'.ll, !!>()-}. '' -' ' ' !'. <'.!!. Ani'i >ii ->(.. c\\\ an, 1 ii'.. .hine 1 ti Is'j'J :.- .Inly ',',, \^W. Ar li : i'!.'. - -i!.. js], 1 ^'.^ Vri'i, ; . ['!,% MM! . |x\vii. l.'iii. ] s'.i'.i. 7 An-li I :. i U' I'.ii . Sensory and Other Effects from Stimulation of the Cervical Sympathetic. Ch. A. Francnis-Franck 8 has made experiments which . to t he foil' wiim' ci inclusions: 1. Stimulation .>t' the cephalic segment of the cervical sympathetic an vasoinotor and cardiac stimulation (increase in blood-pres.sure mre rapid heart action). Hurt hie attributed this to cerebral . ju-t as in the ease of compression of the carotid artery, but. Fi :.; >i.- I :;!.<;. says thai si imulat ion of this part of the sympathetic - ' n tin es causes the opposite effect of vasodilatation and slowing of e lie rt '- action : and that in either case it is due to a reflex effect from centripetal impul-es carried by the sympathetic 'to the cardiovascular enter- in 4 iie medulla, and not to a direct stimulation of cerebral vaso- coti-t rictors, \\ith accompanying cerebral anemia. The circulatory effect is the same a- that produced by stimulation >i the anterior crural nerve, but it require.-- a much stronger current n the latter. _'. < ieneral circulatory changes are produced by stimulation of the medullary segment of the vertebral nerve, the deep division of the i v.<-::! sympathetic, and these also are of reflex oriu'in. 1. 1 hi- transmi--ion of centripetal impulses from the lungs and ii: b; the sympathetic nerve causes it to be a necessary 1 ii 'he n '"' \ regulation of the circulatory functions. This is a iiM indication to the remo\-.al cf the cervical sympathetic, as soine- ".'- ' 'i tor the treatment of exophthalmic goiter, epilepsy, a, ''ii the theory that its functions were purelv "''' mav, therefore, be either /in ^.^m' or >li f>r< xsor, re-pii'al ory, general motor. pupillar\', and secretorv n i e c a .- e - . ei ' i imulat ion of t he -ympat het ic pi'i uluces ulteii t he effeci i.- a ] ii'es.-i >r one, and then Mil ; ra | in 1 i >r normal. PHYSIOLOGIC EFFECTS OF ELECTRICITY 34! may change in rhythm, frequency, or fulness. There is sometimes a reHex spasm of the bronchi and pulmonarv vessels. This reflex, through stimulation of the sympathetic, may explain the dyspnea which occurs in some morbid conditions of the aorta. The opposite pupil may be dilated. The finders may perspire. There is increased secretion of xalira. As a final experiment. Francois-Franc k cut all the filaments anastomosing with the cervical, hypoglassal, spinal, glossophaiyngeal, pneumogastric, and trigeminal nerves, but left the anastomoses with the carotid plexus. Stimulation of the sympathetic then produced vasomotor effects without the other reflex effects. Circulator i/ Change* from Stimulation of the Peripheral End of (fit Cervieal Sympathetic. E. Wertheimcr and L. Lepage 1 exposed the Fit;. 257. Circulatory effect from stimulation of the peripheral end of the divided sympathetic'. 11, respiration; P, pulse; E, electrical stimulation (Wertheimer and Lepage). inferior and the first thoracic or stellate ganglion. Following the cuttinu of the sympathetic nerve above this point, there is an irregularity of cardiac rhythm, and this same irregularity is found when the peripheral end of the divided sympathetic is stimulated, and also when the intact sympathetic is stimulated. The latter is not so desirable for this experiment, because it produces sensory symptoms and requires an anesthetic. Ejject Upon the Pupil from Stimulation of the Sympathetic. Lowan- dowsky- lias experimented upon both warm- and cold-blooded animals. He finds that in the former, stimulation of the nerve above or below the superior cervical ganglion causes a contraction lasting five to ten seconds, while in cold-blooded animals it lasts very much longer. The muscles controlling the sixe of the pupil are non-striated. The duration of contraction is in direct proportion to the strength of the current. The make discharge from an induction coil either gives no contractions or only short weak ones. The opening discharge gives very much stronger contractions. The myographic curve shows an abrupt ascent and a much slower descent. Vasomotor Effects on the Small Intestine Produced by Stimu- lation of the Central End of the Pneumogastric. : Stimulation of the central end of the vagus in dogs produce^, in some cases, dilatation 1 .lour. l 1S'M>. L't. 350 MKDKAL ELKCTKICITV AND KONTGEN RAYS or constriction of tin- intestinal blood-vessels. In cither case there is an increase in tl lt . oyneral blood-pressure. hut the vasodilatation may he obtained even when the blood-pressure is maintained at a constant level !>y hydrostatic means. It' the splanchnic nerves are cut, stimula- tion of the central end of the vagus is not followed by vasodilatation of the intestine. In a cat. stimulation ef the vagus always causes dilatation of the in'e-tinal vessels, accompanied by a fail in the general blood-pressure. Stimulation of the Pneumogastric and its Motor Effect on the Small Intestine. 1). Courtade and .1. F. Cyon 1 find that strong stimu- lation of the pneumogast ric nerve in the thorax produces a contraction of the longitudinal muscular fibers which is followed by their relaxation, :ind later by a contraction of the circular fibers. This contraction ;'"' -- in character of progress and in rapidity from the effect produced ':>. st imulat ion of T he sympat het ic. .1. !.. IV;nch 2 obtains the same results by stimulating the pneumo- L'a-' ric in the neck. Reflex Vasodilatation from Stimulation of the Sciatic Nerve. I. X. !'v-t renini' 3 made experiments on cats and dogs. He found that electri/ation <>f the sciatic nerve by a current of medium intensity is foll<,wi'd bv vasoconstriction, while weaker or stronger currents produce vasodilatation. Stimulation of the peripheral end of the sympathetic, at the level ij the fifth or sixth lumbar vertebra, does not produce vasodilator effects, contrary to the opinion of Ostrooinov. Motor Effects Upon the Stomach from Stimulation of Different Nerves. -I). Courtade and J. F. Cyon 4 find that: 1. Stimulation of the intact pneumogast ric. or of its peripheral end ii it i- divided, causes contraction of the longitudinal fibers, then of ' ' . ' circular fibers, and t hen a per KM! of rest . There mav be a relaxation "' '.'. circular libers at the cardia and pylorus, simultaneously with the c >nT r;ict ion ol t he longitudinal fibers. Stimulation oi the peripheral end of the great splanchnic arrests at the s a me tune caii.-e.- tonic contraction of the circular ';b>-rs. .-;. . the cardia and pylorus, and also relaxation of the .. :-. I'.'Ji'f "< It'll f-.li ctr/ztit/iin <>f Hi Stninncfi I /mn itx Secretory Activity. \\ . ! reund find- t ha t t hi- doe- not effect t he secret ion of gastric juice, - a moderately increased mucous secretion, which is more , ,r If--, -t p .nu!v alkaline. Effect of Direct Stimulation of the Heart. KjJf Intracnrdiac I.' I' 1 I'urreni from two ordinary voltaic cells and the extra nl ti'om a -mall electromagnet, ]a--ing between electrodes placed ( !.'..- : I'.IM!.. tent), -.TIC-, ii, _':,. .I.-uiuitry, Is'.i!*. .! v XV . L'2. IMW. ' N- '- \--ll irk. 1'J. L'^J. ill. t ,1, ['ntli.il Ccn.. 1.". IVKi. ' Ar- !: i Pit! \!i ,t \i. I'hv-inl.. ]MI. i';;s. Ktn.",. PHYSIOLOGIC EFFECTS OF ELECTRICITY 351 inside the ventricle of a horse's heart, has caused almost instantaneous death. This happened in an experiment by A. Chauveau, 1 who was studying the movements of the valves of the heart. A thin insulated stem was passed through the carotid artery, aorta, and aortic valves. It contained a spring which closed an electric circuit when pressed upon by the contracting valves. This current actuated a small electromag- netic signal, an extra or self-induction current from the. coils of this passed through the blood in the ventricle, when the aortic valves opened and allowed the contact to be broken. This occurred at each pulsation of the heart, which was tremendously accelerated, and the animal died almost immediately. The currents were so weak that they could not be felt when the tip of the tongue was applied to the point where the contact was made and broken. The fatal effect upon the heart was prevented in further experiments by establishing a short circuit for the extra current at each make and break. Effect of Induced Currents. Tetanic contraction was produced in Danilewsky's experiments upon different warm-blooded animals. 2 A living rabbit's heart was isolated by Langendorff's method, and hot Ringer's solution saturated with oxygen circulated through its coronary arteries. It had its apex in contact with two electrodes from an induction coil, giving currents perceptible to the moistened finger. The heart was in a condition of lessened vitality and extremely sensitive to currents from an induction coil or from a magneto-electric machine. Weak or medium currents produce a tetanic contraction of the ventricles, while the rhythmic contraction of the auricles continues. This contraction may be maintained for two and a half minutes, and is followed by a pause succeeded by a very ample systole. Stronger or more frequently interrupted currents do not produce as vigorous con- traction or as complete tetanus. It is extremely difficult to produce tetanus of the heart with the latter in xitii and uninjured. It may be obtained, however, when the refractor}' period (or latent period of muscular contraction from electric stimulation) is diminished by poisons or pathologic changes, or when there is hyperexc it ability or hypodynqmia. A. Bohme's experiments 11 upon a frog's heart whose electric excita- bility has been destroyed by chloral poisoning show that it is restored by camphor. Experiments by Fran/ Mil Her 4 show that, in human beings suffering from tetanus or lock-jaw, there is no electric hyperexcitability of the heart. This organ differs from the striated muscles, such as the dia- phragm, in this regard. V. Duchesi's experiments'"' upon a frog's heart slowly poisoned by phosphorus show that electric excitability diminishes very rapidly, as well as the height of the contraction produced by electric stimulation. The heart may be made to pulsate by direct electric stimulation, even while it is in a state of arrest from electric tetanization of the pneuinogastric nerve. M. Stasser" performed an experiment upon 1 Journal %. lOOo. 3 . Journal 9, 1005. ;}.Y2 MKD1CAL ELECTRICITY AND RONTGEN RAYS ,!,,_, ;in ,l rabbits' heart-, one electrode on an auricle and the other on the correspond iim ventricle. An isolated induction shock causes a svst -lie contraction orrurrimr simultaneously in hot h. but preceded by :l ' ;.;-,:, ,,; refractory period of ii.Uii second. The same stimulation both electrodes applied to the aui'icle causes an auricular pulsation : , latent period of n.mi second, and this is often, but not always, ,vd n. us ',,[ 11. TJ second later by a ventricular contraction. Ap- -tiniiilus to the ventricle it takes three times as long for the sub* . iar ci nit ract \> >\\ to occur. T. Philips 1 has made an experimental study of the fibrillary tremors pi ; . .,,j ; n tin heart by electricity. Ib' found that fibrillation of the irides produced by direct stimulation does not arrest the ventricles, i, , ^ives them a disordered rhythm (Kronecker and Spalita do not -_; v. ;':, this statement). He found that as soon as the auricular <:,.,,; Drives place to regular contraction the normal ventricular rhythm i- resumed. Stimulation of the pneumoiiastric prevents the occurrence Iar librillat ion from electric stimuli (this contradict? Kronecker and Spalita). and also the disturbing effect of auricular stimulation vein rides. M'i'f tin /i)t< a moijasfric itihihit* the ( tnct of direct .'-- , ifiiitt t>t'tln i'i/i/i. iinil c- loim the ensiiim: diastole. The same effect is produced by stimulation oi a heart poi-on.-d b\' ati'opm. Severe n icoi in-poisonint in a doir -e- the electric excitability of the heart and makes it more per- ->':.'. /,'.-''.; t'urdiiir Slim >i}it ux Moilit'nd li>t Cirtnin I 'o i *o n * . Under ': >rmal conditions, stimulation of mo-t of the sensory nerves leads to a .: :;:-> ;u cardiac enersry. Thi- can be accurately measured increase m the bloo(l-]>ressiire m the arteries and its r> d'icT ; ,n ;n tin- left auricle. ]'. \V inkier* ha- foiiml that while st imula- ' '' >: ' ' .- erve in a healt hy animal increases the \\-i rk done by ' li -.''l per cent., 'here was an increase of only 1 \(\ per cent. ! poj-oiicd by muscarin ftoad-stool poisoiO. Sodium '. ' ' 'in n-duce-; the reflex cardiac stimulation, or it may evi'ii r-- . n re(lc\ reduction ot cardiac ar-tivity \\ln-n the sciatic i- -ti::.u ';. \nd under the influenre of am\'l nitrite electric stimulation produces a reflex enfeeblement of }."> to 7"> per cent, in the It doc's not slow the tachycardia of amyl nitrite. -lo\v the normal puUe; and it increases the tachycardia nit nt e and increa-e- t lie rapidity of t he ext remelv slow-beating 1 1 - o 1 1 1 1 m . Electric Stimulation of a Nerve-center, or of the Spinal Cord, or of a Nerve. I I the function of the part stimulated, and a mus- 1 ular [iiovenn i en-ation or -nine other effect i- produced. PHYSIOLOGIC EFFECTS OF ELECTRICITY 353 Applied to different parts of the cortex of the brain, it has given us the most valuable and minute localization of brain function, and applied to the different other parts of the cerebrospinal and sympathetic nervous systems, it has decided many problems as to function which were not to be determined by experimental physiology without the use of elec- tricity. The varying physiologic effects have a direct bearing upon the therapeutic use of electricity. Stimulation of the olfactory centers in the brain causes the same disturbance of respiration that is produced by the inhalation of ammonia and similar substances. Dyspnea may continue even after the stimu- lation has ceased. 1 Electric Stimulation of the Optic Nerve does not Produce the Sensation of Light. This is the surprising result of a series of operations upon six different human patients in whom the optic nerve was laid bare as the result of operations or injuries and subjected to electric stimulation. Other stimuli, chemical or mechanical, gave the same result. 2 Electric sensation is quite distinct from that of pressure or heat, etc. A tuning-fork may be used to produce vibratory pressure and at the same time to transmit to the skin a faradic current for which the tuning-fork acts as the primary interrupter. The patient should be able to tell the difference between the pressure of the tuning-fork alone and when the electric current is added. Arrigo Tamburini has con- structed an apparatus, called the polycesthesioscope, by means of which sensations of warmth, vibration, pin-prick, and electricity may be tested separately or together. 15 y. Duchesehi, Archive Ital. do Biol., lii, 1S3, 1910. - S. Culdero, Archive di farmacologia sperimentale et scienze affini. x, 11, 1910. ; Rivi.sta sperimentali di Freniatri e Medicina legale delle alienazioni mentali, xxxvi. 977, 1910. ELECTROPATHOLOGY 'I'm: harmful effects of elect nViiy upon the human body have been observed in cast's t" lightning-stroke, accidents from contact with conductors charired with high-tension electricity, and undesirable effect-; from therapeutic application of electricity. Manx" experiments have been made upon animals, and have given us an exact knowledge, of the danger- and of the mean.- required to make safe use of this invaluable anencv. The effect- may tie anatomic or functional, general or local, and may be immediate or may not develop until later. The maximum effect i- death. Lightning-stroke. The mechanically dest ruct ive results seen when a tree i- -truck bv liirht ning are thought to be due to the sudden explo- -ive e\ pan -ion of trases. These are generated partly by simple vaporiza- t ion from heat inu of t he fluids in t he pores of t he vvood. and parti}' by the electrolytic decomposition of these fluids. A man struck by lightning i- not tom into piece.-, but the same disruptive effect may occur and produce iri'MS.- or microscopic changes. The gross changes occur as area- of de-tructive extravasation in different organs, and upon the surface at the place- where the electric discharge entered and emerged from the body, and constitute the well-known lightning figures which have . e to the most extraordinary theories in the scientific as well a- in the lav m i nd. 1 he tu ic ro-copic effect s are of a cor res p< Hiding nature. L'ljlif/, * mi F njtirt N. -Markings are found upon the surface of a person who ha- been struck by lightning, and these often have a branching appearance, -u^ne-t ive of the trunk and limbs of a tree. A thirty-one-year-old man. -truck by lightning and thrown to the irround. -tated that he did not lo-e consciousness; could not move his " ' '-''' I" 1 \\'a- -truck. The lightning "" -. The deeper burn- of the first " lorinuof the-kin. whicli appeared eight 'Mm- gradually darker. Thi- piu-mentation " '''' y-'ar- after the injury. Mu.-cul ;ir weak- ELECTROPATHOLOGY 355 ness remained for several weeks and no internal injury was evident. A year later he could work very well, although the left leg was weaker, and before each thunder shower he felt pain in both legs and in the lumbar region. The left leg, and especially the top of the foot, was slightly bluish in color and felt cooler. There was increased patellar reflex on the left side. Other cases have occurred in which a resemblance' to other objects has been noted, and a man is now being exhibited in public places in America whose back is said to show a very striking picture of a crucifix in consequence of a lightning-stroke. The explanation offered in Rockwell's excellent book "(Medical and Surgical Electricity," p. 1(>0) can hardly be accepted at the present day. It is as follows: "The explanation of all these cases is the same. The particles of the tree reduced to great fineness by the electricity are mechanically transported and burned in the skin. The process is, therefore, not chemic, but mechanic and thermic." The utter impossibility of this explanation lies in the fact that it requires us to think that particles from small parts of any individual branch of the tree, instead of flying off in all directions into space, fly right straight to a particular spot the size of a pin-prick on the surface of the patient's body. Particles from a branch four inches thick and fifteen feet long would, accordingly, have to reach the body only along a narrow line a few inches long. The particles formerly supposed to be emitted from the trunk, branches, -md even individual leaves would certainly produce a general blur, particles from each part of the tree affecting the whole surface which the particles could reach. There is no suggestion possible of a lens-like action in this case. The correct explanation of these lightning figures seems to be that they are anatomic changes, erythema or extravasation, produced by the electric discharge applied at a certain part and extending into the deeper tissues or following the superficial tissues along the lines of least resistance. The latter lines depend partly upon the place of exit of the discharge and partly upon the direction of the blood-channels and other paths of comparatively good conductance. Then, again, the path of such a discharge of high-tension electricity starting from a point and extending through a medium which is not homogeneous has a natural tendency to be radiating and to branch and subdivide. A static spark applied to a photographic plate (pp. 47 and .">()) illustrates this tend- ency in a beautiful manner. In some cases the lightning-stroke does not cause branching figures, but simply a discolored surface. The surface marks in a case of lightning-stroke do not necessarily correspond with t he severity of the symptoms produced. These depend upon the organs which happen to t'oim the conducting path between the places of entrance and of exit for the discharge, and may be death, loss of consciousness, deafness, temporary or permanent paralysis of different parts. Death from Lii/htnhifj-xtrolci . This is general!) accompanied by demonstrable lesions in the central nervous system, extravasations ot legration. The person is usually rendered without pulse or respiration. I1V may >r ma\' respond for a while to appropriate MKDK AL KI.F.l THICITV AND KONTCIEN HAYS '/'/> nfim nt af LiyhtniiKj-xtrol:*'. As it is impossible to say from the condition of the patient immediately after the shock whether or not there are irreinedialile lesions, an effort at resuscitation should he made in everv case. \\ rapping the patient in dr\' warm blankets, performing artificial respiration with the patient recumbent, and a certain effort at cardiac massau'e bv intermittent pressure applied just below the border of t he rib- are most important. Hypodermics of cardiac or nt her -tiinuhtnts may he ^iveti. but it is important here, as in every case in which t he circulat ion has practically ceased, not to give an overdose. If one were to continue to Lnve repeated injections ot strychnin or [in hecau-c ii" effect was noted, so much miirht be given that if the heart did -tart up au'ain and carrv all these several doses into the lation. the patient mi^lit be poisoned. Do not administer more than the proper total amount of a powerful drug in these cases, even if t here i- no percept ihle response to it. The que.-.t ion of the employment .". as a means of stimulating the diaphragm <>r the heart mav he ci >n-iderei 1 in individual cases. The Pathologic Effects of Static Electricity. The high-tension ciim-iit- produced by the static electric machine.- have such small tity that the .-hocks they give if carelessly handled are incapable : , iriiui serious pathologic lesions or even serious symptoms. While ti,,. effect of startling the patient is undesirable, the muscular contraction excited bv a static .-park is not of a painful character and L- only momentary. A -ingle static spark does not produce any chantre : 'i the tis.-ues. but a number of sparks applied to the same spot in a continuou- stream will produce ai first a white swelling of the skin from edema and this is followed by redness and in extreme cases by veMi-aiion and other evidences of a burn. The effect on the tissues is v a local one, and is sometimes produced purposely as a counter- ' mt. Its accidental product ion is to be avoided. For instance, in ::r_ r the wave-current or the static induced current, where one or h '. electrode- a re fixed in position upon the skin, it is important That .,d be a perfect conducting contact. If there is a place at c invnt has to -park across to reach the skin, a slight burn > in lie produced. a per-oti -iiould accidentally receive the full charge of a static .'." :>' touching the two poles at the same time, there would be a ' ' :,- arms as t hey were involuntarily drawn awav. but 1 ' - ' : ill- fe-tj!t . oi i-li ctrolysis need not be considered in connection pa'iio i fleets of the very briei and (jiiantitatively small ' ity, tlioiigh it i- true that they are unidirec- iduce a certain -mall amount of electrolysis. Manner in Which Electric Accidents Occur. The proverbial ion i- all important here. Many lives mav be saved eroii- electric contact-, which very often cause m -pite of the nid-t -kilful treatment, after an .!< Ilinek, in hi- "Atlas der Klektropathologie," the many wa\> in which accident- have actually ou-e t here -hould 1 >e ii o bare wire- or uncovered -hould be in a covered case. When it is h part of the electric li^ht circuit . one should ee that he i- not - - 'j in a wet place or upon metal of any kind: he ELECTRO PATHOLOGY 357 should use only one hand, and should not at the same time touch any metal or anything connected with the electric-light circuit. If one Fig. 259. 220 volts direct current short circuited; superficial impregnation of the skin of the hand and of the face with particles of metal. The current should have been turned off before he began to do this work (Jellinek). hand happens to touch two oppositely charged surfaces it is disagree- able, but if both hands do so it is dangerous. And the same is true in MEDICAL ELECTRICITY AND RONTGEN RAYS reuard to touching an electrically charged surface with one hand and niakhm a ground connection at the same time. in electric laboratories and power-houses there are many bare chan.:-rd -airfares and the currents are often of high tension. The attendant- should, of course, be instructed in the danger of touching nlt- l>i;iih with ;i|ij)c;ir;iiicc i,f ~yih|jlfini- of .-:n-t [,;.i i!\ -I-. 'I'lic-r.' wa- :i -liu'tit mark lik.' a i i v, i -. I if It ml i-ij | if rffft l.\ rial ur.'tl. No ot her inf'l ' it tlii cut ui>n- inadf mechanically ami -nr.'i ^ .li'llnifl.i. ELECTROPATHOLOGY 359 form of dry wood covered by a rubber pad, wherever an attendant has to stand while lubricating or cleaning, or regulating any part where there Fig. 2(j:5. Alternating current, 10,000 volts. Death after taking three steps for- ward. Burns of the hack and the right arm: no postmortem changes to he discovered (Jellinek). MEDICAL ELECTRICITY AND RONTGEN HAYS near any live >urface. Of course, a "live wire" should not be touched, 1. in the' danger i- obviated when 1 he man is insulated from connection with the ground or any metal or liquid. 1 in. _':.). --. \lirniatiim current, KXK) volts. Burns of the finders of both hands; cried f,,r h.-lj,. vva- quickly freed fiom tlie contact, and wa.s able to walk with assi>tance. The man mad'' a i:ood recovery ( Jellinck). Danger from Ordinary Electric Lights and Telephones. An electric lamp or a telephone should never be touched with one hand while the 1 hi' fiirri'iit entered at tin- forearm and . II' remembered the oceiirreaae, and rriit u ;.- rin (.IT |,y an automatic break, nd he v,:,- able to <_'o home ELECTROPATHOLOGY 361 within reach of a wash-stand or bath-tub or any metal rail or the like. The slightest displacement of one wire or the other in an electric-light Fig. 267. Electric engineer. Alternating current, 220 volts. Right hand reddish- hrown burn. Eyes only saved by the eye-glasses, which were flecked with particles of metal burnt into them (Jellinek). Docket may convert the exposed metal part into a charged surface, giving only a disagreeable shock to a person who is insulated, but dangerous Fit:. 2fix. Alternating current, 220 volts. Called for help and told them to pull out the contact pluiz at the wall socket. Left-hand fingers all burned. Right hand showed no changes until sixteen ihivs later, then flat while nrcrotic areas. Xo other svniptom.- 01 lesions (Jellinek). to one through whom a ground connection takes place. The same danger is liable to occur from the telephone if a telephone and electric MEDICAL ELECTRICITY AND RONTGEN RAYS wire have become "crossed." Rubber -loves and the various other urerautions must be insisted upon in all work upon high-tension wires. I , , . : - t-lcctric lump -ockd with one hand and the metal fixture with tin Death from Electromedical Apparatus Actuated by the Electric-light Current. \ \\:i~ reporiei] i<> ihc autlioi- li\ I )r. .1. \\illard I . ,Iilli< 17 I'.ll'.t. ;ilid iicrlllTcd Ih |)n\c|-. N. .1. ,\ >tl'Oll^ yoilll}i' ',', I'll i \ci pi 'MI -llji'lil 11 M liuc-t K ih . ;i p plied .'. di!i ' -' ;itci I Hi a /,l!ie-lmei| t i;i t li mi > full of \vat el' !';!. linn 1 1 , i )|i M )( ,11 MI |. People in I he hou>e heard thi-n ;in oiiierv. TlnA 1 |p]'<)kc into the room in'. 1 ;i ''". -li'jht rno\ ciiicnt- ;UM| the vil iral or ELECTROPATHOLOGY ><>> lying on his chest where then; was a burn. The tub was so short that even in his relaxed condition his head rested on the upper edge, not in the water. His friends pulled the vibrator free from the alternating current electric-light socket, receiving a shock in doing so. He died almost immediately. No other marks were found upon his body. No fuses blew out and there was no evidence of anything but the 110-volt alternating electric-light current having caused his death. The body showed a slight burn on the chest about fourth rib and interspace, red and soon became very dark, the body was mottled in appearance, but showed no other burns. The water was draining out of the tub, his foot having evidently pushed the plug _out in an involuntary move- ment. His body was thoroughly grounded by the large surface of contact with the water and transmitted a fatal current from contact with a charged part of the vibrator. If he had been standing in dry shoes 1'iii. 271. Man killed by 110-volt alternating current from vibrator applied while in a bath-tub. upon a dry floor so little current would have been transmitted as to have produced only a slight, disagreeable sensation, or none at all. The Author's Experiments Upon Electric Accidents. Experiments by the author have been with galvanic, faradic, and sinusoidal apparatus actuated by the electric light current with which a patient ordinarily receives from the two terminals a suitable strength of current regulated by a volt controller and a rheostat. It may happen that if the patient is grounded he may receive from one terminal the 110 volts electric- light current unmodified by the volt controller and rheostat as it would be if the circuit depended entirely upon contact with another terminal for its completion. It would be dangerous to apply an electrode from such an apparatus to a person in a bath-tub or otherwise efficiently grounded. If such currents are to be applied to a patient in the bath, the apparatus should ('specially be designed to prevent the patient from MKDK Al. KI.K( THKITY AND KO.NTtlKN HAY; receiving the unmodified elect ric-light current even if he is grounded. In some apparatus this is accomplished by using the terminals of the secondary wire of a transformer having no electrical connection with the primary which alone receives the electric-light cm-rent. This solution of the ditliculty is practicable with the alternating but not with the direct elect ric-lin'ht cm-rent. "With the latter safety may be secured by sutiicient rheostat resistance in each branch of the circuit before it reaches the apparatus at all. No such danger attends the application of these currents from apparatus actuated by ordinary galvanic or storage bat lories. Relative Conductivity at the Contact Between a Shoe and Various Surfaces, Wet and Dry.- Result of experiments by the author May 12. l!U'.'. 1 identified one of the direct electric wires as the charged one and found its voltage as compared with that of the earth to be 110. Through a -cries socket and a 2">-watt Mazda lamp this wire was con- nected with one terminal of a milliamperemeter. sufficient rheostat re- sistance was introduced to protect the meter from an undue strength of current and the shoe from being burnt. And this rheostat resistance was not varied during the course of the experiments. A win 1 led from the other terminal of the milliamperemeter to an electrode consisting of a carbon plate, about the length and width of the foot, which with a moistened pad was stuffed into a shoe. The latter was not new, but had been half-soled. The shoe rested of its own weight upon the surfaces described and the milliamperementer showed that the strengths of current described passed through the shoe to the earth. Dry. Dry. I )ry Dry. \\V-t. \\. ' \\. \\ Dry wood floor one story above the ground. Dry tiled floor one story above the irrouiid. Dry cement floor upon the ground. U et cement floor upon the Around. The Mime dry cement floor. The Millie uet cement floor. i )ry i iled floor one story above the Around. 1 )ry v, ' ""I floor one story above the ground, \\Vt |j|,.,| f!,,,, r ,,,,,. vtory above the milliamperos. Grounding one pole of a battery, static machine, or any other gen- erator n , carrvinu a eouduct ing wire to anv metallic KLKCTKO PATHOLOGY :ili5 object which is connected with the earth. The eartli is so large and such a good conductor of electricity that it will immediately receive and distribute in many directions any ordinary quantity and quality of electricity. The part of the conductor in immediate contact with the earth becomes of zero potential and may be handled by a person in contact with the earth, but not by a person in contact with the other pole of the generator. The difference in voltage between the poles of the generator remains the same as before, though the absolute 1 voltage of one is zero and of the other twice the value that it had when one pole was -f and the other . Grounding One Pole of a. Step-down Transformer. With certain electrical services this should always be done before 1 the alternating current electric light wires are brought into a building. Then if any defect occurs it is impossible for the 550 volts transmission current to charge that wire at all or the other one with more than 225 volts. A shock from the latter is not dangerous ordinarilly. while one from the former may well be fatal. But with certain other services grounding the secondary may be dangerous. "Where a normal voltage in excess of 250 is possible between any wire of a secondary circuit and ground, it is doubtful whether the sec- ondary should be grounded, because shocks to ground from such a system might cause death." 1 Grounding one pole of the battery or other generator for teleg- raphy and also one pole of the telegraph instrument, so employing the earth as a return, is well known. It is an element of safety in case of lightning or crossing by the high tension wire. Grounding one pole of the static machine and the high tension circuit for ignition in an automobile (page C>()'i, and in wireless teleg- raphy (page 1 5(>7\ and of an .r-ray generator (page 1 782). and ground- ing lightning rods (page 226') are important applications of these principles. Pathology of Very High-tension Industrial Currents. The electric transmission of power for long distances is most economically effected by the use of an alternating current of very high voltage. The power for all the street-car systems of the city of Buffalo is sent from Niagara Falls, about fifty miles away, in the form of an alternating current of 00,000 volts. The weight, and consequently the expense, of the copper conductors required for the transmission of the required number of horse-power in the form of a current of (>00 volts would be 100 times as great. The higher tension current is, therefore, used for the long-dis- tance transmission, and is reduced to the utilization tension of 550 volt> by suitable transformers in the city where the power is to be used. The tension of (>0,000 volts is so great that it will spark across an air space of a do/en inches, and the ;imperage carried by these 1 con- ductors is very great. It means death undeT most circumstances to receive 1 a discharge from one 1 of the'se 1 conductors, and so they should be guarded in such a way that no one can come near them. The lesions produced are very much the same as those 1 produced by lightning: burn- at the> point of e'ntranev and of e>xit, and areas of elisintegration and ex- travasation in the 1 organs traversed by the ctinvnt. [If both wire's we'iv touche'el, death would be' practically certain unless the' two points ot 1 American Electricians' Handbook. Terrell Croft. Mc(lra\v it Hill Co.. New Y r\ an9M. otiti Ml.DICAI. Kl.KCTKK l.TY AND KoNTCKN KAYS contact wciv clo-e together and upon the same limb. Kven then a terri- ble burn would In- produced, with ]>rolial)lv ]>enn:uicnt impairment of Usefulness in the limit. If the man were holding the wire when the eur- : :/ \\ us : urned on. muscular contraction would cause the hand to grasp 'he wire with a e pract ii-alh' sure death for aiiv one else to try to release him except bv promptly turning oft' the current. 1: Hilly one win- is touched, the current emerges from the body at i he place where a connection is made with the ground. And the iirreni traversing the body will depend upon the nature ' >l tiiis Around connection. A man wearing dry rubber overshoes and standing upon n dry wooden flour would receive less current than if he were standing upon a metal floor and had nails in his shoes. Then, arrain, rubber Cloves would diminish the strength of the current. But with an alternating current of (ill. 000 volts these would usually all fail to prevent a fatal accident. There is probably no way in which live wire.- a' this voltage can be safely handled. Death occurs from irreparable lesions in the central nervous system paralyzing both re-piration and circulation. Treatment in accidents witli such a volt- age i- u'-ii'-rallv unavailing. High-tension Currents of 1000 to 10,000 Volts. These are alt. -mat inu r currents employed in power transmission, and accidental ' it with the conductors i.- usually fatal. Here, however, the '< :.-: -M i- so much less than in the case of lightning and of the currents of tin. iii 111 volts that many of the circumstances already alluded to may previ fatal amount of current from traversing the body. The mj inc.- produced by the full strength of the current passing through 'he bod} from head to feet are similar to those from lightning or the Hi 1. 1 M M i volt.- current: burn- at the places of contact and areas of !i-itite'_rrat ion mid extravasation, especially in the central nervous ' . !: results from destructive lesions in the circulatory I :.' bod} ; ay form a complete short circuit between the two wires intact with only one wire ami the ground. The current is i lull t In bod} from "in- hand to the other miirht be fatal, be rec i\ ered from. It has a tendency to produce muscular irrippinu of the wires and respiratory i-. ( M her portion- may be traversed bv a current " Us are taken in resuscitate the patient from 'o the nervous system, recovery may take place with '. : . ' t of cert a in muscles < >\ organs. -ame as recommended in case- of lightning-stroke. ce t hat these cases should be 1 reated as if iiitiedli} the. -hock: riot L r iven up as dead without 1 a' ioii. I .; t or the respirat ii in may all e\te) ' ; - never -poll t alieoiisl V to renew their ' ' ' 'il In iii : condition to be -aved by art ificial . tii . ni-. re- pi rat i >ry paralv-is I ejnelil : '.:: ' ill -nine o| 1 he.-e cases one is t niC I A en -i]c]| element - as ' . ' tin \ id in, and the coiidit ion of the a del. effect ni path of KLKCTKOI'ATHOLOGY 307 the current through the body and the 1 quantity which readies particular organs. Electrocution, An alternating current of 1700 volts from a dynamo applied by means of metal bands passing around the head and the ankles sometimes requires several applications before life is extinct. These are of only a few seconds each and the entire process occupies (inly a very few minutes. It is probable that complete insensibility is produced instantaneously, but involuntary muscular contractions and the fact that more than one application is sometimes required make it a distressing sight for those whose duty it is to witness it. The different elements which prevent a good contact with the body or pro- vide a path for the transmission of the current along the surface of the body instead of through it are responsible; for occasional unsatisfactory results. Death is due to respiratory paralysis and it is in cases in which respiration begins again that additional applications of the current are necessary. y. Jellinek has written a monograph on death by electricity, 1 in which are found pictures of the gross and minute lesions occurring in the brain, cord, and different viscera. Death front High-tension and Low-tension Currents (see also pages ~)3() to 537). High-tension currents cause death by respiratory paral- ysis, low-tension currents by cardiac paralysis, if they cause 1 death at all. This is true in general, but, of course, a current which has a high voltage at the terminals of the dynamo may be so modified by the circum- stances surrounding the man who accidently receives it that only a fraction of that voltage is applied to his body, and the heart, not the respiration, is paralyzed. Prevost and Battelli have made many observations upon death by electricity 2 and have found that animals in whom cardiac paralysis has been produced by low-tension electricity may be resuscitated by high-tension electricity. This was done in the case of a dog one electrode in the mouth, the other in the rectum. A o()-volt alternating current was applied for three seconds and produced heart fluttering, a condition of feeble and rapid action of the heart, which is the way in which electricity paralyzes the heart and from which spontaneous recovery seems to bo impossible. A few seconds later, however, the application of an alternating current of 4M)() volts tor two seconds caused a return to normal cardiac action, and the animal's life was saved. It does not seem a desirable experiment to try in the case of a human being, because of the probability of producing destructive lesions in the central nervous system from the passage of a current of such volume as the 4800-volt alternating current. Faradization of the pneumogastric nerve for brief periods is a means of applying a current of moderately high tension and of a quantity so small as not to be capable of producing pat hologic effects. h'tiniion f Rapid it 'i of Alternation to the Physiologic ami Pathologic EjTy Knkr. Stmttrart, HHW. " Coinptcs rendus de 1' Academic d's Sciences,'' vol. cxxviii, r\\x; ".Journal de Physiologic et de Pathologic irenerale," Is'.)'.), HUH); "Revue niedieale de h tfuisse Rnmande," 1X'M>, 1000. oti.S MKDICAL KI.KCTIUCITY AND Il(")\T(iKN KAY> effect upon living organisms. The highest voltages at this rate of alternation arc so dangerous that even an a|)]>r(>acli to the conductors should he effectively guarded again-t. ">.">() volts is often deadly and <*i to 11") volt- occasionallv so under exceptional circumstances. \lii-Miatiii- discharges are dangerous in proportion to frequency up tn l.'iil a second and become pn>o;ressively less effective physiologically bevond that frei|Uencv. A very much more rapid rat<- of alternation render- the same or even higher voltages hannless: and even deprives the current of it- propertv of producing sensation or muscular con- traction. Tesla, Thomson, d'Arsonval, and others have performed experiments in which high-frequency and high potential currents are passed through the body in suiiicient (juantity tu light a Hi-candle-power incandescent lamp requiring a current of \ ani]>ere under ordinary conditions. These g<> to show that alternations above ")()()() a second '. ise the ordinary effects of electric currents upon the living organism. And experiments by 1'n'vost and Hattelli with machines giving alterna- tion- all the way up to 1701) a second 1 show that the more rapid the rate of alternation, the higher is the voltage required to produce death or other pathologic results. Of course, ''high-frequency currents" are of a transcendental order of frequency, consisting perhaps of millions of o-cillat ion- a second, forming a to-and-fro discharge between the coatings of a condenser in the course of which their electric charges are liberated and iientralixed. This discharge and these oscillations do not take place directly through tin- patient's body, which forms only a shunt circuit for the discharge. The principal path afforded for the current in one tvpe of high-frequency apparatus is through the short thick wire solenoid. And the fact that any appreciable current passes through the patient in-icad of all goinii through the other much better con- ducting path i.- due to the development of an impeding self-inductance in the latter. iriirh-frequency currents in the usual strength and with a good with the electrode produce physiologic effects which are often |1 therapeutic utility. They do not produce pathologic changes in the I i>Hies. I h<-\ cannot be regarded as dangerous to handle, since bad effect i- ti'om -park.-. These cause quite a sharp sensation, ice the ordinary reflex muscular contraction by which nature In: b to be withdrawn trout anv source of irritation, fire and iui waiting for the sensation of pain to reach the brain pulse to be transmitted to the muscles of the limb. .' whiteness and .-welling of the skin followed by '-ring or ulceration of practically the nature of a burn upon one spot for too l^n^ ;t time. The shock which on accidental .Barking is trivial and the effects upon, ! -cribed are purely local, and require an application econds al a sinirle point. They are almost always a.- in de-t rovili'j cutaiieou.- uTo\vths. irrenl- applied as a shower of -parks produce, as n' 1 i -harp reflex mu.-cular contraction and marked ' ' ami i- true uhen the elect I'ode i- applied to a 1 . face of t he bod\ . The hi-h fre(juetic\- of -< fiL'un- in tin- uriginul articles in ' ' ' : I':l1 Imliii^ic." 1 Ml!). ELECTRO I'ATHOLOCY the alternations is, therefore, not the only element in causing an absence of sensation or muscular contraction in a human body, through which they pass when large 1 surfaces of contact are employed. Condenser Discharges and Their Pathologic Effects. Holeling a Ley den jar by the outer coating in one hand, and then touching 1 he knob connected with the inner coating with the other hand, one receives a spark and shock which is influenced bv the capacity of the Leyden jar and the voltage to which it is charged. A sharp muscular contraction of the arms is produced by such an experiment, but no pathologic changes. Experiments with larger condenser's have shown that small animals mav be killed by a single or by a small number of successive" single condenser discharges. Priestley, in 1 ?(>(>, killed dogs by the discharge- from a condenser with 6.5 square meters surface charged from a static machine, .cats with 3.5 square meters, and rats with ().(> square meter. Since that time various experiments and observations have been made bv Fontana, Troostwyk and Kragenhoff, Tourdes and Bertin, Richard- son, Laz/aretti and Albertoni, and by Dechambre. It is to be gathered from their observations that a sufficiently powerful discharge will kill small animals and that different lesions occur, such as ecchymosis of the pleura or edema of the lungs. D J Arson val made a report in ISSTMn a study of the cause of death from the industrial use of electricity To the effect that a static discharge could cause death only when applied directly to the medulla and very sharply localized. Prevost and Battelli- have reported a most elaborate series of experiments upon this subject. Figure 272 shows the arrangement of the apparatus, a 35-cm. Kuhin- korff coil being employed and a condenser of adjustable capacity. Fiji. 271'. I), Spintremeter; (', condenser; d, explosive distance; A, animal; S S, metal spheres 2 cm. in diameter, one of which is movable U'revost and Battelli). Kach plate of the condenser was of glass 2 mm. thick, covered on each side by 4S square decimeters (800 square inches) of tin-foil, and having an uncovered border of glass 11 cm. (4', inches) wide. There were 15 such plates, any number of which could he used as a single large con- denser, the capacity being 0.11) microfarad for each plate. The spintremeter or spark-gap (I)) of the Kuhmkorff coil is set at a greater distance 1 than the explosive distance* fd\ which deter- mines the voltage of the discharge to be sent through the- animal. 1 his is to prevent the discharge 1 from taking place' across the 1 1 "Comptes rendue dc l'Ac:i;\\ ing. The tjinint/t'i of electricity contained in a charged condenser or given out when the condenser is discharged is Q -TV. the capacity multiplied Voltaire ((' is expressed in microfarads, V in volts, and Q in t 111 n ici >uion;t>- d-ciar:_ r ie imrl: [>/ rfrninl in charging a condenser or performed by the irire of a condenser is W l('\" J or a number of joules equal to all the capacity in microfarads multiplied by the square of the joule 0.102 kilogram meter, or about O.S14 foot of Prevost and Battelli show that the effect of a in causing death or other injuries to animals is number of joules or to l('Y' J , not to the quantity Vi. i n trie -mall I.evden jar charged to a certain voltage -alne effect on an animal as a much larger Leyden ondenscr charged to the same voltage. The quan- i . 1 o2 microcoulombs ) in a condenser of 2. .'is micro- ed to a potential of 11,100 volts is greater than i niicrocoiilombs ) in a condenser of 0.17 microfarad ELECTROPATHOLOGY 371 capacity charged to 3300 volts potential. The energy or work (255 joules) in the smaller condenser charged to 33,000 volts is, on the, contrary, greater than the energy (154 joules) in the larger condenser charged to 11,400 volts. Provost and Battolli subjected a young rabbit weighing 1040 grams to a single discharge under the above conditions of small quantity (15,510 microcoulombs, but large energy 225 joules), and the symptoms produced wen; arrest of respiration, cardiac fibrillation, and death. Another young rabbit weighing 1020 grams was subjected to a single discharge under the other conditions of large quantity (27,132 microcoulombs) and small energy (155 joules), in which case breathing gradually commenced again and the animal survived. Fastening the animal upon an insulated table, one metal electrode was placed in the mouth and the other in the rectum. The polarity was found not to make any difference. The size of the animal determines the electric energi/ as a single con- denser discharge required to produce permanent arrest of respiration and death. The most powerful discharge from their 15-plate condenser (800 square inches in each of the two sets of metal coatings charged to a potential of 33,000 volts) failed to kill dogs weighing 6500, 7000, and 8500 grams (14.3, 15.4, and 18.7 pounds). The electric energy applied in the condenser discharges were cither 1029 or 947 joules, and the dogs exhibited no symptoms beyond slight temporary changes in blood- pressure. Rabbits weighing about 2000 grams (4.4 pounds) required 900 or 1000 joules to produce a fatal result. For instance, a single discharge from a condenser of 1.27 microfarads capacity, charged to a potential of 29,100 volts, and possessing, therefore, an energy of 549 joules, produced clonic convulsions, temporary impairment of respiration; the heart beat normally and the animal recovered. Another rabbit sub- jected to a single discharge from a condenser of 2.38 microfarads capacity charged to a potential of 29,100 volts, and possessing, therefore, an energy of 1029 joules, showed no convulsions, the heart beat feebly, respiration was abolished, and the animal died. Young rabbits weighing about 1200 grams required about 300 joules, and guinea-pigs weighing about 250 grams required about 130 joules, and those weighing 450 grams about 400 joules to arrest per- manently the respiration and kill the animal. Young animals in general are more susceptible than adult animals. Beyond a certain voltage represented by an explosive distance of about 1.5 cm. (/;-,- inch), more powerful results are better obtained bv increasing the size of the condenser and, therefore, its capacity rather than by increasing the potential or voltage as represented by the explosive distance. The effects of condenser discharges upon animals are proportional to the number of joules (the number of microcoulombs multiplied by the square of the number of volts), and inversely proportional to the size of the animal. A number of successive discharges will produce a cumulative effect, but not so great as the same total of electric energy in a single more powerful discharge. The pathologic 17 joules (from a condenser of 1.71 microfarad- rapacity. charu.ed to a potential of oo. ()()() volts), will survive two di-charge- of ~>\~ joule- from a condenser of (U)f) micro- farad rapacity charged to il'i.OOO volts' applied thirty seconds apart. Ann- the first discharge there were clonic convulsions: respiration and cardiac action \\eiv not arrested. After the second discharge there \\riv in i convulsion.-.: respiration continued: reflexes were absent, and there was urea! inhibition of all nervous functions. Recovery Took p!ar.- gradually. Several ditVereiil decrees of effect are recognized by Prevost and Matt 1. \ simile ire ne nil muscular contraction. _'. ('Ionic convulsions without much effect on res])iration, and rapid recovery. ;;. Tonic convulsions, momentary arrest ot thoracic respiration. 1. ( ieiieral inhiliii ii in of the nervous system, no convulsions, loss of reflexe.-: absolute arrest of thoracic respiration. The auricles of the heart arc often arrested. .">. Complete arrest of the heart: loss of excitability in the unst riped :i,u-cle of the intestine; preservation of the excitability of the striated 11 -cles and "f t he m< >li !' nerves. The hi ..... [-pressure varies according to the severity of the effect. In Prevost and Bat telli's first degree of effect the blood-] ressure becomes -liLrhtl; : after a momentary fall: in the second, third, and fourth ilrirre.-s it irenendly rises abruj>tly and remains elevated. In the third and fourth degrees there i.- sometimes a fall of blood-pressure, due to fibrillary tremor of the ventricle.-, which is temporary in these degrees. In rhe fifth decree the heart is unable to reestablish normal pulsations, i hi tibi illary tremor continue- cli aiming to complete arrest, and the fall in blood-pre.-.-urc i- [>ermanent. There is abolition of the excitability un-triped muscular fibers supplied by the sympathetic nerves. I he pathologic lesinns are slight, such as congestion with pulmonary dei a and -ubpleural ecchymoses. Rigor mortis is pronounced and Pathologic Effect of Alternating Currents.- Prevost and Kattelli, 1 ;il .I.L: the different effect- of alternating currents on dogs. cats. rabbit:-, and rats, found that the effect of these currents \\a.- tuiictjonal dissociation of its movement and -i"ii of fibrillary tremor. The same authors, .1 .!' death by ninii-nnnnti rnm-ntn, March L'7, 1S99, ithciently sti'oii.u current was applied, n dog was the he-art, fbnllarv tremor, while a guinea-pig i- "i respiration. The rabbit presents momen- ' t re m or of t he heart . and t hen a temporarv ree-tabli-hes itself ^raduallv. The maxi- ' In -e experiments wa.- .").")() volts. Alternat iim' '

    eri- ainl Hattelli (dogs, rabbits, L r ninea-])igs. and n.pt oiiis. The respira! ii >n was onl\- tem- 1 \\ ' ' .' ol general sen.-< iry c< indit ii ms. :, h r-1 fodi placed on t he head produces a t hoi ' .- , n-h i.- often t'olli iwei 1 1 iv chn inic -i . March, .,. IMi'.t. convulsions. When neither of the electrodes is placed on the head, it requires at least (>() volts. When the electrodes are applied to the anterior limbs, t he ventricles of the heart present fibrillary tremor, while the auricles continue to beat. This is the same result that is obtained by direct electrization with an induced current. This is always fatal in dogs, as the heart does not seem to be able to resume it.- normal function. The same is true of adult guinea-pigs, weighing at least 400 grams. The rabbit hardly ever dies, because the heart, most frequently resumes its rhythm. The rat never dies, because the tremors cease as soon as the electrization is stopped. In dogs and guinea-pigs respiratory movements continue for a long time, in spite of the paralysis of the heart. In this case artificial respiration could not be of an\ service. To produce the fibrillary tremor of the heart requires a contact of at least a second with the electrodes placed upon the head and thighs, or even over the precordial region. Preliminary section of the pneumogastric nerves has no influence over the phenomena of fibrillary tremor of the ventricles. "Death by high-tension alternating currents from 1200 to 4SOO volts, applied to the head and feet, is not due to fibrillary tremor of the ventricles of the heart, as in the case of low-tension currents. They provoke in all the animals grave troubles of the central nervous system and arrest of respiration, loss of sensi- bility, profound prostration, generalized tetanus, loss of reflexes." Death is due to respiratory paralysis, the arterial tension undergoing considerable elevation, and the ventricles beating rapidly and energet- ically, while the auricles are arrested in diastole. If the respiratory paralysis is permanent, the heart gradually fails. Currents of medium voltage, 240 to fiOO volts, applied to the head and feet, produce in the rat, the guinea-pig, and the rabbit nervous troubles, but less grave than those produced with a current of high tension. The heart does not present fibrillary tremor except in the rabbit. In the dog. however, fibrillary tremor occurs and death ensues from simultaneous cardiac and respiratory paralysis. Death from the Action of Continuous Electric Currents. The electrodes are placed one in the mouth and the other in the rectum or upon the thighs. The positive electrode is most often placed in the mouth, but the polarity does not make any difference. The symptoms the same whether the current is produced by dynamos or by eries. Dogs die from paralysis of the heart with a voltage of i 50 to 70. at the least, while respiration continues for several longer. The ventricles present fibrillary tremors while the auricles continue to beat. It was consequently useless to practise artificial respiration. With the highest voltages employed. 550 volts. th" heart was arrested by a single -hock, opening and closing of the circuit. Respiration was suspended for several seconds and then recommenced, but feehlv and slowlv tailed. In guinea-pigs fibrillary tremor of the heart was produced bv a ten-ion of 100 volts, but the MKDICAL KI.KlTKU Tl'Y AND HOXTCKX HAYS higher the voltage, the more pronounced are the. effects upon the nervous system, except in the case of convulsions, which are produced when the voltage is about 50. and do not occur when the potential is raised to 550 volts, and the duration of contact prolonged for two or three second-, for example. D'Arsonval. having stated 1 that the only danger from continuous currents lay in the shock occurring when the current was made and broken. Prevost and Battelli- made experiments to determine the facts. I'sing a direct dynamo current of 550 volts, and having a liquid rheostat of 15.OOO ohms resistance in series with the animal experimented upon, the current was turned on and off a number of times without effect of any kind upon the animal. The enormous resistance of the rheostat enable- one to turn the current ou and off without exciting muscular contraction c-r - in .y other symptom. After turning the current on, the resistance may be gradually diminished and the current increased to any desired strength without a "make" shock. It has been proved in this way that fibrillary tremor of the ventricles of the heart may be produced without any "make" shock. The gravity of the functional disturbances of the nervous system is also not appreciably modified bv the absence of the "make" shock. The Effect of the Presence or Absence of the " Break " Shock. Kibrillary tremor of the ventricles of the heart may occur without the "break" shock, and may continue and be the cause of death after the s'rvngth of the current is gradually reduced to zero by the rheostat, tin- occurrence of the "break" shock being entirely prevented. With 1"W-; elision currents, however, which are not strong enough to cause ary tremor without the "make" and "break" shocks, these tivrnors and the resulting cardiac paralysis and death may be produced by a break -hock. This would be done by turning off the current abruptly from its full strength instead of gradually reducing it by means of a rheostat. The " break " shock from a current of 80 volts or even 50 'Its applied in this way will kill a dog by fibrillary tremor of the Action of the Shocks of Opening and Closing the Circuit. LT!I enough tension, loo volt - in the case of guinea-pigs, neither 'mn:_ r nor closing shock is necessary in order' to produce fibrillary oi tin heart, but with comparatively low voltages, 70 volts, 'a-e n! dog.-, 'he heart continue- to beat during the passage of the fibrillary uvmor is produced by the shock of lit. With current- of hi<:h tension, 450 to 550 volts, which had been in a state of fibrillary the current are cau-ed to recommence "k ot breaking the current, but if one reducing the strength of the current remains permanent. In the dog, on the f breaking the current does not reestablish the i I'revosl and Battelli regard it as probable 550-vo|l current was not sufficient to pro- icks ot making and breaking do not appear influence upon the occurrence of troubles of 1 ' !' : " Vfn.1 -!-. Scicrifcs. April t. ]ss7. -.1 :. : i>- I'ntholotfif t-t .If ['hv-iolomf, IVJ'J. ELECTROPATHOLOGY 375 the nervous centers, hut in ruse, of u current of low tension, the condi- tion of generalized tetanus is provoked by the shock of breaking the current. Absence of Pathologic Effects from Leyden Jar and Other Con- denser Discharges hi the use of Electrotherapeutic Apparatus. The condensers used in high-frequency apparatus in connection either with a static machine, or an induction coil, or an alternating current transformer (D'Arsonval-Gaiffe apparatus) are of small size compared with those found necessary to produce pathologic, results in animals, and their effect is still further reduced by the greater size of men. Only the smallest animals are seriously affected by powerful condenser discharges. The single muscular contraction with slight increase in blood-pressure, which are the effects produced upon men by the discharge of any of the condensers used in electrotherapy, can hardly be regarded as pathologic. There is no danger of serious results in handling this part of the apparatus. History of Death from Electricity. Grange 1 was the first to report two deaths from dynamo currents. He also experimented upon animals, and considered that minute hemorrhages in the medulla caused respira- tory paralysis and death. D'Arsonval's article in 1887 was largely theoretic. He stated that the discharge from a static machine acted as a local disruptive agent and permanently destroyed the tissues affected by it. This would be the case also with lightning-stroke. Dynamo currents, he thought, acted in a reflex inhibitory manner upon the nervous ('(niters, and this inhibition might be received from them. Death would be attributed to respiratory paralysis, and the proper treatment would be artificial respiration. This will be found to correspond very closely with the most recent knowledge of the subject. Brown, Kennelly. and Peterson 2 reported experiments upon one horse, two calves, and a number of dogs. Copper wire wrapped with wet cotton was wound around one fore leg and the opposite hind leg of the animal. An alternating current of 160 to 800 volts turned on for a second always caused instant death. A continuous current of the same strength and for the same length of time was not always fatal. The usual number of alternations was 34 a second, and if this was increased to 100 or 134 periods a second, death was caused by a current of lower voltage. Tatum 3 reported experiments upon animals in which death was caused by respiratory paralysis. This occurred even when a pre- liminary section of the vagus had been performed, and also in atro- pinized animals. Electrocution was adopted in New York State in 1890. An alter- nating current of 1500 volts and from 15 to 30 periods a second is used. Several seconds' contact abolishes all sensibility, but the heart continues to beat and respiration will reestablish itself unless one or two more additional shocks are given. McDonald 4 reports the result of autopsies upon several persons who 1 Annalrs d'hyjiicnc ct do medicine Icgale, 1885, pp. 53 and 303. N. V. Mod. "Jour., 18X9. 3 Ibid., 1X90. 4 Ibid., May 14, Is92. iiTli MKhK'AI. KLK< rHH I TV AND KOXTGKN HAYS had been electrocuted. ( ':i|tillary hemorrhages were found in the floor ti f the fourth ventricle and in the third ventricle, hut they were not ci m-t ant . liiraud'- made three experiment- on rahhits with an alternating current of L'.'tiMI volts. It took twelve seconds to stop the heating of tin- heart . Philip Don lii r' believed that the current produced an alteration in the hlood which caused secondary change- in the nervous system. llattelli -tales that these change- in the hlood have not heen confirmed i >\ any > >t her ol server. ; Kratter experimented upon numerous animal- of different species, u-iim an alternating current. He concluded that death was due to paralvsis nf the respiralorv center, the heart's action failing gradually. Diifi rent animals vary in suscept ihility. (iuinea-pigs and rahhits are |e-- -iiscepi an dogs. 1 Fe suhmit ted rats to a current of 100 volts, . i. . required thirty seconds' contact to kill them. All the other ils were -uhjected to currents of higher tension. He did not find any con-tant lf-i<>n-. either irross or microscopic, the hloid and the cells ui' i he nervous system were unchanged. i > iver :ind Rolan 4 experimented upon dogs and rahhits with currents nf _'i H i volts. There was immediate arrest of the heart, while respiration continued until it gradually failed. They thought that the effect upon the heart was n dired one. as it occurred just the same when the pneumo- - d;\'ided. The electrodes employed were moistened sponges which were applied to the front and hind legs, which had previously heen shaved. They tried to re-animate the paralyzed heart by various met hod>. hut unsuccessfully. ( 'orradi/ applied continuoii.- currents of hiirh tension to dogs. The animal- died immediately, even from very >hort contacts, and both heart and respiration -eemed to he instantly paralyzed. All the above oh-ervat ions are quoted more or less in extenso in I': vo-t and I'at telli's excellent monograph upon Death by Electricity.) Ha'telii ha- made the experimental study upon which most of our knowledge lit the -uhject i- ha-ed. The < It ctriidi s for application 'i t h-- -km were made ot copper or /inc. covered with moistened cotton. 1 d a ml the electrode bandaged in place. The mouth eleet] |e-, foi dou-, coii.-isteil of two copper plate- placed in the fold e L r um- a nd t he cheek. llectal elect rodes were made of brass. "nee ni cun'ent wa> the alternat ing elect ric-lighl circuit, the -In Volt.- difference in potential bet \\een the if the other-. Thi- current was niodilied \t\ a . L r i\ in- \ oltaiie> of dill I. I'JIII). ISOO. - Ml !. I'tier-e figure- I'epi'e.-etit t lie effect ive \'o|t age, wllicll ' irmula hi-iii- i rue of sinusoidal I " i-i . rt'eni ill .' -- i iia ii I '_'( ) \~olt s, a s] piral ' ; '' "i H i ohm- - mi roducei 1 im o t he circuit , and I !-'< nl' N \\ Y"rk, NI i\ i in! M r 1 1 1. 1 ss'j. ' I i rt I'iril : ' . !.' ;./,-. I v. H, i |.-,. Is; ix -. , . !-' : :,. N., ;:,. I' . ,i I ,,.,, . |sl'.|. KLKCTKOPATHOLOGY '.$~~ any (wo turns arc connected with the electrodes. Klectric measure- ments are made (luring the experiment l>y means of the voltmetei. the amperemetor, or milliamperemeter, and Kohlrausch's telephonic bridge to measure the resistance of the body. Sometimes the contact was as short as one-twentieth of a second, and then the amperemeter or milliamperemeter would not register; but the strength of the current could be calculated from the voltage and the electric resistance of (lie animal's body. Destructive Electrolysis. An electrolytic needle thrust into an organ like the kidney, testis, or brain destroys the microscopic structure of the organ. Pathologic Effect of Electricity Upon the Blood.- I'nder the influence of a powerful electric current Hollet has observed a dissolving out of the hemoglobin in the red blood-cells, the blood becoming transparent and consisting of a clear red liquid in which are suspended colorless and perfectly transparent blood-cells. This has been questioned by Herman and (Yenier, and must still be considered as unsettled. Accidents from Electric-lighting and Power Currents.- Fatal acci- dents have 1 occurred with alternating currents of as low as 100 volts. As to the amount of these currents passing through the body, abso- lute safety requires that it should not exceed 25 ma.; 30 ma. is often dangerous, and 100 ma. is almost always fatal. The resistance of the human body to the direct current is about 50, 000 ohms when a bare wire is touched by a finger-tip, and GOO ohms when a conductor is held in the hand. The same figures are 15,000 ohms and 200 ohms for the alternating current. Kubber gloves are a most uncertain protection.' A case of accident from contact with a live wire is recorded by X. Jacobson.'-' The patient was a boy twelve years old who took hold of a bare wire carrying a current of (5000 volts and !H) amperes with his left hand, while it is supposed that his left foot touched the companion wire, so that the current was short circuited through his body. There was not exactly a burn, but t here ensued an impairment of arterial supply, either from thrombosis or vasomotor contraction, and moist gangrene set in. The arm and leg had to be amputated fifteen days after the injury. There were no special symptoms of constitutional or visceral disturbance, and the bov recovered. The wires were carrying a current of four times as many volts, and from fifteen to forty-five tunes as inanv amperes, as are required tor the electrocution of criminals. There is tin'.- great difference, however, that in t he case of t he criminal care is I a ken to make a large and perfect contact between the shaved and moistened skin ot the person and uimxidizcd surfaces of the metallic conductors, while in this accidental case i he wire was exposed to the weather and its surface presumably oxidized and a poor conductor. The area ot contact when a wire is grasped by a boy's hand i.- small, and when >imply touched by a boy's foot, is still smaller. Add to this the resistance of the boy's shoe and stocking and the possibilitv that his foot did not come in contact with the wire, but was nierelv grounded, and it is easv to see that the ;I7S MKDICAL KLKCTHK ITY AND HONTCKN HAYS iv-i-tance was so great that a ten-ion of (ifiOO would send a very much weaker current through the 1 toy's body than the 90 amperes which it -end< through the complete system of conducting wires to which it is designed to supply current . l'ases treated by the present author include one in which a telegraph lineman was injured by grasping a telegraph wire which had become chained with the ">(M)-voll trolley current. This happened in midair. and as he hum: there unconscious the wire burned deeply into the palm of the hand. After a few minutes lie fell to the ground and fractured hi- femur. He made a good recovery. Another case was that of a man injured while working upon the charged wire in the slot of the buried trolley wire. Then- had been a blinding flash as his hand i'.uched 'he wire, and the skin of the hand and wrist was singed and h . Hi d. There was a marked reduction in motor power in the hand, and t hi.- took Imitrer to cure than the burn. Burns in Electrotherapy. The burn which may be inflicted by the ti'iw of M current of _>() nia. for four seconds, as may happen if too strong a current i- used in Fort's method of linear electrolysis, is cer- tainly not \ Laurel and Belloeq all electrode moistened with a 1 : 1000 i] it ion ui caustic potash produced a burning sensation upon the operator's Ion-arm which could hardly be borne with a current of . applied for two or three seconds. A calculation show.- that only milligram "t pota.-h was set free, not enough in an ordinary chenuc '. ! to produce any perceptible effect upon the skin. The effect 1 solutions employed and the exact arrangement. Some " ' "t her experiments upon t heir own forearms were as follows: ( ".' led rode con.-ists of a lit t le glass cylinder, open top and bot torn, Men applied to the skill, can be filled with a liquid. The i" i! ' " in ued by t he pat lent '.- skin, and a wire passes into the liquid :' I he top. Another electrode consists of a porous II nl liquid into which a wire dips and the bottom of indifferent positive pole at upper part of t n>de ui ordinary size covered with moist or Ml ma. was required to produce the ve. L* ever.- in ^ t he cu rrent , 20 ma. were ELECTUOPATHOLOGY 379 of sulphuric acid was used as the active electrode, and the same burning required only 2 ma. Fourth Experiment. The glass cylinder full of To Yoth these characteristics tend to : ... . nt chaiiire- iii the .-kin as the result of comact with the metal. It a l-i i make- I in le difference what metal is cm ployed. Metallic electrode-; mav also lie used for the application of static electricity and hiirh-freqnency current- of either hiirh or low potential. The -mall amperaire in the tir.-t case and the alternating character of : : ; ,- di.-diai'ire in the case of hitrh-frequency currents prevent electrolytic effi-d. I'royidini: tin- electrode is in irood contact and is of sufficient -:,/,. no effect i- produced upon t he skin at t he place oi con t act . 1 he conditions are quite different when the iralvanic current is used, and e-pedallv \vhen strong applications of it are mad*-. The current tinuou- and unidirectional, and has the strongest tendency to i- elect roivt ic effects in t he t issues, even wit h plat inum elect rodes. .: ich undergo practically no chanjre ihemselves. Additional changes are ppiducerj when copper, iron, or oilier corrodilde metals are used as Tl,, />-".. ,,<< in I'ftfrrttitil Hitn-tni flu Eticlrndt- tntd the Skin. The i ic i pie- lor ? he preveni imi of t hese dia litres, known collectively n.~. an In ciirrenl density must not lie toojrreat, perhap.- ire than 1 1 a. per square cm., am 1 that the difference in pot en - 1 iei veon t hi -kin and t he elect n le must not he 1 oo irreat . I f t he I'ence in potential i- too li'i'eat, diaiiires a re produced in the skin ii ' ,o sample-; Iroin ordinary phy-n-al processes may hi ."'' ::rj there i- a difference in [iiitelltial lie! ween - of. -av. I l'i vo|t-. and if these wire- are allowed to touch - a Mindimr fla.-h. and the metal is melted, vapor- ' e|-e i~ al-i . t he d a ii'jer o| set I ill ^ f I re to the I iu ill 1 mir. "ii 1 ' . Hit il I he current i- I timed i iff. |>erha ps ailP unat- i'll o| a |'u-e. ( 'out rast I his with the effect :; re \'. ires connected wit Ii t he poles of a ' ':' ri fore, ha -, mi' a difference of only I ,",;"',-,- \"ol is \s h<-n t he cont act i.- I D-< iken. I ut no 1 ' all; toiii >t her and t he difference i t o /' I he t v i u ire ha \'e a d il'f< 'fence in t n it ent ial 11 cunt aci . m;;de v, n h the liquid, and a differ- II e- el when 1 he elect Hide- an illl Iliersed. ' " ' '.' ii ' lirl I lie liquid t 1 hi p ' of t he ciirrenl 1 ' to t he liquid i- accompanied I,-,- vapori/at ion ELECTRODKS .381 and incandescence of the liquid, so as to form a luminous sphere around the platinum point, and momentarily break the contact with the liquid and interrupt the flow of the current. The effect in the Wehnelt interrupter is never exactly duplicated in the application of currents of the proper intensity for therapeutic use. The flesh is never vaporized and ignited, but when heavy thera- peutic currents are used, contact with a small metallic electrode will produce electrolytic effects, causing pain and perhaps even blistering or dest ruct ion of the skin. Such effects are obviated to a great extent by having the current enter the body through the intermediary of some substance having about the same resistance as the body. 'There is then onlv a slight difference in potential between the skin and the substance in contact with it. A sponge wet with a solution of sodium bicarbonate may be used to cover the surface of a metal disk connected with one pole of the battery (Fig. 273). The patient's body and the solutie-n then form a continuous electrolyte, and the changes due to electrolysis take place practically entirely at the surface of contact between the metal and the solution of sodium bicarbonate. It is then' that there is a great increase in the resistance encountered by the current, and it is there that the electromotive force of the battery maintains a great difference Fiji. 27'5. Sponge electrode and insulated handle. in potential. The effect of electrolysis at that point is seen in the corrosion of the metal and in a dissociation which ehemic analysis would show to have occurred in the solution. All the different electrodes for external use. covered with moistened sponge, felt, chamois skin, cloth, clay or kaolin, are based upon this principle. They all possess another advantage over metal electrodes for external use in the fact that the moistened material makes a much larger surface of contact with all the interstices of the skin. The current is supposed to be largely transmitted through the sweat-glands, most of the other parts of the skin being highly resistant to the passage of a current. Cases occur, however, in which the effect of the direct external application of a metallic electrode 1 is desired. The treatment of ulcers hv zinc iom/ation is an example. The active positive electrode is of /.inc. and is applied directly to the ulcerated surface, and the caustic effect of t he liberal ed /me ions is beneficial in some cases. Cl/iil Klcctro<{rx. Ordinary modeling clay in a moist soft condition may be used to secure a uniform resistance at all points ot contact with the skin, and, what is equally important . a contact without too u'reat a difference in potent ial. The clay is shaped into a disk of the proper si/e, and about I inch MKD1CAL l.l.i:i rHK 11 V AM) KOVK.KN KAYS thick, and a sheet of metal about -. This material, from which some kinds of porce- lain are made, should he purchased in powdered form, and sewed up in flat hairs of crash toweling, so as to make a pad 1 inch thick, and of different sixes, such as x hy 12 inches and 14 hy 20 inches. The latter are for the indifferent electrode; when the heaviest currents are used. The kaolin pad- are kept in water, and may IK: sterilized hy boiling if they are to he used more than once. The largest sized pad will transmit a current of .">(>( I ma. without burning if plaeed under the patient's hack. A piece of flexihle sheet metal, of the kind known as x-ray foil, 2 inches less in each diameter, is laid smoothly over the side of the pad away from the patient. A Xo. 20 insulated copper wire from one pole of the hattery or other electric generator has its end bared and passed through perforations in one corner of the sheet metal, which is then wrapped around and securely pinched to the wire. It. is wise to' put a piece i,f rubber-coated cloth between the bared wire and the kaolin pad. /\'i"//fi junls of suitable sizes and sha|>es are also useful when a heavy i-urn-nt is to he passed through the knee-joint. Cnrhnii i licirnr/i .s covered with chamois and frequently rinsed in pure water to remove electrolytic products may he used on the delicate -km ' .f children. Electrodes for Application to Mucous Membranes. There are al reasons why these are usually made of metal. They are not required to transmit the verv heavv cur- '' - foi : L r e kaolin pads are useful. I hey ;ire used chiefly f.,r current s intended 'op duee a local effect , which varies in '''" '' ':;-.,.- Irorn a mere st imulat ion t . < .''n cau-tic action. The moisture upon the surface of ' ' olten take- the place ot the moistened Sponge or ''ma] applications in preventing electrolysis of ' ' ' however, only foj the weakest currents. A ' '< current of :> ma., and a small electrode p:dn and frothing from Caseous evolution ' '' o] ] oi' _' ma. Klectrolv.-i- of the tissues of ELECTRODES 383 a mucous membrane without the influence of ions from the metal elec- trode is obtained by the use of platinum electrodes. The influence of metallic ions is sometimes desired, as in treatment of fissure of the anus, where a copper positive electrode may be used. Bipolar Electrodes. These are sometimes used, especially in the uterus or urethra (Fig. 274). The two conducting cords from the battery pass to two metallic terminals in an insulated stern of hard rubber, through winch wires lead to two metal bands surrounding the stem. These have an insulated space of \ inch or more between them. The effect of the current is quite local, there being practically no general diffusion. Another form of bipolar electrode (Fig. 275) is suitable for external use. One terminal is a point in the middle of a ring which forms the other terminal. They are \ inch apart. Bipolar electrodes are also made for galvanopuncture. ELECTRODES FOR GALVANOPUNCTURE A fine needle of platinum or, preferably, iridoplatinum is held in an insulated handle as the negative electrode for the electrolytic destruction of superfluous hair (Fig. 276). A fine steel needle with some flexibility, like a dental broach, may be used for the same purpose, and if so, it is especially important that it should be connected with the negative wire, because of the iron staining of the tissues which would result if it were the positive electrode. Needle electrodes for the destruction of vascular and other nevi, and of tumors, and for the cure of aneurysms, often have an insulating coating of collodion or varnish to prevent action upon the skin and limit it to the deeper tissues surrounding the point of the needle. Galvanocautery Blades. These (Fig. 277) are not really electrodes, but rather parts of a complete circuit where the resistance to the flow of the current is so great that the conducting material become? red hot or white hot. Platinum is the usual material for this purpose, and a strip is used which is very thin and narrow when only a few galvanic cells are to he used, as in most operations on the nose and throat, but broad and heavy, though only so by comparison, when currents of 50 amperes or more are employed in such operations as Bottini's, upon the prostate gland. In some eases the platinum is wound about a porcelain point, giving an increased surface. Brush Electrodes. These are made of fine brass win 1 , and an 1 used for the application of faradic currents by nibbing the flexible brush lightly over the 1 surface 1 (Tig. 278). Roller Electrodes. Metallic cylinders may be rolled over the surface 1 in certain applications, particularly of galvanic and static electricity. The roller may be monopolar or bipolar (Figs. 279 and 280). Faradization by Rolling Electrode ("Badigeoner" of the French authors). The metal roller is covered with wet cloth, and as it passes :',x} \II:IH< AI. KI,K< TKKITY AND ROXTOEX HAYS nver the motor points causes muscular contraction. It is for thera- peutic u-e rather than for examination. Glass Vacuum Electrodes. These arc made the subject of special paragraphs at p. I'.' 1 .'. Condenser Electrodes. The-e ;d.-o are ,-pecially considered (p. 49S). Electrode Handles. The.-e h;ive ;m in-ulateil m'i of wood or KLKCTKODKS iii; electrode handle (Fig. 281 ), or an insulated section may intervene, and the electric connection between the conducting cord and the electrode may be made and broken by a Morse key, which form.- part of the handle' (Fig. 281?) . Intragastric Electrodes. These are metallic electrodes with an insulated stem which may be so flexible that the patient is required Fin. 27 ( .K Monopolar faradic roller dec- Fig- 'JsO. Bipolar faradic roller electrode trode. to swallow the electrode (Kinhorn), or so stiff that it may be used t< push the electrode into the stomach (Boas), or there may be a flexibl< Fi<^. 2!->l. Xon-interrupting handle fur electrodes. insulated stem and an additional stiffer one used for introducing tin electrode, but removed later. 1 Fig. L'SL*. Interrupting handle for dootr In everv case the metallic electrodes should be protected from direct contact with the tiastric mucous membrane bv being enclosed m a icrforated shell of hard rubber. 1 Rasslor, Jour. Am. Med. Assoc., Mav J. l'.)S. ELECTRODIAGNOSIS THIS ft insists chiefly in determinin<: the effect of electric stimulation nf nerves ami muscles, and of some special orirans, and in determining the elect ric resistance c,f the body. The Electrodes. The active one has a surface of .'> square cen- timeter-, and is usuallv applied at the motor point of the muscle or nerve. 'The "ther elect rude is larger and is usually applied at some indifferent part of the body. They are both thoroughly \vet with a .11 of -odium chlorid or of -odium bicarbonate. Normal Electric Reactions. The faradic excitability is more or le-- empirically determined l.y comparison with the similar adjustment the apparatus to produce muscular contraction in persons whose |es and nerves are in a normal condition. The galvanic excitability should lie such that in most regions with tin active electrode applied at the motor point of a muscle contraction takes place at the cathodal closure with ', to 1 ma.: at the anodal closure, with 1 to 12 ma.: at the anodal opening, with 12 to 12'- ma.; and at t In- anodal closure, with 1 "> ma. The amplitude of t hese different contractions with the same strength of current is expressed by the A .. -//Kit fur in /lid .' ('a Cl (' An Cl (' An () C ('a (>('. Tiie radial nerve and sometimes the median and peroneal pve a .. different normal formula, Cad (' An ()(' AnCiC CaOC.) /' ''/ : 7'' - Lnn's.- 11 i uk <~iirroi 1 vcymond's law paii'e :>:'> \ < and the table of lal n act ions pain- !JI1 1 i. M"' I'oin',. The illustrations (Plates I si -how the positions ictive electrode -hoiild !>, placed in order to produce t he >-' i-tt'-ctivf stimulation of the muscle or motor nerve in question. . Castex. and Schatxki. i p 'ii persi inal i ihservat ion-. \l\n I',, inf. . The ' ml: <>f '/ . f,n-!ul in rrt may be . b'. mean- '.i a -mall elect rode in t he e\t eriial audit ( >ry meat us il ml ijiwa rd. , ' be stimulated unh a very small electrode 'rior b'-rdcr o! the -ternomastoid muscle. It pro- ' p it ii in. v.'it h p!'> it ru-ion o| i he abdomen and a t h rou L r h l ' '.' - ' ' culai fo->a ;ind i 1 - -t imulat ion .'' ' ' ':- '' ; ' ' '' i'-n o| he deltoid. : ic> |i- . brachialis r:.ay In t i he bend of the '., i ,.,-i tin He. \ i, r tendons. Electric Resistance of the Body. l ; i- trcnerally a little lu'^her PL. ATI: I H.A I'H /. .. PI. A 1 I: 4 PLATH 5 M. rvtrahens aurem PLATE 7 * .4g5 M . _ KLKCTROD1AGNUSIS 387 in women than in men, being about 1400 or 1500 ohms from one hand to the other in women, and 1200 or 1300 in men. This is with hands cleansed by washing with soup and water, and plunged in glasses con- taining salt solution at the temperature of the body. Holding two dry metal electrodes in the hands, a resistance as high as 100,000 ohms may be found in consequence of dryness or greasiness of the skin, and it would vary with the firmness with which the electrodes were held. Increasing the strength of the current reduces the resistance of the body. In experiments by Weiss the current was at first 5 ma. and the resistance 1570 ohms; increasing the current to 10 ma. lowered the resistance to 1350 ohms; a still further increase to 23 ma. lowered the resistance to 1 HiO ohms; then a reduction to 10 ma. raised the resistance to 1200 ohms; and a final reduction to ma. raised the resistance to 1340 ohms. These figures are partly attributable to the effect of the passage of a direct current in reducing the resistance of the body, for the resist- ances toward the end of the experiment were less than at first with the same strength of current. Leduc 1 does not find that moistening the skin or dilating or con- tracting its blood-vessels by means of heat or cold has much effect upon the resistance, but the profound anemia produced by adre- nalin decidedly reduces the resistance of the skin. The nature of ions and their degree of saturation as produced by the amperage and the voltage of the current do, as a rule, produce variations in the resistance. Relation Between the Area of the Electrode* mid the Electric Hcxixtance of the Bod if. The area of the surface of contact has quite a decided effect upon the electric resistance. With the electrode moistened with a solution of sodium chlorid and the skin already saturated with these ions, a uniform electromotive force of 6 volts produces the following num- ber of milliamperes of current with different areas of contact. With a surface of 2 square centimeters the quantity was 2 T f )f , ma. Surface. 40 centimeters Milliani] >eres. .'it i 4 .SO 4 .60 ,, s 4 43 24 4 >5 4 07 in ;^ 7'' x ;> 55 7 :; .30 2/>X 2.0.') These figures correspond to a resistance varying from 1200 ohms to 2400 ohms, depending upon the sixe of the surface of contact. Laws of Stimulation of Nerves. DuBais-Re^mo-nd's / the variations which occur in the strength of the current in a certain tune. Q bt. 1 Arch. d'Klectririte inr.l.. .lune '_'.">. It05. 11,1,, r,,; ,u, 'i M "a-ed upon the theory that the -trench of the current is i he important factor, hut that there is a certain variation ~- iinulai ion produced by \ he make and break of a i:a lvalue current accord inn to the rapiditv with \\i.ieh the actual make and break are ipll-hed. With M current of very slmrt duration, such as an isolated induction di-chartri- or t he discharue of a comleliser of small capacity. the time . ,~:it may lie disregarded in \Yeis.-'s formula. (> is the (|Uantity of iciiy necessary to produce stimulation. 'I'he value of li is prac- iperaire of the weake.-t galvanic current which will lee muscular conn-actions when instantaneously made or closed. 1 , bv means of a condenser of known capacity, ('. charged to different . _.- and ' ii-ciiar^ed. we determine the voltage, \. necessary to proilm-e contraction. The \-olta<:'e ivijuired with the galvanic curi'ent < liv id. ; ',' the aiu]tera.re ^ives the resistance H iii the circuit. H "" ' '''/' form iln f'<>i' xttnitilutitin />'j cmidcuxcr dixchurycs'. I:. is expression \" is the volta.ire to which the condenser of a ' . i ' must he charged, and '/ and ,' are coefficients. Clu/ei find- that ()/_' inicrocoulonib discharged in a very short time . ' : ii\ what mean-) pi - oduce> contraction m a normal muscle. o-excitahility. To oltserve -iir^le contractions from isolated induct ion shocks turn h < ' . -ci-ew of the farad ir interrupter until it will no longer vihrate. e - sinule contact h\- pressing it \\ith the tiimei'-tip. M i-ielo hi'come wa-ted when paraly/ed hy organic disease of the [o-.vr inotiir -eminent 'aiitei'ior cornua of the cord, motor nuclei at the !ia~e it; the hrain. neuritis i nerve injui'y). l-'aradic excitability iced iir i- just liecause tins torm of electricity can produce :.';-] oniractinu practically only throu.tih stimulation of ner\'e- Application of Condenser Discharges for Electrodiagnosis. :ii'L r e is of such -hurt duration that the resistance of not have time materiallv to change. It i> unidirectional. cMcally tree trom eject i'ri]\-sis. These facts make it ' .':!!- o! diagnosis than t lie L r a! vanic curi'ent U in lei' cert a ill f 'oiiden-er- of capacities of frmu (1.01 to '2 microfarad-, or a divi>ihle ' are required, and a!-o a galvanic battery of '.'>(\ to o( I cells. ' -in elect ric-lij_rj]i current may lie used. In the '' cniiden-er ha- one armature grounded and ' '''! wilji a -witch or Mnr>e key, 1\ \-"\u. ^.Siv, 1 ,y - connected eitJier \\llii one p.ilr ,,f the batter\- HI ej, tn.di applied to the patient. The ,tlier p ( ,l,. ,,f the I lie other ejf-el rode applied to t lie patient is A cell -elector enable- one to connect any de-ired i >r. if -nine other xnirce of electricity i< - required. And a voltineler connect inu' the "' ' "' ' niea-ure- tJie potential to wliicji 1 he condenser KLK( TKODI.Ui.NOSjIS 389 is ch;ir, depending upon the motor point to which the con- The value of is from 2 to denser discharge is applied. It is reduced to O.'Jo or even 0.07 in trau- matic paralysis, and to 0.0006 in complete degeneration of the nerve. The intensity of the galvanic current required to produce a minimal cathodal closure contraction is measured in milliamperes. Then- is a certain normal relation between this intensity / and the condenser excitability, which is expressed by the formula charged by connecting the two poles of the battery with the two arma- tures of t he condenser. Turning the switch the other way disconnects the battery from the condense! 1 and connects the two armatures of the latter with the patient. \<> t:r<>und connections are required wnh this li'.K) MKDICAL KLKCTKIC1TV AM) KONTCiKN HAYS arrangement. The double-pole switch may bo a hand OIK' for single dis- charges, or it may be of the pendulum type, making contact with a cup of mercury and giving discharges at intervals whose frequency is ad- justable. In the latter case a separate battery of about three cells is usually required to operate the switch. Damp sponge or chamois- covered electrodes are used, the active out' being !> cm. (about 1 inch) square, and the indifferent one measuring ~> X 10 cm. (about 2X4 inches!. The voltage normally required to produce a contraction from con- denser stimulation of the median nerve varies in adult- and la rue chil- dren, and under different com lit ions, bet ween 14 and JO volts. In young children :->0 volts are required, and in tetanus only 7 or S volts. Repeated condenser discharges markedly increase excitability, so that a -mailer voltage will produce contraction. Faradization, on the other hand. e\hau-t- the excitability, and -trongcr currents are required after it ha- been u-ed tor a time. With a eL'irLMtm potential of UK) volts and the re-i-tanco of 1000 ohm-, -hown bv the bodv with ordinary wet exploring electrodes and conden-er- . llijpo-excitabilitii and Sl/ii/i/ixJi Contractions. Degeneration is not always complete, and does not always produce even inversion of the formula. Sometimes hypo-excitability and sluggish contractions are the only symptoms upon which the elect rodiagnosis of motor nerve degenerat ion is ba-ed. I nt( ///< tat/on i if tl/i h'< art/on til Uujtin ration a* l)<'*cntn'({ I title/' JIta

  • . Thi> never occurs in paralysis from a cerehraljesion or from a lesion of the spinal cord which does not involve the anterior cornua. Il is -trictlv a svmptoni of injurv to the motor nerve and the tranirlion-cells in i he antei'ior cornua from wliich it springs. It is found m infantile paralysis (anterior poliomx eht is), acute poliomyelitis m adult-, diffuse myelitis involvum the anterior cornua. hematomyelia, traumatic and toxic neuritis, rheumatic and mlective paralysis, and m the Aral) Muchenne type of myelopathy. Charcot's disease, syringo- myeha. and amyotrophic lateral sclerosis. ; ind m accidental division or surgical resection of a motor nerve, or paralysis from involvement in bony callus. The reaction of degenerat ion does not appear in some 1 slow cases of spinal muscular atrophy. There is only a gradual loss of i:al vanic excit al>ilil y. E j'ii m /nation for tin h't action of /)<ld i he positive electrode at some indifferent point and place the negative electrode at the motor point of the muscle. This active electrode should have a small surface, not more than ', inch in diameter, and should he applied with a uniform pressure of about 11 pounds. Thi- pres-ure -liould not vary while the current is being made and lro :en. The author's diagnostic electrode is designed to oveicome the : 11 ' - which are present in elect rodes where 1 he current is t urned on and off hv the pressure of the same hand that holds the electrode, and hv uncertainty as to the amount of pressure exerted even when this is not the case. Starting from zero, the galvanic current is irraduallv increased in st renirt h, while the current is repeatedly made and broken unt il a closure contraction takes place. The pole-changer is then reversed, connecting the exploring electrode with the positive and the indifferent electrode with the negative pole. The position of neither electrode is changed, nor is the pressure upon the electrode or the rheostat controlling the -trem_ r th ot th' 1 current changed. It a closure contraction no longer occiu's. , ,[ it' n is much wea ker than was the negative closure con t faction, there i- MO reaction of degeneration, hut if the positive closure con- ft iin eipials or exceeds the contraction obtained when the exploring I'li'i-T i-iiilc was connected \\'ith the negative pole, then reaction of de- [ireseut. 1 ' ',' i-riiit ract ion of the particular muscle under examination is ' ' i i ':>:. - ' !<'. 1 . not aliv 'j.< !HT:I] motion of the limit. Slo -<[ i-ont r;ict ions are the most important features of de- otni'tiines ihi 1 only chaniic In be discovered. ( i. / '" /,'''''' n of f 'nni fn'i xxi i ni. 11 us i> somet lines lou nd after a liml) n-'ed ir. ;iti I'.sniarch band. I here is normal or increased ' ibility, wiih L r al\'amc h\'pefe\cit abilit y, and a cliaiiu'e in I 'a' M ' much st n im;ei t ha M Usual. ' 'a( '!' ' An( 'K ' ('in \ i n 7 / p //''" i't' f-'a'iii'ii . lh is means t ha I repeated c( nt ract ions >! and -'rotifer currents to produce them. It is on]\- -u. -h ,iise,-|s,.s as paralysis of cerebral origin, hemi- .- . -<-iat i' - a. proLi!essi\e mii.-cular at ropli\ . anterior KLKCTRODIAONOSIS 8. r fhc Myotonic Reaction. This occurs only in Thoinscn's disease. It consists in faradic and galvanic hyperexcitability for both the nerve and the muscle, and in a marked change in the form of the contraction. The galvanic cathodal and anodal closure contractions are nearly equal, and are tonic and prolonged. Anodal or cathodal closure tetanus may occur with currents of /> to 10 milliampercs. and sometimes anodal opening tetanus. Completely tetanizing faradic currents cause tetanus which lasts a variable length of time after the cessation of the currents, and also undulatory contractions in neighboring muscles. The latter sometimes occur with the galvanic current also. The special phenome- non of myotonia or fusion of successive muscular contractions is elicited when the galvanic currents are made and broken at moderately short intervals and are of a strength which would produce only isolated mus- cular contractions in a condition of health. Repeated muscular con- tractions, either voluntary or electrically excited, gradually exhaust the property of myotonia. 9. The Antagonistic Reaction. This occurs in multiple neuritis, showing an increase in contraction under intermittrnt cathodal stim- ulation and a diminished contraction when the anode is the active electrode. Rich's Reaction. -When this is present, the cathodal closure con- traction and the cathodal opening contraction tend to become equal to the anodal opening contraction, whereas, normally, the latter requires about ten times as strong a current as the former. This reaction seems to indicate! insufficient blood-supply to the nerve, but it is not always possible to tell the exact cause of this condition. Remak and Doumer's Reaction. This is a condition in which the muscle contracts more readily to a current applied near its extremity or near its tendon than to one applied to its motor point. This reaction appears very promptly within one, two, or three days after the injury to the nerve and may be found in some cases which do not show Krb's react ion of degeneration. In the latter cases the wrong- diagnosis would be made if the examination at an early stage of the case were made by stimulation of the motor point alone, for the muscular response there may be as good as normally. In the case of a long-standing complete injury to a motor nerve all muscular contractility to stimulation at the motor point may be lost. and so Krb's reaction of degeneration could not be obtained. \o response taking place, it would be impossible to say whether or not there was inversion of the normal formula. In some cases, however, even a year or more after a completely paralyzing lesion of the nerve. Remak and Doumer's reaction may he obtained (contraction from the application to the extremity of a muscle of a current which will not produce a contrac- tion when applied to t he mot or point). Remak and Doumer's react ion is more marked at the anodal closure contraction than at the cathodal closure contraction. Electrodiagnosis in Eye Diseases. It has been known for a long time that the passage of ('lee trie currents t h rough the eye would occasion luminous sensations, and that the making and breaking of the current and changes in its intensity were especially productive of these sensa- tions. Several observers -Ritter. Purkinje. Burnham, Miiller. Benedict. Althaus, and La (irow. amonu' others have studied this effect. '1 he 394 MEDICAL ELECTRICITY AND RONTdEN KAYS color and shape of the luminous subjective image have varied so greatly under similar conditions that it is probable that they are different in different individuals. It is supposed that there is no direct connection between the strength of the current and the color and intensity of this luminous image. The luminosity is quite certainly not excited by electrification of the brain itself. Currents which pass between elec- trodes placed at the two sides of the head do not produce any sensation of liirht. although it has been proved that such currents, even if as weak as 1 niilliampere. do actually traverse the brain substance. Currents applied to the temples, however, do sometimes produce luminous sensation-, and it seems probable that these currents traverse the eye or the optic nerve in part. A long series of observations by different men has shown that the sensation of color and light is due chiefly to excite- ment of the retina, but partly also to t he excitement of the optic nerve. It will take place, for instance, after the eyeball has been removed. (See patre O.'M for experimental evidence that stimulation of the optic nerve does not produce sensations of light.) The strength of the cur- rent required to produce this visual sensation is very slight in the healthy eye. Placing the negative electrode upon the temple and the positive electrode upon the upper eyelid, a current of only -^ niilliampere. or sometimes only 1 1 U niilliampere. is sufficient to ex- cite a visual sensation in the eye. After removal of the eyeball, how- ever, a stronger current is required to produce the effect. In one case tested eisrht days after emicleation a current of 1 niilliampere was required; in another case one year after emicleation I/',, milliamperes were required, and in one case, five year? after emicleation. .'> milliamperes, and another, ten years after enucleatioii, 5 milliamperes. In the latter case, however, the perception of light was noticed in the sound eye; evidently the current had penetrated through to the health}- eye. Differ- ent disea.-es of the eye cause variations in the luminous sensations pro- dui-ed by electricity. < )p;icities and similar abnormalities of the refract- ing media do not result in any abnormal reaction to electricity, but most chanires in the optic nerve and in the retina do result in very great impairment ot tin- reaction. It may, therefore, be used as a delicate 1 ;ins ol ilia LTH eci nn " a ire. and is maintest at the making and breaking of the cur- - produced even when the current i- too weak to cause the is ima ire. In test ing t his secondary react ion the intensitv - increased until one has produced the primary luminous >' reaction. Alter tin- the current is progressively omes so weak that the making of the current still n ot liirht. bin the breaking of the current no longer 'U- phenomenon, 'i his is t he minimum current which indary rear-iion. and in a '.rival n.anv observations it ndary reaction in a healthy subject is very dways between ,',, and , :! fl niilliampere. beiic retinitis with papillary atrophv the a current ot at least , s :i niilliampere. ELKCTRODIAGNOSIS 3") subject, of course, to the intelligence and imagination of the patient, but this is also true of the measurement of the visual field. It is of experimental rather than practical interest. Electrodiagnosis in Ear Diseases. This is largely a matter of the production of sensations of noise produced by electric stimulation (page 4(>9), and also of the production of vertigo by galvanization. It may often decide 1 between a neuropathic and an organic lesion; also the seat and importance of the lesion. Ear lesions often cause the muscular sound due to faradization to be more distinctly heard than in normal ears. Voltaic Vertigo. This is a condition producing certain subjective and objective symptoms, caused by the application of a constant or galvanic current from electrodes 1 cm. in .diameter, placed one in front of the tragus of the right ear and the other in a corresponding place on the left side. It has a certain diagnostic value in diseases of the middle and especially of the internal ear. The patient feels dizzy and it seems as if the outside world were moving toward the cathode, sees sparks before the eyes, and hears a noise in the ears. There is nystagmus or oscillation of the eyeballs if the current is strong enough. An important objective symptom is inclination of the head to the side upon which the positive pole is placed. This symptom was first noted by Babinski. who has also found that a rotation of the head toward the same side may be produced by applying the electrodes in a special way. The condition is produced normally by a current of 2 to 4 ma., while in some diseased conditions of the labyrinth or of some other part of the internal ear. or an abnormal condition of the cerebrospinal fluid, it may require a current of 10 or 15 ma. In some cases of bilateral < lisea-se voltaic vertigo cannot be produced at all. If the head will incline toward one side and not toward the other when the polarity is changed, this fact shows that the lesion is unilateral. The condition is of diagnostic value in determining whether deafness after an accident is due to hysteria or malingering or to an actual deep lesion of the ear. Other cases of deafness and of Meniere's disease, and of intracranial tumors and of hypertension of the cerebrospinal fluid, cause modifications of voltaic vertigo which are an important aid in diagnosis. An organic lesion of one internal car causes inclination toward that side, no matter what the direction of the current. Faradic Contractions in Myasthenia. Normally, the myograph shows that the muscle remains uniformly contracted as long as the influence of a faradic current is applied, or at any rate for a considerable length of time. Fatigue does not begin for a long time. In myasthenia there is a steady fall almost from the beginning. The flexor of the middle finger is a desirable muscle for this test, and marked abnormality is found in alcoholism, pellagra, general paralysis, dementia prarox. senile dementia, neurasthenia, and epilepsy. Tracings in these condi- tions have been published by 1'ariani. 1 Electrodiagnosis in Alcoholic Peripheral Neuritis. There may be motor troubles, with or without the reaction of degeneration. In the first class of cases faradic excitability is a little diminished, and so is galvanic excitability; but then 1 art 1 no qualitative changes, though 1 Hivist:t di Patologia ncurosa < inciitalc. November, 190"). .y.ni MKDit AL I:I.K( run 1 1 v AND K<>\K,KX HAYS there i- hypersensitiveness of the skin to both currents. Cases with 1'eactioii of degeneration are quite rare. Alcoholic cases without motor trouble-; present practically normal electric react ions. Detection of Malingering or Hysteria in Paralysis after Injury. The fact that voluntary motion returns sooner than normal electric react ion- after a nerve injury is extremely important . In a case in which paralv-i- and the reaction of degeneration have followed an injury or a di-ea-e. 1 he ret urn of faradic excitability without the return of voluntary movement i- considered proof of malingering or hysteria. Record of Electrodiagnostic Examination. This should state the faradic and galvanic excitability and qualitative changes in the same mu-cle or nerve on both -ides of the body; thus: I '(/.v///x ExtcnniR M Hxrlt . Left. -- '.)\ cm. l-'anulic excitability 1> = 7, fi cm. , . , , ., i < 'ace = ."> ma. ( lalvanic pxcitamln v . i Ancc = s ma. 1 1 ' . lii itivr clKinirt 1 , -l"\\in---. (Qualitative ciian.irc. none. If t he faradic coil has an adjust able number of t urns in t he secondary coil and rate of vibration in the interrupter, these should be stated. 1 hey -hould normally be the same tor both sides. Various graphic charts have been devised, but the simple written record i- excellent, especially if supplemented bv a note to the effect. for instance, that the "galvanic and faradic excitability are both reduced. and there i- a slowness of contraction, but no inversion of the normal < ' mula." 1: the Leduc apparatus is used, the number of interruptions per minute and the fraction of each period during which the current flows -hoiiid he stated, and also the smallest number of milliamperes which c;tU-f- ci in* ract ion. 1 :i condenser i- Used, its capacity should be recorded, and also the '<'.'_ to : ch it -MI-! be charged, so that isolated discharges will " contraction: also the voltage which will produce tetanus from The Electric Resistance of the Urine and of the Blood. -lance of the urine at (i") F. in a U-shaped electrolytic >hm-. I ne greater the percentage of ehlorids. piios- alid other -all-, the less i- the resistance'. The mnaturally to l:!l) ' 'i '' >ii'i ' . : nd i he more abundant the re-i-tance. The saline constituents, especiallv I'.r :i : M. ili.'ai .iMiinial. ,Iulv L's. I'.KWi. KLKCTKODIACXOSIS 397 sodium chlorid, arc good conductors, and the more abundant they arc tlic less is the electric resistance. The electric rexixttnicc of the blood-cells and of other cells is measured by a method proposed by Xernst. The resistance of a liquid is first measured and then blood-cells are added to the liquid in a certain pro- portion and the resistance again measured. Rudolf Hober finds that the blood-cells have a conduct Utility equal to that of a decinormal solution of potassium chlorid, while the entire J)lood has a very much greater resistance. 1 The electric resistance of the lymph is regularly less than that of the serum. 2 The electric conductivity of the human saliva undergoes daily oscil- lations which show that it contains ioni/able salts in greatest amount on rising, then reduced, not much influenced by light repasts, but decidedly increased by the principal meal. J The electric conductivity of cows' milk is about 48.7, 10- 4 , and it has been suggested by Rinaldo Binaghi 4 as a test for adulteration. The Hemorenal Index. This is the quotient obtained by dividing the electric resistance of the blood by that of the urine, and it varies normally between 2 and .'>, the average being 4 l' > = '2. OS. An increase in the hemorenal index means a diminution in the salts in the blood, or an increase of those in the urine, or both. This is sometimes found in chronic rheumatism. , . . . . , . Resistance of blood. 51 A diminished hemorenal index, such as Resistance ot urine, 1 lo 0.44. was found in a case of pernicious anemia. It indicates inability of the glomei'uli to transmit salts from the blood to the urine to a sufficient extent. It explains the danger that accompanies .r-ray exposures in pernicious anemia, which throw increased excretory work upon kid- uevs alreadv deficient. PROGNOSIS BASED ON ELECTROD1AGNOSIS When elect rodiagnosis and other means show that the paralysis is due to a cerebral or a spinal-cord lesion, the prognosis depends upon the nature of the lesion more than upon the electric reactions. It is in the case of peripheral nerve lesions that the most valuable prognostic knowledge may be obtained from elect rodiagnosis. A case of facial paralysis from exposure or rheumatism may show a continuance of normal electric reactions, and if so. recoverv may be expected in about three weeks, or there may be galvanic and faradic hypo-excitability, meaning that recovery will take two or three months. The presence of the reaction of degeneration in such a case indicates a probable duration of six months, with a possibility of permanent paralysis. Lesions of other peripheral nerves are judged in a similar way. Complete loss of nerve excitability, with greatly increased galvanic muscular excitability, with sluggish contractions, indicates a severe 1 Arcliiv. fur die ircsam. 1'hysiol., rxxxiii, 2:57, l!)ll). '-' Luckhardt, . \nicr. Jour, of Physiol,, xxv. :>}.">, I'.MO. Ml. Polara. Archiv. italicnnos dV Bi<>l<>iJ<>. lj v . ->. HMD. 4 Hiorhcmisrlics Pathologic and Zur all^cmrinrn 1'athol.. \.\i.\, l)l)-7it. I'.HO. ot)S MKDICAL KLKrTKIClTY AND KOXTCiKN RAYS degenerative process. The possibility of sonic regeneration remains, however, as lontr as any elect ric excitability is present . but if a year passes without return of faradic excitability, and if the muscular atrophy has been rapid and invat. otilv slight iinproveiiienl can e\'er be hoped for. \\ ith an acute lesion and loss of faradic excitability inside of a week or ten da\> considerable atrophy will follow, and the motor power will lie slow to ret urn. If two or three weeks pass before faradic excitability disappears, the paraly.-is \\ill last many months, but there will be less atrophy. If faradic excitability remains normal or is but slightly reduced. recovery \\ill be^in in a lew weeks or months, and will probably be complete. IONIC MEDICATION BY ELECTROLYSIS A.v electric current may he made to carry medicinal substances into the tissues to a sufficient extent to produce certain physiologic and therapeutic effects. The positive electrode is usually selected for the active 1 one, because it is generally convenient to use a solution of some salt of a basic medicinal substance. When a salt is decomposed by the current, the ions representing the base travel into the body on their \vay to the cathode, and the application is known as cataphorcsis. The effects of basic ionixations are manifested chiefly in the tissues close lo the positive pole, though these ions may produce chemic reactions in the liquid with which the negative electrode 1 is moistened. It is easily demonstrated that particles of a substance ma}" pass entirely through the body, so as to be found on the surface of the opposite elec- trode from the one originally moistened with it. It is not at all certain, however, that particles of the substance exert any influence upon the deeper tissties through which they are transmitted. The effect seems to be due to the liberation of an element or a radicle in a nascent state from the solution in which the electrode is moistened: and it is an im- mediate effect upon the first tissues subjected to it. The ions are transmitted through the deeper tissues in a condition in which they gen- erally do not form combinations with the substances making up these tis- sues, or wit h ions traveling in the opposite direct ion. The two substances in the latter case may have* the stre>iige v st possible affinity for each other, and still show no chemic combination e-xcept at the two poles. The same force called electrolysis, which is strong enough to dissociate ele- ments which can be separates! in hardly any other way. is operative in largely preventing anything but a local el'fevt as the diree-t result of elect ric ionic medication. Merely dissolving a substance- in water converts a considerable part of it into ions. Ionic medication is, therefore, not a specific enough term in itself to indicate the- subject e>f this paragraph. Leduc 1 has summarized our previous knowledge 1 of the stibjevt of the electric introduction of medicines, and has added many valuable 1 obser- vat ions of his own. It has long been known that electrolysis takes place 1 at any point of contact between the skin and an e'lert rode which is a much bette-r con- ductor; that the primary effect at the anode is to liberate 1 chlorin, from tin- sodium chlorid of which the 1 conducting portion of the 1 body is practically a solution, and oxygen, from t he water in which it is dissolved. The chlorin is liberated at the positive electrode 1 , which it attacks, and an oxychlorid of the metal or other base is formed. A continuation of tin- effect dissociates the oxychlorid of the metal and carries metallic or oilier basic ions inte> the 1 tissues, while the chlonn and oxygen attack fresh portions of the metal. A similar process goes on at the cathexle 1 where sodium and hydmgen are liberated, and immediately combine 1 Ions ri Medication ioniijiif, Paris, l'.H)7. 390 UMI MKDUAl. KLKi TKK ITY AND KONTCKN HAYS with tin- acid element of the electrode it' the latter is a salt. A con- tinuance of t he process dissociates t his intermediate hydrogen or sodium compound, and carries the liberated acid ions into the body. If one wi- hed to produce the effect of hydrocyanic acid, t lie negative electrode \\ould be \\et with a -olution of potassium cvanid. while to produce I he effect of strv rl ill ill t he positive elect rode would be wet with a M 'hit ton i >:' .-I ryehnin MI! j >hat e. Experiments in Cataphoresis. S. Salaghi 1 has performed the following experiment u it h a view to arrest ing and fixing in t lie tissues the ion- which are carried there b\ a galvanic current: Four glasses . A. B, (', and 1) i Fit;. 1'v") arc placed in series. The positive electrode of a galvanic ban er\ dips into A, which contains a solution of nitrate of silver. Thi- :Ja-- i- in electric connection by means of a strand of cotton mesh with li. which contains a solution of sodium nitrate. (' also contains .-odium nit rate solution and is connected by a CMI ton mesh with I), which contain- a solution of >odinm hyposulphite. Hand Care connected by a tube containing a dog's sciatic nerve immersed in oil. A current of 1 _' ma. passing steadily for twenty-four hours will produce a precipi- tate of silver in several centimeters of the length of the nerve at the end Tube containing sciatic nerve ini- Cotton cord. mer-ed in oil. Cotton core ixation ill ions in the tissues alter catapnori'Sis. nearest 1 he anode. The precipitate is found exclusively in the myelin lie nerve-t ubule-. Another experiment by I.educ consists in having two rabbits sepa- ated by absorbent cotton wet with potassium cyanid: the rabbit connected with the anode is poisoned. But if the cotton were wet with ochlorate. the rabbit connected with the cathode would iimcation to the author Dr. (!. Betton Massey states meal to which a galvanic current is applied through amateil /me f/.iiic dipped in acid and then in metallic -hov, a Li'i'ay di>co]or;it ion, indicating a transportation a I id deposit Hi el nil if mercury. Rate of Transportation of Ions. It i.- important to remember 1 1 i! pa-.-aLi'e of t he elect ric currejit . about t he same as that of ;i '"''' - : " rent t lung li'om t he -pen 1 at which ions move through ! he -aim ' . Different ion.- mo\'e at fixed rat es of speed, which ' \ l . M h the eject t'oniot i\"e lorce \\hlch ill'l\'e- it. and length of eh'ctrolyte through \\hich the curi-ent ha.- i" a-- IONIC MKDICATION MY KI.KCTKOLYSIS 401 Silver ions move at the rate of O.lofi cm. per hour. Lithium " ().()'. J Sodium " " " " " o.'.iJC) Cerebral Effects of Medicinal Electrolysis, (Jautrelet ' has tested tlie effect of the >trong currents used in electrolysis near the head. I'sing the positive electrode with a surface of 100 square centimeters applied to a rabbit's ear, while the indifferent electrode is applied to the thigh, a current of o() ma. is allowed to How. The effects produced are of two kinds: an early effect, due to the electric current itself, and always seen, regardless of the nature of the electrolyte used to moisten the electrode, and a later effect, which is sometimes seen when such a substance as strychnin is used for the electrolyte. The effects directly due to the current are at first symptoms of peripheral irritation of the trigeminal nerves, movements of the face and of the eyes, and an in- crease of the sensibility of that region. There is a stimulation of the cerebellum, causing movement of the opposite paw; and bulbar stimula- tion. causing a change of the cardiac and respiratory rhythms and in- creased frequency of respiration; and a stimulation of the medulla, pro- ducing cont ract ions of a. good many different muscles. These phenomena of stimulation amount to epileptic convulsions in the course of fifteen or twenty minutes, the convulsions being at first tonic and subsequently clonic. The eyes protrude, the pupiis are dilated, the heart beats fast. At a subsequent stage paralytic symptoms develop, the conical reflex on the opposite side troin the anode gradually becomes abolished; spontaneous movements cease, and movements ot the nostni and face on the same side a. re abolished; the face is drawn toward the opposite side. Xo reflex occurs from a pin-prick: sensibility disapp< ;:- from the face and all parts of the body. In these experiments an application of about one and one-half hours was required to induce a genera'; paralytic condition, which was usually but not always recovered from, a small proportion of the animals dying. A very different result takes place when the circulation m the ear i- restricted by a clamp applied to the base ol the ear: in a very few minui i s the heart becomes regular, re.- pi rat ion very rapid, and paralytic phenomena are observed, especially Cheyne-Stokes respiration. Death endues m about an hour troin asphyxia, the blood being tound black and containing unreduced hemoglobin. In this experiment few if any svmpt on is of stimulation, and sea rceiy an v convulsive movement s. occur. If a substance, such as strychnin, is used, its special effects become apparent after a much longer time than the effect- directly due to the current. If the circulation in the ear is not impeded, the characteristic strychnin convulsions take place after fifty minutes' application, and the animal dies almost immediately. When the circulation i- cut off. the st ry chni n symptoms do not occur even alter the cessation ot the cur- rent or of the direct results of the current : but it the clamp is removed before t he animal dies, t he characteristic symptoms of st rychnin-poison- mg develop a few hours or a day later. (M course, in the latter case the current was .-lopped entirely after the application ot three-quarters of an hour. 402 MKOHAI. KI.KCTKKTry AND UOXTCKX KAYS Distinction Between Electric Ionic Medication and Other Ionic Medication. -Dissolving any substance produces a certain number of ions of that substance, and it is probable that all medication depends chiefly upon these active particles of the different substances. Klectric ionic medication is the production of ions, and their in- troduction into the bodv bv means of an electric current. The Author's Technic for Electric Ionic Medication. A four-cell hath is used p. lolli. Three of t lie .-hallow u'lass t rays com ain a solut ion oi sodium bicarbonate, and the fourth tray a solution ol the medicine to be introduced. 1 "he electrode in each tray is a carbon plate, and is covered by a piece of indurated fiber and felt. Another piece of felt is wrapped around the part at which the medicine is to be introduced, and the whole i- dipped into the tray containing the medicated solution. This trav i- connected with the positive wire from a table (p. 4(>1 ). which supplies galvanic, faradic. and rhythmic and ot her currents den vet I from the 1 ID-volt direct elect ric-li'ht circuit. The volt controller and the rheostat are both adjusted so as to irive no current. The connections are made for the galvanic current, and the rheostat and volt controller art 1 siTadually changed until the millianiperemeter indicates that a cur- rent of Ji i or more milliamperes is passing through the body. .More or less burning sensation is usually to be expected at the place where the medicine i- introduced, and the amount of pain furnishes a Lruide to tin- amount of current permissible. The four-cell bath referred to it tereni elect rode to be applied to eit her fool or either hand, and enables one to change from one to another bv movm.tr the wire from <>:.< bindinu'-post on top of the table to another. A burning feeling in t he fool or ha inl at t lie indifferent elect rode is an indie at ion for chan.innir from one limb to allot her. but before t his is done t he current is gradually (I to zero. The current is gradually increased to the original -'. !.'_! h after the new connection has been made. For the heaviest t~ three oi the trays may lie connected with the negative pole of the Lialvaiiic current . the more extended suriace of contact with three ni e.xin tn ties ;il the same nine preventing any discomfort from tiie indifferent electrode. This, however, does not lessen the painful effei-i at i he active electrode, and an anesthetic is required m some ca-f-. a- ill the u-e of ;i metallic /me electrode of small si/e covered ';. ; ' it h a 5 per cetit . solution of /.inc sulphate and a current of }i i to ^' i ma. for the cure of roth -i it ulcer. \\ eaker currents ma\' be used !o!' t \\ it I io ul an a in'- 1 he; ic. Adrenalin cataphoresis i- used as a means of blanching the tissues Mon ol t he nil ra violet rav. which \\'ill not penet rat e : blood. A () or 40 ma. Then another point is gradually introduced, and it will be found that the milliam- peremeter registers an increased current, due to the larger area of contact. Other points are introduced so as to transfix the tissues all around, and, if practicable, beneath the growth. The current may then be found to be .">() or (iO ma., the increased area of contact at the metal points having greatly reduced the resistance at the positive pole, while the resistance at the negative pole has not been changed. Additional current is now turned on very gradually until 100 or even 200 ma. are indicated by the milliamperemet er. The flesh is seen to turn white, and a white froth exud-'s from the different punctures. The exact length of time that the current should be allowed to flow varies with the amount of tissue that is to be destroyed. It is usually between five and ten minute-. The current must be turned off just as gradually as it has been turned on. and the last metal point must not be removed until the current has ceased to flow. The 110-volt direct current is most suitable for the work. This may be obtained from the direct 110-volt electric-light circuit, or from the alternating electric-light circuit, by a rotary trans- former or a storage-battery or a galvanic battery of the necessary number of cells to produce about 110 volts may be used. A motor dynamo, giving either alternating or direct current of 2 amperes and 110 volts, costs Si).") and is invaluable for direct current work when the electric-light current is alternating. (iood dispersing pads are es- sential and they must be sufficiently moist. If metal is too near the patient, pain limits the strength of current the patient can stand. Shocks from poor or rusted connections limit it. Massey avoids this trouble by using cotton-covered magnet wire No. ;->2 or oO. fresh lengths each time, and if the apparatus has not spring catches, put in a match stick with the wire in the binding-post. This treatment has been applied to cancers of' the breast and tongue, localities where turning the current on or off suddenly would cause serious shock. The advantages ot this treatment are the Ireedom troin hemorrhage, the mmplrtf dcst met ion of the part to which it is applied, the presence of a -terili/ed and u-ually i||-y sloiiiih. which changes into a dry seal) and come- away l>\ natural proce-se>. The disadvantages are that it does not have a selective action upon t he inorl iid I issue, nor one extending 1 icyond 1 he area act ually dest roved, and t hat it - ci cat rices a re very 1 >ad compare) I with 1 hose let t a 1 1 er a case ha- been cured tiy the .r-ray or liy suruical removal and a plastic opera- t ii in. While the method i- certainly a valuable one for use in occasional -pecial cases, it may not lie unfair to characterize it in some other cases a- an imperirci lorm ot suru'cry. There is a (|iiestion as to whether the destructive effect is at all due to the transportation of mercury into ha- iieeii used iii cancer of the neck of the uterus, as 'Aell M- ii e\i ma I '_L rowt h-. li ke t hosi nielli ioiicd a 1 )OVc. cancer nodules in the hreasl Massev' dest rovs the 'lie axillary content- iiy a liipolar ioni/ation of 1S(K) to ianc\ of a lump in the hreasl by fa radie current which [lainlul area- of chronic mastitis. Anv nodule week< daily laradixat ;on i.- either a cvstoma, and is to he de.-t roved. -'I IONIC MKDICATION MY KLKCTKI >LYSIS Cocainization by Cataphoresis.- The most successful method is to moisten the felt covering of the positive electrode with a 10 per cent, solution of cocain hydrochlorid in guaiacol, and to apply a currenl of f> ma. for about five minutes. This produces cutaneous anesthesia, but a doubt remains in the author's mind as to whether il is any greater than would be accounted for by the action of the guaiucol (a carbolic- acid derivative) without an electric current. The method has been employed for neuralgia, for the pain in locomotor at axia, and as a prepa- ration for small superficial operations. Fig;. 2S(i shows a suitable volt controller for dental cataphoresis. Electrolytic Medication in Middle-ear Disease. The materials employed by Malherbe 1 are solutions of sodium chlorid. potassium or sodium iodid, and pilocarpin nitrate. The strength of the solutions varies from '2 to o per cent . and the act ive elect rode ( posit i\'e wit h the first three substances and negative with pilocarpin) consists of a pledget of cot 1 on wet wit h the solution, and placed in I he external auditory meat us in contact with the outer surface of the drum of the ear. The other electrode is an olive-shaped one with an insulated stem, and is intro- duced through the Kustachian tube until it touches the inner sur- face of t he drum membrane. Rather strong constant currents of 1 to o ma. are used for seven or eight minutes three times a week. There is a feeling of warmth or of burning. There is a beneficial effect upon sclerotic and cicatricial conditions. Malherbe has treated tubal catarrh in the same way. having the anode in the external auditor}' meat us wet with a 1 percent, solution of tine chlorid and the cathode in the Kustachian tube. Chlorin lonization for Fibrous Ankylosis, Sclerosis, Dupuy- tren's Contraction, Sclerodactylia, etc. The benefit which has long been known to follow the application of the constant current in these cases may be due in part to chlorin ions from the salt solution often used to moisten the electrodes. The specific object of applying these ions requires that the active 1 electrode should be a large one. so as to permit of the use of strong currents of 20 to o() ma. and that it should be the negat ive electrode. Copper Electrolysis for Ring-worm. -This is a practicable method, but has not been employed to any extent. The object is to carry an antiseptic agent into the hair-follicles. The strength of current depends upon the area of contact: the application should not be strong enough or long enough to cause pain, but it must cause a distinct sense of warmt h. Copper Cataphoresis for Fistulas About the Jaw. A suggestion by the author is to make use of copper electrolysis for these cases, after making sure that there is no retained broken root or root filling. A small area ol necrosis can be cured by this means. The current should be (> ma., or as near that strength as the patient can stand. The po; sterilized in this way. If not, there is danger of -hock and al-o of the tooth being discolored. Copper Cataphoresis for Infected Punctured Wounds with Chronic Fistulas. A copper positive electrode is passed into the ti-tula. and a current of i> or s milliamperes is allowed to flow for six or lies, when the current is irradually reduced and a reverse current of _' or '> ma. i- allowed to flow for a short time to loosen theelec- . the flesh. Treatments are u'iven once a week, and result in a cU!'f 111 t lll'ee or toll!' weeks. Magnesium lonization for Flat Warts. A piece of absorbent iti in _' cm. in thickness and with a surface of ]()() cm. was moistened \ it h a .") per cent, -oli n ion of magnesium sulphate and formed t he posi- live electrode. A current of 10 ma. was applied for fifteen minutes. I ... ' days ;t ft er the first t reat m en t the skin was smoot h. and over almost lie surface treated the warts had become flattened and effaced. Some disappeared without leaving any trace. Most of them, however. were leplaced by a little yellowish-brown spot : others felt a little bit roiiirh. < >nly two t r< at ments were required at intervals of eiVht days. and five or six days after the last treatment the skin was entirely normal. Tin-- i- the hi-tory of a case of multiple verruca ])lanus of the face. ited in ilu- way by Bordet . after all the usual methods of treatment h: : failed, aiifl even after t he application of high-frequency sparks had produced linle effect. Magnesium lonization in Fungating Warts. A case in which '!''- treatment was tried by Bordet did not yield promptly. The ' ; measured Of) sq. cm., and a current of 15 ma. was applied for Seven or ei^ht small flat warts disa]ipeared in the ' three treat men Is. but t he fungal hm ones were so lit t le ' IK- destroyed them by t lie galvanocauterv. lodin Anaphoresis for Goiter. A solution of potassium iodid or din iii one o] pota.-sium iodid i- used to moisten the felt ive ele<-troile. I he process is one of aiiaphoresis. not - 1 ' he active atrent i- one \\-hich seeks the anode 1 he electrode mil-! be a lai'LTe one. curved ectrode i- a hirji'e one. and is placed at some i!ai care must be exercised in t urm'tm' t his ni on and oil gradually. Ajmlicat ions are !'i ' ) Hit e painful. ' ' seldom cause- t he com pi et e disappearance pM-.-ili that it ma; be due practicallv entireh" to '- ' llTenl and :. H Iii I he iodin. lodin Anaphoresis for Chronic Suppurative Adenitis. A metho.l !) in :i ' '.I-IMII-, April. I'.MT IONIC MEDICATION BY ELECTROLYSIS 40 1 which is useful in cases where it is very desirable to avoid an incision and consequent scar is by aspiration of the pus, injection of a solution of iodin or iodid of potassium, and introducing a needle, insulated except at the point, and connected with the negative pole of the battery. The other electrode is applied at some indifferent place. A current of 10 or 1") ma. is gradually turned on and allowed to flow for ten minutes. Three or four applications usually effect a cure. Iodin lonization for Gonorrheal and Tabetic Arthritis of the Knee. Successful cases have been reported by (iiovine. 1 A solution of pr- tassium iodid is used to moisten the large negative electrode which is wrapped around the joint. Acute tonsillitis may be treated by a padded electrode at the back of the neck, and a probe wrapped in cotton wet with o per cent, zinc iodid. A galvanic current of 15 to 20 ma. is applied to the tonsils for five or ten minutes. Kesteven says that pain is quickly relieved and the swelling reduced in forty-eight hours, two or three applications usu- ally sufficing. Chronic indurated cases require a 10 per cent, solution and eight or ten treatments, three each week. The negative pole is applied 1o the tonsils, as iodin is an anion. Hypertrophied turbinated bones are treated by ionizalion with a 2 per cent, zinc iodid solution, two or three minutes at a time. Smarting is allayed by a carbolized powder (Kesteven). Zinc Cataphoresis for Fistula in Ano. --These cases have always been extremelv difficult to cure by this met hod. but an improved technic suggested by Bilinkin has resulted in a number of cases being cured. The positive electrode consists of the finest kind of a zinc rod or needle, and it is coated with paraffin except for 1 cm. at its distal extremity. It is introduced to the bottom of the fistula, almost but not quite entering the rectum. A current of 6 ma. flows for three minutes, and the bowels are kept constipated for three days by means of opium. At subsequent treatments the electrode does not pass so far into the fistula, and the strength of the current is gradually reduced. From six to twenty treatments are required to effect a cure. It is most likely to suc- ceed in cases where the patient is strong and has no tuberculous trouble. It may do considerable good, however, even in tuberculous fistulas. Zinc lonization for Epithelioma. The best solution is 1 per cent, chlorid of zinc. Leduc uses a current of 2 ma. per square centimeter of surface to be treated, and an application lasting fifteen or twenty minutes. Lewis Jones uses much stronger currents, but still quite endurable, and a shorter application. Cocain may lie required, but not a general anesthetic. A zinc electrode is used, and cotton wet with the solution may be lied around the <;lectrode or simply laid upon 1 lie ulcerated surface. The effect of an application of 10 ma. for ten min- utes is to impregnate the superficial tissues with zinc ions and to turn them a dead-white color, which, however, does not indicate 1 necrosis. A little later the surface becomes red and remains somewhat inflamed for a week. Soothing applications are required, and no further electrolysis probably until two or three weeks after the first application. Two or three applications are required. Zinc Electrolytic Medication in Gonorrhea. A soft-rubber catheter with multiple eyelets is used to irrigate the urethra with somo solution, such as \ per cent, solution of sulphate of zinc, which form-* 1 Kiformn Milieu. November 2. 1907. (IIS MK1MCAL Kt.KeTKK 1TY AND KONTGKN HAYS the positive electrode for a current of from 1 to 10 inn. Bouchot 1 makes the electric connection with the liquid l>y the use of a fine platinum wire, which paxes through almost the entire length of the catheter, and which is fastened to a metal tul>e inserted between the tube from the irrigator ban and the catheter. It i- to this metal tube that the positive wire is secured. The other electrode is applied to any other indifferent region. An irrigation with '_' quails of solution is enough for each application. In acute crises, \\here the treatment is begun on the iirst or second day of the disease. Boiichet lias found that daily treatments cause immediate disappearance of the discharge and sterili/e the urethra of gonocoeci in fourteen days. In :'>0 chronic cases he obtained a complete cure in three or four weeks bv applications made every other day. Hi!--, of London, recommend- the treatment of gonorrhea by the direct continuous current by a stylet encased in a rubber tube with per- forations at MS distal end and filled with a very low percentage of silver salt and iodin: the current is first in one direction and then in the other. Ma-svy' s tll vu-(.sts a copper stylet and 1 per cent, copper sulphate. Zinc Cataphoresis for Alopecia. LeducV experiments upon rabbits rendered bald bv tinea show that the application of a positive electrode wet with a 1 per cent, solution of chlorid of zinc causes rapid irri >'.'. t h of the hail 1 . Chronic Hemorrhagic Endometritis and Chronic Ulcer of the Leg. Xnic cataphoresis is excellent in both these conditions. Lithium lonization in Gout, (iuillo/'s method has been used success! nllv in a lame number of cases (70 ot his own reported). The atTected limb rests in a porcelain basin filled with a '_' per cent, solution ot a In ii m m salt . wit h enough lithium hydrate to alkalim/.e it . The posi- tive electrode i> placed in the solution, and a large indifferent negative electrode i- applied over the lumbar region, (iiiillox graduallv turns on a current of 1 .">( > or L'OO ma., and allows t his to flow for t went}' or thirty minutes, lie terminates the session by fifteen minutes' high-frequency aii'ocondiict ion. I'reatments are Driven ever\' da\' or perhaps twice a day. I'he re-ults are relief of the local symptoms, a rapid reduction in Aeiiiln. a cure of the attack, and prophylaxis against other attacks. 1 i'liitv deposits often disappear. It must be remembered t hat these are heavy currents. In be applied for such a length of time. ; t he u.siial care mu-t be taken ' o prevent shocks or burns. Bipolar hiidi-l reqiiencv e|Iiu\ ia ! 1011 ma\' be substituted for auto- ' ioli in t he above techllic. f'.lect ric-1 i'_:hl bat hs are of Verv irreat n ' ca-e- \\here catMphoresis and high-frequency currents I'" 1 . ' toimd uric acid in the -olutioli \\ith \\hich the posi- uei durniL: lithium cat a jihoresis. nipping the .' 'i il a sail ot lithium, uhii'h forms I he anode, lithium be (i a ri 1 1! the -\ -' en i 1 >\ the r u r re nt . and will a p pear in the illld be Used |f il l- desifeil to \\)\ ]> iduce 1 he acid IONIC M INDICATION I',V KI.KCTKOl.YSIS 409 solution of lithium (-blond, \vilb about ,,,-' of litbiuin hydrate, just enough to render tbc solution alkaline. I ric acid is a great many tunes more soluble in a solution of a lithium salt than in the normal fluids of the body, and this is the theory of t his applieal ion. Salicylic lonization in Acute Rheumatism. A 4 per cent, solution ot sodium sabcylate mav be used to moisten the negative electrode, and a current of from ."> to !."> ma., depending upon the si/e of the electrode, may be applied for half an hour to an hour. Bordet' reports the cure ot a case ot talalgia ]>v three treatments; of a case of tendinous articular rheumatism by ten treatments; of a case of acute muscular rheumatism by se\-en treatments; and of a case of acute polyarticular rheuniati.su] by nine treatments. Salicylic lonization in Migraine of the Arthritic Diathesis. According to Hartenberg," an attack of sick headache in these cases is due to arterial spasm, probably from irritation of the cervical sympa- thetic, and this he considers due to a rheumat ic infiltration of the tissues, especially the muscles ot the neck. Parts of the muscles are sxvollen and lender. If the swelling is recent and subacute, it is elastic and supple, but if it is inveterate, there are hard nodules in the muscles. There may also be indurated glands, thickening, and infiltration of the skin. This condition irritates the superior cervical ganglion of the sympathetic, which becomes sensitive to pressure. Electrotherapy, xvhich removes these infiltrations, cures the sick headaches. Salicylic ioni/at ion is employed. The negative electrode is placed around the neck, and is moistened with a "20 per cent, solution of so- dium salicylate. The positive electrode is at some indifferent place. A current of from 15 to ;">() ma., according to the si/e ot the electrodes, is allowed to floxv for one-half hour. Kecent muscular swellings disappear in twenty treatments. The harder ones take a longer lime, but disap- pear with the glandular and cutaneous infiltrations. The sick headaches are benefited during the first month, and are cured, but occasional treatments are desirable to prevent relapse. Salicylic lonization for Muscular Rheumatism in the Lumbar Region. Each electrode measures by S inches and the negative electrode is wet with a 4 per cent, solution of sodium salicylate. and placed at the seat of the greatest pain. The other electrode is placed a few inches away, either above or below. A current of from .")() to SO ma. is u'raduallv turned on, and allowed to floxv for from fifteen to sixtv Salicylic lonization for Sacrovertebral and Sacrococcygeal Arthritis. This has been successfully employed by Border 1 in cases ot such severity that the patient was confined to bed. The negative electrode is wet xvith a 4 per cent, solution of sodium salicylate. and is applied over the painful articulation, xvlule the other electrode is at a point near the spine, a few inches higher. A current of .'!() or 40 ma. for about txventy minutes every day is required, and each treatment max be terminated by faradization xvith a fine wire coil and a moderate strength of current applied bx a roller electrode. Salicylic lonization for Tic Douloureux. This has been used by 4in I.edue' 1 and others with a certain proportion of euros. The negative electrode i.- a sheet ot' metal conformed to the shape ot' the portion of the face affected, and covered with absorbent cotton wet with a solution of -odium salicvlate. A cunviii of about 'Jo ma. is allowed to fiow_ for about an hour. The process i- the reverse of cat aphoresis. tlie ions desired hein-: the acid ions which (low away from the cathode, and not toward it. The indifferent electrode must be a laruo one to prevent m such a strength of current for so lorn: a tinic^ One or ,,-,, ,,i tl u . n -lls ,,i a tour-cell bath serve admirably as the indifferent electrode. INDICATIONS F<>R K )NT( >PIK >RKS1S > MJ (_ Zinc iuntophore-is. Secondary infections of Zii/_- iontophoresis. ec/enia or oilier se- | Cathode of amalgamated zinc, creting dermatoses. | Sluggish wounds. Fpithelioniata. Acne. Furuncle and anthrax. Alopecia areata. Falling of hair. Sycosis. Tinea. Fistula-. ! \ erniga. ffiollt. Recjuircs a ficneral anesthetic, and .r-ray is better. Zinc iontophoresis. ( 'opper iontophoresis. ( 'opper iontophoresis. Magnesium iontophoresis. ( Salicylic iontophoresis. loilin iontophoresis. I-'.lectrolvtic baths. 1 CM. Am.'. CM Li. KI. Ns,S,( ).. iontophoresis. Blennorrhagic rheuma- | Salicylic iontophoresis. tisni. I Fibroii:- anchylosis. I I<>din iontophoresis. | Quinm iontophoresis. 1 -.m jtimin iontophoresis. . Cocain and guaiacol iontopho- resis. Salicylic ionto])horesis. Zinc anode iontophoresis. lilennorrhatiic urethriti-. /me anode iontophoresis. Blennorrhaiiic urethriti-. gelatin liuuuie anode impreg- nate' 1 wit h nitrate i if silver. lodin iontophoresis. | \on--uppurat ive ;i i |enit i<. tiun-.. Suppurat ive adcnit is inject ion of K I -olution, with evacu- I ated -a' 1 .-ill- 1 then galvanic current . i \nude -u! ut PHI _' to .", per cent. Na< '1, KC1. ur I\F i ( 'MI hi pile ~i >!i it inn _' tu ."i per cent . pilocurpiii nitrate. Ionic Medication by Means of High-frequency Currents. An p irpo-e Kie.. 'Js? eon i- i-diiiieeted \^i t h the <>udin resonator or with one pole of the IONIC MEDICATION BY ELECTROLYSIS 41 1 d'Arsonval transformer. In the latter ease the patient holds a metallic electrode connected with the other pole. The flat surface has a recess in which is fixed a sheet of asbestos moistened with the medicine to he employed. There is certainly some effect upon the skin from the vapor- ization of the medicine by the shower of sparks employed, but it seems ex- tremely doubtful whether any effective amount of the medicine is carried into the tissiu>s by the currents. High-frequency currents are alternat- ing, and one of the primary conditions of cataphoresis, electrolysis, and polarization is a unidirectional character to the current. When one wishes to prevent electrolysis and the like, the first step taken is always Fii;. 2s7. Electrode for ionic medication by means of high-frequency currents. to make the current an alternating one. The effect of iodin upon the skin is, however, very much increased by this application. Chlorin Iontophoresis in Rheumatoid Arthritis.- Where there is a boggy swelling around the joint wrap joint with twenty thicknesses of lint wet with a sterile 2 per cent, salt solution. Tin-foil and oiled silk are outside of this, which forms the negative galvanic electrode. The positive indifferent electrode should have a larger area. The density of the current should be not more than 1 ma. per square centimeter. This is applied thirty minute's three times a week. It may free the ankylosis. 1 A finger-ring should not be worn because of possible con- centration of the current: in fact, Humphris reports a burn under a finger-ring from 25 ma. for thirty minutes. Various Opinions as to the Value of Electric Ionic Medication. Ziinmenr believes that there is nothing but a surface effect from the ions of medicinal substances which are used to moisten the electrodes, and that the deep effects, beneficial or otherwise, are due to the current itself. The last clause means, of course, the tissue ions which transmit the current, and which in reality constitute the current. Iscovesco and Matza :t have performed experiments in which they tested the electrolytic introduction of medicinal substances into gelatin containing ,';, per cent, common salt, and found only a surface action with potassium permanganate. A layer was produced upon the sur- face which prevented further progress of the colored particles. The result with copper sulphate was the formation of copper chlond. which penetrated into the gelatin at the rate of 1 cm. (0.4 inch) in several hours. The result with iron acetate was the same as that with potas- sium permanganate. Their conclusion is that it would be more effective to give a hypo- dermic injection of the substance to be introduced into the living body than to u.-e the elect rolvtic method. 412 MKDHAL KLKCTKICITY AND KO.NTOKN RAYS Tutiier and Matite have experimented with salicylic ionixat ion, and have obtained tlie characeri.-t ic color reaction- in the most super- ficial laver- ni" the epidermis, hut never in the subcutaneous cellular tissue. Lat teiix and Ximniern 1 have seen part ides (if copper deposited at the surface of the uterine mucous membrane in a rabbit, but never in the deeper I issues. (iaUtl'elet (December _.">. 1!<>7). in testing the effect of different met; llic ion- upon the heart in fro^s. drew the conclusion that, under tin n-ual conditions of electrolytic medication in man. the ions which are int n>d need form combinations with other ions, and produce a local ' '. but do not enter the general circulation. ["ro^s were placed with one hind foot in a solution of potassium hlorid. iron ch'.orid. maLnesium chlond. etc., and the other hind foot in a _' pi-r cent. -olution ot sodium chlond. while a current oi _' ma. was d to flow. The metallic solution was connected with the positive pole. I he movements of t he denuded heart were registered by a .Ma rev's c; rdi' i^raph. ifi.- conclusions were that potassium, mercury, and copper ions art essential poisons to the heart muscle, acting onl\ sliiditlv upon the cardiai nerves. Magnesium ion- .-top the heart'- action by an effect ipon its nerves. Trivalenl iron ions slightly paralyze the heart muscles, but act ::- a violent poison upon the nervous system. Divalent iron ion- and calcium ion.- are tonic- of the cai'diac muscles, but in laru'e loses ad a- a nerve poison. Sodium and silver ion- do not produce much effect, although the iir-t slightly stimulates the myocardium, and 'he latter Cumulates the cardiac nerves. HrtVard has not succeeded in the ionic treatment of ankylosis of the lariM' joint-. even it of traumatic origin. He doe- not believe that the medicinal -ubstaiice is carried beyond the follicle- in the skin, and Chinks that whatever effect iV obtained in joint cases is due to the electric current and not to substances u.-ed to moisten the electrodes. .Iu~: as the effect of ha-ic or cation- i- manifested at the' po.-itive pole, so the acid or an ions produce t heir effect at t he negative pole. The soiution oi common salt, so(lium chlond. which is otten employed to nidi-ten t he eject rodes for ordinary t herapeut ic and dia.u'iiost ic purpo.-es. an ion-, and produce t heir effect upon t he tissues do-e to the neL r ;tt ive pole : roni \\ hie] t }, ( .\ -tart on their pat hs toward t lie posit i\'e jiole. Xa-cent i- n-pon-ible for part of the irritation produced when -odium i' ion i- u-cd to moi.-t en t lie elect ro(les. and u hid i mav be pre- '. ' ol '".'. .'.'- 'ijijiln'il u itli the same precaution- as de.-cnhed under the head of Mercuric ( 'ataphore-i- p. 102 . the only difference being that platinum needle- are u-ually employed, and that it has been cus- tomarv to a\'oid the po->ibility of -hock by u-iim both pole- actively. I i ' ' ' ' ' ' - : tin po-it ive and ne^a t r. e elect rode- are t hru-t into the i u ' periphery of the tumor. an coulomb per square centimeter of me- tallic contact at the negative electrode, and a current for about five minutes. The strength of the current will vary from o to oO ma.. depending upon the size of the electrode. The current for the cure of nevus by electrolysis without destruction of tissue should no1 exceed about 20 ma. per inch of length of positive needle in electric contact with the tissues for about five minutes. A greater strength will produce slough- ing. Twelve to twenty galvanic cells in series will supply the necessary current for treating nevus, but as they may very quickly run down, a storage-battery or an arrangement for ut ili/ing t he direct elect ric-light inu current is preferable. In these and other cases the current density is almost exactly pro- portional to the voltage, and if this is maintained at a uniform figure, it d,>os not matter so much whether a larger or a smaller surface of the electrode is in contact with the tissues. If large galvanic cells are used, the voltage will b" practically constant, and will depend upon the num- ber of cells in series, each cell yielding an electromotive force of about I , ",;'',, volts. The same is true of a stora.ge-bai tery, but each cell in series vieid^ about '_' volts. ("sing either twelve large ualvanic cells or ten storage-cells in series, or arranging the table for utilizing the oloctric- hidil current in such a way as to yield Is volts, a suitable current would be obtained for the treatment of nevus by bipolar galvanopuncture. while a considerably greater number of ceils would be required if the monopolar method was used, and an indifferent .-ponu'o electrode was applied to the surface of the skin. In the treatment of superfluous hair the voltage again is the important thing, and is Usually found to be (i or S volts. The proper voltage is secured by adjusting the appa- ratus in the treatment of the first hair-follicle, and i hen then 1 is no fur' In 1 r regulation of the current while different hair-follicles on t he same par! ot the face are under treatment. 1 he same number of galvanic or the same adjustment <>t the volt controller same current density, though the varying icles will allow of different areas of contact, and the milliamperemeter will indicate a different current strength. The same effect is produced over a larger or a smaller surface when the voltage is constant, and the milliampcrage varies in consequence ot variat ions in t he area of coin ad . It would be wrong to select a certain number of milliamperes and applv i hat strength io every hair-follicle, varying the voltage to over- 114 MEDICAL ELECTRICITY AND KONTCiEN RAYS conic differences in re.-istance due to inequalities in the area of contact. The same number of milliamperes passed through half the area of con- tact would have twice the current density, and would produce a much more -evere rttect . The milliamperemeter is the only measuring instrument required, although a voltmeter in addition would, of course, give direct readings of vultaire. and would, therefore. l>r very convenient. The regulation of t he st relict li of the current is effected bv a cell-selector, and per- liap- a rheostat and volt -controller in the case of galvanic or storage- cell-, and l-.y a volt-controller and rheostat when the direct elect ric- light current is used. The milliamperemeter shows whether all the connection.- are right, and a current of the proper direction and about the proper strength is flowing. A simple voltmeter may be improvised by connect im: the two conducting cords with a 16-candle-power electric- light bulb, and noting the number of milliati'peres registered by the milliamperemeter. AYe know that 2.10 ma. require a voltage of 110, and -o m a rough way 1 he number of volts is one-half the number of milliamperes which the batterv will drive through a 1 (i-candle-power incandescenl lamp. The electrodes are not connected with 1 he patient during the measurement. Having once adjusted the apparatus for the proper voltage, it is easv to keep it there or to reproduce the same ad- justment. >' ( nt/th of ( 'urn nl fr !) Klcctrolijxifi.- The diffusion of the current from a small area of con 1 act with 1 he elect rode is so great that no current which can be borne by the skin where the current densitv is greatest will produce much direct effect upon a deeply seated organ where the current density is least. A reflex effect is often obtained, and is fre- quently verv beneficial. The skin over a deeply seated organ is often ivflt-xly connected with it. The means for producing a direct effect con-i-ts m ii-m L: extremely large electrode.-, covering the whole joint 01 other organ to be treated. Two object- are accomplished: the lines "t radiation traverse the deeper parts in abundance, perhaps even giving a greater current density at the center than at any part of the -urface, and the large area of surface contact permit.- of the passage fit ven heavy currents without undue current densitv. A deep-seated . in thi- wa v be t ra versed bv current - a:- -I rong as t hose ordi- to the skin. Here again 1 he proper current densitvat the ' in coiit act u it h t he elect rode is verv import a nt . and it is secured by pr< iper regulai ion of t he volt age. I he current density is u.-uallv not more than 1 or '2 milliamperes per -quaff inch ol surface ot the -malle-t electroije for a continuous at ion null >- |i is desired to produce an elect rolvl ic effect . 1 f t his 'heca-i i er elect rode may be used for t he act ive elect rode, bill 1 1 ' ' : "' n : ' elect rode .-ho u Id be large enough to com pi v with t his rule. 1 '' n' electrode, for instance, has to be of an area of over 100 < ' ' ' \\hen a current ot '_'.~>O ma. i- u.-ed for the cataphoretic or i ic de-t rud ion ol a ca ncer ot I he brea.-l b\ mono polar gal A a no- [. Hid I . Electrolysis for Hypertrichosis. A fine iridoplat inum needle is |)ole ol t he 1 ia t t cry. I he po.-it ive elect n >< je pt.n-je elect {-, ,je the insulated handle of which i- held by the 1 1 brea ks cont act h\ p re-sing the pal m of the hand I hi- enable- the operator to have both hand- free, IONIC MEDICATION BY ELECTROLYSIS 41", for support upon the patent's face, and to hold the handle of the needle (Fig. 288). Before the current is turned on the needle is introduced into a hair-follicle, eathoterizing the follicle to its very bottom. Then the volt-controller and the rheostat are turned on so as to allow a current of from '2 to ~i ma. to flow. After five to twenty seconds the patient is told to let of the sponge gradually and the. current ceases to flow. Another hair-follicle not too near the first is then catheterized, and the patient told gradually to press her hand upon The sponge. The rheostat is not changed for each hair, but when passing to another part of the face which may be more 1 sensitive, it is well to reduce the current to zero before catheterizing the first hair. The exact length of time that the current is To be allowed To flow is not To be measured by the clock, but by the effect. A little foam forms around the needle and sometimes a little redness. The hair should come away without any traction when seized by epilation forceps. It requires some little practice and judg- ment to destroy the hair-follicles without undue scarring. Kven an expert will have To count on 20 per cent, of the hair returning. Scarring cannot be avoided entirely, but it is very much less if successive Treat- ments are t wo days apart and if no follicles very near toget her are treated at the same seance. Too long or too strong an application will cause bad pitting, almost like that of small-pox. As the removal of a com- plete beard requires the destruction of 10,000 to 20,000 hairs of large or small size, and as it is impracticable to remove more than twenty to fifty at a sitting, the tediousness of this method of treatment is self- evident. The removal of a few large coarse hairs scattered among the fine lanugo hairs is a less staggering proportion, and so is the removal of a few coarse hairs situated at the corners of the mouth. But even 41(5 MEDICAL KLK< TKirlTY AM) l )\T< , K\ KAYS these in;iy involve a course of treatment extending over a year or two. After all the hairs whieli it is desired to destroy have been removed, a certain number are bound to return, and others which were not removed seem to become coarse and require removal. The patient should return after two or three month-, and everything objectionable should be re- moved. This ha- to lie done over and over aji'ain, and will eventually succeed. If a >teel needle i- used, especial care must be taken to make sure that it i- connected with the negative electrode. Positive electrolysis with a -teel needle would produce indelible staining of the skin. Needle- with a bulbous instead of a sharp-pointed extremity are recommended by Ilumphris ("Electrotherapeutics for the Practi- tioner , who al-o recommends that hairs which are not loosened bv a safe cm-rent -hould be forcibly pulled out. They will certainly return, but then may be destroyed. Kubbin feels 1 1 l.e a hard, solid mass. o] - " all Va-ciila)' tumors i- accompllsheil b\- the use of a ' ' -heilac. c\cep| al ii - point . This is to be In rat ed t here, cans inn coa n u hit ion necrosis. I'li-d n>l\ >i- a platinum stem I or.") nun. in diameter or ll Ilia \' be made ol c a i lion. Tl 1 1- d isen^a.u'es a n . c iiii eri/i - a ml d i - 1 ni ert - the in erine ca vit y. ' ' h' p cat hoi].' i- u-ed, and t he I'auteri/a! ion is b\' bases. Electrolvsis for Vascular Nevi . ! lal nevi uilh visible telanjiiecta- <<:'.< >\ b\ elect rol\-i-, and if \'er\ small. I he irnlvano- IONIC M INDICATION BY ELECTROLYSIS 417 indifferent spot. A current of ^ or 4 ina. is applied for about five min- utes. If the skin turns white :iround the needle, it is time to stop, as t'uil her application will cause destruction of tissue. Larger flat nevi are usually treated by bipolar galvanopune.turc. The positive needle is kept in one position at the middle of the nevus, and the negative needle is thrust first into one adenoid vessel and then into another until several have been treated at the same session. The treatments had better be given once a week; from 'JO to -10 ma. are required, and an application of about five minutes. The current should be gradually turned on after the needles are in position, and should be reduced to zero belo re t liev are 1 a ken out. The negative needle becomes very loose, and care must be taken not to allow it to slip out and break the circuit. \\ ith a current of this strength a disagreeable shock would ensue. I. afire nevi are best treated by the bipolar method, the needles being thrust in for .', inch or more and bemu; parallel with each other and Fit:. -".)(). -Met hod of witli the surface. The idea is to cause the vascular tumor to be trav- ersed hv a current of uniform strength at all parts. Too marked an effect upon t he t issues wi m Id cause sloughing, and t his is not at all neces- sary in order to effect a cure. The appearance of lividity or blackening of the tissues indicates too long or too severe an application. Port-wine Stains. The electrolytic treatment of these birth- marks is accomplished by the bipolar method. Tin 1 positive 1 needle- is t hrust into a certain part of the port-wine stain rat her near t he periphery. and a series of punctures are made around n with the negative needle. Several such positive- punctures surrounded by a circle 1 e>f negative punctures are required, The-se- should be tar enoujjh apart to piwent confluence of the superficial sloughs. The current should be of a strength of from JO to 10 ma., and the usual precautions are- taken to prevent shock. The results are not so uniformly satisfactory in the treat me-nt of port-wine stains as in the- treatment of the- smaller ne-vi. 418 MEDICAL ELECTRICITY AND KONTGEN RAYS Tin Liqniil-dir Triatrnint of I'/irt-irinc Xtainx. This has been used successfully hv 1'usev. Ife uses the sno\v or frost formed by exposing liquid aii' in an open vessel. This intensely cold, white, powdery mass is spread light Iv over the port-wine stain. As it gradually disappears in the form of ordinary air. intense but superficial free/ing of the tissues takes place. This is followed by a superficial slough, and in cases which he has reported the improvement in appearance has been very marked indeed. Carbonic acid snow is used in the same way. Tin Triiiti/n ill <>f I'nft'iri/if N/ar/f.s hi/ X-rin/. This means of treat- ment i> considered on p. 1 1TS. Electrolysis for Hairy and Pigmented Nevi. One method of treatment is by electrolysis of each of the different hair-follicles, using the same technic as for hypert richosis, and this usually causes a suffi- cient disappearance of the entire nevus. If an additional treatment is required, the base of the nevus may be transfixed by two or more negative needles parallel with each other and with the surface, while the positive electrode is held in the hand. The current sufficient for the first part of the treatment for the destruction of hair-follicles should be from '_' to .") ma., while for the second part of the treatment a current of from 20 to '>() ma. is required. The ./--ray may be found preferable when the hairy nevus is very large and all the hairs are very coarse and strong. Eli / ;/*/N fur ll'a/Y.s'. Negative monopolar galvanopuncture or bipolar galvanopuncture with a current of 20 to ')() ma. destroys these irrowt hs. I reatment by the .r-ray or by the application of radium is somewhat to be preferred, and high-frequency sparks are wonderfully effective. Electrolysis in Acne and Acne Rosacea. --Large comedones may be treated by the same technic that is used for hypert richosis. llyper- ; rophy of the nose requires electrolytic treatment of the different folli- les. and after the subsidence of inflammatory reaction, may be treated by unipolar negative galvanopuncture. The current for the first part it the treatment should be of a strength of about o ma., while for t he -econd part about 20 ma. are required. The results obtained are very Liood indeed, but . of course, 1 he met hod must be applied wit h great care to prevent -earring. By another method, the electrolytic needle is applied for acne with a current of 2 to 1 ma. for three to five minutes, ignoring the anemia, which occurs in a few seconds. 1 Angiokeratosis and tattoo-marks are treated in the same way. Elec- tr ily.-i> i- "i doubtful utility in lupus eryl hematosus. Sycosis i- sometimes treated by an electrode wet with 2 per cent. solution ot corrosive sublimate, applying a rhythmically reversed cur- rent tor fitly minutes, or better, several shorter treatments. This is culo-i- i- -Micressfully treated l>y cataphoresi rm-ive -ublimate or of /.me sulphate. oiiier lia.- tri<-d cataphoresis with ergot in with encouraging acne pi-area of the no-e and cheeks. trliinir of lichen ruber is relieved bv ouinin catanhore-is. IONIC MEDICATION BY ELECTROLYSIS 419 Phagedenic chancre may be treated by corrosive sublimate cata- phoresis. For cocain cataphoresis a o or 10 per cent, solution is applied for ten or fifteen minutes and the anesthesia lasts thirty minutes. Dermatitis papillaris capillitii may be treated by the negative gal- vanic needle, but the a>ray lias given much better results in some cases under the author's observation. Electrolysis for Sebaceous Cysts. If excision cannot be per- formed, the cyst may be destroyed bv galvanopuncture. The positive electrode is so arranged as to surround the cyst at a distance of \ inch from it. The uninsulated needle connected with the negative pole of the battery is thrust into the middle of the cyst, and a current of from S to 10 ma. is applied for two or three minutes. The needle is then removed, and occlusive dressings are applied: two or three days later an insulated needle is thrust through the slough, so as just to reach the wall of the cyst, and a negative current of about 10 ma. is again applied. Three days later it may be found practicable to express the entire soft- ened mass through the little opening which is left by the removal of the cutaneous slough. Electrolysis for Keloid. Negative monopolar galvanopuncture current of about 5 or 6 ma. may be employed. Electrolysis for Warts. I'edunculated warts are treated by thrusting the negative 1 needle through the wart at a distance from the skin. A current of 2 to 4 ma. is allowed to flow for perhaps two to five minutes, until the wart has seemed to become blanched and looks like an herpetic bulla. This is rather painful, and it is better to use ethyl chlorid as an anesthetic. A steel needle can be used perfectly well. The same method may be used even if the wart is sessile. The author's patients greatly prefer the high-frequency spark. Electrolysis for Nasal Polypi. Negative monopolar or bipolar electrolysis may be applied with a current of about 20 ma. Electrolysis for Ozena. This must be done under local anes- thesia. A pure copper needle connected with positive pole is thrust into the middle turbinated bone, and a steel needle connected with the negative pole is thrust into the inferior turbinated bone. The needles should be about J T inch in diameter, and should penetrate about 1 inch of tissue. A current of from 10 to 15 ma. is gradually turned on, and allowed to flow for about ten minutes. Ir is then gradually turned off and reversed for a short time in order to loosen the positive needle. Electrolysis for Nasal Deviations and Spurs. --Bipolar galvano- puncture of the convex surface with a current of about 20 ma. for ten minutes is very effect ive. Electrolysis for Dilated Blood-vessels in the Skin of the Nose. This condition requires manv separate 1 gal van< ipunct ures of 1 he different blood-vessels at a considerable number of sessions. The treatment of a case may extend over as much as a year. Strikingly good results are often obt ained. Electrolysis in Vegetative Conjunctivitis or Spring Catarrh. Cocain and adrenalin are 1 necessary to secure complete 1 local anesthesia, and it' the' patie-nt is restle>ss, perhaps a general anesthetic will be 1 re- quired. The indifferent electrode (positive 1 , usually, but it makes little difference) is applied to the- foreliead or cheek. The eithe-r electrode' is a platinum needle- which is thrust into the different vegetations as close- 420 MF.DH'AL KLKCTKiriTY AND K< )NTGEN KAYS to their base as possible, and parallel with the surface of the conjunctiva. I'oiblv several mav be t rail-fixed at the same time. Flat vegetations are treated hv .-cariticat :< n\ \\ith i he same needle held perpendicular to the surface. A current of from '_' lo ^ ma. is used -not more than ^ ma. if cocain alone is used. Stronger currents cause pain and lacrimation. 1'aii-ier has u-ed 'his technic successfully. Electrolysis in Macroglossia. When this is due to tin' presence of lymphat ic cysts in t he >ul>st ance of the tongue, repealed bipolar elect ro- lysis under ;in anesthetic will effect a cure. The technic is the same as for aii^ioma cavenn >sa (p. 4 Hi). Electrolysis in diseases of the Vulva. Vegetations may be treated bv u'alvaiiopunct lire, bipolar or monopolar, and with a current o ! a b o u I .") m : i . ( 'hronic folliculit is vulva- may be t reated by positive ;alvanopuncture with imicii the same technic that is used for hypertriehosis (p. 414\ A current of '_' to ~> ma. is ap]>lied for five to twentv seconds. Electrolysis in Urethral Stricture, hurt's nnttmil of linear dctro- ' t *i.- by means of a ne^at ive electrode shaped very much like a uret hro- tome. and ad inu somewhat like the blade of a jralvanocautery. is generally regarded as dangerous and undesirable. A current of from lo to ">() ma. i- used. The indifferent electrode is placed upon the abdomen. A ' it'nni n'* i m tin a I nf a /'-, /In r t Ii rfrn! '/.-! * is safe and effect ive. and is one ol the n lei hod- o] choice. The ne^at ive elect rode is t lie act ive one. and coiisi-t- di' one of Xewman'- olivary urethra! bougies, the next size larger i lian t he smallest st rid ure. \\'hile t he elect rode is pressed lightly airain-i i he strict un 1 , a dirreiit ol trom '> to III ma. is gradually turned on just enough to cause a sensa! ion of \varmth aiul prickling. About twenty minutes application mav be required, and then this strictur<' be found passable by a larger olivary <'ledrode \\hich may be Used to t re;ii allot h<'l' larger strict Ul'<-. The iiulif'l'erent electrode is held on t he abdomen. Ton UTeat an effect is not soliuht at each session perhaps rease ol onl\ one or t wo numbers ol i he Fr<-nch scale in tlu- dia m- ei rr of each si rict ui'e. The t reat nients are u'lven at intervals of a \v<-<-k ni ' -. I i. .;: ' a MI in bv ordinary sound- is u-ei] m coimedion with eel |-i ii vi K- ! rea I HK'IIt. ' - ,1 n .in is tli<- name niven to a HH'thod in which me- ' it ion i- i he principal fact or. t hoimh t he dilat inii' sound also I ol tieuative eledricity. The dilatation may be >-lmr. : t roii ' i lira 1 sound \\ hich is la ri;e enough to pass I hrouuh t he lie slretchini;. and allouinu a current of from ~) to .'!() . to lif i loi ' vi in in ul i 1 .- or 1< -.-. The t real n lent s are L:I veil once a . ' . I IH lln i t'fi I'enl e|ed rode 1- ;i la I'll e one placed over | he abdomen. \ ii .' ' ' portion oi the metallic sound is insulated bv varni-h. ' current and the length ol lime for which it is applied i ' n laiion In ihe amount ol surface provided for t he contact. I in' proper i|Ualitit\ ot electricitv for each sijiiare cell* r ' ' : ric ci inl ad i~ about ,'',, cimlomb. or t he amount of po"'cil i.\ ;i current \ '_' ma. in fi\'e niinuti-s. ('alculat- i-'-d i el | sinlace in contact \\ il h t h<' uret hral mucous l:;e",b ' - |)l\'ini; the number o| sijllare centimeters bv '_'. : ol iiiilliainperes >*\ current which -hoiild be applied IONIC MEDICATION BY ELECTROLYSIS 421 for five minutes. This will be from 5 to '>() ma., depending upon the si/e of the sound ;ind the length exposed. The rapid ///clhod of electrolytic dilatation uses the same strength of current, hut a sound ahout five numbers (French) larger than the si/e of the stricture. Firm pressure is applied, and the sound passes through the stricture in a few minutes. Two or three different sixes are used at each session, and the treatments are given once a week. Electrolysis for Esophageal Stricture. /'W/'.s im-tliod of linear electrolysis is dangerous because of risk of injury to neighboring organs. Circular <'lrctrolt/*it< is perfectly safe, and is performed witli an olivary metallic electrode adjusted upon a flexible stem, which extends '2 or )> inches beyond the elect rode, and which contains an insulated wire. The whole forms an olivary esophagcal bougie. This is connected with the negative pole, while the indifferent positive electrode may be held in the patient's hand. A current of 4 or 5 ma. should be gradually turned on while the olivary bougie is pressed gently against the face of the stricture, and in a few minutes the olivary bougie, which should be the smallest one which would not pass the stricture, now goes through readily. Sometimes the next higher number also may be made to penetrate freely at the same seance. Treatments should be given about once a week, and the method is not applicable to obstruction from pressure, as by tumors and aneurysms. Electrolysis in Stricture of the Lacrimal Duct. A Bowman's sound, insulated by varnish except at its extremity, is connected with the negative pole, while a positive electrode is held in the hand. A current of about o to 4 ma. is applied for three minutes once a week. EXAMPLES OF GALVANIC, FARADIC, AND SINUSOIDAL ELECTROTHERAPY THERAPEUTIC EFFECTS OF OALVANIC. FARADIC, AND SINUSOIDAL CURRENTS.' I | ( 'athodal closure. Alternating galvanic currents with or (ialvanism. -j without condensers. Prolonged cathodal application (catelee- I trotonusj. f Successive discharges of the induced break current. Faradi.-m. ' Successive discharges of the primary cur- galvano- \ rent at the moment of opening of the faradism. ! circuit. j Sinusoidal current . Short waves from a small condenser, f Alternating galvanic currents with or without conden- sers. ( 'athodal closure. | Faradism, (-specially with a short secondary winding rhythmic or i.-olated waves, or sinusoidal). i ( ralvanofaradi.-m. I Same as for excitomotor , e.-pecially faradism, with a long i .-econdary winding and rapid interruption. i (ialvani-m. i Applied to glands which are sufficiently i Faradi-m. ) acce.-.-ible to receive a strong current. - | Faradi.-m with lonu secondary winding and applied by ;. ' . . nail 'nniliitliiit/ ir- ' metal brush. nr Jlnxinu I (lalvanofaradism applied by metal brush. Faradi.-m with -hort .-i-condary winding. A -ee<>ndar\ effect from va-oconstrict ive applications. Faradi-rn with lonu .-econdary winding. Triple phar-e or .-inu.-oidal currents in hydro-electric bath. I ie\'ul.-i\-e and va.-odilat ive a ppl i cat ions. Heat applied in various ways. Compre.-sed air-douche 'lull x. I heated bv electricity. I ( ialvani-m. I ' ialvalil-m \\lth iDtn/ation l< itit iphoresis. i 1 1 \ 'drnfaradic or h\drosinus- i oidal bath-. Hhythlnic general faradl/.at ic >n. ( icneral galvanix.atii.il. ! I vdniL'alvatiic bath.-. ) Cerebral. Mod . \! !.-l,:id','- table, Le- App GALVANIC, FARADIC, AND SINUSOIDAL ELECTROTHERAPY 42.3 Stimulating the natural ( means of defense of the I Hydrogalvanofaradic and hydrosinusoidal baths. organism ( f Galvanism (prolonged anodal application). Galvanism (Leduc currents). Hydrogalvanic baths (prolonged). Hydrogalvanic enemata, etc. Xcdatirc or calmative, inhihi- Undulatory faradization with wet electrodes. , . .. Monodic faradization (Stas). five, analgesic, or anti- sinusoidal faradization. ' 1 Secondary effect of revulsive applications. Variations of an electromagnetic field. Douche of air heated by electricity. | Quinin. Radium, etc. f Hydrosinusoidal baths in insomnia due to circulatory j disorders. ( Leduc currents (experimentally). r , j Anodal galvanism (by electrolysis). I Heat produced by electric means. f Prolonged anodal galvanism. 1 , / j Iontophoresis (copper, zinc, silver, etc.) by electrodes, wet with a solution of salts of these metals or by elec- { trodes of the metals themselves. Destructive of abnormal (is- ( Electrochemical or electrolytic. sues.. 1 T-i ti ' Galvanocauterv. Douche of air 1 Electrothermic. - h(?atp(l Vfiry ^ ot hy eloctrioitv Not included in this list, but considered in other sections of the book, are the stimulating effects of the static electricity, high-frequency cur- rents, electric light, and electric heat; also the excitomotor effects of static disruptive applications and static wave currents and undulatory dis- charges of high-frequency currents; also the extitosensitive effect of high- frequency sparks, which are preferable to static sparks for this pur- pose, and the diaphoretic effect of electric-light baths and dark heat baths (Dowsing method); the revulsive effects, etc., of static sparks, high-frequency currents, electric light, electric heat, diathermy by high- frequency currents; the vasoconstrictive effect of high-frequency reso- nator sparks and energetic efrluviation by high-frequency or static electricity; the vasodilative and hypotensive effect of high-frequency cur- rents, and the electric arc bath and other luminous heat baths: the the resoh'/ny, etc., effect of static wave currents, high-frequency cur- rents from vacuum electrodes, electric heat and light locally and as a bath, diathermy by high-frequency currents, Hontgen rays; the sclero- li/tic effect of electric light and diathermy by high-frequency currents; the excito nutritive, etc., effect of convective and conductive static ap- plications. autocondensation and autoconduction by high-frequency currents, Tcsla undulatory high-frequency currents, rhythmic effluve with Tesla-Thomson high-frequency apparatus, general electric-light bath, inhalations of ionized air; also stimulating the means of defense by high- frequency autocondensation and autoconduction. conductive and con- vective l. I. j ( 'uralile central paralyses. -, Curable peripheral paralyse.- and pare-es. ( Atony or myasthenia of stri|>ed and un-tnped muscles, ('uralile central paralyse. ; of sensation and hyperes- nnil < .rcilu- thesia and anesthesia. ] ('uralile peripheral paralyses of sen-ation and hyper- csthesia and anesthesia. ", . . Lacteal, seminal, etc., hyposecretion. I'd . . Kr\ thema. pruritus, etc. Vu.tinliliitirt K.-pecially in cases of hiiih arterial tension. I Inflammations in the static of resolution. tit / 'ilxn'i , tit rti'iittr*. t'lmiiti r- ' i - 11 i i -vi , Arthritis, especially blennorrhaiiic, metntis. Muco- illirea. j Hysteria of hyperexcitable type. f Neuralgia- produced by curable lesions. i Neuralgia.- oi' ;, toxic infection of dy-cra-ic oriirm. I lypersthenic dy-pep-ia. jia.-traljiia with hyperchlorhy- - . \ 1 1 <> i 1 1 1 1 1 a . I Nevus. j Tuberculi i-j- ( if a -Ii >w type. ' Art hrit ic ti ixemia. I 1 nfeci ion and ailti i-inlt >xicat it in. i \ 'arii in- dermati i-e-. i \Vnuiids. illcerat j, in-., etc. ) Trail mat ic LTaimrene. Diabetic L'aliurene I LupU-. etc. ( \dcniti- < ilandular t iitin ir-. I I ibromata and other neojil Gonorrhea! Rheumatism and Galvanic Currents. IVillinkin 1 cured a ' n| Klfiiiitii ' arthiitis of the \\TI-I 1>\' hea\'\' galvanic currents. '' '!-' \\.-i- at a tno-1 acute -taire, the \vri-t iiie;i-ui'iiiL; '2 inehe- more I '. . ' : i d' -ocii'ti'-. i rain e i i - ratin . .linn I'.io.'i (JALVAMC, FAHADIC, AND SINUSOIDAL KLK( TROTH KKAI'Y 425 in circumference than the other, and being stiff and painful. It had begun to be painful five days previously. Kach elect rode consisted of a sheet of metal 7 by 10 inches in size, with a very thick layer of wet ab- sorbent cotton. The negative electrode covered the hand, wrist, and three-quarters of the forearm while the patient was seated upon the positive electrode. A current of 1'JO ma. was applied for fifteen min- utes each day, and was followed by immediate relief and a permanent cure in four or five days. Delherm's method is to apply a continuous current of GO to 100 ma. for from thirty to sixty minutes. Large electrodes are placed at the two sides of the joint. It should be commenced at the beginning in the acute inflammatory febrile stage. There is relief from the very start. The pain, fever, and swelling disappear. Ankylosis is prevented when the treatment is begun at this early stage. At later stages the treat- ment is not quite so effective, but still does a great deal of good. Heavy Galvanic Currents in Acute Gout and Rheumatism. A cur- rent of 110 ma. may be applied for twenty minutes from a large posi- tive electrode on the dorsum and a large negative electrode on the sole of the foot. A five-minute application of sinusoidal currents of a strength of 15 ma. is a desirable termination to the treatment. Billin- kin 1 reports the curt 1 of such an attack in two treatments. A current of 50 to 80 ma. from two large electrodes applied to the knee in a case of acute rheumatism of that joint effected a cure in three or four days. Electromechanotherapy (p. 483) is of value in some cases of chronic articular rheumatism, because of the increased respiratory exchanges produced by electric exercise. '- Faradic Currents in Hydrarthrosis of the Knee. / J /'/m/'.s tnctlmd is to stimulate all the different muscles of the thigh in succession, keeping one electrode at the upper and outer part of the thigh, and applying the other to the different motor points in succession for twenty seconds. This part of the treatment is very painful. The electrodes are then applied at either side of the patella for five minutes. The claim is made that a cure is effected in a few days without immobiliza- tion, and that there is immediate benefit. The objection is the pain. Danger of Galvanic Currents in Tubercular Arthritis. The current is to be cautiously applied in t ubercular art hrit is and in a patient who has tuberculosis of any other organ. Faradic and Galvanic Currents for Hydrarthrosis. Strong galvanic currents applied from large electrodes covering both sides of the joint have been considered the method of choice, but the author has used the milder high-frequency currents with success (p. 583). A faradic coil with fine wire and rapid interruptions, and as strong a current as can be tolerated, may be used in the treatment of hydrar- throsis. This, however, is a painful method. Vibration is useful for stiffness of the fingers after injuries such as ('olles' fracture and dislocation of the shoulder. 3 Rheumatoid Arthritis.- Faradization of the muscles about a oint 42) MEDICAL ELECTRICITY AND RONTGEN RAYS and :rnjiliH' Disinj'tctanl . . ELECTROTHERAPEITIC INDICATIONS IN SKIN DISEASES. (Virgilio Machado's Classification.) Stimulating . . Falling of the hair, alopecia, atonic ulcers, sclcroderma. s - , - i Pruriginous dermatoses (lichen, prurigo. eczema, herpes ( zoster. \'a*oci>n*trictin Krythemata. ting tht ahanr^ttnn nf Kdemata following contusions. txudah* ' ( i Dermatoses due to general nutritive disturbance. t Localized trophoneurotic dermatoses. . .Septic wounds, ulcers. | Elephantiasis, certain varieties of eczema, mr-vi, El> rlrnl ijttc. . . angiomata. hypertrichosis. alopecia areata, sclero- ( derma, acne. JGalvanocautery. (Lupus, certain varieties of High-frequency sparks j epitheliomata, phagede- Static s{>arks. ] nic ulcers, Rontgen-ray ulcers. 1 [ Compressed air heated by electricity. Ulcers. ( Lupus, especially vulearis or tubercular, certain hi' ctroitiiototiK rn in/.- i i- ' c i i j- I epitheliomata; many superficial skin diseases. ( Epitheliomata, especially superficial, sarcoma, rodent ulcer, lupus.- elephantiasis, mycosis fungoides. Kerion c^l-i, acne rosacea, acne vulgaris. acne keloid. sycosis frambesiformis. Tinea favosa. onychomycosis favosa, tricho- phytina, lichen simplex, lichen ruber. and acuminatus. SVCOMS. furunculosis nuchae. microsporia. hypertricliosis. chronic eczema. seborrheic eczema, alopecia areata, nevus vas- culans planu.s. Ichthyosis, pemphigus vege- tans. psoriasis, neurodermatoses, scleroderma. |>ruritus. herpes zoster, herpes tonsurans, |)rurigo. trichorrhexis nodosa, scrofuloderma, hyperidrosis. verruca, verruca necrogenica cutaneous tuberculosis i. I '!<* rtititinx (xtiliri/lic nr zini- iontofthorcaix}. \ Secondary infections from eczema and other secreting der- matoses. Kpithelioma. acne, furuncle, fi.-tula. carbuncle izinc ionto- phore-i-; anode of amalgamated zinc "requires a general anesthetic and has no advantage over .c-ray"). Falling of hair, sycosis, tinea, fistula'. \ - erruca i copper or mai:ne-ium iontophoresis i. N'evus, small epitlielioma, lujius. leukojilasia. acne rosacea. KiTato-l.-, acne, ec/.eina of a lichen type. I Kdoid. psoriasis, verruca. Electricity in Skin Diseases.- Kflluve- from static or hiy local galvanic i-urreiits. | -or -cirri idi'i'ina eirciiniscripia. two electrodes are at ojtposite " Macharlo - !':-. m pi Tat I Vi s- I "In lup'i- an' I other -km di-ea-e-. phot ot hera py i- often associated with tht r-ray- and l)oth are -ometimes aided liv -> -n-iljih/at ion of the -kin with eosin or . n -cin. GALVANIC, FARADIC, AND SINUSOIDAL ELECTROTHERAPY 427 sides of the area and a current of 8 ma. is applied for twenty-five minutes. Chronic pruriginous eczema has been successfully treated by central galvanization, and so has herpes zoster. The same method of treat- ment of the spinal cord by either galvanic or faradic currents has given successful results in vitiligo, ichtkyosis, ecthyma, pemphigus, cutaneous gangrene, prurigo, eczema, urticaria, and lichen, all these diseases being possibly of nervous origin. Hydro-electric baths are excellent in all these cases. The galvanic current locally relieves the itching of lichen ruber. Perforating ulcer of the foot has been cured by faradization of the posterior tibial nerve, high-frequency currents (p. 583) also being useful, and erythromelalgia and symmetric gangrene have been successfully treated by the local application of galvanic currents. Electrolysis in its applications to cutaneous lesions is referred to elsewhere (p. 419). The resolving effect of the galvanic current makes heavy currents of this kind valuable in keloid, 'mycosis fungoides, elephantiasis, and in cicatrices following burns. Alopecia is treated by faradization of the scalp. The author has had excellent results from the application of sponge electrodes, but has less confidence in the application of electric brushes and combs. The latter have their use, btit it seems as if the combing and brushing could be better done separately from the application of the electric currents, and as if a sufficient strength of the latter to do much good is disa- greeable or painful if applied by brushes or combs. Static electricit]i i- s valuable in skin diseases, especially on account of the anesthetic effect of the static breeze or effluve upon such lesions as pruritus, eczema, and lichen. The general effect of a static bath is also excellent in these cases. The same effluves are valuable in frost- bite, radiodermatitis, psoriasis, impetigo, acne, lupus cri/thematodes, and furunculosis. Static sparks give good results in keloid and other localized sclcro- dertna and morphea. Static l>athx and effluves and sparks have been recommended for alopecia, but the author's experience with static electricity has led. him to regard it as an application which is rather apt to cause the hair to fall out. The number of patients who have complained of this symptom in the course of a series of treatments by the static bath with an efHuve applied over the head makes it seem as if it were not a mere coincidence. A number of static sparks applied to the scalp seem a better method for treating alopecia than several minutes' application of the static breeze. Varicose ulcers and sluggish wounds may be stimulated by the application of static sparks, and the wound left after curettage for lupus may receive static sparks as a germicide 1 . Pruritus Vulvoc. The best methods of treatment are by the .r-ray and radium. Other valuable methods are the incandescent electric-light and the static breeze. High-frequency Currents in Skin Diseases. This is described on page (521 . Herpes Zoxter Treatment bu Galvanic Currents at an Early Stage. At an acute stage treatment may be applied by a positive electrode MEDICAL ELECTRICITY AND RONTGEN KAYS measuring '.' by 1M cm.. applied alon to >> ma. is applied for twenty-five or thirty minutes every other day. The disease is sometimes cured in forty-eight hours, and without leaving any subsequent neuralgia. A of*! "/' h, r/i< * ;.x7, r occurrim: durum a course of treatments by hi::h-frequency currents was cured by Petit 1 by the application of heavy galvanic currents. A positive electrode measuring \.~> by Hi cm. cov- ered the posterior roots of the nerves in question, while a negative electrode of the same si/e covered the side of the chest and the three Lrroups of vesicles. A current of from (50 to 70 ma. was gradually turned on. allowed to flow for ten or thirteen minutes, and gradually turned off. There was some relief from pain immediately, and a cure was effected, by ei-ht daily treatments. }' a I'n >icl> N nut! Anthra.r Tnattfl In/ (fah'dnic Current*.-- Negative Lialvaii.ipunct ure wit h a current of ."> or 10 ma. for live minutes is effective. I* u-ua!ly requires the use of ethyl chlorid for anesthesia. If a '/.'me needle is used, the positive wire should be connected with it to secure lenelil i if /.me mni/at ion. X-niij in SL'in llixcdxi *. This is of the greatest importance, and is referred to on p. tiL'l . Phototherapy, including treatment by the ultraviolet rays, is in- valuable. Obesity.--- //'//m//// I nt< rri//>t<(! (inlr/mic Cum nl*. These currents have a powerful effect in slowing the development of growing and caus- ing emaciation in adult animals. It may be that they will be found Useful in the treatment of obesity. Si in ultii at mis I'"(tr(iasse> to the metal ball used a> the vibrator, and the latter i- covered with damp cloth. The current should be strong eiKiujili to tetaiii/e the muscles. The coil ha- coarse wire. Hirr/i/nn"* Tr< tiffin >it nf ()h< *ifi/.-- A faradic coil, with a ratio of about 1 in the primary to about ',] in the second. :r\', i- used, and the primary current is considerable, -ay l", anijx'res ol '_' 1 volts. The rate "f interruption i- about MO per second. This curp nt i- rhythmically applied 100 time- a minute by means of a metronome and after half the turn it i- turned oil and reversed. Three electrode- pa-- from one pole i'' the back and the uiidersurfaces of the thiti'h-. From the other pole wire- pas.- to a number of rheostats, and through them to different large semicyliiidric electrodes back of the calves, from .if the thighs, abdomen, and arm- twelve in all . These are held in place by rubber bracelets or l'\ -and-bati- all the way up to a total weiuht of _'()(( pounds. The cur- reni den-ii\ i- only .ol ma. per -quare centimeter. A hot wire mil- liamperemeter -liows a total current of '_'.") to MO ma. for an ordinary -''Hi' tat and mu-cular \\ < 'men !'e(|Uii - mii 70 or S ma . Treat men t- la-t from twenty to forty-five minute- daily. I)amp lo\\'els cover the elect rode- and the patient has on a linht dres-intr-^'oxvn. The liest and ' : p ' i H-nt rate of red net ion i- 2 1 or M 1 . pound- a week. Cififtulic l.li r/, ,-jitii,n irith Ilinni (iulrtinic ( ' urrt lit* /n Olx.^ili/.- This application (,;,. been found to pfodtlce a loss of weight, u'hich i- GALVANIC, FARADIC, AND SINUSOIDAL ELECTROTHERAPY 429 so great as to make it a successful means for treating obesity, and to make it undesirable in cases of malnutrition, debility, or cachexia. The current must be applied in such a way as to avoid shocks or burns. Raynaud's Disease. Treatment !>;/ (!iiocks from a faradic coil with coarse wire and a strong enough current to produce strong muscular contractions are applied at the rate of one to five per second. Daily applications of about live minutes are made at tirst. but later they need not be so frequent. S/>ns>n of tin AV// //<(// Sj>liinct< r of (In I'rttlira. This may be treated by a rectal electrode, usini;' a faradic current with very slow interrup- tions, coarse wire, and a very weak cui'rent: or the positive 1 galvanic current or hidi-frequency currents. Static electricity is useful in neur- ast lieiuc cases. Spasmodic Stricture of the Esophagus. This condition is treated by faradization applied bv means of an esophaireal elect rode, and one at some indifferent place. A series of currents may be applied to pro- duce million- of deglutition, and in this way to relax spasm. A coarse wire coil and slow interruptions are used with a modi-rate strength of current . Percutaneous Electrization in Gastric Diseases. A considerable number of observers doubt the efficiency of intraji'astric electrization, and it is certain! v difficult to apply, us well as disagreeable to t he patient. By percutaneous electrization is meant the influence upon the stomach from electric applications made to the skin cvei that ortran. SirrtfiH-'/ function* are best influenced by faradization. One elec- trode i- -labile at some indifferent point, and the other is labile over the gastric area. A fine wire coil and rapid interruptions are used with the strength of cui'rent which proves most agreeable to the individual pat lent. Motor function* are influenced by ^alvanofaradizat ion. and the best wav of appivinji it i- bv means of t he rhythmic rheostat and pole changer described on p. ISH. (.^uite laril'e electrodes arc used. One covers the LTa>tric area, and the other is between the shoulder-blades. A galvanic current gradual 1\~ lie-ins to flow in one direct ion, and at t a ins a st ren.irth n! _'i i ma., and then gradually diminishes to zero, and gradually attains a -tren^th of I'D ma. in the opposite direction. The same changes take plac 1 in t he farad ic current . but the change in si remit h is more im port ant ':. .:. the chatme m polarity. The faradic coil should have coarse wire iiid -lo\\ vibrations, and the strength of the current should be such as to ran->- marked contraction of the abdominal muscles at the height of e of current. The oscillations of the current take place at the ra 1 '- o! from I went y to sixt v a minute, depending upon t he sens at ions of i ii ni . M''' 'ions are al-o favorably influenced bv the static m- , nt. The external armature of the Leyden jar at the posi- |e(l. while the oilier is connected with a metallic !i-ct [-1 ide ajipln ; to t he skill of 1 he epiirast ric region. The pal lent is The -park rod- of the static machine are from '2 to (i i he machine i- regulated to produce seven or eiirht ,. I'ordier make- t he applicat ion to 1 hree principal points: e. a lit 1 le above i IK- umbilicus: _' a couple of inches ' ' hi - dlall line and a little above the level ol the limbiliclls : - 'he left anterior siiperioi -pine oi the ilium. Strong rciir, and the patient feels a shock at each spark LMUL: rod- ot the static machine. Tin- treatment ites. and i- L: veji evi ' da' n| i -vi -rv i >' her ' : .hi -iomach is cured m six \\ eek- 01 -< >. GALVANIC, FARADIC, AND SINUSOIDAL ELECTROTHERAPY 431 Sensory functions of the stomach arc favorably influenced by gal- vanic currents, and surprisingly heavy currents, 100 or 200 nut., have been recommended by sonic: authors. 1 Much weaker currents should generally be employed. The Influence of Intragaxtric Electrization. Freund'-' lias made a series of observations from which he concludes that no specific secretion is excited, but that a thin, more or less acid mucous secretion takes place. Atonic Dyspepsia. This may be treated by intragastric rhythmic galvanic currents or galvanofaradization. Galvanic Currents Applied to the Pneumogastric Nerve in Stomach Troubles. An electrode may be applied over each pneumo- gastric nerve at the base of the neck, and a current of o or 10 ma. is applied for five minutes, with occasional reversals. This may cause the disappearance of nausea, vomiting, and regurgitations in cases of dys- pepsia, with symptoms suggestive of cancer. Electricity for Habitual Constipation and Membranous Colitis. Slight cases yield to the static bath, static breeze, or static sparks in the iliac fossa'. The sparks are for the atonic, the breeze for the spasmodic, variety. (Irave cases of atonic constipation may be treated by faradiza- tion, rhythmically reversed galvanic currents, or the Morton wave cur- rent. These may be applied to the skin or to the skin and intestine. Grave cases of spasmodic constipation and enterocolitis are greatly benefited by faradogalvanization. The galvanic current is about 100 ma., and is not interrupted or increased, the faradic current being a mild one from a coil of fine wire. One very large electrode is over the abdomen, and another is over the back. Rectal vibration either internal or external may be used for relaxing sphincters. Fine long wire faradic coil stimulates peristalsis. Coarse faradic coil does not ( De Kraft). Faradization over course of the colon produces prompt evacuation of the bowels. 3 Nervous state with fecal retention but daily movements. To ma. ordinary galvanic current may be applied for one to two and a half hours at first t. i. d., then b. i. d., then once a day. Of course it must be applied and turned off gradually. Intestinal stasis is benefited by the slow surging galvanic current for twenty minutes followed by vibration for two minutes. 4 For an effect on the liver one may use the slow sinusoidal current with a sand-bag over the electrode if the static wave current is not avail- able. The same current is used for atonic constipation, with the pos- terior pad over the first, second, and third lumbar vertebrae, and for spastic over the eighth to eleventh dorsal (Morse, see page 430"). For constipation; to strengthen abdominal muscles, fairly large sized electrode on the back over spinal nerve supply and smaller elec- 1 Ruhinovici, Those do Paris, 1907. -' Arch. f. Patliol. a. Physiol., May. 190."). 3 Livingstone, Amor. .Jour. Electrotherapy and Radiology, vol. xxxvi, Xo. 1, January, 191S, p. 20. 'Martin, Amor. Jour. Electrotherapy and Radiology, vol. xxxvi, Xo. 9. Sep- tember, 191S, p. 21)."). MKD1CAI. KI-KCTKinTY AND RONTUEN KAYS trodes in front over the ascending and descending colon using a bifur- cated cord or changing the position of the electrodes apply surging electric impulses Mor-'\ see paue 439\ The sigmoid, either for impact ion or gaseous distent ion, is treated by a curved rectal electrode passed well up into sigmoid and a smaller sur- face electrode over it. A heavy long contractile effect having not over 2(1 suruinu wave impulses per minute (Morse, see page 439). Postoperative areas, muscles, and nerves severed or weakened by lonu-continued use of abdominal belts are treated by Morse surging current -. ! Massev -ays that the currents from Morse's apparatus, like all other small induction currents (faradic, Malic wave), are all probably an ex- ceedingly -mall fraction of a second in their rise and duration. These do not reach deep-seated orgau> in sufficient volume to do the work of producing contraction in deep-seated involuntary muscles. Massev uses kaolin electrodes 1 inch thick with a backing of sheet metal 2 inches -mallei- all around. A slow sinusoidal current of 200 ma. on a pad the sixe of the crown of a man's head anteriorly and considerably larger In-low the shoulders posteriorly is not too much current in many cases of lariie abdomens or where there is much fat. This is applied for twenty to thirty minutes, avoiding too much heat by having alter- nat ion- considerably more than 12 to the minute, 1") is right, or oO waves. The current he uses is t he same as t he aut hor's (see page 4Mi . His be- irmnini: do-e i- .">() ma. for thin persons. Contraindication to galvanic current is found in malignant conditions. l)inrrhi a yields to application- of ulass vacuum electrodes from ! he i ludin resonator applied over the Mirface of the abdomen. A'.'-.',/.';,;-',,,, i- also excellent: a very la rue electrode covers the abdomen. :: | i( l another the lumbar reuion. '1 he current is from the I ilinu; di i he abdominal muscles, not a tetanic con t ract ion. A rii.--i nf . -, , rli !,,,',< rufiti* mnl (/'/*i titi i'-i successfullv treated bv ^h-fr<'i[Uency current- irom \\-ICUUMI electrodes is de- d on p. I'do. /.'/,,'> 1i,li*tintil J)tiiirJn'H.- The -troimcr currents are useful in in- ' til li-truction and occlu-ion and in lead colic. They are regarded ru'ency treatment, intended to provoke a mox'eitKMit of the bowel- at any co-t . T!ie\- are not -uitable for repeated application y v/Mijld pi'iHJuee -pa-modic constipation. .' ent i- a sofi -ruliber rectal tube, \\-hich covers transmits the liquid. N'n pan of the nx'tal ' i-t ih the fle-h. I-'rom 1 in 1 '. pint- of salt water V ectrodc measuring abmit ~> by 'i inches is placed i-n, : ' '''!.- :\ nt current of about .'in or H > ma. is , . Then i he current i.- -uddenl v revj-rsed. and 1 1 ilirect ion In] one or i uo nnnut es. Tin 'se o! con-taut flow al'e kept up foi ' went v or t hirt y iii ': av tin n try to ha\'e a moveiiK-nt. This mav , bin the etlect i- -itmetime- delaved for -e\'eral KA1.VAXIC, KAUADIC, AM) SINTSOIDAL KLH( 'TK< (THKKAI'Y present in the rectum, hut failing to stimulate evacuation is successfully treated by electric douches with the external electrode sometimes over the sigmoid flexure and sometimes over the cecum. The current flows in the same direction for ten minutes before being gradually reversed. The Apostoli Method for Uterine Fibromyoma. The author of the method called it elect rochemic cauterization of the mucous membrane, and the results lie obtained were the production of a new and healthy mucous membrane, with a greatly reduced tendency to hemorrhage and often a reduction in the size of the fibroid tumor. He irave the present writer an opportunity to examine some of his cases in Paris in IS'.H. The tumors had become much smaller, and there was a symptomatic cure. Complete disappearance of uterine fibromyomata under this treatment occurs in only about 10 per cent, of the cases I rented. A galvanic current of (it) or 7(1 ma. is usually employed, but in certain cases as weak as 'JO or .'>() ma. or as strong a current as 100 ma. n!' more is used. The act ive positive electrode lias a platinum or carbon olivary tip and an insulated stem. It is applied successively to all parts of the mucous membrane of the body of the uterus, but the internal os. the cervix, and the external os are protected to avoid the risk of cica- tricial contraction. The indifferent negative electrode is usually a large (lay or kaolin electrode placed over the abdomen. The application lasts about five minutes. Besides the electrolysis of the mucous membrane there is a trophic effect upon the Tumor tending to cause a return to normal conditions. The latter effect is best obtained in intramural and submucous fibromyomata. Sub peritoneal tumors are often very little affected by the current from an hit ra-uterine electrode, (lalvano- puncture is suitable for some of these which are suprapubic or which can be reached through Douglas's cul-de-sac. Care is taken in each case to avoid coils of intestine and to apply the current exclusively in the sub- stance of the uterus. The needles are to be insulated where they pierce the vagina or skin and the parietal and visceral peritoneum. The Final Rtxnltx of l/n Electric Tnnh/unt f I'tcri-nc Fihmn/ti. Massey 1 has traced the results for three years after treatment in 101 cases, among them were IS cases in which the tumor had disappeared ; '_'(') cases were failures. Interstitial hemorrhagic fibroids are the most favorable, and the submucous variety also yield.- good results. The subserous variety, especially if pedunculated. are less certain. Fibroids complicated by pyosalpinx and other stippurative or inflammatory conditions are not entirely safe to treat in this way. At the present time- the Apostoli method is considered less desirable than treatment by radium or the Kbntgen rays. Electricity in Sterility Due to Atrophy or Imperfect Development of the Uterus. Rhythmic unduiatory galvanic currents with alternations, applied from an abdominal electrode and a vaginal or r.n int ra-utenne electrode, and a maximum strength of 1") ma., are excellent. The author has had success also with high-frequency currents applied from a vaginal vacuum electrode with a double stem, which insulated all but the portion in contact with the cervix and Douglas' culdesac. Persistent purulent catarrh of the uterus is about the only in- . Assoc., Mav L'l, 1904. l->l MKDICAL KLKCTHIcrrV AM) KO.NTGKX HAYS dication for an intra-uterine electrode. For that Massey uses mercuric ca'aphoivsis with a moderate current. De Watteville or Faradogalvanic Currents for Menorrhagia and Enterocolitis. A positive electrode is placed over the lumbar region, and a la rue negative one over the abdomen. The- galvanic rheostat indicate- UK) ma., and the t'aradic current is from a coil of line wire. The application lasts a Unit ten minutes. Electric Treatment of Asthma. The positive electrode is the active one. and measures 'J'. inches in diameter. It is placed first on one side o:' tiie neck and then on the other: then at the side of the trachea, and then at the lower attachment of the sternomastoid. Jt is moist- ened \\ith plain warm water. '1 he negative electrode is a larger one. and i- placed eit her at the nape of t lie neck or. in a case of tuberculous psi ido-aslhma. it may be placed over the upper part of the lung in of the chest. The strength of the curix nt is from 10 to 15 ma.. lay be rhythmically changed from xero up to this strength. This oscillation should take from five to six seconds. The treatments last from ten to fifteen minutes, and may be applied two or three times a Week. Expectorant Effect of Galvanic Currents. The negative elec- trode i- placed at the back of the neck, and the positive first on one side and then on the other, at the border of the scaleni: or the positive may be branched and lead to an electrode on each side of the neck. The current is to be '2 or '! ma. wit h one anode, or 4 or ^ ma. wit h a double anode, and is to be a constant current for about three minutes. Stembo' has found that this application will provoke cough and profuse expectoration where med ; "ines fail. He has used it successfully m bronchitis and bronchopneumonia. Ear Diseases. -Stimulation f tJn F/ici/il \(/-r< in f}/< K.vtrrnal .\ 'itl'tnT'i ('mnif for l)r/i Ol/lis Mi or I ma. with occa-ional change (iALVAXIC, FAUADK', AM) SINUSOIDAL KLKCTKOTHKKAI'Y 435 in direction, five 1 e>r te'ii minutes in acute cases e>r twenty minute's in chronic cases of otitis media. Acute pain is relieved in a few minute's. Functional e leaf ness of nervous exhaustion responds to two or three 1 ivat- ments plus a little 1 faraelism." Acute mastoiditis vanishes if treated early. The electrode is wet with j, 1 ,,, mercuric iodiel, 5 ma. are- applied over the 1 mastoid process for one-half to one 1 and one-half hours morning and ('veiling. In purulent otorrhea zinc ioeliel ioni/ation lessens the 1 leiikoe'ytes and lymphocyte's. Alum (2 per cent.) is used for ioni/ation in relaxation of the tympanum. Arsenic ionization is beneficial for tuberculous middle-ear trouble 1 . For aural vertigo due to labyrinthine 1 loss of couple, iodin ionizations are- used, the 1 positive pad being behind the 1 mastoid, 5 ma. is applied for a half-hour every other day for one or two wevks. For pain in the 1 mastoid, cocain or morphin ionization is used. A case of goiter which refuses x-ray or radium may be 1 treated by an aluminum anode x 1| inches, four thicknesses of lint, 5 per cent, zinc ioelid, 15 ma. for one hour. For ioni/ation of the' Kustachian tube use a cathe'teT closed at the 1 end but with lateral perforations for the last \ inch. The* external enel is joined to a fine 1 tube 1 holding potassium iodiel solution with a fine wire carrying 3 ma. current; five-minute seances being suitable for tinnitus. Prostatic hypertrophy may be treateel by ionization under a local anesthetic. Nerve 1 pain due 1 to dry middle-ear catarrh is treated by 250 watt carbon filament bulb over mastoid and Yates' static brush discharge 1 to both ears (Hirsh). The Yates Method of Treating Deafness (Herbert F. Pitcher). From the negative 1 pole of the static machine 1 the 1 ball spark electrode moiste'iied with warm water is pressed firmly against the 1 worst ear. From the 1 positive 1 pole a multiple point elect roele is held close 1 enough to the other ear (2 or 3 inches) to produce an efrluve. The discharging rods are widely separated; the strength of the current is regulated by the 1 speed of the 1 motor. 1 For de'afness Neiswanger use's a single' elect rode with terminals to insert in the canal of cae-h ear (Mclntosh Co. of Chicago), covered with cotton moist ene'd with a saline' solution, and through these the wave 1 current is applied. - Middle-ear disease has been treated by D'Arsonval and Oudin methods combincel (S. St. .John AYright :i ). An insulated wire 1 bare 1 at both tips touches the mouth of the 1 Kustachian tube and protrueles from the nostril, where it touches a glass vacuum electrode from the 1 Oudin resonator. The 1 operator holds an electrode from the D'Arsonval coil in his hand, of which e>ne finger te>uches the 1 mastoid process or the external auditory meat us. The 1 current is not to be strong enough to cause any sensation. Frontal sinus infe-ction is treated in the same' way, one 1 wire is in middle' mealus of the 1 nose 1 , external cord tip at fore- head. The 1 tear duct is treated through the inferior mealus; the anterior et humid cells through the middle mealus. the posterior through the superior meatus. The sphenoidal cells are treate-d through the middle or superior meatus, while the 1 other wire leads to a moist cle>1h at the rear of the vertex. 1 Amer. .lour. Klectrothorapv ami Radiology, vol. xxxvi, No. 9, 191 s, p. _>:,!. - Ibid.. Xo. 9, September, 191s. p. _>.":>. Ibid.. Xo. 9, September. 191s. p. 2.">7. i:'>i MKIMi Al. K!.K< TKK ITY AM) HO.VH , K.\ KAYS 'I'he fallopian tubes are treated first by a vacuum ( )udin electrode a- an antiseptic and a metal 1) Arson val electrode over the hypogas- trium for fifteen minutes, then int racervical glass vacuum electrode and I )'. \r-on val over fallopian tube seven minutes. For peri met rit is copper insulated rectal electrode: also for prostatitis and seminal vesiculitis, and some cases of appendicitis. (Jail-bladder covered by a metal plate touched by ( Midm vacuum electrode. D'ArsoilVtll electrode on the back. Samuel .1. Harris' reports success in the electric treatment of eye diseases. For ua lvalue and sinusoidal currents the indifferent elec- trode i- a Mor-e pad placed at the nape of the neck, or the patient's head may rest upon it. The active, usually the negative, electrode terminal*'.- in two eye cup- filled with absorbent cotton wet with a suit- able -olution and pressed against the closed eyelids. This techmc is with from _' to ."> ma. for ten minutes in the acute cases and from ~> to ID ma. for i ho-e ihat are chronic, lodid solu'ionsare most commonly employed when loni/ation is required. The li-i of lc-ions benefited includes: Ptosis: conical opacities: cornea! ulcers : irit i- in this use positive galvanism for its anodyne effect until the painful -taue has passed): glaucoma: cataract, spontaneous and traumatic: optic nerve atrophy; muscular imbalance; eye-strain. I- or pterygium the electrolytic needle is thrust into the apex of the iiro\\ i h and a current of 2 or o ma. is allowed to flow for al >out five minutes. Three or four days later the last of the growth is treated in the same way. Several treatments are required. The r-ray and high-frequency currents are used in scleritis. Phototherapy through glass, to arrest ultraviolet rays while allow- ing liii'ht and heat to pa-s. is used to produce hyperemia and increased nutrition of the lens in incipient cataract. Galvanofaradization in Lumbar Sprains.- A negative electrode mea-urinir '> by ."> inches is applied to the muscles of the lumbar region, and a -imilar one to the insertion of the glutei. 'I hf ualvanic current i- 10 or 12 ma., and the faradic coil with fine Fleet ric -timulation of the abdomen is useful in the treatment of ar- f '-rial hypert cnsion.- Sinusoidal Currents for Dyspepsia.- Two wet electrodes, ti by 4 inehc-. are fa-tened at eillier -ide of the uinliilicus and the sinusoidal 1 ' p. !.; |( i- applied for fifteen or twenty minutes. HYDRO-ELECTRIC BATHS - which -imply form the electrodes, as in the four-cell bath, ' oil!;, word at this place. The li(|iiid may be a very weak -odium chloiid with a -mall amount of glycerin added to p." 01 i if the -kin .it the surface of the liquid. If no such precaution : taken, a ring of redness i.- produced around the limb, iid liquid. It i- apparetitlv due to oxidation. i/.e bandage extending an inch or t \\'o above liquid v.ili al.-o prevent tlu- irritation. Baths "id principally as a very convenient means of GALVANIC, FAKADIC, AND SINI'SOIDAL KLKCTROTIIKKA PY 437 supplying a perfect contact over ;i large area for the transmission of rather heavy currents, hut not, as a rule, for the heaviest currents. B. Single large baths (Fig. 201 ) in which both the electrodes dip into the li(|uid and in \vhich the patient's body is immersed, cause the trans- mission of a part of the current through the patient, while about twice as large a part passes through the liquid from one pole to the other. The liquid may be plain warm water. The addition of a little sodium chlorid or sodium bicarbonate, or any other medicinal substance, in- creases the conductivity of the liquid and reduces the proportion of the current which passes through the patient. The electrodes had belter be flat pieces o r copper or carbon enclosed in a lattice work of china to 1 prevent contact with the patient. The tub may be made of wood, glass, or porcelain, an ordinary metal-lined tub being unsuitable. There should be no metal outlet pipe connected with the ground it should open in the air. The inlet pipes should not dip into the liquid. It- should be possible to place the different protected electrodes close to the nucha. one or both shoulders, one or both hips, one or both knees, or the feet . Several electrodes of different si/es and shapes will be found useful. The bath-tub may be made of perfectly enameled iron. There must be no bare spots of metal exposed to contact with the liquid: practically all the current would travel through the metal instead of the patient. A wooden or enameled iron bath-tub has one advantage over stone or porcelain. Tin 1 latter feels stone-cold to the patient wherever his flesh touches it. while the two former a-sume the temperature of the water. A General Bath Divided by a Diaphragm (Fig. 'J'l'Ji.- This is an expedient which is not apt to give much satisfaction. The idea is to have two portions of liquid separated bv a pa!'' it ion with a hole through which the patient's hodv passes, but around which the partition i- . hermetically scaled. Klectrodes dip into the two portions of liquid. and the entire Mrength of the current is supposed to pass through the patient 's bodv. T>S MKIHCAI. Kl.KCTHICITV AM) RON'TCKN" KAYS It is sometimes desirable for the patient to hold one electrode, which may he a metal handle, laid across the bath-tub, and upon which his hands m:'v re>t. 'I lie oilier elect rode, which may he single or multiple, dip- into tin- water. It may be placed near any part which it is desired e ] lecially 1 o affect. The switch-board for electric-bath currents should be so constructed that placing metal plugs in different holes will connect the cathode \\ith any or all of the different electrodes, and the same way for the anode. For instance, the negative wire may be connected with the rodes near both hips, and the positive wire with the bar electrode, on \\liich both hands rest, or the negative wire may be connected with a single large electrode near the feet, and the positive' with one near i lie shoulders. A shovel electrode with an insulated handle is useful for localizing t he current - Fig. 2 ( .)o). It is connected with one pole ol t he bat t (My and can be held in the water close to any part of the body, while the other electrode rests in >oine other part of the water. A niilliamperemeter is required to measure currents up to ;>()() ma. for mo-! ordinary purposes; and up to - amperes in a bipolar bath of tan-bark -olut ion and ot her medicinal >olut ions. The electric resistance ot t he-e solutions i- >o -mall that a much larger fraction of i he current will pa-- throuu'h ih" liquid, and a stronger total current is required in order to tran-mit the u-ual amount through the body of the patient. i doe- not applv. however, when the patient holds one electrode i- out "l the bath-tub. 'I hen all the current indicated bv the piTt-mel r| l p;i Ver>eS 1 lie pa I lent '.- bodv. Faradic or Induced Currents for Electric Baths. The ordinarv : i -a ' resist a nee lor I his work. o\\ ing to the 1 hoiisands through which the secondarv current must pass. I : .' in ' ,- coi;-M- ni a primary coil of coarse wire, with a vibi ' , , iluni interrupler. I he dischar.uc \\hich is sent 1 ' i i ' ol I he -a I ne ex l |-;i current l hat i- ut il i/.ed for li^'ht - L 1 ,: i'-t- ! elect n'cit v. Tin- is a current of self-induction in the GALVANIC, FAHADIC, AND SINUSOIDAL KI.K< TROTH KKAI'Y 4M ( . primary coil. There is no secondary coil. A battery of three or four wet or dry cells is sufficient for this purpose, or a suitable strength of current may be derived from the direct electric-light circuit. The ad- justment of the induced current is twofold: regulation of the number of turns utilized in the primary coil, and regulation of the position of the iron core. Drawing the latter out of the primary coil makes the induced current weaker, and alters its character, making it less harsh, just as in the case of a faradic coil. Intermittent Claudication. A case of this disease without any per- ceptible femoral pulse and long inability to walk was cured by \V. Kuhn. 1 The faradic current was applied to both legs by a four-cell bath. Currents Employed in General Hydro-electrotherapy. Galvanic and faradic currents are largely employed. Sinusoidal, undulatory, and triple-phased currents are especially effective. Undulatory Current*. These are unidirectional, and increase and diminish in a regular curve (Fig. 294), similar to portions of a tracing made by a sinusoidal current. The}' are used in the same periodicity and strength as the sinusoidal currents, whose effects are also very similar. Sinusoidal Currents. The name is derived from the sinusoidal curve formed by a graphic record of the current. This resembles a semicircle above the zero line continued in a semicircle below that line. The current, therefore, is an alternating one with a gradual change of strength and direction. In the Wappler sinusoidal apparatus, one of the types employed by the author, the direct 110 volts electric-light current is reduced to a certain maximum limit by a volt controller and a rheostat, which are set stationary for each treatment. There is also a rheostat in the shape of a drum-shaped spiral of wire and an electric motor moves a contact back and forth along the drum. When the contact is at one extremity of the drum the fixed maximum current flows in one direction. As the contact moves along the drum the strength of the current gradu- ally diminishes and at the middle point is of xero strength, and be- yond that point the current begins to Mow in the opposite direction and gradually attains the fixed maximum strength. A complete cycle would mean the time elapsing between the maximum flow in one direction and the next maximum flow in the same direction. For many purposes the author sets the maximum current at l-l or 20 or, possibly, 2."> milli- amperes. and each complete cycle occupied about live seconds. The current is applied through wet electrodes, usually by means of a four- cell bath, for ten or fifteen minutes. This may be called a slow sinus- oidal current . Morse's Surging Electric Apparatus.- The apparatus- comprises a 1 ZiMitralblatt f. riiirur<;ii\ April I'll. I'.U:!. * AIIKT. Jour. Klortrot lu-rapy and Radiology. \ <>1. \\xvi. No. 1, January, I'.Us. p. tti. (10 MKDICAL KLK( TKK1TY AM) UO.NTCKX HAYS -inusi il.lal generator with 2000 alternations or 1000 impulses a minute and means of applying this current in, say, 20 or 2 1 waves a minute; also 27 sixes of pads for use as electrodes. The currents are induction currents ( f small volume and short duration like faradic currents, hut of greater uniformity, A. B. Ilii'sh had the Morse apparatus applied to lumselt and found contractions detween the electrodes uniform, rhythmic, gentle; no heat or local action; no other unpleasant sensation. Treatment of Flat-foot by Surging Currents. Stimulate the tihialis anticus by a moist elect rode on the inner side of the knee and another at the Untom and inside of the affected area and apply a suridn<>! i/s/ ni 1/1 t/i I'lifn/'. also in use in t he an t hoc' s office, em- ploy- power derived from t he elect ric-li^ht current. F.ither alternating or direct current is employed to run a small dvr.amo "XMicnU insj an alter- natmtr current of the sinusoidal type with a periodicity ot from 12 to 1 xi id cycle- a minute. The polysine u'enerator also delivers different older type- of current, includiiiii the direct pdvanic current. I he author find- the -low sinusoidal current preferable lor a local effect upon muscles and nerve- in paralysis, spastic conditions, and neiirit i-. I he rapid -inu-oidal current i- an exceedingly valuable thei'apeutic a'_"-nt iii heart di-ea-e. for \\hich it is u-ually applied as a hydro-electric I i he i : | ill I bat h or a I < iiir-ce|| ba t h ma \ be employed accord- L t'i whether or not thi 1 general effect of the full hot-water bath with i>onic acid tras i- desirable. The benefit in heart disease lemon irable hoi onl\- m relief from o])pression, but also in more ' ' .' raphic and elect rocardio^raphic tracings and other improved object . ni'iis. In lain for hydro-electric baths it isabsolulelyessontinlthnl t here -hall be no i|'ir<-ct connection of the pat ient , or 1 he water in which he (i.VLVAXJC, FARADIC, AND SINUSOIDAL KLKCTKOTUKUAPY 441 is placed, with the electric-light current. This would be dangerous in case of grounding through the water-pipes and elsewhere. Smith, of Marbach on the Bodensee, is to be credited with the intro- duction of sinusoidal currents into therapeutics. Strubel's "das \Vechselstrombad" is a mine of information, not only in regard to his own use of the sinusoidal current, but of other recorded observations. It is the authority for many of the following statements: Sinusoidal currents applied to muscles and motor nerves produce tetanic contraction, but each curve being a more gradual one requires a much greater strength of current than with faradisrn. The patient experiences a sense of billowy waves in the whole mus- cular system, and these waves of contraction can be noticed if the hand is laid upon the patient. There is a regulating effect upon the blood-pressure, reducing it in cases of hypertension and raising it in low arterial tension. Many different observers have corroborated Hornung's statement that a re- laxed dilated heart may be found smaller after a sinusoidal bath. This is accompanied by increased cardiac efficiency and a higher blood-pressure of a beneficial character. They do not, like hydrotherapy, dilate the superficial blood-vessels either immediately or later. There is no angiospasm or marked blanching of the surface, such as occurs in a cold carbonic acid bath. Lippert classifies the principal effects of sinusoidal currents as: 1. Generally raising the blood-pressure and slowing the pulse. 2. Decided increase in metabolism. 3. Exercise of the heart muscle and of the general muscular system. 4. Assisting the patient to sleep. In a full bath it is estimated by Eulenburg that one-fourth to one- third of the current passes through the body. It all passes through the patient in a four-cell bath. Arteriosclerosis is usually a centra-indication to the use of sinusoidal currents. An extremely feeble heart is a centra-indication and so is coronary endarteritis. Sinusoidal currents are especially indicated in uncomplicated insuffi- ciency of the heart muscle, also even in the most severe cases follow- ing infectious, toxic conditions and overwork, heart disease, with com- mencing failure of compensation, chronic myocarditis, cardiac and vascular neuroses. According to Hornung, the faradic current is to be preferred in treating excitable patients with malnutrition, weakness, and anemia. Hypertrophy of the left ventricle is generally not reduced, but irregu- lar and rapid pulse and cardiac murmurs are greatly improved as well as all the subjective symptoms. The four-cell bath, with a sinusoidal current of 20 to 30 ma. in the hands of Lossen, has given good results in neurasthenia, improving the feeling of apprehension, palpitation, appetite, digestion, sleep, and motor power. Excellent results were had in arthritis deformans. arthritis urica, chorea, muscular rheumatism, cerebral and peripheral paralyses, neuralgias, cramps, anesthesia, and paresthesias. The present author corroborates this from his own experience. Lossen secured improvement in locomotor ataxia, especially in the lightning pains, the disturbances 142 MKDICAL KI.KtTUK ITY A.\I> RONTGEN* HAYS of >en>ation, and to .-ome extent in the ataxic gait. Lossen corroborates Yon Noorden's observation of cases of diabetes in which the muscular pains and weakne--. eczema, and insomnia were benefited. The current fora full bath should always be gradually increased from /ero to about 30 ma. and as gradually reduced at the end of the treatment. The electrode- had better all be the same size, .10 by 2.1 cm. (20 by 10 indie- . and if a triple pha.-e current is used the electrodes are near the nape of the neck, the feet, and the pelvis. Baedeker recommends that the temperature of the water shall be U() F.. and that first treatment of -ix or eiu'ht minute-, during which time a cool wet towel shall be laid on the patient'- head, and that the current shall be followed by general ma aue or vibration. Baedeker has often noticed a temporary heart murmur after the treatment which was not audible before. The symp- tom- of valvular -tenosis. asthmatic attacks and edema, and general mu-cular weakne are improved. Slight forms of aneurysm are bene- fited, severe forms are a coin ra-indication. High degrees of disturbance of compensation are a centra-indication. Strubel's technic is to place the patient in a warm water bath of ( .i.l or H7 F. without an electric current, and in two to five minutes there i- u-ually a reduction of 20 or 30 mm. in blood-pressure from peripheral vasodilatation. Then a current of 10 or 20 or. at the most, 30 ma. is cautiou>ly turned on. Now the arterial tension is seen to rise, the pre ure in the auricles falls. This lessens the dyspnea of certain slight cardiac cases. Increasing the current to 2.1 or 30 ma. raises the blood- piv ure to it- original point. Oradually turning off the current causes a reduction in the blood-pressure, and in most cases it remains below the ordinary level for one-half to one hour. Strubel's work with hundreds of cardiac cases -howed improvement in the electrocardiograph as well as in the ordinary objective and subjective symptoms. He considers the indication.- for sinusoidal current baths to be: (1) Neurasthenia, hysteria, hypochondria -is, and exhaust ive conditions; ( 2 ) myocarditis: (3) valvular le-ion- ; 1 exophthalmic goiter and other thyroid intoxications. It doe- not reduce i he -ize of t he t hyroid gland, t he possibility of toxemia, or of emaciation, but it doe- improve the pulse-rate, the insomnia, and ct rocardiogram : -1 .-elected cases of arteriosclerosis, characterized by the subjective symptoms of angina pedori-. cardiac asthma, mild or severe dy-pnea . and 1 he objective sympt oms of increasing cardiac insuffi- ciency, arrhythmia, marked change- in the form of the heart, and in the electrocardiogram. In such cases strophanthus, Marienbad water to drink, ma a0 to ].)() ma. is generally arts of plain water. According ent . of t he current will 1 raverse < >f bat h- and elect rode- and dif- per cent . for a bipolar bath to ntilv one GALVANIC, FARADIC, AND SINTSOIDAL KLK< TIK )TI FKUAI'V 443 electrode, and the entire current (Biters the body. The nervous struc- tures form the principal conducting paths for the current after it has oassed through the skin. Effects rcyantlcx* of polariti/ are a sensation of warmth and a red- ness of the skin, especially near the electrode, but also more or less general. Effects with the negative dorxtil electrode and the positive electrode near the feet. There is an increase in general sensory and motor and reflex excitability, and often annoying tingling of the skin of the Legs. C'erebral activity is stimulated, and in neurotic persons there may be irritability of temper and insomnia after a few treatments. Neuras- thenic, hysteric, or insane patients are often unable to take this treat- ment, even with the weakest currents, and sometimes not even with the current polarity reversed. Patients suffering from conditions of depression experience a sense of almost immediate relief, and if there has been uncertainty of equilibration, this is recovered from after a few treatments. The pulse-rate is increased, especially if there has been bradycardia. There are increased amplitude of the pulse and increased arterial tension, especially in cases with hypotension. There are in- creased cerebral and sexual activity. Asthenopia and other functional disturbances of the cranial nerves are benefited. Patients with weakness of the cardiac muscle from fatty degenera- tion or produced by valvular disease show immediate benefit after such a hydrogalvanic bath. Multiple neuritis is certainly benefited, and so are anterior polio- myelitis and post-diphtheric paralysis. Tin 1 arthritic diathesis is bene- fited, and medicinal substances are now often added to the water in these cases. Effects with the Positive Pole at the Nucha and the Negative at the Feet. The differen-e between this and the other polarity is in the direction of producing a sedative effect upon the nervous system, but this is not at all constant, and the excitability of the brain and medulla are not generally diminished. The hydrogalvanic bath is used for obesity, but its benefit is not yet fully established. The treatment acts in this disease and in the arthritic diathesis by the production of nascent oxygen, and an increase in oxida- tion and all other tissue exchanges. Galvanic Hydro-electric Baths in Sciatica. This method of applying galvanic currents results in the cure 1 of a large majority ot the cases. Hydro-electric Baths in the Lightning Pains of Locomotor Ataxia. Balsumoff 1 secured relief in these cases by general galvanic baths, followed each time by an application with the current localized in the painful region. Cell-baths and Their Effect with Galvanic Currents. --These are a specific for locali/ed neuritis: the same strength or a greater strength of current may be used as it' the electrode were not formed ot a mass of liquid. The author's plan of having the patient wear a stocking or a gauxe bandage prevents an irritation at ihe upper surface of the liquid an effect of oxidation. Adding glycerin to the water has the same effect. The addition of a medicinal substance enables one to secure a cata- 1 First Intermit. Coim. <>t' 1'hysini hrrapy. Licjre, 190.">. MKDICAL KI.F.l TKK Tl'V AM) K )\T(i KN" KAYS phnretic effect. Schnee's four-cell l>ath i Fiji's. 2 Mini 297") or general ualvanic l>ath> >iirc; > f(l in the pains of locomotor ataxia, swcllinjj; of the U'U>. -riatic nruraluia. chi'onic muscular or articular rliruniat ism. In inveterate chronic articular rheumatism each galvanic hath may follou'ed liy I'aradi/ation of the spine. 1 he modification >ho\vn in Fiu\ 20S forms an excellent means of Ill' 1 i-iiiTi'H I - wilh -;i fel v ;i IK 1 -i' ( -:i' many difterent nerve and joint ai'fect ions ; (JALVANIC, FAKADIC, AND SINUSOIDAL KLKOTROTHKKAPY 445 xoidaj four-cell haffi has a local effect which may he very in I he treatment of Haynaud's disease. Here the four-cell hath is excellent, acting by local vasodilatation. The current is an al- ternating one. and consequently hoth poles produce tin; same effect. (Vll-haths. whether galvanic oi 1 otherwise, have less effect upon cardiac rhythm and arterial tension than a ,u'eneial hath with the same kind of current . ( '< ll-hothx inth (ialranic Currents in Ncnritixand Muscular Alroph'/ of Traumatic Origin. The arm or the leu 1 is in a negative hath, while the positive 1 electrode is applied between the shoulders. A current of 12 or 1.) ma. may he applied tor fifteen or twenty minutes ('very dav. Hydro-electric Baths with Sinusoidal Currents. Sinusoidal currents with a tension of about .'>() volts, wliich have recently come into such prominence, are y the electrocardiograph in arterio- sclerosis and organic and t'unct ional cardiovascular diseases set' page 320. Kaab advises the use of a higher rate of alternation 14,000 instead of ~>000 per minute in order to avoid pruritus from sinusoidal hydro- eli ctric bath-. He also think- it a mistake to treat cardiac cases from the -tart with sinusoidal currents exclusively. 'Their tension is o() volts, and in -ome cases the faradic current with a tension of only 8 volts is preferable. Lippeir has made 140 observations regarding these effects, and found that I here is an increase in blood-pressure. It may be 10 or lo .-.. more after the bath than before. This may be accompanied by a reduced pulse-rate. There is a pronounced increase in tissue exchanges. Weakened and atrophic. cardiac, and other muscles are strengthened. Arteriosclerotic and neurasthenic patients who have suffered from in- >\ .ma are eiiableil to sleep. These (Mil-rent- have a general tonic effect upon the tissues. They are excellent in dermatoses dependent upon deficient tissue exchanges, such as inveterate pruriginous eczema and urticaria. They are excellent in cases of paralysis of peripheral nerves, of con- ble muscular atrophy, and of progressive muscular atrophy and : r ci mdit ii ins. They are very soothing in cases of neuralgia and of muscular or ; : ' icular pain. Their effect in n nal colic is excellent, and decided diuresis is pro- :ed. The effect of hydro-electric baths with sinusoidal currents in cardio- va-cular disease is decidedly different from that of triphase currents d in the same \vav. Albert \Yeill and M. Mougeot* have; made ai'eful observations in a number of cases, The temperature of the nth was M T J to :-!."r ('.. and the patient remained in it for ten minutes fore the currents were applied. Measurements were made of thear- 1 and capillary pressure before and after the simple immersion, fter every five minutes of application of the sinusoidal currents. 1 . cardiac area was registered by the oil hodiograph before and after tii' 1 treatment. 'I he radial pulse and the capillary pulse were recorded mi a revolving cylinder at first in the simple bath, and again after :.' ;. M imiies o! sinusoi(lal currents. The electrodes were immersed 'he outer surface of the thiidi. the left side of the back, and the . . ' -idf o] t he f n nit of t he body. 111-;!' re.-ults showed a marked increase in arterial tension, just mi the effect of baths with triple-phase currents: little 1 '. capillary pressure; a change in the arterial pulse in- ral resistance was not reduced, but was even in- \vas dicrotic. thi- characteristic was diminished. ri ' - increased in size. A dilated hvposvstolic i in -i/.e. but tin- change is much less certain than fit-, which reduce peripheral re-ist aiice. fo thera|)eutic irnlicai ions i- that lu'dro-elect ric GALVANIC, FAKADIC, AND SINUSOIDAL ELK( THOTHKRAPV 447 baths \vitli sinusoidal currents arc useful in functional hypotension, or when it is present without cardiac lesions; also in mitral disease, when the cardiac muscle is still intact. If there is such a tiling as pro- ducing a tonic effect upon the heart by a peripheral vasoconstrict ion, this is what the bath with a sinusoidal current does. This action would be contraindicated in uncompensatcd dilatation of the heart and in a variety of cardiovascular conditions, where the indication is to reduce the blood-pressure and the labor imposed upon the heart. Margaret (/leaves has found that hydro-electric baths with sinu- soidal currents give remarkable results in neuro-arthritic and cardio- vascular diseases. Kellogg has also demonstrated the same excellent results from baths with sinusoidal currents. ('cll-bnth.^ irith Xi'nttxdidal Currrnt*. -These have an important application in gynecology, as sitz-baths. Hydro-electric sitz-baths with a sinusoidal current of 2400 to oOOO periods a minute have an excellent effect upon menorrhagia due to fibroma, and also upon eoccygodynia and hemorrhoids. Paull 1 has obtained subjective improvement without much objective change in suppuration of the adnexa and rctroflcxion of the uterus. The sitz- baths contain three 1 electrodes one in front, one behind, and one at the side, so that the current may be directed through the pelvis in different ways. Sinusoidal cell baths are useful in all conditions for which a general sinusoidal bath is used if the condition is confined to one limb. Neu- ralgia, rheumatism, and gout are examples. Hydro-electric Baths with Triple-phase Currents. The source of current is a rotary transformer, actuated either by the direct or the alternating electric-light current, or by a battery of accumulators (storage-battery). In the latter case the battery should generate 12 volts. Three different wires leave the transformer at points equally distant, and each is traversed by an alternating current having the character called sinusoidal. These currents are not synchronous in the three different wires, but have a difference in time equal to one- third of a period. The regulation of the currents is best accomplished Fi9(). Sinusoidal current. Fit:. .100.' I nple-phase current. if the currents from the rotary transformer pass through the primary wires of three transformers, in which the secondary coils are at an ad- justable distance from the primary, and consequently the induced triple-phase currents supplied to the three electrodes in the bath may be varied in strength. About twenty periods a second is desirable for these currents, and 100 to 140 ma. is the usual strength of current in a general bath. The same periodicity, but a much weaker current, is suitable for use in a cHl-bath or for ordinary electrodes with which the full strength of the cm-rent passes through the patient. In some general baths with medicated solutions, on the other hand, a much stronger current, such 1 Zcitschrift g. diuet. u. physik. Therapie, vol. viii, November 1, 1905. as HOI) ma., i- required, because a smaller fraction passes through the patient 's body. The physiologic effects are to excite a tingling of the skin, which is extremely di-agreeable if the periodicity ot the current is too rapid. The triphase current -upplieei by some industrial and electric-light cir- cuit- has a periodicity of about 12100 a minute, which is about twice as rapid as i- desirable for therapeutic purposes. A rotary transformer i- u-ed to change this to a triphase current with a periodicity of about 1_M)0 a minute. The more rapid periodicities also produce muscular contraction -imilar to what would occur from a general application of a strong faradic current, and this also disqualifies them for therapeutic use. I'ri phase currents of t he proper st rengt h and periodicity for general h ;h- produce capillarv dilatation, increased metabolism in muscular and oi her t issues, and a red net ion in blot id- pressure. They are curative in peripheral paralysis, muscular atrophies, and progressive myo- paihies. Applied in moderate strength in cases of neuralgia and pains 1 the muscles and joints, they are soothing. They have a specific icia! effect upon the heart, relieving dyspnea, irregular rhythm and p; Ipil ition, and hiuh arterial tension. They are especially bene- e high arterial tension of uricemia. the menopause, com- iiii arteriosclerosis, aortic atheroma. simple or syphilitic. 1 hev fail otilv in pronounced cases ot renal sclerosis. \ iei'1 \\eill and Mougeot 1 find chang'es in the form of the radial pulse tracing consisting in an increased amplitude of the systolic wave, an increase or a reappearance of the wave of arterial elasticity, an in- crease- in dicrot ism. I he\' find no increase' in the amplitude ot the lary pulse. They find a distinct reduction in the size of the heart if it has been dilated. ('ill /;/;'//.- ///'/// T/'ijt/i -/il/nsi Curr< ///*. These are especially useful ;n llayiiaud'- disease and other local conditions of the circulatory dis- t urbaiice, \\ it h capillary or arteriole constriction. They are valuable in .!;d in juint legions. They have an important application as four-cell baths m i he treatment of rheumatism and lithiasis. OZONE \\heiii ,'ei an elect ric spark, whether powerful or almost impercept- - ihrmiLih the air, ozone i- produced bv the action of ultra- Upoli i he oxygen of the air. This very active form of d eftects upon living organisms, and it seems certain le p; rl of ihe benefit derived f roil i the application of or i! :LJ h-i ri < |in 'tic\ currents is due to the absorption of ' t he luni!> or through the skin. I' effects in a concentrated form are poisonous. Bacteria are 1 liH- -uccumb in ten minutes if kept in an atmo-- - milligrams of < 1/1 me per liter. A t herapeiit ic o-i I to :; milligrams per liter of air. and a single' ten minutes \\ill increase the 1 proportion of oxv- -ubiiormal, and al>o I he number of re-d blood- ] " < I'n-ial effect from a course of treatments is an '. capacity and a reduction in \\hite blood-cells if ':,. 1' i- indicated GALVANIC, FAKADIC, AND SINUSOIDAL ELECTROTHERAPY 449 and whooping-cough. It is used also as a general tonic in many de tated states. It is to be recommended in the strongest terms for use in a work- room or office where a large number of persons are employed, and where it is possible to secure good ventilation, but no sunlight. A desirable outfit may be obtained from the General Electric Company, and if kept in operation during business hours makes a wonderful difference in the health of the employe's. Method of Use. The production of ozone by sparks of perceptible size is accompanied by the production of much nitric acid and other substances which unsuit the air for inhalation. It should, therefore, be obtained from the silent discharge which takes place from metallic points charged with very high-tension electricity and which forms an effluve. An ordinary whisk-broom connected with the terminal of an Oudin resonator and held near the patient's face is a simple and effective means of giving inhalations of ozone. Stronger inhalations are ob- tained by surrounding the Oudin resonator or the Guilleminot spiral by a glass jar through which air can be inhaled by the patient. The ozone generator, shown in Fig. 301, has a leading-in wire to be connected with an Oudin resonator yielding a high-potential high-fre- Fig. 301. Ozone generator from high-frequency current. quency current. The vacuum chamber thus charged is surrounded by an outer glass held in the patient's hand and separated from the charged glass by a space in which innumerable sparklets pass through the air with violet and ultraviolet rays. This changes a considerable portion of the enclosed air into ozone. The ozonized air is forced through this space and then bubbles through pineneedle oil, or some similar liquid, to absorb the nitrogen pentoxid before it is inhaled by the patient. The arrangement used by Albert Weill for ozone inhalations from a static machine is shown in Fig. 302. The discharging rods of the static machine are within a dis- tance of an inch or two, so that a stream of powerful sparks passes between them. The outer coat- ing of a Leyden jar whose inner armature is connected with the positive 1 pole is grounded. From the outer coat of the negative Leyden jar a wire leads to an in- sulated metal rod which enters the ozonizing bulb, but does not touch its glass walls. A large part of the outside of the ozon- izing bulb is coated with metal, and from this a wire passes to the earth. Air is driven through the ozonizing bulb and inhaled by the patient. A brush-discharge occurs between the metal rod and the glass Fig. 302. Dias -l.">0 MEDICAL ELECTRICITY AND KONTCEN KAYS wall of the ozonizing bulb, whicli fills the bulb with violet and ultra- violet liirht, the latter causing a profuse generation of ozone. Chany 1 has made valuable observations upon the influence of voltage on t he format ion of oxone. To be perceptible at all. several thousand volts an 4 required. The .")0-cycle alternating elect ric-liii'ht current and a larire Kuhmkorff coil is a most effective generator. The voltage at which oxone is per- cept ible is cliaracterixed by eflluve. At 40 per cent, of this voltage the discharge is like a ram o| lire. The power of oxone production is as the square of the difference in potential between the armatures of the ( i/.olll/.lllU' t lllie. O.SliO l.oSO li is useless to KCC). The chronaxie method is suited to the physiologic laboratory, not to the bedside, and may take hours to examine 1 one patient. The condenser discharge method takes longer than the faradic and does not give such precise information, and has the great disadvantage of stimulating antagonistic muscles. Larat- tests the muscular response by its lateral expansion. A circular band or bracelet, inexpansible except 3 cm. of elastic with a rubber bulb connected with a Marey's drum, surrounds the limb. The recording cylinder makes a revolution in twenty minutes. The 1 muscle is stimulated by the bipolar method. Abruptness of rise and fall in- dicate intact nerve supply, and gradual rise 1 and fall the reverse. Nerve Testing at Time of Operation. The field is dry; a glass rod being placed under the nerve. A metal probe electrode applies a weak intermittant faradic current. Return of faradic excitability al- ways precedes return of voluntary power. ;i The Daisy foot switch is useful for nerve and muscle testing (Massey). Electric Treatment of Nerve Injuries. The galvanic current is used until a response occurs, and later the faradic current until full faradic response is obtained. Splints and massage are often useful.'* The static induct o-resonat or is used for treating paralyzed and atrophied muscles (page 76). 1 Amcr. .lour. Electrotherapy :iml Radiology, vol. xxxvi, \o. .">. June. I'.US. p. 161. -Traitr I'nitique d'Klectricitc' Mrdicalc. I'.HO. ; l!o\v1cY-Bristo\v. Brit. Mrd. Jour.. January 5, 1'Mv 1 \au:. -Joseph Riviere. Arner. Jour. Electrotherapy and Radiology, vol. xxxvi, No. 1, January, 19ls. p. >. " H. !'. Pilrher, Amor. Jour. Electrotherapy and Radiology, vol. xxxvi, No. 9, September, 191s, p. 238. PHYSIOLOGIC AND THERAPEUTIC EFFECTS OF ELEC- TROMAGNETS So many excellent and entirely unbiased observers have tested the matter with magnets of every possible strength and without any discoverable effect, that the author feels that these instruments cannot at the present time be considered as being of practical value in thera- peutics. He does not at all wish to be understood as thinking that prolonged exposure to a field in which such tremendous energy is operative is without some effect, and perhaps usually a deleterious effect, upon the human system. But it does not appear to have Fi.tr. .'-SO.'?.- -Therapeutic application of plectromagnetism. an effect which can be put to practical use. The subjective symp- toms of a sensation of light and a feeling of pleasure or repulsion according to the polarity are liable to be partly of suggestive origin. Tt certainly produces no muscular or motor nerve effect. The bene- ficial effects which have sometimes occurred in tic douloureux, congen- ital myotonia. and different neuroses, are apt to be transitory and are possibly due to suggestion. Cases of facial neuralgia, intercostal neu- ralgia, alcoholic neuralgia, and nervous insomnia have sometimes shown very great improvement. 453 454 MKDICAL KLK< TKICITY AND KOXTGKX HAYS Technic. -The best technic appears to consist in the use of a current which is reversed about 100 times a second, and which is of low voltage but high amperage. Outside df the role that they phiy in all kinds of coils, motors, and other apparat us. elect romagnets have two distinct uses in medicine. One is the extraction of steel and iron particles, especially when embedded in t he eye, and anot her is t heir application for a supposed effect upon the brain and other parts of the nervous system. Klert mma^net for removing bits of steel from the eye. Electromagnets for Extracting Foreign Bodies from the Eye. 'I!, 1 electron a'jnel !'i'_ r . .'!OI) has a large, soit-iron core, terminating : ul tn :, rh sometimes different iron tips are attached. There i- a '! ' ' ' ' danger in employing tremendously large and powerful electromagnet- ch are capable of drau'gini;' a bit of steel or iron through the t:iei|i;i o! the eye and producing irreparable lacerations. ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM THK general problems of electroneurophysiology have been treated elsewhere in this work, and the general relations of electricity to ner- vous irritability have been touched upon. In limiting, therefore, the consideration of the use of various forms of electric action to diagnosis and to treatment of diseases of the nervous system, it is with the tacit understanding that the present chapter concerns itself with the most practical of issues. The applications of electricity in the diagnosis and treatment of discuses of the nervous system are increasing in number and in value every year; the introduction of newer currents is constantly widening the field, and with each new installment of scientific journals, new processes arc described which often find a permanent place in nervous therapeutics. The following pages have been prepared to present the present-day aspect of what has been demonstrated to be of per- manent value, as well as to endeavor to point out the merits of some of the more important of the later advances in the science of electro- therapeutics as applied to the disorders of the nervous system. The topics to be discussed will be as follows: (I) The use of electricity in diagnosis. (a) Diagnosis of disorders of peripheral nervous systems .motor and sensory. (!>') Diagnosis of disorders of central nervous systems. (II) The use of electricity in therapeutics. (a) Therapeutic applications of electricity in diseases of the peripheral nervous system. (/>) Therapeutic applications of electricity in diseases of the neuro- muscular apparatus -neuromuscular disorders. Therapeutic applications of electricity in treatment of organic disease of the central nervous system. Therapeutic applications of electricity in treatment of func- tional diseases of the central nervous system. (III) Klcctric sleep and death due to elect lie currents. DIAGNOSIS OF DISORDERS OF THE PERIPHERAL NERVOUS SYSTEM Motor Reactions. The principles of nerve stimulation and mu>de reaction have been considered elsewhere at great length. There remain^ here to take up the specific applications of such teachings, particular- izing on the subject of the reactions of the neuromuscular apparatus for diagnostic purposes. It is to be recalled that when a galvanic current of sufficient strength is passed through a neuromuscular arc, it causes a contraction in the muscular portion of the arc, or in the particular muscle if the arc in- cludes but one muscle. This contraction, as has already been seen, is not for the galvanic current a continuous reaction. It takes place only when toy MKDICAI. KI.KeTKlelTY AM) KnNTOKN HAYS ( M Tie current stops. /'. i ., at current opening. 'here i- a sudden increase in force of current. /here is a marked decrease in strength of current. 'he direction of the current is reversed, anode to cathode; ide to am " le. Kxperimentat ion on lower animals has permitted the laying down of certain la\vs re-'ulat im: the actions of the galvanic current i. e., I'thiiivr's laws, which have been discussed elsewhere in this volume. The-e laws have a limited application in human neuro-electric technics. The laws of human normal muscle contraction then are for an intact nervous or-ani/.ation to be expressed as follows for weak, medium, and strong current s. I. ('('1C. for weak currents fcathodal closure contraction only). II. ('('1C, AC1C. A< >C. in order of activity for medium currents. III. CCH'et, AC1C. AOC. CC1C, for strong currents (cathodal closure tetanus, aliodal closure contraction, etc.). '["he strength of such currents has been accurately measured by Simi/iiii: and Krb and a number of students. Stintzing has examined most of the muscles of the body, to determine the minimum amount of current that will cause a cathodal closure contraction, and has con- structed table- which give the average values in the different muscles and nerves of the body. These tables are of great value for compara- tive purposes his faradic tables are of little practical value for the average practitioner: his galvanic tables, however, are useful, and are here printed. It must be remembered that great variation exist- in different nerve-trunks to the same strength of galvanic current. Such variation exists for differing ages, and have been made the subject of special researches of a very intricate and extensive nature by numerous experimenters Mann. 1 Westphal. Thienisch. and others. XKCROMCSCCLAR INTZING'S TAHLE FOR GALVANIC S( 'ALE OF NEf i:.\' ITAI'-ILITV IX MILL [AMPERES. I. < JUKI; LIMIT UPPKH LIMIT VAI.I-E. VALVE. Ma. Ma. 1 M'.l-r"ilni" ;i;i!i. '.!!- O.O.") 0.2S .0.10 0.44 0.20 O.'.tO !. !' 0.20 2.00 ' ' ' 0. 10 i 'TO 7. I if. (I. Id 2,")0 V M> ' [)..")() 1.40 ' ' 1 ' 1 M ,1 i '/ i \ ^.i 2.r>o 1 1 t \l \ II '.II 2.00 2 HI) i HI 2.70 ! in 2 .")( 1 Method < >{ Study for Disease of Neuromuscular Apparatus e MI i'- motor nerve or 'he end-plates become tune! i(,n<, certain ('lectric changes are apt to take 'h their (jiiant itat i\-e and (jualit at i\'e reaction ' . -pecial i \" j >^~- oi curi'ent s. : i-lcftrii itc in<'ilic:tlf \'.<^'-'>, f ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 4o7 The qualitative changes, which are the more readily observed, con- sist in a change in the formula of contraction, or a modification in some particular of the normal formula. Such variations may depend upon purely accidental modifications of contact, of saturation of electrodes, etc., but assuming the teehnic to be five from graver errors, these changes are dependent in large part on the more or less superficial seat of the nerve-fibers. Diffusion produces a certain amount of scattering for the deeper seated nerve- fibers, and thus only a part of the current registered by the galvan- ometer is utilized. Fat makes considerable variation, and, as has been noted, the age of the patient is of moment. This latter fact is of importance in determining the Krb reaction in children thought to be suffering from tetany, since very frequently much heavier currents are needed in infants and children. Further modifications depend largely upon the rate of make and break in an interrupted (faradic) current. Tetanus usually results if the interruptions are over twenty a second. The introduction of the induction-coil, however, has caused a number of complications in the tests usually applied, since the discharges are usually irregular as to quantity and as to duration, and d'Arsonval has shown the great importance that is to be attached to the form of the wave of the electric impulse. This has led to the introduction of mechanic forms of making and breaking by Leduc, since a greater amount of regularity in making and breaking results than when the induction-coil is employed. They are further capable of more accurate mensuration. Leduc has shown that when the impulses have only a duration of about y^ 1 ,,^ second, and follow each other at the rate of 100 to the second, the best type of effect is produced. Thus Leduc's table is of interest in this connection: 1 DCKATION OF E. M. F. UKqriKKI) TO PuODTCE IMITLSE. Mrsrn.AK CONTRACTION. SKCONDS. VOLTS. 0.00001 22.0 0.00010 15.0 0.00020 13.5 0.00030 12.0 0.00040 1 1 .5 0.00050 10.5 0.00060 9.5 0.00070 . 9.0 0.00090 S.5 0.00100 7.0 0.00200 7.5 0.00300 S.O 0.00100 S.5 0.00500 9.0 0.00(100 9.5 0.00700 10.0 0.00X00 11.0 0.00900 12.0 The important advance that lias come about by the introduction of Leduc V apparatus is that the amount of degeneration in the neuro- muscular apparatus is subject to more accurate mensuration (see p. 494). Heretofore we have had to depend on the crude 1 expression that R. I), is present. By means of the Leduc apparatus an estima- 1 Arch. iI'Elec. Mrd.. September 15, 1903. 458 MEDICAL ELECTRICITY AND RONTGEN KAYS tion of the extent of disease in the neuromuscuiar mechanism may be secured. In testing the muscular apparatus, a knowledge of the motor points is desirable if the reaction of the adjacent or subjacent muscles is to be determined. Such points represent the sites at which maximum etYect.- may be obtained with minimum currents. These arc usually the points of direct ingress of the motor nerve into the muscle mass. In the ca>e of superficial muscles, particularly in lean individuals, they are sharply delimited: but in fat subjects, and for deeper muscles, dif- fusion tends to confuse the picture, often very material!}'. They are illustrated in IMates 1 >s. 1 ' t 1,-. L';il\ :mir or far.-iilic or rli\ t lunic currents. A smitllrr :ict ivc clcr- Modes of Testing. Tin 1 horizontal position is uenerallv advisable !' relaxation as pos.-ible. In some p.-itients the sitting p"- i'i|Uall\ convenient. The indifferent electrode, preferably ; ' "< iii'jhlv moistened and placetl upon t he spine, eit her - Up|" ' 01 lower part. > le] ie;it lni^ larjielv Upon the region to be - e; d 1 1 ulc >hou!d be applied firmK' to the skin, and held .' : '' ' ' '. < I'jht rif the lind\-. the hand, or a banda.ire. The e\ ; 'In; :!,: <''< '. knov, . . oriL r mal \\ i\\\ him. ELECTRICITY IN D1SKASKS OK THE NEUVOl'S SYSTEM 459 The indifferent electrode; is preferably made; of block tin - 3 ' 3 inch thick, and '2 by 3 inches in area. For this I have slip-covers made of absorbent felt. The part of the body on which the indifferent electrode is to be placed should be thoroughly washed, using tincture of green soap. The slip-cover is thoroughly wet in a solution of bicarbonate of soda, consisting of 1 dram of bicarbonate to 4 ounces of water. The exploring electrode, as shown at 13, Fig. 300, consists of a circular disk made 1 of pure; block tin, and having a groove around it so that it can be easily covered with a piece of chamois. This chamois is to be thoroughly wet in the bicarbonate of soda solution. The area to be explored should be thoroughly cleaned, using the usual green soap tincture. This is to remove any fatty material which would offer a high resistance. In place of the usual interrupting handle, Fi-. 300, C, I use a combi- nation electrode. B is screwed into the handle, K. Inside of this handle is a compression spring. The central metal rod F has the upper SIP Hard rubber Graduated in pound- I Metal Metal Fij;. 'iUO. Author's exploring electrode with standard pressure. part graduated, so as to indicate the amount of pressure with which the electrode B is held in contact with the skin. As a rule, using an electrode '. inch in diameter, a pressure of 1', pounds is sufficient. In circuit with this holder is placed a separate interrupting handle shown by Fig. 300, 1). This is held in the left hand of the operator, so that as the exploring electrode is moved from one place to another, the pressure used to make and break the circuit in I) will not affect the contact pressure between the electrode and the patient. This is a most important point, as the resistance will vary according to the pressure. This is more particularly so when a sponge electrode is used in place of the chamois-covered metal electrode above described. Investigators with lartre experience advise the beginning of an examination by means of the faradic cm-rent. In this manner it is held that polarization is prevented. Furthermore, if no alteration in fa- radic excitability is obtained by minimum currents, it usually toll<>w> that there are few changes to the galvanic current. In beginning the -ItiO MK.ru AI. i:i.K.c'r::n rrv AND KONTCKX HAY'S te>tin<: it is advisable that the exploring electrode be connected with the negative pole of the secondary current. The strength of the current i> uradualiv increased until the beginning of excitation is reached, and the number of millimeters that the secondary covers the primary is noted. A comparison of the two sides of the body is always advisable in carrying out tots with the faradic current, since accurate methods ol measurement are not usually available apart from a physiologic laboratory. St hit xiim~ has given t a hies for the faradic current as follows, the figures referring to his own coil: FARADIC i:\ClTAniJ.lTV OF XKRVKS. *Xt!ntzing.} Borxn ARIES. f" pin r. Loiri-r. (Millimeters between the primary and secondary coils.) 1. Spinal fim'ssory . . . H"> 130 2. MiiMMilucinaiicmis . . 14,-) 12.i :;. Mental . .140 125 1. I'lnar I. 140 120 .->. I'lnar II. . 130 107 ii. Frniual . 137 120 7. Zyp.malic 13") 11.") v. NlY.lian . 13") 110 '.'. IVruncal . . 127 103 III. Cr iral .... 120 103 i I. Til.ial 120 <)"> 12. Railial 120 () ;:; Facial. 132 110 In testing with the galvanic current, we follow out the same pro- v. fir.-t obtaining the minimum reaction, and then ascertaining ;: the force of muscular contraction follows out the law of progression, ('('(' A( '( ' ,\(>C ('((' (cathodal closure contraction is greater than aiiodal eh isure cont ract ion. etc. ). The strength of the current necessary to produce a reaction is then read off on the milliamperemeter. Thus a record of a radial nerve may read ;;- !' illou> : (Minimal <:;'lM>d:il closui'e contraction occurs with 2 ma., etc.) \\<' have -ecu that variations in com ract ion in diseased conditions to the fjiiantity, as to the (|iialitv. or both. Thus. nil. or abolition of contraction mav result. For *' in contractility is obtained in st rvchmn-poison- iii tetaiiy, and oilier affections io which attention '' '. Such an increase is determined by comparison 1 . A decrease in nerve excitability is obtained in many *' neiirii [iol io my el it is, etc., \\ hile an abolit ion may be present in ' In ' ',- coiisisl m variations in the form of contrac- i"ii, -ui-ii a.- r>loune--, and variation from the typic iral\'anic formula. ELECTRICITY IN DISEASES OF THE NEKVOUS SYSTEM 401 A complex reaction, both as to slowness and variation from the typic formula, constitutes the well-known rcactio'n of degeneration. Reaction of Degeneration. This may he recognized as existing in several decrees which have been arbitrarily named slight, medium, and severe 1 . Anomalies of Fa m< lie E.rcilahiliti/. These may be discussed before the main subject of the' reaction of degeneration syndrome is con- sidered. They consist, in the main, of hyperexcitability and faradic loss, or the phenomenon of exhaustion. Faradic hyperexcitability is found in conditions in which muscular rigidity is usually accompanied by an increase in tendon excitability, such as is seen in tetany, in tetanus, in many of the occupation neuroses (writer's cramp, telegrapher's cramp, violinist's cramp), in paralytic posthemiplegic states, both of recent and of remote origin, and in those cases in which irregular involvement of the pyramidal tracts (post- hemiplegic chorea, posthemiplegic athetosis, posthemiplegic pseudo- paralysis agitans) takes place. Faradic exhaustion is a constant symptom in many myopathics. in many tabetics, in myasthenias, in Thomsen's disease, and in a number of conditions which show reaction of degeneration. Anomalies of Galvanic Contractibilitif. Galvanic hyperexcitability has been spoken of. In addition to the disorders mentioned, it is a frequent accompaniment of conditions in which mechanic hyper- excitability is also present, in multiple sclerosis, in spastic paraplegic states. Galvanic loss is a constant accompaniment of the terminal stages of neuro muscular degeneration. Galvanic Inversion. Rich's Formula. In some instances the phy- siologic order of (TV A( V>AOO >COO may be partially inverted to read ACOCCOAOOCOC; or when ACC>CCOCOOAOC occurs. a total inversion has taken place. In some instances the formula des- cribed by Rich is present, as follows: (VC >ACC ACKWOC. These inversions are all varieties of the reaction of degeneration, and their presence is an indication of a degeneration occurring in the lower motor neuron, either in the ganglion-cells of the anterior columns of the cord or of the nerve-fibers passing from these cells to the muscle. It is absent in affections of the primary motor neuron system per se. If the re- searches of lotyko are correct, the reaction of degeneration may be in- terpreted as a failure in the striated elements of the muscles to react, with a persistence of sarcoplasmic irritability. Longitudinal Reaction. This special application, first referred to by Remak. occurs in those muscles which show the reaction of degenera- tion. In such muscles the contraction is more readily brought about when the testing electrode is applied at the distal end of the muscle, rather than when the application is made to the motor point, which latter has. as Doumer has termed it. lost its importance. The im- portance of the longitudinal reaction, which is great, is that it is a more delicate test, and that in old. long-standing cases, in which the nerve paralysis is marked, as in chronic neuritis, old poliomyelitis, etc.. contractions may be brought out though they fail when the electrode is applied to the motor point. In certain cases of sluggish reaction the longitudinal reaction test should be employed to settle a doubt as to the presence of reaction of degeneration. Tims, if a stronger and slower contraction takes place with the electrode at the distal end of the muscle 4t')2 MKDICAI. KLKCTH1CITY AND HONTGKN RAYS than when placed over the motor point, reaction of degeneration is posit ively shown. In practical work on electric testing a number of anomalous and contradictory results have been obtained, and it is quite certain that the entire subject of the reaction of degeneration is in need of new restating. At the present time newer results, which have come about bv the Use of Leduc'- new commutator, have not been codified, but thev are certainlv de-tmed to be ot immense practical use. \\ e have al- ready alluded tn the fact that more accurate determinations are pos- sible by this form of apparatus, and data are now rapidly accumulat- / _ as in i he minimal duration of current needed to make visible mus- cular contractions, and as to the critical frequency at which an inter- rupted current cause- a muscle response. l)i rdn/itm nt of HI iictio-n of Degeneration. Thi* syndrome has a more or less regular course of development, both as regards the nerve n action and the muscle reaction in point of time and in course of events. Both of these are conditioned bv the character and the severity of the lesion. Following the complete section of a nerve- .. there i- usually a short period of increased irritability in the nerve to both faradic and galvanic currents. This may persist for a few days three or four - and is then followed by the period of diminution, the decline reaching the normal about the fifth or sixth day. and then lly sinking below, so that about the tenth day the nervous irrita- bility has completely disappeared. The course met with in tin mnxdcx is somewhat modified. Faradic excitability seems to diminish from the very onset, and has disappeared entirely in about a week or ten days, while the reaction to ualvanic currents, which has steadily decreased for about a week, then under- goes a more or less abrupt reversal, and an increase in excitability with -bluish contractions takes place, mechanic irritability of the e appears, mid A('C ('('(' appears in many instances. Rich's inverse formula begins to appear, and this may persist for some time (ven for weeks. Later, diminution, j^oinjz on to abolition, takes Sherriiu:ion. in his Krasmus Wilson lectures.' has trone over this : ' ' n :.:- cases of nerve section, and has found that the muscles ed cease to respond to the faradic current in from four to seven 'i -. atid ':.; '. even v.nh the iralvaiiic current, there mav be loss ot r t lii tenth day. The appearance of slu.u<>ish muscular ' on 1 1 e reversal of pola nt v 1 a kes place about 1 he same t line. I': 'he tial -taLies of degeneration the ti'alvalilc excitability dimin- I :.' A< X ' r-i disappears ent irelv, and is soon followed by t he e ( '( ii i. d the ('<"('. i he A< '( ' persisting the longest. The may -till be pronounced, even aftei 1 the complete ' 'he \( '( '. Ihe lonnit uduial react ion finally disappears. ., showji b\ ( iiiilleminoi (p. :!]s. Knulish trans- pecial i yi ie of elect ric and mechanic Ki'i i as cha I'act enst ic of pat lent s . or m\ ' it ' iina con^enita. In t h<'se die and L;al va me elect licit}" m'c excit al lility as \\ell, but t here is a Miircli, inuii. ELECTRICITY IX DISEASES OF THE NERVOUS SYSTEM 463 distinct increase of the muscular excitability to these forms of stimula- tion. Testing with the galvanic current shows that the muscles react only with the closure contractions, the A(X 1 = CCC. The tonic, slow, and prolonged nature of the contractions is pathognomonic. When stimulated by the faradic current the muscles respond normally to minimal contractions, but on increasing the strength of the current the reaction becomes markedly prolonged, persisting for a number of seconds after complete removal of the current. This period of dura- tion tetanus, as it has been termed, to both interrupted and continuous currents, is very characteristic. M ijdxthcnic Reaction. Another type of muscular reaction is observed in the same kind of patients, and in a number of conditions closely allied to the neuromuscular affection known as myasthenia gravis. This reaction consists in the great fatigability of muscle when exposed to the tetanizing action of a persisting faradic current. It differs from the normal physiologic curve by the very rapid onset of the fatigue drop. At the same time the muscular reaction does not depart from the ordinary type on exposure to the single shock of the direct current, notwithstanding the presence of tetanic fatigue. Neurotonic Reaction. The exact significance of this reaction is unknown. It consists in the tonic persistence; of contraction after cessation of the current, whether it be faradic or galvanic. Further, there is an exaggeration of the anodal response, made evident by t he- early appearance of AOC and A(V tetanus. Reactions in Lesion* of Spinal Xcrrc Center*.- Xot only does the investigation of the muscle at the site of its motor points offer con- siderable information concerning the condition of the nerve-supply of the respective muscles, but it not infrequently happens that an entire group of muscles is affected by the loss or reduction of function, and a careful study of a reaction of these- groups will lead to a differential diagnosis between the affection of the peripheral distribution as con- trasted with a lesion of the motor centers in the 1 spinal cord. Thus it is well known that electric testing of groups of the muscles of the hand will enable one to differentiate between a lesion of the trunk of the median nerve and a lesion of the first dorsal segment in the spinal cord. As lias been well pointed out by many authors, in the latter case the whole of the thenar and hypothenar eminences will be in- volved. ;is well as all the interossei and lumbricales, whereas if the lesion is confined to the trunk of the median nerve, then the hypothenar. the interossei, the two inner lumbricales, the abductor pollicis, and tin- inner half of the short flexor will escape, since all these receive fibers from the ulnar nerve. It. therefore, becomes a matter of considerable importance in the differential diagnosis of peripheral lesions due TO neuritic process, from central lesions due to myelitic process, to bear in mind the segment al distribution of the motor centers in the spinal cord, \\hile most of these facts are commonplaces for the neurolo- gist, and have been very carefully investigated by followers of this branch of medicine, it is essential, in the electric study of the diseased 4f)4 MHDK AI. KI.KCTKKTI'Y AM) H<").\T< , EX HAYS Il.TI! CKK- IV. CKKVICAI.. V. < KKVHAI.. VI. ( 'KKVICAI.. VII. CKKVI- VII I. CKK- DORSAL. \ 11 \i.. CAI-. VK'AI,. i' ;- Scrratu- Second to iL r Minn. twelftll .!:.-. . . I'.-rt. iclav.). dorsal. - minor, I'ronator.-. Pronators. Mu-cles of Tricep-. Triceps. back and Hrach. ant. Hnich. ant. abdomen. I.c.nir cxti-n- I.OIIK flex- Long flex- sor- of or- of ors of wri-t. wrist and wrist and First clor- h'nuors. finirers. sal. Extensor of Extensor of tliuinh. thumb. In t ri nsic mtisfles of hands. IV. I.fMHAH. \. I.fMBAK. Fsoas. Iliacus. Sartorin-. (,)uad. ext . cruri-. (^uad. ext . < ruri-. Obturator. Obturator. Adductor-. Abductor-. (llutei. Glutei. Bicep- femori.- Semitend. Popliteus. 1 1. S \<"KM.. II I. S \' K \i.. I\'. and \'. SAfKAi.. Sphincter ani et vesica 1 . I'erineal muscles. Reaction of Sensory Nerves. Just :is the reaction of the neuro- inu-culur :ipp;tr;it us to cleft ric stimulation is cvidencc'd by muscular f on' r;ift ion, so the reaction o\ the sensory neurons is made known by sensations. In practical \vork, since mixed nerves are usually in- volved, the two sets of phenomena are constantly present. As is the case v.ith muMMilar phenomena, so with the sensory symptoms, '' :' lin ' ;iri tinns in health and disease are known. 'J'hese sensations are thuiiL r ht to be lar ( _ r eh' dependent upon chemic changes, and hence they are u-uallv more apparent at the more definitely chemic terminal of the electric apparatus the cathode. They vary according; to the -i of the elcftrode used, bcinir more distinct with the smaller elect rode, by reason of the condensation of current, also with the nature o! the electric force emploved. Thus the sensation accom- panvintr ' ; ' u-e of the mild L r alvamc current is usiialk- described as 1 1 at of creeping or prickling more nearly dcscribos the normal -< n - iinluceil bv the mild faradic current. A further ELECTRICITY IX DISEASES OF THE XERVOUS SYSTEM 405 variation exists if different solutions for contact are applied, due to the dissociation of different ions. 1 Thus, if ordinary salt solution bo employed, the sensations are more active at the anode, since the dissociated sodium ions enter at that pole; while if sodium carbonate be used, the CO a ions entering at the cathode cause a "'router amount of sensation at that pole. The contact, whether complete or partial, also alters the sensation some- what, perfect contacts being usually much less painful than imperfect ones. Alterations in the rapidity of interruption make a grout differ- ence in the sensations produced on the skin. Single shocks are often extremely painful, oven apart from the muscular effects produced. When the interruptions commence to be more rapid than fifty to the second, the sensations cease to bo individualized, fusion takes place-, and with still more rapid interruptions a pleusunt, smooth glow may be alone experienced, or with more rapid interruptions numbness or anesthesia may be produced. Leduc's currents for local anesthesia are particularly pleasant in application. Protopathic and Epicritic Sensibility. An extremely important, if not epoch-making, research of Head- has opened up an entirely new and wide field for investigation with reference to the electric excitability of the sensory nerves, and has enriched clinical neurology with a new classification of sensory nerves heretofore unrecognized. Thus he has described two sets which he has termed the epicritic and the protopathic sensory systems. These show marked differences in their response to electric stimulation, and our present accounts of sensory nerve phys- iology with reference to electric stimulation will receive an entirely new series of interpretations. Head's views concerning these two sets of sensory nerves may be briefly summarized us follows: Ordinary sensations of touch are not simple and primary, but consist of at least two forms of sensibility, which have been termed by him protopathic and epicritic, and which sensations are dependent upon two distinct systems of fibers. He was led to this differentiation by a large series of studies on peripheral nerve injuries, and subjected his findings to an exceedingly critical control by operating upon a cutaneous nerve of his own arm. The processes of degeneration and regeneration wore carefully studied, and the modifications in sensibility and electric reaction made the basis of an elaborate monograph. As protopathic sensibilitif he describes that form of sensibility which can produce changes in consciousness, but which is incapable of causing a quantitative change apart from the area studied. The position of a point stimulated can be appreciated, and each stimulus causes a widespread radiating sensation, not infrequently referred to parts at a distance. The return of protopathic sensibility to a part, after its loss, brings a cessation of all those destructive changes in nutrition that occur in parts whore the skin is insensitive. Ulcers cease to form, and sores heal as readily as on the healthy skin, although the parts remain insensitive to all higher forms of stimulation, such a< liii'ht touch. After an affected part has remained for a variable period in this condition, it begins to become sensitive to light touch, and degrees of 1 Sec Sanchez. La theorie des ions on elect ririte medieale, Nantes, 11)02; Leduc, lonization Modicales. Monographies Medieales, liU)7. 2 Brain, 1 !>().). See also his previous and subsequent papers. 30 MEDICAL ELECTRICITY AM) ROXTCKN HAYS temperature which produce the sensations called warm and cool on the normal skin are again distinguished correctly one from another. With the gradual return of sensation it again becomes possible to discriminate two points touching the skin at distances more nearly normal, and thy widespread radiation, so characteristic ot the first stage of recovery after the severance of a peripheral sensory nerve, ceases, and is replaced 1 iy an increasing accuracy of localization. It is for this form of sensation that Head has propo.-ed the term t ]>icritic. Head comes to the general conclusion that the sensory mechanism consists of three systems: (I) Deep sensibility, capable of answering to pressure and tot he movements of parts, and even capable of producing pain under the influence of excessive pressure, or when a joint is injured. The fibet> subserving this form of sensation run mainly with the motor nerves, and are not destroyed by division of all the sensory nerves of the skin. (II) Protopathic sensibility, capable of responding to painful cutan- eous stimuli and to the extremes of heat and cold. This is the great reflex system, producing a rapid, widely diffused response, unaccom- panied by an\' definite appreciation of the locality of the spot stimu- lated. (III ) Kpicritic sensibility by which we gain the power of cutaneous localization, of the discrimination of two points, and of the finer grades of temperature called cool and warm. With reference to their distribution, the entire body, without and within, i- supplied bv the protopathic system. The fibers of this sys- tem in the skin may be spoken of as somatic, those of the internal organs as visceral, protopathic fibers. Thus one should speak no longer of the afferent sympathetic system, but of the protopathic supply of t he internal organs. Another set of fibers peculiarly associated with impulses of niove- 1 '!.' and of pressure exist in connection with the Paccinian organs. !'. the bod} and limbs an analogous system is found, peculiarly liable to pressure, to the localization of movement, and to the appreciation ot posit inn. The fibers in this system run in conjunct ion with the motor e>. In addition to these two systems, which are distributed to all parts 1 ' t he body wit hin and wit hout , the surface of the body only is supplied e epicrit ic system. This endows the skin with sensibility .: ' tniich. To the impulses conducted by this system is due the 1 :.: the position of cutaneous stimuli, of di-ceriumr the two points, and ot discriminating between minor degrees ' ' , i-n :. and other -pecial attribute- of -ensatioti. The fibers '<): ' more ea>ily injured, and regenerate more -lowly rotopathic sv-tem. Thev ale evidently more highly roach more nearly to the motor libers which supply .' ' !- in the time required for their regeneration. i'-' d iffe retire in t hese t wo syst ems In elect ric st imula- rni pied currents. I 'rot opal hie sensibility does not iy - ;i <'ii currents whose duration i- less than ().(>f)2 - ' /'lent 1 v current waves having that du rat ion or less li i- more or less uevnui oi painful impres- impul-c decreases, thouu'h they are still felt ELECTRICITY IN DISEASES OF THE XKUVOUS SYSTEM 407 ,S\ n.sor// AYnr Reaction*. These may be determined for the galvanic current by means of a wire brush attached to the cathode. The anode, usually a wet sponge, being placed in the hand or on the sternum. The quantity of current which is regulated by a rheostat in series or by a shunt gives the figures for minimal pain reaction. The varying do- grees of skin resistance render this method irregular as to results. Testing by the faradic current is done by the examining electrode, and the strength determined by the movement of the secondary coil on the primary. The amount of separation of the coils affords a measure of the strength of the current necessary to produce minimal sensations. Krb's table of normal faradic excitability is given as follows: ,, FIKST SF.NSATION MAUKED PAIN PLACE OF EXAMINATION. SEPARATION OF COILS. SEPARATION OF COILS. Check 200-220 mm. 120 mm. Neck i 1SO-220 " 120 " Ann 200 mm. 120 " Fort-arm 190 " 11.") Dorsiim of hand 17.") 110 Tip of fimrer 125 " ' les> regular segmental repre- sentation in the periphery. Klectric testing for distribution of sensa- tion has not advanced, so far as practical clinical purposes are concerned, to the same degree as motor tests, but a careful study of these segmental areas in the skin affords a very important means of diagnosis of both peripheral and central lesions. The spinal s^menta! distribution of the sensory nerve areas do not at all < oincide with the peripheral distribu- tion of the sensory nerves. (See Figs. l>07. 30S, oO<), and Plate !).) 408 MKDIC.VL KLKCTHH'ITV AND RONTGEN RAYS Nerves of Special Sense. The reaction of nerves of special sense is individual ami specific. Klectric stimulation of the olfactory nerve is of lit tk- known practical value. The sensation of the smell of phos- phorus is often given as an approximate description of this reaction sensation. <>l>tit'nl stimulation results in a sensation of a flash of light. Ac- cording to the direction of the current, certain differences have been observed, but marked individual variation undoubtedly exists. C'ath- ui< i- ! li:i*_dii to give a reddish flash, and anodal closure' a bluish lien,er lias constructed special formulas for the reactions of rve r-t imulai ion. (V and A< ) over the closed eye, he states, ! << pt ion cit ;i li^ht central disk, surrounded by a narrow fainter ( '< ) ami .\(' cause a weaker perception in an inverse order. stimulation of the eye with strong currents is not without its danger-, blindness, presumably from retinal hemorrhage, having ported hv a number of observers from Duchenne's time to the ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 469 present. From a diagnostic standpoint optical electric testing has given few definite results. Auditon/ stimulation requires strong currents and results in per- ception of sounds, as of whistling, blowing or buz/ing, being most pronounced to (V, less so to AO, A('l and CO give no results in health Many individuals give no reactions whatever. In pathologic states, particularly in perforation, the reaction is usually more pronounced, Auriculotemporil 3 V. Sm.lJ occipital C. P. Lateral brunches of intercostal Posterior tibial S. P. Fin. 30S. Cutuneoi fttT Flower). constituting a distinct hyperesthesia of the auditory nerve. In some instances of hyperesthesia ATI and ('(). which normally give no re- sponse, may do so. Loss of auditory excitability may be encountered, and an inversion of the formula has been noted in rare cases ot inexact significance, and what is known as a paradoxic reaction is known in which the opposite ear reacts, while that to which the electrode is applied does not respond, or only feebly. Voltaic vertigo is described ()tl l ); 'g'e 39">. 470 MKDICAL KLKCTKICITY AND RON'TGEN RAYS (inxtatnrii perception may he aroused by elect rie stiinuhition, both \vh<-n 1 he tongue is si nnulatcd and when t lie elect rodrs are applied to tin- back oi the neck. One of 1 he author's patients always noted a metal- lic taste when electrodes were applied to the forehead and epigastrium. C.IV c.v C.VI Stiniuliilion bv the anode causes an acid metallic taste; bv the cath- od<-. an kaline bitter taste. Such LMistatorv seii-ations mav be arouserl liv minimal currents and ma\' be subject to loss. DISEASE OF THE PERIPHERAL SENSORY NERVES Anesthesia is brst treated bv a faradic brush electrode. DIAGNOSIS AND TREATMENT OF DISEASES OF PERIPHERAL MOTOR NERVES AND MOTOR CENTERS Palsies of Cranial Nerves ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 471 often involved centrally, although following many toxemias the per- ipheral distributions of the third, fourth, or sixth may be affected. Ocular Muscles. There are many difficulties surrounding the investigation of the eye muscles. The sensitiveness of the conjunctiva and cornea, the delicacy of the retina, and the deep seat of the eyeball itself all make the study of the ocular palsies difficult and exasperating. The intricacy of the innervation plays an important part as well. It is convenient to consider the third, fourth, and sixth nerves together, since they are so closely allied in their functions. The third nerve has the widest distribution, supplying all the external muscles of the eye save the superior oblique, which is supplied by the fourth, and the external rectus, which is supplied by the sixth nerve. The voluntary part of the levator palpebne superior is also supplied by the third; the involuntary part, by the cervical sympathetic nerves. The third nerve also goes to the interior of the eye, supplying, through the ciliary ganglion, the ciliary muscle and the sphincter pupilhe. The ciliary ganglion is at present considered by a number of scholars to be the peripheral motor nucleus for the sphincter pupilhe. Complete paralysis of the third nerve gives ptosis, external strabis- mus, inability of the globe to move upward, straight down, or decidedly inward. The pupil is dilated and does not contract on exposure to light. Complete paralysis is rare 1 . Hysteric paralysis is not unusual, but so far as the ptosis is concerned, is usually differentiated from organic paral- ysis by the absence of an overacting levator of the other side. Electric tests are unavailing in determining the peripheral or central character of a third-nerve paralysis, although the longitudinal reaction has been obtained in levator palpebne paralysis. In nuclear lesions it is important to bear in mind that the orbicularis oculi is also involved. Transient ocular palsies, such as occur in oph- thalmic migraine, should not be confounded with true ocular palsies. Foiirth-ncrn' /;rm;///.s/x causes a characteristic diplopia, which is not capable of electric analysis. Xi.rth-nrrrc pdralt/xix paralysis of the external rectus causes a characteristic and isolated internal squint. Tht-rnpi/. These ocular palsies may be treated by electric stimula- tion, but it cannot be said that the treatment is always satisfactory. Only after thorough antisyphilitic and antirheumatic treatments have been persistently carried out is one warranted in trying elec- tricity. Even in hysteric ptosis one is not warranted in abusing the electric treatment for fear of excess of suggestion. Electric stimula- tion of the levator palpebne is at times useful. Such electric stimula- tion as recommended bv Everthain and Salomonson should be done by a button electrode applied about }- inch under the highest part of the supra-orbital arch. The method followed for treatment of the ocular palsies by elec- direct application of the at the nap* 1 of the nee I sponges may be uccessful result: M'luihry. Bulletin ofiiciel de la Socicte Frunraise d'elec-trot lirrupic, n 190o. 172 MKOH'AL KI,K(TKieJTY AND HONTCiKN HAYS Facial Nerve. This nerve is more frequently subject to disease than any other cranial nerve. The lesion itself may be treated by bilateral stimulation with galvanic currents. An electrode about 2 cm. (;' inch) in diameter is placed in each auriciilomast oid fossa, the negative electrode being on the affected side. A current of (> or S ma. is allowed to flow for five minutes. Flectricity may be used to maintain the nutrition of the paralyzed facial muscles and hasten the return of power. In cases in which faradic excitability is present the paralyzed muscles may be exercised by faradic currents and a trophic effect upon them may be secured by galvanic currents. One of the best ap- plications is the de Watteville, or galvanofaradie current, rhythmic- ally varied in intensity and direction by the rhythmic rheostat and pole-changer or some similar apparatus. Tin galvanic current has a maximum intensity of ."> or 6 ma. and the faradic coil has coarse wire and slow interruptions and a strength of current sufficient to cause contraction of the facial muscles. One electrode is held in the hand, and the other is applied for about a minute to the motor point of each of the paraly/ed muscles. In the absence of special apparatus the galvanic and faradic currents may be applied separately. Stimulation by isolated induction shocks or by condenser discharges are more valu- able in treating the muscles of the face than those elsewhere. These muscles tire short, and do not have the inertia of a considerable weight to overcome. The abrupt contraction produced by the applications i- not. therefore, so undesirable as it is elsewhere. /.*i>/iih(l induction >7mr/,-.s- cause contractions which are much more -uddeii in onset and subsidence and much briefer in duration than physiologic contract ions. They are not generally desirable in elect ro- mechanotherapy, but perhaps are all right for exercising the small muscles of the face which normally do not have much resistance to be ' iTcome by i heir <( >nt ract it m. I'aralvsis of the entire innervation of the seventh nerve is not com- mon, save in central lesions: paralyses of separate branches are very I ' is a highly complex nerve, and is probably not a pure mot or n<-rve, bill has a sensory root as well, probably, as Hunt 1 has shown, ate ganglion. The typic involvements of the facial nerve 1 ( Mitside of the stvlomastoid foramen, leading to Bell's -is: _' within the Fallopian canal: (!>) between its emergence ion- and the geiiiculate ganglion, and (1) within the pons. /! /nil.-/. eight months is not too long for a severe case to persist and ree-over. Tin Static Ware Curnnt tor Facial J'aral;/*/*. Win. Martin' applies 1 Amcr. .Tour. Electrotherapy and Radiology, vol. xxxvi. No. 0, September, lit is. P. '-'.".I. 171 MKIHCAI. KLK( TKHITY AM) HO.NTCKN HAYS a mrtal electrode shaped to fit the side of the face in front and behind t lie ear. Massey modifies this by using the bull electrode. In long-standing intractable cases anastomosis is useful, either through the hypoglossal or the spinal accessory. Following such anastomo>is further electric stimulation is advantageous. t'Ji In lixiun* <>f the facial within the a of service in these cases as well, but does not , as a rule, L r iv<- :.- hopeful results. These nuclear lesions are usually syphilitic or met asvphiht ic, in the latter case often appearing very early in tabes and in general pa re-is. In these latter affections, naturally, electric tl'eatn ent ol the facial ner\'e is useless. tiiltiti ml l-'arial I'als'i. This is a rare affection, being due most mien to syphilitic ba>ilar meningitis, or to alcohol, diphtheria, or 1 edia. l)ouble geniculate affections have not yet been I'lhed, but are possible. In certain mvopathies a pseudo-double tacial pal-v i- encountered. In ' ol alcoholic, ilipht heric, or olitic origin, the general proc-dur<- advocated for unilateral palsy are applicable. Vagus Nerve. Paralysis of the soft palate and the larynx result ' ' ' IILTUS. In paralysis of the sol t palat e \\\r react ion of deirenerat ion i~ -ometimes encountered. esj)ecially m diphtheric neuritis. 1 .Inurii:il I'f N'-rvMii- ;,ipl Mcnt;il I)i.-c;i-c, vol. \\xiv, p. 7^!. I''d)rii;iry, 1H07. ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 475 In such a condition electric treatment is of certain avail, particularly in shortening; the period of regurgitation of food through the nose. In paralysis of the vocal cords from recurrent laryngeal involvement electric stimulation is beneficial. Adductor palsy is bilateral; the patient suddenly loses the voice, yet can talk in a whisper; there is no stridor, and laryngoscopic ex- amination shows the cords to move outward normally. Strong faradic shocks often make an immediate cure of hysteric aphonia. (Set' Hysteria.) In laryngeal paralysis due to tabes electric therapy is practically unavailing, nor is it palliative even in laryngeal crises. Spinal Accessory Nerve.- Involvement of this nerve produces change's in the sternomastoid and trapc/ius. causing the head to be held toward the opposite shoulder, with downward and outward displace- ment of the scapula. The scapular displacement is modified greatly if an attendant lesion of the cervical roots be present. Surgical lesions are mostly responsible for involvement of this nerve. Treatment is to be carried out according to the procedures already outlined for paralysis of the facial nerve. Hypoglossal Nerve. Paralysis of the hypoglossal results in hemilingual atrophy. This is a comparatively rani disorder. It may be of central or peripheral origin, in the former case depending on syphilis, tabes, or paresis. Tumors, stab wounds, basilar meningitis, trauma with marked sudden rotation of the neck, may all bring on peripheral palsy. There are no particular features attending the electric treatment of hypoglossal palsy. It is rarely isolated, as syphilis is the most fre- quent cause, in which case it is accompanied by associated palsies of the contiguous nuclei. The peripheral cases frequently recover without any treatment, although electric stimulation hastens such a result. Bulbar Palsies As a result of acute or subacute poliomyelitis, several of the medullary nuclei may be involved. This is particularly true in what is known as glossolabial paralysis, which is a mixed paralysis, involving, for the most part, portions of the nuclei of the seventh and twelfth nerves. The electric phenomena observed in examinations in this disorder, whether in the acute or the chronic stages, an^ usually of a mixed character. There are healthy fibers interspersed with unhealthy fibers, the result being that an indefinite reaction of degeneration is obtained, some of the fibers retaining the normal reaction, while ad- jacent fibers present typic reaction of degeneration. These mixed reactions are found in practically all the atrophies, especially of the central type; that is. when the motor cells in the medulla or spinal cord are involved. They are less often present in the paralyses of a peripheral type, and, therefore, are of a certain amount of diagnostic significance. The electric treatment of bulbar palsy offers a considerable field of operation. The best results are usually obtained in the distribution of the seventh nerve, although it is not impossible to obtain SOUK; beneficial results in other nerve regions. It should be borne in mind that bulbar palsy may be found in a 47C) MKIHt AI. KLKCTHICITY AND K(")NT(iKN HAYS number of conditions. It in;iy be hysteric or infantile, or it may be due to unknown ami unappreciated pathologic conditions, but its ino^t frequent occurrence' is, as has already been stated, in poliomye- litis, in chronic progressive muscular atrophy, and as a complication of amyotrophic lateral sclenis. Attention has already been called to the differentiation of true bulbar pal-y from >o-called pseudobulbar palsy, or myasthenia uravis. Here the inya-theilic reaction is usually sufficient to mark it. It should be borne in mind that electric treatment of bulbar palsy is not without very distinct danger. The ordinary faradic or galvanic irritat ion. such a> is practised in the treatment of ordinary paralyses, iias at times led to di>a>trous results, and even to death. Oppenheim has called particular attention to this danger. Central galvanization, however, is of value. The exact indications for the electric tr-atment of bulbar palsy an- not yet defined suitably, and up to the present time \ve have no really reliable information hearing on the therapeutic usa^e of other forms of elect ric energy in this affection. Paralyses in the Cervical Region As i- well known, the spinal muscular types of paralysis have a re which is characteristic. If the motor neuron is involved at its center, namely, in the iran.ii:! ion-cell within the anterior horns of the >pmal cord, the mu-cles involved are usually affected from the outset. They acquire the full and maximum amount of paralvsis very rapidly, and recovery i.- gradual and slow. In the peripheral paralyses. /. <., when i he motor neuron is affected through n> distal distribution apart from severance or acute pressure the onset of paralvsis is usually slow and Liradual. and atrophy becomes apparent only after -ome time. In both tvpes the limb, if the whole member is involved. - helples:- never stiff. The joints are relaxed and the articular -urfaces are u-iiallv separated bv the weight of the member. The ies are flabby and relaxed and show little or no myotatic irrita- ' . The tendon reflexes are partially or wholly irone. Their per- -istence m the face of a flaccid paralvsis usuallv means the implication of tin i-ni |)yramid:il ' racts. Such lorn - i paralysis are common m poliomyelitis, acute and votroplnc lateral sclerosis, in tumors and hemorrhages ' n the i-ord. m embolism or thrombosis leading to softening, in -:_'<- oi myelitis, in syrin in the \\-irious seu~- ' .' ' ' !', en in t ;: hllhi I 1 form. (See p. Ill I . Functional or Organic Paralyses. It remains first, in makintr VMS, eit her of t he upper cervical t \ pe or of 1 he lower 1 n ii 'inipleii'ia or paraplegia i- pre.-eiit. to determine i- is oriranic or functional. The differentiation niosl c;ises comparat i\'el v simple, yet in a lariz'e no me;ms an easv matter. Tin- is particularly ': early pal>ies o| disseminated sclerosis, where Aeakness verv freoiientlv simulat<' a like con- ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 477 dition ill hysteria. As a rule, muscular atrophy is not an accom- paniment of functional disease, at least not in the early stages, and the electric reaction of degeneration never occurs in functional disorders unless muscular atrophy is found as a result of many years of disuse of a muscle group. In some of these cases a reaction of degeneration suffi- cient to raise a query may be found. As a rule, the functional paralyse- involve whole groups of muscles, or even whole muscle functions. Involvement of single muscles is usually diagnostic of organic disturb- ance. The differentiation of organic paralysis in the lower neuron type, that is. in the spinal muscular neuron, is a comparatively easy affair, since the features already outlined are usually sufficient to develop a definite diagnosis, but in the corticospinal neuron types, where no atrophy is to be expected, and where the reaction of degeneration does not take place, differentiation becomes ofttimes fraught with diffi- culty. There are cases of hysteric hcmiplcgia and hysteric paraplegia which defy the ordinary positive tests of electric or neurologic examina- tion. In the hysteric hemiplegias and paraplegias, the study of some of the more complicated tendon reflexes offers a clue to diagnosis. The re- flexes most often studied and upon which most reliance 1 may bo placed are those of Babinski and Oppenheim. The Babinxki reflex is almost invariably present in the organic hemiplegias and paraplegias. The Oppenheint reflex has much the same significance as the Babinski reflex. (rrassct's sign, which is less well known, consists in the inability of an organic hemiplegic while lying flat upon the back to lift both the limbs from a table or bed, but being able to lift each one sepa- rately. The reason for this is that the organic hemiplegic, by reason of defects about the pelvis, is unable to fix the bones about the pelvic girdle, and is thus unable to lift both legs at one time. The legs should bo separated so that the one cannot mutually help the other. The hysteric has no difficulty in raising both logs i. c., of course, speaking of the milder typos of the disease in both instances. Certain of the more prominent paralyses of the cervical region will be hero considered. The most important of these are the paralyses of the trapezius, sternomastoid, sorratus magnus. scapular muscles, and deltoid. Certain combined paralyses of the shoulder-girdle, such as Krb's palsy, arc of groat importance, Sternomastoid and Trapezius. These muscles are usually in- volved more or loss in unison, their cell groups lying close to one another in the cord. When both are involved, a central lesion is predicated, although operations about the nock sometimes result in injury to their peripheral nerve-supply. The bringing of tension on the sternomastoid by forced rotation of the head is usually sufficient to demonstrate a change in this muscle. Paralysis of the trapezius results in a marked drooping of the shoulder, since this muscle is of so much importance in supporting it. The scapula is tilted with its upper end away from the median line and depressed, the lower end approaching the vertebral column and elevated somewhat. On raising the arms above the head the outer end of the clavicle becomes visible from behind. Electric treatment bv means of both galvanic and faradic shocks ITS MKDICAL K1.K( THKTrV AM) RONTCiKN HAYS -hould he energetic and prolonged. In surgical cases associated with complete reaction of degeneration in all the libers of the muscle after ten days or two weeks, prompt surgical splicing should he instituted. Kven after months or years the 1 results of surgical severance .may be obviated by surgical intervention combined with electric treatment. Serratus Magnus. Paralysis of this as an isolated muscle is rare, though by reason of the fact that its nerve-supply runs in the sub- stance of the scalenus medius muscle it may be subjected to trau- ma-, particularly in neck operations. The deformity is characteristic. Kxtension iif the anus forward at right angles to the axis of the body causes a marked winu' scapula, the posterior edge appearing as a ridge. \\iih an attendant deltoid paralysis the inability to extend the arms forward makes it impossible to bring out the phenomenon. In testing fur this paralysis Jones recommends that the indifferent electrode be placed in the posterior triangle of the neck and the active electrode applied to 1 he serrations of the muscle. In paralysis of this nerve as a result of infection or pressure (as seen in some special occupations poling boats etc.). electric treatment is Very effect ive. Supraspinatus and Infraspinatus. In paralyses of these muscles extern.-d rotation of the luimerus becomes an awkward affair: writing becomes ditiicult. and the ordinary sewing movements ot pushing a needle in and taking i' out of a fabric are impossible. Atrophy of the muscles causes a ridge of the scapula to stand out prominently. As the supraspinatus lies dee]) beneath the trape/ius. electric reactions are ;:: ; :>-ult to obtain. In obstetric paralysis the suprascapular nerve, uhich -npplies the -pinati. may be involved in conjunction with the circumflex. Klei-tric treatment for these paralyses differs in no essential par- t ic liars from 1 hat in ot her parts of t he body. Deltoid Paralysis. The circumflex, derived from the fifth, sixth, seventh, and eighth cervical nerves, supplies the deltoid and the teres Inability to raise the arm is the chief siirn in deltoid paralysis. iliscle wastes and the shoulder flattens. The acromion process becomes more prominent, the humerus at limes hanging away from the joint. Paralysis oi the deltoid may be partial or complete, and cases are record, e.Mction of degeneration in parts of the muscle, other normal reactions. These isolated paralyse- result from More particularly blows, trauma from axillarv pads. j on the arm at birth may all involve the circumflex, . ,- . .': ich nives ii origin. ' rni'j of the teres ininor is difficult to carry out. Testing -at isfacl ' irv. I' r;d the (jelioid i- UHlallv an obstinate affair. Klectric \ci lent results, but i he-e i> ffe< | iient iv a residual !> foi vears all at tempts at rest it in ion. Combined Palsies. The combined palsies due to trunk lesions iied from those \\hicii io||o\\ a legion of the roots /-.' //, /i'il.- . . \ )i-|i ical ions of i he -In mlder- head of the humerus should press forward. i;i'-pre;id and -erion- paralyses involving one or Li brachial plexus. A diagnosis of the nerves p : ' : a I v/ed mu-cles. ELECTRICITY IN DISEASES OF THE XEKVOUS .SYSTEM 479 Reaction of degeneration soon develops in ihose muscles most implicated, especially after the period passes when a stage of inter- stitial edema is apt to cause hard and stiff muscles, for in such a con- dition reaction of degeneration is difficult to obtain. In many cases of neuritis which may cause extensive atrophies the presence' of severe pain may interfere with electric and testing electric treatment for some time. Erb's Paralysis. This consists essentially in a lesion of the roots of the brachial plexus, due to a severance or tearing of the root-fibers as they emerge from the spinal cord. As a rule, the chief damage is done to the fifth and sixth cervical nerves, although only the fifth, or only the sixth, or even the seventh, may be disturbed, and the mus- cles most widely implicated are the deltoid, biceps, supinator brevis, brachialis anticus, and the spinati. At times only the deltoid is in- volved. There may be associated anesthesia on the outer aspect of the arm, due to the implication of the external cutaneous. The position of the arm in Erb's obstetric palx;/, called obstetric because so frequently induced as an obstetric accident pulling of the arm in delivery with stretching and tearing of nerve-roots is very characteristic, ('specially if more than a mere paralysis of a few fibers of the deltoid is present. The arm usually hangs helpless by the side, the forearm being turned inward and backward, so that the palm of the hand is turned backward and even outward. The electric reactions are of interest in showing the distribution of the implicated fibers, since the biceps, coracobrachialis. and brachialis anticus are supplied by the musculocutaneous, the deltoid is supplied by the circumflex, the supinator longus is supplied by the musculo- spiral, and the spinati by the suprascapular nerve. In traumatic affections of the musculospiral, and in the neuritides, particularly that of lead, the supinator longus escapes, since 1 the spinal-cord cell-group fibers enter the plexus above the point of fusion that makes up the musculospiral nerve. Electric testing at Flrb's point i. c., in the neck, about one inch above the clavicle, and a trifle external to the outer border of the sterno- cleidomastoid, is capable of throwing this entire group of muscles into activity, and when obstetric palsy is present, stimulation at this point is unavailing. In Erb's palsy, also called Duchenne-Erb palsy, other muscles may be involved, and a great degree of complexity is known to occur. The electric treatment of Erb's palsy by means of both galvanic and faradic currents should be continued for a long time; many mild cases recover spontaneously without treatment, but in the severer cases electric stimulation is of immense service. Injury to brachial plexus, as by dislocation of the shoulder. W. Mart in 1 tests by static wave current, plexus and ent ire length of branches, and treats by wave current, high-frequency static sparks, radiant heat and light. Musculospiral Paralysis. This nerve i- most frequently involved outside oi the plexus, and causes a lo.-s of power in the extensor.- of the forearm and wrist and the supinators. The wrist drops, the finuvrs are flexed but can be extended, if the proximal joint is flexed, by the interossei and the lumbricales. Extension of the elbow is impossible; 1 AMHT. Jour. Electrotherapy ;iml K;tuy, vol. xxxvi, No. 1, p. 2.1. IM) MKDK \L KLK< TKK ITY AM) ROXTGEN KAYS atrophy of the extensors causes the forearm to shrink very materially, while t he bone- of t he wrist become very apparent . Involvement of the biceps points to mjiirv above the middle of the arm. and supination i- then moderately well performed. If supination is entirely .u'ono, the nerve is usually implicated below the middle of the arm. Sensory dis- t urbaiices are frequent . I he commonest cause of musculospiral paralysis is pressure duo to -leepim: on the arm. or with the arms hunting over t ho back of a chair, or poor adjustment of a crutch. Reaction of degeneration in the various muscle- innervated by the musculospiral L- sufficient to make a diagnosis of this palsy, and TO distinguish it from the wider implications of the brachial plexus in Krb's palsy. Treatment of musculospiral paralysis by the iaradic and galvanic current.- i- of iM'eat service, save in those c.-ses where actual section' of the nerve has taken place. The electric currents are of service after the nerve has been united by suture. Median Nerve. The median supplies the pronators. the flexor carpi radialis. the flexor- of the tinkers, and the abductors and flexors of the thumb, and the 1 wo radial lumbricales. which flex t he first phalanx- It arises from all the roots of the brachial plexus. This nerve may be involved above its muscular branches from wounds in the forearm, fracture of the ulna and radius, injury at the back of the elbow, from pre-.-ui'e of a crutch, or from injury to parts of the plexus. Plexus injuries will not irive isolated median-nerve involvement. The chief symptoms of involvement of the median nerve consist in the lo>- of ability to flex and to pronate the forearm; this latter is a relative rather than an absolute loss. Flexion to the ulnar side of the wriM is po.--ible. The hand cannot irrasp anything well, and the thumb cannot be brought into apposition with the tips of the finders. It cannot be abducted either. Pain is a frequent symptom, and there is a characteristic anesthesia pictured in \\orks on neurology. Injuries to I he nerve in the wrist causes a paralysis, limited to i h( movements of the finders. Atrophy ot the thenar eminences is 1 he median nerve is frequently affected by toxic agents, with result- euritis, although this is rarely isolated. Treatment of paralvsis from median-nerve neuritis, or of that dui to injury of the nerve-trunk, by mean- of electric currents differs no (-- -mial re- pec t from the methods to be pursued for other nouri- tide- oi paralvsos. If electric testing shows the reaction of deuenera- t ion l o be limit ed to ! he (list rib lit ion ot the median, it is hlii'hl v probable ' the injun i- ([ue to Mime mechanic cause. Ulnar Nerve. This is derived from the brachial plexus, and is io the flexor profundus dimtorum. flexor carpi ulnaris, all oi the little finder, the mtero.-sei. two ulnar lumbricales, nd the flexor brevis polbcis. Manv of the muscles '.'. :. upplied in part bv other nerves, hence there is not a \ characteristic deformity, the claw hand, is a usual ,->is. The deformity i- '_;eneral. but the third and ' affected. I he ulnar IM: i- particularly e.xpo-ed to damage bv reason of ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 481 its exposed position. Wounds in the forearm, at the wrist, fracture of the ulnar or radius, dislocation, fractures or contusions at the elbow, all may lead to injury of this nerve. Isolated neuritis is known. Head, Rivers, and Sherrington have shown that the ulnar nerve carries epicritic fibers of touch to one and a half finders, and the ulnar portion of the palm and dorsuni of the hand. It carries sensation of pricking from the little and ring finders and the palm, save from the thenar eminence, and all the dorsuni to the ulnar side of the middle of the middle finder. If the nerve be divided, there is loss of sensibility to cotton- wool over the entire little finder and half of the ring finger, with the same limited area in the palm of the hand. There is also an area which is insensitive to pin-prick over the entire little finger, and a por- tion of the palm at times very limited, at other times coextensive with the area lost to light touch. Spinal Motor Centers and Motor Nerves of the Lower Extremity These are less often involved in injuries than are those of the upper limbs, whereas the gray matter in the cord is more apt to be the seat of disease than in the cervical region. In acute poliomyelitis the muscles of the lower limbs are usually affected more than those of the upper extremity, this being particularly true of the peronei. A short consider- ation will be given to the chief paralyses of the thigh and leg. Their treatment may be considered in one paragraph. Obturator Nerve. This is derived from the third and fourth lumbar nerves, and supplies the adductors of the thigh. It is a rare form of palsy, chiefly causing difficulty in crossing one leg over the other and in spreading the legs apart. The disorder is known to follow difficult child-birth, but is usually a transitory affection. Anterior Crural. Disease or injury to this nerve in different parts of its course, if within the pelvis, may give rise to loss of power to flex the knee and loss of hip flexion. If outside of the pelvis, flexion of the knee alone is involved. An anesthesia of the entire thigh, save a long V-shaped area in the back of the thigh, is present as well. Sciatic Nerve. If this nerve is involved above the middle third of the thigh, the flexors of the knee, the extensors of the hip, and all the muscles below the knee are implicated. If below the upper third, only the muscles below the knee are involved. Paralysis of the sciatic is a comparatively rare affection. Sensory disturbances are, however, very common, and primary neuritis or sciatica is one of the commonest of neuralgic or neuritic affections. Peroneal Paralysis. Involvement of the external and internal popliteal nerves causes great loss of the ability to get about. The tibialis anticus. long and short extensors of tin' toes, and the peronei are all involved in external popliteal injuries. The resulting deformity is foot-drop, with after-developing talipes equinus. due to the unop- posed action of the gastrocnemius. As the external popliteal is super- ficially located it is injured by pressure, by fractures of the fibula, and is occasionally diseased primarily. The internal popliteal supplies the tibialis posticus and poplitetis, as well as the chief muscles of the back of the leg. the long flexors of the toes, and the muscles of the sole of the foot. In injury or disease of 31 482 MEDICAL ELECTRICITY AND ROXTGEN RAYS this nerve the foot cannot bo extended, and tho leg cannot bo inwardly rotated when flcxod if tho poplitous is affected. Injury of the internal popliteal takes place in extensive fractures of both bones of the leg. Plantar Paralysis. Involvement of the external plantar nerve causes a loss of power in tho interossei, the adductor of the big toe, tho two outer lumbricales. and the accessory flexor of the foot. Walking is interfered with, the spring having departed from the foot. The toe is apt to strike, and stumbling is usual. The special sensory area is sharply limited. Injury to the internal plantar nerve brings about a paralysis of the short flexors of the toes, the muscles of the big toe, save the adductor, and the inner lumbricales. It causes a somewhat similar, although much less marked, difficulty in walking. Treatment. The electric treatment of these palsies differs in no essential respects from that already outlined in previous paragraphs. In general, one can derive considerable assistance, so far as prognosis is concerned, from the electric reactions. The degree of degeneration which has occurred can bo determined, and also the probable length of time necessary for recovery. In all these paralyses, of the lower as well as the upper extremities, the same general rule must be followed as that already outlined. It is necessary in all cases to wait ten days to two weeks for the sake of a diagnosis, as well as a prognosis. In the case of patients where neuritis is found, or in whom painful nerve- trunks may be present apart from neuritis, such as may be due to the irritation of the moninges, too early electric treatment, or even the use of electricity for diagnostic purposes, should be deprecated by reason of the extreme pain which may bo induced. If pain be not a prominent feature, the electric reactions should be tested as early as the second week; any earlier is valueless, so far as diagnosis is concerned. In general it may be said that if, at the end of from two to three weeks, we obtain a typic reaction of degeneration, it is probable that the paralysis will persist for at least three months, and may oven be found at a much later date a year or so. If, after three months, no distinct improvement has been observed, it has been generally held that no hopeful outlook can be maintained. This, however, is not the case, for continued and unremitting attention paid to the chronic paralysis will almost invariably result in the restoration of considerable power, at least, and the general rule that if reaction of degeneration is present in a muscle at the end of three months such muscle is doomed, is in need of distinct revision. This may oven be said of those reactions of degeneration which are found in paralyzed groups, even after a year, although m such cases the outlook is more gloomy. If a partial reaction of degeneration is found, or mixed reaction, '})< chances are much better, and if in the milder cases of neuritis or ipheral pal^y due to injury other than actual division of the norvo, reaction of degeneration occurs, the patient will probably uer in ;rom eight to ten weeks. reaction is simply one of a lessened contractility to faradism f recovery are good, the patient usually -omewhat diminished in strength, ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 483 the lower limbs have already been outlined and are further discussed in the paragraphs on Electromcchanotherapy. All electric treatment should, if possible, be associated with massage and exercises. Hysteric Paralysis Faradic currents are used to cause contraction, while at the same time the patient makes a voluntary effort. This forms a sort of re- education. Sensory hysteric paralysis always yields to faradism, with rapid interruptions and a brush electrode. Hysteric amaurosis or more or less contraction of the field of vision are treated by faradization with one of the electrodes applied to the eyelids. Hysteric aphonia is treated by faradism, and usually is quickly cured, though one case of the author's resisted all kinds of treatment, including hypnotic sug- gestion. Hysteric vomiting is treated by galvanic currents. Hysteric Contractures. Faradization with a brush-electrode ap- plied either to the contracted muscle or to its antagonist, and galvanic current with the negative electrode applied to the contracted muscle, bring about a cure. ELECTROMECHANOTHERAPY This means the application of electricity to produce muscular contraction. It is useful when, for any reason, it is impossible or undesirable for the patient to exercise his muscles, any particular muscle, or any part of a muscle. It has, to a greater or less extent, the same beneficial effect upon the nutrition of the muscle and upon the general system that natural exercise produces. Muscular contraction is accompanied by oxidation, generation of heat, and complex processes of tissue activity. It must be borne in mind that electricity has a specific tonic effect upon muscular as well as other tissues, which it exerts whether mus- cular contraction is produced or not. This direct effect is more de- pendent upon the quantity of electricity passed through the muscle than upon abruptness in the change in the strength of the current. The direct effect upon the nutrition of the muscles is produced chiefly by galvanic and sinusoidal currents, and is obtained by forms of ap- plication which do not necessarily produce muscular contraction, and also in cases of degeneration in which no contraction can be produced by any form of current. Confining attention strictly to eletromechanotherapy (the therapeu- tic production of muscular contraction by electric stimulation), we find it indicated in most muscular paralyses without marked reaction of degeneration. It is sometimes important to avoid stimulation of the antagonistic muscles which respond more readily than the paralyzed ones, and would lead to increased deformity. If this occurs from uni- polar stimulation with the indifferent electrode upon the back, it may often be prevented by placing both electrodes on the paraly/ed muscle. The limb should be placed in such a position that contraction of the muscle stimulated will produce a normal movement. \ ery often some power of voluntary movement is present, and it is -1S4 MEDICAL KLKCTKK ITY AM) KO.NTGKN HAYS desirable to apply electric stimulation to assist individual attempts at voluntary movement . As improvement takes place the factor of movement against resist- ance is to be introduced, making the effect still more like the physiologic effect. Too lonii treatments will produce fatigue in the same way as too prolonged natural exercise. Thi> is to he avoided. Method for r.fv/r/Wm/ i>f I he muscles t he posit ive elect rode should be near 1 he nerve- cenliT. and tin- negative electrode should be applied to the motor nerve or to the mu-' 1, . Galvanic Currents Modified by Condensers in Parallel.- These are a valuable in \\ tne;ms of applying a ii-elul strength of current without prodiicinu: unnalurallv abrupt muscular contraction.- (paue Mil). Stimulation by isolated induction shocks produce- abrupt muscu- lar contraction-, which are 1 >et ter t han none, but which are less desirable ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 485 than if they approached the physiologic type. It -rives HOIK; of the direct tonic effect of electricity, because the quantity of electricity which passes through the muscle is very snuill. Stimulation by condenser discharges is open to the same objection from a therapeutic standpoint, though the certainty with which each discharge may be measured makes it a valuable diagnostic method. Faradization is the method chiefly employed for elect romeclmno- therapy, but it has the same drawbacks as isolated induction discharges and condenser discharges. The contractions produced by it are not as desirable as physiologic contractions, and the quantity of electricity is too small to produce the direct tonic effect of the current. If the faradic current is employed, it had better be applied with one electrode on the motor nerve or the motor point of the muscle, while the other electrode is on the back or chest or some other indifferent place 1 , and the application be made 1 simply to cause muscular contractions, being sup- plemented by the galvanic current for its trophic effect. The combined effects of faradic and galvanic currents may be ob- tained by either their simultaneous or their successive application. The second method is one by which galvanic currents of any desirable strength are applied for ten minutes from electrodes covering the whole affected muscle, either before or after a series of muscular contractions have 1 been excited by the faradic current. Lewis Jones' experiments show that a faradic coil without an iron core gives currents without such abrupt increase 1 and decrease in strength and produces less abrupt and disagreeable muscular contractions than when the coil has an iron core. Kven so modified, however, the faradic coil produces quite an abrupt beginning and end of muscular contraction, with a period of tetanus lasting from the time the current is turned on until it is turned off. This is not at al! like the physiologic con- traction, and is, therefore, less desirable than the contraction produced by the author's method of rhythmic variation by rheostat and pole- changer, or by the other method of sinusoidal currents with rhythmic variation. Faradogalvanic or deWatteville currents are applied from an apparatus in which the secondary coil of a faradic coil forms part ot the circuit of a galvanic battery. "While it has been stated elsewhere that the polarity of a faradic coil makes practically no difference in the physiologic effects, and that either pole may be used as the active electrode, this ceases to be true when the faradu- and galvanic currents are combined. Figure 1 -$10, 1 , shows the 1 form of the interrupted currents produced by a faradic coil alone 1 . The 1 make or closure 1 e-unvnt is of much less -tretiglh and is in the 1 e>pposite direction from the 1 ctinvnt induceel at the 1 break or opening of the 1 primary circuit. The 1 best results are 1 obtained with a galvanofaradic current. made so that the 1 opeMiing currents of the direction as, and add to the strength proper effect is shown in Fiii'. olO, 2, and in Fig. MIO, :i. The sensation produced by galvanofaradi/at ion is different from that of e'itluM 1 of the 1 component cunvnts separately. Its eftVct is to cause muscular contraction ami trophic stimulation, but applied in 4M> MKDICAL ELKCTUICITY AXI) KOXTCKX KAYS the ordinary way by means of a key that makes and breaks the current abruptly the muscular contractions have the same unnatural character as with the Dimple faradic current. The r' nni/n! of applying faradoyalvanic current* produces muscular contractions which closely resemble physiologic ones, and make- the application agreeable, and causes it to be followed by a sense of muscular power which is most exhilarating and beneficial. It con- E 1 1. \iitlini 1 '- nalvanii-, faradir. and sinusoidal apparatus- piving also galvano- urrent-, and currents; with rhythmic variations si-t.- in ihi' u-e ot a i'/i i/lli in ic rficoxltit on/] polc-cha/if/cr i Fiii. 311, A), ilireciion of the current i.- reversed at regular intervals of from one-hall -ecoiid to two seconds. There are sliding contacts, ; up and down the rheostat liy n small electric motor. At a certain -; _;< the Lialvanometer \\'ill show thai no current is passing ihioii-i: ti.t- p; ;. in. '1'hcii. as 'he rheostat ix'sistance is automatically ri-duccd, liii' c . rent gradually lieuin^ io llo\\' in one direction, and in- .':;. I ") ma., [lerhajts, permitte(| by the adjustment 11! anoil in'j rheo-tat and the unvai'yin.u \'olt coni roll<-r. The liet tei' l>e made al t he commencetiient ot t lu 1 treat- iiierii . I r . , it iV j M\>t to beiiin wit h t he weakest possible current. \-arym.i: rhen-tal ha> permitted the maximum low. the current i- lii'aduallv reduced to zero, and is : ' , ia itains an eijiial maximum strength in the op- tio-iti In re n auain ii'raduallv return.- to zero. ELECTRICITY IN DISEASES Or THE NERVOUS SYSTEM 487 Holding two electrodes in the hands, one feels his grip gradually tighten and 'relax, first in one hand, and then in the other, as the maxi- mum current is attained in each direction. All the muscles of each upper extremity are affected by the trophic influence of the galvanic current, and the muscular contraction may be caused to involve as man\- of these muscles as desired by regulating the strength of the faradic current. The application is entirely free from shock and other dis- agreeable sensations. Its alternating character prevents irritation of the skin by the accumulation of ions, and enables one to secure the bene- ficial effects of strong currents without having to use enormous electrodes. A good contact is the chief essential. The contractions closely simu- late physiologic ones. These currents are of great value in peripheral paralyses and in constipation, where the electrodes are applied at either side of the ab- domen. The same picture (Fig. 311) shows also the arrangement for utilizing the 1 10-volt direct current in galvanic, faradic, and deWatteville appli- cations, continuous or interrupted. In the author's apparatus there are three different secondary wind- ings of the same faradic coil, made instantly available by turning a switch indicating loOO, 3000, or 8000 feet of wire. The ribbon vi- brating interrupters regulate the rapidity of the interruptions from the fastest to the slowest, and the two separate primary coils may have the same or different rates of vibration. There is a sledge upon which the single secondary coil may be moved toward or away from the pri- mary coils. The farther away the weaker the current and the physi- ologic effect. Gaiffe's Portable Apparatus for Exciting Physiologic Contrac- tions of Muscles. The apparatus is useful in cases where paralyzed or atrophic muscle's are to be exercised in order to maintain their nutri- tion, but not in cases with the reaction of degeneration. Faradic cur- rents cause muscular contractions which are unnatural in the abrupt- ness with which they begin and end. Voluntary muscular contractions commence gradually, and after attaining their maximum, gradually relax. The apparatus described by Delherm 1 produces contractions of this type by the application of a sinusoidal current, which increases from zero to a maximum strength, and then gradually diminishes to zero. The apparatus consists essentially of an electromagnet which oscillates in front of a dynamo, and causes increasing or diminishing currents in the latter. It is portable. Figure 1 312, from Delherm. shows the current curve and the wave of muscular contractions obtained with this appa- ratus. Figure 313 shows the current curve with isolated induction shocks from a faradic coil and the waves of muscular contractions produced by them. Figure 314 shows the current wave from the usual faradic cur- rent and the tetanic muscular contraction produced by it. Lcdnc current* are currents which are uniform and unidirectional, but which are made and broken with a rapid rhythm similar to that of the faradic current. They produce a contraction similar to that from faradic currents, and are open to the same objections as to abruptness of beginning and ending and as to a tetanic condition during the ap- plication, and as to the small amount of electricity which traverses 1 Bulletin oflick'l dc la Sneu'tr d'ElootrothiTapio, August, 1907. MEDICAL KLKCTKICITY AM) Ko.NTOKX HAYS the muscle. I. cduc currents or any other Hinilarly rapidly interrupted currents of more than l.~> ma. would produce intolerable convulsions. V I'itr. '>!'_'. Sinusoidal current with Fip. 31'5. Isolated induction shocks. rli\ t liinii- \ .'iri.'ii inn in -tn-nirth. Mus- Ali,ii]*t rnuscuhir contractions, i-ular cdiitractioti -iinil;ir to j)li\'sio- ;i i'_ r ic nut-. These current- liave a slight advantapo over faradic currents for elect ro- mechanotherapy in the fact that the periods of current and the strength V V Gaiffe's Large Apparatus for Electromechanotherapy. The appa- l - in. ''> 1 > ha ;i primary coil through which pa-\ Unidirectional Undulatory Currents of Low Potential. Bordier's ol)servat ions' lead him to the conclusion ,hat the.-e currents repre- sented by the curve in Fig. - ( .\7 are even better in their effect upon mu-cular atrophy than the rhythmic, gradually alternating currents Fit:. o!7. Unidirectional undulatory current. given by the apparatus i p. 4W}> employed by the author. The apparatus for producing these currents differs very little in appearance from the one alluded to. It consists of a rheostat with a sliding contact, which is moved back and forth from the xero-poinl by an electric motor. The ph >/xioloi/ir it't'ict* of tin application of tin *f ciirmttx to muscles arc/ inntnr nerres are quite different from those of ordinary galvanic current-; made and broken by a key. or by the metronome int< rrnpter. The indit'fei'ent electrode should be a large plate, measuring n by ^ Indus, and covered with several hivers of damp doth and placed nude!- the patient's back. The active electrode usually connected with the negative pole is a sponge electrode, '_' I inches in diameter. Tiie speed nl the motor is varied so that it takes from one to two second- for the change from xero to a maximum current, and an equal lent:' h ' ' e for a rei urn to xero. The conl ract ion wludi occurs is of n _ lual character, like a physiologic contraction. The strength of the current required to product 1 mu-cular contraction in healthy mus- i- LTi'eatei 1 'han wit li sudden makes and breaks of t he galvanic current . : ' rophic muscles as much as In to ."in ma. may be required. These; heavy current- have been u-ed by Bordet.- who found that they cause a slight burnhm -en-ation which the patient can -land, instead of the severe burning feeling from the ordinary galvanic application-. The more at mphic the m u -de i-. the -t roniz'er the current required. As to t he -peed nl ' . ilations in the current, the more natiiial the mu-de, the more rapid -peed i- re(juired to produce contraction. The muscle 1 :''- -' m it- entire ma--, and the contraction i- limited to de. I i< >rdet produced a n inerea>e of si/e and strength ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 491 in the biceps of healthy men by applying these currents to that muscle. Tiie strength of current was 10 ma.; 100 waves of current were applied every day for fifty or sixty days, with an increase of '2 or 3 cm. (0.x inch or l.'J inches) in circumference. This was a slightly greater in- crease than was produced on the other arms of the same subjects by a rhythmic undulatory galvanic current with a change of polarity. These currents are valuable in the treatment of muscular atrophy. Leduc Currents. Lch. it is arrested before con- tact with the stationary brush has ceased. Different positions of the movable brush give periods of current flow which are equal to, or are only \. !,. ['. _,',,-. or ,-,',- the duration of the periods of current arrest. 1 Arch. d'elect. med.. September \~i. I'.Mo. 402 MKDH AI. KL1XTKH ITY AND ROXTGEN RAYS The number nt' periods per minute is varied l>y a rheostat controlling the motor which turns the wheel of the interrupter. The -tivnmh of current flowing during the periods of contact is regulated by the ordinary means. In the case of a galvanic battery, one can use a cell selector, reii'iihiting the nuniher of cells in series or in FL-. Ml'.i. Character of I parallel u!' a rheostat regulating the outside resistance. A rheostat will vvnerally be required with a storage-battery. Koth a rheostat and a volt-controller or shunt are generally required when the lid-volt direct elect lie-light current is used. The strength of current ordinarily required is less than with the ic current u-ually from -/,,- to M ma. The maximum strength of "i 1 1 to sd or more ma. sometimes used with the galvanic current is never to be used with the Leduc current-. The effect of the latter is that i)l a series of abrupt makes and breaks, and this would be exceed- ingly disagreeable, and perhaps dangerous, with strong currents. '1 he current si re n^t h may be measured by an aperiodic galvanometer. Thi- will indicate fairlv well the average or effective strength of the current, and from thi- and the relation between the period- of flow and :::-; one may. if de-ired. calculate the ab-olute -trength of the cur- rent when act u.ally fli iwinu'. The difference iii potential at the two electrode- where they are ap- plied to the patient, and al.-o the re-i-tance of the patient's body, may be determined by making a very brief ol i-ervat ion with a voltmeter , ' , ' wit h the 1 \v< i elect r< u le-. /' nttnuli ihi'* I nh rrn/tfi r.- Frimaudeau 1 lias devised a simple luciny currenis of the I.ediic type. An ordinary faradic coil with < -oft iron eore has it- own vibrating interrupter at one end. At ':.' otln i nd the alternate magnet i/at ion and demagnetisation of upon a vibrating hammer which make- and breaks a ' thai ha- no connection with either the primary or the I he farai lie c ( nl. ' '' ' (, 'it'ii ( ' urn nix. I'.ach successive period gives the same -t i . ; of current flowing for the -ame length of t i me and in the It ' : I ;.',,,. Li 'I'll- iiml l-'nmilic Curri nh Flu-. iil'J and iVJO). ; ' -. on i he ot her hand, -how periods ol current in alt er- ' -t renytli and duration of the successive impulses, I ' M",iir,Mle. M;,V, I '. M s. ; , | ,-t ,':, et in A 1 1 ,- . ;\ N. LMO. ELECTRICITY IX DISEASES OF THE NERVOUS SYSTEM 493 and even their periodicity, vary in consequence of imperfect action of the vibrating interrupter. The latter may not make perfect contacts every time. Advantages and Disadvantages of Leduc Current* a.s Compared with Farad ic Current*. The advantages are chiefly due to the fact that, the successive currents are of the same known strength and occur at a known rate per minute. The muscular response, a tetanic contraction lasting as long as the interrupted current is turned on, is similar to that pro- duced by faradic currents, but electrodiagnosis is much more exact with the Leduc currents. It is also easier to make accurate comparisons between reported cases and the one under observation. The disadvantage is that the successive currents arc all in the same direction, and the same polarization occurs which has such a tendency to vitiate measurements and cause irritation when the galvanic current is used. The faradic current is alternating, and is not open to this objection. This objection to the Leduc current may be overcome by the occasional use of the pole-changer, without which no electric apparatus can be considered complete, or by the use of an apparatus giving alter- nating Leduc currents, or, best of all, by transmitting the Leduc currents through the author's rhythmic rheostat and pole-changer. The Leduc apparatus may, therefore, be considered a most valuable improvement over the faradic coil for diagnostic purposes. Its ad- vantages for treatment are not so well established, although Leduc's "electric sleep" is thought to be a condition produced by the interrupted unidirectional current which the alternating discharge from a faradic coil will not produce. There is no doubt at all that the utmost regularity in the successive currents is desirable in every case, but unidirectional currents may not always be preferable to alternating ones. The fact that the induced currents from a faradic coil have a higher voltage than that of the direct primary current in the same coil does not enter into the problem. The Leduc apparatus allows of the application of cur- rents of equally high tension. Both the Leduc and the faradic currents are, however, known as low-tension currents. High tension is a term that applies more properly to the discharge from a static machine, an Oudin resonator, or a Ruhmkorff coil. It means a sparking distance measured in inches, not in thousandths of an inch, as in the Leduc and the faradic currents. Leduc has found that the most effective stimulation of muscular contraction is obtained when the duration of the passage of the current ' s TIMIIT second each time. Adjusting the apparatus for this length of current waves and for a frequency of 100 periods a second, it is simply necessary to determine the voltage necessary to excite muscular contraction: or, what is sometimes more convenient, the milliamperage required with electrodes of a certain area of contact. The contractions ordinarily elicited by electricity are due to the dosing and opening of the circuit, and not to a uniform flow or absence of current. They seem to be due to the variable period of the current; a very short . but still a measurable length of time during which the cur- rent is increasing from zero to its maximum strength or diminishing to zero. The variable period of the current at the closure of a galvanic circuit has been found by Blaserna to be 0.0004s second, and at the opening of the circuit it is 0.00027 second. 494 MKD1CAL KLECTRICITY AM) K(").\TtiK.\ KAYS These facts seem to throw some doubt upon the value of the chief feature of the Leduc currents /. c., the ability to regulate the exact duration of the successive periods of current flow, but this is hardly a correct view of the case. Though the period during which the current flows uniformly is a period without practical physiologic effect, its duration directly controls the length of time between the physiologic effect due to the closure and that due to the opening of the circuit, and we know what a very great influence rapidity of succession in electric impulses exerts upon physiologic effect. KKUINNINC, or MUSCULAR RKACTIOX WITH I.EDUC CURRENTS PERIOD. VOLTS. TIME oy PASSM.K OF Crit- KENT IN SKCOVI>S. -) '2 0. 00001 15 0.0001 15 0.0002 12 0.0003 11.5 0.0004 10.5 0.00(1.") 9.5 O.OOOti 9 0.0007 8.5 0.0009 7 0.001 EjTi c( of Lednc Currents upon Animal Development and Nutrition. In experiments by Bordier and Honnenfant 1 the negative electrode was placed at the nucha and the positive electrode over the sacrum; the skin was shaved. Rabbits about three iccckx old were treated every other day. The interruptions were .'-J7120 a minute. The first rabbit experimented upon had convulsions and fell over on its side with a current of IS ma. The current was then reduced to S ma., and allowed to flow for ten minutes. At the second such treatment the rabbit died, probably from com- pression of the trachea by an elastic band u.-.ed to hold the electrode in place. Other rabbits showed complete anesthesia and a somewhat accelerated respiration with a current of IS ma., and this was followed by "N ma. for ten minutes. The animal showed no bad effects. Sub- -eijuent applications to this rabbit were 1"> ma. at the start, followed by x ma. for ten minutes. Only twice during the two months' course of treatment did the rabbit show anv bail effects. On these occasions than the control rabbit which was not treated, it weighed 100 less than the other at the end of two months. It had grown, but la>t as if it had not been treated by electricity. During a week's ission m the treatment it mv\v faster than the other rabbit. ibbitn weighing over '> kilograms were treated in the same ' irrent was interru])t<'(l J.'l'JO times a minute, and was run ia. at first to produce anesthesia, and was kept at 10 ma. I hese t real mei it s were triven every da v for 1 wont y-f our that there was a reduction of 10 per cent, in the in t he radiat ion of heat from }'>(}() period KLKCTRICITY IN DISEASES OF THE NERVOUS SYSTEM 405 of the interrupter, and ouch ton minutes' treatment at 8 ma. equaled .'3 r 2 7 coulombs; and at 10 ma. equaled 4 coulombs. These results may find a practical application in the treatment of obesity. They certainly show that a lon.tr course of treatment by these rapidly interrupted galvanic currents should not generally be applied in the ease of growing children. This applies more particularly to treatment applied in such a way that the spinal cord acts as the principal conducting path. PRACTICAL EXAMPLES OF THE USE OF CONDENSERS IN ELECTRO- THERAPEUTICS IN CONNECTION WITH THE STATIC ELECTRIC MACHINE To Apply the Static Induced Current (Fig. 321). The inner armatures of two Leyden jars are connected with the two poles of the static machine, while electrodes connected with the outer armatures are applied to the patient. Kaeh time the inner armatures are charged, a current is induced through the patient in one direction. And when the inner armatures are discharged by the passage of a spark between the two discharging rods of the static machine, a current passes through the patient in a direction opposite to that of the charging current. The inner armature of the jar connected with the positive pole of the static machine becomes charged with positive electricity, and by induction repels positive electricity from the outer armature of the same Leyden jar through the patient to the outer armature of the other jar. Nega- tive electricity is repelled from the outer armature of the jar connected Fig. 321. Static induced current, regulated by slowly separating A and B. with the negative pole of the static machine through the patient to the other jar. On the discharge of the Leyden jars the charges on the external armatures are released and pass in the opposite direction. It is convenient to speak of the direction in which the positive charge passes as the direction of the current, and this is from the jar connected with the positive pole while the Leyden jars are becoming charged, and in the opposite direction while they are being discharged by the passage of a spark. The rapidity of the alternations is not very great it is merely that of sparks, and they may be readily counted. The quantity of electricity transmitted through the body depends principally upon the si/.e of the Leyden jars, while its tension depends principally upon the length of the spark-gap and. of course, is limited by the power of the static machine. An isolated condenser spark may be applied from a small Leyden 401) MKDICAL KI.KCTHICITY AM) ROXTeiKX KAYS jar already chargvel. The patient is not insulated, and the external armature of the Leyden jar is connected with the ground, while the other pole, the brass knob connected with the inner armature of the Leyden jar. is brought near the patient (.Fig. 322). A spark passes to the patient, and produces physiologic effects which are of diagnostic and therapeutic value, and especially so from the fact that the spark can be applied exactly to the desired spot, and can be perfectly regulated as to volume and consequently as to voltage. The author's technic is to have the patient seated or standing or lying about .'! feet from the static machine, but not upon an insulated platform. The operator holds a Leyden jar. his fingers grasping the outer metal coating. A wire or chain which need not be insulated is fastened to the outer coaling, and at its other extremity to a water or gas-pipe, which effectually grounds it. The static machine is to be in operation, and its discharging rods are to be fixed at a certain distance^ apart, and this regulates the voltage of the charge 1 . The latter cannot exceed the amount required to spark across the air-space 1 between the discharging rods. The Leyden jar is held so that the inner electrode, that is, the brass rod connected with the inner metal coating or armature 1 , touches one 1 of the discharging rods of the static machine 1 . It take's only a short lime 1 completely to toground I'lir. '-'>'2'2. Isolated Leyden jar spark applied to patient. charge the Leyden jar. and it remains charged until the iniuM' elee'trode i- applied to the patient. A spark is then produced, the patient and the 1 earth completing the connection between the internal and exteM'nal armatures. I mm the standpoint ot convenience in handling, as well a- wi'h regard to the physiologic effect, the appropriate si/,e of Leyde 1 !) jar i- one coti-i-t nm' ot a glass bottle 10 inches long and about '2\ inches in diameter, with external ami internal armatures covering the bottom, and extending ; j inches up on the side.- ol the jar. The operator ex- perience- 1,1, -en-ation either when charging the jar or when applying the spark to the patient. The capacity of the same Leyden jar is. of cour-e, Always the same, but the quantity of electricitv which it takes to charge 'In- capae-ity, as well as its tension, i- increased when the di-taiicc between the discharging roil- (if the -tatic machine is increased, distance -lioiiM be ', inch at the commencement of the examina- I. and mav be Lrradnally incre'ascd to I. or possibly ndimj upon the nature of the case 1 , the sensitiveness of the I-, -;:,!, to which the -park is applied, and the individuality of the patient. The -park may be applied through the clothes or directly to t de -km . I.-olat ed condenser disc ha rges mav be a ppiiei 1 in rapid suc- ces-ion, and every one he perfectly regulated. Almost anv tvpe of ELECTRICITY IN" DISEASES OF THE NERVOUS SYSTEM 497 static machine will charge a Leyden jar amply for this jmrpose. It does not require one of the large glass-encased machines with eight to sixteen or twenty glass j>lates used for the generation of the j'-ray. Condensers for stimulating muscles or nerves have a cajmcitv of ifiW' ion- or ' tl t tn(> most. i 1 ,) microfarad. The Leyden jar cannot he successfully charged for use in exactly this way, either from an induction-coil or a transformer. The alternat- ing character of the impulses prevents the armature which is applied to one j)ole of the coil from receiving a j>ermanent charge of either {positive or negative electricity. Leyden Jars or Other Condensers as an Essential Part of High- frequency Apparatus. A single example will suffice to illustrate this use of the condenser principle. Fig. 323 shows a form of resonator employed by the author. P and P' are the jioles of an x-ray coil or an x-n\y transformer, whose discharging rods or spintremeter are wide apart. A conducting cord passes from each j>ole of the coil to the in- i i- applied TO the skin or to a mucous membrane, the patient's body becomes the external armature of the condenser. The glass and ''"' "f the tube form the dielect ric and the metal rod the inner armature. Another cotiden-er electrode ' Fiir. :>2.~> consists of a metal rod with a hard-rubber covering. vacuum electrode- 'Fi inches between the glass in contact with the patient and the charged metal handle or leading-in wire. Klecirjc induction cannot take place to a sufficient extent in a condenser having a dielectric (> inches thick, and air at the ordinary H F y ' ^ 4- pi 1 ' -- . i! not acl as a conductor of electricity unless ioni/ed. And - not a -uflicienlly <^<><>t\ conductor for this purpose. The '' 1' con t a ins air or ot her iras at a pressure of } ti ' n n at mos- ' ' ' pei-~|er ( ||.H-]-,. ( . ,,| vacuum. \\ 1 1 1 c 1 1 |- all excellent conductor of n rent . ni tin rrnitli nwr ilirtrnili may be ihagrammatically hown a- in I :-. '.','27. At a certain in.-tani the metallic handle from the til- may have a positive charge. It induces. ' ' tiomt. a negative charge m the conductiim '1 air or .-aline -olution, contained in the tube, and 1 ''... |ue?ii : ivi- charge m the di-tal portion of the conducting ELECTRICITY IX DISEASES OK THE NERVOUS SYSTEM 501 medium. There again u condenser action occurs inducing a negative charge in the portion of the patient in contact with the glass. At the next instant the polarity is reversed at every point in the series. The Operation of the Condenser Electrode When (it Some Distance from the Patient. ig. 328 shows tliis in a diagrammatic way. At the instant that the distal portion of the conducting medium is charged with positive electricity, a condenser action takes place, producing through the glass and open-ail 1 dielectric a strong negative charge in the nearest portion of the patient. If the air-space is only a fraction of an inch, this nega- tive charge will break through the layer of air as an effluve or as a shower of sparks, as the case may he. In the diagram a negative charge is shown to have accumulated in this way upon the surface of the glass, held there just as in the "dissected Leyden jar." THE USE OF CONDENSERS IN CONNECTION WITH INDUCTION-COILS This is of the greatest importance, and has been considered on p. 148. NEURALGIA AND NEURITIS Satisfactory distinctions between the neuralgias and rieuritidcs are not easy to draw. The severe neuralgias pass over into mild or severe neuritides, whereas, the mild neuritides may be considered as neuralgias. It is largely a question of degree. So far as the seven 1 neuritides are concerned, however, certain grave 1 alterations are found in the nerve- trunks which are not known to exist in neuralgias. Such are cell in- filtrations in and about the nerve-fibers, proliferation of new connective tissue causing pressure, and various degenerations which are usually peripheral, but which also may be interpreted as central in origin. The chief neuralgias which are amenable to electric treatment and which the electric therapeutist is oftenest called upon to treat are those of tin 1 trigominal, brachial. the musculocutaneous, and the sciatic nerves. There are other neuralgias, such as ovarian, coccygeal, the neuralgias of herpes, etc.. which occasionally call for electric treatment, but in general those of the facial region, brachial, and of the sciatic distribution are the most obstinate. In the consideration of the treatment of the neuralgias one should bear in mind always the question of referred pains. These referred pains have been so exhaustively studied by Head, Dana, McKen/ie, and others that we are now in a position to refer the vast majority of the so-called neuralgias to certain disturbances in the viscera. These visceral dis- turbances, as i- well known, send or cause nerve impulses to travel to the spinal cord, which, coming in some sort of contact with certain sensory nerves in the spinal segment, are referred to the skin area of these seg- mental nerves. These skin areas have been verv accurately mapped out by the researches of the authors mentioned, and it is well known, through these researches, that the whole surface of the body may be divided into areas which correspond to or represent the cutaneous surface in con t act with the nerves of the visceral organs. This leads to the develop- ment of cutaneous tenderness in practically all referred pains, and this is a very essent ial factor in the diagnosis of this type of so-called neuralgias. These cutaneous tendernesses have a marked feature in contrast with the pains, which are perceptible over the area of a nerve-trunk, -uch as are frequently seen in the neuritides. 502 MKDICAL KLKt THICITY AND ROXTGKN RAYS Thus in the invest igat ion of the neuralgias special care must bo taken, first, to outline the importance of visceral diseases; secondly, to determine if such neuralgias may he due to growths on or pressing upon the nerve-trunks; and. tinally. to consider the specific type of herpes neuralgias which are due to the involvement in the posterior ganglion. It should he borne in mind that such involvement in the posterior gan- glion may set up very severe neuralgias without a corresponding herpctic eruption, although, as a rule, a skin eruption is apt to follow the inflam- mation of the posterior root ganglion. These herpetic ureas are clearly outlined in works on neuralgia, and the relation of visceral disease to herpetic inflammation is one of the most interesting chapters connected with sensory localization. The electric treatment, therefore, of the different neuralgias must take into consideration the manifold origin of these affections. The treatment of neuralgias due to visceral diser^es in other words, the referred pain neuralgias consists essentially in the use of electricity as a eounterirritant, the counterirritant being applied, if possible, in the area corresponding to the viscus affected. Medical treatment of the viscus should not be overlooked, being often of more value than the electric treatment of its reflection only, so to speak. Referred pains in the head, neck, and face are frequently the result of disease of the nose, the eye. the ear. the tongue, the teeth, the tonsils, the larynx, or of the brain itself. Finally, a number of the internal viscera, such as those of the thorax and abdomen, which receive their nerve-supply from the vagus or the glossopharyngeal nerves, are capable of inducing referred pains in and about the head and neck, and some very persistent neuralgias of the face are often due to disease.' of viscera below the diaphragm. Kvery case of neuralgia or neuritis calls for an .r-ray examination of the teeth. The cause is often dental infection. \Y. II. Schmidt 1 gives this treatment for neuritis: Diaynosi*: In neuralgia and myalgia the electric reaction is always normal. Neuritis produces altered reaction varying from a sluggish response or hypo- excitability to complete reaction of degeneration and loss of tendon reflex. 1'or ti'intnn >/t, countcrirritntion is produced by a vacuum elec- trode from one pole of an induction coil or the static brush discharge or the high-frequency eflluve. Ultraviolet rays may be used for a deep effect, lasting two or more days. II cat is applied from a 500 watt lamp for a half-hour or by diathermy. Acntr nruritix: Absolute rest, mild positive galvanization or diathermy. Siihncutr m'urifi* is benefited by >00 wat t lamp one-halt' hour or more, posit ive galvanizal ion one-quarter hour, high-frequency vacuum electrode mildly along the course of the nerve; th.' static brush discharge over the most painful area until defi- nite redness occurs; or high-frequency efiluve. the high tension faradic current, diathermy one-half hour, counterirritation by ultraviolet rays, or the static wave current beginning with a short gap of 1 inch or less and tor a -hurt duration. Chronic neuritis n\n\ be t reat ed bv the heavy static wave current, electric light baths, and muscular contractions. .- i- treated by 500 watt incandescent lamp, rhythmic muscular contraction-; produced by any electrical means. AIIKT. .drir Kl-rtr. ,: h>Tany :ind Rii'lioloL'y. vol. \x\vi, No. ;}. March, 191S, ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 503 For neuritis Do Kraft 1 applies diathermy, light mild wave current, or mild resonator effluve by bipolar method. JVI. L. H. Arnold Snow 2 in the treatment of neuritis uses the static wave current lightly and only as a palliative. One or two connected electrodes are applied over the affected part for twenty minutes; spark- gap according to tolerance, but too strong will aggravate the disease. x-Rays are applied for chronic fibrous conditions, and spinal vibration to relieve muscular tension. Diathermy is applied longer and with slower heating than is usually advised. W. B. Snow 3 claims that the static wave current in neuritis does not irritate acute cases. De Kraft, 4 in diathermy for neuritis of the shoulder, applies one large electrode to forearm and hand and another terminal to the De Kraft chair as a dispersing electrode. This warms the whole shoulder, whereas if applied higher up the current would pass across the axilla; 300 ma. are gradually increased to 1500 ma. Then he uses the static current, metal plate over the shoulder and |-inch gap. Later, when tenderness has subsided, he applies the effluve from the static resonator. In neuritis, digital pressure and the static wave current (Hirsh) should reveal tender areas. A. B. Hirsh 5 for acute neuritis uses an incandescent lamp one and one-half or two hours. (Burdick lamp made in Milton, Wisconsin.) The wave current makes the disease w r orse according to his experience. For a neuritis of arm and shoulder Martin uses the static wave current over the brachial area with smallest spark-gap as a test. Static wave current followed by sparks over whole plexus and down arm are used for treatment. Electric Treatment of Neuritis. In cases of neuritis the nerve is usually to be treated by galvanic currents; the paralyzed muscles, by faradization or galvanofaradization. Sinusoidal currents may be applied in the same way as faradic or galvanofaradic currents, and often succeed in cases of neuritis where these currents have failed. Cases Simulating Neuritis. In a case of lancinating occipital pain palpation showed typical small fibrositis nodules. The treatment was by the static wave current, radiant light and heat, and vibration (Hirsh 6 ). Tremor of right upper extremity with neuralgic pain throughout left brachial plexus. Sites of true neuritis could not be located, but indefinite evidence of deltoid fibrositis with possible subacromial bursitis. Galvanic, + forehead, -- below occiput; radiant light and heat with the static wave current alternating with salicylic ionization over the shoulder for brachial plexus and over deltoid region, all were tried, to no effect, and later the lesion was found to be an intracranial tumor. Static Induced Sparks for Neuralgia.- These are applied by a metal electrode through the intermediary of a static regulator. Direct static sparks are also useful. 1 Amor. Jour. Electrotherapy and Radiology, vol. xxxvi, No. 3, March, 1918, p. 9. 2 Ibid., March, 1018, p. 96. ' Ibid., March, 1918, p. 97. 4 Ibid., March, 1918, p. 08. 6 Ibid., March. 1918, p. 98. 6 Ibid., No. 1, January, 1918, p. 1. .">04 MEDICAL KLKCTR1CITY AND KONTCIKN KAYS Trigeminal Neuralgia. The most persistent of all the neural- L r ia- of the face is that known so widely as tic douloureux. This belongs to the group of neuralgias due to disease of the sensory gan- glion. It differs, somewhat, although not always, from The ordinary herpes neuralgias in that it is more persistent, more severe, is usually not a--ociated with paralvsis. and does not cause an herpetic eruption. This is not an absolute rule, but is the general course of the disease. Any one of the chief branches of the fifth nerve may be involved, and in the more protracted case- it is usual to find that all the distribution of the fifth nerve is implicated, and in the chronic cases certain trophic changes usuallv accompany the onward progress of the disease. Ordinary faradie or galvanic electricity, more particularly faradic, is practically of no value in the treatment of trigeminal neuralgia, save perhaps in the very early stages. The principle of a counterirritant does not apply to these cases, as it does to the treatment of referred pains. Certain modifications of electric treatment, however, have proved of service in this persistent form of neuralgia. Thus high- frequency currents and high-voltage currents have shown themselves to be of value, and the treatments advised by Bergonie and Leduc have been reported as efficacious. Leduc 1 has reported an interesting case in which he has been able to apply, by the method of cataphoresis, the ions of quinin with permanent relief. The case was that of a woman sixty-eight years of age, who developed a tic douloureux after refrigera- tion. The inferior branch alone was involved. The area was ex- quisitely tender, and the slightest variation in temperature caused a paroxysm. She was unable to swallow anything cold, and even the blowing of cool air upon her face was unbearable. She was unable to >leep. her teeth were sacrificed to no advantage, and the submaxillary nerve was divided and the lower jaw resected wit hout results. Hichlorid of quinin in 1 per cent, solution was applied electrically for half an hour, with a current which was gradually raised to 20 ma. This gave rise to redne-.- in the skin and edema, but there was a marked diminution in the pain, and the patient was able to sleep. A second application was made three (lays later, since which time 'one month after the application) There had been no return of the pain. Leduc has never given The subsequent history of this case, and it is certain that to report such a case one month after does not prove the permanent efficacy of cataphoresis in t he ' n-at iii'-nt of 1 his affect ion. Uergonie has advi-ed a method of applying very heavy currents an.- i 'l electrodes which cover t he em ire side of t lie face. The cur- ' ' i- applied in as large doses as from (ill to s() ma., the active electrode elect rode covered with 'lamp wadding or clay) beini: the ' pole, and bein'.: very accurately fit ted to the surface and model- ;::- "i ':. : ici . The duration of the application should be at least half "/ fin' T r"!i in i mil \ i nrnl'/in. Correct Technic is nt when applying current - of t his st reiigth. in order to > or burns. The elect rode- niu.-t 1,,. large, and of ' I lie current uill be uniformlv distributed over all An ordinary -pon^e electrode often ha- one or more .' in : ' i- almo-t directly in contact with the -kin, and iiivi il- K]-rr rich ' Mci|ic :i lc. I'.Mi I. ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM consequently practically the entire current would puss to the skin at a small spot and produce a burn. The active positive electrode is made of sheet metal fitted to the shape of the side of the face, and \vith three prolongations extending over the forehead, the upper ja\v. and the lower juw. Felt, clay, or kaolin \vet with solution of sodium bicarbonate prevents any metallic contact with the skin. The indifferent, negative electrode is of the same nature, and is applied at the nape of the neck or between the shoulder-blades. A rheostat should be tised to turn the current on and off extremely gradually. A continuous current of as much as (10 ma. will sometimes succeed in greatly relieving a case of trigeminal neuralgia after extraction of teeth, nerve resection, and removal of the (lasserian ganglion have failed and the improvement may be permanent. The Method of Mild Galvanization. Three to twelve milliamperes may be applied for an hour at a time from similar electrodes. Distribution of the Current in Applications to the Fare. The heavy galvanic currents which are sometimes applied for facial neuralgia, either for the effect of the currents themselves or that of the medicinal ions carried by the current, do not pass in a straight line from the active electrode to the nape of the neck, where the indifferent electrode is placed. The current is diffused through every part of the head and neck, but is of greatest density along paths of least resistance. It passes with a practically uniform density through all parts of the skin in contact with the electrode, and also through muscles and fascia. \Yhen it comes to bone, it encounters resistance which is very much greater than at the different foramina and the vessels and nerves passing through them. The greater part of the current, therefore, follows these important struc- tures and passes through the (lasserian and other ganglia and the brain, cerebellum, and medulla. The symptoms observed by (lautrelet (p. 401) from the application of similar currents in rabbits are due to a primary stimulation and an ultimate paralysis of the nervous system along these conducting paths. The method of heavy currents for long applications is to be applied with great caution, and only by an expert physician. The following physiologic effects are introduced at this point to enforce this admoni- tion. Although the electric treatment of trigeminal neuralgia is of great service, particularly in the milder cases, il cannot be said that at the present time any sure electric method is known for the very severe cases, and one must sometimes have recourse to surgical procedure.- which have been advised. Alcohol injections into the substance of the ( lassenan ganglion or the affected branch of the nerve have proved to be the simplest and most efficacious method of treating these affec- tions. Such injections are easy of application, are not attended by any disastrous by-effects, and the experience of Schlosser, Lew. and others shows that relief may be sriven for yeats at least, even if such injections do not make a permanent cure. 1 /'< // j'-li'ii'/ n/i/l hi/ II tt/Ji-t'i'i '/'/' /"''/ ('uri'( itt*. These important and often successful methods are described on pp. f)!l3 and 1 1. Radium. This has also been used, but without lasting success, in the cases which the author has seen. 506 MEDICAL ELECTRICITY AND KOXTGEN RAYS Static Electricity for Tic-doukmreux. Win. B. Snow 1 applies the static wave from a metal electrode held in place with the bare hand and -i inch spark -gap. He expects a cure in a week, and uses the same appli- cation for neuritis in general. Cervicobrachial Neuralgia. Neuralgia in one or more of the brandies of the bracliial plexus is not infrequent. The pain is usually felt in the neck, and shoots down the nerve-trunks to the arm and fore- arm. Movements of the arm are usually very painful, and the hunched-up shoulder and half-carried arm are characteristic of the attitude of these patients. The most frequent causes of brachial neuralgias are exposure to cold or injury, tumors, and poisoning from gout, alcohol, lead, or syphilis. Brachial neuritis may be an expression of a greater degree of injury in the nerves at their origin in the plexus, or somewhere in their course. Here the pain is apt to be more severe, th" nerve-trunks themselves become tender, and trophic changes take place in the muscles, the skin, and the nails. The deltoid muscle, for reasons as yet little appreciated, is apt to develop a deltoid neuralgia or neuritis. It is. as a rule, a mild inflam- mation of the circumflex nerve. It is a not infrequently annoying trouble among people who write considerably, and may perhaps be classed at tini"s as an occupation neurosis. It is a not infrequent dis- order among workers with the broom, and is seen here in some of its more severe forms. In the diagnosis of the site involved in cervicobrachial neuralgia and neuritis certain additional symptoms are of value. In inflammations low down in the cervical area, involving the first dorsal, pain over the clavicle is very marked. Furthermore, a neuritis in this region is apt to involve the sympathetic fibers, which have a relation here with the upper dorsal .-elements of the cord. The evidences of these sympathetic signs are a slight retraction of the eyeball; the lids come closer together on the affected side, t he outer angle droops, and there is a slight contraction of the pupil on the affected side, with diminished light contractility. Some cases .-how a dilated pupil on the affected side. Many of the severe cases of bracliial neuritis are extremely obstinate, per-i-tin^ at times for months rather than weeks, and they tax the therapeutic resources of the attending physician. In addition to ordinary method- of treatment by rest, salicylates, iron. heat, and general supporting measures, counterirritation by means of the actual cautery and 1 he use of electricity are the two most sat i.-fact' iry measures to employ. }'.}!'> }']( current - are harmful in t lie very early si ages of the affection, and practicallv the onlv form- that are ot service are the direct, high- frequency, and -iiiu.-oidal currents. Induction current- are usually harmful. I.\'i<']-e. at least so long as pain is present, is verv prejudi- H; ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM .)()< trunks for at least ten minutes. The pole should be shifted from time to time, but not removed from contact with the arm. The sinusoidal arm bath is of value when the pain has receded to such a degree that the pain is felt only on movement. High-fre- quency currents are often beneficial in the treatment of the chronic painful stagers of the disease. They relieve pain greatly, even when they exert no marked effect upon the course of the neuritis. Intercostal Neuralgia. Bergonie's method of covering the painful area with a large positive electrode and applying currents of 50 to SO ma. for half an hour at a time is effective here. The same careful technic is essential as in cases of trigeminal neuralgia. The x-ray is very effective in these cases. Glass vacuum electrodes from the Oudin monopolar resonator also succeed very well. A local electric-light bath is excellent, producing its effect chiefly by dry heat, and if the skin is slightly blistered, this does not cause pain. Sciatica. This is perhaps the most frequent of all the neuralgias of the body. Lying, as it does, in an exposed position, the sciatic nerve is subjected to frequent stretching, and not infrequent chilling and trauma. It is a medley, in reality, of conditions rather than one, and what has been written with reference to the occurrence of referred pains must be borne in mind in all cases in which pain in the sciatic nerve distribution is found. As a referred pain, sciatic neuralgia is frequently found as a result of affections of the prostate 1 gland, of hemorrhoids, of fissure of the anus, and in a few visceral conditions in women associated with retrodisplaee- ments and procidentia. These are not cases of true sciatic involve- ment, although the severity of the pains may lead to such a diagnosis. In much the same way chronic hip-joint affections may give rise to sciatic pains. Pressure on the nerve from chronic constipation, from a pregnant uterus, and from tumors is to be borne in mind. Chronic progressively increasing pain in the sciatic distribution points to a tumor pressing upon the nerve-trunk within the pelvis. Finally, one has to bear in mind that specific hcrpetic eruptions occurring in sciatica point to inflammation in the sensory ganglion. These cases are frequently severe, but are apt to recover with a fair degree of rapidity. The symptoms will vary much. The referred pain sciaticas are not of very wide distribution as a rule; those due to herpes may involve most of the branches. The true perineuritic sciaticas vary considerably, sometimes involving only a few branches, at other times occupying most of the entire distribution. The agonizing and paroxysmal nature of the pain is one of its chief characteristics. It is usually increased by move- ment of any kind, and more particularly so by all those movements which call for hyperextension of the nerve. Tenderness along the nerve-trunk is usually present. It is apt to be absent in the referred pain sciaticas. As a rule, the pains are worse at night, and eventually the patient is forced to limp and hold the limb stiff, frequently giving rise to a distinct and typic posture, with a resulting deformity. So far as electric treatment of sciatica is involved, it should be considered purely as an adjuvant, although high-frequency current applications and those of Leduc's low-tension interrupted current are MKDICAL ELECTRICITY AND ROXTGEX KAYS often of immeeliate- and peTinanent relief in a number of the most in- t ract able cases. In the referred pain sciaticas counterirritat ion by the faradic brush or the static bree/e is of signal service, but is useless in the severe pe-ri- neuritic cases. Heavy constant currents are valuable for their sedative effects. Laru'e electrodes should be used, and long applications are necessary o() to til) ma. for from ten to twenty minutes one electrode over the iliac fossa, the other to the sciatic nerve in some part of its course 1 . Both ascending and descending currents should be tried, since the deter- mination of the best direction of the current has been, and is still, the subject of considerable controversy. In both acute and long-standing cases high-frequency currents are of very great service 1 . They seem to have most value in cases in which thickened painful nerve-trunks are present. Just why. is not known. It is highly injurious to attempt to treat sciaticas e>f the perineuritic type too early. Absolute rest is the first requirement if one would avoid the chronic infiltration connective- tissue changes which inevitably lead to the more protracted chronic forms of the disease 1 . Kven the use of the constant current, which is the only admissible form, should not be begun prematurely. Various forms of the sinusoidal current are useful in the subacute stages. The bipolar bath with this type of current is most satisfac- tory. It should be used only when relief follows its application. If such usage provokes pain, it is wiser to delay its application. In the very obstinate- forms it may be assumed that adhesions have been formed. These may frequently be diminished by the use of high- frequency currents and ultraviolet ray emanations. The results in some of the author's cases (p. ~>M) have been magic. Scidtica, Snow 1 says, is often due not to neuritis but to a dilated stomach, consolidation at the apex of the lung, enlarged prostate, colonic or sigme>idal impaction. He caused the disappearance of sciatica in three high-frequency treatments of an enlarged prostate. Diagnosis: When radiant light and heat and wave current for three or four weeks i pat ient not allowed to exercise) fail to decidedly be-m-fit sciatica, look for something else. .r-Uay very use-till wlie-re- there 1 are tibroiis adhesions around the nerve, often due to sitting on hard sub- stances. Alternate with electric liirht. Mild treatment two or thre-e times a week 'John \\ . Torbett '-'}. The static wave current with metal plate may be used to locate t ender point s by pain pmduced at t he site- of t lie lesion. In 1 he arm, placing t he elect rode from t lie clavicle- backward r the scapular region, a very short spark-gap will cause severe pain some point; this i< the site ot the lesion. The same result ocean's the sciatic notch in .">() per cent, ot sciaticas. The electrode' is 4 IH-S ui.li- and 1'J indies long, and extends Ironi the sciatic notch up the lower third of the quadratic lumborum museaV; 1',-inch excruciating pain at the sciatic notch it the lesion is i.ain is elicited over both sciatic and anterior crural -ion is intrapelvic. \\ith an electrode over the ne>tch ar region, if there are lumbar metastasis or Pott's disease, treatments will aimravate the disease, r-b'av istheemlv \itii-r .l-iui 1 tpithrr.-ipy :iinl l!:nlinlMi:y. vol. \x\vi. N'n. 1 ; ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 509 means of absorbing local hyperplasia, but it takes months of small doses. The vibrator is of the greatest use in locating the parts of Ihe nerves requiring treatment. Then the static wave and sparks clear up the majority of cases. 1 Sciatica and neuralgia of front and outer side of thighs is benefited by static wave current with 5x8 inch metal electrode on upper abdo- men for debility and poor digestion (Hirsh). Win. Martin 2 says sciatic neuritis may be tested by the static wave current, placing the electrode first over the sciatic notch, and then along the course of the nerve and its branches. Treatment may be by the wave current to the most painful areas, followed by indirect sparks. Remnant of pain at fibular area, static induced very small electrode over the head of the fibula and a larger one over sciatic notch. Fairly large 1 spark-gap, one pole grounded. Sciatic neuritis. Wave current soon lost its effect of hurting and static induced substituted. First smallest Leyden jars, later quart size. Chronic Sciatic Neuralgia. Galvanic, Faradic, and Static Applica- tion*. Weak Galvanic Currents. Eight or ten milliamperes may be applied, as already described for heavy currents; or Benedikt's method of galvanization of the sacral plexus by a metallic electrode in the rectum and a large electrode over the sacral or lumbar regions; an electric lavage may be used instead of the metallic electrode for the rectal pole. Farad- ization may be applied by sponge electrodes, one over the lumbar region and the other over different painful spots and the affected muscles; or the active electrode may be a faradic brush, and, if so, the secondary coil should be of fine wire, to avoid muscular contractions. Static insulation followed by static sparks along the spine and the sciatic nerve, and static induced currents are all useful. Static Induced Currents for Sciatica. The patient is not insu- lated, and holds a large plate electrode connected with the external armature 1 of the positive Leyden jar upon the skin of the epigastric region. A small metallic ball electrode from the external armature of the other Leyden jar has an insulated handle by means of which it is applied to the skin in the lumbar region over the emergence of the sciatic nerve from the vertebral canal, and then to the different painful spots without breaking contact with the skin. The discharging rods of the static machine should be separated far enough to produce visible con- traction of the lumbar muscles at each spark. This separation will usually be less than half an inch. After ten minutes' use of the negative electrode the connections may be changed so as to make the positive electrode 1 the active 1 one 1 . A static bath with penvcrful sparks along the lower part of the spine 1 and the sciatic nerve may be 1 given at another treatment, alternating with the static induced current treatment. The best results .-ire 1 obtaineel frenn daily treatments, and De Blois 3 reports 80 cure's out of about 100 case's tivate'el. 1 Elizabeth \Vripht, Amor. Jour. Electrotherapy and Radiology, vol. xxxvi. No. 1 , January, 1D1S. p. 7. - AMHT. Jour. Klee'trothorapy and Radiolouy, vol. xxxvi, No. 9, September. 191S. p. 2t;:>. 3 La Presse medicale, April 10, UK)."). 510 MEDICAL ELECTRICITY AND KONTCEN KAYS Central Mca*ur< * for Sciur // Malic, induced Current. The large indifferent electrode, 10 by 14 inches, is moistened and applied to the back. Smaller ones are strapped to several different affected muscles and all connected. Connections are made with the outer coats of the two Leyden jars. Slow speed is turned, and a spark-gap that will yield marked but not painful contractions (HO per minute) for about ten minutes. Light, mechanical vibration, and massage are also used. Jones' summary represents the author's position so thoroughly that we cannot refrain from quoting it in this place: "In every case of infantile paralysis which is not clearing up satis- factorily it is important to apply electric treatment, continuing it for six months to a year or more. " It is the exception for a muscle to be so completely destroyed by poliomyelitis as to be without any fund ional fibers, and these remaining fibers can be cultivated by persevering st imulat ion of them. " \\ here the muscles show only the reaction of degeneration, or even where reactions are entirely abolished, some improvement may be hoped tor in a good percentage of cases. "The amount of restoration which may be possible in a muscle wil 1 depend upon the number of surviving ganglion-cells. \Yiih prolonged treatment recovery advances very much farther than one might expect, and is infinitely superior to the results obtained when treatment has not been given. "!] ven where the electric reactions are not altered in quality, it is not U'ood practice to leave the case to lake care of itself." F. K. Peckham- t reats anterior poliomyelitis a* follows: Wave current over lumbar and lower dorsal regions for the legs; or upper dorsal and lower cervical if the arms are involved; 500 candle-power lamp, prefer- ably wit h blue glass screen, over back, abdomen, and paralyzed members twenty or thirty minutes. Later add sinusoidal current to stimulate muscles and restore tone, also vibration applied to the legs. \Y. 1). Snow :: for poliomyelitis uses radiant light and heat, static. high-frequency, and sinusoidal currents. For these cases the sinusoidal with one electrode over the spinal center and others to affected parts is better than to two ends of a muscle. The static wave current has been regarded by Snow as very val- uable in loco/notor afnxia, spastic paraplegia, traumatic injuries of the -pine, transverse myelitis, pachvineningit is. For (iiriitiic ('/:.-<(. -< i>f poliomyelitis he applies a static wave current \vithaspark-gap 1 foot lone and a sinusoidal current of such a strength as will cause gentle contractions on the sound side, also high-frequency currents. 1. SHOW. Jour. Advance,! Therm.. October. I'.U'J. 5. March. I'.Uv 514 MEDICAL ELECTRICITY AND UOXTGEN RAYS Cfirnnir r<>lioini/' a rn 'he availability ot elect rich v for the t reat men 1 of disorders ot tlii _ ip : far from beinu conclusive. Much depends upon the attitude '.f the observer. It i- admit ted t hat t he cure of t rue posterior l.eoj advance,] at all b\ any vet d. vi-i d form of eloc- '-'/. I'am- ma\ be relieved, minor palsies helped, cle- improved, and the function- of the bladder I i. but t rue tabi - dor.-ali- ha- not yet suc- cumb' ' ' .< ' be seen uhv 1 i- -,li\ !il.' liln >od of it- dointr ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 515 so. Pseudotabes of neuritic nature following poisoning by alcohol, lead, aspergillus, ergot and its allies, or other agents causing a mild ascending degeneration may recover after the application of the electric treatment, but it is not even certain in these cases that the neuritic process has been hastened in its repair by the electricity. These pseudotabes cases re- cover after treatment by almost anything, or nothing, and hence it is of little profit, to argue the question without a nrixon d'etre. Application of Gnlvanic Current* to the Spine in Loconwtor Atuxiri !>!/ M <'() ma. is gradually allowed to flow for about ten minutes. The treatments are given three times a week for four to six weeks. All the current passes through the patient 's body, and according to the rule by which currents travel chiefly by the best conducting path, we know that a large proportion of it traverses the spinal cord. Allan! and Cauvy, 1 who suggested the above technic, believe that a favorable effect may be exerted upon the hyperemia and the sclerosis, and especially the lightning pains and the transitory paralysis of the early stages of the disease may be benefited. Vexic/il Crixcs in Locomotor Ataxifi. Treatment hi/ Gali'rnric Cur- rent*. The bladder is filled with boric acid solution, and a negative urethral electrode is introduced into the bladder. A large positive electrode is applied over the lumbar region, and a current of 40 ma. is gradually turned on and allowed to flow for fifteen minutes. Treatments are given twice a week. Can it be claimed that electric treatment will delay the progress of a tabes case? In view of the great chronicity of the affection and its irregular course, particularly its long periods of non-progres- sion, it is hazardous even to claim this for electric treatment in this disease 1 . The last word, however, has not yet been spoken, and it will be pre- mature to negative on a priori grounds some new claimant to thera- peutic honors. It is certain that the radium treatment, .r-ray treat- ment. Finsen-light treatment have thus far disappointed their advo- cates. The requisites for proving the claims are extremely severe, in view of the many-sided character of this affection. The x-Raij and High-frequency Current* A]>j>!i(d to the Spine in Lorotnotor Ataxiu. The author has seen great lasting improvement, though not a cure, in a case which was also treated by mercurial injecl ions. Diffuse Spinal Disease (.\fi/eliti* Types). In those patients in whom the paraplegia is spastic \ve cannot look for much relief from electric treatment, but in the ataxic types associated with lost knee- jerks, in which involvement of the gray matter seems evident, the indi- cations for electric therapy are somewhat similar to that already con- sidered in the Progressive Muscular Atrophies. Certain of the ataxic paraplegias are much benefited by the judicious and persistent use of both galvanic and faradic currents. Intraspinal Disorders (Ryringomyclin Tu/n ). It is a curious fact fllti MKIMCAL KI.r.CTKICITV AND HiiNTiiKN KAV> that of all the disorders of tli" spinal cord \vhicli would sccin to offer thf least hope for hfiit-tit from electric t n-at nient . syriiiii'omyelia should be one in uhidi -udi treatment has been followed by definite and unmis- takable -iii'Ms of bet ternietit . llaviiiond has reported the iM>od effects of .r-ray t feat men t in a number of cases. The pain- have been stopped, the pro^fe. of the atrophies delayed, and other sif these are the infantile cerebral palsies and the adult hemipleii' not 'n deal in futures, it i- sufficient to make the general con- f'- ion of faith that our pre-ent standpoint i- that electricity mav be an e\tre!iid\- iin j iort ant adjunct to our therapeutic resources, if not the ent in -uiirci of r> liance. Hemiplegia. In the organic hemiple^'ias n should be borne in mind thai ':. :,'-' motor neuron i- involved. We cannot expect bv electric 01 nil 111 : - to obtain the regeneration of the libel's in the affected corti'i path. The injury done liere is more or less inevitable and '.:.':.' I' he spinal peripheral motor pat h. however, is unaffected, place in the musde.-, bones, and blood-ves- - 1 . - oi ; 'n. pa raly/ed hinb are t he result not oi an v real inherent affect ion : i in n-. but of the lad; of phy-iolo^ic functioning in t h> ; iai i of the pa! h. 1' i-. ':. ' ion , evident that persistent regard paid to the unmodified ..'' I- ab-olutel\- essential, and one linds in the use !'\ help! Ill t herapelll lc resolil'ci . (lid hellli] )l(''ic ;' treatment or treatment bv mas-au'e bee,, me more bui b\ means ol ml muscular n'/mnast ics. Lial'.'anic and farad ic current.-, a ureal amount of improve- KLKCTKH'ITY IN DISEASES OF THE NEKVOVS SYSTEM 517 merit may be brought about. This improvement, however, will not pass beyond a certain point, and just how far such treatment may In- effectual depends upon the individual case: general laws cannot be pos- tulated. For the prevention of the development of rigidity the use of both the faradic and galvanic currents is beneficial. After rigidity has set in and has been present for a number of years the results are less valuablt in fact . massage is t hen more serviceable. Ti'intnmii of Ilcn/i />l<'y the alternating current of low in- tensity and slow interrupt ions, and should not be of more than five minute.-' duration at one time, while care should be taken in ascertain- ing the re.-istance of the brain tissues to the interrupted current. This subject will be discussed more fully in a separate paragraph, under the capt ion of Fleet ric Sleep. Infantile Cerebral Palsy. The indi\idual lesion which may be present m this type of affection varies so widely that we cannot in this place attempt to outline the symptomatology of the group. Suffice it to say that the chief damage is done to the cort icospinal neuron, and may manifest itself in monoplegia. hemiplegia, or diplegia. In the monoplegic types nature herself does much to minimize the damage done, and great improvement in the functional capacity of the affected muscles may be looked fur Jrom her unaided efforts. Both massage and electricity should be utili/ed early in the treatment of these para- ly/ed children. The indications are precisely the same as those which have been already spoken of in t he paragraph on lit miplegia. It is to be borne in mind that the lesions in infantile cerebral palsy, when not due to a generalized encephalitis, are of the hemorrhagic type. MKDICAL KLKCTHK ITY AND RoXTCF.X RAYS anil that functional losses arc- much more extensive than the primary anatomic defect. It should, therefore, he the aim of the electric thera- peutist to minimi/e. so far as possible, the teiulency to the continuance of this functional defect until the time when the exercising of the hemor- rhage area would of itself bring ahout an improvement in the condition as to movement. Both galvanic and faradic currents will prove of service, these currents beinir useful for the maintenance of nutrition. The use nf massage in conjunction with the electric current should not he lo.-t siu'ht of. the two mutually assisting. Some students have ob- tained a like stimulation of muscular tone, and nutrition hy the use of high-freiuiency currents, induction discharges, and static breezes. The latter, however, are more useful in maintaining skin nutrition than they arc' in affecting the muscular tissues beneath. New Growths in the Brain. Here the symptomatology is so varied that wo must refer the reader to works on neurology. What can be expected of electricity in the treatment of new growths? It must be confessed that it is not hy any means clear that the electric treatment of new growths is of much service, and this is not the place to consider what radium emanations or ultraviolet rays may do for certain forms of intracranial growth. In view of certain recent results obtained in the treatment of syringoniyelia by the use of .r-ray and by ultraviolet liidit . it cannot . on a /irinri grounds, be stated that similar types of tissue degeneration in the brain may not be beneficially treated with this form of electrically produced energy. Manifestly surgical procedures are those best adapted for the treat- ment of intracranial growths, but in view of the Bloomy outlook, even under the best of conditions, research in the matter of the treatment of growths by different types of electric energy should not falter. Epilepsy. It seems unnecessary to repeat that epilepsy is not the name of one diseasr there are several different epilepsies. That the motor discharge induces the familial' picture is true, but the causes of the motor di-charge vary from slight emotional excitement to actual anatomic destruction. It seems incredible that electric action could affect anatomically altered brain tissue to such a degree that the epilep- tic discharge could be modified, and such is the general experience of those who have t ried electric methods in the treatment of epilepsy, (lood ob.-ep.-i rs, -uch as Althaus and Krb. have, however, reported beneficial irn til being passed for one anui |e occii j >ving l he mi. (i placed over the occiput, and the same tvpe of ctir- ir ; he same lengt h of t ime. 'hni nl.- have been reported to have been of benefit in ' l.- conceivable that such treatment has had an effect i'o ;h which had been the primary cause of the irritation i I he motor discharge. ( >ne cannot . however, pin mea.-'Ures. They should be adopted as expedients yel in a position to maintain that they should be ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM GENERAL NERVOUS DISORDERS Of the more general nervous disorders, irregular forms of muscular spasm may be considered. So far as habit spasms and tics of various types, including the tic of torticollis or wryneck, are concerned, it seems certain that electricity is of very secondary value. In most of the habit spasms the psychic element is very strong, and electricity, instead of being of service, usually tends to aggravate the ills that are already there. Those forms of spasm or tremor or irregular tonic or clonic movements which are of an organic nature due to minute alterations in the vascular supply of the central nervous organs, also resist electric treatment. So far as the cases of wry nock and of forced irregular posture, which are duo to exposure to cold and muscular or neuromuscular involve- ment tiro concerned, electric treatment is par excellence favorable. Here the faradic cm-rent, or more particularly the static breeze, or induction- coil sparks are of groat service. Chorea. Treatment of chorea by electric energy remains a terra incognita in neurology. Certain cases of chorea are undoubtedly much benefited by electricity, especially by the static breeze, or application of induction sparks to the spinal cord, or galvanic baths; but the action is probably due entirely to the tonic effects on the body. Cases of chorea treated at St. Bartholomew 's Clinic have been quickly cured by the application of glass vacuum electrodes from the Oudin resonator along the spine and over the upper and lower limbs. If it be assumed that most choreas are. after till, the results of a post- infectious toxemia having a special predilection for the motor area, causing excessive 1 irritability, or bringing about insufficient inhibition, thru it is comprehensible why general electric stimulation by the static currents is as efficacious as it is at times. Furthermore, in the treat- ment of exhaustion states following excessive choreic movements elec- tricity is of inestimable value and should be added as an adjunct in the treatment of this affection by the ordinary tonic measures usually carried out. Pharmacopeal therapy, hydrotherapy, and electric therapy combined give better results than any one alone. Jones has found in the treatment of these cases that the application of the negative breeze to the spine is a convenient and more agreeable method of treatment than the ordinary static spark procedure. An .r-ray ex- amination of the teeth frequently reveals dental infection as the cause and points the way to a cure of the disease. Occupation Neuroses. These, as has already been said, are properly considered in the light of a complex etiology. They are cases of neurasthenia mixed with a bad psychic habit, and experience shows that in their treatment they are extremely obstinate. As is well known, such forms of occupation neuroses associated with (ramp- like conditions in the muscles are common accompaniments to piano playing, violin playing, tennis playing, and tailors, shoemakers, and writers are often afflicted with it. A vast number of neuroses belong to this group. Klect ric treatment is of service undoubtedly in the toninir up of the muscles themselves, but it is more than doubtful whether it ever reaches the psychic factor in the disorder. Our own experience ha- been very disheartening in the electric treatment of these occupation neuroses, especially writer's cramp. (idlrnnir Currents for Writer's Cramp. A large negative 1 electrode MKlMeAL KI.KCTHK'ITY AND UONTGEN KAYS is placed between the shoulder-blades and the forearm rests in a bath of tepid water in which the positive electrode is placed. A current of SO ma. is applied for fifteen or twenty minutes every day. Exophthalmic Goiter, ('mil the exact pathology of this disorder i- placed upon a more rational foundation it were futile to claim for ii that it may lie cured l>y electric measures of treatment. There are hers of cases in which electric application- of the induction cur- rent applied to the >ide- of the neck have proved to be of considerable Thr-e are probably those cases in which the uoiter is largely d [i to disturbances in the functions of the cervical sympathetic nerves, the electric treatment serves to restore in part at least a function which has been greatly altered bv t he toxemia of t he overact in milli- rcs. Th" treatment can be applied twice a week. Osier advises a thorough trial "t' the galvanic current for three or four months. The direct apphcat loii , ,| ;l -.park t rom a -t at ic machine has also been of ^reat service, but. of course, it is rather a disagreeable method of treatment. \\ h'-n this is used the patient is placed on the insulated platform in the KLKCTKIC1TY IN DISKASKS OF TI1K NKKVoFS SYSTKM ")21 l)rass hall elect rode, which is held in the hand of ihe op: rat or, is brought \vii hin 4 or 5 inches of the other end of the spark director, when a spark \vi!l jump. This is rather a severe treatment, but some case- have been great ly benefited by it . Treatment by the .f-ray and high-frequency currents has resulted in a certain percentage oi pernianeni cures in the author's cases. Hysteria. The attitude assumed on this question is a more or less radical one. It is highly important in the first place to distinguish between hysteria proper as a well-defined and carefully described psychoneurosis, and hysteric or hysterifonn symptoms which may be the accompaniment of a vast number of organic affections, not only oi the central nervous svstem but also the entire bodv. A characteristic feature in true hysteria is a certain foundation in character which permits of the ready dissociation of the personality, and it is. therefore, characterized by great emotional instability and a childish development, stamping the individual at once as a being more primitive than the education and environment would seem to show: in other words, the true hysteric character is a primitive character, and it is well recognized that true hysteria is much more prevalent among primitive people-, such, for instance, as i he natives of Java. Kraepelin has made a thorough study, the Alueriean negro, am tvpes. The hysteric character is never altered by electricity. manifestations of the dissociation in consciousness, such as the paralysis, anesthesias, etc.. are very frequently relieved by the electric currents, particularly those of a painful or shock-like nature. Those forms of energy are useful which make sudden unexpected de- mands upon the attention of the individual, and which for the time. To use Janet 's phrase, are capable of rousinu the nervous tension to such a point that the dissociated element in consciousness is brought back into the hierarchy of the conscious personality. With the cessation of the treatment, however, disaggregation takes place in another asso- ciation, other symptoms arise, and the fundamental features of the personality remain untouched. In fact, the wonder-working, -is it were, of the electric display only contributes to the receptivity of the individual to certain classes of impressions, which rend to perpetuate the primitive nature of the individual instead of affording any means of education. If the electric treatment is used only as a means to an end. an attempt, as it were, to first gain ihe attention of a very loosely aggregated personality, which is then worked upon by proper psycho- therapeutic measures, then its use may be advisable, but as pure elec- tricity it works to the disadvantage of the individual. The galvanic or faradic treatment of hysterically paralyzed limbs is. we believe, verv harmful to the individual. The element of suggestion that the limb is paraly/ed by the incessant working over it by electricity tends to perpetuate the paralysis and may make it permanent. On the other hand, so far as the treatment of hysteric xi/tnptonix, which are the reflex of disorders of an entirely different nature is con- cerned, electricity is often of a great deal of value, and when it is of service the attention of the physician should immediately be awakened to the possibility of an underlying organic cause for the hysteric mani- festations. Thus, the common association of hysteric symptoms with such disorders as tumor- of the spine, tumor- of the brain, abcesses ot 522 MEDICAL ELECTRICITY AND ROXTGEN RAYS different portions of the body, tumors of the kidneys, tuberculosis, float- ing kidney, stone in the bladder, etc., etc., all of which conditions are known to give rise to hysteric symptoms very frequently, should not be overlooked, and when these are alleviated by electric treatment the physician should not be deluded into belief that they are hysteric and that the patient is well, but the very fact of their being amenable to electric treatment should point in the direction of a further search for the cause of the hysteric manifestations. Thus, it may be seen that the electric treatment of these conditions offers a very important diagnostic clue. Mental Disorders. It is entirely too early to generalize upon the value of electric forms of stimulation in mental diseases. If it be of service at all. it is of some assistance in the treatment of depressed states, usuallv the depressed phases of maniacal depressive insanity. Also, perhaps, in the mild or severe depressions associated with senile or presenile psychoses in which the element of arteriosclerosis is the primary pathologic factor. It has already been pointed out that cer- tain forms of electric energy have shown themselves to be of service in the treatment of some cerebral tumors, and mental changes due to cerebral tumors are concomitantly helped thereby. It is beyond question, however, that electric forms of energy have no radical effect on any definite psychotic conditions, but as an adjunct in the general treatment of some of the psychoses electricity is unde- niably of a threat deal of benefit. And in the large groups of cases of the psychoneuroses, particularly in the neurasthenic group in which the mental state closely approaches insanity, electric stimulation, particularly by various adaptations of the static current, is of general tonic value. The exact limitations of electric stimulation of metabolism and the effects that such change in metabolic activity may have upon the development of psychoses are matters which are as yet in the realm of pure hypothesis. It is highly desirable that careful consecutive studies be made on definite forms of psychoses, so far as we believe that such definite form- do exist, in order that clearer notions of the value of this form of energy may be obtained. NEURASTHENIA The beneficial effects of electricity in tin.- di-ea.-e are of two different physical kind.- besides that due to mental impression. Practically all form- of electricity which are suitable for use in this disease improve the general nutrition and digestion. The urine contains more urea and le.-- uric acid and albumin and .-ugar it the latter are present. In ca -<- oi ma 1 nut ni ion wit h phosplmt una and a/ot uria elect rich v increases bodily weight and causes the urine to become normal. The effect, so far d> -'-ribi d i.- one of regulation ot cellular activitv and of a beneficial effect upon the central nervous system. Th'- -econd kind of effect from elect ncitv is upon the circulation, an : ':. ". \ be in the direction of causing an elevation or a reduction in bl oo' i -pre. --U re according to 1 lie form of elect ncity which is emploved. < ie>,, .;::'_'. extremely high-tension application-, like the static spark or \>r*-> /.< and the .-park or eflluve from the ( Midin resonator (the latter ^ivmiz a hr_ r h-frequency high-tension current ), increase the blood- ELECTRICITY IN DISKASKS OF THK NKHVOUS SYSTEM OZ.5 pressure, and while called for in cases with hypotension, are contra- indicated in neurasthenia with high arterial tension or with arterio- sclerosis. Comparatively low-tension high-frequency currents, like, those from the d'Arsonval apparatus, have a marked effect in lowering arterial tension, and are especially indicated in neurasthenia with hiuli arterial tension or with arteriosclerosis. Application of Static Electricity in Neurasthenia. It is not necessarv that the static machine should be of the largest and most powerful type, but it must work well and give- a good discharge between balls '3 inches or more apart. Static Insulation or Static Bath. The patient sits on an insulated platform with his feet resting upon a metal plate connected with the negative prime conductor, while the positive prime conductor is grounded. Treatments last for five minutes at first, but are increased to fifteen minutes, and are given every day. This is an excellent tonic to all the tissues in the body. Static Breeze. The patient is insulated as before with the negative pole, while an electrode from the positive terminal with one or several points is brought near some part of the surface of the body. The effect is a sedative one upon the central nervous system. For instance, the sensation as of an iron band around the head is relieved by a few minutes, application of the static breeze to the nape of the neck. A favorite application in neurasthenia is a static breeze from a crown suspended over the head and connected with the positive pole while the patient is negatively insulated. A reversal of this polarity causes a much greater prickling sensation in the scalp and makes it disagreeable. The positive pole is readily distinguished by the fact that the dis- charge from it to the negative pole when they are an inch apart may be diverted by a piece of wood, such as a match. Moving a piece of wood over the surface of the positive pole, one is enabled to make the dis- charge start from wherever, within certain limits, the wood touches or even approaches the positive 1 pole. The /;W//rr discharge follows vond. Another way is by the fact that a brush discharge of a violet light several inches long may be obtained from a pointed electrode connected with the positive pole of the static machine, while no discharge 1 is per- ceptible from a point connected with the negative pole until it is close enough to send a spark to the surface. Insomnia from neurasthenia often yields to a static bath with a head breeze, and so do all kinds of nervous apprehension and even delusions; but excessive 1 or too prolonged stimulation of muscular contraction by the static wave currents will cause insomnia. Static S/Hirkx. The patient is in negative insulation, and a metal ball electrode connected with the positive pole is brought near enou.irh to send a spark to the surface 1 of the body. This may be' applied through the clothes, and the 1 ball electrode should be approached with a sort of quick, striking motion, permitting only one spark to pass before 1 the electrode is airain beyond sparking distance. A stream of sparks at one' place is painful and exceedingly disagreeable. For a general tonic effect and to raise the arterial tension a series of sparks along the spine are 1 excellent. They cause localized contraction of muscular fibers and are indicated in pronounced muscular atemy, either ^enei'al or local. Static sparks applied in the left iliac region have a most beneficial effect upon the' constipation which is often a symptom of neurasthenia, and they al-o iv-toiv the 1 appetite and relieve the 1 general seMise 1 e>f depression. I no 1 i net Static N/v;/7,'N.- -For all the 1 purposes for which static sparks are applied, the effect may be obtained by grounding the positive 1 pole of the static machine (connecting it with the water or gas or steam pipes), and applvim:' the -parks from an elect vode which is also grounded. This make- the application much easier for the operator, since the 1 electrode i- not charged and need not be insulated. St'itir b"rii-tion or Mn.wujc. The patient is in negative insulation, and the positive 1 pole is connected with a roller electrode, which is rubbed over the surface of the body outside the clothes, or the same applica- catioii may be made indirectly, grounding the positive pole and the roller electrode. The effect is that of a continuous shower of sparks, the length of which is determined by the thickin-- of the clothing. The application is a severe one and makes the strongest man twist and -quirm. The electrode should be moved over the surface quickly and ; not be applied for more than a few seconds at a time. Pron 1 ha- most admirably epitomized the 1 indications for static, faradic. and galvanic applications in this disease 1 . He considers static massage as ii-eful in cases with anesthesia en plaques and with spinal cord irri- ti. causing seminal emissions and cramps and exaggerated rellexes. The applications are made to t he upper part of t he body. 77'" >'/r//,V-,' nil /in il ( 7//-/V///. The pelvic neuralgia of neurasthenia in women i- almost al\va\> relieved by vaginal applications of the st at ic- ed current. Albert -\VeillV met hod of application is by a vaginal electrode connected with his rheostat for controlling the strength of the -' at ic-induced current. The operator holds the insulated handle of this electr,,de with one hand while he massages the abdomen with the 1 it In r. The application should be as strong as can be borne without discom- fi Hi. The symptoms especially calling for treatment by static electricity and mvasthenia. Faradic Applications. These are not made with a view to causing ilar contractions, and the current must, therefore, be a weak one and preferably one with the most rapid possible interruptions. The . i"er an a-ily si cured if the faradic coil is made with a ribbon inter- : ipter. \ trip of steel tape is the vibrator which interrupts the pri- mary CU;TI nt. It i- permanently fastened at one end and mav be 1 turning a screw at the other end. The tenser the steel ' i are the vibrations produced by the action of the ' which i- placet) oppo-ite the middle of the ribbon. The ",<'!' lie -uccession of induced current.-, the less is the effect .'i ';.'. . . ;tr contraction and the greater i- the tonic effect upon vstem. The faradic coil slienild have an adjustable (he secondarv coil and the greatest number should ELECTRICITY IX DISKASKS OF THK XKKVol'.s SYSTKM ceptible polarity, t>ut this is so very slight that cither electrode be used indifferent ly. (rencral faradization is useful in eases of neurasthenia. The patient sits upon or lets his feet rest upon a large sheet of metal covered with wet flannel as the indifferent electrode. The other electrode is passed over the forehead, the nape of the neck, the spine, the precordia, and the abdomen. This active electrode may consist of a damp sponge electrode or it may be the operator's hand. In the latter case the operator holds a metallic or sponge electrode connected wuh the active pole and the current passes through his body to the patient. The treatments last about ten minutes. Heard considered general faradization as especially indicated in neurasthenia with myasthenia and malnutrition, and that it should be avoided in very excitable neurasthenics, for whom static electricity seems to be better. Loral Faradization. Krb's treatment for cerebral or spinal neuras- thenia is by local applications alone of faradization for only two to five minutes. Bladder symptoms of a paralytic type in men may be treated by faradization with the indifferent electrode on the abdomen or buttocks, and the active electrode applied to the perineum and scrotum succes- sively. Rapid interruptions and a fine secondary coil are used. The pelvic neuralgia or neurasthenia in women is best treated by static electricity applied intravaginally, as has been described on page ")24, or by vaginal faradization. For the latter, sponge electrodes are held in the vagina and over the abdomen. Very rapid interruptions and the maximal strength of current are used for ten minutes each day. Galvanic Applications. (Icncral galvanization is applied from a large indifferent negative electrode applied to the feet and an active positive electrode rubbed over different parts of the surface. Two to four milliamperes is the proper strength of current. Such an applica- tion is not very often employed. ( '< ntral t/ah'aniz to 10 ma. is used, but it must be gradually turned on for each position of the active elec- trode, and graduallv turned off before the electrode is removed from each place. The strength of current may be a little greater at a distance from t he head. Lni'nl (lulvnnizution. The uniform and uninterrupted galvanic or constant current is used for two or three local conditions. Abdominal neurasthenia is successfully treated by a laruv kaolin pad under the back and one the si/e of an outspread hand over the epigas- trium. 100 to 1")0 ma. sinusoidal, 2S to the minute. Impotence from neurasthenia in men may be treated by a cm-rent of 10 to 20 milliamperes, flowing for fifteen minutes between a larue indifferent positive electrode at the genital center in the spine, and an active negative electrode passed over the perineum, scrotum, spermatic f)2<> MKDICAL ELKCTKU'ITY AND KONTCEN KAYS cord, and the root of the peni<. Albert -Weil sometimes terminated each treatment by rhythmic galvani/ation. Treatments are given daily. Impotence is a condition in which the discovery and removal of the cause of the trouble is extremely important. Such a condition as hemorrhoids or rectal ulcer may interfere with the -access of any treat- ment directed toward the genital organs alone, and then again every one reali/es the profound influence of the mind over this condition. Cnnxti'iMitiun.- This i- almost always a condition of spasmodic con- traction in neurasthenia and is relieved by the constant current of rather high amperage (l/i or 20 milliamperes through large electrodes) over the abdomen. Oilier means are tlie static spark to the left iliac fosO[. rhythmicallv varied and reversed currents, and galvanofaradi/a- t ion. ('< /ilnili/' ( ; to 10 milliam- peres is turned on gradually and allowed to How for five or ten minutes. It is turned off just as gradually. I I-TIJ IIc'ii'i/ (idl rnitic ( '"/'/v tttx fo/' ('oiixtipntion in \ cnTuxthcn m . '1 his method. Used by Hartenberg, 1 has not yet been generallv tried. The patient is seated upon one electrode, and another as large as possible i- applied over the abdomen. The current is of [o volts and 200 ma. and i- applied every thirty seconds for an instant, first in one direction and then in the other. Vigorous contractions of tin 1 abdominal and intestinal walls lake place. There i< no irritation of the skin. Forty such double shocks ^closure and opening) are applied at first every (lav. ( till 1'Hinr ( 'u/'t'i iifx Inr 1 1 1 iiilii<-h< in \ (/Tons I )//.-- [it />*/n.- A current of x t.i I'l ina. i- applied witli one electrode at the nucha and the other on the forehead. High-frequency currents lm\e become a mosl important factor ;:.:.' oj neurasthenia. The general indicat ions as to tension been alluded to. 'I he d'Arsonval, or low-tension hiidi- ' . are -mied to cases with hi'_di arterial tension, and lh< ' >udiii and oilier hi^h-tension hinh-fre(|uenc\- currents are. suited, 1 v a rt erial tension. ' mi. for fliijli-l'i't '/in nrif ( 'urn nfx in \( iiffixthcniti. /' -; nn bv high-tension hnrli-H'ci juency currents i.- more than any other method except m cases with high \ bipolar otcnrc. One high-frequency application suited to this symptom in male neurasthenics is from a bipolar resonator, with an efnuve over the epigastrium and a spark electrode applied over the genital center in the spinal cord. The author has had successful results with a monopolar application from the Oudin resonator and a glass vacuum electrode to the penis, scrotum, and groins. A strong application is employed, regulated so as to produce a current which makes the glass quite hot. but with very little spark effect, powder being used to enable the electrode to slip smoothly over the surface without breaking the contact or producing perceptible sparks. \o effect may be noted at the first treatment, but during the subsequent treatments the erections become extremely vigorous. Functional power is restored, but whether there is a relapse depends upon the patient's general condition. A further consideration of the u.-e of high-frequency current.- in this disease is found on page 587. MMDH AI. KI.K< TKK ITY AND KoVl < . I IN KAYS ELECTRIC SLEEP AND ELECTRIC DEATH Electric Sleep. Tin- i- ;i name ^iven in ;i t'nmi <>t anesthesia which Si rphane I.ediic has been able to brim: abniit in annuals ami in man as a !'-;:' < >! i he application ni' a type nf elect ric current which In 1 himself has devi-ed. The current ha.- already been spoken of in the paragraph nil local anesthesia ami the t ivat ment 0$ neural irias. 1 1 i.- an intermit tout current ni' low tension and nf infrequent interruption, which passes re !>i xly nf the animal. The interruptions in the nt. as has alreadv been stated, run from !M) to 1 HI per second, and the electromotive fnive rarrly exceeds '.->() volts. The strength of cur- rent i- 4 ma. The apparatus is described on paize 4'.H. l.educ \vas alile. in p.tO'J Oil, to briim' aliout complet<' narcosis in ils by the application of his current directly in the cranium, one electrode bejuM- placed upon the head and the other either upon the extremities nr over tin' abdomen ol the annual. The de-criptimi nf whal take- place can perhaps be best told in his own wnrds. fni 1 he made liimself the subject, nf an experiment and his assistants placed him under ireneral electric anesthesia. The results nf his experiments were communicated to the French > icii ' de Binlnu'ie. XnN'ember '2'2. I'.iirj. and in the Archives d'Klectricite ::. ' lii-ale. July 1"). l!M):>.h<.' ii'ives us a description nt Ins own sensations when passing into the electric anesthesia. ( >ne laru'e electrode fnrmed of absorbent cotton impregnated with 1: HID solution nf chlorid of sodium, witli a metallic plat*' behind, is placed on the forehead and fastened to the head. Tin- frontal electrode i- the cathode. A larger electrode made m the same manner is placed over the hack and fastened there by mean- of an elastic band. The current is then turned on. beim:' interrupted for the first tenth period of application one hundred times to the second. The - n-ai ion produced by i he stimulation of i he superficial nerves, although -liiih'l; disagreeable, can be easily endured. After ;; -hurt tiin<' the patient feels a calm -imilar to the sensation ;i continuous curi'i'iit. and tin-, after having passe of hi> own impotence and iiuihility to communicate with his colleagues. The contacts, the pinching and the pricking in the forearm, could lie felt, hut the sensations were much diminished, as in .a very large swollen member. The most painful impression was to notice the dissociation and the successive disappearance 1 of the faculties; the impression was identical with that which one feels in a nightmare in which, in the presence of a great danger, one feels that one is neither able to cry out nor 1o make any movement . In his first experiment consciousness was not entirely abolished, but in a second seance his colleagues advanced to the point where, so tar as they were able to determine, consciousness had lapsed completely, but heduc was able to feel that this had not really taken place because there was not complete suppression of all sensihilitv. The electromotive force had been raised as high as oo volts, the intensity in the interrupted circuit being 1 milliamperes. In each one of the seances he remained twenty minutes under the influence of the current. Awakening was instantaneous and the after-effect was a mild state of exhilaration. With animals, however, as has been shown by Leduc and his pupils and by many other observers, the electric sleep may be prolonged for considerable periods of time for three or four hours at least and operations may be performed upon them. Certain points have been brought out with reference to this electric sleep which, although as yet not definite, may be outlined at this time. In order to produce the electric sleep according to the experiences which have thus far been reported, it would appear that the ordinary street current is not as valuable or as safe, it would perhaps be better to sav as a current which is delivered more equably, as from a storage- battery. The street current which charges a storage-battery and i.- utilized from tin-re would be the ideal current. The arrangement sug- gested bv a number of experimenters would be to utilize the storage current for the electricity which is to traverse the body, and the street current to run the motor of the interrupter. (Iradiial application of the current is to be preferred to an abrupt ( losage. The negative pole, the cathode, should always be applied to the head, for experience lias shown that if the anode be applied to the head grave disturbances in respiration take place and the temperature is apt to go up. ( 'ert a in coi i di I ions are observed to be nmre or less constantly present . Thus the pupils are usuallv contracted durum' the stale ot electric sleep. The temperature is usual!}' about normal or slightly above. lli' 1 res- piratory rhyt hm is slight 1 v hastened. There is usually an increase in tin 1 arterial | iressure which seems to depend upon v a so mot or cause-. ( VIM am of the reflexes seem to be exaggerated, while others are diminished. In overdosage, leading to an electric epileptic state or to electrocu- tion by the Leduc current, the blood-ressure Mif'fer.- a ver marked O.M) MEDICAL ELECTRICITY AND RONTGEN RAYS Whether the Leduc current can be used to advantage in electro- cution of the human being is for the future to decide, but there arc certain facts which point to its desirability in this direction. As to it< applicability in man for anesthetic purposes, the future alone will be able to determine. At the present time of writing the fact< brought out by the application of this new type of current are of extreme theoretic importance, but it has not been tried in a sufficient number of cases to justify any general statements concerning its applic- ability for general narcotic purposes. Local Anesthesia from Electric Currents. This has been obtained by II. ( liin/el. 1 u-ing a direct 2~) to oO volt current of 2 to 10 ma. inter- rupted 2oO times a second. The anode is placed on the skin over the painful spot and the cathode at some indifferent place. He has found it effective in migraine, bronchial asthma (with the anode on the neck), and aniiina pectoris. Electric Death (sec also page 3li~i. Internal lesions in death due to industrial electricity pathognomonic lesions for the most part have been absent in these cases. Numerous experiments have been made on animals to determine the causes of death and the character of the lesions. The earliest experimental investigations made on animals with the modern industrial electric currents that are of service in the present pres- entation were those of (Irange, (lariel, and Brouardel, made 1 in 1884, and those of B.rown-Sequard and d'Arsonval 2 in 1S8(> and 1887. It r-hould be borne in mind, however, that Priestlv, as early as 17(ib', killed animals by static electricity, and that at that time numerous experi- menters followed him, notably Fontana. the Italian physicist. The experiments of Xothnagel in l^M) are also worthy of record in this relat ionship. D Arsonval's results will be referred to under the paragraph on Causes of Death, since he was interested in the physiologic side of the problem only. From the pathologic point of view the investigations of Peterson and Doremus, conducted in the Kdison laborities in ISSS, are of interest. Animal experiments made by Kratter a within recent years on mice, sruinea-pigs, rabbits, cats, and dogs show certain signs regarded by him ::- more or less pathognomonic of the condition. Subpericardial and subpleural ecchymoses and. more particularly, subendocardial ccchy- motic extravasations occurred in mo.-t of his cases, combined with bloody emphysema o| the larger bronchial ramification-. These signs, : u ': : :. iii conjunction with the external burn.-, are believed by him 'lent to make the diagnosis "death by electricity." Riu'or - \ ry rapidl v and persisted for a di-t inct period of t ime. in ih" brain and spinal cord were not prevalent, \vere subdural and mternieningeal hemorrhagic se are of interest ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 531 other recent writers would seem to prove quite conclusively that such do not occur save at the sites of electrode contact. Cunningham 1 has shown that if the thorax he opened immediately following death due to strong continuous currents, the heart on close examination will be found to show a minute quivering throughout its entire muscular substance. While the coordinate beats of the ventricles, as a rule, are absent, the numerous isolated bundles of muscle-fibers will be found alternately to contract and relax with vigor in different parts of the ventricle; and as the right and left auricles become gradually distended this irregular quivering of the muscle bundles grows feebler and feebler, until every trace of muscular contraction has disappeared. This state of delirium cord is or, as Cunningham prefers to call it, "fibrillary con- traction," as the cause of death was first pointed out by Cunningham, and also independently by Pn'vost and Battelli. 2 The nervous tissues have been carefully searched for pathologic changes, and it has only been within recent times that distinct changes have been found. It seems not improbable that changes of importance would be found by the newer technical met hods of investigation, but thus far only a few workers have employed the Xissl methods, or modifications of the same. Kratter's observations were made by the older methods, and he found no special cell changes. He confirms the observations made by Peterson, Spitzka, Van (lieson, and others that minute capil- lary hemorrhages in the perivascular spaces are present, especially in the superficial layers of the cortex, but these he distinctly shows are not universal, and cannot be regarded as of sufficient moment on which to base a pathologic diagnosis of death. He concludes, however, that he believes that minute changes, not known to our present technical methods, arc responsible for death by electric currents. More recently Corrado 8 has shown that such minute changes may be demonstrated by means of the more modern histochemic methods. Con-ado's conclusions may be summarized as follows: The continuous electric current derived directly from the commu- tator and applied to robust adult dogs weighing from 2.5 to 20 kilos (5 to 50 pounds), one electrode being placed on the head and the other on the lower portion of the spinal cord, with a voltage of from 720 to 2175 volts, and an amperage of 20 to 30, or in two dogs. 10 to 12 amperes. produced death in every instance. Death occurred immediately and was not influenced by artificial respiration,. On the closure of the cir- cuit the animal, without emitting a cry, became rigid, and all the mus- cles, especially those of the back, contracted violently, producing a pronounced opisthotonos. This rigidity persisted for from one-half to one minute after the cessation of the flow of the current. Kespira- tion was arrested from the first moment of the passage of the current. An examination of the ganglion cells of the brain and spinal cord by the newer methods of Xissl and also by the method of (iolgi showed a number of interesting lesions, the importance and interpretation of which are only just beginning to be appreciated. Corrado describes changes as occurring in the external shape and ' New York Medical .T<>urn;il. Oct. IX lvi). pp. oSl, tilt'.. J Comptes rcndu- dc 1' Academic dcs sciences. March lo. 27. ls ( ,H>. 3 G. Cnrrado, I >c alcunc altcra/ionc dellc cellule ncrvosc nella morte per cllct- trinta. Atti. d. K. A^sad. nicd. ( 'hir. di Napoli. 1MN vol. Ixxv. \i. i:u:< run ITY AND UII.NTCKN KAY ly. chanties of the cytoplasm and of the A. Changes in the Cell Contour. (1) Noteworthy and various deformit ie-. erosions, jan^ed outline.-, laceration-, and e\'en severe destruction of the cell outline. rJ) The contour of the cell became ha.'v and diffuse. (.'!) In some cases the protoplasm became granular on one -i<[< . H. Internal Cell Changes, ih A jirade r t dissolution of the chro- matic substances with powdery granulations was observed. The cell contents were more homogeneous and showed the beginning changes of chromatolvsis. cJ) l-retnient and pronounced vacuolation (perhaps artefact). 101 The chromatic substances had a .-light tendency to 1 mie dispersed in the remainder of the cell-body, at times in distinct, lions, \\lndi in certain parts ot the cerebral cortex had a special arrangement. Then- collections of chromatic particle- were not dis- [> ; in the ilireciiuii of th" pas.-a^e of the electric current. (I) The 'i"'" I'-i-taiit. It may. however, be modified iii shape, in si/.f, or may i-ntirely di.-appear. The contour '. be irn ^ular ore \-en angular. The chromatic sul>st a nc '' 'h' 1 : "' ' nia\ In- irreu'u'arly di-posed. granular, arranu'cd in line a I 1 he periphery, or ii may i Ml irely disappear, lea \-iim' Tin- po.-ii ion of i he nuclcii.- mav vary. A cer- 1 ' lor il lo be located on < me ,-i(|e, especially to 'he accumulation ,,\ chromatic subslaiiees occur.-. may be bmken. ,"i Die nudeohis i.- the "f 'he cdi. I' - tor the im.-i j i; ,n preserved and 'i the remain' i' r of t he n || i . profoundly- altered. ' ' 'H -i/e. li has a lendi ln-\ to an eccen- 'i '"it to the periphi n of i he nucleus or even loth. F.l.Ki TinciTV IN DIs-F.AsKs OF TIIK XKKVOT ,Y>TKM Cornulo ;ilso describes a sci'ics of changes it) specimens treated by 11 ic ( lolgi met hods. These 1 cl unices of t he dendrites eonsisl for t he most part of varicose atrophy, fragmentation, and other modifications of >ha|>e and position. Since the (lolgi method and its no\v known modi- tications show precisely such ch;i Hires in normal material, it is fairly well established, by reason of this and also on account of the great lack of uniformity in the (lolgi ])ictures, tliat it is unwise to describe these as degenerative lesion- pathognomonic of any diseased condition. Hence, these observations of CoiTildo by means of the (lolgi method are not considered final. In man the pathologic features have been closely followed, though not as yet by the newer methods. Electrocution has given the most accurately observed cases, and the investigations of Spit/ka, Van (lieson, and Kratter are the most elaborate 1 . In the case of William Kemmler, the first officially electrocuted criminal under the modified statutes of the State of Xew York, the following autopsy record is taken from the notes 3 , \fe J ~- : s~ ' -& *A*-'Z ~^ f ) Fie. .'vSl.- Sliii\\!nt: tlit> character JUKI distribution of tlio potcrliial sprits on the floor of the fourth ventricle in the ease ol Sehiehiok Juirisro (Nan Ciies of Dr. ( leorg' 1 V . Shrady: "( 'apillary hemorrhages were^ noted on the flos; of the fourth ventricle, the third \cntricle, and the anterior part of the lateral ventricles. The circumvasciilar spaces appeared to be distended with serum and blood. The drain cortex beneath the area of contact was notably hardened. The vessels of the corpora Mriata were notably enlarged at different parts of their ramification-. The pons was slightly softened The spinal cord showed no gross lesions." The abstracted report U'liiLi due i ) manipulative artefacts. 1 ardening. etc.. and cannot !" brought into correlation with the later-da\ pathology ot the ganglion 00 4 MKDICAL KLKCTRICITY AND RONTdKN HAYS <('!! (Kwing, ( loldscheider. Turner, Barbacci, etc.). The histologic examinations of those paying the electrocution > The occurrence and distribution of the te hemorrhain'c spots are not uniform or constant ieatures in these casi - and, as they are found after death from a great variety of causes, thev cannot properly be regarded as positively characteristic of death i- method." ( >bservations on man. wh'di can be Used to compare those of ( 'orrado on dogs, are still lacking. for man it cannot be -aid. therefore, that the observations ol ('orrado on dogs ;ime when tin- uods were ilispleased with ilie children of i, -peculation has been rife upon the question as to bv < lect ricjty. I he earln-r ol erval ions ha\'e been j i. and '.'.' are indebted to him for a lar^e number of \moir_; t he earlier i ! i.-ervi TS ' . the " itlst at]! alieoll- i eved that t lie act i< >l\ \\ a- i, . '. at ion of t he ii' r\ on- ELECTRICITY IN DISEASES OF THE NERVOUS SYSTEM 535 amplified. It is worthy of mention in passing that Priestly, in 1760, and Fontana, in 1775, made a number of elaborate experiments. The modern epoch of experimental work may be said to have been inaugurated by Xothnagel, of (iermany, in isso, by Brouardel, (! range, and (lariel, in 1SS4, in France, closely followed by Brown-Sequard and d'Arsonval in 1SS7, by Knitter in (lermany, and by Biggs, Donlin, Houston, Jackson, Knapp, Peterson, Robert, and Terry in America, with the later studies of Tatum, Jones, Bleile, Oliver and Bolam, and Cunningham. From the pathologic point of view the work of Xissl, Hodge, Levi, Lugaro, Mann and Corrado Ms to be borne in mind. From the foregoing it may be seen that the entire possible theoretic ground was covered by the earlier observers, but their investigations lacked the precise experimental evidences demanded at the present time. The investigations of Xollet. Crange, d'Arsonval, Cirassct, Dubois, I.educ, and others mark the earlier steps in the progress of the elucidation of our knowledge concerning the phenomena of death by electricity, while the investigators just mentioned have brought the question to the present time with some definite conclusions. d'Arsonval 's and Brown-Sequard 's earlier hypotheses were received more widely than those of the other writers, and have been extensively quoted, but within recent times many of their conclusions have been questioned. d'Arson- val taught that death was produced in either of two ways or, perhaps, by the concurrent action of both: (1) By direct action, during which the disruptive action of the current produced mechanic alterations in the tissues and thus altered their physiologic activities. (2) By indirect or reflex action, whereby the important nerve-centers of the medulla were affected in their physiologic functions, which induced death. Brown-Sequard later amplified this indirect action in the nerve- centers. d'Arsonval again brought up the question, first promulgated by (irange, that the electric current could brimr about effects simulating death, but the subject could be revived by artificial respiration, to which reference will be made further in the discussion. Cunningham 's 2 very able summary of the experimental data fol- lowing the epoch of d'Arsonval is here very freely used. The researches of later writers (dearly led to the conclusions that neither the results of experiments on animals with strong electric currents nor the numer- ous reports of pathologic findings in the bodies of men killed accidentally by the electric currents of commerce or legally electrocuted by the high- tension current employed by the authorities in Xew York State, are in the least corrobat ive of the hypotheses of these French investigators Cunningham 's experiments bear out the conclusions of the later writers, who find that in the higher animals the chief lethal effect of both the ous and the alternating currents ^ due to their action on the Thus, in order to bring about fatal results very much stronger - are necessary when the electrode- are applied to both sides d. A complication of the problem arise- Irom the lact that may lake place in different ways, according to the path traveled electric current. Thus the work oi Cunninii'ham and others has of a strniiii current through the exposed brain and upper spinal cord, t he let ha 1 effect i- plainl v t he iv.-ult of a.-ph y xia. while in a second class, where the course of even a moderate current traverses the heart for a brief period only, the deadly iv-ult is due to the interference with the coordinating power of the heart, which laker- place suddenly and is permanent, causimr the central nervous system to die ot anemia. A corollary of thi- fact i- the indication that death bv electrocution could isi d in a -horter time and with greater certainty it the electrodes were -o pk-t'-ed ihat the greater jiart of the electric current were made . > r-e i lie heart directly. The cerebrospinal arc -hould be included, yer. in the path of the current in order to still the respiratory as well as the cardiac movements. A.- pointed out m the sect ion on Pathol- ogy, the hear; in animal- killed by electric current is found to show a condition ot "delirium cordis " or "fibrillarv contraction. ' This at Nad- Cunninirham to assert that death by commercial electric currents, as well as death by electrocution, is due for the most part to the fact that the electric current induces fibrillarv contractions of the heart. The -ummarv ot conclusions bv Cunningham i- here given: 1 Indu-tnal electric currents, which traverse the whole bodv trans- versely or longitudinally in sufficient intensity, kill because fibrillary contraction of the heart is produced, and not, as lias been hitherto -urmi-ed, by producing a total paralysis of that organ or by killing oiitriirht. >'2 Such currents neither kill the central nervous system outriirht nor paralyze it instantaneously. Death of the nervous system from -uch currents is due to the total anemia following a sudden arrest of the circulation. (/>i In rare cases, when an electric current traverses only the cerebrocervical portion of the nervous -y.-tem in considerable intensity and for a considerable length of time, it mav kill by asphvxia, consequent on a more or less complete inhibition of the respiratory inent.-. wliich occurs chiefly during the passage of the current. Xo exist mg facts warrant the conclusion that the medullary respiratory 1 nt i r i- paraly/.ed or killed in -uch condit iohs. 1 i h I m lust rial currents are practically non-lethal to frogs and turtles, as the condition of lat ion <|ii ickly and spontaneously disappears from their heart s after the current has ceased to pas-. Such animal- can, of course, be killed bv Mired a ppl i cat ion of a current of moderate intensity or by ine ij enormous volt age and large intensity. (o Si ron^ elect ric in" 1 I ' ! to the surface of the skin affect the heart in the same ' irn nt.- "i |es.. strength do when they are applied directly ilii It may be pi i-sible l'i r an elect ric current 1 M-ity and elect romol ive lorce to produce instantaneous li-rupt ive act ion or by pn > an in.-taiit aneous the cellular con.-t il uents of I he I >oi |y. I ndu-t rial . di a- a '. - /: of I In ir acl ion death I he e\pe| ience of indi\ idual - \\ ho ha ve recovered hat -iic'n a mode (,] 1 1 ( -at h is no! a KLKCTHICI'I'V IN DISKASKS OF TIIK NKKYOTS SYSTKM .').) t observers -Cunningham, Prevost, and Battelli have come to similar conclusions, it seems that the question of the cause of death by electricity ha- an authoritative answer in the conclusions just quoted. The experiments of Prevost and Battelli, pat^e '.M\, are of the greatest value. They show that with the same position of the elec- trodes current- measured in hundredth* of volts kill by cardiac fibrilla- tion: and currents measured in thousands of volts kill by respiratory paralysis. HIGH-FREQUENCY CURRENTS IT will be ivnirinbrivtl I hut when a discharge of electrostatic enemy take- place from a I.eyden jar the spark does not represent a single exchange of the exact amount required to equalize the electric condi- tion of its two armatures. On the contrary, the state of equilibrium is reached by a series of oscillations back and forth at the rate of about ,">i ii i.i H ii i a second. This is somewhat analogous to the experiment with the pith-ball suspended between a positively and a negatively charged body. The ball swings back and forth, carrving each time a fraction of t he charge from one and taking it to the other body, where it neutralizes that amount of elect ricity of the opposite siirn. This back-and-forth transference continues until both bodies are in the same electric condi- tion. The oscillations occurring in the case of a discharge between the positively and negatively charged coatings of a l.eydeii jar. or of a battery of I.eyden jars (acting as the condenser of an induction-coil, for example) are infinitely more rapid than the oscillations of the [stratum. The relative electric condition of the t \vo - i-M-oes ."iiio.uiii) alternations a second, and if the human connected wnh both armatures the application i.- quite different 1 . Ivaiiic or t'aradic current. It i- more analogous to ; breeze than to anvthilig else, but at the same time v ' the In-! liiidi-frequency apparatus a current of from 100 to 500, or ~o] ' ' 1 1 ii H i of more, inilliamperes pae- through the patient. I i-urn ' i- of incomparably greater volume of amperage than that v. :.: ' tween the pole- o| the ino-t powerful static machine. Tin ' ' pat ient i^ due to t he -elf-induct ion in 1 he coil uniting the t \vo I.. r-. which forms an e-v-ent ial part ot all hiu'li-frequency appai . . A -imp _' ot high-tension electricity i- undirectional, and I _. . ' - the way m whieh the strength of current uradually dim',: I ji. ''>'>- ' o-cillatory chai'acter Lii\'i'ii to t he discharge by 'ii o] I ,i vden jar.- and a -olenoii 1, I "he 1 1- : t he I'urrent -. u-ua ll>" ret erred to a- hiu'h-frecjuency i'Ai o md Te-la current -. are of t he HIGH-FREQUENCY CURRENTS 539 typo above described and are called damped oscillations. This is lo- calise they quickly diminish in extent and die out, while undamped oscil- lations are uniform in extent. High-frequency currents with undamped oscillations are referred to under the heading of DeForest Needle and Duddell's Singing Arc (page 640). The Direction of High-frequency Discharges. The discharge of a Leyden jar may be made up of millions of oscillations, but if it is charged from a non-alternating source of electricity, like a static machine, the first and strongest oscillation is always in the same direction. The latter is also the case with high-frequency apparatus actuated by an induction-coil, because only the break discharges of the latter are usually operative; the weaker make discharge is unable to charge the condensers to the discharging point as indicated by the length of the spark-gap. The Fleming Rectifier for. High-frequency Currents. This con- sists of an incandescent electric lamp in which there is a little metal cylinder besides the carbon or metallic oxid filament. Alternating high-frequency currents can pass through such a lamp in practically one direction only. When the filament is incandescent the partial vacuum in the globe becomes much less resistant to the passage of a current. The filament acts as a cathode, while the metal cylinder has a comparatively small surface for the radiation of cathode rays during Currenf Neq Wehne/t- Infcrrvpff . Apparatus for high-frequency current the period when the current seeks to flow in the other direction. Tin 1 incandescent lamp is lighted up by the current from a storage-battery. It is necessary to recharge the Leyden jar- e:ich time that they are discharged, so as to produce 1 a certain cont inuit y of effect in therapeut ics. The rate at which the Leyden jars are charged and discharged is only a few hundred or a few thousand times a minute. The 1 rate of o-cil- latioti in each individual discharge is million- of times a second. It is the latter rate that gives the name "high frequency" to these current-. At the present time it is not possible to obtain directly from any make of static machine or induction-coil a high-frequency current. In MEDICAL ELECTRICITY AND Ro.NTCEN HAYS order id obtain a hiu;h-frequeney current fniin either the static machine or induct idii-cdil it i- nece--arv 1 have an additional piece of appara- Mi-. The term "hiii'h-frequency current" should alway- have in addition the name which de-imiate- it- particular type. -iich as d'Arsonval hi>> illu-t rates a complete arrangement such as \\ill be nece.-sarv to produce t he d 'Arsonval current from the 1 10- volt direct current : posit ive and negative indicate the 1 10-volt direct ciiri'eiit. then comes an ordmarv double knife-switch with fuse. Tin o.-itive wire i.- conducted to the platinum point of the \\'ehneit, inti . tpter. T:.,- consists oi a 41 D'Arsonval and Oudin High-frequency Apparatus. D'Arsonval also made what is known as the large solenoid. Dr. Oudin found that by connecting one end of the large solenoid of d'Arsonval with on<- end of the small solenoid of d'Arsonval, as shown by Fig. 33)4, that from 1 he terminal he obtained a current entirely different in character from the ordinary d'Arsonval current. lie also found that by adjusting the con- tact point between the large solenoid and the small solenoid he was able to regulate the discharge from the terminal 0. This led him to construct what is now known as the Oudin .Resonator (Fig. 335). This you will see is simply a combination on one tube of the small solenoid of d'Arsonval and the large solenoid of d'Arsonval. In this construc- tion, however, it is arranged so that the contact F is adjustable and. it is found that when it is placed at a particular point the discharge from terminal is at its maximum. As this contact-point is moved above or below this particular point the discharge decreases. When it is adjusted to produce its maximum effect the apparatus is said to be in resonance. Another arrangement for obtaining high-frequency currents consists in what is known as a high-frequency set. This is designed especially to operate from the 110-volt alternating current (Fig. 33(>). It makes a somewhat more simple construct ion than the usual induction-coil ar- away with the electrolytic or mechanic inter- fact that the current is alternating. In this arrangement, instead of the usual open magnetic circuit type of in- duction-coil, the closed magnetic circuit type is used. The alter- nating current is conducted to the double pole knife-switch; then one terminal is carried to either the metallic rheostat or what is known as an inductance regulator. This is then connected with one end of the primary, the other end of the primary to one terminal of the ammeter, the other terminal of the ammeter former back to the main line. The secondary circuit is connected with the Leyden jars, which are connected with the Tesla coil. The current is regulat ed by means of t he induct ai ice and the lengt h of spark-gap. In place oi a IVslu transformer the secondary can be connected with an Oud m resonator. At the j> resent linn- ii is not possible to obtain a hiirh- t frequency current in any other than l>\ the above or similar means. 542 MEDICAL ELECTRICITY AND RONTGEN RAYS to have the arrangement of d'Arsonval, the 1 arrangement of Tesla, or that of Oudin in addition to the static machine or coil. I call atten- tion to this particularly, as some manufacturers claim that their static machine will give a high-frequency current direct. They use in con- junction with the static machine a vacuum electrode, and, as a rule, it is connected up as >ho\vn by Fig. 338. When the vacuum electrode is placed in contact with the patient it will light up with a violet color thr >ame as it would it' attached to a high-frequency apparatus, but the sensation produced in the patient is entirely different, being of a vibratory character; it i>. in fact, when used in this way in conjunction with a static machine simply a method of applying the wave-current by means of vacuum electrodes. This cm-rent has a certain therapeutic value, but should not be called a high-frequency current. It will be referred to as vibratorv current l Figs. 338 and 339). Fill. ;Wed with .-tittir machine. ( )ne very simple test to demonstrate physically the difference between this current and either form of high-frequency current is to have the subject in good contact with the metal part which holds the vacuum electrode. When this is connected with the static machine as above de.-cribed. you will experience a very disagreeable shock, wherea.-. when it is connected with a high-frequency current no sensation other than that of having a slight feeling of warmth will be experienced. mi electrodes, are used in this same way with an induction-coil, 1 m tii ' tji.M wiicii vinriitorv cum-nt i 1 - IIM-I! fr '!i oi irrent beniir regulated bv the distance A and B an te the fact that this current is not a hiirh-fn nece-.-arv to in.-ert between the electrode an< in-i rument as t lie oscii n HIGH-FREQUENCY CURRENTS 543 340 shows tliis in circuit with a Tcsla current. With the static machine you will notice that the violet color is all on one side of the center, whereas when connected with the Tesla current it shows the violet color on both sides of the center. An induction-coil, such as is suitable for x-ray work, is very desirable for high-frequency apparatus. A 12-inch coil is about the best, and can be used no mutter what the nature of the interrupter and the source of the primary current are. The primary winding of the coil should have a large number of turns so as to give great self-inductance and a proportionately heavy secondary discharge. In this case the actual spark length seems to be of less importance,' than the "fatness" of the spark, and in my own apparatus the best results are obtained with an adjustment which will produce a u'-inch flame between the poles of the coil when the high-frequency apparatus is disconnected from them. Kvery x-ray coil should have a variable primary winding, and if this is the case it will be easy to adjust it for the best high-frequency work. A desideratum is an interrupter which will produce a sufficiently heavy spark with only one, two or three, four, or five amperes of primary current. This means less wear upon the apparatus and longer continuous use without detriment. OS-cope demonstrates oscillatory character current. )f Tesla, high-frequency With alternating currents an .r-ray coil with one of the rectifiers described on page 723 works very well, or (iaiffe's transformer outfit may be used. Gaiffe's transformer outfit, without any interrupter, for x-ray and high-frequency apparatus, is described in detail on page 744. The ordinary alternating electric-light current passes through a primary wire, which surrounds one part of the circumference of a magnet which forms a complete ring. Around another or the same part of the ring is wrapped t he secondary wire. The voltage in the secondary wire is as many times the original 110 volts as its number of turns of wire is times the number of turns in the primary wire. The magnetic ring, with its primary and secondary windings, constitutes a transformer: in this case a step-up transformer, since the voltage is increased by it. The switches and liquid rheostats and condensers are all arranged as for ./-ray work, but the two ventl'il tubes need not be used. Connection is made from the two ./--ray terminal- to the high-frequency apparatus. MEDICAL ELECTRICITY AND KONTCEN HAYS Such an outfit will work continuously for an indefinite length of time and with ab.-olute uniformity. It is the very best for use with an alter- nating current, and mav prove to be so much better than an induction- coil -ind interrupter that, even with a direct current, it will be advantage- ous to use thi- outfit in connection with a motor generator by which the direct current is made to produce an alternating one. The d'Arsonval transformer is one of the :-imple-t and best form- of apparatus for the production of high-frequency cur- rent-. In ihis apparatu- the poles of an ordinary induction-coil, such as an .r-rav coil, are connected with the inner coatings ot two large beydeti jars, and these inner coatings are further connected with tin- two terminal- of an adjustable and enclosed (muffled) spark-gap, or better, a serie- of several short gaps. The outer coalings of the Leyden jars are connected with each other by a solenoid, which is a coil of heavy wire wound in the form of a hollow cylinder. The turns of this wire, about twenty in number, are about \ inch apart, and require no further insulation from each other. Conducting cords also pass to the patient from turns near the ends of the solenoid. One of these cords terminates in an ordinary metal handle, which is usually held by the patient. The other sometimes terminates in an insulated handle held by the operator. This has a metallic socket, into which fit elec- trodes of metal or of glass; t he lat ter are vacuum I ubes of various kinds, or this wire may terminate in the metallic plate of an autocondensation couch, or neither wire may go to the patient, but they may lead to op- po-ite extremities of an aut oconduct ion cage. The poles of the .r-ray coil are widely separate^!; the points of the spark-gap o! the d'Arsonval t ran.-tormer are separated about one-third or one-half inch and a sufficient current is turned on to cause a rapid and uniform succession of sparks aero.-.- the spark-gap. The latter is muffled, enclosed in a glass cylinder or vulcanite box to deaden the tioise. Nitric acid fume- are generated by the passage of these sparks through the nitrogen of the air and a metallic nitrate is deposited upon the interior of the glass, which eventually interfere-; with the -park-gap by short circuit ing and requires to be cleaned out . The pat ient , holding one of the handle- m one hand and a vacuum electrode m the other, \\ill experience- no sensation but that of a gradually developing warmth I he vannim electrode. This is true even wilh a current of 200 to . )i ii i ti ilha mperes pa.- -I ir_: t h rough the pa t len t . 1 he vacuum elect rode become- lighted up bv wave- of violet light pa.-Hiig down inside the ng each other at a rate which seems to be the same as In -parks aero-- the -park-nap. This is ordinarily at the same lerrupter. A hot-wire millianipere'ineter, place-el m -cries patient, -hows the strength o| l he current. If the electrode tacl with the skin, sparks may be -een beginning at nee and pas-ing along tin- out-ide of the glass to the n a product ion of o/o ne from I he -a me -parks. Tin-re r-i mi i ! wi ill tin- pa i lent . lie i- on a .-hunt circuit 1 he fact t hat lie get - any ni rrenl al all i- due t o ii 1 I ie -oli Hold developed bv 1 1 - sell'-iiie Inct loll . itide-cenl lamp hv direct conduction of high-fre- o pi : -on- hoi' I each a mi I allic < !' -cl n n |e from one al t raii-forniei and each bv hi- other hand holds '_' to all elect He lamp -ll-pended bet \\ een them. HIGH-FREQUENCY CURRENTS 545 The lamp may light up brightly and still the persons experience no sen- sation from the current passing through their bodies. The author'* vacuum electrodes, with a vacuum of about , -,/ of an atmosphere, are made with a leading-in wire passing just through the thickness of the glass at the point where the tube has a screw thread. The tube is screwed into a metal socket well up inside of a special handle of hard rubber, which is completely insulated. No current can be received by either the patient or the operator from any part of the handle. The glass electrode is the only bare part, and contact with that is not disagreeable at all, although the current may be sufficient to light up a 16-eandle-power lamp placed in circuit with the patient. Those for the surface of the body are simple tubes with a dome-shaped extremity, while some of those for the mouth, rectum, or vagina have an insulated stem where they enter the cavity and where sparks might occur from the contart being less perfect than full her in where it is sur- rounded by mucous membrane. This insulation is accomplished by having the vacuum tube very small along this portion of its length, and having an air-space between it and an outer tube of glass, which is of uniform caliber with the portions of the electrode above and below it. The waves of light may be seen in the upper and lower and the narrow central portion, but are absent from the outer jacket sur- rounding the latter, and no current is obtained by touching this outer jacket. Other vacuum electrodes are made without any wire, the current being of sufficiently high tension to penetrate glass of any reasonable FiK. 341. Auto thickness. In this case, to obtain a sufficient current the glass should be quite thin and there should be a large area of contact with the metal handle to avoid overheating the glass at that place. Different forms of metal and glass electrodes for various parts of the surface and for 1 he different orifices of the body are made, and will be considered in detail in the section upon the Therapeutic Application of High-fre- quency Currents (page 1 f>">S). The autocondensation couch consists of a sheet of metal or a flat mass of wires connected with one pole of the d'Arsonval trans- former, on top of which is a thick insulatiim mattress upon which the patient lies. The handle from the other pole of the d'Arsonval trans- iormer is held in the patient's hand, and when the apparatus is in opera- tion a cm-rent of 100 to 100 or SOO milliamperes is indicated by the meter which is in circuit with the patient. The patient becoming charged with 546 MEDICAL ELECTRICITY AND RONTGEN RAYS one kind of electricity and the metal plate with electricity of the oppo- site sign, and the insulating mattress intervening, form a complete con- denser on the same principle as a Leyden jar. The patient corresponds to the external metallic coating or armature of the Leyden jar, and each time the patient and the metal sheet become overcharged and a discharge takes place across the muffled spark-gap of the d'Arsonval apparatus the patient undergoes a very great number of electric oscillat ions. In another couch which the author has used the principle is rather that of atitoconduct ion. The couch consists in some cases of a wire mattress in two parts, very heavily insulated, each end being connected with one of the poles of the d 'A rsoiival. High-frequency currents are produced in the patient by induction from the wire couch without any metallic connection reaching the patient. Another couch consists of indurated fiber an eighth of an inch thick, up"ii the back of \vhich is a sheet of ./'-ray metal, and this covered again with a light insulating cloth. This is made in two section.-, hinged together with (juite a wide insulated separation, the wire from one pole of the d'Arsonval passes to one metal sheet, and the wire from the other pule to the other metal sheet. A convenient way to use it is to place it on an ordinary chair so that one part forms the seat and another the back. There should be no metallic parts to the chair except the ordinary nails and tack.-. Before the patient is seated upon this the current shown by a millianiperenieter in circuit with the couch may be 15d milliamperes. and the moment the patient sits down it may increase to over 100 milliamperes. This is without any sensation. Through the patient'.- back lie receives an induced charge from one metal sheet, and through the lower part of the body and the thighs he receives an induced charge of the opposite sign from the other metal -heet. Tim-, aii extremely rapid series of condenser discharges is produced through the patient's body. If a stronger current is turned '\:. 5oi i or di ii i milliamperes. considerable brush discharge parses to the patient through the indurated liber. While this is not disagreeable mf il for a -hort time, it is better to avoid it in general. \\iih the aiitocoiidensat ion couch used bv the author the current in;t\ be between 1 00 and 500 milliamperes when the patient is seated poii .' and ihu- bv a conductor effect facilitate- the discharge. And nt leaves the couch the current \\;l] be seen to diminish 'V I'll) nuiliamperes. It will be remembered that if two l.evden om the prime conductors ot a static machine and a ds the outer lavej-.- of the jars, treinendouslv powerful pa.-- bet ween the pole- ot 1 lie coll. These are a t housaild the discharge which take- place when ihe rod i.- dis- tlie outer laver- of th 1 ' Leyden jars. The wonderful : takes place between the pole.- of tin- .-tat ic machine place i- accompanied and. one can almost say. pro- i ' discharge \\hich passe.- through the ouch in question ihe lead plate- to \\ |iiencv coil correspond to ihe inn in the experiment with the stati -pond- to the outer layers of the two 'hi'Tii. The difference between th HIGH-FREQUENCY CURRENTS 547 couch, with and without the patient, shows roughly the amount of electricity induced in and discharging through the patient. The autoconduction cage is a hollow cylinder formed by a coil of wire the turns of which are widely separated. The cage may he placed vertically, and the patient stand or sit inside of it, or it may he horizon- tal and surround a table top on which the patient lies. Its two extremi- ties are connected with the two poles of the d'Arsonval transformer, and when in operation high-frequency currents are produced in the patient without his being in metallic connection with any part of the apparatus. Measurement of High-frequency Currents in Autoconduction. The niost practical measurement of the strength of the current induced in the interior of the autoconduction cage is in (Jausses, as described by Doumer. and depends upon the amount of current induced in a loop of wire placed inside the autoconduction cage and parallel with its turns. The currents are alternating, and the amperemeter is usually a thermic or hot-wire instrument. The graduations may be directly in (iausses. The frcf/itenci/ of the oscillations in high-frequency currents may be measured by Feme's ondomctcr. This has a certain length of wire, which may be placed parallel with and close to the wire through which the oscillatory current is passing. The wire mentioned forms part of a circuit which also contains a self-induction, a condenser of adjustable capacity, and a hot-win 1 milliamperemeter. The capacity of the con- denser in the ondometer is regulated so thai the maximum current is registered, indicating oscillations synchronous with those in the circuit to be tested. The condenser is graduated in figures representing the number of oscillations per second. This is between 300, 000 and 1)00,000 for most high-frequency work. Kficd* of Autoconduction and Autocondenxation. With both the aut (condensation couch and the autoconduction cage the patient does not feel any electricity, but its presence may be proved by drawing -park- from any part of his body and even a slight violet brush dis- charge may take place between the patient'- two hands if one finger of each are brought lightly together. A variety of experiments may be performed with incandescent lamps or telephones to demonstrate the presence of electricity on every portion of the pal lent '.- surface. To liu'ht an incandescent lumj) by autoconduction it is only necessary to connect it by a loop of wire held in-ide a solenoid traversed by high- frequency currents. A vacuum tube approached to the solenoid lights up. Any body inside a solenoid is itself traversed by high-frequency current -. Piffard's Hyperstatic Transformer Fig. 342).- This apparatus is devised to obtain high-frequency currents from the static machine. Two medium-sized I.evden jars have their inner coatmir- connected wit h t lie t wo prune conductors of the static machine. The sj iark-u;a | > i- obtained by separating the poles of the static machine about an inch. The outer layers of the Ley den jars are connected with the extremities of a small solenoid, at the end- of \vhich are binding-posts. With the plates revolving at the rate of :>()() or .'!">0 tunes a minute there is an etlluve to be felt from both binding-posts, ihat corresponding to the positive poie of the static machine beiim' the stronger. For mild applications a vacuum elect rode i- con nee ted with only one 1 1 he positive i pole of the hyperstatic transformer. For a more active effect the MEDICAL ELECTRICITY AM) RONTGEN RAYS patient holds a metal electrode connected with one pole while a vacuum or a metal electrode from the other pole is applied to the region to be treated. Pif'fard's own belief is that the hyperstatic current is chiefly valuable for a local effect, as in chronic ec/ema, and that it cannot take the place of the d'Arsonval current, with its vastly urea tor amperage, for the production of constitutional effects. The static machines usu- ally found in Europe scarcely amount to more than laboratory toys. It i- only the large American machines with eight or more pairs of plates, 30 inches or more in diameter, that are suitable for this therapeutic application. THE OUDIN RESONATOR \\c come now to another type of high-frequency apparatus in which a conden-er discharge is passed through one or more turn- of an as- ccnding -piral of which the upper end is free. The -elf-induction in the -piral increases toward its extremity, where the tension is such that the wire give.- off an efrluve or 'brush discharge of -everal inches into the emptv air and a much more powerful one if -ome conductor like the human body apnroache- it. Quite a u-ual model i- shown in Fig. 343. The pule- of the induction-coil, or static machine, or transformer, are connected to the inner armatures of two Leyden ja>'- 'the condensers!, and t he-e -aine inner armature- are connected with a muffled spark- uap. The outer armature.- of the two Leyden jars are connected I >\ a -olenoid ju-t a- in the d'Arsonval Iran-former, but in addition a wire pa--e- Mom one end of the -olenoid to the lower extremity of l he vertical coil the < hidin resonator proper' ;1 iid another wire pa--e- Mom an adju-table contact, u-ually near the middle of the et 1 1 .id. to aiiot her adjustable contact with t he < hid in resonator. . . li! t h of t he distance from its lower pole. The adjust- ment between i hi amount of -elf-induct ion in the.-e two coils produces harmoit\ ectric oscillation-, and it i- trom hi- resonance that t he app.-i : : ' . eri\-i- it- name. In order that tin- -hall work we'll it i- nece--ar\ to -e the proper turn in the -piral to which the second HIGH-FREQUENCY CURRENTS 549 Leyden jar shall he connected. This is done by starting the Ruhmkorff coil and t hen making a connection \vn h t he different 1 urns successively. Another t'onn of resonator used by the author is made in the shape of a flat spiral, the outer end of which is soldered to the next turn of the wire and is also connected with one end of the small solenoid. The ot her end of the small solenoid may lie connected with either the second, third, or fourth turn of the spiral. The center or inner end of the flat spiral is free, and corresponds exactly with the upper free end of the upright i'ig. 3415. The Oudin resonator and d'Arsonvul hiirh-frrqupnoy apparatus. cylinder type of Oudin. In my model the spiral is 30 inches in diam- eter, and there are binding-posts at different parts to enable various strengths of discharge 1 to be used. The eflluve from the middle of the spiral is very powerful. The coil is large and heavily insulated and the turns of the spiral are about 1 inch apart. The Oudin resonator is intended principally for unipolar applications, either as an efHuve from pointed electrodes held at a distance from the MEDICAL ELECTRICITY AND RONTGEN RAYS surface of the body, oi 1 by din-el application from vacuum or other electrodes applied to the skin or mucous membranes. It requires at least a I'J-inch induction-coil to actuate an Oudin resonator to the best advantage. Bipolar applications with the Oudin resonator may be made by the etthive from 1 \vo i-esonatoi-s applied, for instance, to the front and back of the chest, or the metal plate of an autooondensation couch may bo connected \\iih one resonator and an ehMuve from another resonator be applied over the patient. When two resonators are used the lower |e of ' a en :- at t ached to the opposite end.- of t he small :-olenoid. When autocondensat ion couch the full ' - t he outer armat ure> ol t he I .ev den jars are connect ed hi Oudin resonator, one \\iih ilie lower pole and the In r. The-e lower tin 1 !:- oi i he resonator produce !:''' ;,, the -mall solenoid and enable tin- to be di.-pensed TESLA HIGH FREQUENCY CTKRhNT 'h'am '!>!- from tin i Ill-volt dii'eci i-iirrent it i.- neces- i rat u> a> de-cnbi-d tor t lii- d A r.-onval current . and ddi'ioii. a !IM\VII \'. >*'<. p. oil. and insulating tube is placed i he -mall solenoid of d'.\ ix ii va 1 . and i hen a winding ed either in-ide of the tube, if i he tube is placed HIGH-FREQUENCY CURRENTS 551 inside of the small solenoid, or outside of the tube if the tube is placed over t lie small solenoid. As described by Tesla, them is in addition to this insulating tube a liquid insulator in the form of oil. but as the apparatus is ordinarily constructed for medical purposes the oil insulation is not, required. From the terminals (' the Tesla high-frequency cm-rent will be obi allied. The Tesla transformer is a source of extremely high potential discharges at a rapid rate, and can be used to excite an Oudin resonator for medical purposes, but. is more suitable for exciting Hertzian waves in wireless telegraphy. The transmitter for the latter consists essen- tially of a Tesla transformer and an Oudin resonator, whose upper ter- minal is carried to the top of the mast of a ship or of a high flag-pole if on shore. The Tesla transformer consists first of a primary coil, through which (lows a rapidly interrupted current of high voltage from an induction-coil or from a step-up transformer; this primary coil is surrounded by a secondary coil, consisting of a large number of turns of very fine wire, and the originally high tension is enormously multiplied. Other essential parts of the Tesla transformer are the condenser and an adjustable spark-gap between the extremities of the primary coil. The condenser and spark-gap serve the same purpose here as in the d'Arsonval transformer to be described later. Both the primary and the secondary coil and the condenser are immersed in oil to prevent sparking from one coil to the other. The terminal pole.- of the '1 esla transformer are wide apart, and the discharge from them is of alto- get her ext raon linary power. To excite an < hid in resonator one terminal of the Tesla t ransformer is grounded and the oi her terminal is connected wit h t he Oudin resonator at the height found to produce the best results. 1 )'. Henry ' !. Piffard of this city modified the original Tesla apparatus so as to make it applicable to any static machine, and in order to differen- tiate it from an apparatus operated by a coil he called it the hyperstatic trail-former. At the present time we have practically only two forms of high-frequency currents in use in medicine. These are t he d ' Arson val high-frequency current and the Tesla or Oudin high-frequency current. The therapeutic applications of the Tesla and Oudin currents are identical, the other physical characters are also identical, the only difference being in the mechanic construction of the apparatus itself. In a general way the therapeutic applications of the two forms of high-frequency currents are as follows: The d'Arsonval. which is a low-voltage high- frequency current of comparatively high amperage, is used for its con- stitutional action. The Tesla and Oudin resonator current s are currents ot hiirh irequency. high voltage, and comparatively low amperage. They are used mostly for their local and reflex effects. Violet-ray Treatment. This is a term which has been used very carelessly, as there is reallv no such treatment. It has usually been applied when a vacuum electrode is used, without regard to whether the current was a high-frequency one or simply a high-voltage one. < 'it her beinu' sufficient to cause t he violet color to appear in t he elect rode. Ultraviolet-ray Treatment. This is another term which has been very carelessly used, it bein used. As the ultraviolet rav will not penetrate the thinnest piece of mica or celluloid, the results which have been obtained when using the vacuum electrode are due to the form of current applied, and not so much to the ultraviolet rays, which are Liiven of)' from the sparks outside ''- MEDICAL ELECTRICITY AND RONTdEN HAYS <>f the electrode. AYhenever a spark takes place there is a generation of ultraviolet rays. but these rays are invisii)le to the human eye. All hijrh-fivquency current- are om ! -n-ers l-'i^c. '> 17 . Viiri ill - !' |i'r-irnliinl(iL r i", l-'t-hruarv, I'.'iiH. HIGH-FREQUENCY CUHKENTS A utoconduction Cage. This form of high-frequency application is the typical d'Arsonvali/ation. The spark-gap is between the internal armatures of the condensers (Fig. 348), and the patient sits or stands 'e a large solenoid or coil of wire, which is connected with the outer t ures. The patient is not in contact will) any part of the a p pa rat us. i utoconduction hi/ Douhte (1 u ill< //// not Spiral*. (Juilleminot 's technic places the two spirals so that they are parallel and in the same direction (Fig. 349). Starting from the external armature of one condenser the discharge passes to the external extremity of one (iuillemmot spiral, then through fifteen turns of the latter, then through a conducting I'ii:. .'vlN.- Autoponduction from d'Arson- val's larjrc solenoid. Tip. 34!). Gui cord to the outer extremity of the othei 1 spiral, then through fifteen turns of the latter, and then through a conducting cord to the external armature of the other Leyden jar. It is important that the two spirals should be turned in the same direction. They are placed with their Hat surfaces parallel with each other and 24 inches apart. With a powerful induction-coil or transformer and good condensers and spark- irap the space between the two parallel spirals becomes a very strong electromagnetic field. A single turn of wire, hanging freely in this space and parallel with the external turns of the spirals, will be traversed by a current which will light up a series of 12- or 20-volt incandescent lamps. There is no spark or effiuve effect from the inner extremity of each spiral with the connections made in this manner. For treatment the patient's body should be so placed between the two spirals that the long axis of the body is parallel with the external turns of both spirals. The simplest way i- tor the patient to sit with a spiral at either side of him and with his legs raised by some kind of a foot -rest . Aulni'nnduction !>// Guillcminot S/iirn!* in A/'tii'ntl Hypertension. The treatments last twenty or thirty minutes, and in !"> cases reported by ( lUillemuiot l 1 he result of a course of t real im-nt s was to reduce 1 he blood-pressure from about 21 cm. of mercury to about 17 cm. Fifteen or twenty treatments sulliced to produce a permanent effect, and after the first six treatments any general symptoms, such as vertigo, debility, dyspnea, chilly feeling.-, were greatly relieved. . 1 ulorondcnxation . --- - \\ ires from two different turns of the small solenoid uniting the two outer armature- pass, one to an electrode held 1 Arch. ii 'dec! riritc mcd., SrpU'iiiber Id, I'.MIti. 004 MEDICAL ELECTRICITY AND RONTGEN RAYS by the patient and the other to a large sheet of metal upon which the patient lies, but from which he is separated by an insulating mattress (Fiji. o."iO>. riwfoww tolatietif Fin. ;v>0. - - Autix'uiKlcnsation. Fig. .'),"!. _'.- HiiMihir rcsoiiatur (O'l arrcl :n d 1 iv inductoresoiianee induces ;i ven I her urnier extremity of the solenoid < HIGH-FREQUENCY CURRENTS 55") A Bipolar Omli'n Resonator. The wires from the external arrnaturo.s of the condensers are connected with two of the turns near the middle of the helix, and a high-frequency and high-tension discharge lakes place from both extremities of the helix (Tigs. 352 and 353). (iiiiUcniinot'x S/>irold for high-frequency and /-ray work I-'ii:. o.V.t i- usually a Tesla outfit. Another portable hi-h-fre([uency coil (Fig. 3o()^ is of such a si/(> and / that n inav hanfr from anv electric-light socket. It rdinary < Direct discharge, metallic < Indirect dis- i electrodes. ( charge. ' Glass vacu- f I:)ir( .' ( ' r '^charge. 4 Indirect dis- um tubes. , i charge. Electrode in (Ordinary metallic electrodes. motion. \ Glass vacuum electrodes. With Pii'fard transresonator. [Producing the high-frequency cautery arc. [Special glass vacuum electrodes applied to mucous membranes. Without resonator. f Ordinary metal exciters. I Containing air. One electrode on the Sparks by ! , f , skin and the other | means of: ] Glass tubes: Containing salt solu- T(>sla yacuum tubes. Stat ionarv efHuvi MVIII ant uei i over exciter opera- ' ting at a distance. [Rhythmical mobile eflluve. One electrode on the skin, the other discharging sparks against a metal also in contact with the skin (mediate discharge analogous to static wave currents). Both electrodes at a distance from the skin (double effluve). One metallic electrode applied to the skin, the other a glass vacuum electrode also applied to the skin. Special glass vacuum electrodes applied directly to the surface. One electrode from the Tesla-Thomson coil is applied directly to the skin, while another applies sparks to a metal ball held near another part of the skin (indirect sparks i. One electrode represented by PitVard'.- t ransre>onator is applied to the skin, while the electrode from the other terminal of PifTard's hyperstatic transformer is applied to another part of the skin. ( With insulated ( With interior metal conductor. handles. I \Yithout interior metal conductor. < Insulated throughout their extent, except the active part for the urethra, rectum, vagina, mouth, etc. Decrees of vacuum : 1 /.")()() atmosphere -reel vacuum. 1/10,000 atmosphere white vacuum. 1/100, 000 atmosphere. MEDICAL ELECTRICITY AND RONTGEN KAYS METHODS OF AITLYIXC, HIGH-FREQUENCY (TKKKNTS (Continued). Mi\(>4."">j The author'- handle ' Fisz;. .'> (>:!! i- made of hard ruhher. insulatin; all the metallic portion- from accidental contact with the patient, no matter what part of the handle may t nidi him. Hie conductin ;', -.'d iron, a continuous stream ot whit' spark.-. Such a burn in :: i-in-j pain for only a few second- : it leaves a dry port ion which come- oh like a -cab. leaviim a perfectly Application of High-frequency Current Vacuum Electrodes Through the Clothing. Contrary to the condition- obtaining when ' '.'. iVe of 1< i'.'. frequency Upon a current of 1 1 in 1 1 lVe(|Uency. lo t ho-e nf Snt' the author's completely in-u- MEDICAL KLKc riUllTV AND ItUNTCJKN UAYS ralvanic or faradic applications arc made, high-frequency current and other u'la.-s vacuum fleet rode applications are not nuiterially affected I iy t he presence of a single very t hin layer of silk, cotton, linen, or woolen clothing. Increasim: the thickness of the material markedly changes the charade!' of the discharge. .\ thicker layer of material, such as the u nderwear and t rou.-er.-. changes the character of t he a pj >\\ cat ion entirely. The adjustment of apparatus which will .u'ive a mild discharge without spark effect, hut with the hull) filled with brilliant light when the bulb is directly in contact with the skin, shows practically no luminosity when applied through thick clothes. Xo beneficial discharge occurs through the clothes in this case. To obtain luminosity and a therapeu- tic effect it is necessary to adjust the strength of the primary current, the length of the -park-gap, and the other factors so as to produce a stronger discharge. There is a great deal more sensation because of the -park effect, due to the distance between the electrode and the surface of body and because of the stronger currents employed. A tube that is brilliantly illuminated produces a .-harp burning sensation if applied through the trousers and held at one place for a short time. It >hould usually be kept in constant motion, and then produces no undesirable effect, the skin not being reddened unless the current is applied to a small region for an appreciable length of time. The author ha- never seen any injury to the clothing. The effects of the application of a vacuum electrode through the itiimie-t underclothing are practically the same as if applied to the .-kin. There is the advantage of modest}' in some cases, and no powder i- required to enable the electrode to glide readily over the surface. The therapeutic uses are the same as those of the direct application to the skin. The effects of an application through thick clothing are actively counterirritanl and rubefacienl if the electrode is kept in one place for an appreciable length of time and if the current is quite a strong one. They are revulsive without rubefaction if the current is less powerful and the electrode is kept in constant motion. The therapeutic uses an- found in cases of chronic articular or muscular or nerve lesions where a powerful counterirritanl effect is desired, and in some cases of iicura-1 henia, applied alon.i; the spine. The general indications for hi^h-tensioii hiirh-t requency currents are met by this application in cases where a very marked local effect is permissible. Physiologic Effects of High-frequency Sparks and Effluves. The etlluve I ron i a re.-onat or applied from points 4 to 10 inches from t he sur- ke a fine cool or hike-warm bree/e. and t his produces analgesia -edation. From a nearer point there is a prickling, contraction of cutaneous muscular fibers, redness, and arterial hyperemia. Nearer there are powerful muscular contract ions, both al the active efH live rode and al-o at the indifferent contact electrode from the other of the re-oiiator, but there i.- practically no heat generated in the Actual -park- applied in one place stimulate t he cutaneous mus- er- ) u ise fle-h i and vasoconstrictors. After paleness, lasting t'> one minute, an inten-e cry t hem a develops. Prolonged appli- ed by vasodilatation. edema, blistering, diapedesis of red longer hm'h-t elision >park.- cause contraction of deep-seated Electrolytic Effect of High-frequency Sparks. I Fmh-frequency cur- HIGH-FREQUENCY CURRENTS 5()1 rents in general do not affect a solution of iodid of potash, but high- frcquency sparks produce tiny blue points upon the surface. Xagel- schniidt does not suppose that there is any important electrolytic effect upon the tissues from either the direct or the indirect high-frequency spark. Fulguration, or Keating Hart's Method of High-frequency Sparks for Cancer. 1 This method consists in the application of Ion;; and powerful sparks for the dest met ion of morbid tissue. The apparat us" may be any of the resonators giving high-frequency currents, and inav be either monopolar or bipolar, the latter being preferable. The patient holds a metallic electrode connected wit h one pole of the resonator, while the spark elect rod* 1 is brought near the diseased area. This electrode has an insulating sleeve, by which the length of the spark is exactlv regulated, and a current of air or CO., is forced through it to keep the temperature from becoming too high. The strongest possible discharges are used. In the case of a small ulcerated epithelioma the application is divided into four different steps. At first several sparks are applied, producing blanching of the tissues and a marked degree of anesthesia, then more powerful sparks are applied, softening the tissues; third, the tissues treated by the sparks are curretted and enucleated; fourth, the same powerful sparks are applied at the bottom of the wound to elimi- nate any traces of neoplasm. Larger tumors, especially those in which ulceration has not taken place, require the surgical procedure first, followed by the high-fre- quency sparks over the floor of the wound. The treatment requires a general anesthetic, and in some cases it is preferable to destroy different parts of a large tumor at a number of different sittings. A typical operation by this method consists in an excision of a can- cerous breast and axillary glands, under general anesthesia, of course, and then the application of these long, loud sparks to the entire raw surface, except the under surface of the skin flaps, which would certainly become necrotic if subjected to this treatment. As each spark strikes the exposed muscle a bunch of muscular fibers may be seen to contract violently. De Keating Hart continues to apply these sparks for a number of minutes, until the entire surface 1 changes from a raw red to a dry. brownish, cooked appearance. Ample provision is made for drainage when the wound is closed. The consequence is a tremendous oo/ing of serum and a wound affording a fruitful field for infection, against which the greatest precautions should be taken. The theory is that the fulguration has a tendency to prevent recurrence by its effect upon the remaining tissues. Of course it cannot prevent .recurrences in the skin or along the cicatricial line, because it cannot be applied there. Having seen the method applied by the brilliant originator, and con>iderinir the results reported, the author feel.- that he cannot recom- mend this method for cases of this character. The claim is made that recurrence-; are very much less prevalent after this method than after simple surgical excision, and that the cicatrices are as good cosmetically a> those following radiotherapy. High-frequency sparks seem to have a selective effect upon morbid ctilo. Auiiust 10. I'.tOT. 502 MKDIfAL KLi;( TKKITY AND RONTGEN KAYS tissue, and the line of cleavage between the tumor and the surrounding Ik'sh becomes more marked. The enueleation is easier. The sumo method has been applied lor local tuberculosis, lupus of the skin and of the nose, and has even been found useful in certain cases oi chronic .r-rav dermal it i.-. Many different electrothorapeutists employed hitrh-frequency sparks before the publication of Keating Hart'.- method. The originality latter seems to lie in the combination ot surti'erv and electricity. ! he auihor's electrode ( Fi^. ;]()()) tor applvint: hitrh-frequency for thej'i 1 de.-tnict ive effect \vas described at a meeting of the 'an [.!<<' ro' h'-rapeut ic Association in I'll).", and provides a :.' in- : . .. ' : the -tren^th of -parks irom zero up to their maxi- :. .' !' :. '. '['hi conduct inn-cord from the re.-onator is attached to the portion of t hi electrode whii'h i- to be applied to the patient. '1 hi- portion i- -eparaieh electrode is connected with the upper extremity of the same resonator. An improvement consists m placing the patient upon an insulated platform. The appli- cations are made every two or three day-. They last ten minutes, and an 1 followed by a series of sparks lasting ten or fifteen seconds. The Croirn cfflni-cr (Tig. 'l\'->7 ' has a range of usefulness similar to t hat of t he st at ic crown. The Effect of Condenser Electrodes. The>e electrodes consist of a metallic or other good conductor, covered by glass or hard rubber, 1 Le Radium, September !"), 190,"). p. :'>(Y2. o()4 MKDK'AL KLKCTKU'lTY AND KONTGEN HAYS acting as an insulating dielectric between the body and the conductor. A ii'hiss tube, shaped like a vacuum electrode and tilled with salt solu- tion, makes an excellent condenser electrode to be rubbed over the general -urface or for introduction in the rectum. Such an electrode is applied to the ( D- f surface and is con- nected with one pole of the d 'Arson- val apparatus, while the pat ient holds a metallic electrode connected with the other pole. The effect is the same as when a glass vacuum elec- trode is used with the same kind of current. In the particular case de- scribed, and if the apparatus is ad- justed for great amperage and low voltage, there will be little or no spark effect, and the local effect will be ant iphlegmasic and seda- tive, while the constitutional effect will be to lower the blood-pressure if it is unnaturally high. There will be the same other less-marked effects that are obtained when a glass vacuum electrode is used.. In no case does the salt solution in the condenser become luminous, and with the current regulated for a distinctly d'Arsonval effect there is only a little violet brush discharge where an imperfect con- tact is made wit h t he skin. A salt solution condenser elec- trode, with a hiiz'her voltage dis- charge, gives the same shower of spark- as the vacuum electrode. but much stronger with the same conditions in the rest of the ap- parat us. This strong application pro- duce- a powerful revulsive effect, inakim: it wonderfully effective in some cases o| neuritis and mvositis. -oluHon condenser electrode is the mo.- 1 perfect means of al applications for obtaining the different effect.- of the dis- HT trom a -tatic machine, ;, ..'e from a high-frequency apparatu.- of either the d'Ar- inva! oj t he < >udin Type. > ilideli-'T eject rode.- of met al \\ i' h a covering oi ha rd rubber produce - -imilai to tho-e from .-alt Milution :Ja-- condenser electrodes, ut are u-ualb not intended to be rubbed over the -urface of the hodv, HIGH-FREQUENCY (THKEXTS but rather for introduction into the urethra or nose or for applications t;> the conjunctiva. Condenser Electrodes of Large Size. This is exactly what the autocondensation couch or pad amounts to. Thev are especially in- tended for use with the d 'Arsonval or comparatively low-tension high- frequency currents, and except in the case of sciatica are generallv used for the constitutional effects described in the section on Autocon- densation. OTHER APPLICATIONS WITH EFFECTS RESEMBLING THOSE OF HIGH- FREQUENCY CURRENTS Glass Vacuum Electrode Connected with One Pole of a Tesla Transformer, Known also as a High-frequency Coil. An easily portable outfit no larger than a handbag has been introduced in America ' v the ISeeley .r-ray apparatus and others), which consists of a complete Tesla apparatus. This requires only to be connected with an electric- light socket to be ready for bipolar use for exciting an J'-ray bulb, or one pole only maybe used to excite- a vacuum electrode. The last application is the subject of the present paragraph. It has the same rather sharp spark effect which characterizes the similar use of an induction-coil, and the patient is liable to jump if any metallic object or another person touches him. It is, therefore, a less agreeable application than the one which employs a d 'Arsonval or an ( )udin apparatus to excite the vacuum electrode. A shower of sparks from it would be disagreeable. The therapeutic effects are similar to those from vacuum electrodes con- nected with the Oudin resonator. There is no muscular contraction and scarcely any sensation but that of warmth. There is a stimula- tion of metabolism and a tendency to raise arterial tension when it is abnormally low. It has analgesic properties. Glass Vacuum Electrodes and the Static Machine. The elec- trodes should have leading-ill wires. Their effect when connected with a high-frequency apparatus, either d 'Arsonval or Oudin. actuated by a static machine, is about the same as when the high-frequency apparatus is actuated by an induc- tion-coil. Their effect when connected with one pole of the static machine without Leyden jars is somewhat different. The discharging rods of the static machine should be about .1 inch apart. A series of shocks are felt when the electrode is held in the hand. It is as if slight muscular contractions were being caused, producing sensations m the different tendons in the wrist. If the electrode is hghtlv applied over the sensorv nerves in the proximal portions of the lingers, a slight tingling sensation is felt at the distribution of these nerves. Rather sharp but very small sparks are felt when the elec- trode is held at a small (list a nee from t he surface. A greater separat ion of the conduct ing-rods produces more marked sensations of muscular contraction, which may extend up as far as the elbow. There is. how- ever, no actual movement of the arm and no rigidity. The person is fully charged during this application, and any one touching his oilier hand, for instance, receives a sharp spark, which causes the hand to be 'drawn away. The therapeutic effect of the application is almost exactly the same as that of the Morion wave current. Glass Vacuum Electrodes Connected with a Static Machine and Leyden Jar. These give the same sensations as the application ')()( MKDICAL ELECTRICITY AND UoXTCiKN HAYS last described, and the same physiologic and therapeutic effects as the static induced current. The external armature of the Leyden jar con- nected with one pole of the static machine is grounded, while the glass vacuum electrode is connected with the external armature ol the other Leyden jar. These two methods of using the vacuum electrodes with a static machine are convenient means of local application of static electricity. Their effects are not due to the light in the tube, but to the nature of the current transmitted through the partial vacuum. The patient need not be insulated. A Glass Vacuum Electrode Connected with One Pole of an Induction-coil. A coil suitable for .r-ray purposes may be used for this application. The vacuum electrode does not show much light until it is brought near the patient. Then quite sharp sparks pass to the surface, so that it is necessary to apply the electrode quickly, or in some cases, as in the rectum, to apply it before turning on the current. As the electrode is passed over the surface it is quite essential to con- stantly maintain a good contact with the skin, talcum powder enabling the electrode to glide smoothly over the surface. Kvery part of the patient i- charged with electricity of such a kind that imperfect contact with any metallic object or another person will give rise to disagreeable shocks. A child sitting on its mother's lap while this application is beinir made usually cries most of the time because of the succession of shocks received from the mother. The indue! ion-coil should be regu- lated to produce about a 2\-inch spark. The spintremeter should be set at ;! inches, so that the patient will be protected against the pos- sible occurrence of an excessive discharge. The application causes no muscular contraction and no sensation except that of warmth when the electrode is in perfect contact and a moderate current is used. Such an electrode held m ihe hand while an excessive current is applied, the lull power o| an induction-coil, produce.- no muscular contraction in the sen-e lit not being able to let go ot the electrode or to move the arm in any direction. There are, however, the slight tingling sensations in the tendons about the wrist which nio-t strong electric applications pro- duce. There i- nothing to be gained by making such an excessively st romr application, but it (JIM- not affect the patient injuriously if done accji li-nt 1 v or for experiment . lii" effect ,if a -_dass vacuum electrode connected directly with : an ./'-ray induction-coil i- to produce a local counterirritant effect wi'hout the necessity for redden inn the skin, and a general effect in 'h'- ' on nf increasing metabolism and stimulating the sympa- t ii>- r ic nerves and glandular activity. I" i- an excellent application for facial neuralgia, and mild cases 'not tie douloureuxi -how improvement after the first treatment. I'aral; ',< d in i-cle- sometimes regain then- si/.e and tune in consequence at ion. a- in cases of infantile paralysis t real ed bv the author. I' ' . ' be preferred to the Otidin or d'Arsonva] currents 'mini electrodes, and never for the application of a stream ot spark-, In ' MI e i hey are of a very disagreeable character. Hertzian Waves. These are electromagnetic waves propagated to en ' ci - . and made u-e of in -ending wireless messages for a distance oi ovei a thou-aiid miles. They a re liberated bv the dis- charge oi ci imi-riii] and its condenser, and their commercial use i- based upon the fact tha' thev greatly lessen the resistance at an HIGH-FREQUENCY CURRENTS 567 imperfect contact, and thereby act at each impulse to turn on a stronger current from the local battery which operates the telegraph receiving inst rumen! . These electromagnetic waves are generated in abundance by r-ray and high-frequency apparatus, and there is no doubt that they produce therapeutic effects. The Marconi (///v/f.s.s telegraphy .vending and rcct-iriny xtation is shown in Fig. 368. *S. Switch to connect antenna with cither sending or re- ceiving outfit. In sending, every stroke of the interrupter charges \V with a high electric pressure, which is relieved by the spark making Fiji- 308.- Diagram of Marconi wireless telegraphy (Houston.) a temporary path to the earth. Not only this but more charge rushes out of \\ than was put into it, and then electricity surges back again from the earth into \V. A series of decreasing oscillations take place, like a bent spring coming to rest. Several million per second pass through wire and spark-gap. The visible sparks are twenty or thirty a second. Hertzian waves are set up, but recent work indicates that they do not transmit the message. Probably the currents rushing into and out of the earth tend to charge and discharge the earth itself and start radiating waves along the earth's surface. Receiving, the switch is turned t he ot her wav. ('. coherer, two silver plugs with a pinch of metallic filings, tube exhausted and sealed to prevent oxidation. IV affects a telegraph relay R only when resistance in (' has been reduced by message. IV 1 is connected with the relay and a tape-printing telegraph receiving instrument /'. Y\ aves in the earth encounter vertical wire, ascend it and influence 1 coherer, causing its resistance to drop. A buzzer is striking the coherer all the time, and causes the resist- ance to become great again as soon as the influence ceases. Marconi, as early as September, I'.UO. sent wireless messages from Clifden, Ireland, to Huenos Aires. Argentina, a distance of (1700 miles. ~>''>S MKDICAI. KI.Kt TKKITY AND KoNToKN KAYS THE PHYSIOLOGIC EFFECTS OF HIGH-FREQUENCY CURRENTS Certain effects arc common to all the different methods <>t applica- tion, and these are chieflv those of increased metabolism. Other effects depend upon the mode of application and are chiefly vasomotor. Applications in which currents are induced in the human hodv have a general sedative effect upon the vasomotor system and reduce blood-pressure, while those application.- which act more like static elect rich v. by sparks or eifluve, have a stimulant effect upon tin- local circulation, and an effect upon the blood-pressure which probably sliii'htly elevates it in health and tends to bring it to the normal when it is unnaturally low from disease. Local Effects. --If a metallic electrode is in good contact with the -kin or mucous membrane and the high-frequency current is ot moderate si remit h -/. i .. b")0 milliamperes or less --no sensation is produced until a sense of warmth gradually develops. This may change gradually to de- cided heat if the electrode remains in one place. With a greater strength of current, up to 100, ")()(), or SOO milliamperes. metallic electrodes -till give no other sensation than that of heat. If there were an im- perfect contact, however, brilliant white sparks would pass from the electrode to the surface of the body, and this would produce a sense of pain and a reflex muscular contraction, drawing the affected part away from the electrode. With vacuum electrodes in good contact with the -kin there is a little sensation of stimulation besides that of simple warmth. This is due to the very small sparks which form an invisible part of the discharge, even with a moderate current of 100 milliam- peres. and with a heavy current of iMO milliamperes or more the outside of the bulb is covered with -park.- passing to the surface of the body. In this case there is a sensation as of little .-harp points striking the surface. The high-tension effluve produces a sensation a- of a warm bree/e. and if the effluve is brought too near the surface rather severe .-parks leap to the skin and cause the usual sensation produced by an electric spark, but do not cause muscular contractions. The vacuum electrodes, held at a little distance from the .-km, give rise to a shower of -parks \vhich give only a sensation of warmth with very weak currents, but with moderately heavy currents the sparks are severe and painful, and if applied for any length of time in one place will cause blistering or necrosis. Klectrodes ot copper wire covered with hard rubber sometimes take the place of vacuum electrodes inside 'he nose and elsewhere. Thev LMVC rise to a shower < if very fine sparks. and produci at first a -liidit sense of irritation. ( 'ondenser electrodes . a -.'.I!'- -urrounded bv oil produce more or les.- sparking, and this - "'In ; hi'._'h-t I'ei jiiency applications in the absence of muscular con ' ft'ect upon the skin varies according to the strength of >pli'-a T ioi There may not be an v noi ice able efj'i ( r Effect of Local Iligfi-fre/jinncu Application*.- Usually there is very little sensation and no muscular contraction. "U here il is desirable to produce muscular contractions vibratory currents may be applied by connecting the vacuum elect rode- with one pule of the 570 MF.DK AL KLKCTHKITY AM) KONTCKN HAYS electrode is passed rapidly over the abdominal wall, and if the current is fairly strong a very pretty play of muscular contractions is produced. These are entirely painless. With this application the patient has a high-potential charge, and will receive rather a disagreeable spark if another person or anv good conductor touches him. The vacuum electrode must be kept in close contact with the skin to prevent disa- greeable sparks. The strength of the secondary current from the .r-ray coil should be sufficient to spark across a H-inch gap. and the poles of the coil should be placed o inches apart if the limbs are being treated, or \ inch apart if the current is to be applied to the gums or in the nose. The distance between the poles regulates the strength of the application in accordance with the sensitiveness of the part. The author has had especial success with this method in infantile paralysis, constipation, and chronic neuralgic affections. Or. in another way of producing muscrlar conn-actions, the d 'Ar- sonval transformer may be used and two metal electrodes applied to the patient, one of which he may hold. A short air-gap is made in the circuit with the patient and powerful painless muscular contractions are excited ( !'. F. Strong). Local applications of high-frequency currents perhaps penetrate more deeply than other forms of electricity which are propagated to a great extent over the surface of the body. The deeper tissues share the heat in <: effect of high-frequency currents. The activity of lymphatic and other glands is increased, and if the electrode is in the rectum the secretion of mucus in the rectum and bladder is increased. Thera- pcutically, this acts as an active stimulant in tuberculosis and other chronic inflammations. Sometimes this application excites a move- ment of the bowels some hours later. It always produces a tonic effect upon the entire nervous, vascular, muscular, and .-ecretorv structures of the bladder. The same effect is perceptible about the external gen- itals and vigorous erections are produced. If applied through the clothes, underclothes, or bandages the dis- charge from glass vacuum elect rodes has much more spark effect. This sometimes produces decided itching at the tune of the application, but it the strength of the current has not been too great, and the clothing has been quite thin, this sensation quickly disappears. The current may be applied with nood results even in the case of a limb all bandaged [p '. 'r trinity eczema. Too lonir or too strung an application, or one too loim without moving the vacuum electrode from one nother, or with too much -park effect, will produce redness ot the -km which may be quite unpleasant. t ie can be observeil. The ./--ray ha- an alterative, and high-frequency CHIT' ' ' ' Like many othei experimentally kill b HIGH-FRKQUKNCY CURRENTS 571 therapeutic use depends very little upon any antibacterial property they may possess. Applied over the abdomen high-frequency currents stimulate gastric and intestinal peristalsis. Most of the general systemic effects may be produced by the appli- cation of vacuum electrodes over a considerable portion of the bod}', and, providing the current passing through the vacuum electrode is strong enough, it seems to make' little difference whether the patient is holding a metallic electrode from the other pole of the d'Arsonval or whether it is entirely unipolar from the Oudin apparatus. Effect of Local Applications of d'Arsonval Current*. These may be made by direct metallic contact, as by metallic electrodes, from the two terminals of the small solenoid, and in that case the effects are the same as from the general application, with an additional local analgesic, resol- vent, vasomotor, and trophic effect. I ndircct application* include those of sparks or effluve and those by vacuum and condenser electrodes. Their effect is both local and general. The (jcnerul effect is partly the same as that from general applications, lowering arterial tension (except when glass vacuum electrodes are passed lightly up and down the spine with an adjustment of apparatus producing great spark effect) and stimulating metabolism and similar effects, but it has also an effect due to local congestion and a conse- quent reflex influence upon every organ in the body. It gives origin to a change in the chemic and physical state of the blood which affects the protoplasm of the red and white blood cells, whose exchanges become more rapid, and to changes in the blood-plasma. Toxic or inflammatory products are more quickly eliminated. The local effect of local indirect applications of d'Arsonval currents is important. It differs considerably according to the method of application. A glass vacuum electrode, making a good contact with the surface of the skin or with any of the mucous membranes, while a good contact is made with a metallic electrode from the other pole of the d'Arsonval apparatus, produces no sensation but that of warmth if a current of moderate strength is passing through the patient. 150 ma. for instance. Hut this seems to have a cumulative effect, and the vacuum electrode becomes uncomfortably hot after being used in the rectum for more than five minutes. Rubbed rapidly over the surface with powder to insure a good contact, a much stronger current may be used without discomfort from heat except in sensitive regions like the face. The glass becomes quite hot, however, and fatty material, de- rived from t he skin and mixed wit h the powder employed, forms a white crust on the surface of the glass almost as hard a- enamel and requiring soap and hot water to remove it. The skin becomes somewhat red- dened from an application of a strong current of 200 ma. or more. The character of the application may be varied somewhat. of millianiperes may be increased without changing the of the induction-coil. The voltage mav be increased independently of the amperage by increasing the length of the spark-pap: this produces a greater spark effect from the glass vacuum electrode. The great"!' the amperage and the less the voltage the more purely d'Arsonval is the application, and the greater the voltage, with a corresponding reduction in the amperage, the more purely Oudin or high-frequency high-tension does the application from glass vacuum electrode- become. '.><_ MKDICAL KLK< TKHITY AND RON'HiKN KAYS The local effect of ula-s vacuum electrodes connected with the i ' \rsi inval apparatus and t he current . so regulated as to produce warmth without spark effect id'Ar.-onval character), is hyperemic ; sedative of sensitive nerves, both near the surface and deeper seated; antiphleg- masic in all kinds of inflammation, acute or chronic, simple or infective; and trophic, -i imulat im: the tissue- cells to healthy activity and develi ipnn-nt . The local effect of id ass vacuum e'ect rodes. connected with the d 'Ar- sonval apparatus with the current adjusted so as to aive the greatest spark effect and verv little amperage, is the same as if it were connected with the Oudin resonator, but it will be described here for convenience. A small vacuum electrode. {- inch in diameter, held near one spot for a few seconds applies a shower of fine sparks, which anesthetizes the skin to such an extent that a more severe application does not cause pain, and even slight operations could be performed. Holding the glass electrode close to the skin or in contact with it the sparks are more severe, and presently the skin turns white, and a few minutes later a /.line of intense redness forms around the white area. It takes only a minute's application at the same spot with the strongest discharge to cause local -uperficial destruction. The subsequent course is for a sort i if pus blister to form, looking like a vaccination pust ule. This gradually hanires to a dry scab, which leaves no scar if the application has been comparatively mild, as for treating a wart, or quite a distinct scar if it tia- been severe, as for the destruction of an epithelioma. A larger vacuum electrode, which may be applied to a surface 1 or '2 inches in diameter, mav he passed quickly over the surface without making very close contact, and produces with this high-tension discharge hyprrcmia of the surface and a countcrirrit ant effect, and an effect upon painful nerves which may not be desirable in certain cases: it seems to "key them up." The skin may even be made somewhat red and rouirh by too frequently repeated applications with too -real a -park effect. The application is a powerful resolvent and antiphleg- ina-ic and usually relieves pain. Tin /_'//"< r/ nf tin' V in/it /i/i"/'.*. \isible Im'ht is produced by the pa-sa.ire of a cur- rent ot elect 1'icit v through a tube exhausted to about ,,-,',,,, atmosphere. I'.'i' fo'oi Varies \villi the exact decree of vacuum. Some ot these lubes are tilli-d with a beautiful blue, lilac, or violet color, and in some there are - , patches of the apple-green color which indicates the pfe-'-nce ot an appreciable amount of .r-rav. The visible li^ht from one ot the va<- nun electrodes ha- no demonstrable physiologic or if the current t hr< 'U^h the part ial vacuum, and especially between different parts nf the lube and the patient mav be seen passim: 1 alomj 'lie outside of the tube ' ' ,\ ill the i';: 4 !' tit . produci - nltrnriuli t rnilid- . e (luori iscence 111 a piece o| \\lllemite held near ; room The ultraviolet ray thus produced has its ! H rating o/one from the atmosphere, and of being -uperiicjal !.. ;.-' M i he -kin. 1 1 i.- ha nil v to be ; vi' ill ! ra v - ab-orbed I r. t he hoi iv during a o! VaciiUI ' : - t a I-.' .- all Y more < lirect ] >al't It 1C efject . i i hv tin application of t he vacuum elect rode- and HIGH-FREQUENCY CUHUKNTS o/i? ultraviolet radiations i> very important. Rubbing the vacuum electrode over perhaps a four! h of t he surface of the body for ten or t we] ve minut es bathes the patient in o/one gas for that length of time. It is absorbed by the body just as carbonic acid gas is absorbed from bathing in water charged with that gas. Its general effect is that of o/one inhalations, increased processes of oxidation in the blood and every other tissue. Nitrogenous substances are completely oxidized and leave the system as urea instead of being incompletely oxidi/ed to form uric acid, some of which would be eliminated, but some of which would form an irritant deposit in the joints or nerves. The odor which is noticed upon the patient, and which may even cling to his clothes for several hours, is chiefly that of nitrous acid produced at the same time as the o/one. This acid may play some part in the effect produced by the applica- tion. Yacuoles or cavities filled with o/one may be found in the tissues directly subjected to this treatment. In addition to the effects described the glass vacuum-electrode application has other effects which are dependent upon the nature of the currents which it transmits. These maybe either those of the low- tension high-frequency type, called d'Arsonval currents, or the high- tension high-frequency currents, of which the Oudin resonator yields an excellent example, or the current from a static machine, or the cur- rent produced by one pole of a Tesla coil. These are the types of current which are most often applied by means of the vacuum elec- trodes, and they have quite different effects, especially upon the general system. Systemic Effects of High-frequency Currents. Experiments .^hotrint/ th< Ejl'ci-t of High-frequency Currents on Aninmlx. D'Arson- val's experiments 1 showed in a general way that high-frequency cur- rents caused the blood-vessels in a rabbit's ear to dilate at first and then to contract and remain so. also that the general blood-pressure was first reduced and then increased. Carvallo- found no effect from the autoconduction cage, but that there was an effect from the application of the currents directly to the skin. Strong currents cause sensation and a motor reaction and a fall in blood-pressure. Boedeker used the apparatus already described as the German ar- rangement. He found no effect from the autoconduction cage, but a decided effect from a direct application to the skin, a primary phase of vasomotor contraction and increased blood-pressure. According to Doumer, :! of Lille, France, the effect of high-frequency currents on the cells is the fundamental one. and this can be demon- strated on vegetable as well as animal cells. O//.xv mil in/is ['/KI tin Ejjtct of High-frcqucnci/ ('nrn-nt* Applied /.<>i-ii!li/ in Mnn. [) 'Arsonval's observation, that after a long or strong enouu'h application the skin becomes reddened locally and local and sjj-neral perspiration sets in. is a matter of daily observation by the aut hoi 1 when using vacuum elect rodes con nee ted with the Oud tor. D'Arsonval finds that a change in arterial pressure is n diseases, such as diabetes, from ; dVWl Midi.. |S!i7. i 1 -('. \\. XIII. Internal Me. Physiology, p. I '20. ' :i I..- Itailiuin. Sept. 1.",. 1 '.(()."). 574 MKDICAL KLKCTKICITY AM) KONTllKX RAYS held in the hands and connected with the small solenoid. Some patients show a material fall and others a material rise in blood-pressure. Moutier found that sparks from an Oudin resonator applied along the >pme produced a very rapid rise in blood-pressure, amounting to 1. ^. ti. 7. or even s cm. of mercury. These and static sparks along the spine are the best methods of treatment for neurasthenia with hypo- tension. Doumer and < hulin find that high-frequency high-tension sparks turn the skin white, and that this is succeeded by an erythematous blush which may last for hours. The aut hor has observed this especially in cases where high-frequency and high-potential sparks are applied from a metallic electrode, as for the destruction of epithelioma, but in these cases there is apt to be a central pure white area where the sparks have been applied, surrounded by a /one of intense redness. According to Oudin 's observations, an implication of the high-fre- quency high-tension ehMuve to any portion of the body produces an almost instantaneous vasomotor spasm which suppresses the capillary pulse in the hand. \Yhen the application is stopped the capillary pulse gradually regains its original amplitude through a series of oscil- lations. The monopolar effluve of high-frequency currents increases arterial tension 1 . THE EFFECT OF GENERAL APPLICATIONS OF HIGH-FREQUENCY CURRENTS Effects of General d'Arsonvalization. A current of (i(K) to 1000 ma. from direct metallic contact or by induction t ra verses t he body, often without any sensation and always without pain. Kqually strong cur- rent- from vacuum electrodes or spark electrodes or eflluvers. or from condenser electrodes or autocondensat ion pads or couches acting as such, mav give rise to sparks which are anesthetizing or painful or cauteri/ing or destructive, according to their si/e and the length of time during which they are applied to one spot. There is a sensation <>f warmth in the hands from holding the metal electrodes in autocon- lensat ion. There are increased tissue ch an ires, more rapid oxidation, more rapid reduction of the oxyheinoglobiii in the blood, increased elimina- tion of waste products in the urine. The effect is due to an action upon the Lire at sympathetic nerves controlling vasonmtor, secretorv, t henm >ireiii t ic. and peristaltic functions. The general applications have little or no effect upon the central nervous -vstem controlling -ensation and voluntary movement. It has special effects upon the protoplasm of tissue-cells everywhere, increasing the rapiditv of their natural fliemic changes, and special effects on bacteria and ferments and animal poisons. I hen- i- a soot h ing effect upon any painful condit ion. and sometimes this mav be accompanied bv slight drowsiness. Sometimes, however. t hen i- a -en -e i ,f e \lnl a rat ion. and one pat lent ot the aut hor's felt like ualkiiiL 1 all the \\ay home (twentv mile.-) alter each treatment. More often, however, there i.- no immediate chantre in the uav the patient t on the blood-pressure is ot great importance, and like of electricity, high-frequency currents ad as regulator,- of ' producing a marked effect upon a healthy person. ! \llicrt \\ i ill, l.i- Uaclimn. Sept. \.~>. r.tn:., p. :;i)j. HKill-FREQI'ENCY CURRENTS 575 The same is true of the effect of digitalis upon the blood-pressure, accord- ing to the observat ions of 0/yhlarg. 1 He found that when an infusion of digitalis is given to individuals with normal circulatory apparatus in quantities equal to that administered to persons with valvular disease, there is no increase in the blood-pressure or in the amount of urine excreted. In cases of rheumatism, gout, asthma, and kidney disease, and in neurasthenia with high arterial tension the application of high- frequency currents causes a reduction of the blood-pressure. The autoconduction cage has been found more effective in this way than the autocondensation couch or the application by vacuum electrodes, but any method will produce the desired effect. This reduction is progressive from one treatment to another and occurs even in cases of arteriosclerosis, for which high-frequency currents are an excellent treatment. The observations of Moutier and Challamel- show that a reduction of 5 to i) centimeters of mercurial pressure takes place after the first treatment with the cage in cases of high art ('rial tension. Five centimeters is the maximum reduction from a single treatment with the couch. In cases of defective metabolism we find increased oxidation produced by high-frequency currents. In gout and rheumatism the urine con- tains an increased amount of urea, while the uric acid disappears. In other words, the nitrogenous matter becomes more completely oxidi/ed in the system. And this effect is not a temporary, but a permanent one of increased tissue activity. The energy is so great that it produces a tonic effect upon any person within 10 feet of the apparatus. The present author enjoyed extraordinarily vigorous health during the four or five years following the introduction of these currents, in spite of the fact that the nature of the work confined him to the office practi- cally all day. winter and summer. The oxygen-carrying capacity of the hemoglobin of the blood is increased as well as the amount of hemoglobin. The human output of carbon dioxid is sometimes increased from 17 to .'->7 liters per hour, and there may be an increase in heat production from 70 to 127 calories per hour. The bodily temperature docs not vary more than a small fraction of a centigrade degree (d '. \rsonval ). The amount of phosphoric acid in the urine is increased. The toxicity of the urine is increased. There is an increased elimination of CO,.' The application is apparently innocuous, and there are no special contraindications, except that perhaps it is less likely to be of benefit in acute inflammatory conditions than elsewhere. And it is but fair to i-tate the belief of some observers that it is likely to precipitate an acute attack of gout, though this appears very doubtful. The author lias used it successfully in the treatment of acute attacks. Sometimes an increase of arterial tension will be noticed in a healthy person in consequence of the application. High-frequency currents produce a reduction in weight on account of the increased oxidation. This is most noticeable in cases of obesity. The Thermal Effect of High-frequency Currents. Somerville ; has especially called attention to the increase 1 in surface 1 temperature and also in the temperature in the mouth which occurs during the appli- 1 Wiener klinischo Rundsthau, April !.">, 1000. - Academic dcs Sciences. Paris, Feb. i:>-23, 1905. 3 Medical Kleetrolo^y and Radiology, -May, 19(K5. ")/() MKniCAI. ELECTRICITY AND KONTdKN RAYS cation of high-frequency currents. This increase amounts to from \ to 1 F., and has been verified by Lacomte, Benoist, d'Arsonval, \\Vrtheim Salomonson, and others. F. De Kraft 1 (motes Sommerville'-' in regard to the rise of surface temperature from high-frequency cur- rents. The autocondensation couch from one end of the solenoid and the handle from the other end of the solenoid and 2~>() ma. cause 1.} to t'r F. rise, especially of the flexor surface above that wrist; tiOO ma. in one case raised t he surface temperature' as much as 14 F.. but the patient could not stand the .-welling of the arm bandaged with the thermometer more than twelve minutes. Under the tongue the temperature rose only 1 or 2 degrees. Various explanations are offered. Somerville says, "This ri, t;. () r even !) cm. of mercurv. and in a few treatments the blond-pressure was alwa\> reduced to normal, about b"> cm., when' it would remain for several weeks. has toiuid that the pressure mav even be reduced to the same beneficial result- from the use' of the ion cage in cases of neurasthenia with high arterial tension, iidon m .1 rases not subjected to any dietary regimen; Doumer ^I''- - 'ase nt Parkinson's disease and I.e^-endre in ' 1 1 - ] : i . all' ' 1 a 1 1 1 ( ,, T , . . on. v V .|,,ur. \n'li. '.; I, 1 '. nt (TKHKXTS 577 of mercury. This increased blood-pressure disappears after about twelve minutes. The difference in the results may be due to difference in the appara- tus, as explained on p. f>o2. Furthcf Detdila J the Application of Hiyh-frequencij Current* in !!///nrt< nxton. --Short t real inents of not more than five or ten minute- are best , and should be given two or I hree times a week. Diuretics and laxatives are desirable to avoid the effect of increased metabolism at the beginning of the course of treatment. Apo.stoli found that the autoconduetion cage is contramdicated for certain classes of diseases- hysteric anemia, debility, senile rheumat ism, and certain cases of diabetes, anemia, and chloro-anemia. Some of 1 liese patients experience nausea or vertigo and depression. Denoyes found thai many patients with different diseases experi- ence no sensation, while others notice a prickling sensation or that the face feels hot, and others feel a little vertigo or sense of slight intoxica- tion aft er the t reat ment . Moutier notices that patients \viih low arterial tension feel badly if treated by the autoconduct ion ca,u'e. and consequently patients \\ith lithiasis ami hypotension requiring high-frequency treatment should receive this in the form of sparks applied along the spine. This tends to raise tin' blood-pressure. Patients with hypertension treated by the autoconduct ion cage sometimes notice slight formication, sometimes a decided feeling of well-being, but generally no sensation at all. The pulse rate is but slightly affected. The enlarged heart in old cases of hypertension becomes smaller. Cases in the hospital and on a strict diet of bread and milk often have a normal arterial tension after three treatments in the autocon- ductmn cage. The rapidity of the results i> usually proportional, not to the severity or the duration of the disease, but to the hygiene of the patients. The results are equally good in cases where a strict diet without high-frequency treatment has proved unavailing. Experiments have been reported by ,)osm'. Loeper. and Josserand upon animals whose arteries have been made atheromatous by long- continued high arterial tension from repeated injections of adrenalin. High arterial tension seems to be the cause of the arteriosclerosis which follows. Aiitocoiiduetion of high-frequency cur- rents affords the best means of treating arteriosclerosis by removing its cause, high arterial tension. hlfcftnj . \ />/>/ icfil inns tit j f n/h-f /'< perhaps TOO ma. when the patient is seated upon the pud, and onlv 100 ma. when lie is not. This would apparently indicate that ('()(( ma. of high-frequency current traverses the patient 's body. The treatments hot live or ten minutes. They have not in the author's cases been followed by the very marked fall in blood-pressure reported bv Mouiier from the autoconduct ion cage. but by a more gradual improvement in consequence oi a course oi treatments. Pat lent s with arteriosclerosis resulting even in hemianopsia and other apoplectic effects have been restored to apparent health. Delherm and Laquerriere, 1 after considerable experience with the effects of the uutocondeusution couch and the autoconduct ion cage, and following as closely as possible the technic employed by Moutier, have come to the following conclusions: ill That the immediate re- duction in blood-pressure is not us constant or us marked as others have observed it to be. I'Ji The permanent reduction is decidedly less marked and less constant. (3) Kven with a suitable regimen high- frequencv currents do not surely prevent the bad effect- of arteriosclero- sis. ill There does not seem to be a marked reduction in capillary blond-pressure, but there is a decided increase in the amplitude of the capillary pulse. (')) The best clinical results in high arterial tension are apparent in patients who can be classed under the general heading of congestion (arthritic, gouty, urteriosclerotic. etc.). I('M Benefit does not alone depend upon an effect on the blood-pre.-sure. but perhaps more upon an effect on general nutrition and the urinary elimination. The modification in the capillary pulse produces a better aeration in the luni;-. a more marked elimination ot carbonic acid, and a more active fixation of oxygen bv the blood. This increases the rapidity of the exchanges and the activity of thermogenesis. Toxins are more com- pletely eliminated. Doumer's Results with a Measured Electromagnetic Field in the Autoconduction Cage. Believing that differences in clinical results may follow differences in the strength ot the field in which the patient i- placed, he regulates his apparat us so as to produce in every case a field of .")()().()()() (lauss. (Moutier 's field averages loo.ixii) (iaiiss.) The meter lor thi- observation is placed in view inside the aut oconduct ion <;;_'. Tli'- necessity for such a meter lie- in the fact that the strength of the held varies with different apparatus, and even with the same ' i.~ .: ':.' interrupter nr the -park-Map acts a little differently. lie uses ;i |J-inch induct inn-coil as the source ol his power and plate collden-ef.- 1H| llHTSei 1 HI oil. AH tour patients reported upon- -howed a steady improvement '' 1 v to I '.'>.. i. ] i >. 1 7.7"). and 1 ti mm. 1 he t real men t last ed ten in i from three to iitteen treatments were required. .' M remained normal alter the treatment-^ were di.-con- ' ' pa'ieni had a lar^e hydrocele, which disappeared (luring cour-e oi ; i a t meiit without an v direct apphcat ions or local t n-ai - n) ii - have found that the same current- applied in cases i-e the arterial ten-ion, but the higher tension >:a ' he ' > idm resonator are more effect ive in this direction. ,|'i:i, firicit.' \1. -1 . July 10, l'.'<)7. : July ;_'.">, I'.'Oi). [.. .") .")(',. HKiH-FKI-XjrK.NCY CUKKKNTS 579 The effect upon the blood-pressure is not due to a depressing effect upon the heurt. Thi' d'Arsonva! applications relieve the heart from the strain encountered in driving blood through the contracted arterioles and capillaries, and the Oudin applications have a tonic effect upon the heart as well as upon the vasomotor system. Effect of High-frequency Currents in Diabetes. D'Arsonval and C'harrin, Boinot and Poncy, 1 Apostoli and Berlio/, Reale and Ren/i, and \ inus have treated numerous cases of diabetes by approxi- mately the technic to be described. The secondary terminals of an induction-coil are connected with the internal armatures of two conden- sers and the spark-gap is between the latter. The outer armatures are connected by a small solenoid, from two turns of which wires lead, one to a metal electrode held in the patient's hand and the other to a foot- plate or foot-bath making contact with the patient's foot (Fig. 370). Every one of the authors cited report uniformly beneficial effects upon the patient's general condition, whether tin; sugar disappears from the urine or not. In most cases the sugar was markedly re- duced in amount and in several cases it entirely disappeared. The treatments usually lasted ten minutes, and were given every day for ten or twenty days. Autoconduction cage treatment did not lead to a disappearance of the sugar Fig. 1570. D'Arsom-a! hiph-f re- in four cases reported bv Yinaj and queney currents applied by two , -- " J electrodes for diabetes. \ lette. Colin also finds that high-frequency applications do not modify the amount of sugar. Boedeker, using an apparatus with the spark-gap between the external armatures, the (ierman method (Fig. 34(i. p. oo2). found that high-frequency current > did not change the amount of sugar, but did very markedly improve the general health. In one case of diabetes there was marked acetonuria. which completely disappeared during a course of high-frequency treatments, but returned after the treat- ments were stopped. Denoyes has obtained excellent results as to general health in cases treated by the autoconduction cage, but the circumstances of the patients as to diet, etc., were such that the effect upon the sugar could not be determined. Cases of diabetes treated by the author have shown a reduction in the amount of sugar from 2700 grains (1M) grams') per diem to a mere trace, and this has been associated with a very great improvement in general health. The treatment has been by the application of a glass vacuum electrode over the abdomen, the current being a unipolar high-frequency high-tension discharge from the Oudin resonator (Fig. 371 ). Applications of the .c-ray have been made over the region of the pancreas and liver. Other Effects of High-frequency Currents. Capillary vasocon- striction is most marked when the high-frequency high-tension efiluve or sparks are applied to a part of the body symmetric with that in which the capillary pulse is studied. The lowering of blood-pressure produced by d'Arsonvalization is es dc la ^ucicte de luuloiru 1 . July '.>\. 1SC7. 580 followed hv a ri.-e uhich lasts for a considerable time, just as the con- t faction of thi' capillaries from the < hidin application i.- succeeded by a prfiod of capillary dilatation \\ludi may even be permanent. Cases in \\liiih hi^h-t'rcquency hi partly considered in the paragraph on Pulmonary Tuberculosis i p. (,07), The technic for such cases is iriven in detail there. The beneficial effect in p-neral or local tuberculosis seems to be due. not to ;mv dii'ect effect upon the bacilli, but to a tonic effect upon the tissue cells and upon ail processes of metabolism. The results ot 171. \ (MI ni liiirIi-frciiHi-iii-\ c-iirrrnt The irrent eniployeil in the follou'inii case treated by the authoi' was not a hi'_:'h-l t'eijueiicv luit a vibratory current, having a similar l hi -ra pi it i ' if ' d : ii i hi.- class ot case-. I In pat lent was an old woman a' St. !'>,:!'' r >! >.'! i' "A - ('lime, who had undergone an opei'alioii for e\ten-l\'e ' iln rciilo.-is of the dof-al vertcbi'a 1 seven months previously. A di " ' ' -'ill remained, and throimh ii (he prone found an e\ti-u-]\'e area oi -oftefii'd bone, I he treatment consisted in the ibi n one llol/.knecht unit ot fays No. ^ 1'ieimi-t from an .r-rav tube placed at a distance oi Id indies from the anticathode to .in ' /. ici a '.'. ei ',, (in i he -a me da \ -. and al-o on one oi her da \' each ''''. ii electrode connected \\nh one pole of the ,c-rav coil wa- applied ' < r 'he affected area tor about ten minutes. The Hicii-FinxH'KxrY rruKK.vrs 581 rrhcn and cervical () milliamperes, and should be applied for ten or fifteen minutes with intermissions to allow the electrode to cool. ;>NJ MF.DICAL ELECTRICITY AND RONTGEN RAYS A certain amount of massage is often beneficial, and this may be pro- duced by moving the electrode in various directions. The treatments should be given three nine.- a week, and should be suspended during menstruation. The position for the patient is upon her back, \vith the Ices raised and resting upon crutches, as described in the paragraph on rectal treatment 'p. (ill). It i> much pleasanter to introduce the electrode before the current has been turned on, avoiding the sparks which wi >ul< 1 i it herwise occur. M i ti'orrfnti/iii. -Cast's due to small h'bromyomata or fibrocystic tumors iir without apparent cause have been successfully treated. 1 An ordinary copper electrode is introduced into the uterus, the vaginal portion beiiui insulated by a rubber tube. The high-frequency appara- tus may be connected with a static machine or with an ./'-ray coil, and the application should last about ten minutes and be repeated once or twice. If a static machine is used the application will probably have to be of the full available strength, but with a coil it should be regulated .-0 that a current of about 150 milliamperes -hull pass through the copper electrode. The cases required only two or three treatments, and in all three reported the effect appears to have been permanent. Other observers have not iced an uncertainty about t his effect in different cases, and. -till others i. \postoli and the present authon have noticed a well-marked emmenagogue action from high-frequency currents. This may not be the case, however, when applied in the cavity of the 11 tern-. I'' I >'i< K.i'nilud N. -These case- can very often be saved from an operation by this treatment. The vacuum electrode ha.- an insulated stein, and the portion from which the current emerge- is about 2.1 inches lom_i and -' inch in diameter. No speculum is required, the tip of the electrode being pushed up into the vairmal fornix as close as possible to the lesion, and then a current ol 150 milliamperes i.- turned on. This may be a unipolar application from the Oudin, or. if from the d Arsonval, the patient must hold the other electrode. After five minute-' vaginal treatment a similar application of 200 milliamperes : n ade over the lower part of the abdomen for ten or fifteen minutes. Powder i- used to secure a good contact and allow the vacuum elec- trode to be moved rapidly over the surface without .-parking. The pain! il area is especiallv treated. Mehet oi pain and improvement in -':''!! L 1 t li are verv prompt, and some weeks later the gynecologist is :'. to -ee the difference, produced locallv. It -ecms probable that thi- i- the lie-t electric application for these cases, and the author has cun :-.;.- had pcrsi-ted after operation and all kinds of medicinal appli'-at ion-. ''/. 'I lie au'lior sir^L r ''st- the use o| high-frequency currents it! f-a-i - in '.vhich there i- no assignable cause for sterility or in which flii 1 -uppo-i 'I cause h,-i- liren removed bv surgical measuies. It slimu- late- iterine ;IM( ] ovarian function- but also acts as a tonic upon he .'. ho! i -.-tem. The large uninsulated vaginal vacuum electrode .nil a current ot ].)0 milhampcres tor ten minutes I hfee ' 1 !!!'- a '.' ee[,; I 1 e 1 1 a> -een t 1 1 1 - t fea t lliell t followei 1 by 1 he prompt ' ' 01). and ;ft.rninn of the type which will yield to manual manipulation -houl'i find in high-frequency currents a most valual>le 1 F.-iiichi.n V. [i-tiii nftici"! df la Sucicti' francai-c 31\ is especially effective in the treatment of gonorrheal arthritis and of gouty deposits about the joints. High-frequency Currents in the Treatment of Genito-urinary Diseases. Chronic Orchitix or fcjtiditli/n/i/i*.-- The author has suc- cessfully treated cases of long-standing swelling due to injury The treatment has been by a combination of the ./'-ray and high-frequency currents, and care has been taken to shield the sound testis from the .r-ray by ./'-ray metal. In the light of the recent discovery that the .r-ray produces sterility by killing the spermato/oa a great deal of judg- ment is required in determining whether to use the .r-ray as a part of the treatment. It certainly should not be applied in causes of a simple chronic inflammatory tvpe. Hut in the more threatening cases, where the treatment may save the patient from an operation for the removal of the testis. the .r-ray should certainlv be combined with the high-fre- quency currents. The method of application is by exposure of the testis through a hole in a large sheet of .r-ray metal, the tube being at a distance of about 10 inches, ravs No. 5 Henoist. With a J 2-inch coil, a YYehnelt interrupter, and the primary winding giving the greatest inductance., a primary current of '! amperes and a current of 1 or 2 milliamperes passing through the .r-ray tube the exposure would 1 Bonnefoy, Bulletin Oflicicl , 11*10, p. 408. MKDICAI. KLKCTHIC1TY AND H()NT(iKN KAYS l>c one or two minutes, or III, t hree times a week. The high-frequency ap]);ir;itus might he the d'Arsonval transformer, in \vhicli case the patient, lying on his hack, would hold a metallic electrode, while the ot her elect rode, a glass vacuum tube in an insulated handle, is applied over that entire side of the scrotum. About 12") milliamperes would be the proper strength of current with the d'Arsonval. A spark- effect is to !e avoided, the electrode should be kept in motion, the application should last about ten minutes, and should be made three limes a week. The ,r-ray is especially effective as an alterative and high-frequency cm-rents as an eliminative. The combination would be ideal in all these cases were it nor for the drawback mentioned above, and which makes it desirable in many cases to use the high-fre- ijuencv currents alone. 7 itht rt'ttloxtfi and /'iim'tr <>t nn/j /xi/i <>/ tin t/i mtu-uri unrij ti'tii't are favorably influenced by high-frequency < '.irrents a.- an adjunct to r-ray treatment. The amount of pus and epithelial detritus which will be gotten rid of by a single combined treatment in a case of tuber- culosis of the bladder or kidney is astonishing, and the subsequent clearing of the urine and the relief of pain and the improvement in regard to frequency of micturition are most gratify ing. The vacuum electrode is applied over the kidney or bladder, as the case mav be, and in the latter case a rectal electrode, either vacuum or of solid metal, is efficacious. A current of !")() to 200 milliamperes is to be applied over thi 1 kldliev; about 1 .")() milliamperes over the bladder; the electrode IS to be kept in motion; and the application is to last fifteen minutes three times a week. The current for rectal use is about 1 ">0 milliainpereK with a vacuum elect rode, and may be much st rouge r, up to 100 milliam- peres, with a metal electrode and d'Arsonval current. Thfse two diseases, tuberculosis and cancer of the gemto-unnai'v system, are further discussed in t he sect ion on ./'-ray t re;,t ment . S [xisniixlir xtrift arc mav often be cured bv high-frequency currents. Kither a rectal or a urethra! electrode may be used. The latter may In- either a ulass vacuum electrode or an electrode consisting of a metal roil covered wit h hard rubber. The latter type gives a shower of line spark- even when m contact with the mucous membrane. A cur- rent oi 100 milliamperes mav be applied m the urethra for about five minute-; three time- a week. The current should be interrupted occa- -lonallvto prevent i he elect rode from getting too hot. ami some greasv lubricant, like ravelin, i- better than any of those which are soluble m wat'-r, \ lubricant of the latter character will sometimes be dried ip by the |,i v oj ',\\c current and it will be difficult or painful to remove the electrode. dimnrrtim. \ \ i-li -frequency current s have so decided a bactericide 1 " ' in laboratory work that it i- only natural that they should have been applied ijie treatment of gonorrhea. Sudnik ' treats such a ih'- p< ms m moi-t ab.-orbent cotton, over which is a sheet ot /me to wliich the current is conducted, or the penis is in a Aim i] i ..'<'' il)i'ilntic. vol. ii. p ;;i:;, uote. | l>v I-p-uinl. HIGH-FKKQl KNCY (TUKKNTS 585 U'lass tube with a metallic bottom and containing boric acid solution. One wire is connected with the metal bottom of the tube, while the wire from the other pole of the d'Arsonval transformer leads to a metal plate, which is placed over the perineum. In women Sudnik uses a moist tampon large enough to distend the vagina and secure contact with the entire mucous membrane. This is connected with one pole of the d'Arsonval transformer, while the other metal electrode is placed over the hypogastrium. His results have been very good, the gonococci being killed almost immediately, but t he discharge persist ing for a week or two longer. Burdick 1 has 1 reated obst in ate cases of gonorrhea: ( 1 ) I)u" to streptococcus in pure culture; this yielded rapidly to treatment by a glass urethral electrode and Oudin resonator. ('2) Mixed streptococcus and gonococcus infection; did not yield to high-frequency currents, but did yield to the x-ray applied so strongly as to produce a painful reac- tion upon the mucous membrane. ('.)) Gonococci mixed with tubercle bacilli; high-frequency currents failed, and rather a. high vacuum jr-ray t ube caused a cure in seven or eight days. In t he female high-frequency currents from vacuum electrodes in the vagina sometimes caused a cure in two treatments. In a case treated bv the present author the ./-ray and high-frequency currents proved ineffective against gonococci. The technic consisted in the application of rays \o. 5 Benoist every three days, the length and strength of the applications being such as to just fall short of producing a reaction upon, the skin; and the use of a urethral electrode connected with the Oudin resonator. The t real ment was begun during the first week, and was continued for several weeks without causing the disappearance of the gonococci. It was noticeable, however, that the discharge and pain were very much dimin- ished by the first treatment, and never returned to any extent. The patient had had several previous attacks of gonorrhea. A better method, introduced by Sudnik, 2 employs the bipolar d'Ar- sonval current. A metallic electrode is, pressed against the perineum, and the wire from the other pole of the high-frequency apparatus is connected with a metal douche bag from which a urethral injection is given. The beneficial effects are independent of the nature of the fluid injected. A twenty-minute application is necessary, and it should be as strong as possible. Sudnik uses a 14-inch induction-coil and 4 large Leyden jars to excite his high-frequency apparatus. Sometimes in cases in which treatment is applied at the commencement of the dis- ease there an 1 less discharge and shreds after the first treatment, but generally the improvement is gradual. Fiili/unit/on in I'd pillonid of the Blmlilt r. - Leo Buerger and A. L. A\olbarst :; and Kdwin Beer 1 were among the first to report the applica- tion of high-frequency sparks in the treatment of papilloma of the 1 bladder. The applicator is passed through a cystoscope, and consists of a metal point at the end of a flexible shaft made up of a spiral spring covered with rubber tubing. The Oudin re-onator is adjusted to give a hot spark only i inch long. The applications last about five minutes for a large papilloma and only a few seconds for a tiny growth. MEDICAL ELECTRICITY AND RONTGEN RAYS Dr. H. D. Kumiss 1 reports the application of fulguration for freeing a calculus impacted at the vesical end of the ureter. A stream of sparks produced suflicient destruction of the overlying mucous membrane to allow the stone to escape a few days later. The bladder should be full of water during fulguration. (.'i/xtiti.*.-- An instructive case is reported by Crane.- A lady of fifty had suffered for four months from very frequent and painful urination. especially at night. The urine was alkaline and contained of) per cent, of pus. A slender vacuum tube was introduced into the bladder and the current from the Oudin resonator applied for fifteen minutes. She' slept nearly all night and could urinate without pain. Twenty treat- ments, combined with the internal administration of urotropin, effected a complete cure. This agrees with the author's experience in more serious bladder cases, in which the vacuum electrode has been intro- duced into the rectum or applied over the lo ,ver part of the abdomen. Fig. 37-L Dimmer's rectal is. Doumer 1 reports most favorable results in 122 cases of acute, subacute, and chronic prostatitis, congestion of the prostate, and prostatitis with vesiculitis. One method employs a metallic electrode (Fig. :->74), passed into the rectum a distance of about 2 inches, and connected with the Oudin resonator and the strongest current and rather long treatments, eight to twelve minutes. Another method is bv means of an electrode with a glass sleeve (Fig. :!"">); care must be taken not io use a current strong enough to puncture the glass or to produce too iireal a sensation of warmth. Such an electrode may be connected with a resonator, but the latter should be regulated to pro- duce much less than its maximum discharge, efiluve without' sparks, and the application.- should not be longer than three io six minutes. Morion wave-currents from a static machine, or similar currents from one pole of the d ' A rsonval transformer while the patient holds an- ot her elect rode, give results similar to those from the Oudm resonator, h It are |e.-~ convenient and are less agreeable to the patient. .[fiftlu-iiti'titi of tin .[m-xlli<-fir !\u> / <>f ///'t/d patient showed a rapid tall in blood-pressure with only one treatment a week. He complained of a nervous diarrhea, spinal hy- peresthesia. and muscular weakness, especially in the morning. He was a pseudoneurasthenie with hypertension. The diarrhea and the debility disappeared after the first treatment, and finally the spinal hyperest hesia was cured. The third patient received three treatments a week. He was thin, on an insufficient dietary was constantly cyanotic. and had acute attacks of dyspnea at night, \\alking was difficult on account of dvspnea. and the trouble seemed to have been brought on originally by overexert ion. There had been attacks of pulmonary congestion and of acute nephritis. The heart action was rapid and suggestive of Bright 's disease and very arhythmic. Treatment was bv aiitoconduct ion and benefited the arhythmia very much, caused the disappearance of cyanosis, and improved the dyspnea so that the man could walk rapidly for several minutes. The night attacks disappeared. The nature of the dietary, which was partly milk, was not changed durimr the treatment. The fourth patient was a man ot sixtv: hemi- plegic; had had two serious congestive attacks during the last two years, and his high arterial ten.-ioii evidently exposed him to the danger iif another. There was spastic paralysis ot the arm and leg and intense mental excitability, especially at night. '1 he cerebral condition was improved from the moment the high-frequency treatment was begun. The spasmodic contraction- were relieved and walking became much easier. Constipation was relieved. There was only one treatment a week. Diet was moderate as to quantity, but unrestricted as to nature. '1 he /'/'//, patient was a vouni: man who was very stout and who per.-isird in overindulgence as to diet. He was gouty, dyspneic. albummuric, and had taken the cure at \ichv for attack- of severe .' trouble. He sought treatment on account ot the gout, which u'a- -o had thai he could scarcely walk. Autoconduct ion bv inean- ot a cane connected with the d Arsoiival t ran.-tormei 1 was applied three 'her with ihe high-frequency eflluve from the Oudin the painful joints, and a few -inu-oidal applications. much reduction in arterial tension until i he thirteenth HIT thai lime the joints were so much relieved that \ could be applied, and from that lime the blood-pres- lo about normal, the patient became able to breathe well, and became thinner, although still weighing 111- pi T-i-t ence in overeating was the cause of the ; d rial pn '--ii re. value "t high-t reqiiencx currents in i he treat- it h hi r _:h arterial ten -ion is large! V due to I he pub- HICH-FRKQrKNCY CURRENTS lished observations of Moutior, 1 of Mouticr and ( 'hallamol,- and of ( lay. :; A neurasthenic wit h high a fieri a I tension does not need t he rest cure, and i.- to he regarded not as {ill enfeebled hut as a poisoned person ((lay). No other means is nearly so effective as high-frequency currents in causing t he elimination of irritant -uhst ances and t he restoration of t he normal blood-pressure. L'nder this treatment there are increased cellular activity and increased respiratory movements and chemic exchange.-. The oxyhemoglobin in the blood increases and there is increased elimi- nation of carbon dioxid. The same increased elimination is shown bv changes m t he urine resulting from more complete oxidi/at ion of organic substances in the system. There is an increased amount of urea, (lav gives a detailed account of the result of treatment in 12 cases of neuras- thenia with high tension, and the subject is so import ant t hat his oh.-er- vat ion should he recorded here. 1 1 is high-frequency a p pa rat us consisted of a 10-inch RuhmkorlT coil with a \\ ehnelt interrupter, condensers, and a large d Arsonval solenoid or autoconduction cage inside which the patient was placed. A primary current of d amperes and a secondary current of :>.">() to 100 niilhamperes were used, and the application lasted twenty-five minutes everv other day. ( 'ase 1: Man aged twenlv-one. salesman, alcoholic ancestry, two brothers consumptive, himself a drinker and onamst. For six months he had Miffered from a sensation as of a leaden helmet on his head and a general feeling of lack of strength. Melancholia and tendency toward suicide. Well nourished and well developed. \o anomaly of sensation, tendon reflexes slightly exag- gerated, pupils normal, no Romberg symptom (difficulty of equilib- rium when the eyes are closed). In ten treatments the following changes took place: pulse rate, from 70 to S 0; blood-pressure, from H)0 to \'2() millimeters of mercury: daily amount of urine, from 1MOO to IdOO cc.; chlorids. from d to 10 grams per liter: phosphates, normal before and after: sulphates the same; urea, from 12 to Id grams per liter: uric acid, from o to 1 --',,",,- grams per liter. The subjective symp- toms all improved. Case '2: The pulse rate changed from SO to 72 and the blood-pressure from ISO to 135 millimeters in fifteen treatments. I'ric acid from .1 to 2 grams per liter and urea unchanged from Id grains per liter. Similar changes were produced in all \'2 cases, and in several which he had an opportunity to see some months after treatment the improvement had been permanent. A series of observations by Moutior and Challamel upon a large number of patients showed a reduction in blood-pressure of oO. 40. or .10 millimeters after the first treatment by the autoconduction cage, and of onlv 1"), 20. or oO millimeters after the first treatment by the autocondensation couch. To verify this advantage of the cage over the couch they were able to obtain an additional reduction of ;">, If). 20. or o5 millimeters by an application with the cage alter reduction by the 1 1 . Arch, d VI eetrieite medical e. No. !.">(), Sopt. I ">, I !H) 4, communication to the Medical Congress ;it (in-noble. "Arteriosclerosis treated !>y d'Arsonvali/ation." _'. . \reli. dVleetrieite ineilicale, I'eh. 1 ."> and Sept. 1 .">. I'.MI.'I. :>. " PsouiloniMiras- I henia with urterial liypeiMcu-ii >\\." Connnunieat ion to ttie Socicte niodirah 1 IN urr.. session ni April \'2. I'.MIO. 1. " Neurast henia. " ci minninieat ion to the Soejrie Medico-chinir<:icalo de Paris, session of Oct. 'JS, 1(101. ">. Zcit -clirin fiir Klektro- iherapie, vol. vii. No. L', I'.M)."). - (i. Arch, d 'elect ricil e iiHnlicale. Xo. K'rJ, Marcli 2.">. I'.M)."). ^'Comparison be"- i \veen autoconduction and autorondensat ion in arterial hypertension.' 1 1 7. Arch, il'rlortririte tnedicale. April _'.">. I" 11 - ">90 MEDICAL ELECTRICITY AND K(")NTGEN HAYS couch. Moutier recommends five or ten minutes for each application and that they should he given three 1 times a week. Neurasthenia with high arterial tension he calls "neurasthenia." The presence of this symptom calls for the application of high- frequency currents of comparatively low tension. The d'Arsonval autoconduction cage and autocondensation couch an* principally em- ployed (these have heen described on page ")}."> i, hut other means Fin. 3iG. -The d'Arsonvnl transformer with >in;ill .-ulcnoid. are also used. The patient may -imply hold 'two metal electrodes connected with the terminal of the small solenoid of a d'Arsonval apparatus or he may hold one metal electrode while the other electrode, which may he either metallic or a vacuum tuho. is ruhhed over the epigastrium and along the spine. Or two metallic plate 1 electrodes may he placed, one over the spine and the other over the epigastrium. (if. following the author's usual custom, the patient may sit upon a metal plate electrode, from which he is completely insulated hy a thin sheet of indurated fihor, and may rest his hack against a similarly insu- lated plale elect rode. Kadi electrode is connected with the corres- ponding extremity ol' the d'Arsonval small solenoid. All the different methods produce the same oscillating currents in the hody. either hy direct conduction or hy induction. The autoconduction cage has heen employed in Kurope, hut the other methods are more usual in :';;. Kxactly which method should he selected depends upon The nature ''I the case, especially upon whether some local effect is de-in-d, ;i- well as the effect of lowering the general hlood-pressuro. I' hi : let ion in arterial tension under flie application of d '. \rsonval- ixaTion i- ; ccon ; allied h\- a sensation oi warmth heginning in the hands ii ii'lurj: to the hodv and the lower e\t remit ies. Som- ha- -howii that a thermometer hdd in the hand registers an i.-eil . ; ii mperat ui'e. At the same time, there is an increased amplitude in the capillary pulse and diminished tension in the radial HIGH-FREQUENCY CURRENTS 591 current. The return of function in the nerve was generally expected to take place spontaneously if at all. and was thought to he only assisted by treatment. High-frequency currents produce so little muscular con- traction as not to be of any service in this way. They do. however, maintain and improve the nutrition in paralyzed muscles, and seem to have an effect upon the return of function in the nerve. The author's experience has been largely with cases of Infantile paralysis, and with cases of musculospiral paralysis from pressure and facial paralysis from exposure. In these cases the results have been successful. The application for paralysis is made locally by glass vacuum electrodes applied all over the affected muscles and over the spinal centers of the affected nerves. Wider observation will be required to determine the relative advantages of the high-frequency current and the galvanic and galvanofaradic currents. The vacuum electrode may be connected directly with one pole of an .r-ray coil or is connected with the d'Arson- val or Oudin apparatus. A current of about loO milliamperes should be used for about fifteen minutes three times a week. Among the cases of infantile paralysis may be mentioned one treated at St. Bartholo- mew's clinic. One poor little hand was crippled and about half the natural si/e, and the leg on that side was in the same condition. A few months' treatment with a vacuum electrode connected directly with one pole of an .r-ray coil brought the paralyzed arm and leg up to a size exceeding those of the normal limbs originally, and at the age of two and a half years the boy was strong and jolly. There remained an indefinable evidence of the previous trouble and the author does not know whether this has completely disanpeared or not. Cases of longer standing with deformities, such as talip.es equinus from contrac- tion of the muscles opposed to the paralyzed ones, of course, require mechanical and surgical treatment in addition to the application of elec- tricity, but the latter is a valuable adjunct. Parali/xix Aijitdnx (Parkinson's Disease}. Doumer and Maes 1 report a case very much benefited by atitoconduction for five minutes prac- tically every day for five weeks. The patient was an old man of seven! y- two with the classic symptoms. The arterial tension became normal and all symptoms disappeared. Ep /Vc/;*//. A combination of the .r-ray ami high-frequency currents has been used in the treatment of epilepsy, and the results reported by Branth- and Tracy" show that a certain amount of benefit is pro- duced. Tracy's figures show a percentage of tentative cures amounting to 2") per cent, in petit mal, 20 per cent, in .lacksonian epilepsy, and 12 per cent, in grand mal. In these cases bromids were also adminis- tered. In a disease as inveterate 1 as this cures must be substantiated by prolonged freedom from recurrence, but the treatment is worth while, even if the benefit does not prove permanent . An .r-ray tube with a high vacuum No. C> Benoist and a moderate strength of current is placed with its anticathode 10 inches from the patient's head and al- lowed to shine for five or ten minutes (1 or 2 Ilolzknecht units). After this high-frequency currents from a vacuum electrode connected either with the d'Arsonval transformer or the Oudin resonator are applied 1 Jour, do Physiothc'rapie, November !.">, 1905. 2 Now York Medical Journal, 1901. 3 Ibid., March 1, 1904. ~>')2 MKDICAL KLKCTKKITY AM) KOVHiKN HAYS over the brain for ten minutes and along the spine for live minutes. A current of 1")0 milliamperes is used. This treatment should be given three times a week, but the .r-ray cannot be continued very long be- cau-e ot the likelihood of causing permanent alopecia.' ("hurt a. This is a disease in which the general tome effect ot high- frequency currents is peculiarly beneficial, and the author. has treated many cas< - \\ it h uniform success. The application has been made by a vacuum electrode connected in some cases with vibratory currents from one pole of an .r-rav coil, and in ot her case- with high-frequency cur- rent.- from the d'Arsonval transformer or the ( hidin resonator. The results have been equally good. A current of ].">() milliamperes is applied for fifteen minutes along the spine and over the limbs, and while po\\- der i- used to enable t he electrode to glide nicely over the surface, a certain amount of -park-effect is desirable. This should not be sufficient to be disagreeable or to bring out little red ooints upon the skin. The treatments should be given t hree times a week. Improvement i.- rapid and. uniform. This method mav be recommended in any case, but the a ithor does not mean to say that no other form oi electricity would 1 ii a- g< iod m -i line cast -s. /,''" Atii.fin . The author has t reat ed cases of this disease by a combination of the .r-ray and high-frequency currents. Marked improvement ha- resulted, so that the patient's friend- have stopped him on the -treet and asked him what treatment he was receiving; but the]' a cure can be effected in such cases remains to be seen. The improvement was especially noticeable in regard to the gait and the lightning pain-. The girdle sensation persisted, bin the lack of coordi- nation was benefited, and in one case seen two years alter the cessa- tion of treatment, the patient was able to perlorm the delicate movements required in shaving. The technic in these cases has been the application of .r-ra vs. \d. i> or 7 Renoi-t . over t he -pine at the lower level of 'he scapula twice a week, of such a duration and intensity as will produce only the slightest redness of the skin after three weeks' ise. then discontinuing the use of the ./--ray lor three weeks and taking again in the same way. Vibratory currents were applied from a ode connected directly with one pole (it the .r-ray coil, the current being about h">0 milliamperes. and some little spark-effect isi-d. This current was applied to the lower extremities and a lot m the -pine for fift een mm ut es t hree t lines a week (on the same days as the .r-ray. and one extra day each week-. The only improvements In tin in-atme-nt of I'pilep.-y it is of (lie utmost importance to search for and " ovi ny i-xeii \\ry ot having I >een wounded in the Spanish \Yar. j : ' ; I'-nl epilept ifunii ci mvulsii m- or chorea major since then. ioe,i every three ueek- Mini u-ually l'ollo\\i-d -otne -lii_dit injurv. liieycle Aiini her t ime In- cauirht hi- fintrcr in a c-ofT-wlu'cl I i nir t In convul-ioTi- he made friirhl I il noi-e- ;; in | foamed at tin- -in four t n -is LT 1 " "1 nn 'ti lo hold him. \\ hili- it t ook t he doct or the influence of niorphin and chloroform After tin- ti'co^ni/e iii- friend-. \< M more often [,, ,jj,| ,,,,( \\ake up d lieen ireati'd un-ucce--fully I >y mixed liromid- and in it riiein I imina! ii'i r\ t i-ht prepuce, iliundant \\hite uati-ry di-charir<-. the dan- l>eini: fairly Iceratien- \ r-ircumci-ion i fleeted MII in-tant and ; . [,.-n- r ..,- HIGH-FREQUENCY CURRENTS 593 that the author would surest in this technic would he the use of the Oudiii resotuitor and the application of a high-frequency current of '_'(>() milliamperes without much spark-effect, keeping the glass electrode 111 motion; and the application of a quantity oi the .r-ray actually measured, as by I lol/knecht 's chromoradiometer, and amounting to a little less than 111. twice a week. The anticathode of the tube is about 1 1 inches from the skin, no locali/er being used. In inexperienced hands the .r-ray should not be applied over the spine. It is not at all probable that pathologic changes can be produced in the spinal cord by rays which do not injure the skin, but at the same time it would be unwise for one who was not sure of the strength of ray produced by his apparatus to take the risk. .Y< '//// /'.s obtained excellent results from the direct application of the vacuum electrode to the point of exit of the nerve and all over the painful area. These results have ensued whether there was just a single glass vacuum electrode connected directlv with one pole of .r-ray coil, o; with the ( hidin resonator (Fig. 377), or whether the d'Arsonval transformer was used. \Yith the last-named apparatus the patient holds a metal- lic electrode in one hand while the glass elect rode from the other pole of the apparatus is applied to the affected region. In any case the skin should be powdered and a current of '_'()() milliamperes applied during fifteen minutes for sciatica, or 1">I) milliampere.- during six minutes for trigeminal neuralgia. This should be given every other day. Two or three weeks usually see- the milder cases cured, while those of long standing may take two or three months. The strength of current prescribed is that which actuallv passes through the glass 594 MEDICAL ELECTRICITY AND RONTGEN RAYS vacuum electrode. There should be but a slight spark-effect. The pain-relieving property of hitrh-frequency currents and their tendency to relax spasm, together \vith the fact that they do not cause muscular contraction or any di.-amveable sensation, make them the method of MI 'i:]>lvniu higli-frfijur hese cases. An extreme c Kx**'^<*mimmm higli-frfijurnry CHrn.-iit.- in triuu'ial tx-uraljria. xtreme case is reported bv Somerv eakness. and anesthesia impi'oved choice in tese cases. An extreme case s re in \\!i!''h alaxia. muscular weakness. and ane much under t rcat mi-nl by hi^h-frequency bewail .'.!;. numbner-s and weaknes< in one le t \venty-one years old. to resign his position a,- quence oi e\ i n )sii re in a 1'aiiisionn the conditi ;ind In- \va.- confined to \><-<\ \\nii motor and se '' ases. An extreme case s reporte bv Somerville, 1 muscular weakness. and anesthesia impi'oved verv at mi-nl by hi^h-frequency currents. The trouble ner-s and weaknes< in one leu, causing the patient, old. to resign his position a,- a postman. In conse- re in a 1'aiiisionn the condition became much worse ned to \><-<\ \\nii motor and sensory paralv.-is of both . as well as both lejrs. 'I'lie symptoms did not indi- taxia. but rather peripheral neuritis. 'I'hei-e w;is no HIGH-FREQUENCY CURRENTS 595 when the application is made locally by the vacuum electrode. The effect of the autoconduction cage or the autocondonsation couch is systemic and, of course, will be suitable in some cases, while it is con- traindicatod in others. The local benefit would not be obtained if the application affected the general nervous system unfavorably. The local application hardly over fails to have a favorable influence on the general condition, and while not always successful, there is no class of cases in which it is especially likely to fail. The high-frequency application, known as thormopenetration (page 031) has often given good results in the author's practice. It is especially suitable for eases with one or more definite 1 painful areas; while the other cases with general pain and weakness in an entire limb are treated by the slow sinusoidal current and four-cell bath. X'eiii'dlt/id. Bipolar effluviation from double resonators or double spirals may be followed by sparks from a nionopoiar Oudin resonator. A method which has succeeded well in the author's hands has been bv a glass vacuum electrode connected with a nionopoiar Oudin resonator. The voltage and amperage have to be carefully studied for each case. X fiirdli/id of the Lumbar l*lexux. Heavy galvanic currents may bo used. High-frequency currents may be applied from the d'Arsonval transformer. The patient holds a metallic electrode while the wire from the other terminal leads to a plate electrode covered with wet cotton which is applied to the lumbar region. Or the glass vacuum electrode may be substituted for 1 he moistened plate electrode. Chrotiir Sfinfir Xeto'dlfiid.Thi* is bv far the best application for these cases. Suitable methods of application are: I. Autocondonsation for about five minutes, the patient sitting upon the insulating indurated fiber covering a sheet of metal while his back rests against another. Tin's the author follows by a mild or strong application of a glass vacuum electrode from the( luilleminol s| nral along the course of the sciatic nerve and its branches. Whether to redden the skin or not is a question to be derided in each individual case, but generally mild applications are the more beneficial. Five minutes is about the propel' duration. Vibratory massage along the course of the nerve in the thigh is a desirable addition in some cases. '2. A method recommended by Albert \\eill employs first a bipolar effluve and then nionopoiar sparks. A larire plate electrode from the pole of one of the resonators or spirals is directly in contact with the lumbar region, and a brush electrode or efiluve is held near successive parts of the painful region until the latter is all reddened. This anes- thetizes the skin to a certain extent and prevents pain from the second part of the treatment. A series of large white nionopoiar sparks are applied along the nerve. These turn the skin white, but it soon becomes vividly congested and the sciatic pain is immediately relieved and the patient able to walk better than he could. Some ot the improvement persists until the next treatment. Applications are made at first every day, then three times a week, and a complete cure is to be expect 0(1. Si'intir Xcurititt. The d'Arsonval apparatus is used, giving a bipo- lar high-frequency but comparatively low-tension discharge. One wire passes to a sheet of lead or tin applied directly to the lumbar region and tlie other to a similar electrode fastened to the le^ below the calf. nib MEDICAL ELECTRICITY AND RONTGEN RAYS The milliamperemeter should indicate a current of 300 or 400 or more ma. and the application should last about ten minutes. Bordier recom- mends this met hod very .-! roiigly. The mildest application of a glass vacuum electrode connected with a monopolar (luilleminot .-piral and with an adjustmenl of appara- tu- i:ivim: a discharge of l"(l ma. with scarcelv anv spark-effect has given wonderful re.-ult- ill the hands of the author. One case of two years' standing was cured in seven application.- and remain.- well now. three years later. I n*uniniti.- \\hen this condition occurs as a >ymptom of any dis- ea-e in which high-frequency currents are indicated, it is usually cured \iy -uch treatment. Tliis happened in a case of gast ric atony treated liy the author. The application was by a vacuum electrode connected with the ( hidin resonator, the electrode being passed over the abdomen and along the upper |iart of the dorsal region of the spine. But where insomnia is the chief symptom and almost constitutes a disease it is not always best to treat it by high-frequency currents. In an}' case the method of application must be carefully studied. Somerville, 1 using 'aiffe's transformer and high-frequency apparatus with MM) to 1000 milliamperes passing through the autocondensation couch, has succeeded with such cases after fifteen to thirty treatments. Drowsiness is not always one of the results of high-frequency currents and improvement in regard to sleeplessness comes as the result of a number of treatments. The application does not. like hypnotic drugs, induce an unnatural sleep. but rests and invigorates the patient, and >o brings about natural sleep. Too lonu or too strong an application of high-frequency currents i- liable to cause sleeplessness by its effect upon the circulation in the brain. The application of a glass vacuum electrode, with a current of !.")() milliamperes, to the back of the neck and head for about five minutes will almost always have a reflex soothing effect. This will tend to produce sleep through an effect on the nervous system. I'niniu! ( 'onilitioii* .\<>f /if \irri Orir/in.- I'll iiritir JHII'HX are well treated bv the gla.-s electrode with L'lid milliamperes from the Oudin resonator for t en minute.- every ot her day. I'liinfiil /fnf-ftxil is one of the condition- m which the application ' tin vacuum electrode i- of the tireatest benefit. A current of b~>0 milhampere- i- applied for fifteen minutes to the toot and leg three time- a week. The apparatus may be either the d'. \r-onval t rails- or t he ( ludiii re-onat or or the vacuum elect rode may be connected directly ui'h one pole of an r-ray coil. I'owiler should be used and Dill the -lightest -park-effect allowed. There may be some advan- :. i.-iiiL: the d"Arson\"al transformer and having I he patient hold the ;.' metallic electrode. In the author's cases llu- has seemed a hn]e more ionic effect than the unipolar ajjplication. it plate- are, of course, a necessity in these cases. When the eaknes.-, as shou 11 b\' pain and the characteristic the combined electric treatment and mechanic support: verv promptly, and eventually effect a complete li'-i - ; ' di.-ease i- of lom: duration and there is deformity - iriiieal operation ma\' be nece.-c^U'\ before electricity is HIGH-FKKQtENCY CURRENTS 597 High-frequency Currents in the Treatment of Cicatricial and Fibrous Conditions. Dupuytrcn's Contraction. This is a condition which occurs in middle or advanced life and is due to u contraction of the palmar fascia, with adhesions to one or more of the flexor tendons and to the skin. It is evident on looking at the hand, and especially so when an attempt is made to fully flex or extend the finders. Herd- man 1 has treated these cases successfully by high-frequency currents and calls attention to the fact that the trouble is not a contraction of the tendon, for it is the proximal phalanx of the finder that is flexed, and no position of the hand will permit it to be extended. Then, again, con- traction of the tendon would not cause the prominence of the tendon which is seen in these cases. A rheumatic or gouty tendency is usually found in such cases and sometimes neuritis of the ulnar nerve. The local condition is a chronic inflammatory process due to the systemic state, and bearing no distinct relation to the use which may be made of the hand in the patient's daily life. The role of high-frequency cur- rents in the treatment is to cure the constitutional tendency. A suitable application is made by means of the autoconduction cage or the auto- condensation couch. The author has more frequently used the vacuum electrode, applying a current of 150 to 200 over about a quarter of the surface of the body during fifteen minutes. The surface is powdered and the electrode kept in motion. The use of the tissue oscillator over the hips and lower part of the back for a couple of minutes is a most desirable addition. The galvanic current with negative electrolysis, using only a few milliamperes, has cured the local condition. High-frequency Currents in the Treatment of Certain Con- stitutioual Diseases. Diabetes. Static electricity and high-frequency currents are both of value in diabetes, but should probably be lim- ited to cases in which metabolism is slowed. They may do harm in cases where there is exaggerated denutrition and the examination of the urine shows a nitrogenous coefficient higher than the normal. DeRenzi and others have seen the return of sugar caused by high- frequency applications in such cases. Conflicting reports have appeared in regard to the efficacy of the treatment in this disease. D'Arsonval reported 2 successful cases as long ago as 1S9(>. Both feet rested in a bath to which one electrode went: and the other electrode, a forked one. was held by both hands. Apostoli, at the Twelfth International Medical Congress, reported success in over 500 cases. Autoconduction cages or autocondensation couches were used and the average number of treatments was twenty- five. Following Apostoli, several of his pupils and assistants have re- ported successful results. Some others who have succeeded with it are Williams.- Allen; 1 and the present author. On the other hand, Boedeker, Colin. Loewy, Douiner,' 1 and more recently Halfon/' have reported that high-frequency currents produced no reduction in the amount of urine, r'reund i" Radiotherapy") does not express an opinion. The author knows that in certain cases the sugar will not dis- appear, but believes that even in these cases the general strength 1 Archives of Physiologic Therapy. l-Vl>ruary, MM)."). - Iliph-frcquoncy Currents m the Treatment oi Some Diseases. 3 Radiotherapy, etc. ' Annal. d'elertrobiolotrie. vol. iii. '^ 11 pro^resso medico. No. :}, 1903. O9S MEDICAL ELECTRICITY AND RONTGEN" RAYS I and the cutaneous and other disagreeable symptoms are so much benefited as to make high-frequency currents a necessary part of the treatment of every case. That there are manv other cases in which the sugar disappears in a most wonderful manner is equally certain. It ha> not been the author's habit to ask for a discontinuance of med- icinal treatment, and so his own cases can hardly be cited as absolute proof that the electric treatment alone would have been effective. Hut what he is able to say is that cases which have been doing very badlv under medicinal treatment alone have done very well under the combined medicinal and electric treatment. One such case was that of a lady about forty years old who was passing about .l(i ounces of urine daily, and this contained 10 per cent, of suirar. She had dis- tressing abdominal symptoms consisting mostlv of pain and diarrhea. Three weeks' combined treatment by medicines and the .r-ray and high-frequency currents reduced the amount of urine to ")! ounces a day and the sugar to less than 1 per cent., and the patient left for her home in I'ortn Uico feeling entirely well Another similar case was that of a gentleman of fifty-five who had suffered from asthma and dyspnea for a month or two. and progressive and terrible emaciation and loss of strength. He had lost l2~) pounds in six weeks and the urine if)1 ounces a day) contained 10 per cent, of sugar, or 127-11 grains per diem. He was so weak that his wife had to dre-s him. and lie was apparently hurrving toward a fatal termination. In his case also the x-ray was used in conjunction with high-frequency currents, and the administration of arsenical preparations was continued. During the next two and a half weeks there was practically no loss of weight only 4 pounds and by the end of that time a change for the better set in. He began to gain weight and strength, and it was evident that his life was saved. After one or two weeks more of treatment by high-frequency currents without the .r-ray he was again placed in the hands of his regular physician for treatment by static electricity, and made a irood recovery. As indicated above, the French operators have generally made use of the methods of general electrification which employ the autocon- duction caire or the autocondensat ion couch, and if either of these are used a current of at least .100 to 800 milhamperes should be applied; and -hould last ih'teen or twenty minutes and be repeated every The author's own preference is for the .r-ray. rays \o. 5 . applied over the abdomen twice a week with the anticathode ies from the skin and the applications long and strong enough luce Mime tanning of the skin in three weeks, but no redness. half the normal exposure described on p. L 1 .10 is suitable for The vibratory currents in both ot the foregoing cases were 1 vacuum electrode connected with one pole of ;tn .r-ray 'iirreni of about 1200 milliamperes was applied over the nd down the -pine (or about twenty minutes three The skin must be powdered to allow the electrode to urtace \\nfioiit sparking. The Oudin resona- lent when as heavv a current as this is desired equally .u'ood results. Kven in cases where d I he percentage o| sugar are not reduced the HIGH-FREQUENCY CURRENTS 599 bly the disease is actually cured or whether the patient is only made practically well. Some preparation of arsenic seems to be the medic- inal agent for use in conjunct ion wit h the electric t real men t. Hhi'unititisni. Jones' considers this treatment contraindicated in acute rheumatism and says that it gives good results in chrome rh< u- matism. but requires a large number of treatments, twenty-five to thiriv at least, and sometimes two or three hundred (Apostoli and Laqucrriere). There is no difference of opinion in regard to its being of value in chronic rheumatism, but some operators think that it has not yet been shown to possess any advantages over other forms of electricity, such as electric baths and static electricity. The conveni- ence of application and the ease and certainty with which the appli- cation can be regulated make this the ideal method of treatment if it be shown to be effective. Here, as in other constitutional disorders, many operators employ autocondensat ion or autoconduct ion, but the author finds the application of the glass vacuum electrode to the affected joints or other localities and then over the abdomen and along the spine or in some other way to apply it to a large part of the body very effective. The cases which have been treated in this way have been referred by their family physicians after medicines, massage, and baths had failed to give relief. The results are perma- nent, not mere temporary stimulation or analgesia, and a healthy action of the tissue cells throughout the body is inaugurated which results in continued improvement after the treatment is all over. In many cases there will be wonderful improvement within a few hours after the first treatment, and this improved level is maintained but not materially surpassed for about three weeks. At the end of this time a gradual and uniform improvement begins which continues as long as the treatment is kept up and for some time afterward, so that often the patient feels better a year after the treatment was stopped than he did immediately afterward. Some of the cases which have been successfully treated have had pain and enlargement and stiffness of several of the large joints and of some of the smaller ones, but without serous effusion. The symptoms have entirely disappeared except that perhaps some one finger joint may remain a little enlarged, though painless. Cases with rheumatic synovitis of almost every joint in the body and of many years' duration may be very much benefited, although in some of these a cure is not to be hoped for. The benefit is shown by the prevention of the acute exacerbations which every change of weather and certain other conditions bring on. There is also a return of the joints to about the normal appearance and the deposits about the sheaths of nerves and in the region of the joints is removed or diminished. The patient becomes able to sleep and his general con- dition improves very much. From being sick in bed from a tenth to a quarter of the time, such a patient may often be transformed into a condition of apparent robust health. An expert examination may show, however, that the synovial membrane of nearly evorv joint is still thickened, and an occupation involving prolonged exposure to cold and wet would be liable to bring on an acute exacerbation. There are many cases which other means have failed to cure and which high-frequency currents will cure either completely or practi- 000 MEDICAL ELECTRICITY AND RONTGEN RAYS cally. Other cases must be classed as incurable, though the}' mny be very much relieved by t his t real men t. The author's method of treatment has been published 1 and consists in the application of vacuum electrodes from the d \\rsonval trans- former or Oudin resonator to the affected joints and to a considerable portion of the bodv: tor instance, over the abdomen and along the spine. The current is about L'OO milliamperes and the application requires from one-quarter to one-half hour. With this is applied mechanic vibration along the spine and perhaps over the abdomen. In occasional cases the .r-rav is applied to remove some obstinate and painful swelling about one particular joint. The high-frequency current has a strength of about L'OO milliamperes; and severe cases with several large joints to be treated require an application of about one-half hour. A certain amount of spark-effect is desirable over the joints, but this should be only the fine crackling that comes when a < onvex electrode is in good contact with only a portion of its surface 1 touching the skin. The skin should be powdered and the electrode kept in motion. Treatment three times a week is best, but twice or even once a week will often accomplish a cure, though a longer time may be required. The result is due partly to a local stimulant and counterirritant effect and partly to a const it utional effect . By t he lat ter the defect ive processes of met- abolism are corrected. Nitrogenous substances, for example, leave the bodv completely oxidized as urea, instead of partly oxidized as uric acid. Whether or not it is correct to regard uric acid as the cause of rheuma- tism, it seems to be a fact that it is present in the tissues and excreta to an abnormal extent in 1 hese cases, and t hat measures which result in its diminution have a curative effect upon the disease. Williams 2 observed in one case that the proportion of uric acid to urea in the urine was at first I to ">] and gradually changed to 1 to 70. then gradually changed all t lie way back to the normal ratio of 1 to ; ; >.">. The change accompanied the recoverv of the patient from a case of chronic rheumatism. The symptoms had been "rheumatic fever at twenty-six years; now at forty-eight there are dyspepsia, rheumatic pains all over, but especially in the lumbar region, and history of several big-t oe-jomt attacks. Small joints all more or less enlarged. Appetite nil and sleep bad." He was treated bv aut ocondensat ion ten minutes dailv with a current of :;.">() milliamperes; and in seven weeks made a complete recovery and Drained (> \ pounds in weight . In 'he majority of cases treated there is no special change in the daily excretion of urea, and very otten the examination of the urine lie rheumat ism. al Record " are with a family history in her s case a t t hirt v-nme) , paralvsis of the throat, and apoplexy, on male paternal ancestors bemjj; laru'e men. in 10M.X F. His HIGH-FKKQUENCY CURRENTS 001 present trouble dated from nti attack of lumbago two years afro. He was not sick in bed, but any movement was very painful in the morning, with gradual improvement through the day. The symptoms disappeared in two months. Status pnesens: (J feet 4 inches in height, weight 17") pounds; some flat-foot and consequent unusual breadth to the ball of the foot. The right great toe joint is swollen and stiff and then- is a gouty pain in it, especially on awakening. The middle toe; of the right foot has a sensation as of slipping out of joint. Then 1 is a rheumatic pain in the right hand. These symptoms have remained so aggra- vated, in spite of medicinal treatment, as to threaten to incapacitate him for business. Shortly after beginning treatment he had a fall which produced a severe ecchymosis of the left thigh and stiffness of the knees and an added rheumatic pain in the left hand. The treat- ment consisted in the application of high-frequency currents and vibratory massage according to the author's uric-acid tcchnic and the administration of 10 grains of salophen three times a day; the avoid- ance of tea, coffee, and tobacco, and the application of flat-foot plates. At the end of a month the gouty pain in the right great toe had almost disappeared; only a trace remained of the rheumatic pain in the right hand, and the rheumatic pain in the left hand brought on by the fall had been reduced three-fourths. After another two weeks' treatment the patient reported himself so well in every way that it seemed proper to discontinue the treatment. The very marked effect of the first treatment was produced before he had begun taking salophen, but the latter is a valuable adjunct in these cases. The patient came a year later to report his condition, which was excellent. This patient and the next one were in private practice and were cultivated people, but accustomed to simple rather than luxurious living. Another patient was a lady of fifty-four, weighing 2S7 pounds, and with a family history of rheumatic gout, making them chair invalids for years. Personally she had always been careful about diet, but had gradually become more and more affected by a rheumatic or gouty condition which, in spite of medical treatment, had finally crippled her. For some time previously she had not been able to walk more than two or three blocks and on coming to a curbstone would hesitate for some time before attempting to step up those 2 or 3 inches. The knees were badly swollen, the joints of both feet were stiff and swollen, as was also the middle finger of the light hand. The day following the first treatment she was walking any number of blocks, going up and down stall's, and "feeling like a bird." 'Phis was before she had begun taking salophen. The original brilliant improvement remained, but was not surpassed until after two or three weeks of treatment applied two or three times a week. Then a stead}' advance began. The local- ities exhibiting the slowest progress were one knee, which she had strained some time previously, and the middle linger of the right hand. '[ o these several applications of the .r-ray were made. For this an s-inch coil was used with a Caldwell-Simon interrupter and a M filler heavy target tube which was encased in a localixing shield. The holes 111 the interrupter were small and gave a primary current of 4 amperes with rapid interruptions, rays \o. I Henoist. The anticathode was at a distance of 9 inches from the skin with exposures for two min- t)()2 MKDICAL ELKCTKICITY AND H(")NT(;EN RAYS ute- twice a week. The beneficial effect was immediately evidenced by prompt improvement in the knee and finder. A rilirtitnr u.-ed in these cases was made by Wappler. of Xew ^ ork, it has a ^.-hor.-e-power motor, a flexible shaft, and a ball extrem- ity in which an exceiitric weight revolves. The ball is applied lat- erally so as to produce 1 he effect of pressure and release with short rapid strokes, but without loss of contact. The speed and the length of the stroke i.- regulated for each case. The effect is to stimulate any nerve, it' il is applied lightly and fora ,-hort time; and to depress or produce a sedative effect on ativ nerve over which it is applied with heavy pressure and for a lom_r time. The effect of vibration in rheu- mati.-m i- partK' one of stimulation of the general metabolism, and partly also an effect upon the trophic center.- in the spine, which influence all the tissues of the different joints ihev supplv. Kven without electric or other special devices the author has for many year- prescribed m.i--a'_re ot the posterior roots of the spinal nerves for cases oi rheumatism of the knee, for example, which did not vield tc medicine- and local applications. This was verv successful and mad-- it ea-\ tor him to believe some ot the claim.- of osteopathy when ..:- promulgated. The patient -.'.a- under treatment by hmh-t re<|iiencv currents and rnerliainc vibration for four month-, and at the end of that time -'<:;; 1 i el), 'hou'jh ihere remained a little enlargement of tin joint "i the middle finder. Manx month- afterward she reported health and siren;:! h, and thinks that the ^reate.-t benelii came 'I'eainient \\"a- finished. At the present time, . h' more eut husia-t ic than ever about it. The treat- HIGH-FREQUENCY CURRENTS 603 ment produces a permanent change in the system, not a mere temporary stimulation. ()l>cxitij. Arthritic and gouty patients suffering from obesity are benefited by autoconduction or autoeondensation or by the general ap- plication of a glass vacuum electrode while the patient holds a metallic electrode connected with the other pole of the d'Arsonval Iran-former. Then 1 is sufficient evidence that autoeondensation or auto- conduction will reduce the size of fat people by stimulating the processes of metabolism. It is uncertain, however, whether a reduction in weight may be regu- larly expected, or only a certain reduction in bulk. Quite exten- sive applications with the vacuum electrode proved only moderately successful in the case of a patient who weighed 210 pounds, though only 5 feet 4 inches in height, and who had the marked som- nolence which would naturally be expected. He would go to sleep while reading the newspaper, or on the street car on his way to be treated, or in the reception room, and invariably upon the operating table. He lost G pounds in six weeks' treatment and im- proved materially in regard to the drowsiness. It seems probable that the treatment by high-fre- quency currents is not the first choice in cases of obesity unless they present some for it in addition to mere weight. A more effective method of treatment is by mechanic means, and the best apparatus is a tixsuc oscillator. This has a powerful electric motor, the speed of which is regulated by a rheostat. A heavy iron pillar supports a revolving shaft and the pulleys on the motor and shaft may be so adjusted as to give from .'$00 to 2 K)0 revolutions a minute. Close to each end of the shaft is fastened a pin which may be adjusted more or less excent rically. Two handlebars are thus given a back-and-forth motion, the length of stroke being set at from zero to an inch or more. For certain purposes the handles mav be held in the two hands and pulled while the machine is put in very moderate motion. An acute attack of stiff neck, or of myalgia about the shoulder, is relieved bv three or four minutes of this application. For most [imposes a belt is attached to the two handlebars and passed around the patient, who steadies himself by the handles and lean- all his weight against the belt. For obesity the belt is applied over the buttocks for five minutes, the patient facing the machine: then over the abdomen and over the shoulders. The stroke should be about \ inch and must be exact Iv even on both sides. The adjustment is special indication 604 MEDICAL ELECTRICITY AND RONTGEN RAYS such that one side pulls as the other relaxes. If the proper adjust- ment be made and a suitable speed t , or hi p.- n ' i] by this mean.- ju.-t as by the more natural means of outdoor e\<-rcjv. I In I < >. i i i /it/*//' in ( /'n'-uiii/ < '.- In ^out. rheumatism, or in .:.':-. or ' 'a the many conditions likely to occur in men and n who cut und drink an abundance ol rich lood and wines, and v/ho. while |" loin.:; plenty of menial work, ^ei very little physi- cal ev-rci-1-. , nt i-- i,t' the L r reate.-t value. It nives the neces- HIGH-FREQUENCY CURRENTS 605 sary stimulus tu digestion and circulation, and is a valuable adjunct to electric treatment. (lout. High-frequency currents applied by autoconduction or autocondensation or, in the author's practice, especially by vacuum electrodes give excellent results in this disease. Most writer.- do not recommend this treatment for acute attacks, and some even say that it may precipitate an acute attack. The author's experience leads him to believe, however, lliat the treatment affords relief at any stage of the disease and that any case may be treated with a view to producing a cure after a complete course of treatment. If the auto- conduction cage or the autocondensation couch is used, the current should be 500 milliamperes or more, and the application should last fifteen minutes and be given three times a week. If the vacuum elec- trodes are used they should be exhausted to the degree which will give the richest lilac-colored glow and the greatest amount of ultraviolet radiation, as detected by the fluorescence caused in a piece of Willemite. The current should be about 200 milliamperes from either the d'Arson- val transformer or the Oudin resonator and should be applied over the whole of the affected limb for fifteen minutes, keeping the electrode in motion and avoiding spark-effect. The current should be reduced to 150 milliamperes over any ec/ematous areas and over acutely inflamed joints. The treatment should be applied three times a week. The patient ought to feel entirely well in six weeks, but to consider the treatment finished, two or three courses of treatment lasting six weeks each should be ii'iven separated by intervals of about two weeks. The tissue oscillator is applied with the belt around the hips and the patient facing the machine. A mild application is made for two or three minutes. In this disease. as in rheumatism, the effect of the first Treatment is often wonderful. The author has had patients who expressed doubt as to its being due to the treatment at all. They said it must have been a coincidence, but the subsequent course of events convinced them that it was the result of the electric applications. After the first treatment the im- provement is no longer by jumps, but is gradual and uniform, and is much more rapid than in rheumatism. The same vacuum electrodes completely heal the chronic or subacute ecxema which is present in so many of these cases. This is accomplished in the first few weeks. ('.only deposits about different joints are often removable by the high-frequency application called thermopenetration (page 031). .1. \V. Torbett 1 treats high blood-pres>ure (above 150) without a trace of sclerosis by hot blanket pack, autocondensation, or electric- light bath cabinet, both followed by alternating hot and cold shower, cold mitten rub, or Scotch douche carefully iriven. Arteriosclerosis. Every case calls for an .r-ray examination of all the teeth. The disease is often caused by dental infection and certainly will not yield to electric treatment until the infection is discovered and cured. The application of high-frequency currents, especially by the autoconduction cage, has a marked effect in reducing functional arterial hypertension. This effect will be described in greater detail in the paragraph upon neurasthenia with high arterial tension, and its suc- cessful employment in that disease has led to the use of this treatment in arteriosclerosis. In the early stage- of this disease the high arterial 1 AnuT. Jour. Ekvtrothcrupy and Hailiolo^v, vol. xxxvi. No. 1, January. l*Mv ()()() MEDICAL ELECTRICITY AND RONTUEN HAYS tension is due to vasomotor spasm caused by the same auto-intoxication which, acting through many years, is likely to cause structural changes in the walls of vessels and in every organ of the body. The auto- intoxication alluded to is often the effect of a sedentary life, with or without the influence of alcohol, and is especially the result of mental strain in business or professional life. It develops during middle or late life, and is a condition in which irritant substances, analogous to those in uremia, circulate in the blood and produce the functional and. finally, the increasing structural changes referred to. Many of the ailment- of later life rheumatic, hepatic, gastric, and nervous are the natural results of arteriosclerosis. In the early stages this disease can probably be cured, and one of the best methods of treatment is by high-frequency currents. They not only promptly reduce the blood-pressure but al-o cure the condition of defective metabolism and elimination which is the cause of the trouble. During the treatment the patient may be completely clothed as he sits inside the large sole- noid, called the autoconduct ion cage, or lies upon the insulated cushion ot the autocondensation couch. Hither apparatus is connected with a d'. \rsonval lu'uh-frequency apparatus actuated by an .r-ray coil, a trans- former, oi' by a powerful static machine. A current of ">(!() milliainperes or more passes through the cage or the couch, the patient, with the cage, not being in direct connection with the apparatus at all. but receiving an electric induction. The electric effect upon the patient is analogous to the induction of a powerful current in a secondary coil bv the passage of a current through a primary coil with which it is nowhere in contact and from which, in fact, it i- most carefully insulated. The applications la-t fifteen minutes and should be given every other day for about three weeks. In an early staue of arteriosclerosis each treatment may be fol- lowed by a fall in arterial pressure amounting to 2(1 or more millimeters of mercury. Before the next treatment the pressure rises ana in, but not to its original level, and gradually the normal level is r< ached and maintained. In advanced eases of arteriosclerosis this treatment is al-=d to be recommended, and the author's experience with it has in- cluded ca-es in which -Mine one effect such a- rheumatism, neuras- '. embnhis. or hcmianopsia- has required treatment. Hlectric- hnht baths also li'ive excellent results in arteriosclerosis. Autocondensation with a thick dielectric and small amperage are considered by \V. T. Johnson' to give better therapeutic effects. lie te- Dr. Mat hew Steel's report of a fall in blood-pressure of 4 to 10 . and an increase in pulse-rate of 2 to S in a normal man, and an in- crease ,,f :;iil) c.e, in the volume of urine and an increase of .") or 10 grams in the daily urinary solids. And the autocondensation with a thin dii > ctrie. while producing a sensation of warmth and also excessive per- s pi rat ion, reduces the volume' of urine, increase- t he urinary solids about 2 irram-, and lia- little effect upon the blood-pressure. ' // in 'in. nn. A. L. ( lordon,- treats early cases by diathermy I'd i-u-hion on a couch and KM) to ")()() ma. for fifteen or twenty and later every other day. Inactivity of the liver is t he static wave current . larne metal elect rode to lower mar- : a- -iron" a current a- patient \vill take for fifteen or '. r'.. M. -1 .1 n ml K:nli<>loiry. vol. \\xvi. X<,. 1. .I;iiiu:irv. 191S, HIGH-FREQUENCY (TRKKNT.S 607 twenty minutes; or by the slow sinusoidal current with one lar0 milliamperes, although the "French writer- use the effiuve with some direct sparks. In either way a revulsive and tonic effect is obtained which would certainly be of benefit in these oases. Tuberculosis is certainly susceptible of wonderful benefit by hiirh- frequency currents, but as with every other form of treatment, some mercury vapor lijrht, and mali-frcqucncy currents. eases iret only moderately well and eventually die of the disease. Other cases apparently net entirely well and may or may not have a return of the trouble at some future time. And in these cases who can say just what role the treatment has played in the process of recovery? The author'.- own technic in these cases include- the use of t he .r-ray and t he mercury vapor electric ligh.1 besides the hi amperes of pri- mary current were used, and care was taken To have a good contact and avoid a spark-effect. The result was extremely encouraging. In t hree weeks her voice became good enough to Talk over the telephone and the ex pectoral ion ceased. In t hree months t he t hroat specialist reported that nothing remained of the ulcer, but in its place there was a white >i ciratrix. She was able to eat everything and had gained -1 or "> eight. 1 his was the condition of things when the progress a-e was reported at a meetiim ot the Medical Association of New York. March. Idol. She continued to '.Mil. when the treatment was stopped on account ) u rim: the following winter t here was a gradual ion. but she did not again conn- under .r-rav did 1 >et ter while under i it herwise and in ml it n cotit mued. 1 >a rnu n i 1 bv the use oi li i'^h-t rei ii;ency currents from pa rt of the t i eat meni consist - i L; chair or couch \\hich is m circuit ion i- made with the patient -cnl >es the effect s as an imme- AuL'U-t. I'tK.'i. HKJH-FRKQUKXCY CURRENTS 00'.) diate rise of temperature of at least 1 I-', during the time of treatment and a sense of exhilarat ion last ing for twenty-four to sevent v-t \vo hours. He uses an unusally po\vei1'ul high-frequency apparatus consisting oi' very large beyden jars and an Oudin resonatoi 1 . \'2 inches in diameter ami '.] feet high, and regularly applies from 2000 to :>000 milliamperes. Some ot his cases were apparently cured. The treatment \vas carried on in connection with tent-life in Los Angeles, California. High-frequency Currents in Diseases of the Larynx. -Tnlx-r- cidoxix of the lari/n.r is a disease in which high-frequency currents and the .r-ray afford relief with a possibility of cure. The method of appli- cation lias been described in the preceding paragraph.-. Cancer of the larynx is favorablv influenced I>v high-frequency currents in conjunction with the r-ray applied in the same way as for tuberculosis. In a general way the effect of the ./--ray is alterative: that ot the high-frequency current eliminat ive. The x-ray causes molecular death of a neoplasm and high-frequency currents cause the rapid removal of the waste products. Chronic Laryngitis. Here the indication is for the vacuum electrode or the effluve over the outer surface of tin t rode of ball shape should be used which w even with the electrode in good contact witl should !;-; I'bout 100 milliamperes. High-frequency Current* in Dixcaxt:* of tin Stomach and Intextincs Aton a of thi Stomac/i vith or irf thoi.it dilatation is promptly and favor- ably influenced by high-frequency current.-. Such a case was that of a retired naval officer who was invalided home from t he Philippines during the Spanish-American AVar with the nervous breakdown which affected so many of our officers there. In his case the trouble was chiefly gastric, and all t he-e seven years or so he had suffered from mom- mi; vomiting and abdominal pain. These symptoms had become worse of late, and when he came for electric treatment lie was unable 1 to keep anything on his stomach, and the question arose as to whether any malignant trouble was developing. After a test-meal an examination was made by the late Dr. Kemp, the gastro-intestinal specialist. lie found that the stomach extended to 2 inches above the umbilicus and that , therefore, there was no dilatation. Atony was evidenced by marked splashing. Free hydrochloric acid, L'O; combined hydrochloric acid, o">; total acidity, 00. Some lactic-acid fermentation. The patient was placed upon the usual medicinal treatment for such a condition: resorcin, hydrochloric acid, mix vomica, and cinchona; and peptonoids in place of his customary whisky. The electric treatment consisted in the application of a vacuum electrode over the stomach and adja- cent regions for ten minutes with a current of loO amperes and without spark-effect; this being followed by the same application along both sides of the spine from the upper to the lower limits of the scapula. In this region some spark-effec. was cautiously applied. It had to be slight' because of the tendency of the skin to become covered with inu- red >pots. The high-frequency currents were begun about seven or eight days before it was convenient for him to begin taking the medicine. Improvement began immediately and lie did not have a single attack of vomiting after tin? electric treatment was begun. During the course of the treatment, which lasted two months, he did not have a single one of the frequent attacks of vomiting and pain which used to incapaci- MKIHCAL ELECTRICITY AND RONTGKN RAYS late him for a day at frequent intervals. Quite early in the treatment he was rejoiced to find that he could brush his teeth before breakfast without being nauseated. He was apparently entirely cured at the end of the course of treatment. Constipation may often be cured by treatment with high-frequency currents, as in the ca.-e of a young lady who had been operated on for hemorrhoids. The constipation which originally brought on the trouble, was nut relieved by the operation and did not yield to ordinary medic- inal treatment. The electric treatment was given by means of a glass vacuum electrode whose conducting cord was connected directly with one pole of an .r-ray coil. A primary current of about 3 amperes was used with a Caldwell-Simon interrupter. The electrode was passed all over the abdomen and some contraction was visible as first one and then another muscular mass was influenced hy the current, (liven in thi- way it is desirable to avoid a spark-effect, and if a strong current is used derided muscular contractions may be produced. The result of a fe\v weeks' treatment was a cure which has continued for the two year- which have elapsed since that time. Similar results have been re- ported hy l-'leig and Friinkel. 1 High-frequency currents are so easily applied and with the proper equipment so readily measured and con- trolled that they may occasionally be tried in a case in which the com- bined galvanic and faradic current might possibly he better. Noth- ing hut benefit is to be expected from the' high-frequency currents, however, and if they are not effective a change 1 may be made to the other form. A certain number of cases depend upon a spastic condition of the sphincter ani. and for these a rectal vacuum electrode from either the d'Ar.Minval transformer or the lower polo of the Ondin resonator Is held in the rectum while a current of 150 milliamperes is allowed to How through it lor three, four, or five minutes. It is necessary to stop occasionally to allow the electrode to cool off. Suitable electrodes are 1 ' wit h all insulatei 1 stem. . High-frequency currents are ahno-t a specific in this ihe first report to be made upon the subject was bv the ']', ami .-nice that time he has treated many cases, of y Jx- cited as examples. One patient was a large, strong ""oi had >uffered ironi coin is for four years in spite of eatmenl by her brother who has for many years been a ' ' '' 1-oard of Health physician. The trouble was always worse .' ". < '.'. and during the summer of J'.KKi it had assumed a dvsen- She had twentv-five bloodv movements a dav for a '!:, medicine, whatever it may have been before-, was and catechu, and an electric treatment was given 1 ni. She paed a comfortable night and the following riicr;i))cuti(|Uc I'liy-inur; Arch, of tin- Hont^rii K.-iy, June, ti.-. N'cu York Medical .Journal. .July 1 1 , I'.tli:-;. HIGH-FREQUENCY CURRENTS 611 day had only one movement. Ten treatments were given during the next throe weeks and resulted in an entire cure, from which there has been no relapse during the four years that have ensued. The treatment employed in this case was a combination of the x-ray and vibratory currents. A tube of moderately high penetration was used, rays about No. Benoist, with the anticathode at a distance of about 12 inches from the bare surface of the abdomen. An S-inch Ruhmkorf'f coil was used with a Calchvoll-Simon interrupter, a primary current of about 3 amperes, and an exposure of four or five minutes. This was followed by the application of a glass vacuum electrode all over the surface of the abdomen, but especially over two or three painful spots. The conducting cord was attached directly to one pole of the a>ray coil. As little spark-effect was produced as possible. The other case is typic of a more numerous class. The patient is of a highly neurotic type and has had many tilings to worry and excite her. Before coming under treatment she had for a number of years been almost daily passing a largo gelatinous mass, which looked as if it could be straightened out into a thick cord or ribbon or tube many yards in length. It looked like some new and strange kind of worm. As the patient had a marked family history of tuberculosis a pathologic exami- nation was made, the report being that the discharge contained essen- tially mucus and granular epithelial detritus. There was always severe abdominal pain preceding these movements. Reliance was placed upon the .r-ray and a vibratory current given in the same way as for the other case. A cure was promptly brought about and for the last two or three years there has been no tendency to a permanent return of the trouble. When she gets terribly excited, however, there are attacks of the same nature lasting for one or two days. If she is in the city and receives a treatment the pain is immediately relieved and the attack brought to an end. The subsequent occasional single treatments have been by vibratory currents alone through the vacuum electrode, The benefit produced in these cases is due as elsewhere to what can only be termed the intense vitalizing action of this current, not to any direct bactericidal effect. L'ttlnrrhal Appendicitis. A certain number of chronic cases in which this seems to be the condition are permanently cured by the same technic that is so effective in colitis. This has been used by the author not with a view to the avoidance of a surgical operation where that was indicated, but as the best method of treatment where an operation is not required or when it has been performed and there are still adhesions mid infiltrations to b< eliminated. JKxcellent results have been obtained when the vacuum electrode from the Oudm resona- tor is applied over all the affected portion ot the abdomen for about twelve minutes' with a current of loo to '-'no niilliamperes. A good contact is desirable and the electrode should be in constant motion. High-frequency Currents in Diseases of the Rectum. Doumer. in 1 V7,' was t he first to publi-h any larire number of rectal cases 1 reated by high-frequeiiey currents, and his success was quickly corroborated by the reports of Sudnik.- Stembo. :i Tschdanow." 1 and more recently 1 \nn. .rKlcM'trnhiolnuMf. - [hiil., ivt'.i. :; Dontra. Mc. Miotkin's Hospital Zciluni:. N~o. "(). 15)00. 012 MKDICAL KLl-XTKK ITY AND K(")NTCKN HAYS by Bilinkin 1 aiul Marque-.- Hundreds of cases have been reported altogether and fairlv accurate* conclusions may be drawn from them. I*' is* it re of tin /////> is in about one-half the cases cured by from three* to nine applications and there is prompt disappearance of the accom- panying spasm of the sphincter. Other cases require many more treatments and some do not get well till the sphincter is stretched. //, 'tiorrhn'nl*. Simple vascular masses of recent development show about .")ii per cent, of complete cures and decided benefit in almost all the others. The number of applications is from four to eleven. Inter- nal and external vascular masses with occasional acute exacerbations, bin without hype-rtrophic changes, are almost alwavs greatly benefited and one-third of the cases are completely cured. In all the above cases the accompanying constipation is usually cured at the same time as the local lesion. I 'lii'nii if Ht'Hini'i'himix ii'it/i I Ini'kt iniii/ urn', Irntdhiltti/ nj tlic Folilx <>J > . '/ directed to t he cause of the t rouble would be \ the' greatest value also m cases which we're operated upon and .' be used either before or after the operation. /',, .,,-,,.' , l/cmnri-lioiilx (J'rolitjixi irilli 1 ! ', ,//,-//, ssn/tlu S/>lu'iicti r] . liiliukin treated (i cases, eight to nineteen applications, -1 were cured, '_' much improved; m everv case the general tunic effect was verv great. i in 'I i-ii i ni 1,-nl ni/is to II ii//i-/'/'n/u< nrij Currint* in lit nioriiiotda. I'ln had re-tilts in exi-eptional cases are an increase in swelling, con- r-ldi-i ' . ;il)il -nine lieliiorrhage ; in others all acute exacerbation "I the' condr lein. \\heii this takes jilace this line of t re-at ine-nt had bel tep be a 1 .a 1 idolied . ;; I In rtmifu tn triitniH /x a nn lln>tl nl //'in// ni/ hiccate them. The liemorrhnid i- cut off \\ith the scissors close to the clamp. HKill-FKKQrKNCY CL'UKENTS Pruritus Ant trith 3foi*t Eczcnui. Bilinkin treated lo cases, ioui to seven applications, \vith a cure in ('very case. The present author, however, has encountered certain cases of pruritus ani which would not yield to this or any other form of treatment, operative or non- operative. local or general, except the .r-ray, which seems to be a specific. There is nothing magic about the high-frequency current.-, though they are very effective in most cases of rectal disease. Pnralysu, of the Sphincter An!.- The most difficult cases to cure are those resulting from overstretching in the operation for hemorrhoids or fissure. One such patient who was treated by the author had been operated on for ulcers of the rectum by one of the foremost rectal surgeons. The cast 1 had been one of spasmodic stricture of the urethra or spasm of the sphincter vesiea-. and the patient, a man under forty, had frequently been entirely unable to urinate. After waiting a few hours he could do so. A stricture of large caliber was diagnosed and he was operated on. There 1 was temporary relief from the retention of urine, but on the return of the trouble the ulcers in the rectum were discovered and were regarded as having in a reflex way produced the difficulty of micturition. The operation had consisted in stretching the sphincter ani and applying a Paquelin thermocautery to the ulcer- ated surface. This was of temporary benefit as far as urination was con- cerned, but it resulted in a relaxed condition of the anus and paralysis of the sphincter. For two whole years the patient had to wear a sort, of plug made of cotton and on many different occasions soiled his underwear through his inability to restrain a movement for a minute after the desire was felt. He had to regulate his diet so as to avoid soft movements, which were especially liable to cause trouble. Then- was a return of the difficulty of micturition and a development of abso- lute impotence, no erectile power remaining at all. A Xo. o(i (French) sound could be passed into the bladder. There was a certain amount of ulceration in the rectum. Treatment consisted in the occasional passage of a Xo. )>() sound and the application of high-frequency currents in the rectum, over the genitals, and along the spine. About fifteen treatments were iriven. The impotence was cured and his wife became preirnant. The anus lost its relaxed look and he ceased to be troubled by incontinence of feces, although the sphincter did not regain its full power. He became able to urinate whenever he wished to. The rectal ulcers healed. From this condition then 1 has been very little back- sliding during the year that has elapsed since the course of treatment was finished. I-'tx/uln has been reported by Doumer as cured by high-frequency currents, in several different patients, and the method is certainly wort h a t rial when an operation is undesirable for any reason. The cases in which it is most likely to be successful are those in which there is no apparent reason why the sinus will not heal, sive undermining and multiple tracts are not high-frequency currents as a resolvent would be a valuable adjunct to surgery. i'li'rr and stricture of the 'rectum are benefited by high-frequency currents, but perhaps not as much as by the galvanic current, with or without copper elect roivsis. A glass vacuum electrode with an insulated stem of the type illus- trated on pau;e 5S1 is introduced into the rectum and its tip pressed tilt MEDICAL KLKCTKICITY AND KONTCKN RAYS into the narrowed lumen. A current of 1">0 milliamperes from the Oudin or the d'Arsonval is applied for ten minutes every other day. The current should he turned off tit intervals to allow the tube to cool. A successful case has been reported by Crane. 1 in which the trouble appeared to be cancerous. He concludes that it was not malignant because it yielded completely to the treatment. The nntlinil of a i>jili<-iitii)/i in till these rectal diseases may be by a metallic rectal electrode connected with a d ' Arson val transformer and a verv hetivv current : o(H) to 4.">() milliamperes may be applied without tiny sen -at ion except of m i Id warmth ; or a id ass vacuum electrode connected with the upper pole of an < )udin resonator may be used. It is desirable that this should have an insulated stem and that it should be exhausted to quite a hiirh degree of vacuum. This means a higher degree of vacuum than is present when the tube gives a rich lavender colored liirht. the li-ht being, on the contrary, a ste< 1 blue or gray. And when the current is turned in the right direction, so that with the d'Arsonval transformer the u'lass electrode connected with what ma}" be termed the cttthodal or negative pole of the coil a decided admixture of the yellowish green ( indicating the impact of cathode rays and giving origin to .r-rays) is visible;. As a rule, vacuum electrodes are used only with Tesla and < hidin currents and metal elect rodes with d 'Arsonval currents. According to Bilinkin. the latter is more agreeable to the patient and more effective. The shape of the electrodes, whether conic or practically cylindric, is not important. They should be of such a size and shape that they can be introduced readily and that they will make a good contact with the entire mucous membrane of the part of the rectum in uhi'-h they are placed. \Yhen vacuum electrodes tire used the current ought to be 1'J") to !">() milliamperes and the time of application from five to fifteen minutes. The electrode is not moved about, but it i- necessary to stop several times to prevent it from getting uncom- fortably hot. With a metallic electrode the current may be stronger '_'IID to l.")i) milliamperes) and the time of application is about the same. The author's special handle (Fig.3(i3, page .~i.~> ( .h for the vacuum eli ctrodes. i- completelv insulated, the metal socket into which the glass electrode screws bein-j; protected by tin extension of the hard-rubber handle 1 inch beyond the metal. The patient cannot receive a current iroin contact with anv part of the appliance except the glass electrode. - more neci-.--.arv in the case of the different cavities of the body than when applvmg the electrode.- to ,-ome convex surface, but when - :.<'".'. disagreeable the .-park.- troin anv exposed metallic itindle would be, it is easy to see why the fully protected I' Trei 1 in pract icallv all cases. lit may be ( 1 j in a dor-a! posit ion with the t highs veil ical oiled bv crutches attached to the table at 1'J to 11 it- level; or <'_') he may lie upon his side in the Sims gyne- lon; or i-'i) he mav he upon his back with legs and thighs ro.-sed. and knees far apart. The (n-t position is n '1 unless there i- some reason lor not u.-ing it. Jt I'ecium. buttocks, ihighs. and genital and hypogastric the regular operating or examining tables may be iper crutches for this po.-ition. The ordinary iched ''' i Lrynecologic table are unsatisfactory for elec- h.rt V. vn< Mc,!ic;tl .Journal M:ijr:i/inc, Man-li. l!o:,. HIGH-FREQUENCY CURRENTS 01") trothcrapy about the rectum. The position they jnve is an extremely uncomfortable one, which no patient should be compelled to endure for a quarter of an hour, and the anus is not brought into view, but is down close to the table. One reason why the first position miirht not be selected in any individual case is that the operator inijiht not have a table with the proper crutches. Another reason niiNT(i K.N HAYS minutes later. The aKeolus or bony socket in which the tooth sets is partly or completely absorbed. The affected teeth become loosened and eventually drop out unless the process is arrested. The teeth themselves are more apt to be sound than to be decayed, and many of them are of ivory hardiness. So much has been written about the probable causation of this disease that its determination need not be attempted here. The general condition which may be termed the uric-acid diathesis has been said to be the cause of the trouble. Hy other- it i- attributed to a local infection, most probably by a variety of yeast fungus. The present author has treated a large number of these cases and has studied the reports of cases treated elsewhere, and it does not seem probable that it is due to any single specified cause. The etiology seems to present more or less analogy to that of chronic ulcers of the legs. ( lo into any clinic and look at these poor leg cases and you will see fat and thin, anemic and plethoric, people with varicose veins, but a greater number without them, men and women. There is only one striking fact about them, and that is that the percentage of chronic ulcers of the leg among clinic cases is many times greater than in private practice. Of course 1 , the leg is exposed to injury and its circulation is peculiarly liable to interference, but the constitutional condition which causes an ulcer to develop and remain open for half a lifetime must be brought about in many different ways. Similarly. in a case of Higgs' disease, there may be found some definite constitu- tional condition, like uric acid, diabetes, or anemia, which should be remedied. More often, however, the cause is indefinite and the best that can be done constitutionally is to recommend fresh air, exercise, suitable diet, and possibly tonics. Locally, the services of the dentist .-hould precede those of the elect rot herapeut ist . All the stony deposits -hould be scraped away and an application such as peroxid of hydrogen, glacial acetic acid properly diluted, t irchloracet ic acid properly diluted, nitrate of -ilver of the proper strength, or tincture of iodin. The electric application which the author has found successful in cases of pyorrhea alveolaris is a combination of the .r-ray and high- frequency currents. For these cases an ordinary .T-ray tube, such as a ")0-cin. heavy target Miiller tube, is encased in a locali/ing shield having a 2',-inch opening. The rays should be about No. 1 of the Walter or of the |'etioi-t -cale. the resistance equal to a parallel spark of about 2 inches, the primarv current about '.'> amperes, with a 12-inch coil and \\elinelt interrupter and a current of 1 or 2 miHiamporos passing through the .r-ray tube. The anticathode of the tube is about 10 inches from the face, the lip- are open, exposing the teeth and gums, and the time -ure i- fn.m one to two minute.-. Treatments are given twice and are -o retaliated as to produce no redness ol t he skin and no iiit of the moustache. A special .r-ray tube may be used which entirely of lead 'j.la-.- except at the end of a prolongation to be directly to the u'lims. The tube ha- an insulated handle and in po-itioii by the hand. It i- necessary to have conducting > completely in-ula ted as not to give a spark to pat i cut or opera - toi il accidentally touched. The-e are made of I'mlit weight and are al convenience in other cases be-ide- thi< particular one. The li'_:ht- up with a blue radiance, showing the u-ual line of demarca- ii between tin li'jiit and dark hemi-phere-. when the current is of the niilit polarity. No .r-rav e-cape- from the tube, however, except HIGH-FREQUENCY CURRENTS 017 at the end of the prolongation; and the piece of ordinary glass present at this point shows the ordinary yellowish radiance of an x-ray tube. The time of exposure is about the same with this tube in contact with the gums as with t he regular .r-ray tube at the usual distance because the strength of application is about one-eighth as great as with an ordi- nary .r-ray tube. In use this tube will stand only a very moderate current for two reasons: first, that from its small size it heats up readily, and second, that its resistance is much less t han t hat of an ordinary x-ray tube, and with the same adjustment of the x-ray coil this tube will transmit. Fiir. 3S4. El 1 or o milliamperes while the ordinary tube will transmit only 1 or 2 with 1 he same degree of vacuum. This latter Fact contributes very largely to t he rapid overheating of the tube. The t ube should not be run much more than half a minute continuously, and then should be allowed to cool. The redness of the anticathode furnishes the guide to this. Immediately after the .r-ray treatment the high-frequency currents are applied by means of vacuum electrodes placed in direct contact with the gums. These are made with an insulated stem with double glass walls, so that the lips receive none of the current, and this also enables the patient to hold the electrode. For this purpose a very light conducting cord is attached to the electrode by a light clamp. The electrodes are made in different shapes for application to lingual or buccal aspect of the gums (Fig. oS-1). The proper strength of cur- rent is about 7") milliamperes. The electrode is held against one part of the gums for thirty seconds and then changed to some other part. It is not kept in motion as is necessary with the stronger appli- bib MEDICAL ELECTRICITY AND KoNTCiEN KAYS cations that are made upon the surface of the body. The application is entirely painless. The moment the current is turned on a strong taste of o/.one or of nitrogen pentoxid is noticed. This combined method of treatment is given three times a week. The results are very prompt relief of pain and improvement in the ulceration. so that in three weeks the dentist almost always reports that the teeth are better than for six months previously. The teeth gradually tighten up and the tenderness disappears. At about this time the trouble -eeins to have been narrowed down to one or two teeth and these are not at all bad. Just at this stage the patient is only too apt to consider himself practically well and to discontinue treat- ment. This i- a irrave error and is sometimes followed by a return of the trouble. The cases in which the results are most brilliant are those with ragged looking ulceration of the gums. Tho.-e which appear to be susceptible of only a moderate amouet of benefit are those with rather a clean giimival border, but with a pale cartilaginous appearance, looking as if the gums would not bleed if cut with a knife. These cases are often dependent on anemia and the indicat ion is for fresh air, exercise, and tonics rather than for local applications. It appeal's probable that many of the cases of this disease can be permanently cured and the teeth saved by this treatment combined with proper care by the dentist. Action of (In :c-li/ in Pi/orr/na Alrtoluri*. The author has many time- >een positive results in the cure of cases which had resisted the u-ual treatment by the dentist, so that his confidence is not shaken by the theoretic objections which he has heard urged against it. Thus, it ha- been said that the .r-ray is filtered, and so altered in character by pa--ing through the soft and bony tissue.- as no longer to produce the effect which it might if the lesion were in the superficial tissues. The answer to thi.- argument is that a profound effect takes place in the treatment of leukemia by .r-radiation of the marrow of the long bones through the skin and flesh and bone. If the blood-forming cells in the bone-marrow can be so affected as to produce a radical change in the con-iit ut ion of t he en t ire blood in The body, it is easy to comprehend that nidi a radiation can produce an effect niton the cells lining the alveoli, and experience has abundantly j (roved that this effect is a beneficial one. High-frequency Currents in Diseases of the Eye.- Trm-hot/m. or granular lids, has been treated successfullv bv a combination of the ./-ray and hiu'h-trequency currents. 1 A vacuum electrode was applied to both the inner and outer surfaces of the lid.- three times a week. A current of about ~>() effi : -mi able. A cure was et'lect ed m b-'in- from three weeks to three months. met hoi L- i if ! real im-m for t hi- affect ion. . 1 '". iifttic in rn i- a disc ' :. , oi hiLih -frequency currents. d to the temple by a 1 :: 111:11 !< wit h t he skin The elect rode W< Mild be kept m mot \( ' empie a milder applicat ion of o'. ei tl e Hosed eyelids. iii'n/1/.- 1 .- ni tin iH-nlnr nnixc.h'* ha- been considered under the I' I )i-e;i-<-- of the Nervous System. '<;.'\ 'T. .I'.'innl MI \.lv;inri-il Therapeutic-. New York. May, l'."H. HIGH-FKKQrKXC'Y CURKKNTS 619 High-frequency Currents in Diseases of the Nose. (Jzcna. Suc- cessful cases have been reported 1 in which the crusts and the offen- sive odor disappeared and the mucous membrane assumed a healthier aspect. In about an equal number of cases (10) treated by other observers- the results have been less promising. Even in these cases there was a feeling of relief for twelve or twenty-four hours after each treatment, with less crusts, greater freedom of the nostrils, more liquid discharge", and less dryness of the throat. There was a return of the symptoms, but in the long run there was decided improvement. This consisted in a lessened production of crusts, the nasal mucus became more fluid, there was less offensive odor. Objectively, the mucous membrane appeared but little changed ; the atrophy of the turbinates was about the same. The treatment is not unpleasant and, as may be seen above, even the less favorable results show appreciable improve- ment. Returning, however, to the successful cases, a complete cure was not obtained, but such great improvement as to get rid of the offen- sive symptoms. The method of application is by means of a metal rod with an insu- lated handle. The part which .is introduced into the nose is covered with sealing wax or hard rubber. When the current from the Oudin resonator is turned on an effiuve of fine sparks escapes from the rod through the hard rubber. These fine sparks are applied to ever}' bit of the affected mucous membrane. After a few minutes' application the electrode is removed and if the patient blows his nose all the crusts will usually come away. The application lasts about fifteen minutes and should be made every other day; 50 to To milliamperes is the proper strength of current. Xo cocain or other local anesthetic is needed. Unij-fcrcr. The author suggests the use of a glass vacuum electrode, insulated by a double wall except at its extremity, which may be applied to all parts of the nasal mucosa, but especially to the inferior and middle turbinated bones. It is very easy to get a spark-effect from an electrode of this size even if the contact is pretty good: and this seems to be the indication in these cases. This vacuum electrode will give one all the benefit of the high-frequency currents combined with the influence of the ultraviolet radiation from the tube. A similar application mav be made to the outer surface of the nose, at the sides halfway from the root to the tip. The strength of current fin 1 the interior of the nose is from oO to 7") milliamperes. And for the outside a current of 75 to 12o milliamperes, applied by a somewhat larger electrode with an uninsulated stem and terminating in a ball. This shape gives the spark-effect desired in these cases. Sinn*ifin.- Chronic inflammation in the frontal sinus, the ethmoid cells, and the antrum has yielded to high-frequency applications at the author's hands. A small glass vacuum electrode has been connected with the Oudin resonator and is passed over the surface of the affected parts of the face by the patient herself (Fig. oS-">\ The strength of cur- rent i- -uflicient to redden the skin, but not to cause pain. High-frequency Currents in Diseases of the Ear. Tinnitus MEDICAL KI.KCTRien Y AND KONTCKN KAYS Aitrinin. The etfluve from an < hulin resonator is applied by means of an elect rode consisting oi' a bundle of fine wires surrounded by a "'lass cylinder. The ulass can be made to project anv required distance beyond the wires; the object lieinu' to secure ail effllive of fine violet -parklets. This is applied to the skin behind the affected ear for three to six minutes; it is practically painless and is alwavs easily borne. There is some redness of the .-kin and even a slight burn if the application has been too vigorous. The patient's sensations are not a reliable guide, a- even entirely too -Iron^r an applicat ion would not be really painful. \ currenl oi ;iboul KM) rnilliamperes with the end- of the wires well led \vithin the "la.-- cuff would be proper for a starting-point. ! .. !<"). p. .")M. -how- the proper elect rode. I he application -hould be made three time- a week and mav be to ears according to the case. Iinbert 1 ha- treated a larti'e r 'it ea-e- lit tinnitus aiirium due to a \'ariet\ p /iai/ be mentioned: Tclangiectatic rcrlm** oj llt< nos< may be treated by the effluve or spark- from the Oudin reso- nator, or by the application of a condenser electrode and d'Arsonva! currents. The same applications are useful for liipitx I'lilt/arix and ery- ihi t/Kifni/i N. The effluve is valuable in acne, itn/x-tit/o, Inrpc* zoxter, furunciiloxis, and xi/coxi*. Alopecia sometimes yields to the effluve. but more often requires sparks. The application of high-frequency spark- of different strength- i- a wonderful resource in epithelioma and in carcinoma and lupus. Freund and Fabroz/i 1 find that high-frequency sparks applied to the normal skin produce 1 inflammation of the mo-t -uperficial laye-rs, givat dilatation of the veins, extravasations of Mood, and vacuolization of tin. 1 walls of the 1 arteries. There' may be 1 destruction of the entire epithelial layer. Oudin regards these results as partly due to the ultraviolet radiations which accompany the product ion of the-e spark-. U'a/'/.v, xninll epithcliomata, and molt* may be destroyed bv the u-e 1 Annali di cllctricitii mnlira, 1 '.):>. No. 11. (>22 MEDICAL ELECTRICITY AND RONTGEN RAYS of high-frequency currents as a cauterizing agent. For this purpose a metal electrode or small glass vacuum electrode is held upon the spot to he treated and a current of !;">() milliamperes is sent through it by the ( Hulin resonator or the d'Arsonval transformer for ten or twenty seconds. Histologic investigations hy Arienzo and Fahrozzi 1 show that tlie epithe- lial elements of the skin are most powerfully influenced, active hyper- emic changes taking place in the .surrounding area, with exfoliating scabs as an end-product. The repair of the lesions produced by the treatment lakes place by a process of leukocytosis and phagocytosis in '!:' -ubfutam-iiu- ti.--.ucs. rc.-ulting in the complete regeneration of the 'pit he!i;d -trata of the -kin. The resulting ciratrix i- preferable to that produced l.y the operation of chemic can-tic.- or exci-ion and the appli- at ion i- ctinipa ra ' ivl v | >ainle-s. I- in i n i - o s ' i ;;vs -how an ex t feme case t real ed 1 >v t he a ut hot'. Tin 're 1 .I'-ur. A.iv;inri> applied at different point? over the entire surface, not lonu; enouirli at one place to produce necrosis (124 MKIHCAI, KLK(TKlS',t shows a cavernous epit helioma or endot helioma of t lie face which re-i-ted .r-ray treatment and which was completely destroyed by a -iniile ap])lication of -park< from a metallic electrode connected with one pole ( it t he refloat or. Figure :!'.( i i- of a case of flat, scaly, pigmonted keratosis, apparently threatening to liecome epithelioma, which made such slow progress under .' tieiitment that a sinu'le application of hifi'h-frequency sparks wa- with complete removal of the lesion. fie author's hijih-frequency -park elect i-od<- and ,-pecial technic are iftalit unle-- the patient i< under a general ane-t het ic. 'hey render the application painless fsee p. ."*().'> J. ':. '-' are practicallv th' 1 onK" case.-; \\\ \\hlch ;m irnlatr/e ('ffect i.- <\. (".-ually the application of hiirh-fi'equency currents i- so ev< n witli verv sti'on^ current- no irritation of the skin is i'-i-d. I hi- i- !_;cnerallv afcompli.-hed b\' maintaining a uood con- -l.in ,-ind b\" keepini;' the \'aciium I'lcct rode iii constant in. I mpolar applications of L'.~0 milliamperes may be ^i\'en ithoin irritation. If. for any reason, it is necessary or ':>.' to '};< application through \}\<- clothes or bandage.-, the : be pressed quite firmlv, it should be kept in motion, ; be moderate, not over 1 ">0 milliamperes, and the \vhole hiili-fre()uency a])jKtratus ,-hould be such as to ni rather than ten-ion. Tin.- difference manifests une r-a.-e b\- -iMi|ilc warmth \\hen the electrode is in contact hen the appal'alu- I- adju.-ted lor tension there N'CY CUllUKNTri 025 are disagreeable sparks passing down from the outer surface of the vacuum tube even when the latter is in good contact with the skin. Increase in tension is produced principally by lengthening the spark-gap between the Leyden jars. The volume of current is increased by using greater self-induction in the primary coil, arranging the interrupter so as to give rapid interruptions and a strong current, and using a large number of turns in what may be termed the primary part of the Oudin resonator or the d'Arsonval transformer. It is also increased by the use of vacuum electrodes having leading-in wires; and especially by the use of metallic electrodes. The eifluve is increased by a combination of the elements which increase both tension and volume. Acne is benefited by the local application of high-frequency cur- rents, either theeffluve or by a vacuum electrode. The latter is more useful. The electrode should be dome shaped and at least 1 inch in diameter, the flat surface being applied to the skin. The use of talcum powder is desirable to secure a good contact while the electrode is kepi in rapid motion. A current of about. 100 milliamperes should pass through the glass electrode for about ten minutes and sparking should be avoided. The applications should be made three times a week. The beneficial effect is largely due to simple stimulation, but there is also a germicidal effect from the ozone generated in the tissues by elec- trolysis and from the ultraviolet ray produced around the vacuum tube. The electrodes best adapted to almost all high-frequency applications are those which produce the greatest amount of ultraviolet light. Its presence is demonstrated by \Villemite, the 4 same mineral that is used as a test for radium rays. The x-ray and high-frequency currents may be combined in the treatment of these cases. It is easier to get a per- manent cure in these cases by using in addition to the electrotherapy the author's treatment by tar-soap friction, xinc and salicylic ointment, and rhubarb and soda internally. This is given in detail on p. 1172. Treatment by incision and curetting is to be avoided. It often results in the most frightful scarring. Success ma}' be confidently expected in these cases, but it requires months of treatment. Special sources of reilex irritation like phimosis should be remedied. Alopecia. -The application of a vacuum electrode carrying a cur- rent of 100 to 150 milliamperes is an excellent stimulant to the hair- follicles and is a very convenient form of treatment. The prognosis varies in different cases. In ordinary cases of a tendency to baldness high-frequency currents are used alone, but in alopecia areata the.r-ray is required as an adjuvant . Treatment of Alopecia Areta hi/ Hii/h-frcqucnry Sparks. Bordier, Bordet. and others have reported successful cases. Bordier 's technic employs for recent mild cases an Oudin spark electrode with a glass sleeve 1 . This is connected with one pole of a large d'Arsonval trans- former, the other pole of which is grounded. A shower of tiny painless sparks are applied in this way over one p;irt after another, long enough in each place to produce intense redness, but not vesication. It requires only a few seconds in each place. Bordet' cured a case which had resisted all sorts of treatment, including the above technic. He applied the same fine sparks for twenty or thirty seconds at a time in each place. The entire seal]) became very red and the fifteen or twenty separate places to which the sparks had been applied until the skin 1 Arch, d'clcotricitc innlicalc, Sept. 2.1. 1907. in b'2() MEDICAL ELEC'THK'ITY AND KONTGEN KAYS turned white each time became blistered. This latter condition was succeeded in a day or two by thick crusts, sometimes moist, resting on an indurated and very congested base. It took fifteen days for a very superficial slough to separate, leaving a superficial, flexible, pink cicatrix which became brownish about the thirtieth day. This was followed by the appearance of fine hairs. The treatment, which was a painful one, was repeated every eight days until two-thirds of the hairy scalp had been vesicated in this way. The hair was completely restored in about nine month-. A case now under treatment by the author is shown in Fig. 391. A glass vacuum electrode connected with the Oudin resonator is lightly rubbed over the bald areas with as considerable spark effect as can be borne without much discomfort. This treatment causes redness, of the scalp, but no blisters or scabs. The same t reat merit may be applied so as to produce the more severe ef'iecl above described if the vacuum elec- trode i- held ;tt a little distance from the surface and a shower of tiny -pa rk- i- a Mowed to f;i II upon 1 he same -pot for t went y or 1 hirt v seconds. ('hilhluitix are benefited by the analgesic and vasomolor tonic effect of the hiidi-freqiiency current -. A vacuum electrode is used with a current of about 1 (K) milliampcres.' l:<'-.i inn in practically everv form i- benefited by the application of hi ( _ r h-t requencv current-. A local application of the effluve or by vacuum elect null - i- u-uallv be-t . This should not be confined to the region of the le-ion, but should extend to a third of the surface of the HIGH-FREQUENCY CURRENTS 027 body. For instance, for eczema of the legs the application should be made to the whole of both lower extremities. The vacuum electrodes should be applied over smooth dry bandages or underclothes. A current of 50 to 7") milliarnperes with scarcely any sparking effect even through the 1 clothes is applied directly over an acute eczema, while about 150 milliamperes with as little .sparking as possible is applied over the un- affected skin. The applications should last about fifteen minutes, during which the electrode is kept in constant motion; and should be made three times a week. As the case improves, stronger applications are made over the lesion. The benefit is due partly to the local effect, but very largely also to a systemic effect, by which all the processes of metabolism are stimulated and the condition of suboxidation which causes so many of these cases is remedied. There are certain cases in which the skin of the whole of both lower extremities is thickened, indurated, and brownish red. This is accompanied by annoying pruri- tus and seems to be caused by the uric-acid diathesis. High-frequency currents produce a favorable effect applied locally or generally. 1 Furuncle* are favorably influenced by the local application of high- frequency currents; vacuum electrode, 100 milliamperes for ten minutes, with the electrode moving over the entire region. Sometimes they are aborted; sometimes made to heal more rapidly after incision. This is the case also with felons and cellulitis; the current having an indirect bactericidal effect. A local application of high-frequency currents immediately before an operation for cellulitis or abscess acts as a local anesthetic. Herpes zoxtcr, with its half-girdle of eruption and severe pain and its subsequent depression of all the vital forces, is successfully treated in this way. There is perhaps no better analgesic in zoster and inter- costal neuralgia than the application of high-frequency currents of 100 milliamperes by vacuum electrodes. And if the application is made not only along the course of the nerve but also along the spine and over the abdomen, the disappearance of the eruption and the improvement in the general condition are very prompt. Herpes in other regions and of other types rarely requires this treatment and generally there is some underlying cause whose treatment is more important than that of the cutaneous lesion. Impetigo, again, is a, disease favorably influenced by the local appli- cation of high-frequency currents freely over all the affected regions; 100 milliamperes is the proper strength of current with the Oudin resonator and glass vacuum electrodes with leading-in wires. Indurated cicatrices yield to treatment by high-frequency currents; vacuum electrode 100 milliamperes for about five minutes three times a week, keeping the electrode in motion. The .r-ray has the same effect of causing the disappearance of the induration by a process of absorp- tion and the two methods of treatment may be combined. Kach ses- sion would consi>t of a mild application of the .r-ray followed by the use of t he vacuum elect rode. Kcloul has been treated by the .r-ray and high-frequency currents and often successfully. 1 A- medicinal agents in these rases the best effects are obtained from boric arid ointment externally and two .">-<;rain tablets of salophen three or four times a () per cent. The application is a local one. either by the effluve or by means of vacuum electrodes. Iii the latter case a current of about 100 milliamperes should pass through the electrode for about ten minutes, the electrode being kept in motion. There are cases which sometimes do not yield to r-ray or ultraviolet ray treatment, but in lupus vulgaris either of these methods seems preferable to the treatment by high-frequency current -. M nil usi'ii 1,1 rontri(jiosnni is one of the disease- in which a cure has been reported from the local application of high-frequency currents 'irlass vacuum electrodes with a current of 100 milliamperes). I'rnrit us. -For this symptom in almost any locality high-frequency currents are almost a specific. Pruritus ani is considered under the head of Rectal Diseases. p'J.-ewhere the application should be by the effluve. taking care not to give many act ual sparks, or by the vacuum electrode. In the latter case there should be a good contact with the skin, facilitated by the use of powder, the current should produce very decided warmth with hardly any sparking, about b">0 milliamperes Relief i.- usually apparent at once. The production of a slight rash like " pnckl v heat " bv high-frequency i real men t is usually unnecessary and in thi- case would be <|uite undesirable. /'."W/'/N/x yield- to high-frequency treatment just as it does to so other stimulating local application-, and some cases have been reported where the re.-iills appeared to be permanent. The effluve or t he Lrlas.- vacuum elect rode is applied over the < ht't'erent lesions wit h a :|i o| 7") to 1 1 H i milliamperes and -ome slight .-park-effect cau- pli< d. The latter had better be more of the nature of a loose con'act with the skin than ot .-park- trom an electrode held at any ce from the surtace. I In- treatment certainly has i he general system and so will probablv vield a : ,,:'..' , rcentage oi cures than the ordinary medicinal local ivc in simple in- HHlH-FKKQrFAVY CUKKKXTS ()29 selves. The preferable method is to have some thin dry covering over the surface and then to apply the vacuum electrodes with a current of not more than 100 milliamperes. Have very little spark-effect and keep the electrode in motion. Here, as in psoriasis and ec/ema, the application is much more cleanly, agreeable, and convenient than any local medicinal application. And to the local effect is added the beneficial influence upon the sys- tem at large. Skin-grafting. Dr. -I. Sherman \Yight of Brooklyn has used the high-frequency currents in the surgical operation of Thiersch's skin- graft in;. The surface of the ulcer is freshened by cutting away a very thin layer. The usual slow process of checking hemorrhage by pres- sure is dispensed with, the large skin-grafts being at once applied. Sparks from a high-frequency apparatus are then applied To arrest hemorrhage by causing coagulation. The pointed metallic electrode is held about I cm. above the surface of the graft. The grafts are said by Dr. Rushmore. another surgeon who has used the method, to adhere better and be more successful than if the electric application had not been made. Ulcers. Chronic ulcers anywhere and of any nature are quickly and favorably influenced by high-frequency currents. Many recom- mend the efHuve, but as may have been noted alreadv the author's favorite method is by rubbing a vacuum electrode over a light, dry covering. Tsing this method, the current should at first be less than 100 milliamperes with as little spark-effect as possible. After the ulcers are practically healed, a stronger current may be applied, and when there is no raw surface at all, loO milliamperes will be found to have a good effect upon the swelling and induration so often present, but even then care should be taken not to have any appreciable sparking, and at the appearance of a little red punctate eruption the strength of the application should be materially reduced. 1'crforatinij L'lcer of the Foot. Oudin 1 treated such a case successfully with the resonator current applied through a metal probe covered with :-otton wet with a solution of cocain. Xanthoma Multiplex. Cases of this disease have been treated successfully with the .r-ray alone'-' and by a combination of the .r-ray and high-frequency currents. s The patches treated by high-frequency currents disappeared if the application was severe enough to blister the skin, otherwise they were not affected. In all these cases where a local action upon the skin is desired tin- glass vacuum electrodes seem to be the most effective. This is attrib- utable in part to the ultraviolet ray generated by the tube. The presence of this invisible light can be fluorescence excited in a piece of Wil elect rodes. High-frequency Currents in Periostitis, Cellulitis, Phlebitis, and Varicose Veins, etc. \\ rioxtitix. Bilinkin* gives a description of 1 1 cast's treated by high-frequency currents; s of them were tuber- iti ( Mlicid ilc la Snrirtr francaiso. il'i-lcctrothcnipie. .Ian., I'.'H. vol. \i\. Kvan- 1 Hullo I'.HU. abstract cil in Arc! ()30 MEDICAL ELECTRICITY AND HOXTGEK HAYS cular, and all were cither cured or very much improved. Tho appli- cations were by condensing electrodes, a type in which a metal rod passes down almost the full length of the hollow glass electrode, being separated from the glass wall cither by a partial vacuum or by oil. The discharge from such an electrode is unusually rich in the spark element. The applications were of five minutes' duration three times a week. A case of extensive tubercular periostitis of the tibia was apparently entirely cured by twenty applications. A tubercular affection of the metacarpophalangeal joint of the thumb with entire loss of motion and atrophy of the thenar eminence and involvement of the skin, with the formation of five sinuses, was likewise treated. Twenty seances resulted in diminution in the size of the swollen osseous extremity and the motion in all directions had begun to improve. Dr. Bilinkin observes that 1 IL'. '>'.!'_'. Condensing eU'rtrodi- lor surface application. "in rases where the process had advanced to suppuration and sinus formation the response to treatment was quicker than when 1 the skin was intact." This agrees with the author's view that the beneficial effect of high-frequency currents in suppurative diseases is due to their fa von MIT the process of elimination. An ( hi din resonator or a d 'Arsonval transformer should be used with either vacuum electrodes or condensing electrodes, applving a cm-rent of lo() to !?()() milliamperes for five or Ten minutes three times a week. If the skin is broken the author pre- fer- 10 make the application over dry dressings. The .r-ray is often of service in combination with high-frequency currents in these cases. (',!', ul it!.< and abscess may be very quickly disinfected after incision and caused to heal promptly. The best method of application is over a moi.-t dressing, using a vacuum electrode from the < hidin or the d 'Arsonval, and applving a current of 1 .">(") milliamperes for five minutes. \Yhere there are sloughing tendons or ot her tissues which have to come away bv .-low process, healing cannot take place at once, but even here the application is distinctly worth while because of its analgesic and ant isepl ic effect S. I'lili liifift inn! VnrirnKc Veins. This treatment is effective in reducing the swelling and induration remaining after an attack of phlebitis or periphlebit is. Thi- is accomplished by its eliminative effect; and then if the treatment is continued the circulation becomes normal and the patient is -uved from the consequences oi such t roubl< ulcer and vein.-. In a case referred to the author by l)r. Charles McHur- circuniference of the affected leg was 1 , ; inches greater than he sound I'-tr. There were characteristic brownish-red spots f a silver dnllar or twice that -i/.e. Over i he.-e the epidermis thin ;ind at times there was a serous discharge. There was sitv as vet. The treatment by high-frequency currents (ultra- vi ilet li-ht the patient called it at fi the :.:-! aear;mcr nf the trouble. HIGH-FREQUENCY CURRENTS 631 the present writing the case has remained cured for two years after cessation of treatment. The swelling disappeared and the spots on the skin are normal. The treatment consisted in the application of a glass vacuum electrode, connected with the Oudin resonator, to the whole surface of the limb. Powder was used upon the skin and the electrode was kept in motion. The current was at first 1 oO milliamperes, and even less over the chronic inflammatory spots. Later it was grad- ually increased until 200 milliamperes were 1 applied to all parts of the limb. While under the author's care the patient was taking 10 grains of salophen three times a day and applying an ointment of salicylic acid and C'heeseborough zinc-oxid ointment to the chronic patches, and an elastic stocking was worn. The treatment was given three times a week for two whole winters. Cases with varicose veins require a very much longer time to cure and the author's belief that they can be completely cured is founded upon the marked benefit experienced in a short time by some severe cases. The technic suggested is the glass vacuum electrode with a current of 150 to 200 milliamperes from the Oudin resonator for ten minutes three times a week. Of course, an elastic stocking should be worn until a cure is effected. Ernest Zueblin 1 treats acute and chronic arthritis by the electrodes connected with an x-ray coil and giving a form of wave current. DIATHERMY, OR THERMOPENETRATION These names have been applied to the application of high-frequency currents of many hundred milliamperes or even over an ampere, genera- ting a great deal of heat in their passage through the tissues of the human body. Their frequency must be about a million oscillations per second in order to avoid sensory and motor effects, but their voltage is rela- tively low; and for many purposes their currents .are applied by metal electrodes, either ban 1 or covered with wet cloth, in direct contact with the surface of the body. Thermopenetration or Diathermy. Nagelschmidt has been chiefly instrumental in developing this line of high-frequency treatment. Essen- tially, it consists in the application of high-frequency currents of com- paratively low voltage 1 and great milliamperage, and very often em- ploys two metal electrodes, with or without a covering of wet cloth and connected with the ends of a d'Arsonval coil. The original d'Arsonval high-frequency apparatus, with two elec- trodes applied to the surface, generated a demonstrable amount of heat in the body. At each Leyden jar discharge across the spark-gap a short series of exceedingly rapid oscillations was set up. which very quickly died out. just as the vibration of a guitar string may be arrested by the pressure of the hand. The currents flowed for only a small fraction of the time between successive discharges, and it was impossible to transmit a suffi- cient quantity of electricity through the. bodily resistance 1 without using an excessive voltage. Three 1 different methods are available for producing the stronger currents required for diathermy. One employs an ordinary induc- 1 New York MM. Jour.. January i_V,. 1 kilowatt transformer with the same series spark-gap condensers and d'Arsonval solenoid. These two methods produce damped oscillations, differing from the ordinary high-frequency currents in having lower voltage and greater milliamperage. The third method, which was the first to be employed, uses the undamped oxci[lii(i(i* produced by the singing arc (page h'40\ but, instead of being applied directly to the patient as with the DeForest needle, the current for thennopenet ration is taken from the two ends of a secondary coil which surrounds the self-inductance of the singing arc circuit. The direct electric-light current supplies a current of about (> amperes to an arc lamp which has an inductance in shunt to it. The current becomes an oscillatory one, and the arc emits a musical note' from the rapid alternation between greater and lesser expansion of the hot gases between the electrodes. The currents supplied to a patient, also in shunt, con- -i-t of undamped oscillations of a sufficient frequency, about 1,000,000 per second, and lasting a large part of the time between one stronger flow of current at the electrodes and the next. Theoretically, this seemed to .-olve the problem, but it was very soon found that a lack of uniformity in the operation of the arc lamp of'fr-et all the advantages of the un- damped oscillations, except the quantity of electricity. Surrounding the arc with an alcohol flame improved matters somewhat, and, for certain -uruical applications, this is a satisfactorv method of thermo- The electrodes for diathermy may be of bare metal when applied to MIMIC m-en-itive ,-urface, with a good area ot contact, as when the electrode- ;ire held in the hands and sometimes when they are applied to opposite -ide- of a limb. Very often, however, it i- bet ter to cover the electrode- thickly with cloth wet through and through with a weak solu- tion of .-odium bicarbonate. Diathermal currents are also applied in auloeonden.-at ion, u>itm the same large iiiMilated metal .-heets employed \\ it h the d'Aix nival current.-. It i- e>-ential. except in autocondensation, that there >hall be a good contact when 'he current i- turned on or ott and during the entire dura- tion of it- flow. ! )i-reu-;ird of thi> precaution re-ult- in very hot. pain- ful -)>;irk-. The effects of diathermy, which are mo-t important . are due to t he production ot heat in the ii--ue- caused \>\ the -a me ohmic or frictional HIGH-FREQUENCY CURRENTS resistance to the passage of a current of great milliamporage, us in the ease of a flatiron heated by an electric current. If electrodes about 2 inches in diameter are applied at opposite sides of a piece of raw meat, the latter may bo cooked all the way through along a direct path between the two electrodes. Placed a little di.-tanco apart upon the same side of a piece of meat, the latter is cooked to only a certain depth between the electrodes. Applied to opposite sides of a patient's joint there should at first be no sensation: if there is, it means that the contact is imperfect, the metal not completely covered by the wet cloth, or that there is an abrasion of the skin which should bo covered by adhesive plaster, or that the current is too strong, or. more often, that the cloth is not wet all the way through. After the proper current has been turned on for a very few minutes a sense of warmth, and later of intolerable heat, develops inside the joint. The stage of marked discomfort is an indication for stopping and applying the current to some other part of the joint. The best guide to the right amount of current for local use is the sensation of the patient, and one would hesitate to apply it to an unconscious person or one with sensory paralysis. It ought to feel uncomfortably hot. but not really painful. The electrodes nuixt be in cloxe contact with tin */,/// tchiie the current is being turned on or off, otherwise very hot. painful sparks are produced. A thermometer may show that the temperature of the skin at the place of application is higher than the normal temperature of the blood, and animals have been killed by the application of 2300 milliamperes for an hour. There 1 was high temperature without microscopic lesions. The therapeutic importance of thermopenetration lies in the fact that heat is developed in the depth of the tissues, and not merely upon the surface, as with ordinary hot applications. The beneficial result is from an increased blood and lymph circulation and increased activity of tissue metabolism. ( louty deposits often disappear, sciatica and other cases of neuritis are often cured: asthma is often relieved as by no other electric means. Traumatic and inflammatory swellings and deposits are benefited. ( Jonorrheal rheumatism is benefited by a bactericide action of the high temperature produced inside the joint. Nagelschmidt's autocondensation couch for diathermic currents is of wood with a metal plate under and a hard-rubber plate over it: and entirely covering the patient is a flexible 1 sheet of metal netting with a flexible rubber covering. Schittonhelm's is like the one used by the author ( page 1 60S). Monopolar applications of diathermic currents are made with the same condenser electrodes (glass vacuum electrodes and glass or hard rubber electrodes filled with graphite), as for ordinary high-frequency currents, and also with the same eflluvers. Bipolar applications of diathermic currents sometimes employ one or more large metal cylinders to be held by the patient, but very com- monly metal plates of a nature to be somewhat moulded to the surface, -till with sufficient rigidity to allow of firm pressure being exerted by a wooden handle or by a bandage. Some plate electrodes include a resistance thermometer, connected with a separate electric apparatus, which indicates the temperature attained at the place of contact with the skin. ( M hers are made with an insulated backing, and the tempera- ture mav be determined bv touching with the finger. Six thicknesses 034 MKDICAL KLKCTHK ITY AND RONTOEN KAYS of \vct gauze form a suitable covering for the electrodes. Water elec- trodes, like the shallow four-cell hath, are sometimes useful. The marginal effect, which is to he avoided, is a concentration of the current when two electrodes are close together and the skin is unduly heated at the closest points. Special Effects of Diathermy. There is no electrolysis in the ordi- nary polari/ation sense, and the tolerance of the tissues to warmth is the only limit to the strength of the current. In transverse penetration the greatest rise of temperature occurs in the skin, less in the hone, muscle, fat, and least in nerve. In longitudinal or parallel conduction the condi- tions are exactly reversed. In the use of the atitocoiiduction cage the current traversing the solenoid is measured by a hot-win 1 milliampere- meter, between one pole of the generator and one terminal of the sole- noid. Xo important rise of temperature occurs in the body. A small solenoid, through which passes a high-frequency current of 10 or 12 amperes, warms an arm held inside it, and a ball of tin-foil becomes hot instantly and will melt in a few seconds. A finger-ring becomes danger- ously hot. In both autoconduction and autocondensation the therapeutic effect of diathermic currents is due to the heating of the body. With bipolar electrodes 300 or 400 ma. or more causes art ('rial hyper- emia of the skin \vith reflex stimulating effects, such as perspiration and a sense of heat. There is a sedative effect upon itching or pain and also a derivative effect, as well as a temporary increase in blood-pressure consequent upon skin irritation. The regular bipolar diathermy produces no motor or sensory effect except thai of warmth. The skin and blood and living bone are chiefly wanned. The local temperature is raised by therapeutic applications of 40 or 4."> ('. Higher temperatures, even 45 to ~)(f ('., which are below the temperature of coagulation, may injure the tissues by prccipi- tat inir globulin.-. A tempera! ure of S() ( '. coagulate- albumen and sepa- rate.- llie skin into two layers, a blister externally and leathery beneath. l>oiie retain- its consistence, and the other tissues form a soft coagulum removable with a sharp spoon. The final effect is complete carboni/a- t ion. The wcoiiddri) pfn/xioloyic r//Vr/N of (lidthcrniy result from increased cellular activity from warmth reaching the intimale structure of differ- ent organs. Dialhermy through the hear!, with the active electrode over the .-lernum. in therapeutic doses in healthy animals, increases the pulse-rate and raises the blood-pressure temporarily without any effect on the respiration. Transversely through the chest there is a similar ettect upon respiration, but HOIK* upon the circulation. A condenser application, as from a glass vacuum electrode, raise- the general blood- pre-.-ure by -l imulat ing the surface vasoconstrictors. Diathermy through the body, as by the four-cell bath, lower- the blood-pressure bv relaxat ion of t he -plan clinic vasomotors, and t he same is true to some extent with autoconduction and autocondensation. '1 he local etled of diathermy by contact application is evidenced by an experiment of Nagelschmidt. An incision in which hemorrhage ha- been .-topped hy pressure begin- to bleed freely if diathermy is ap- plied from elect rode- at eit her side of, but at a distance from, the incision. After an ordmarv treatment the place of application remains hyperemic considerably lonuer than if the electrode had been pressed upon the skin HKiH-FHEQUENCY CURRENTS 035 without any current, and for quite a while afterward the skin is hyper- sensitive and in a dermographic condition. Another of his experiments shows that diathermy of a part of a forearm in a blue condition from Bier's hyperemia will become a bright arterial reel on the application of a diathermic current. The effect of these currents upon nerves is to produce a sense of warmth, and also to stimulate those which are distributed to glandular organs and increase the secretion of the latter. The effect upon the vasomotor and cardiac and respiratory nerves has already been referred to, and so has the lack of effect upon motor nerves by the currents and the very great effect by the spark. The indirect high-frequency spark, applied to a metal electrode already in contact with the skin, is exceed- ingly active in exciting muscular contraction, and is a valuable improve- ment upon galvanic and faradic currents for this purpose. The effect of diathermy through the brain is to produce 1 a sensation of compression, which passes off as soon as the current is stopped. Diathermy increases the secretion of the thyroid gland. Kxcept for the gonococcus, which is killed by a very slight rise of temperature, diathermy cannot be depended upon as a bactericide in liv- ing tissues; in fact, it is sometimes doubtful whether or not these cur- rents may actually increase the vitality of the germs as well as that of the tissue cells in certain diseases. The strength of current to be applied bears a certain relation to the size of the electrode, to the diameter of the limb when the current must traverse its length, and to the nature of the internal organs traversed. Strength of Diathermic Current and 8ize of Electrode* for Bipolar Application (After Xagelschmult) Electrodes. Milliutnperes. Hand to hand ' ! 3f>0 to 500 Foot to foot ")()() to TOO 2 cm. ( [* u - inch) diameter 1~>0 to 200 4 cm. (1 T -, T inch) diameter 300 to 400 *) cm. C5,' 1 , inch) diameter 900 to 1000 10 by 12 cm. (4 by 8 inches) about 2000 If the skin becomes too hot before the treatment is finished the cur- rent may be turned off and the electrodes dipped in cold water. The patient's sensations should not be taken as the sole guide, because some- times a degree of tolerance is established to currents strong enough to blister the skin. The duration of the application usually varies from three or four to ten or fifteen minutes. The application rctjuirex expert attention even, moment of the time, and should not be entrusted to a nurse or an untrained physician. There is the danger of overheating the surface tissues, and faintness or col- lapse from tin 1 passage of too strong a current through the heart or the brain. Diathermy in Circulatory Diseases. -The conditions in which the treatment is chiefly useful are classified by Xagelschmidt as high arterial tension, relaxation of peripheral vessels, cardiac hypertrophy, cardiac dilatation. Anomalies of Khi/thm atnl Frcf/Hcnci/. A large electrode is applied between the shoulder-blades and another over the front of the chest. MKD1CAL KI.K< TKK 1TY AM) HONTCKN KAYS This stimulates the heart muscle and relaxes spasm in the coronary arteries, and is useful in cases of myocardial degeneration, some valvular lesions, and angina pectoris. Aneurysm of the aorta shows subjective improvement, and a case of coronary disease which resists treatment by diathermy is regarded by Xagelschmidt as indicative of beginning aortic aneurysm. Arteriosclerosis of the brain is treated by a bipolar applica- tion or by a small solenoid surrounding the head. Local asphyxia, intermittent claudication, and Raynaud's disease are all treated by a bipolar application. Kflluves and condenser applications are indicated in low arterial tension from relaxation of the peripheral arteries, and I have obtained remarkable results in cases of phlebitis. \\ . Martin 1 in a case of pseudo-angina pectoris used a ^ x 4 inch metal electrode in front, and one measuring 4 x f) inches near the spine at the -ame level, applied thermopenetration, SOO ma., for thirty minutes. \ ibration was applied at the seventh cervical and first dorsal interspace*, alternating with percussion. Also for intestinal stasis a slow surging sinu- soidal current was applied from front and back electrodes. Later neuritis of the shoulder was tested by the static wave current, and ?,-inch gap caused pain, so the same was used for treatment, also indirect sparks. I )e Kraft considers painful muscular cramps in elderly people as due to local arteriosclerosis, and reports great benefit from diathermy, very mild at tir-t. applied by small disk electrodes. Diathermy in Respiratory Diseases.- The bipolar application. through the chest from side to side, is excellent in acute and chronic bronchitis and pleurisy, and applied at the upper and lower extremities of the sternum it is a specific in asthma. It often has a beneficial effect in pulmonary tuberculosis, but sometimes causes an exacerbation and had probably better be combined with the .r-ray in this disease. Diathermy in Other Internal Diseases.- Applied to the kidney in a number of different diseases it increases not only the water but also the solids of the urine, pathologic or normal, and eventually leads to a healthy activity and seems to be indicated in chronic Bright 's disease, where it -eems likely to afford a means of more permanent relief than the opeiation of decapsulation. It is especially indicated in cases of hiirh arterial tension when the primary cause lies in the kidneys. It is of the same doubtful value in bacterial diseases of the kidney as of the luni:. 1 )e Kraft quotes ("arro" regarding gastric ulcer. Three cases twenty or t hirty minute- daily for a course of eight tot went v t reatments. < MJC case of dysenteriform colitis of ten years' -landing showed very ults. I )e Kraft counsels caution because of the danger of but agree- with Fur.-tenberg Scheme! that two S x 10 inch electrodes, one over the back and one over abdomen, produce a higher temperature in interior of the stomach with i>00 ma. than with 2000 ma.; I )e Kraft think- strong currents excite reflex surface action which may protect the interior and relieve engorgement of it instead of causing iivperemia. l)iathermy ha- an excellent effect in colitis, intestinal ad- he-ions. and chronic appendicitis, but will aggravate the latter disease if -uppurat ion i- p re-en t. This may be excluded by a count of t he white I'll la r\ and renal colic a re benefited, except . of course, cases \tn>] .I"-: Kli tpithcnipy Mini R;ii!i<>l oppeisite condition of hyperacidity is ml her a contraindication, because of the possibility of a latent ulcer which would be aggravated by diathermy. Nervous gastralgia, dyspepsia, and disturbances of mot ility are benefited. Xagelschmidl distinguishes the cases of exophthalmic goiter due to hyposecretion, and which should be treated by diathermy, from those due to increased secretion and which should be treated by the .r-ray. A single test administration of iodid aggravated a case calling for dia- thermy. Hypert hvroidism is benefited by tincture of iodin, nyij, in a little milk a half-hour before meals, increased to itpiij or v. Hypo- thyroidisin is aggravated by iodin. Diathermy in Gynecology.^ The- best results are from a large indif- ferent external electrode and an active vaginal electrode. Suppurative processes are a contra-indication, but outside of them the current is of the greatest value in adhesions, uterine displacements, old exudates, and ovarian neuralgia. A strong application tot he entire mucous membrane of the uterus is advised in acute or chronic gonorrhea! endometritis. Sterility from infantilism is an indication for this treatment. Genito-urinary Diseases in the Male. Gonorrhea is curable, but thi 1 application is by no means a simple one. A special electrode, with a temperature indicator, must be used which will reach each portion of the urethral mucous membrane in turn and raise the temperature of the tissues to 4)U or 46 C. Santos has succeeded in producing a complete- cure in a single application, lasting ninety minutes. Chronic gonorrhea! areas and indurations and strictures are all curable by the same current applied in the urethra. Incontinence of urine as a symptom of sexual neurasthenia is treated by diathermy intra-urethrally if possible, and. otherwise, with one electrode in the rectum and the other on the peri- neum. Impotence of a psychic type yields to bipolar diathermy of the penis, scrotum, and perineum, and, if due to hypo-esthesia of the glans, the condenser application of a glass vacuum electrode rubbed over the surface 1 is exceedingly effective. 1 have had a number of cases in which the application of a strong, hot current, but with a good contact, so as to avoid a spark effect from the glass vacuum electrode, has produced the most vigorous erections during the application and the most gratify- ing results after a course 1 of treatments. Other cases have responded to the first applications, and have' shown a diminishing effect from the sub- sequent ones and the impotence has remained: a guarded prognosis should, therefore, be given. Acute prostatis should not be treated by diathermy, but chronic prostatitis and prostalic hypertrophy arc 1 bene- fited by it. Xagelschmidt advises energetic bipolar diathermy in every case of acute epididymitis and funiculitis, in which he says it is extra- ordinarily successful if applied long enough and strong enough, and ha> the greatest tendency to prevent occlusion of the 1 seminal ducts. Too weak or too short applications only aggravate 1 the 1 condition. Diathermy in Joint Diseases. The 1 bipolar contact method is used and a sense 1 of warmth should be 1 felt in the joint itself. 1 have 1 seen gouty deposits disappear from the' finger-joints undeT this tivatment. and it is effective 1 also in many other forms of acute' and chronic arthriti- and in tenosynovitis. Among diseases of the nervous system >ciatica is treated succe<- fully by e-neM'getic diathermy of each separate part of the nerve, but. ot course, the 1 effee-t will be only palliative' if the pain is secondary to (io8 MEDICAL ELECTRICITY AND KONTCEN HAYS disease of some internal organ which remains undiscovered and un- treated. Supra-orbital neuralgia and many others are cured. The result in herpes /.oster is more uncertain. Trigeminal neuralgia some- times yields to heavy diathermic currents applied externally, and in some of the cases in which this has failed Nagelschmidt has made an exceedingly valuable observation. He finds that in these cases the attacks of pain are excited by any contact or change of temperature or movement of the mucous membrane of the mouth, and that this hyper- esthesia can be cured by the application of a vacuum electrode to every part of the mucous membrane. Very weak currents have to be used at first, as the application itself may bring on an attack of pain; then stronger and stronger currents. During a ten or fifteen minute 1 applica- tion the current must lie turned off several times and the glass electrode cooled. Chorea minor in children may be cured by diathermy. S. C. Damoglous 1 treated 2 cases of recent hemiplegia supposed to be due to cerebral embolism by general diathermy. He reports complete re- covery. An important application of diathermy is in the treatment of loco- motor nta.ria. Improvement takes place in a great majority of cases, chiefly in the lightning pains, the hyperalgia, and the incontinence. The patient's general condition is also better. My experience has not led. however, to the belief that a cure 1 for the disease has been discovered. General treatment by the vacuum electrode is important. The effhive is suitable for the lancinating pains and the vacuum electrode for the girdle sensation. The latter application is to be very weak at first, but gradually increased on different occasions. Some cases which are not benefited by weak are by very strong applications. Small, very painful areas are treated by the bipolar contact application, which may at first employ electrodes at opposite sides of the painful area in cases where direct contact would excite pain. Gastric crises yield to the efrluve. Vesical crises are treated with a metal catheter in the bladder full of water and an indifferent electrode held in the patient's hand and a dia- thermic current of 50 to 100 ma. By a course of treatment of this kind the muscular tone of the bladder and of the sphincter may be restored, although sensation and the normal impulse to urinate are still lacking. The patient is directed to urinate every three hours, and is enabled to almost or quite empty the bladder. Another effective application is with a higher voltage and indirect sparks; an indifferent electrode is held in the hand or upon the lower part of the abdomen, another metallic electrode extend- into the bladder, and sparks are applied to its external end. This last treatment is also applied to the rectum for lack of mus- cular lone. Painful art hropat hies are benefited by energetic bipolar dial hermy. Diathermy as Means of Epilation. It has t he advantage of requiring only a second to destroy a hair bulb and requires a very small amount of < 'ne's apparatus may be such that the weakest current is too i\\}\ by action along the entire length of the needle in the if merely at the point, and coagulation and perhaps a little In tlii- case a water resistance may be used to reduce the i if current . of a chronic type recurring in the same spot may be treated nic current applied through a needle. iur. Kli-ftrotlii-rujiy ami Hitdinlo^y, vol. \x\vi, No. .'>. June, 19 IS, p. 175. HIGH-FREQUENCY CURRENTS 039 Warts are treated in the same way, and the test of complete coagula- tion is that the wart has become entirely movable upon the underlying tissues. No anesthetic is required, and as many as thirty have been re- moved at one sitting. Xanthelaxma has often been permanently removed in this way by Xagelschmidt. The weakest diathermic current is used and the needle should enter a little beyond the yellow area. The patient should be in- formed that some edema of the eyelid will occur, but will not do any harm. In all these cases, and also in small papillomata, fibromata, athero- mata, and cysts the patient holds an indifferent electrode in his hand and the needle is inserted before the current is turned on. For small superficial telangiectases the needle is not to puncture the blood-vessel, but just to be pressed against the surface during the second that the current flows. There should be enough space between the several points treated to prevent the confluence of the little sores caused thereby. Surgical diathermy, in its different forms, employs very much stronger currents than the above, and is described elsewhere (page 640). An important method is a bipolar application of low tension, high-frequency currents of sufficient milliamperage to coagulate 1 and devitalize the tissues in the neighborhood of the active electrode or electrodes. The maximum high-frequency current required is 400 volts and 2 or 3 amperes. For most purposes both electrodes are active and are thrust into the tissue to be destroyed, but for some delicate work there is one large indif- ferent electrode and another small active one. The effect is one of co- agulation-necrosis. The heat sterilizes the eschar, which may be left to separate naturally, or may be cut away if the operation must be carried deeper into the tissues. This is better than thrusting the electrodes so deeply into the tissues that the effect cannot be observed. There is no hemorrhage. Many varieties of tumors are treated by diathermy, and it is said to be very much the best means of operating upon hypertrophied tonsils. It is suitable for some inoperable cases of cancer, and some- times as a preparation for an operation by closing the lymphatics and lessening the danger of absorption from the cut surface. Hemorrhoids and large or small benign as well as malignant tumors may be treated in this way. Prostatic obstruction due to small growths of various kinds has been successfully treated 1 by the 1 direct application of high-frequency currents by a wire passed through a cystoscope. The wire is insulated, except for an extremity of ', inch, which is pressed against the tissue to be destroyed or cut through. Technic of Diathermy for Hemorrhoids. This is suitable for large* bleeding internal ones. Move bowels. Allow hemorrhoids to pro- trude. Cocainize. A large' dispersive electrode is under the patient's side. A small active electrode 1 is applied, and the 1 henmrrhoid is held with forceps if there is a tendene'v to recede. Turn on e-unvnt slowly until patient says it is hot: turn off instantly. Current about oOO ma. Apply several time's to eliflVivnt aspects, illumphris, "Electrothera- peutics.") Electrocoagulation, employee! by Doyen and others as a preliminary 1 Henry ('. . Bimbee. New York State Journal of Medicine, vol. xiii, Xo. S, August, 1913, p. 410. 1)40 MKIMCAL KU-XTHU ITY AM) R(">XT(iKN HAYS to excision of uterine and other cancers, may have one small, active, possibly puncturing electrode, and a large indifferent electrode or two small active electrodes. In either case the thermopenetration current is used, and the tissues are fairly cooked before 1 they are cut with the knife. Dissemination through the lymph-channels and blood-vessels is pre- vented. Win. L. Clark 1 successfully treats hypertrophied tonsils by high- frequency desiccation when surgical removal is impracticable and especially when a part only of the tonsil requires destruction. Too hot a current is painful in spite of local anesthesia: it burns the tissues instead of desiccating them and tends to produce cicatrical contraction. There must be no air space between the metal point and the tonsil. There is no smoke or odor of burning flesh, but steam is seen rising from the tissues. The correct depth of action is obtained by gradually push- in ii the point into the tonsil; 200 or 300 ma. is possible in this way. Undamped Oscillations, Duddell's Singing Arc, and the DeForest Needle.- High-frequency currents with damped oscillations are analo- gous to the quickly suppressed oscillations of a tuning-fork in water, while the long-continued series of oscillations of uniform extent, when only the obstruction of the air is encountered, gives a better idea of undamped oscillations. One use 1 of these oscillations is in connection with the DcForcxt needle or cold cantcri/. This is like a small platinum blade, which has a handle insulated by glass or hard rubber. The direct electric-light current passes through an arc lamp in which the electrodes are Fin. 'MX. -DcForcst i broad and close together; the electrodes of the lamp are connected with a -elf-inductance and a condenser. Mewed in a revolving mirror, the arc liu'ht may be seen to fluctuate with the alternate charge and dis- charge of the condenser; these oscillations are superimposed upon the direct current forming the arc, and the alternate greater and less heating of the aii' may produce a musical note [Duddell's singing arc). The 1 oscillatory current free from the direct current may be taken, : a monopol;ir discharge, fn tin eit her end of t he self-inductance. insulated wire carries this current to the DeForest needle, lit has oscillations of the usual high frequency, but of very !<. ii-u.-iHy not more than 100. No long sparks, therefore, can t lie needle to t he pat ient . The needle itself remains cool, while ers much li'reater resistance in the tissues, which are In one met hod it does not touch the? surface, but is mil Ha'linlouy, vol. \\xvi, No. <, September, HICH-FKMQrKXCY (TKHKNTS (i 41 drawn along a straight line near t he surface, the sharp, Iio1 . almost noise- less spark cuts the flesh like a knife and leaves a clean red surface, nol charred or blackened, but without any capillary hemorrhage. The cut surface is sterile. This makes an ideal method for many sorts of surgical cutting, incising abscesses, and especially excision of tumors, where it has the great advantage over the knife that it seals the capillaries and lymphatics against infection from the tumor elements. It is not suited, however, to such work as freeing a nerve or a tendon from adhesions. It would not be a desirable means of operation upon an artery. The other application of the DeForest needle, by which it is plunged into the tissues, produces a regular coagulation-necrosis of greater or less extent , depending upon the dept h to which t he needle penet rates and the length of time for which the current is applied. It is suited to the destruction and sterilization of a tumor of any size or nature. The entire outfit may be portable. 41 PHENOMENA ACCOMPANYING THE TRANSMISSION OF ELECTRICITY THROUGH GASES IT is only static or other very high-tension electricity which can be transmit ted through gases, and the general consideration of the subject may be entered upon at this place. Under ordinary conditions the air or any other gas in contact with a charged body does not become charged and is not a conductor of electricity. If it did so. of course 1 , the body would soon lose its charge by a process of convection; each por- tion of the air as it became charged being repelled and giving place to another portion, whi'-h would in turn take away a certain portion of the charge. Since gases do not ordinarily become charged in this way. it is interesting to note some of the ways in which it can be accomplished and in which they can be rendered conductors of electricity. (lases in contact with the surface of liquids in which splashing or even quiet waves occur become electrified. One of the practicable forms of static machine is dependent upon the charge acquired by a jet of steam. These are some of the ways in which a gas ma}' be ionized, a condit ji m which will be explained later. < Mher means of ionixing gases and rendering them capable 1 of receiv- ing and transmitting electricity are of greater interest in electrotherapy, annum them are especially exposure to the r-niy. the ultraviolet ray, and some of the rays from radio-active substances, also by the passage of a spark from an induction-coil. This is the \\av in which the current i- started through the mercury vapor in some forms of the Cooper I lewit t and similar lamps. IONIZATION OF GASES By some one of t he above processes, or of several others which might be mentioned, some of the molecules oi the gas are dissociated into positively and negatively charged ions. An excess ot positive ions in a f course, cause the "-as to have a char^- of positive electricity. \n exampl' of the way in which this may com'' about is seen when a tras becomes electrified by contact with an incandescent metal or by the pa-'saLrc of an electric arc through it. In consequence of the high tempe] itiin- some of the molecules of the ira.- become dissociated into positive and negative ions. SOUK- of these combine with the incan- de-ci nt met; , with the terminals of the arc. In the resulting com- llie electropositive element and will take negative ' r ' _ r a- and leave the latter with an excess of positive ions. The Atom According to Sir J. J. Thomson. It is composed of electroi - live particle- grouped in approximately co-planar and and in active revolution, the >vstem heimr within a -phere oi > iectricity. The number of electrons in an atom is ited to ti I hues its atomic weight .' /'-/ are '".MM! by electrons which are -nppo-ed to be II \ \\ ll-.,li, I'l.ll. M:,- . \\1, p. 7K I'.M I. TRANSMISSION OF ELECTRICITY THROUGH OASES 043 -joV< about the size of a hydrogen atom. A positive ion is a group of particles surrounding a positive charge; a negative ion is a group of particles around an electron. In a vacuum tube such as an r-ray tube, electrons travel at an average rate of 20,000 miles a second, and under certain other conditions they may travel as fast as oO, ()()() miles a second. Xo matter how complex the chemic formula of a gas may be, each ion is usually a particle of one or other of the single elements which make up the gas. The ionizution of a gas by the ultraviolet ray takes place only when the light is reflected from a fluorescent substance or from the surface of a metal immersed in the gas, and the gas is only able to discharge; a charged body in its neighborhood which is not illuminated by ultra- violet rays when the charge on the body is positive. The r-ray, on the other hand, makes the gas through which it passes a conductor of electricity, independently of any reflection of the rays, and the gas thus made to assume a conducting state is able to discharge negative!}' as well as positively charged bodies when it conies in contact with them. Air ionized by the .r-ray retains this property if blown through a bellows or if heated, but it loses its condition of ionization if it is made to bubble through a liquid or to pass through a plug of mineral wool, or if a current of electricity is passed through it. A gas ionized by the. .r-ray rapidly Iqses that property by contact with either non-conductors (insulators) or conductors. Electropositive metals lose negative charges to the air when exposed to ordinal 1 }" light and do not require the presence of ultraviolet rays. A gas which has been ionized and rendered a conductor of elec- tricity will transmit electricity at a certain maximum rate which is not exceeded, no matter how much the potential or voltage may be in- creased. The most satisfactory hypothesis is that each ion of gas can carry only a certain charge of electricity, and with a definite number of ions liberated in the gas only a certain rate of transmission of the current is possible. An ion which has performed us function of carry- ing an electric charge apparently becomes neutralized or bound again and is no longer capable of carrying electricity. Hence, a layer of ionized gas ceases after a time to transmit the current, and a thin layer ceases sooner than a thick layer. The maximum rate at which a gas will transmit electricity is different in various gases and is called their saturation current. That of mercury vapor is about twenty times the saturation current of air. It is interesting to note t hat the absorption of the .r-ray by different gases is in proportion to their saturation currents. There are two different ways in which the extent to which air has been ionized is used in practical therapeutic measurements. One method is by observing the time which an electroscope requires to become discharged after having received a standard charge and being to ionized air. This method has been used in the measure- t he amount of r-ray applied in therapeutics, the electro-cope being placed at a certain distance from the r-ray tube and exposed to the direct rays from it at the same time that the patient is being treated. The rapidity with which the electroscope becomes discharged certainly docs indicate t he degree of ion iz at ion of t he surrounding air, but whether this is due exclusively to the influence of the r-ray or even bear.- such a practical relation to it as to form a reliable mean- of r-ray dosage is a serious question. Another method of measuring the electric (>44 MEDICAL KI.F.CTRICITY AND RtiNTGEN RAYS conductivity of ionized air is by having a thin layer of air between metal plates which are kept at a constant difference of potential by a galvanic battery, and ionizing the air by exposure to radium or other rays. The ionization ot the air allows a current to pass across the air space and complete the circuit. The strength of this current a> shown by a gal- vanometer indicates the decree of ionization of the air. This method is in constant use for measuring the radio-activity of uranium, polonium, thorium, and radium. The c. I'his same process ot electrolysis take- place m solids and gases, t hoi '.nl i the molecular change or the change demonstrable bv chemic analysis i.- of t'ar less importance than is the transmission of electricity l.~ secondary effects, radiant and oth< rwise. produced by the trans- missi : of t he ci irrent . If a platinum wire is heated red hot in hydrogen gas. the platinum I- r-oi ' - po-itive]v. and the hvdrogen negativelv. chai'ged. The same i- trui of iron or palladium wires. Air and all oilier gases differ from hydrogen in being positively charged, except mercun vapor, which is tall. I ' ;i i ' ' !' a rc i- passed t h rough o\ v ^en v_a> t he oxygen becomes po^jt . .d and \\ill dischai'ge a negatively charged body, or \ri . ' . , charge to an uncharged bodv. Tin- reverse effect i- prod ici . ;in elect ric arc is passed t h rough hydrogen. l'i, ! , ninl \n*ses through the air ton plate. 1 _: ol 7 micro-amperes and t he point po^it ive, the number of positivi - 'J.'iH time- more than the neu.ati\"e ion- ' i -' - .'. ari-e from llames are electrified and are conductors of i [)o-itive and negative ions are to !>< found in a flame; 1 he.-e make a Halm all excellent conductor ot electricity. I'hv-. I'cv., xxxiii. I'M I . TO. TRANSMISSION OF ELECTRICITY THROUGH (iASKS 045 Steatn arising from electrified water is not electrified. Vapor arising from boiling mercury is not electrified, no matter how strongly the liquid mercury may he charged. When a jet of hydrogen is burned in the air the unburned hydrogen in the jet is negatively charged. Lavoissier and Laplace as long ago as 1~S-? noted the fact that hydrogen rapidly liberated by the action of sulphuric acid upon iron possesses a strong positive charge. According to J. J. Thompson's observation, the presence of an electric charge upon a drop of water tends to prevent the evaporation of the water. C'rookes, on the other hand, has found that evaporation takes place more rapidly from the surface of water which is negatively electrified than when the water is not electrified. Mascaret's observa- tion is that either positively or negatively charged water evaporates faster than water which is uncharged. The possibility of error in these observations lies in the lack of uniform conditions as to the humidity and the temperature of the surrounding air and as to mechanic cur- rents in it and in the lack of uniformity in the conditions which would ionize the air and influence its electric conductivity. If the air in con- tact with the surface of the water were ionized it would receive a charge of electricity from the water and be repelled from it, giving place to a fresh portion of air. which in its turn would be charged and repelled. Kach portion of air would, of course, absorb more or less water and the result would be a more rapid evaporation than the nor- mal, just as if a current were produced in the air in any other way. Then 1 are many ways in which the air might become accidentally ion- ized to a sufficient extent to affect the result in an experiment of this kind. THE PASSAGE OF ELECTRICITY THROUGH A VACUUM If the air or any other gas in a glass tube be partially exhausted by means of an air-pump, and there are two wires leading into it, the phenomena observed on connecting it with the source of high potential electricity may vary with the degree of exhaustion. Before the tube has been exhausted a discharge will take place through it as a xigxag spark passing through it from one wire to the ot her. and t lu 1 same is true of a tube in which t he ii'as has been exhausted, but into which air ha> entered in consequence of a leak or a puncture. Such a stale of things sometimes occurs with an .r-ray tube, and it indicates the presence of so larire a \> ak : ! .::; no amount of regulation of the vacuum will be effective until the opening has been found and sealed up. The discharge through a tube in 'his condition does not differ illy from that which takes place through the open air, and as in the latter case the distance across which the discharge will pass is strictly limited to the number of inches which corresponds to the voltage or the difference of potential o! the two poles. '1 lie spark length which certain voltages will produce is variously estimated and depends partly upon the .-hape and material of the discharging sur- faces. A spark 1 inch loirj; throuuh the open air. or in a lube- tilled with air, requires ai the least a potential of 10.000 volts. r>4i MEDICAL ELECTRICITY AM) RONTGEN KAYS A vacuum tube exhausted to the C I eissler degree of , , l \, ( . atmosphere does not become luminous on the passage of a continuous current, no matter ef what tension. The moment the current is made inter- mittent or alternating the tube lights up. The illumination also takes place if tin 1 tube contains mercury vapor or certain other gases. A tube exhausted to this slight degree becomes filled with reddish, bluish, or violet liirht when the high-tension interrupted current is turned on, there bein^r no visible or audible spark passing through it, and this li^lit is more or less st rat if led, seeming to pass 1 h rough the tube in waves. < leissler tubes (Fiir. 394') of different shapes were favorite laboratory toys and. were the forerunners of the Crookes tube and of a modern focus .r-ray tube. A tube which becomes filled with bluish or re 1 1 4 ;sh liii'hr allows the cathode si ream to pass directly from the cathode to the anode and does not present as great resistance to the passage of electricity as one with a higher degree of vacuum, i, c., from which the iras has been more completely removed, and it does not generate a useful quantity of .r-rays. The study of all the phenomena caused by the cathode rays has been more successfully performed upon the tubes with a higher vacuum. A Crookes' tube is a glass tube containing an almost complete va- cuum of about f7]i,y UO Q atmosphere. Crookes' theory in regard to a tube exhausted to this degree was that the molecules were so few and far between that they could move from one wall of the tube to the other without encountering other molecules. This is the ultragaseous state of matter. It was formerly believed that the cathode ray consisted of molecules of the residual gas, but it is now thought to consist of particles of matter, perhaps only one- thousandth the sixe of an atom torn from the atoms and thrown from the surface of the cathode. Such a tube offers great resistance to the passage of electricity, and even with a source of very high potential will transmit a current of roily a few milliamperes. If its two termi- nals are simple wires leading into the tube not much change may be noted, on turning on the current. There may be a little fluorescence 1 of the glass around the negative pole and this mav be of the greemsh-vellow tint which is excited in ordinal'}' lilass bvthe cathode ray. This is apt to be greatest around the cathode or negative wire. The rest 01 the tube may present little or no color, there will be some heating of the glass near the two wires, and t near the cathode, es' lube of this con- inena t akmg place m it i li.-covery ot the ,r-ray. | ihi 'in imena produced .- in))' 1 a re p-sult s of t he material particles much at a nuhl amde to its The Cathode Rav.- this is often greate While a simple Crool I'V UnUSUal, 1 lie plielK i their Mud;/ led to the I- most important icii v t hroi i-h a ( rookes ij-obably a Stream < ven from the cat i 10 TRANSMISSION OF ELECTRICITY THROUGH GASES 647 surface and carrying a negative charge of electricity. The other hypoth- esis that the cathode ray consists of vibrations in the hnniniferous ether does not explain many of the phenomena as well as this corpus- cular theory. According to the theory adopted in the present work the cathode stream of material particles proceeds from every part of the cathode at a right angle to its surface, and without regard to the position of the anode. The cathode stream is invisible, but its presence can be readily demonstrated to the eye by the fluorescence which it will excite in various gaseous, liquid, or solid substances placed inside the tube and by the mechanic motion which it will produce. Sometimes in an .r-ray tube if t lie vacuum becomes very low the visible fluorescence produced by the passage; of the cathode ray through the gas can be seen as a bluish streak passing from the cathode to the anticathode. If the cathode consists of a straight rod or wire pointing toward the anode, the cathode stream will proceed chiefly from the lateral surface of the rod. since that is of greater extent than its end. It will cause motion in a little wheel made up of several vanes or fan-like disks revolving on an axle in the same way that a current of air or water produces motion in a wind-mill or a water-mill. The best arrangement is to have one surface of each vane covered with polished metal foil and the other surface roughened, or a shield may be placed so that the cathode stream can strike only the vanes on one side of the wheel. The unopposed impact causes the wheel to rotate. The same motor effect can be pro- duced in a tube in which the cathode is formed by a disk or a concave circle of metal, as is the case in an .r-ray tube. This directs the cathode stream toward the particular spot desired to influence. The luminous effects of the cathode ray are seen in the fluorescence it excites in the glass wall of the tube, and this is of different colors with glass of different composition; for instance, glass containing a large percentage of lead changes to a beautiful blue, while the ordinary glass assumes a yellowish-green tint. If a solid object such as a glass or metal disk or cross is placed in the path of the cathode stream, a dis- tinct shadow is cast upon the wall of the tube. Beautiful effects are seen when various substances are introduced into such a tube. Under the influence of the cathode ray the following substances show phos- phorescence with the specified colors: CuSO, CuSO - MnSO St-SO, - MnS< ), ......... M:iS() ..................... HiiSO, f MnSO, . M-So' t ................... M--M \ - 1 PIT cent. MnS< >, Y.n>( ), .................... \a,S( ) ( - ()..") per cent. MnS( ) (MSO, .......... CaFl .......... Cnl-T i Mull, upon what Thomson ca MEDICAL ELECTRICITY AND RONTC.KN RAYS df electricity is due 1 to the published works of Professor J. J. Thom- son of Cambridge University. England (The Discharge of Electricity t hrouu'h ( lases) . These "solid solutions" arc formed \vhcn two salts, one greatly in excess of the other, are precipitated simultaneously from a liquid in which both are held in solution, the familiar barium platino- cyamd of the lluoroscopic screen for x-ray work is an example of a " solid sohll l< HI." The cathode stream travels at the rate of about 'JO. 000 miles a second and in a straight line, from which, however, it may be deflected in a variety of ways. It is arrested by the glass wall of the tube, and a thin sheet of glass placed within the tube and across the path of the cathode stream casts a very dark shadow contracting with the fluores- cence of the wall of the tube. Gold-leaf is less opaijiic. A sheet of aluminum O.OO'Jti") millimeters thick forming a window in the wall of the tube will allow the cathode ray to pas-; through it in sufficient amount to produce visible light and to cause phosphorescence in bodies outside of the tube. Experiments, with a great variety of substances have shown that the most phosphorescent substance is a piece ot tissue paper soaked in a solution of pentadekylparatoleketon, The cathode rays suffer diffuse reflection when they fall upon a surface, whether it be of an insulator or of a conductor. Cathode rays start in all directions from such a surface, especially if the rays have struck it obliquely. And the substance struck generally becomes itself a cathode and emits cathode rays, principally normal or perpendicular to it.- surface. These reflected or secondary cathode rays occur inde- pendently ,,]' il u . existence of x-rays, the latter are ethereal vibrations, while the cathode rays con- sist of particles of matter. The cathode stream under- goes no regular refract ion. but it may be deflected from its si raight pat h by a magnet . 1)> /!/,'(,// of /he ( 'aUiotlc S(t' atn 1 1 his is t he case wit h t he ] tsit ive ( ir neirat ive pole or I n it li poles, as in t he case of a hi >rsesh< >e magnet . -covered a magnetic spectrum in the cathode stream, mi; more deflected than other.-, and the result being ho-phorescence instead ot a single spot. ; that tin- was due to inequalities in voltage in suc- t'rom an induct ion-coil, a n< 1 that it does not occur with tatic machine or troni a large batterv of th 1 \\ o cathode- so heti they leave the -1 re a Ills will I ' found to repel each iveri: + y c ^\ .< upon a cathode stream. They are repelled to a portion of the tube where the magnetic held is weakest; there they become dissociated and an accumulation of positive ions is demonstrable. The .r-Ray. When the cathode ray as a stream of material particles traveling at the rate of 20.000 miles a second strikes any solid object. such as the glass wall of the original ( Yookes tube or the platinum disk in the modern /on/s .r-ray tube, the impact gives rise to the ethereal vibrations known as the r-ray. Were particles as large as pebbles to bombard any hard surface at a tremendous velocity the effect would b<- vibrations in the air which would be perceptible as a deafening noise. In a vacuum tube the moving bodies are only one-thousandth the size oi an atom and the f. In Un- original type there- were two leading-in wires and the- whole bulb became- filled with colored liirht which was more or less stratified. This light could be 1 concentrated at one spot if the finger was applied to the- side Fig. 397. A'-rav tube. Fig. 3!)S.- t.ieissler tube, showing cathode stream. of the- bulb (Fig. 398) and the finger then received a slight discharge of electricity from the surface 1 of the glass, from this early type have been evolved the- vacuum electrodes which form such an important part of high-frequency apparatus. A glass bulb with a suitable stem (Fig. . 309. Cieissler tube for use as a vacuum electrode. Insulated handle. ;W.>' ; and e'xhausted to the proper decree may be excited by connection with one pole of a static machine, .r-ray coil, or high-frequency apparatus. This does not re-quire- the 1 presence of any wire 1 at all leading into the tube 1 , and if there is none, the elect rifica t ion of the 1 enclosed gas must take place 1 by a sort of condeMise-r action. The metal handle is charged from the 1 static machine 1 , we will say. and induevs in the 1 gaseous c-onte-n;,- a ti.Y2 MEDICAL ELECTRICITY AND RONTGEN KAYS charge through the u1ao -troiiii a charge of electricity to excite it. The color of such a nibe varies with the degree of exhaustion, the kind of gas contained in it. and the composition of the glass. Such a tube may be made long and ; into a flat -piral (Fig. 400) with leading-in wires connected with the two poles of an .r-ray coil, and gives a beautiful violet and ul'ra- violet radiance with very little discharge of electricity to the patient. Vacuum Tubes for Electric Illumination. The first electric light on record was reported bv Hawksbee two hundred years ago. It was .uiii tube which when connected with one pole of a frictional static machine {rave sufficient light to read large print by. lh'' pract icable vacuum tube lights at the present da\' all depend lorescence exciter] in the residual gas by the passage of an eject ri' 1 current through it. In the ('ooper llewitt lamp the current i- of the direct 110 volts. In the Moore lamp an alternating current of ~>00i) volts i> ii-i.-cl. In the Tesla h'Lili! the yolta.ire has been raised by a : . . ' i ransfi irmer. The ' <>": i- //-///// Itit/ifi \"]'^. 401 consists of a vacuum tube about 1 . ler and from '_' to I feet long. It contains a certain <: metallic mercury and. of course, i- filled with mercury Her i- M very pool' con d net or of elect ric it v when cold, and ii i- necessary either to tip (he lube and make a ction ot liquid mercury Irom pole to pole, or else to current of at least IMDii volts through it fi'om an ! ' I'll he;- ca-e I he I 10-Voll ci in' inuoits CU ITi 'li I l.- . . ore>c(-lice. ' >i ii i and ; i ii la t'L;er -; / 7'H i < ;, IM i h -[ < >\\ er. i . but not nen , ' ; power is con- lical ' II 1 dec! I'jc . ' . ; : , a n .peri - I - elli'Mi nc;\ i- ci tri'i '-poi hi'jh, in fact . ' . ' require.- oiil\ i \\ at 1 pel cahdle-pi i\\ (]', \\ hlle : ' '. a n ; p e re a n d 1 1 \- o 1 1 s , i \\ a't- per candh -power. Tin cat hode terminal ' I In : ! ' end o|' t he I ilbe. The ] lo.-il ive Tin I iopcr ! Ie\ I : (.;,- about t he Tin lidii TRANSMISSION OF ELECTRICITY THKOl.'GH CASKS Drills the spectrum of incandescent mercury vapor, it is rich in violet rays, and almost entirely lacking in red rays. It is not especially rich in ultraviolet rays, as tested l>v \\illeniite. A verv interesting observa- tion may he made with the spectroscope in connection with this lamp described m the next paragraph. Nature of Fluorescence. Fluorescent substances have 1he prop- erty of intense absorption of light at their surfaces and of slowing tin- rate of vibration of light falling upon them. In the case of the mercury vapoi 1 light a piece of cloth saturated with a solution of a fluorescent substance like rhodamin, and dried, mav be wrapped around i he luminous Tube. Red lines and others not in the mercury spectrum \vill immediately be seen with the spectroscope. It is in t he same way that \\ ill emit e slows up the vibrations of invisible ultraviolet light and changes it to a bril- liant green. Something of an analogous nature must take place in con- nection with the ionization of the air by the ultraviolet ray. It will be remembered thai the ultraviolet rav ionixes a u'as and renders it a con- ductor of electricity and capable of discharging a cliarged body onh when the light is reflected from a fluorescent substance or from a metal immcrsei lint he gas. The Cooper Hewitt light, of course, does not give the natural color to objects illuminated by it. lied objects appear blue or purple and every little capillary in the skin and the entire mucous surface of the lips appears bluish. The visible effect is as it the person were dead and decomposition had begun. While it is not suitable for general illu- mination, excellent photographs may be made by it. either originals or reproductions from others. It is made up almost exclusively of the most aclinic ravs of visible light and on ihis account has seemed of value to the present author in the treatment of tuberculosis by light baths. The uviol lamp is made of glass which transmits a greater percent- age of ultraviolet rays. The eyes, however, should be protected from a light so rich in ultraviolet rays. Moore's Vacuum-tube Light.- Tube.- of an}- length ma}- be used and passed from room to room, distributing the light just like the steam- 054 MEDICAL ELECTRICITY AND KONTGEN RAYS or iias-pipes. They are connected at a central box in the cellar or else- where with the alternating current of 110 volts, or with the 110-volt direct current modified by the use of a vacuum-tube rotator, producing extra currents by its sudden breaks in passing through an electromag- netic coil. Kit her of these currents is passed through a step-up trans- former, raising it to 5000 volts. Any kind of vapor may be used in the tubes and light of any desired color and spectrum may be produced. Daylight may be imitated very closely. The light is accompanied by very lit t le heat . The Nikola Tesla Vacuum-tube Light. This is produced in a vacuum tube of any length by charging and discharging a condenser and passim: the discharge through the primary of an induction-coil. The secondary current thus obtained is of very high voltage and fre- quency and can be used with tubes with or without leading-in wires. Disruptive Nature of Vacuum-tube Transmission. A discharge of electricity through a gas which has been ionized can. it is true, take place by simple conduction, as in the apparatus employed for testing the radio-activity of radium salts, or in testing the quantity of the .r-ray bv the rapidity with which a charged electroscope becomes discharged, but such a transmission of the current is as free from any special phenom- ena as if the charge were conducted by an equal length of copper wire. The discharges through 1 he vacuum-tubes which have just been described are essentially of the nature of sparks or disruptive discharges breaking through the gas. not carried bv it. Still the same ionixed gas will also transmit electricity in the silent and invisible manner characteristic of true conduction. A Cooper Hewitt lamp, for experiment, may have a couple of leading-in wires at opposite sides near the middle of the length of the tube, and these two opposite wires may be connected with wires leading from a galvanic batterv of one or two cells. A galvanometer placed in the circuit will show that no current passes through the battery circuit until the Cooper Hewitt light is turned on. and the rarefied gas In-' ween i he t wo wires coming from the bat t cry and leading into the tube is ionixed and becomes a conductor of electricity. A cln i/iiciill// (ictirc fur-in of in'tro'icii is produced when pure nitrogen ga- i- u>ed in a ( ieissler tube and an elect ric discharge takes place through it. The explo.-ive distance in vacuum tubes is increased in a magnetic held parallel with the space, and there is a best .Mrength for the field. 1 A tube may light up in a field of 1 KM) gauss and become dark in a field of ill Hid gau>s (electromagnet with a current of 1(1 amperes). Cc.uv.r. H. l. l!H(), i:;20. PHOTOTHERAPY LIGHT as a therapeutic agent has become very prominent during the past few years, and its action is due to the luminous rays, the cheinic rays, and the heat rays. It was thought at one time that the heat rays were confined to the infra-red and red of the spectrum, but it is now known that there are heat rays through the entire spectrum. The cheinic rays were at one time thought to be confined entirely to the blue and violet-blue portion of the spectrum, but it is now known that they also are found throughout the entire visible spectrum. The heat rays found in the infra-red part of the spectrum are invisible. Temperature oj Incandescence. DKCKKKS FAHRENHEIT. 1000 Kod rays. 1200 Orange rays. 1300 Yellow rays. 1.100 JMuc rays? 1700 Indiiro rays. 2000 Violet rays. 2i:!0 All colors = white lipht The intensity of the light increases faster than the temperature. IMat- inum wire at 2000 F. gives out fortv times as much liu'ht as at 11)00 F. The temperature of the voltaic arc is about 3000 C. for the positive carbon and L'oOO ('. for the negative. In addition to the ordinary cheinic rays which accompany the visible rays of light, there are what are known as the ultraviolet rays: these are beyond the violet and are also invisible. An illustration of what are known as infra-red rays is The heat effect noticed when the hand is brought near a stove in which then 1 is a fire. These rays are more pene- trating than I he visible rays of the spectrum. The strength of light varies inversely as the square of the distance; this is an important law to remember: t lius. if at a distance of '.}() inches t he candle-power is ")()(), then at a distance of (10 inches the candle-power will be only one-quarter, or r_'.~> candle-power. The usual distance from the filament at which the candle-power of an incandescent lamp is measured is .'->0 inches, so that it" the patient is at this distance from the filament, the full rated candle-power of the lamp is being used. Another point to remember is that liirht is most effective when it strikes the surface at right angles. In order to compare different lamps an actinometer such as is used by photographers can be placed on the patient. In order to use this cor- rectly, all other light must be excluded. 655 MEDICAL ELECTRICITY AND RONTGEN KAY8 TIII: ro.Mi'LKTi: SIM-XTRTM OF LICHT Hrat J liavs. 1 'I'ri-ultra-rcd. Wave I.ciitilli: Very lonj. Tri-ultru-rcd. \\ ;i\'c Lcntit h : is micniM>. (ELECTRICITY ?) ritra-rcd. \\ avc Lentil h : s micron.-. Rod. \\avr Lcnglli: .71 micron \\ avc Length : .(>(> micron. Yellow. Wave Length : .()!_' micron. ( irceii. \\'ave I,en//<((> xccuml equals tin* effect produced as above* in one second at a distance* of 1 meter. X. 1). In applying this photographic measurement to .r-rays or radium rays, in comparison with incandescent electric light, the film .-hould be developed in the regular i ray-developing solutions for ten and in complete darkness. The Tests Which are Applied to Electric Lights, Either Arc or 058 MKDICAL KLKCTHICITY AND RONTGEN KAYS Incandescent Lamps.- In the case of an incandescent lamp it is of importance to test its resistance when cold. For this purpose the \Yheatstone bridge and the current from one or two voltaic cells are employed. The process of testing a lamp at work employs a voltmeter on the principle of an amperemeter of very high resistance for measuring the difference in potential between the lamp terminal-. The lamp may be any sort of an electric lamp: incandescent, arc, or vacuum tube. An amperemeter is also required for measuring the strength of the current, which inay be turned on or off by the key. A storage-buttery or a large batt'Ty of voltaic cells may be used instead of the dynamo. Thi- number of candle-power produced by the lamp must be tested by a suitable photometer. One of the simplest and most accurate is familiarly known as the grease-spot photometer. A sheet of paper with a grease-spot in the center is held up b< tween the standard candle and tin' liirht to be tested. Looking at one side of the paper the spot, which has been made partlv transparent, appears bright if the light falling upon it from behind is more powerful than the light falling upon the front of the paper around the spot. The paper is moved back and forth between the two lights until the grease-spot appears neither darker nor lighter than the sur- rounding paper. Both sides are examined to make sure of this. Then the distances from the paper to the stand- ard candle and to the lamp are measured and the num- ber of candle-power varies directly as the square of the distance at which equal illumination is produced. Thus, if the paper is four t lines a- far from the lamp as it is from the standard candle, the lamp is giving a huhi of If) candle-power. Knowing the tuonf/cr af \ he termi- t he following: Th ber of \\ ;; - per candle-pov :. I he higher i- the . and I"!' I he same ly] < !' !a mp I he ]e>s heal is iial i 1 ill. lor cyst oscopic and ot her endoscopic work rip- of hliih efficiency. ' ric h^ht bulbs have very hi^h efficiency; for 1 " 'V. > ' !'. i|' 1< l< I c.-| ). ;, till ( I. !.") Wat t per This j, because the filament i- ;it a hiirher temperature ' ordmarv electric Imlit buli>. The <^a~ retards PHOTOTHERAPY 859 the evaporation of the tungsten and convection currents carry particles to the top where they do no harm. The filament is in a compact coil so as not to he cooled much !>y gas currents. Fitl. 404. Treatment of patient with 100-candIe power lamp and paraholie reflcrtor. Incandescent Electric-light Therapeutic Lamps, The most com- mon type of apparatus for the application of light is an incandes- cent lamp mounted in some sort of a reflecting device. Figure 403 shows can he easily adjusted to any lamp outlet, and can l>e held either by the physician or, in some cases, by the patient. This style is useful 100. Showing u .-houldcr treatment liv clcctric-lijrht h:ith. PHOTOTHERAPY GUI in muscular pains due to cold, such as what is commonly known as muscular rheumatism. It is also useful in mild cases of neuralgia. Dif- ferent sixes of lamps of this type are made with incandescent bulbs of various power, and may be used with or without color screens and with different colored bulbs. Figure -t()") illust rates a slight ly more elaborate device for applying t he light over a much larger area. In this device there are ten incandescent lamps each of Hi candle-power. It is hinged at the central part so that it can be easily placed around a limb or over the shoulder. On the top of it is a selector switch, so that five or ten lamps can be used, accord- ing to the requirements of the case. Figure -107 shows an electric-light bath cabinet. This is arranged so that the entire body, with the exception of the head, is subjected to the influence of from forty to eighty incandescent lamps. On the outr- side of the cabinet is a switchboard so that various sets of lamps can bo used. Although the illustration does not slow it, there should be an arrangement holding two strips of colored glass, one of red and one of blue, so arranged that either color can be turned in front of the rows of incandescent lamps, or, if desired, turned out of [he way entirely so that 1 he phut white iiirht is used. I igure !'.".' show> a di Herein style, in u Inch 1 he patient is placed in a reclining position. The number of lurht- is ivu-ulated by mean- of selec- tor switches on the outside of the cabinet. Figure IK) illustrates a portable elect ric-liirht cabinet having a folding frame and curtains. Thi- makes a very convenient arrangement, as when noi in use it doe-, not take up am space. To thi- can be ea-ily added the red and blue glass screens. The patient feel> much more com- fortable than with his head fastened by a \vooden or iron cabinet. Figure 111 shows a combination cabine! m which are placed a number of incandescent lamp-, and on the outside are mounted three arc lights, the object of this arrangement beinir to obtain whatever benefit there MKDK AL i;i.i;< TKKTi'Y AM) Ro.NTCiKX KAYS PHOTOTHERAPY 663 may bo from the increased (luautity of chcmic rays which conic from an arc light. I0v.or220vo!h lamp \\'ith non-focusing reftortor. Figure 112 shows an arrangement lioldmjz; four 12o-cjin(llo-po\voi imps, so as to make up a total of ">()() candle-power. It is also arranged 004 MKDICAI. KI.K( THK ITY AND HONTCKX KAYS >o that in place of usinu; all the liirhts, any one or a combination may be used as desired. I itrures } \.) and 414 illust ra1(> an an'anji'enient by which a 500-candlc- po\\'er lamp is placed in a horizontal position so that the patient re- PHOTOTHERAPY Colored Screens.- "When colored screens arc used, ihev are generally made <>!' narrow pieces of glass held together in a metal frame (Fig. -11")). The object of this is to prevent breakage, as the amount of heal ab- sorbed in the glass would break it if it was made of one piece. Isolation of Calorific Rays of Great Wave-length by Quartz Lenses.' - The hot light from a Fintsch lamp passes through a circular opening in a metal screen, then 2(5 cm. further through a quart/ lens and another diaphragm and a second quart/ lens, all at the same distance apart. The lenses have 1 a focal length of 27. :> cm. for visible rays: their diameter is 7.f> cm., thickness at edge, 0.3 cm., and at middle, O.S cm.; diaphragms are 1"> mm.; the central parts of lenses are covered with black paper 2.") mm. The greatest wave-lengths are more highly refracted, and pass through the dit'l'erent diaphragms and may l>e demonstrated l>y a radi- omei er. \-'.\\ remely great wave-leniil hs up to )>()() mm. have been isolated by !!. Rubens and ( >. \'on Baeyer from the light produced by a merciiry va])or l.-mrp filtered through black paper. Electric Arc Therapeutic Lamps.- Fi- chemic rays, they use blue glas-e~. Th" appai'atus contniiKMl an electric arc which used SO am- peres; this has been improved and Hinplifi''d. the mo>i important modi- iication being one in v/hich practically all (lie heal rays ar< absorbed, -0 that the action i- due entirely to luminous j'ays.t lie cliemic ray ; ; which actMni))a.ny luminous ray-, and some ultraviol ' rays. The condenser is made- of (|uart /. \\ hich allows practically all of the ull ra violet rays to pass. The metal section i- filled with, water; the si ctioli nearest to the arc is arranged fora continual circulation of water. In addition to this. I )r. Finsen had s]>ecial compres>or> made of ()ua!'t/. which, were in iirm 1 II. i;ul>ms an.l I!. VV. Wood, Lc Hn.liiiin, Caris Feb., I'.M I. p. I 1. -' J.c UjuHuin, A])ril, I'.tlt. p. i:;<.'. 606 MEDICAL ELECTRICITY AND RONTGEN KAYS contact with the diseased area. These compressors were also either filled with water or arranged for a continual circulation of water. With a lamp such as is shown in Fig. 417 and which requires 2o amperes of current, the time required for a single treatment is one hour and ten minutes, and, as a rule, improvement is not expected in less than three months. Numerous modifications of this lamp have been made; with the idea of increasing its efficiency. 1'ig. 117 illustrates the latest improvement in the Finsen ray lamp. This is known as the Finsen-lleyn lamp. With this apparatus only one case can be t reated at a time, but instead of using SO or 100 amperes for the arc, the apparatus requires only 20 or 2"> amperes. It has an automatic arrangement for maintaining the arc and an adjustment, so that the length of the arc can be regulated. It is mounted, on a heavv iron pedestal ;md arranged with a counterweight, so that it can !>' ca.-ily raised or lowered and brought into the most convenient posi- tioti. In 'hi- apparatus the lenses are made of quart/, so lhat all the ultraviolet ravs which are generated ]>v the arc are transmitted to the pat iciil v. ii h vi-rv lit i le loss. 1'i'j. 11 s illustrates one of I he best form- of arc-light apparatus mad' in tin- country; all the adjustments are easilv made. The auto- inatic arratiL'i ment for maintaining the arc is particularly nice, and v no attention upon the part of the operator. There ndow so that the arc can be readilv seen without dis- oh-er\ er. This lamp is made to lake from 10 to )>() an i pi ' - . 'j ' > t lie special requirement s of the case. I In illustrate the three wavs in which the, rays can PHOTOTHERAPY 0(57 bo refloc'tod : Fi^. 419, a, shows the arrangement for focusing tlio rays upon a particular point; Fia;. 41'.), l>, sliows the arrangement to cause the rays to diverge; Fia;. 419, c, to throw all of the rays into one parallel beam. TIL'. 117. Iron Electrode Lamps. -It was found that by employing electrodes which we're made of iron instead of carbon the proportion of ultraviolet rays was very much increased, and a lamp of this style is shown by Fius. I'JO and l'21 This was devised by Dr. Bam:, and in order to operate it. it was found necessary to luive the electrodes and the entire casing arranged foi a cont inual circulation of water. \\ hile this deyico is yerv efiicient, it is a rather inconvenient one to use. MiX MKDICAL KI.KI TKKITY AND KONTCKN HAYS PHOTOTHERAPY 009 Fig. 422 illustrates a modification of the Bang lamp. This \vas devised by Dr. Henry (!. Pil'fard, of \<>\v York City, and its const rue'tion is such that no water circulation is required. Owing to the fuel that the arc: is only o inches away from the tissue to be treated, it makes a most efficient apparatus. Iron elec- trodes, however, cannot be used 3 on an alternating current, so that in order to use this lamp on an alternating current carbon elec- trodes which have iron filings in them are used. The carbon arc is not nearly so rich in ultraviolet rays as the iron arc, and this is very prettily demon- st rated by the following experiment : Place' a piece of solio paper in front of the carbon arc 1 for one minute. You will notice that it will become slightly discolored ; now place another piece of solio paper in front of the iron arc, and in the same time you will find that the paper has become absolutely black, this indicating that with the iron arc a greater proportion of chemic rays are generated. Tungsten Electrode Arc Lamps. violet light treatment then 1 is no form of apparatus which for cheapness, durability, simplicity, and efficiency can in any degree compete with a .. t -cooled -W. .1. Turrell 1 savs: ''For ultra- adjustable arc lamp capable of carrying 20 amperes, fitted with rods about 7 inches long and ] inch square, of pure 1 highlv compressed 1 . \IIHT. Jour. Eloctrotheranv and Radiology, vol. xxxvi, No. 4, April. 1918. (170 MEDICAL KI.KCTHU ITY AND ROXTGEN KAYS Condenser Spark-gap Lamps. One therapeutic and physiologic use of condenser discharges is in the production of visible and ultraviolet ray-. A Leyden jar '2 inches in diameter and with a total length of 10 inches may have one armature connected with one pole of an induction- coil or transformer regulated to give a spark about 4 inches long. The other armature of the jar is connected with the other pole of the coil or transformer. Besides the above connections an insulated conducting cord passes from each pole of the coil or from each of the Leyden jar armatures connected with it to each terminal of a series spark-gap made up preferably of iron knobs. The sparks are very much louder and mure brilliant than they would be if the discharge from the coil passed through the series gap unmodified by the condenser. The light is very rich in ultraviolet rays. Such a lamp has been made with magnesium knobs, but this metal vnlatili/es readily and a constant shower of howim_! that I here i.- a radiation the quart/ doe- not transmit. An expo.-ure of 1 ,' , ' - lamp produces a very mten-e hyperenna. Ultraviolet Kays of Exceedingly Short Wave-length. I 1 , l.enard and ('. Ham- < ive di-eoven-d rav- of les- than !() mil. wave- PHOTOTHERAPY 071 length in the light from a condenser spark-gap with a tremendously powerful current. They use an induct ion-coil, in which the primary is of copper wire 3 mm_ in diameter, around an iron core 110 cm. lonii and ',) mm. diameter. There are three layers of IWO turns each. The second- ary is divided into four sections, in each of which are 32 layers of copper wire 1 mm. in diameter, and there are 00 turns in each layer. The pri- mary will stand a current of 00 amperes for fifteen seconds. The primary condenser has a variable capacity of G microfarads. There is a Wehnelt interrupter with a nickel electrode and a jar holding GO quarts of liquid. There is a secondary condenser in shunt to the spark-gap. The spark- gap has aluminum terminals 7 mm. in diameter and are only O.X mm. apart. The current regularly employed is GO amperes and 200 volts. The energy at each discharge is 1000 times that of the uniform flow of an arc lamp. The light from such an apparatus is relatively weak in visible rays. bui very rich in ultraviolet ray-, especially those of the shortest wave- length, even as short as 00 mu. i Uraviolei rays have the properly of causing certain chemicals and minerals to fluoresce. The most con mon test for the presence of ultraviolet rays is the fluorescence they produce when falling upon a piece of Y\ illemite. When the tilt ra violet rays strike a piece of \V : .'.< - mite, thev cause a nm-t beautiful u'i'een fluorescence. In order to 0*2 MKIHCAL KI,i:< TKMITY AM) KONTCiKN KAYS determine whether the fluorescence is due to ultraviolet rays, it is only necessity to place a piece of irlass between the \Villemite and the source of radiation. If the fluorescence is due to ultraviolet rays, the l)-c;indl<-po\\ er liiiht when run bv the 110-voll direct current with a rheo-tat to reduce the current to 1 or ~> ampere-. I'iu'Ut'e !_'.") -hows this lamp in use in the treatment of a case of p u 1 m o 1 1 ; 1 1 ; ; I > i - 1 - . A IIP il this 1,-mip i- what i- known as the uviol lamp (Fiu 1 . 1'J 1 ' . Tlii l-o :i mercury vapor lamp, but in-lead of iis'mo' ordinary - one which will Iran-mil higher freipiencies of lion and in- of llie ull raviolel ray 1 haul he ordinary differs from the usual incandescent lamp in that the incandescent filament is not 1 Miinrh. Mcil. Work. I'M id. Xo. in. p. ,377, reviewed in Le Radium. April. I'.inti. - Dermatol. Zeit.-fhrit't, vol. xi, p. 77. 074 MEDICAL ELECTRICITY AND KONTGEN KAYS 1 i_'. i_',. The Kromayer lamp: n, Lamp ronnertion-pluK; 1>. current dirpetion-indi- [iluu c'iniic<'tii)ii; '/, tube connect ion; , winucd nut for fixiiiL' lamp in fork ij; f, luniii; '/. fork luinp-lloldfT (iii;i\ ! fixcil in an\ iio.-itioii) ; h , i. in- and i'l'-i foi r-n linn ivui IT; '. switi-li; /. rhc-ostal lever; m, line connection; /(. rlieostat i Han- . ui'l .Manufacturiim Co., Newark) PHOTOTHERAPY 075 enclosed in a vacuum, but exposed to the air. Apparently this lamp is going to be one of the most efficient of the incandescent style used for therapeutic purposes, as the actinic power is great and the heat is very much less in proportion than when the usual incandescent lamps are used. As this is also a new type of lamp, it has not been used sufficiently to give an idea as to what its ultimate therapeutic value will be; the only disadvantage is that it can only be operated satisfactorily on the alter- nating current at the present time. The heater coil of platinum wire alone transmits current at first and. becoming incandescent, heats the glower, which is a small rod of such materials as zirconium and thorium. This becomes a conductor of electricity when hot, but though its resist- ance is diminished, it is still so great that it becomes incandescent itself. Ultraviolet rays are generated by a Crookes tube or an ./'-ray tube, and a special construction has been devised by II. Bierry, Victor Henri, and Albert Kane. 1 The tube has a sort of pocket of quartz tubing in which substances may be placed very near the anticathode. Carbo- hydrates undergo the same changes as when exposed to the ultraviolet rays from a mercury vapor lamp. A burn appearing within twenty-four hours after an .r-ray exposure is doubtless due to ultraviolet rays gene- rated by the .r-ray tube. This source of injury may be suppressed by interposing any screen opaque to ordinary light. Effects of Ultraviolet Rays Upon Gases.- 1. There are produced uncharged centers of condensation which are due to impurities in the gas. 2. P>oth positive and negative ions are produced in the gas. 3. There may be changes in the gas itself, as when oxygen is changed to ozone. The effect upon chlorin has been especially studied by Ludlam.- who finds that the presence of a trace 1 of chlorin increases the ionixation of the air under the influence of ultraviolet ray-, but that above 1 per cent. the more chlorin is added the feebler the ioni/ation becomes. The t((trdrii>l( ( rni/x /'/< x>/nluj/il io)u'z( tin air, rendering it a conductor 1 ('. H. v I Met on, of .\ i 'W Orleans, almost a cent urv previously, i i very much better when the ordinary luminous i! the patient. Till.- was accomplished by mean- of al-o cut off most ot tin ordinary chennc ray.-. In order he ''if of different color- the iilass of \\hich the mcan- ratl be of the desired ci >1< if. - if a glass of the placed in fn ait of the incain le-cenl lamp, which is inal light : it simply cuts off all ot her color-. It doi no' io tely. but it does -o for all pract ical purposes, and tin- a'''i ii - i-- placed in front of the li-ht \vill be just the same a- thoiiu'h '!.' incandescent lamp \\ere made o| blue gla-s. 1 i'i,\ - /. .-I , . i:;, I'.u:;. L'UT. - \\ . [;. Mn _ 'I',',- ill I 1 ), i itm :.< J.Hir. f.l Sci, ncc, v, L' 1 -'."), 1010. PHOTOTHERAPY 677 It is a well-known fact ihat light favors oxidation outside of the body, and as it penetrates the body it should and undoubtedly does promote oxidat ion and chernie changes in the fluids of the body. Ac- cording to Freund, light is capable of changing a passive congestion in'o an active one. so that light is indicated in chronic congestive con- ditions where 1 the light can be applied in sufficient power. Chemic Effects of Ultraviolet Rays.- I'ltnivielet rays bring about loss of nitrogen in certain cheiuic compounds and in others the reverse, changing nitrates to nitrites or vice versa. 1 I'll raviolet rays change starchy solutions into maltose and dex- trin '' and, according to the same experimenter, inulin is changed into glucose and levulose. Ultraviolet rays destroy the properties of diastase in solution. Kay-; of a wave-length greater than M022 Angstrom units do not have this effect, 3 Effect of Ultraviolet Rays Upon the Digestibility of Milk. A short exposure has no effect, a longer exposure lessens tryptic digestibility, and a still longer expo-mv restores it. 1 ritraviolet rays change saccharose into glucose and levulose: their more prolonged action produces formaldeliyd and carbonic oxid." I'll raviolet rays from a (juartz mercury vapor lamp change a .-mall proportion of chlorophyll dissolved in alcohol and water into urobilin- ogen." I hraviolet rays, thi'ee hours and a half exposure, destroys the hemo- lytic action of saponin.' I 'It raviolet ray- destroy amylase and invertase :"m malt and yeast i ; the formei 1 is more sensitive, and in a mixture it may be destroyed and the invertin be only attenuated." Biochemic Effects of the Ultraviolet Ray.- {'lira violet rays in thirty minute- to two and one-half hour.- reduce the toxicitv of Stro- phant ines. ' I Itraviolet rays ([iiickly destroy the venom of the cobra, but have much less effect upon ant ivenomous serum. 1 " I Itraviolet rays have an effect upon the \\a--ermann reaction for syphilis analogous to their effect upon tuberculin. They do not effecl the properties ot -era rich in antibodies, hut antigen--; and antibodies no It inger lix alexins." ISaeteria killed by ultraviolet i - ays preserve their agglutinins intact, and can be used for serodiagnosis. 12 ].. Ma>>!, I!,!.].. 902. March 27 I ! .H1 ' II. Aiiiilhon, [hiil., :!9S. |Vh. |:;. i, C. i;. ,! I;, >,-. dc [iinl., Ixix. :i21. Xov. .'. I'.UM. H'-nri lii rr. Victor II, mi. and Allu-n H.-IIK-. lijid., lx\. 000, .!uti' 3, 1911. nii-l C. 1!. 'i" I'Ac.Mil. i!cs Sciences, [(>2U. Juno li. 191 1 (; II. P.ierry .uni ,). L-irfi'iiii r des li'incel-. C. \\. <]< I'Acrul. 1" \cadi inir des Scienci s, rlii. t ',2:1. March. 191 1. 078 MEDICAL ELECTRICITY AM) KONTGEN RAYS I Itraviolot rays destroy the antitryptic properties of human blood- serum.' Effect of Ultraviolet Rays Upon Anaphylaxis. Horse serum, ex- posed to the radiation for two and one-half to three and one-half hours, shows a destruction of its antisensibilitins without lo.-> of its precipitoge- nous proper! ies.- Effect of Ultraviolet Rays Upon Tubercle Bacilli and Tuberculin. A short expo-ure attenuates the bacilli in a culture and a lonti exposure kill:- them. Tuberculin lo-e- its properties, and this effect is more rapidly produced in the air than in a vacuum/' Effect of Ultraviolet Rays Upon Tuberculin and Antitubercular Sera. - It render- tubeivulin inactive, but does not modify its precipitogenous property. Serum, however, quickly loses its precipitant property. 4 Influence of Light in Causing Hyperglobuly at High Altitudes. The accumulation ot Mood-cell- in the peri pin ml vessels which ordinarily take.- place at hi tar back as 1S77 Downes and Blunt 1 experimented upon the bac- tericide effect of liirht and found that the mo>t refrangible was the most active. Ainonu' other- Houx. ( leis.-ler. and Mar-hall pursued further studies, which preceded Fin-en's \vork. The latter in IS',)'.* to 190"), with hi- ])upils. S. Baiiir. V. Bie. A. I.arsen. ('.. Dreyer. II. .Ian-en. (). .Jensen, ('.. Bu-ck. Schmidt-Nielsen, A. Heyn. and K. Kol-ter. -tudied the effect u])on yeasts. funii. ameba'. infusoria, and different animal tissue's. I in-en and hi- pupil- -howed .that our >unli^ht i- quite ]>oor in ultraviolet rays, due to absorption by the air. The arc li^ht is rich in ultraviolet ray-, and \\ilh the positive carbon 21 and the negative 12 mm. in diameter and M5 to SO amperes, \\ith an average of 50 volts. the liul.t beinu' concentrated upon a Mirface 12 mm. in diameter by a quart/ !cn- 7 cm. in diameter, and with the heat filtered out by a layer of water in a vessel with quart/ walls, tin- liuht kills the Bacillus prodijji- o-u- iii two or three seconds. Arc lamps with metallic electrodes, espe- cially iriiii. are maiiv time- more effective than 1 hose with carbons. The interpo.-it ioii of even a thin -heel of ula--. and the admixture of bouillon, pepton. albumin, uelalin. or any other oruanic colloids to the water, anv.-ts the maior ])ail of the ultraviolet rays, while perhaps perfei-tly ti'an-jjarent to the visible rav>. \ariou- nerm- >how different d<'Ui'ee> of -u-cepl ibilit y youiiu culture- are more sensitive than old OIK-. ;iiid the -pure- ,-u-c three to five time- a- re-i-tant a- the u'erm-. I'.i,; culture- of any of them may be -terili/ed by exposure to the ultra- violet ray. The time required i- from a few seconds to a few minutes. PHOTOTHERAPY 079 Those- oxporiments also showed that the effect was due directly to the light, and takes place in the absence of heat or oxygen. A later development dates from 100"), with the discovery of the sen- sibilization of animal tissues by means of substances like anilin dyes containing iodin or bromin, which is liberated in the tissues by the ultra- violet ray and adds to the effect. For example, a hypodermic injection of 2 milligrammes of hematoporphyrin into a white mouse produces no inconvenience while in the dark, but kills in three hours' exposure to arc light. And the final process consisted in the introduction of the mercury vapor arc in a tube of quartz, like Kromayer's, generating the ultraviolet ray much more powerfully than any of the open arc lamps. The therapeutic use of the ultraviolet ray is due to Finsen, Preisz, Seiffert, and others, who applied it to the sterilization of milk, and ( 'our- inont and Nosier to the sterilization of considerable quantities of water. It has long been known that the most rapid vibrations among the ultraviolet rays are the most active, and Thiele and Wolf 1 proved this by the use of a screen of blue rock salt, which arrested the heat rays, the visible rays, and the ultraviolet of a wave-length greater than 330 mu., but which was perfectly transparent to ultraviolet rays of a wave- length from 380 to 210 mu. Measurement of the Intensity of the Ultraviolet Rays. The in- tensity of the different wave-lengths generated by an ultraviolet lamp may be measured by a delicate 1 thormopylc and a quartz lens or differ- ently absorbent screens. A relative measure of the entire ultraviolet radiation is obtained by measuring the ionization of gases and electrifi- cation of metallic surface-; very much as radio-activity is measured. Becquerol's method, modified by Kder, is based upon the amount of calomel precipitated from a mixture of ammonium oxalate and bichlorid of mercury. 1 ' The sterilizing effect upon a twelve- or twenty-four-hour-old culture of colon bacilli upon agar is employed by Henri ( Vrnovodeanu and Henri (1. i'.). The bacilli are carefully scraped off without any lumps of agar and are emulsified in distilled water and exposed at a distance of 20 cm. from the lamp. This reaction is almost exclusively limited to the invis- ible ultraviolet rays, .and the interposition of a shoot of colorless glass 1 mm. ( ,,'.-, inch) thick makes it take 1000 or 2000 times as long to sterilize the emulsion of bacilli. An exposure of one second with a certain mer- cury vapor lamp with 140 volts and 4.7 amperes produces complete storilizat ion, while 300 seconds are required wit h 23 volts and 2.3 ampere-. The photographic effect upon nitrate of silver paper (solio matt' is employed by the same authors. This paper, when exposed to the light from a mercury vapor lamp, is chiefly acted upon by the ultraviolet rays, only one-eighth of the effect boinu due to the visible rays. The time required to produce an equal discoloration is inversely proportional to the bactericidal activity. A moans of arriving at the proper color of the paper is by comparison with the action upon iodid of potassium. Ilonri-( 'ernovodeanu and Henri place c.c. of ."> per cent, solution of 2.1 per cent . sulphuric acid in a gla>s dish. 3 cm. in diameter, at a distance of 20 cm. below the lamp, and determine the time required to liberate 0.1") milligramme of iodin. 080 MEDICAL ELKCTHICITY AND RONTCEN KAYS \\ater is very transparent to the ultraviolet ray. even more so than air. and through cither medium the time required to produce an equal effect increase- about as (lie -quare of the distance from the lain]). The bactericidal effect i- neither slowed nor hastened materially by the temperature at \\hich the ultraviolet ray is applied. In this it follow- ( ioldl >eru'- law reuardiim' true photochemic reactions. 1 This is entirely contrary to ordinary cheinic reactions, which art' many times more act ive at hi^h tempera t ure. The bactericidal effect of ultraviolet ray- i- the -anie whether the enml-ion i- a liijiiid or is fro/en into ice. providhm the latter is trans- parent . h was formerly -uppo-ed that the bactericidal effect of the ultra- * rays wa- due to peroxid of hydrou'en uvnerated by the rays, but bacteria are killed just a- quickly in the alenecoiids required to /e an emul-ion of ( : oioii bacilli and iind it to be an infinitesimal trace. I )i fie rent ( 'manic substances are variously susceptible to change under the influence of ultraviolet rays. (duco-e is much more resistant than levulose. and >ome fatly acid- are more quickly -aponified than other-. ancer cell- in mice are more susceptible than The normal cells. [(. VniovodeailU and Xe^re.) The \'isible effect iwith the ultramicro- in. M icn IH ii'ii-anHins ot consider- : " i in M o)!a-m i- c< (aiiuia i H -!/> . ra nieces, and I lie while Mood-cell- and I lie white ol eu;! all show thi- effect \\hen expo-ed to the ultra- mal cell- it)' all kind- are tixed by exposure to Thil-, the red blood-cell- no lonuer lo-e their heino- ii of wa ' er. The mien >he- are n H >re difficult to 'in-: and it the expo-ure ha- been prolonged, the ' ilai di-intenrat i' MI. 'Irani'- -taimnji no longer 1 ' rid re-i-1 ance of nil M T<-|I i lacilli i- li >-i . Sterilizatirin of Water and Milk bv the Ultraviolet Rays. Water, red ] icrfeci |\ t ran-parent 1 iy iilterintr, can be PHOTOTHERAPY G81 completely sterilized by passing through ;ui apparatus in which it must come in contact three separate limes with the quart/ plate separating it from the space in which a mercury vapor quart/ lamp is in operation. The lain]) in the apparatus shown in Fig. 430 requires a current of 72") watts ami will sterili/e loO.OOO gallons of water ])er day. Milk cannot be sterili/ed by the ultraviolet rays exce])t in such thin layers as to be t ransj)arent , and no very practicable apparatus is yet in use for thi- purpose. The Physiologic Effect of a Local Application of the Ultraviolet Ray. The effort is chiefly confined to the skin, and consists of an erythema with a papular swelling which often develops into a blister in t he course of twelve to twenty-four hours. The blister dries and when the crust falls off no scar is found. Meironsky 1 finds that the ultra- violet light stimulates epithelial cells and increases their metabolism, but strong applications cause degeneration and blistering. There is a congestion of the blood-vessels with emigration of leukocytes and extravasations of blood into the tissues. There is the increase in fibrous tissue cells already noted and a swelling of the connective-tissue si roma. A deposit of pigment granules may take place in all the different layers of epit helia. ( iranulating surfaces heal much faster li treated by ult ra violet light . Blood circulating in the tissues limits the effect of the ultraviolet ray to the most superficial layers of the skin. Fin-en blanched the skin by pressing a quart/ lens upon it, and other.- have injected adre- nalin or introduced the latter by electrolysis. Ultraviolet Light. Palms, soles, and scalp will stand, according to ( 'ora Smith King.- about twice as much as more sensitive parts. For treatment the scalp must be entirely denuded of hair by shaving or de- pilation. ('rusts and scales have to be removed. The therapeutic effects are to activate normal cell growth and function, inhibit ab- normal cell UTowth and function: also; 1, bactericidal: 2, oxidi/ing; o, analgesic: I, ant iprurit ic: ") soporific: (>, stimulating to granulating wounds; 7. markedly helpful to metabolism. Also 1, sens* 1 of "genial irlow" even through a water-cooled burner that would feel icy to the skin. Therefore the physical effect inn--; in 1 warming: 2, they "warm" to hyperemia and, with intensive dosage, even to the bli-ter- inn; point, yet without a -ensation of heal radiation. Ilyperemia de- velops in i wo to -ix hours and blister in seventy-two hours, luslowly declines, with desquamation, always without scarring, leaving new epi- dermis more delicate t han before, and hence i- popular t< >r co-met ic el'leci . ivjinmir the skin and causing coarse pores io contract and empty. This doe- not agree with the observed fact that a lady - -km may be of finest and permanently coarsened and somewhat reddi tied sun-burn which is due chiefly to ultraviolet ray-, brown, coppery brown, and finally mahogany: this is accompanied bv bactericide effect, curmu acne and boils. Sensibilization of the Tissues to Light. The tissues may be rendered more sensitive to liu'ht ravs bv the injection of substances like ervthrosin. This substance 1 render- the tissues sensitive to the rays, from the greenish-yellow to the yellow-orange inclusive, which ordinarilv do not affect t hi 1 tissues. The effect of a Fin-en treatment is 6S2 MKDK AI. KI.KeTKK 1TY AND RoNTCF.N HAYS thus obtained in one-fourth in one-thud the ordinary time. Dreyer 1 introduced the use of this substance following the experiments of Tap- peiner and Kaah upon proto/oa and animal tissues. The value of the method, however, ha.- lieeii -eriou.-lv (juestioned. Ko-in has been u-ed in ihe same \vav as er\'thi'osin 2 with favorable results in tubercular, syphilitic, and cancerous conditions of the skin. Siraiib'.- theory is that rosin generates hydrogen peroxid under the influence of light . Morton's nieihod of sensibili/at ion of the tissues to light and other radiations by the internal administration of <|uinin or fluoresein is still . and i he author'.- own observations do not confirm its value. Sonvntino paint- the surface of the lupus with an ar.-eniate. which seem- to allow the rays to penetrate the tissues, Forschhammer* used the following solution: Ti was injected ;}.">( I times altogether in I'M cases of lupus under phototherapy at Copenhagen. It produced no discomfort until the expo.-ui'e to the powerful li^ht took place, four to eight hours after the injection. The reaction to Finsen hidit was very violent, more lik>' a case of phlegmon than like the ordinary reaction after a similar exposure . Kxperiments with different dose- produced either no effect or a most violent one. The therapeutic effect seemed to be bad. The Effect of Ultraviolet Rays Upon the Eye. This is a subject which has been studied in detail by Birch-Ilirschfeld. 8 The rays in hi- experiment- were from a variety of sources; a powerful arc lamp with carbon electrodes; a dcrino lamp with iron electrodes; sparks from an electrostatic induction apparatus; sunlight. Quart/ lenses were used to concent rate the ra v.- in the eye. Tin- ultraviolet ray.- are laruelv arrested bv the crystalline lens, (his protects the retina from anv marked effect. An e\ e from which the crvstalline lens has been removed, for experiment or for the cure DI cataract, loses this natural protection. The especial changes from exposure to a powerful aic lamp under these cir- i - an- ;i loss of chroma! in in the ganglionic cells ami the tit of vacuoles in the protoplasm oi these cell.-. The nuclei - me ci I).- are large and clearly defined and have a vaeuolar a verv di-tiiici nucleolu.-. l.verv other part of the I'e' :. cted to a .-Ilidit extent. Ihese change.- ma\' be noticed a' oi i tak< i wenty-lour hours to develop. They are recovered I . . ! H i- , oi ill 1 normal eve to I he powerful a re lamp- used in phot o- ' : . ' ; ' e - a I - o important change.- i n all (lie ocular 1 1 1 e < h a except ':c- hicli remain.- ; r.-i i.-pa rent . I here are conjunc- cli iiidine-- of the cornea and part la 1 de-quaniat ion and soine- I). I ' / I-r-li., iV. N'.,. Id. '! : ii.l I<-ionek, Miincl,. M,, I. \Yncl,.. mo:!, \,,. 17. - III m;i] itti V.-li'T. i ilf||:i pi-lie, lilllti, No. 1 I ) ;' cl,. M, ,| \\orli., Sept. I,',. I'.KIi. An-li. i. Ht.I.tl u'ic. vol. Iviii n Ifi'.i. PHOTOTHKKAl'Y 083 times karyokinesis and vacuoli/at ion of Its epithelium; iritis and fibrinous exudation in the anterior and posterior chambers of the eye. These conditions disap|)ear after a few days, but slight corneal trouble, hypere- mia, and the vacuoli/ation of the ganglionic cells of the retina may remain for a long time. Sunlight is very rich in ultraviolet rays under certain special con- ditions. The reflected idare from snowfields upon high mountain.- in winter affords an example, and the eves often suffer in consequence. The ultraviolet rays in the blinding flash of light to which electri- cians are sometimes exposed from accidental short-circuiting produce important effects upon the eye. There is often temporarv blindness lasting a few minutes or a few hours, and sometimes there is ervthrop- sia: all objects, ('specially bright ones, appear red. After a few hours the conjunctiva becomes red and swollen with a feeling as if the eyes were full of sand. Keratitis and iritis develop. These conditions all disappear in a few days, but in some of t hese cases t here are also changes in the retina which may last for a Ion:: time or even be permanent, and which are perhaps not due to the ultraviolet rays alone. The effect of a stroke of lightning upon the eye is often very seven the crystalline lens may become opaque (cataract), and there mav be atrophy of the optic nerve or slighter nervous changes. These do not appear to be due to the influence of light alone. Ordinary eyeglasses protect the eye perfectly from the rays which are. strictly speaking, ultraviolet (beyond the visible extremity of the spectrum), but some of the visible rays near the violet end of the spec- trum produce similar effects. These rays may be guarded airainst by smoked glasses or yellow glasses, but not by blue glasses. The ultraviolet rays destroy bacteria in the eye either in front of or behind the crystalline lens, but the eye would be badly injured by the necessary length and strength of exposure. Cnnjiinctiritix Due to Electric Lit/hi. This occurs quite frequently amonii 1 those who regulate or repair arc lamps, and under conditions which make it evident that the trouble is caused by the light and not bv the heat rays. We believe also that it is due to the rays at the violet end of the spectrum and to the ultraviolet rays. The affection is only temporary and the treatment is by cold affusions of boric acid solution. More serious cases have been observed by Fuchs and are complicated bv myosis. slight opacities, and erosions of the cornea, but these also are recovered from in a few davs. Harold (Jrimsdale 1 has given detailed report- of several cases. One case was in a workman who had profuse lachrymation and redness and edema of the conjunctiva with several little papules, \ision was notablv diminished. He had repaired an an- lamp which remained lighted while he was working at it. Photo- phobia and i he other symptoms enumerate! 1 above had come on within a few hour-. Rapid recovery followed the use of cocam and cold at'fu.-ions of boric acid solution. Smoked glasses had to sonic t nne afterward. Another <>/ (rmnxduU '* CIIHCH followed an An engineer was arranging some incandescent ', occurred. There was a Hash of light lasting an exceedingly short time. The man felt blinded, but was able to see directly afterward. There was severe pain lasting for a few minute-, but toward night all the 1 I'IV>M- Medicale, April _'_', \W2. !)M MKDK Al, K!.KTKI< ITY -VXD HoNTCEN KAYS .-ymptoms had disappeared for the time. He awoke in the niidit, h' '.'. ever, with ail intolerable it chin.U of the eyelids, as if their mUCOUS sur- face \vere covered wit ll salld. There Was lachrymal ion. 1)111 no blepha- ro>pa>m or marki d photophobia. The palpebral conjunctiva was con- Li'eMed and covered \\iih papules. Yi-ion was iKH'iiuil. ( 'ocain and cold affusions of lioric acid solution ei't'ecie,) ;i cure 1!: I \vn da\'S. I'] e p resell i author oner pel-formed an experinieni in which a heavy the hand was used to -hurl circuit the 110- Ili'ect current. I'li'i'i \\'as a wonderful lla-h ot liLi'ht and about f tin sh-el \v: l; lly consumed : not merely melted, but [ di.--ipat ed. 'I he aut hor 's face was about 15 in dies from : [iroduced. but thei'e \\;;- no pel'Ceptible effect eves. I'nfortunat el\'. he is unable to recall \vliether lu- had at i he time or not. Plain irla.-s doe- not arrest mucli ibje li^'li? . but 11 does si op a ,i:reai pal'! of she iin'isible ultra- t rays. :,!L hly act inie. Physiologic Effects of Ultraviolet Ray Baths.- Those baths in . : ' : e the si Mii'ce of illuminai ion ui\ e the patient the oi t!n ultraviolet rays as well as of the liLiht rays and the at. The ei'fecl i- a vasodilator one upon the -kin and a reduction in li'en- ufhcient duration to make the apjilica- tinii valuable in many cardiovascular diseases, including angina pect(jris. Tin- I'jVct of an electric arc-liu'hl bath has been studied, principally in -elf. by lla.-.-elbach of the Finsen Institute of Copenhttli'en. 1 . Abril. r.MHi. formulate^ the i-e-ult- of tliese observations as _'. Ti - ma}' be c;ru>ed by partial paral\>is of tlie muscular walls i. I ' - wnes- of tlie I'; spil'atrivy moven ents is tjff>et by then' i h. -o that the amount o! per minute is the - i!,c:''-a-i ICIM 1 in o; :H !'-. ilat ion. much moi'e i i e- at 2 1 inchi's ! ront and 1 >ack < >\' "iik ' . ' con-i it u' ioiial -ympt< im-, . ' ormal t en i pi i a- ' on. a HOP PHOTOTHKKAl'Y Fi. 4:U. Straight filament incandescent lamp with parabolic reflector for concen- trated electric - liulit bath- f \Vulffs patent. Reini-rer, Gilbert A: Scliall, Elaugen). The Physiologic Effect of Incandescent Electric-light Baths. The most marked effects are profuse sweating and superficial va-odila- talion which increased tissue changes and lowered arterial pension. As commonly applied the effect is due chiefly to the radiant heat, but there is suffi- cient evidence that the light itself is a'so beneficial. The Temperature of Incandescent Electric-light Buthx. The statement is sometimes made that elect ric-light baths at about the temperature of the body will cause profuse perspiration in five or ten minutes. Experiments by Pariset 1 with different kinds of thermometers show that thermometers ex- posed to radiant heat in the open air register very differently (a difference of 31 ('.), according to whether the mercury bulb is a dull black or is of the usual polished glass. Even after fifteen minutes in a closed electric-light bath the two thermometers showed a difference of 9 ('. (about 17 F.). It is essential that the temperature the patient is exposed TO should be known and that the thermometer bulb should be blackened and should be exposed to the direct rays of the light at the same distance as the patient. Sweating may be produced by dark heat, but it requires a higher temperature and lacks the other effects produced by the penetration of radiant heat from a luminous source. It is not always necessary or desirable to have the electric-light bath closed up practically air-tight. It is sometimes pleas- anter to the patient to have the light bath ventilated so that the patient is not in as hot an air bath as in the other case. To make this equally effective the light should be concentrated upon the patient and not wasted in heating the walls of the cabinet and the air contained therein. An incandescent lamp with a long straight filament placed along the focus of a parabolic mirror (Fig. 431) yields parallel, not divergent, rays, which are directed toward the nearest surface of the body. All the light from a sufficient number of such lamps distributed uniformly over the surface of the body will produce the effects of light and radiant heat without the disagreeable effects of a hot-air bath. The temperature of the air in the ordinary closed electric-light bath- cabinet is about SO ('. or 177 F. The concentrated electric-light bath with ventilation causes perspira- tion to begin at a temperature of 77 F., and the maximum temperature of the air need not be over 112 F. A thermometer with a blackened bulb placed at the surfac of the body and directly exposed to the ravs Hill higher temperature. probably about 177 V. Treatment by Concentrated Incandescent Electric Light. Five hundred candle-power applied locally for about fifteen minutes is verv effective in sciatica, lumbago, dyspepsia, colitis, pruritus vulva 1 , rheumatoid arthritis, and cases upon the border-line between gout and neuriti^. Sonic of the latter have finger-joints which are red and shiny and >\vollen and exquisitely lender. The application should be Mrouu: enouuli to redden the skin and cause the patient to move about to prevent overheating, but not strop L: enough to bli>ter. Static elec- tricity is a valuable adjunct in the treatment of these conditions. l t'. H. ilo la Stic. cases of apparent mastoiditis cured by radiant light and heat. A few treatments by incandescent light removed the symptoms of pseudo-angina of his own heart ((!. Betton Masscy). Treatment by Red Light. This is effective in smallpox, where it prevents pitting, and in scarlet fever, measles, erysipelas, and noma. It is ordinarily applied by keeping the patient in a room where only red light is admitted. There seems to be reason to think that the .-ame results would not be obtained in complete darkness, that they are not due alone to the exclusion of the other colors, but that the red light has a specific effect upon the skin and renders n resistant to bacterial and other morbific agents. The cure of recurrent sunburn by wearing a red veil/ 1 and of ec/.ema by sunlight, while the affected parts are covered by red cloth, are along the same lines, freckles, seborrheic ec/.ema. and rosacea seborr- hu-ica have been treated by ointments containing a red pigment ( I'nna). Blue-light Anesthesia. The claim is made that blue light exerts a calmative and sedative influence and produces a sense ot well-being, and that fixation of the eyes upon this light for a few seconds produces insensibility of the face. This is said to permit of the painless perform- ance of minor operat ions, part icularly the extract ion of teet h. The patient's face is covered with a ll^llt blue veil; and there IS a Hi-candle-power incandescent electric-light In distance of aliout 7 inches. The patient looks or t h coin lit i< in t \v< i-t hir t hin and at the end of that time i.- usually t'< PHOTOTIIKHAPY ()S7 Blue-light Treatment. Blue spectacles have long been used for the protection of normal eyes from the excessive sunlight at the sear-bore and for the protection at all times of eyes rendered sensitive by some disease. Smoked glasses seem to do equally well and it seem.- pr< ibuble that the effect is due to the obstruction of a large proportion of the light, including practically all the ultraviolet rays rather than to the particular color of the glass. The effect of blue glass windows upon the growth of plants and the health of persons in rooms thus illuminated were studied some year* ago, but the method lias been abandoned. The Minin Lamp. This is an incandescent lam]) with a blue glass bulb and a reflector. Its effect is almost exclusively due to heat and is favorable in joint injuries and inflammations, and in eczema, superficial dermatoses, neuralgia, and rheumatism. Kaiser's method of blue-light (Ji< ra/n/ 1 employs a carbon arc lamp actuated by a direct current of 15 amperes and 110 volts, with a para- bolic reflector and a screen of strips of blue glass or a screen made of a glass-walled cell full of water in which methylenc-blue and a little alum are dissolved. The latter makes the best screen because it arrests most of the heat rays. The patient is at the focus of the rays about 2 meters ((> feet) from the lamp, (lood results are reported in tuber- culosis of the joints and of the skin (lupus). Itlnc-lit/ht iritfi moderate Jietit has been used by the author in the treatment of pain and swelling of the face from irritation of the nerve leading to a tooth. Such a condition may occur after a crown is applied, and if it is simply from mechanic and chemic irritation without infec- tion the author has seen it subside under this treatment. The lamp employed was a 32-candle-power incandescent blue glass bulb with a parabolic reflector. The face was protected by cardboard with a hole o inches in diameter which exposed the swollen cheek. The rays were not brought to a sharp focus, but concentrated upon the area, and the heat was entirely endurable, but still sufficient to redden the skin. Only one application was made, lasting ten minutes. The case did not progress beyond the stage at which the light treatment was applied, and in a short time the irritation subsided without having to remove the gold crown. How much the light treatment had to do with securing this result is a matter which the dentist (Dr. Gillett) is unable to decide. The patient herself did not think the light had produced much effect. Ill a< -lit/lit Butli*. ( leneral baths of blue liirht at a temperature of from lot to 122 F. and lasting for twenty or twenty-five minutes may be given every day at first and later every two or three days and each light bath may be followed by a hath in tepid water. They have a sedative and analgesic effect in such cases as neuralgia and rheuma- tism. Local baths of blue light in the open air. not a cabinet, have been found very effective in different cases of neuralgia. Albert -\Yeil'-' re- ports the cure of a case of severe intercostal neuralgia of two months' duration by fifteen treatments lasting ten minute- each: and in a ease of sciatica, in which other means had failed. Mue-liu'lit baths effected a cure in fifteen days. The apparatus required is a -^-candle-power blue glas- incandescent lamp with a large parabolic reflector. No. 4. !.">, 190."). MKDH AL i:i.]:( THK ITV AND KON'TOKX HAYS EXAMPLES OF THE THERAPEUTIC USE OF ELECTRIC ARC LIGHT I'ltraviolet liii'ht has been used in the t real nit-nt of ulceration of the cornea ami of conjunctivitis, and in treating .r-ray dermatitis. Tin ritmri.tli t l\u / in Lnconiotnr Ata.rin. Liebermann has reported beneficial effects from the ulti'aviolet ray applied alternately to the cervical, lumbar, ami the sacral regions. Improvement took place in 1 he pain am 1 1 he coon liliat n m. It* f*.s< /// /./*. This is extremely important ami is described on pa<:e (122. Elii'tric-lii/ltt htitlix with either incandescent or arc lamps are among the best means of treating rheumatism and gout and a variety of cardio- vascular affect ions. Ani/inn I'trla/'ifi.- Fifteen patients treated by .Tacobaous* showed the h 'Mowing results: 1 very grave cases showed some improvement, but latiT succumbed to the progress of the disease; :> old severe cases were improved and the severity of the attacks was reduced; in o milder cases the attack.- of precordial pain disappeared entirely, and this was tin- case also in ! moderately severe cases. That the effect was due to the treatment is shown by the recurrence of pain in '2 cases when the treatment was stopped and its disappearance when the treatment was resumed. Ila--elbach and .Tacobaeus 2 have pursued the same line of treatment somewhat further. They use powerful carbon arc lamps in the baths and obtain a dermatitis which from repeated applications becomes a chronic hyperemia lasting perhaps as long as a year and ma}' be accom- panied by a la-ling effect in relieving internal congestion and the like. Respiration exchanges are unaltered, but respirations become less fre- quent and deeper, inspiration being prolonged. A patient with cardiac distress breathes much more freely. Arterial pressure begins to dimin- ish after the third treatment. Both the diastolic and the systolic pressures are reduced, but the difference between the two becomes greater than before. The pulse-rate is unaffected. Dilatation of the ' is iisiiallv reduced during a course of treatment. Fifty ca.-es of various neuroses treated in this way showed great ' lent . ' hie hundred and thirty-one patients with chrome or organic heart- ii-easi \\ere treated. In some case- the valvular insufficiency was ed. but even then the sense of fulness and tension was hi'-ed nd so ,vere the dyspnea and pal pit at ion on exertion. Cardiac - M-nalh reduced; ! ! cases of true angina pectoi'is ga\'e .'.::i\ fa\'orab!e results \\iiich were (piite lasting. Combined Electric light Baths and Hydro-electric Baths in Obesity. The elect ric-liu'ht bath is followed by a general warm water . --P. ei\ cooled, whili a ' ' e i ime a sinusoidal i ' ' '. ' |( i 'o I _'( i ma. i- ajiplied through it for twentv to thirty ' of I In im i-1 effect ive modes ' if t :vat incut. I'att}' heart i- a cont ra-indicat ion to this treatment. Example- of the Use of the Mercury Vapor Lamp.- The author ' Cooper llev.i't lamp with benefit in a case of laryn- i uberculosis. A lamji of l.'n candle-jiowei'. to i- added the influence of a reilectoi' back of it. is placed horizon- bare che-1 at a di-taiice of ," or li inches from the TOTHF.KArY skm. An exposure of ten minutes reddens the skin temporarily. The treatment was combined \vith the use of the ./'-ray and high-frequency currents and resulted in the healing of the ulcerated vocal cord.- and a marked increase in weight, appetite, and strength. I-'inaiicial diflicitl- 1 ies then caused the patient to discontinue the treatment and she died of pulmonary tuberculosis about a year later. Xogier and Thevenot have shown bv 1 heir experiments 1 that applied 111 this way the light from the Cooper He\vitt lamp does not kill or ap- parently influence bacteria with an exposure of seventy-five minutes. But in a more highly concentrated form the mercury vapor light lias a bactericidal effect and may be used in the treatment of lupus ( Kromayer) , As an electric-light bath the light from the Cooper Hewitt mercury vapor lamp produces a general tonic effect, improving the appetite and digestion and removing insomnia. .Voider has seen long-standing cases of amenorrhea become normal under the treatment. He obtained satis- factory results in cases of anemia and chlorosis by combining this treat- ment with general measures. Locally, it has the usual analgesic effect of radiant heat com- bined with light, and relieves gouty and rheumatic and muscular pains. Pelvic pains of various natures are often relieved by applying this or similar lights over the hypogastrium. Xogier has shown by actual dynamometric measurement in 12 patienis that there is an increase in muscular power. Vttfuuin Jlul/ix of I'ui'c Qnnrtz. These can be made up to about 2 inches in diameter by fusing quart/ .-and with scarcely any other admix- ture. They transmit the ultraviolet ray perfectly and mercury vapor lamps so constructed are very active physiologically. The uriol lam]) is practically the same as the Cooper Hewitt lain]). hiii'h rates of vibration and hence more of the ultraviolet rays. The effect of the uviol lamp has not been fully tested, but it has been found to be very active superficially, and Pelli/.ari has not found it to produce as deep an effect upon lupus as the Finsen lamp. Dinijiiosfif {' si .< /if tin ('OOJHT Hnn'tt Lit/lit. The normal face pre- sents a strikingly unnatural appearance by this hirht which is devoid of red rays. Kvery red blood-vessel looks almost black and the lips are a dark purple. The skiii of the chest and abdomen may be examined in cases of suspected syphilis before the eruption: the latter beinu' visible bv this light several days before it is perceptible by ordinary liidit. In the same way at a later stage the eruption may be found after it is no longer noticeable bv ordinary u^'lit. The Cooper Hewitt mercury vapor lamp may also be used to watch for the earliest evidence of Kontgen dermatitis. Therapeutic Uses of the Kromayer Lamp. This light may be applied to the treatment of recent trachoma. ( >ne end of a quart/ rod is in clo-e contact wit h the quartz tube of the lamp, and all the liirht passes to the other end of the rod and affect- the ti--ue- without any lateral diffusion. Thi- i- a successful method of t reat ment. With the lamp at a distance of at least -1 inches from the -kin. an application of live to fifteen minute- i- effective in a wide raime of -kin diiotli indie-. The dosage in ec/ema i- one minute ,-it 1 il indie-, gradually increased at subsequent treatments to ;i maximum i >t five minute- at a distance of .s inches. Acne, ec/ema, and other di-ea-e- of the face ,-hould receive at fir-t one minute at 20 indie- Mini gradually increa>ed to a maximum of three minutes at the same di-tancc. ('In-mu:' the eyes protect:- them -ufliciently. M :i M\' uf the UK he; 1 1 ii in- for elect ric-liiihl t real men t in medical uyne- and - 1 : ! 'j II'M i ca-e- are met hv this lamp. Examples of Ultraviolet Ray Therapy. ( 'ora Smith Kirm re|)ort>< cure of lupu- eryt heniatosiis, tubercular inland- tor \\-hidi it is combined with diathermy through the neck laterally; chronic acid headaches with vomit niii ; dccji ero-ion oi cervix u-ini: t lie Kroma ver lamp t hroimh a speculum and al-o directly to cer\-|\ throu^li applicator on a long metal tube, ;d-o . \lpiin Sun Lamp to \\liolc trunk. Shmule- or herpes 1MIOTOTHKKAPY (> ( .)1 zoster were* cureel by twenty minutes of 1000 watt Ma/da and then two minutes of Alpine Sun Lamp at 24 inches. Four treatments were given in a week, but one treatment seemed to finish the disease;. Herpes o-f the cheek near the mouth and over the antrum yielded to one treatment of one minute with the Kromayer lamp ?, inch from lesion. Acne was cured by general ravin"' of t he body with Alpine Sun Lamp and close ray- in g of lesions with Kromayer lam]) twice a week, also colon irrigations for enormous retention stools, in a case previously treated by an expert with -ray. Neurasthenia was Driven three treatments weekly Alpine Sun gene'ral raying of trunk, at first two minutes. 24 inches, at each treat- ment one minute longer and one inch nearer, until fifteen minutes held there preceded by hot lamp to produce hyperemia, also colon irrigations. Bunion, three treatments in one week, Kromayer lamp, five, ten, and fifteen minutes. Pressure neuritis with callus at base of little toe, one treatment Kromayer lamp, 2 inches, five 1 minute's, another ten minutes thive days later. He'inorrhoids were 1 treate'd by a 2-inch quartz appli- cator insertenl into rectum and pre>sseel against the he-metrrhoidal arch, treating about one-third erf the circumfereone, four treatments, all to the 1 same area, totaleel thirteen minutes, burn subsieled in ten days. Insomnia, with mental dulness and baldness. Alpine 1 lamp 15 inches at first five minutes, but ineTcascd three minutes eae'h time (every three e>r four days) to keep scalp in a state of hype'ivmia, alse> gvneral raying erf trunk two minutes, 24 ine'hes, increaseel later. Balelness, case 1 erf complete 1 alopen-ia oevurring within one memth. Eczema erf leg, quartz window of Kromayer lamp presseel against skin for te*n te> sixty minutes, total ninety minutes, almost to stage erf blistering: this was the total erf five treatments in a few weeks, Care-inemia erf breast, lump four years' eluration, no ulceration, but some enlargement erf the axillary glands, e-olon irrigatiem, Alpine Sun whe)le trunk. Kremiayer lamp in contact with the bivast over the 1 lump anel ?, inch te> each siele. The lump was tivated only once a week at first, five minute's, ine-reaseel one to five 1 minutes up to thirty-five* minute's a sitting, blistering and exudation three 1 days afteT eae-h treatment, not painful, and patie'iit felt they we're doing ge>e)d; twenty treatments in all. Donalel McCaskey 1 says that a generalized ejiiartz light sun bath erf 8000 c.-p. for two minute's at 20 ine-hes etver the entire 1 nakenl boely as a first treatment would cause 1 prostration, chills, and fever, anel the patient would be 1 unwilling to have any more tivatnuMits. A sample 1 local applicatiem from a (jiiartz mercury vape>r lamp [it a distance ivporteel by Campbell 3 as having cuivd infee-tious osteomyelitis after ivmoval of >eMjiie>tra anel war with pus and -inuses involving boners, joints, or ce'llular tissue. Sunlight in the Treatment of Tuberculosis. A host of observations show that exposure of the part to the 1 direct rays of the' sun produe-es benefit in tuberculosis of the' bones and joints. Make a general ex- posure for three' to seven hours daily, watching the 1 ef'lVct upon the hemoglobin and red and white blood-cell-. Campbell 4 report- the cure of an apparently hopeless tuberculous spine and hip-joint. 1 Mc.l. Rroonl, October, Hi. l'.H7 2 Jour. Ainer. Mr,l. ASSOP., vol. 7'_>, No. !'_'. March 22. I'.U!). 3 I, <><. cit . 4 Amrr. .lour Siir^.. ,lulv. I'.il^. THE A'-RAY Disn iVKKKH by IIontLM'ti. in \\ur/buri:. April :>u. IVi.'). the .r-ray vvas something cm irdy new and not foreshadowed by anything else. I Ibnt _: -n was siudving tin 1 ("rookes tube and the cathode rav and had the tube sn thoroughly covered with black cardboard that no visible !l;j.'ht could escape into tile darkened room. lie noticed, none the less. thai a sheet of paper coaled with tmmstale of calcium be-all to emit liuht. He had discovered the .r-ray. a form of radiation which will pass '::'';_,'! substances opaque to ordinary light and produce luminous effects uj ii m cert all) object s beyond. It is a form of motion similar to light, tun with some trillion.- of vibrations a second and a wave-length a.- shun, sometimes, a.- ', cm. It penetrates solid bodies opaque to lidit waves and causes brilliant fluorescence in certain cheinic substances beyond. 'The /-ray itself i.- invisible. Our perception of it is due 1 to the luminosity of fluorescent substances which it shines upon. Differences in the Penetrating Power of Ordinary Light of Different Colors. F.ven weak blue light will through a blue solu-. lion and illuminate objects bevond. while the strongest blue liu'ht will be -topped by a solution of bichromate of pota.-h. The reverse i.- true of yellow li-'ht. Tlie ruby coloi-ed ^lass which forms the window of a photographic dark-room transmits the red rays of ordinary linht in sufficient abun- daiice to enable one to see object.- distinctly, but if a blue li.uiit were user! outside of the dark-room practically none of it would penetrate' l!i' ruby n'lass and the interior of the dark-room would be in complete obscurity. There are many other examples of substances which are t r; nsparent to ordinary liulit vibrations of a certain wave length and . ,' io others, Maiiv lances which are not transparent, still ai'e translucent. Th -1 if the hand i- readily -ecu through a piece of porcelain or a -hee; o! ','hite paper. Neither of these substances would serve as a for a sensitized photographic plate. The li^hi goes right A'ould fo.i! the plate-. 1 \ \ a i k pajier, however, absorbs lii liiihl and serves lo protect photographic plates ..'.'. Transpai'eiic\- io ordinarx' liLiht is like color, m ipon the arrangement of the molecule- of the substance mate r h e n i i c or atomic composition. Coal iamond. con.-istiim of aliout i-i|iially pure carbon. ireni to ordiiiar\' li^ht. A transparent solution of . it h a transparent nil will form an opaque emulsion. - tittle nr no part in n-^ard lo t rans] larency 1 1 < nd 1 ilack i ia| iei a re opai] n . \' hile Lilass. \\ hi'-h is - ra n-i ia rent . 'lien thai certain -ilbstatice- which are opaque to be transparent in the /-ray. which has quite a Difference Between the x-Ray and Ordinary Light. The ./-ray ter- ' - vend v n ordinar\ hull! m regard io it- penetrating '! UK ./'-KAY power. In ilic first place it is no! influenced by molecular arrangement , bill probably depends entirely upon the atomic composition of ihe sub- glance, and livnerailv, the jjrealer the specific u'ravitv, 'he more opaque the substance is to the .r-ray. Hooks ;md aluniinuin and vulcanized hard rubber are very transparent. (!lass is I ransparenl . but le in in. of lead is quite opaque. The .-all - of 1 he different metals u'ive very similar re-ult.-. whether solid or in solution. Absorption of x-Rays by the Air. Air ab-orbs about 1 per cent, of tho ,r-ray per decimeter H inches). Kveand Day 1 findtliat rays i'rom a very hard .r-ra v tube show mi absorpt ion of a I tout 0.0002"> lor each cent i met er of air, a medium tube 0.000 1. and a very soft tube I'rom 0.001 to 0.00 IN. These figures were true at distances of from ( to 10 meters. The rays reaching beyond I he latter distance showei 1 a lessened rate of absoiption. Tin' opacity i- not in direct relation with the density or specific gravity of the objects. If ii were so, a shee! of aluminum l> inches square, and thick enough to be as opaque as a sheet of platinum t> inches -quare ouii'ht to have the same weight. This is \-ery far from beinir the case. In one series oi experiment- by libntuen sheets of platinum. /me. lead, and aluminum were rolled until they appeared to be of almost equal transparency. The following table . 1 1 mm. of silver. Tin- i- the ba-ic ; rinciple of the Benoisi radiochroniometer. an instrument for measur- i':_- the quality of the ./--ray. Color has no influence upon transparency to i he .r-ray. and neither has the fact that the substance is opaque oi t ransparenl lo ordinary li^ht. (llass i- much less transparent to ilu; .r-rav than black paper, wood, or aluminum. Lcntird'x !.ni/ tl i/fii ill' In In : .r-Hays are not perceptibly refracied by Li'la-- ]>n-m- or b\- water or carbon bi-ulphite. 1'owdei'eil substances are quite as transparent to tlu^ 1 I'lui. Mai: . -''>, I'.iiL'. r,s:;. MEDICAL KLF.rTHiriTY AM) H()\T(iKN HAYS x-ray as are solid ho lies of equal mass. The x-ray cannot be concen- trated by lenses. No appreciable regular reflection occurs. Rood's observations in regard to the reflection of x-rays 1 seemed to indicate that ,,,',-,,, of the x-ray was reflected from a metallic surface which it strikes at an angle of 4") degrees. In the light of our present knowledge it seems probable that this small fraction of x-ray found in a region which it seemingly could only reach by reflection gets there either by secondary radiation or hy direct penetration through the interven- ing objects. Ordinary light may he made up of a mixture of different colors, but if separated by a prism each such colored beam of light is produced by a succession of uniform waves. The reflection and refraction of light are supposed to depend upon this property of regularity of vibration which is lacking in x-rays to a very great extent. A stone dropped into water starts a wave or eleva- tion of the surface of the water which forms a circle of constantly increas- ing size, and if this were only followed by other waves when other pebbles of various sizes were thrown into the water with different speeds the resulting waves would be analogous to those of the x-ray. Each wave of the x-ray requires a separate and distinct impulse and may have a different velocity from the one preceding or following it. Another reason why x-rays are not ordinarily reflected is that the vibrations are so much smaller than those of light that an ordinary mir- ror is as coarse to them as the surface of this paper is to ordinary light, which it partly transmits, partly absorbs, and partly diffuses. Diffusion in the case of the x-ray is by secondary rays. It has recently been ob- served that the x-ray is reflected to some extent from the cleavage planes of certain crystals which are smoother than most Mirfaces can be made art ificially. The x-ray spectrum is measured by reflection from a rocksalt crystal toward a photographic plate or an utilization chamber which can be placed at different angles to receive and measure the intensity of different wave lengt hs. Tip' intensity of the illumination of the fluoroseopic screen varies inversely with the square of the distance. The x-ray is not deflected even 1 iy a very st r < >ng magnet . Sir George Stokes' Theory of the Nature of the x-Ray.- The rays are due io a succession of independent pulsations in the luminiferous ether >?artmu I rom the points ot impact ol the cathode particles upon the ant icat hode. These are not con t unions vibrations like t hose of ordi- nary h^ht ; they are i-olated and extremely short. They are transverse like I ho-e o| huht and have 1 he same velocity . According to Sir Joseph 'I hom-on Lord Kelvin ihese pulsations are electromagnetic waves. Corpuscular Theory of the x-Ray. It i- believed by Bragg. Porter, and others thai the ./'-ray consists of material particles traveling at a very ' iuh rate of -peed. Most observers, however, believe that it con- si-t- oi . : lion- of i he iuminiferous ether. It i- interesting to note connection that ordinary light is deviated by gravitation. The h<_ r hi trmn a -tar pa--mir near the sun deviates about O.s second. PROPERTIES OF THE RONTGEN RAY THE X-RAY 095 causes the nil 1 through which it passes to become a conductor of elec- tricity, and in this way discharges a positively or negat ively charged body. It is itself invisible and does not produce the sensations of heat, light, or sound. When it encounters a solid substance it gives rise to secondary x-rays and to cathode rays, and while it does not itself carry an electric; charge, one is secondarily produced in bodies exposed to it. This is due to the ionization of the air, as explained later. The x-ray is not subject to ordinary refraction or reflection. Polarization of ./'-Rays. ('. C. Barkla has shown that primary x-rays and heterogenous secondary x-rays are partially polarized for certain directions of propagation. Some of the x-rays from the anticathode of an ordinary x-ray tube are proved to be polarized by an experiment which shows that the secondary rays arising from the impact of the primary rays are of a different quantity and quality, according to whether they lie in the plane of the cathode stream or at a right angle to it. The entirely polarized rays from an ordinary x-ray tube have the property of gener- ating especially rapid cathode rays. The non-polarized part differs only in degree about this. An aluminum screen increases the polariza- tion slightly. As far as our present knowledge goes the x-ray travels in perfectly straight lines, but on striking any solid substance a portion of the rays is absorbed, another portion goes straight through, and a third por- tion, or perhaps an effect of the other two, causes a diffusion of x-rays and cathode rays in every direction, so that everything in the x-ray room is affected by it. The only way to prevent a photographic plate in the x-ray room from being fogged, for instance, is to keep it in a closed box of thick metal. The x-ray consists of many different wave-lengths and these have different degrees of penetration. Different substances present more or less resistance to the passage of the x-ray and this ab- sorption is very closely related to the atomic weight of the substance. The greater the atomic weight the greater the resistance to the passage of the 1 x-ray, and this is true regardless of the transparency or opacity of the substance as regards ordinary light. Wood is very transparent to the x-ray, and so is aluminum, while glass is much less transparent and is more or less opaque in any thickness greater than -J, inch. The same difference in the amount of absorption is shown by the different tissues of the body. The lungs are almost perfectly transparent, and the .superficial fascia with its layer of fat. the muscles and solid organs, the bones and the teeth absorb the x-ray to a greater degree in the order gi'ven. The different degrees of absorption cause the x-ray which has passed through any part of the body to produce a visible image upon a fluorescent screen or a photographic plate. \\ e shall see further on that an x-ray picture is a chart of densities of the different tissues trav- ersed, and that next to safety the desiderata in radiography and fluoroscopy are great intensity of radiance and a quality of x-ray, which shows the greatest difference in the decree of absorption in passing through different tissues. \'t /// suft X-/Y///X are produced by an x-ray tube which is so constructed as to be excited by a potential of only '.'Oil volts. W. Sent/ 1 finds that different gases absorb these rays in different proportions, but not in any direct proportion to their atomic weight. For instance, for rays pro- duced by 1400 volts oxygen is very opaque and vapor of sulphur very transparent. 1 Phvs. Zcit., i:',. lUl'J. I7t>. b!t) MKD1CA1. Kl.Kc IKHri'Y AND RONTGEN HAYS The secondary rays ari-ing when t he .r-ray st rikes any solid object, or even when it pa.-.-e- i h rough tin- air, show evidences of being polari/able. llaga : find- that under appropriate condition- the secondary rays are five time- a- -t roiig in one plane as in another at right angle.- to it . This tend- to the conclusion that the .r-ray is due to transverse vibrations in the luminiferous ether. Characteristic Homogeneous Rontgen Rays.- These form part of the .r-radiation from the anticathode of a ('rookes' tube and have a uniform wave-length which is dependent upon the >pecific gravity of the anti-cathode. The heavier metals produce the more penetrating characteristic Kr>ntgen rays. Influence of Material of Anticathode Upon Character of Rontgen Rays. Tin 1 lo\\er the specific gravity, the more ab-orbable are the characteristic homogeneous .r-rays. There are always heterogeneous ./-ray- in add it ion which are not affected by t he nat ure of t he anticathode except as to quantity, being less abundant with a low specific gravity. Secondary ./--Rays and Homogeneous ./--Rays. A metal impinged upon by .r-rays gives out several kinds of .r-rays: Two kinds of .r-rays, one heterogeneous of the same wave-lengths as the primary .r-rays, and one homogeneous, characteristic ol the metal impinged upon and only excited by primary .r-rays of more rapid vibration^: also there are cathode particle-. They do not continue to be emitted for even ;,,',,,, second after the expi i-un ' cease-. The characteristic homogeneous secondary .r-rays are more abun- dantlv generated by impact upon substances oi high atomic weight and are independent of whether it is a pure element or a compound. ,). ( '. ( 'hapmaif has shown that the same characteristic homogeneous secondary .r-rays are produced when the substance is m ga>eous form. The impact ot homogeneous .r-rays produce's homogeneous and hetero- geneoiis -econdary .r-rays, and al-o secondary cathodic corpuscular rays. \\ hen .r-ra vs are sufficient ly hard to produce a secom lary homogeneous characteri-t ic radiation in one ot the element- pre-ent in a ga-. there is always an increase in the emission of secondary corpuscular rays, in the ab-orbent power of the gas for the ray- in que-tion and m the utilization product d by i hem in the ga-. : It is uncertain \\helher the major part oi 1 1 n i on i /a t ion o| a sias is produced by l he .r-rays I hem selves or by t he secondary cofpn-ciilar rays. Barkla and >imons' conclude from their experiment - t ha t it i- chiefly due to t he .r-rays. Produc 1 ":--,!! of Characteristic ./--Rays.' The cathode ((', Kig. I '.',:}> i- plane. The cathode mv- are about parallel and pass through a per- I oral ion ni tli'- anode into a -pace /, where t hey a re deviated to different I'jin iic held. / is a bra>s cylinder around which turn- it la 1 1 -i | ,t K. i \\ire carry a current in one fixed direct ion. producing ; < aiitu 'ic field indicated by M N. The voltage is varied until the \\ ill excit e Us cha ract en.-l ic rays, reach \ . an an 1 1- iterial to be le.-ted. Through the window i V\ ') of - practically exclusively the characteristic .r-rays. .lie ; c o!i ( m - i. '(iii! red are for: THK X-RAY LM'.OO volt: <),-_'()() 10,000 representing velocities of the cathode particles '2.X x 1() ;| cm. per second for ;diiininuin. 5.7(1 x 10' for iron, ;md (5.18 x 10' for copper. Characteristic Absorption of Heterogeneous ./'-Rays by Different Materials. Charles A. Sadler and A. -I. Steven 1 show that with an aluminum anticathode, a window of aluminum, 0.(HK>(>7 em. t hick arrests the characteristic homogeneous x-rays while transmitting the hetero- geneous .r-rays which may prove to have a certain penetration. Xow, increasing the thickness of the aluminum window, they find that the emergent heterogeneous rays have become softer, not more penetrating by the increased thickness of the aluminum. I'sing screens of different LT. !'>'!. Separation of .r-ray- into different wave-lentiths l>y a mairnet ic field, M to iiidarv u'-ruvs ai the accessory anti- X. and production ol characteristic homojreiieou ii li. ide, V. \\ i.- an aluininuiii window I ivvond \\ Inch an electroscope detects 1 liese ra\ materials they find that heterogeneous rays which have passed through ii'oii have become more absorbable or softer for aluminum than the heterogeneous rays from 1 he same tube without tin- interposition of the iron screen. The theory is that substances absorb especially the. r-rays. which would form their characteristic homogeneous radiation if they were used as ant ical hodes. The characteristic x-rays from iron are highly penetrating to alumi- num, and if these are especially absorbed the average penetration to aluminum is reduced. An aluminum screen iiist' increases the pene- tration to an iron screen beyond. This does not mean that more x-ray u'et< through the iron screen 1 han if the aluminum screen were not t here also. It means that a greater percentage of ray- which reach the iron screen get through it. Other Ways of Photographing Without Light. Electrophotography. - An ordinary photographic [date wrapped in black paper is laid upon a small sh'vt of metal about the same si/e. The latter is connected with the negative pole of a small spark coi! - 1 iii ! 'li . The film -ide i- upper- most and a coin is laid on top of the envelope. Over the coin another sheet of metal is laid which is connected to the positive terminal. A single spark is passed across the spark-^ap. I'pon developing the plate 698 MEDICAL ELECTRICITY AND RONTGEN RAYS a perfect image of the coin will be obtained. Around the periphery of the coin a ring or bonier of minute sparks will be seen. Bi-ch'i'troijrnphx.A coin is placed between two dry plates with the same result, the best results being obtained when the plates are bare- in a dark room. MiiifiHtoyrnphn. The plate is wrapped in light proof paper with the coin on top, laid directly on the film side of the plate. A piece of card- board i- laid upon the pole terminals of a powerful horseshoe or electro- magnet ; the plate facing the magnet is laid upon it. The armature i.- then gently presented to the glass side of the plate and allowed to remain as attracted by the magnet for a few minutes five to ten. The plate is developed and the negative obtained will show a shadow of the coin. The result is due to magnetism, not to .r-ray. Tin rmnijrn jihs. The plate is placed in water for a very short time; the coin is then laid upon it and pressed somewhat. The coin is to have a different temperature, either hotter or colder than the film. Copper coins should be used, as silver will not give the effect. The developer is then poured into a tray with the coin .-till in position. The coin is then removed and the development is continued. After ten or sixteen min- ute.-' development or even half an hour, we find an image of the coin there. The experiment should be made in complete darkness. Even ruby light would vitiate the result. lonization. The .r-ray ionizes a gas through which it passes, and therefore causes insulated positively or negatively charged bodies to lose their electric charge. Air through which the .r-ray has passed remains ionized for some time, and if aspirated through a tube this ionized air will discharge an electrified body which has itself never been exposed to the .r-ray. A plug of cotton wool or several layers of very fine wire screen will remove the ionization from air passed through it. Tossing about a large object, whether electrified or not. in ionized air quickly deprives the air of this property. It is gradually lost under any circumst ances. A'-rays ionize di-eleclric liquids as well as gases. A pencil of homogeneous .r-rays from copper or silver passes through a window of aluminum into the interior ot a cylmdric condenser, which metal liive- out hardly any secondary rays under the influence of rays characteristic of copper or silver. \V. Hratnr ha- made certain observations upon the ; '-rays, or sec- ondary cathode particles excited by the impact of .r-rays upon solid substances, ;tnd has found that the ionization of the surrounding gas is no more than would be accounted for by these secondary cathode rays. He coii-ider.- it doubtful whether the .r-ray itself ionizes gases directly. ^imill inn* are -udi as are produced by the pas-age of the .r-ray or ot t he hecquerel ra v- 1 h rough t he air. They move t h rough a distance ot about 1 cm. /.' / /'/ iniiK, ( lisc< >vered by Langevili, are .">() t lines more num- eroii- m i he normal at mosphere. but t heir mobility i- about '2000 1 hues less. An electrically charged body with a solid non-conductor like paraffin, i- tran-parent to the .r-ray, interposed, loses it- charge when ex- 1 10 -i i i iii t hi ra v, 1 iiit t his doe- not take place if 1 here is a complete outer onnected with the earth. The discharging effect is ,- mixed air. iinot be concentrated by len-e-. An ./'-ray picture is t -hadow, hence the name xlciu4 illustrates the most simple form of .r-ray tube at the present 1 00 Mini' vi. i.i.i.' 'i !'i< ITY AND HO.NTCKN KAYS, time. T represents tin- target, r anticathode,' which may bo of an> shape, tun which \\ill almoH always he placed neai' the center ot the h ,'h. and at an anu.le of I." decrees to the iomr axis of the tube. .1 is t lie external connection of the aiiticathodo; 11 i.- tlie external connec- tion iif the al , cup or cathode. The aluminum cup and the taruvi are ciimm<>M in all ordinary ,r-ray tnhes. and are practically alwavs placed in the aho\'e-descrihed portions. The next most common type of tube i- shown by I-'iir. -1 ;>.">. As you will notice, the target and aluminum cup are in the same relative posi- tion- as in ! iu.. \:\\. There is. however, an additional connection O, having :i flat aluminum di-k in-ide of the main liulli. Sometimes it is a flat di-k as -hown. and au'ain. it i- -imply a suai^ht aluminum rod which may be -harp-pointed. In a recent (iroene and Bauer tube the accessory anode consists of a sheet-iron cylinder which is supposed to certain deleterious it causes a gas to be liberated from 1 he mica disks, and in this manner lowers the resistance of the tube. If a connection from the positive pole of the apparatus is made to the terminal I), it causes the fine metal wire which is wound around a small u'lass rod to c . Fiirure l:! ( .> illustrates another type of self-rejjulatinj! tube. Thi acts in the -ante manner as the one above described, excepting that it does not have any device for increasing the resistance of the tube. A u'reat manv tube- are bein^' put on the 702 MKDICAI. KI.KCTHICITY AM) KOVH.KN KAYS apparatus, ami the aluminum cup with tin- negative pole of your ap- paratus, you are certain to have it connected properly, and whatever NO8. NO 11 N04 /htciiin inche nves about the same ray as the ',-inch machine. A ">-inch parallel spark-nap ui the static machine, and an s-inch parallel spark-gap on the coil the same as t he :}-ii id i on the static. A t ube that has a parallel spark-gap of '. inche-. should have the adjlistor so i-t stops the spark from appearing bet ween the terminals of the (Ill MK1MCAL Kl.Kt TKHTIY AND KONTCKN HAYS mil. Wlicn a tulu' has a parallel spark-gap of le-s than \ inch on a static machine, then hy means of what is known as a wicx spark-yci]) or Uiilit-nijuhttor, a- -hown in Kin. 111. a very much I letter ray can he oh- tained from the tuhe hy separating o and -1, so that a spark appears he- tween them. If the tuhe is very low. having a parallel spark-gap ahout J, inch, then it mav he necessary to separate* > and 1 on each side from 1 to 2 inches. AYhen this is the case, a multiple -park-gap, as shown in Fir. 11."). gives a more steady ray. This is due to the fact that the row of hrass halls keeps the spark in line, and it doe- not tend to fly oft. as when a single spark-gap of the same total length and resistance is used. The action of the series spark-gap in conned ion with the static machine is to allow it to generate more current. A static machine on ry low resi-tance. -uch as i- the e;ise when all parallel .-park-nap of 1 indi i- used, \\ill genera te a amount ot current, whereas, when a resistance e rurcmt. it uenerate- more current, and, in fact. : rod need in the curciiit , the more current the ma- 1 i" i'- capacity. A-ide iVom the -hurt parallel il-aiion that a tulie is lo\v or -oft i- the appear- THE .f-UAY anco of a blue stream hot ween the target and the aluminum cup (Fig. 441)- The majority of the .r-rays are generated on the target at the point at which this blue stream strikes, and this blue stream is called the cathode stream. Prof. S. P. Thompson has demonstrated the fact, that the .r-rays are given off in equal numbers in all directions from the anterior surface of the target , and not a maximum number at right angles to the (-(Miter of the target. Caution: When a tube is to be used do not separate 1 the secondary terminals of the apparatus more than 1 inch beyond the parallel spark-gap of the tube; and if it is used on a static machine, and has a parallel spark-gap of more than '*> inches, then use the regulator just sufficiently to obtain a 3-inch parallel spark-gap, and if on a coil, an S- or 9-inch parallel spark-gap at the most. The .shorter the parallel spark, the less will be the penetrating quality of the rays. When a tube of the type shown in Fig. 444 is connected as follows: C to the positive terminal, H to the negative terminal, then if this is a incdinni tube, those connections will give the least parallel spark- gap of this particular tube. If the positive connection is made on the terminal .1. the parallel spark-gap of the tube will be Non/ctrltat higher, and if (' and .1 are connected and then connected to the positive ter- minal, this will give the lii inches, and under no circumstance be brought nearer than 1 inch to the terminal B. for treatment purposes the exposure is usualh much shorter than when the usual tube is used, owing to the small diameter of the bulb, and consequently, the part treated being closer to the target. When used on an .r-ray coil, the connections and applications above described apply, with the exception that the terminals on the coil can be separated 1 or "> inches, never more than that. The current to excite this tube should not be very strong If an electrolytic inter- rupter is used,, a current of 4 or "> amperes is all sufficient; if a mercury jet interrupter is used, a current of '2 amperes will be sufficient. The point to be specially careful about is bringing the pointer too close to the negative terminal, as if this is done it is possible to release so much gas that it will be necessary to have the tube re-exhausted. This, however, cannot occur if the pointer is at least 1 inch away from B, and. if the current *ti'< no apparently shortens the life of the .r-ray tube itself. This bad feature, however, can now be eliminated by means of the Yillard valve. This has been improved on and made self-regulating. Figure 4-lf) illustrates an .r-ray tube having considerable inverse cur- rent. This is shown in the first place by the green ring, and in the second by a more intense green at 11 . \\hile this tube would light up a tluoroscope very well, yet for taking a picture it would not be a very 708 MKDICAL KI.KCTKIC1TY AND H()NT(iKN KAYS good tube, owing to the fact of the cathode stream from the 1 inverse current striking the glass at 11" and causing wild .r-rays to he generated B B IP A Fi<_ r . 440. Osrillosropp with utiidin-ctional current. THK .r-KAY 709 at this point. Those rays interfere with the clearness of the picture. Inverse current is most pronounced with very high-resistance tubes when excited by an x-ray coil. This, however, is done away with by (lie use of the improved Yillard valve (Fig. 4-17). The inverse cur- rent can also bo demonstrated by a little instrument known as the oscilloscope (Fiji. 44S). When placed in circuit with a source of high- tension current, if the current is one direction only, then it shows a broad violet band on the end which is negative (Fig. 449). If connected with an oscillating current of high tension, it shows a violet band of equal width on both sides (Fig. 4oO). If connected with an alternating current of high tension, but the alternations being stronger one way than the other, then it shows a broad band on one end and a smaller band on the other end, as in Fig. 4">1. This device is especially useful in connection with the Yillard valve, as it will show whether the valve is in good working order and cutting off all of the inverse current, in which case the oscilloscope will have the appearance as shown in Fig. i ID. When a tube has boon punctured or broken, so as to admit a con- siderable amount of air at atmospheric pressure, this fact is indicated by a spark passing from the aluminum cup to the target. If, however, the regulating device has been used with too strong a current or for too long a time, then the tube shows a violet color throughout the entire bulb, and this is also the appearance when a tube has become a leaker. In both these conditions the only thing to do is to send the tube to the maker and have it re-exhausted. If it is an expensive tube it will very likely give better satisfaction if you send the electrodes to the maker and have a new tube made, using the old electrodes. Figure 452 illustrates the way to connect an .r-ray lube in circuit with an oscilloscope and a ventril tube. Care of the Fluoroscope. A fluoroseopo (Fig. 4oo) requires, in the first place, to be kept in a moderately cool place. It should also Fiji. 4~>3. Oryptosropc <>r l>ox fluoroscopp. have a cover made to go over the eye-piece 1 , so that when not in use no dust or dirt can fall on the screen, as the screen is made 1 of one of the most sensitive salts and a very little dust will cause it to decom- pose, thus losing its fluorescent property. A -hoot of lead glass over the screen protects this and also the observer's eyes. After a varying ,Vni:th <>f time the screen begins to deteriorate at the edge. This tlctrriordlinn is indicated by a change of folnr. \\hen the screen is new and in Li'ood condition it will have an apple-green color; as it begins to de- / 1U MEDICAL ELECTRICITY AND HONTCKN RAYS teriorate. the edge will begin to turn color, and this will extend finally over the entire screen, it being an orange brown. This change is gradual, and as it occurs the fluorescence of the screen diminishes; however, it does not cease entirely, so that it frequently happens that a physician finds that he is not able to see as well with the fluoroscope as formerly . and he will imagine that there is something the matter with the tube or the machine. He most often concludes that the trouble is with the tube, and will order a new tube, but he fails to get a better result . owing to the fact that the trouble lies with the screen and not with the apparatus. A hand-guard of zinc protects the operator's hand. An operating fluoroscope is made with the enclosed box fastened over the operator's eyes, but with the fluorescent screen hinged so that it can be turned back. Part of the time the operator is looking at the x-ray image and part of the time directly at the field of operation. It may be provided with an orthodiascopic feature. Fluoroscopy. In the first place, remember that the .r-rays are inii*ihl<- and that the green fluorescence of the tube is due to the cathode- Fit', l.Vt, Tin John-ton finoro.-cope. The operator stands at one side instead of in n rays and r-rays which strike against the glass, causing it to fluoresce^ A tube made of lead glass instead of fluorescing yrcni, fluoresces blue. 'I'h'- platinobarium cyanid crystals when struck by the .r-ray fluoresce, ::: ; it is 'hi- effect that we see ;inm its front surface 1 proceeded in perfectly straight line^ and therefore met at its cen- ter of curvature 1 . The 1 impact of the 1 cathode 1 stream produces mo- tion. and will turn a pimvhcel plae-ed inside 1 the 1 vacuum tube. It pro- eluces sufHe-ient heat te> melt the 1 platinum or even the 1 tungsten elisk in an .r-ray tube. It produce's fluorescene-e of the glass wall of the tube and of many other substances; some of the phosphorescent colors produced are 1 : with sulphate of copper, a faint green; with >ulphate' of coppeT containing a trace of sulphate of manganese 1 , a bright gree-n: none 1 with sulphate of strontium; with sulphate of strontium containing a trace of sulphate of manganese, a bright red: with barium sulphate, a faint dark violet; with barium sulphate containing a trace of sulphate of manganese, a dark blue-: with magnesium sulphate, a red; with magnesium sul- phate and a trace 1 of sulphate of manganer-e. an intense dark red: with sulphate- of zinc, a bluish color; with sodium sulphate 1 containing A of 1 per ce'iit. of sulphate of manganese, an intense- brownish yellow; with cadmium sulphate', a yellenv: with iluorid of cak'ium. a faint blue; with Huoriel of calcium with a trace' of hydrid of manganese 1 , an intense blue. The most striking effects, as may be seen above 1 , are on "solid solutions." These are termed bv two salts, one iiivatlv in exce'ss of the , 12 MKDICAL KLI-XTKK'ITY AM). HONTCKN KAYS other, precipitated simultaneously from a watery solution. The cathode rays produce upon the glass wall of the tube shadows of any -olid body which may intercept their path through the vacuum. They render any gas through which they pass a conductor of electricity. They carry a charge of negative electricity and any solid substance which they strike gives out generally diffused, not alone perpendicular, cathode ray.-, and also .r-rays. Cathode rays do not emerge from a glass vacuum tube in any appreciable amount unless a thin sheet of aluminum is hermetically sealed into an opening in the glass. The aluminum is tran-parent to these rays and acts as a sort of window if placed at the spot where the cathode rays impinge. Iler/'s discovery that the cathode rays, as he thought them to be, would penetrate gold-leaf, was made by covering a small piece of ura- nium irlass with gold-leaf, leaving an uncovered edge of glass exposed all round. Bringing this piece of glass near the tube and opposite the cathode pole, he found that the piece of glass which was uncovered became fluorescent and that it increased the vacuum still more within the tube, even the glass back of the gold-leaf was rendered fluorescent. This apparently was an effect of the x-ray, but at that time (1892) it was not recognized as such. Lenard, a couple of years later, in his experiments with the rays that go by his name, found that phosphores- cence was sometimes caused even beyond substances like aluminum. If the aluminum is .00265 millimeter thick the rays pass through in sufficient amount to cause visible light and produce phosphorescence. The most phosphorescent substance, according to Prof. ,1. ,L Thomson (now Sir Joseph Thomson), whose book on the "Transmission of Electric- ity through Oases" is a recognized source of information, is tissue-paper soaked in pentadekylparatoleketon. These cathode rays outside the tube are called Lenard rays. They spread out very diffusely and pro- duce shadows larger than should occur geometrically. They cause photographic effects, are arrested by quart/, but alum is transparent to them. But some of these effects may be due to the presence of the .r-ray. Lenard rays discharge negatively or positively charged bodies, a- do t he x-rays. Cathode rays may be shown in an ordinary electric-light bulb by connecting one wire with a piece ot tin-foil pasted on the outside of the bulb at a distance from the metal part of the bulb. The latter is con- nected with the other electric-light wire. This experiment and the other, of making the same connections between the bull) and the wires from an .r-ray coil, u'enerally resul' in burning out the incandescent filament and spoiling the lamp. The vacuum in electric-light bulbs is too 1< iw ti i . who found that with a perforated cathode < Fig. }.">.">) certain ra\> occurred behind the cathode which did not seem to be deflected !;\ a maunet, and whose only known proper 1 v i- that ot bemti accom- panied li\- lumino-itv. Thomson'.- explanation ot these is that they are lets of phosphorescent u'as produced bv a sort ot explosion at the cathode. le cent experiments bv \\ ien and bv .1. .1. Thomson' have shown that the kanal-t rahlen of (ioldstein are charged with po-itive electricity. ire deviated b\ a mau'tieti' 1 field or bv an electrostatic field in the oppo-ite direction from that followed by the cathode rays. But the TIIF. .r-HAY 713 magnetic field must be very much more powerful and the means of observation much more exact than in the latter case. Channel rays may be studied by having an enlargement of the tube back of the cathode, containing a fluorescent screen. They carry a positive charge of electricity, and their deflection by a magnetic field is evidenced by the displacement of the fluorescent spot on the screen. ClKinncl ra//.s ionixe gases through which they pass. lonization by Cathode and by Channel Rays. 1 - The cathode rays in passing through an atom repel or attract the corpuscles which are eon- Kanalstrahlen or channel ray?. tained therein and communicate kinetic energy or motion to them. If this energy reaches a certain value, a corpuscle escapes from the mole- cule in such a way that there is a production of a free corpuscle and of a positively charged atom. A Wehnelt cathode is one covered with lime and heated and has a hole in it. It affords channel rays in abundance, and is suited to the production of very soft .r-rays with a current of 1000 volts or less. Positively Charged Particles in a Vacuum Tube. As intimated in the last paragraph, it seems moderately certain at the present writing that there are such things as positively charged particles in motion inside a (leissler tube which has a vacuum of about y^o atmosphere If this be really so, it does not necessarily interfere with our conception of the cathode stream, but it may to a certain extent cause us to revise our idea that the latter is practically the sole factor in the transmission of electricity through gases and that the current i> unidirectional, from t he cathode to the anode. The energy of the .r-rays is ^ that of the cathode rays which produce i hem ' M. Wien) . The energy of the x-ray is proportional to the energy of the cathode ray- producing it. The energy of a cathode particle is proportional to the fourth power of its velocity. Conversion of ./-Rays into Heat.- The absorption of the .r-ray in passing through a sheet of metal causes a certain amount of energy to be converted into heat. Adams- has measured this amount of heat by very delicate apparatus. 714 MF.IMCAI. KLKCTUICITV AND RONTdKN HAYS Sonic of liis results agree with observations made upon the x-ray by other workers with different methods. These are: the percentage of .r-ray absorbed is independent of the intensity of the radiation; there is very little surface effect like that which reflects or disperses or absorbs ordinary light : a smaller proportion of the .r-ray is absorbed, by a second similar metallic sheet than by the first one; but this dot's not hold good in the case of .r-rays passing first through aluminum and then through silver; they are less penetrating for silver than nor- mally. An observation made by Adams' thermometrie method which differs from that supposed to be shown by other methods is that the amount and quality of radiance which passes through two sheets of different metals is the same no matter in what order the}' are placed. Accord- ing to this observation the ./--ray undergoes no change in quality in pass- ing through different metals. The original radiation consisting of rays of less penetrating power and rays of more penetrating power encounter a sheet of metal which .-lops a greater proportion usually of the less penetrating rays. The rays which pass to the second metallic sheet penetrate this in greater proportion, not because they are rays which have been rendered more penetrating by passage through the first metal, but because they are the original more penetrating rays from which the less penetrating ray? have been separated by the first sheet of metal. Assuming his observation about the different metals to be correct, we ;/ a Static Mar/, int. The same .r-ray tube which will back up a spark of about ") inches with an induction-coil will back up one of only about 1 inch with a static machine. The author regards this as attributable to the greater loss of high-tension static electricity by a brush discharge from the terminals of the tube and from metallic points about the ords. 'arunt/i aj an x-Raij Tnhc far [ *< irit/i a Static Machine. a static machine the tub' 1 employed should be one manufacturer in good condition for use with this oubtless remain in perfect condition for a very long discharge does not usuallv heal up the tube and so Miles of gas. A lube for Use 1 of use. If the 1 ube i d be used very rarely indeed Lowering the vacuum a very little too much Use with the static machine, because the current iii^h to scatter panicles of metal through the excess of gas. It' there is one of the spark regu- found necessary to connect the negative wire im reducer and no] depend upon leaving the :d attached to the cathode and turning the Iven with a direct connection it mav be found York Mc. I'M).-,. TIIK .r-RAY 717 that the amperage of the current is insufficient to liberate the necessary amount of gas. If one lias an induction-coil as well as a static machine, it is an extremely easy mutter to regulate the vacuum in the tube by the use of the induction-coil and then to use the static machine to run the lube. This might be done for some treatment or experiment where a lonu, mild, uniform exposure was desired. If LCI/I lot /V//'.s are used to act uute an .r-ray t ube with a static machine they should not be larger than pint bottles. The internal armatures un- connected with the prime conductors and the external armatures with the poles of t he .r-ray tube. The voltage from a xtatir ui/ir/i/'/n is very high and is measured by tin- distance across which a spark will pass between the two poles or by an electrostatic voltmeter or, indirectly, by an electrometer. The latter is a refinement of the simple electroscope, in which the two gold leaves separate when they both become charged with the same kind of elec- tricity bv bringing a changed body near the rod from which they are suspended. The electrometer shows the density of the electric charge at any part of the apparatus or of the patient, and this varies with the voltage of the source of electricity and is also greatest upon the surface and (-specially upon sharp projections from the surface. The voltage produced by a good static machine is 100. 000 or more. The amperage is very small indeed, but is still demonstrable by means of a milliam- peremeter of the movable wire coil variety (d'Arsonvul milliumpere- meter) or by a pole detector in which the electrolytic effect of the current produces a red color in the' liquid. The physical and physiologic effects of the static discharge are due almost entirely to its tension or voltage and scarcely at all to its intensity or current strength or am- perage. It has polarity, however, and the proper direction of the cur- rent is necessary for the excitation of an .r-ray tube. An Induction-coil Operated by a Galvanic Battery. The battery should be the equivalent of 30 to (>0 Leclanchi'- cells (8 to 16 cells will do) connected in series, and the current from this should pass through the primary coil of thick copper wire surrounding a core of soft-iron rods. The primary coil is slipped inside the secondary coil, to which it is not connected in anv way. The secondary coil consists of thousands of turns of very fine copper wire carefully insulated and terminating in two poles from which the conducting cords are to lead to t'he .r-ray tube. Each time that the current begins to flow through the primary coil a wave of electricity is induced in the secondary coil, and again when the current is turned off. The break-current induced in the secondary coil is stronger and in an opposite direction from the make-current. The primary current is turned on and off very rapidly by a vibrator. \\hen the current is turned on, the primary current causes the soft- iron core to become a temporary mairnet and this attracts the iron armature, whose motion toward the core btvak< the contact and the current ceases. The iron core ceases to be a magnet and the arm-Mure, which is upon a spring, returns to its original position and the contact is airam made. Such a coil requires a condenser of many sheets of lead toil separated by sheets of mica or paper to take up the extra currents occurring in the primary coil. The value ot a condenser for an induction-coil used to excite an .r-ray t ube except wit h an electrolytic interrupter is easily demonstrated. The interrupter works more steadily and the fluoroscopic and radio- 71S MKD1CAL KLKCTUK 1TY AM) RONTGEN HAYS uraphic results arc much l>cttcr. r rrcatincii1s and the lighter forms of fluoroscopic and radiographic work may he very \vcll done with such a coil. Kiirure -I")!) \vas made with a coil and galvanic hattery in 1800 hy Dr. T. W. Kilmer, then one of my assistants at St. Bartholomew's clinic. An Induction-coil and Storage-battery.- The 100- volt storage- hattery of an electric aiitomohile will operate any kind ot a coil and interrupter. The storage-hat tery itself need no! he carried into the room in which the coil is placed. It is only necessary to run a douhle, heavily insulated wire from the charging plug of the aiitomohile to the ./-ra\ apparatus. The .-mailer portahlc storage-batteries in which each ' 1! \veitih.~ about 10 pound.- operate an s-inch 1 coil with a mechanic interrupter very u<-ll. About six sucli cells are re, that when a current of electricity is passed through a liquid and one of the metallic electrodes is very small t he surface of t his elect rode becomes covered with a laver of heated gas or vapor which interrupt s the flow of the current . The current stop- ping, the gas. or vapor is dissipated and the current begins to flow again with the same re.-ult . These depend upon the thermal effect of an electric current when it passes through a liquid path with a very small cross-section. The current will not cause excessive heating if it passes from one large metal plate to another submerged in a liquid which is a good conductor of electricity. But when all the current has to pass through the small amount of liquid represented by a pin-hole in a porcelain jar or by the fluid in contact with a small platinum point, the resistance of a 1'ric- tional character becomes so great that the liquid not only boils, but is converted into a mass of incandescent gas. This effectually destroys the electric contact between the liquid and the platinum point in one type of interrupter; or between the two bodies of liquid in the other type. In either case the good conducting path afforded by the dilute acid liquid is broken by the introduction of a mass of gas which arrests the whole or a very large 1 part of the current. Xo sooner has the current ceased to How than the incandescent gas disappears. It partly collapses under the pressure of the liquid or rises to the surface in bubbles. The flow of the current is no longer obstructed, but its reestablishment is attended by the formation of a fresh mass of incandescent vapor and a new arrest of the current. In this way interruptions are produced at regular intervals and of a character extremely well suited to .r-ray and high-frequency currents. The smaller the surface of platinum exposed in the Wehnelt and the smaller the holes in the Caldwell-Sinion inter- rupter 1 the more rapid the interruptions and the weaker the primary current, and. generally speaking, the weaker the .r-ray or high-frequency current excited by the secondary current. Electrolysis takes place in either of these interrupters with the liberation of hydrogen gas at t he negative and oxygen gas at the positive electrode, and there is some liability to an explosion if the two gases are allowed to minule in a confined space and then become ignited by a at some loose electric contact. The result is more disagreeable erous. the cover of the box being thrown a few inches into the dilute acid being spattered over neighboring objects. There i- of absolutely preventing such an explosion, but ifs occur- de very unlikely by certain precautions. The inter- not be tighllv closed. If it is covered at all. there pie opening for the escape of hot sulphurous fumes cm-rent. This results in a general diffusion of the pin 'ii in the air of the room instead of their being filtrated and explosive form in a small space. The ins fume- thus allowed to escape from the interrupter [well. 'in \!neric:i, mid Simon, in Kun>|>e, invented (hi- tvpe of interrupter V- in i '!::: j 'hr.iLTin bet \\ ceil t he t \vo h:dve- i if , ;\ vessel coll t M i I] i Iltr the elec- ! nd I Idwell ;ils(i figure in their excellent book :in interrupter in / 'I i he communication is r<' or 30 amperes under varying conditions. The electrolyte is sulphuric acid 1 part to (i parts of water. A substitute may be 1 part \valer and 1 part saturated solution of Hochelle salt in water, a small amount of sulphuric acid having been added. The Rochelle salt alone in the electrolyte does away with the disagreeable fumes, but its solution is not nearly as good a conduct or of electricity as dilute sulphuric acid, and consequently the current is weakened and much more heating of the liquid occurs; and it becomes quite a task to fre- quently (i pen the jar and pour in water to make up for the rapid evapora- tion. The plat inum in each is a cylindric rod about f mm. in thickness, and a greater or less length is protruded from its porcelain sheath by turning an insulated knob at the top of the hard-rubber tube in which it is held. \\ith the Caldwell-Simon interniptei the polarity of the current makes no difference; but with the \Yehnelt interrupter it is essential that tlu> positive battery wire should lead to the platinum point: and if tin wrong connect ion is made. 1 he interrupt ions are irregular and the sound is rough and deep and the platinum i.- much more rapidly worn away. 4ti 722 MEDICAL ELECTKICITY AND RONTGEN RAYS The cause of this is probablv the formation of a sheath of hydrogen gas upon the surface of the platinum when it is connected with the negative wire, and this sheath presents great resistance to the electric current. This hydrogen sheath forms a barrier even when a large portion of the platinum is exposed, and it produces more continuous resistance than the intermittent disconnection which is desired. This electrolytic- effect is separate from and additional to the thermal effect due to the Miiallness of the liquid conducting path at that point and the conse- quent ohmic resistance or friction. The Wehnelt interrupter is the only one which may be directly connected with and will partly rectify an alternating current. It works fairly well. but. of course, the platinum point has an undesirable polarity half of the time and wears out much sooner than it would if it were connected with the positive wire all the time. All the other types of interrupter for induction-coils require that alternating currents shall be rectified or made unidirectional in order that they can be used, and it is better to do so even with the Wehnelt The different means of rectifying the current will be described in another part of this book. The \YcJnuil int< rntptcr (Fig. 458) is exactly on this principle, the fluid being sulphuric acid diluted with six 1 hues as much water, the large electrode is of lead and the small one is of platinum wire enclosed in very tough porcelain. By means of a screw ad- justment a larger or smaller amount of the platinum may be caused to project beyond the porcelain and the electric impulses made small and rapid if little of the platinum is exposed; and heavier and less rapid if a greater length is exposed. The platinum should always be connected with the positive wire. Such an interrupter works well with the direct 110-volt current and over a range of from 5 to '.*>() or even 10 amperes. It does not work after the fluid becomes overheated, so it iq necessary to have 1 wo or more if the apparatus is used continuously. C 1 fil//n(l/ or Simon Interrupter. The other type of electrolytic inter- rupter is exemplified hy the Caldwell or Simon interrupter, in which then' are t wo large lead elect rodes dipping into dilute sulphuric acid, the vessel containing which is divided by a vertical partition. The current through pin-holes in this partition and the liquid conductor at narrow plate.-, of course, presents great resistance, the liquid is i. and a mass of vapor cuts off the current. e most practical interrupter of this type is a beaker interrupter lor me I iy Wappler. under Caldwell's [latent, and first published Ye in tny article of October L' I. IDO.'i (Medical llecord). "This - of a large porcelain jar, partly filled with dilute sulphuric acid i''h i- set a -mailer jar with a pin-hole (three holes are better) near the bottom. One conducting wire terminates in a leaden i!itcrrii]>t(T .'{'. inch THE X-RAY 723 ring resting in the acid in the outer jar. The current passes through the liquid and the punctured jar to the leaden plate resting in the acid in the inner jar, from which it passes by a conducting wire to the rheostat, and then through the primary coil and thence back through the 1 negative wire to the wall socket." The Wehnclt interrupter works with an alternating current, but not so well, and with more rapid wear of the platinum than with the direct current. The platinum really ought to be the positive pole, and with an alternating current, of course, it is the negative pole half the time. For .r-ray work with an interrupter of the Caldwell type the alternating current must usually first be changed to a direct current. This can be done by means of a motor generator, which is really a dynamo run by an electric motor, or of a mercury arc rectifier, in which the current passes through mercury vapor which permits the passage of the currents in only one direction, the alternate currents being suppressed. Either of these means is effective' and would be chosen for an office outfit, but for an outfit at a patient's home the simple and inexpensive aluminum cell in which the fluid is a per cent, solution of Rochelle salt or of sodium bicarbonate, and one electrode is of lead and the other of aluminum or carbon, suppresses the alternate current perfectly well for treatment and for all but the heaviest and most rapid radiography. Aluminum Cell Electrolytic Rectifier. It transmits about !)() per cent, of the currents passing in one direction and very little of the currents in the other direction. The jar should be capable of standing a certain amount of heat. This enables one to use the YVehnelt interrupter with- out undue consumption of the platinum point; and either the Wehnelt or tin' Caldwell interrupter with good functional results in the illumina- tion of an .r-ray tube. It has been described in the preceding para- graph. Crookes's Jilm is a layer -i^Vo m( ' n thick which forms upon the lead surface in the electrolytic rectifier and acts as an enormous resistance 1 to the flow of current in the wrong direction. The current can only flow freely when the lead electrode is con- nected with the positive pole of the source of electricity. The 1 lead in the electrolytic rectifier should, therefore, be connected with the lead in the Wehnelt interrupter. (Vr/xxo/r.s- rectifier is an aluminum cell in which the other electrode is of iron or some other indifferent metal. When the aluminum is positive it is covered by bubbles of oxygen and a layer of aluminum hydrate, which greatly impedes the flow of the current. HY//m//'.x Rectifier for Alternating Current*. This is a vacuum tube in which the cathode is made of platinum, gas-carbon, or tantalum, and c-onsequently does not melt when heated to incandescence. The cathode is coated with a metallic oxid. The rarefied gas offers very little resistance to the passage of a current in one direction, but if the current is reversed, so as to make the elect rode coated with oxid the anode instead of the cathode, the current is almost completely arrested. The effect is supposed to be due to ionizution of the rarefied gas in the tube by the incandescent metallic oxid. The Mercury Dip Interrupter (Fig. 4f>9). One of the wires carrying the primary current leads into the bottom of a glass vessel containing a certain amount of liquid metallic mercury. The other wire is connected with a vertical metal rod which is moved up and down by a small elec- tric motor and ulternutelv dips into and is withdrawn from contact 724 MEDICAL ELECTRICITY AND RONTGEN RAYS with the mercury. The contact is thus made and broken and the alcohol which covers the surface of the mercury prevents the formation of an arc. The interruptions are of u'ood character and may be regulated as to rapidity by varying the speed of the motor. The Mercury Jet Interrupter (I'i. 460). One of the primary win ti-rmmates in the liquid mercurv. the other in a sonos of metallic sec- tions separated by insulated spaces which form a horizontal bolt lining if the alcohol reservoir a certain distance above the sur- A M elect ric mot ( ir causes the rr'volul ion of a vert i- into the metallic mercury. V>v centrifugal force dt ' iti into a i u be m tin- .-halt and 1 hr< >\vn out 1 hrouidi THE .C-RAY 725 11 horizontal nozzle. The jet of mercury pusses through tlic alcohol to conic in contact with one of the metal segments and complete the; metallic circuit. At the next part of the revolution the mercury jet is ;lirecte 0-volt direct current and the speed of which can be regulated by means jf a rheostat. A leather belt con- nects this motor with the vertical axis of the interrupter and causes it to revolve. Two conducting wires, one from the wall-socket of the 110- or 220-volt electric-light cir- cuit and the other leading to one ter- , ,. . . '' . . . ]!" 4(;i.Ropiqupts mercury turbine minalot the primary of an induct ion- mti-rrupter. coil, are fastened to vertical metal rods which can be raised or lowered "by insulated screws. These ] of but do not reach the level of the s pounds of mercury in the bottom of the interrupter. At their lower extremity these rods expand into triangular -nirfaces, large above and pointed below. The lower part of the revolving axis is hollow and contains a pump, on the principle of the turbine or a sort of cork- screw motion, which draws the mercury up through the hollow shaft of the vertical axis and out through two horizontal tubes. These two tubes also revolve with the vertical axis and centrifugal force is added to that produced by the pump. Two jets of mercury are thrown out through the alcohol in a horizontal direction and as the axis revolves ihe>e jets also make complete revolutions. In a certain position the two jets impinge upon the two metal electrodes and form a complete conducting path of metallic mercury between the two electrodes. As the jets continue to revolve, they pass the point at which they are in contact with the metal electrodes and the circuit is thereby broken, but besides this they strike against hard-rubber or other insulating barriers. These are placed obliquely and as the mercury strikes one of them it, of course, is prevented from going out as far as the metal electrode. The breaking of the electric contact is rendered much more complete and sudden than when the sole dependence is placed upon the circular sweep of the mercurv jet. lu the latter case the break spark is of considerable volume because the mercury docs not get far enough away from the metal electrode for quite an appreciable length of time and there is also a perfectly straight path between them. "\Yith this new improvement the mercury jet is instantly stopped at a considerable distance from the metallic electrode and the formation of an arc is 1 L'uolishc.'d March 10, I'lni.i, Archive- dVh'Ctricite Mrdirale, Bordeaux, l-'ranc-j. 726 MEDICAL ELECTRICITY AND RONTGEN RAYS further prevented by the oblique direction of the hard-rubber barrier, As the mercury jet passes over this surface the break spark would have to turn quite an acute angle in order to pass from the electrode to the mercury. The rupture is so complete that no condenser is required to suppress the break spark for safety to the apparatus or for securing a good quality of induced secondary current. This interrupter also enables one to dispense with a rheostat or a volt controller, because the strength of the current can be regulated from 1 to 1"> amperes by ad- justment of the interrupter alone. The way in which the current strength is increased is by lowering the metal electrodes and thus pre- senting a wider surface for the mercury jet to sweep across and increasing the fraction of each revolution, during which the current flows. The average strength of the current is what is meant when we say that a primary current of a certain number of amperes is used. This is de- termined by the proportion between the time that the current is flowing and the time that it is interrupted. There is a very small total resist- ance in the circuit, 1 or 2 ohms resistance from friction in the primary wire and not much more additional resistance from self-induction and practically no resistance in passing through the conducting jet of mer- cury in the interrupter. At any time that the current is flowing it may encounter a total resistance of only 2, o, or 4 ohms, and, according to Ohm's law. the current strength would be from 50 to 20 amperes with 100 volts or 100 to 40 amperes with 200 volts. The strength of the current in amperes is equal to the number of volts divided by the resistance. Such a strength may actually flow for fractional periods of time during the passage of the current through this interrupter, but the periods of time during which there 1 is no current at all brings the average down to a much smaller number of amperes. This is regulated at somewhere between 1 and 15 amperes for most therapeutic purposes. There is no possibility of the interrupter stopping in such a position as to produce a stationary mercury bridge across the space between the metallic electrodes and permit a continuous flow of the current which, of course, would be destructive because of its strength. The mercury bridge is only formed when the axis is in rapid rotation; when the shaft is stationary there is no turbine pump force at work to raise the mercury in the hollow axis and no centrifugal force to impel it out horizontally and cause it to strike against the two electrodes. The amperemeter which measures the strength of the primary current indicates the average number of amperes. Kven if the instrument were made with a needle which would pass back and forth from the zero to the .">() or ]()() ampere mark on the dial scores ot times a second it would be useless. The eye could not follow its motions, and even if it could we should not obtain the information that we require. \n obturator may be adjusted to prevent the two opposite mercury jets from strikinij.- the metal electrodes in one position while they still continue to do so when in the opposite position. This permits of the passage ot the current onlv once for each complete revolution of the a\is instead of twice, as is the case when the obturator is not used. I.;i''!i tiny traction of a second that the current (lows produces practi- the same effect upon an .r-ray tube, whether this occurs once or twice for each revolution of the axis. The visible effect and the Huoro-cn ill I,,' about the same in both cases. The obturator and the : ite of current How may be used for fluoroscopic ex- THE X-RAY 727 animations and will avoid wear and tear upon the x-ray tube and reduce by one-half the effect upon the patient. It will be found best to dispense with the obturator and thus secure the double rate of current How for making radiographs, the same quantity of radiation being produced in half the time. Kither the single or the double rate may be used for x-ray treatments, due allowance being made for the difference in the amount of radiance. This may be made clearer by an example in ordinary photography. If we have a 100-candle-power arc light which is only turned on for one-sixth of every small fraction of a second, it will illuminate the interior of the room to the full 1000-candle- power extent each time, and the persistence of the effect upon the retina of the eye may enable one to see objects practically the same as if there were two such periods of illumination for one-sixth of the time or a total of one-third of each small fraction of a second. The effect regis- tered upon a photographic plate or its physiologic effect upon plants or animals would be twice as great with the double as with the single rate of exposure. Somewhat similar variations in the current may be obtained with the \Vehnelt interrupter by having different sixes of platinum rods and means for regulating the length of the platinum rod exposed; by using a variety of electrolytes of greater or less conductivity and by the use of a rheostat. Ropiquet's interrupter supplies the desiderata of a mathematic regu- lation of the average strength of the current ; a uniform strength of current while the contact is made and a very sharp and perfect break; the regula- tion of the number of contacts per second and of the relation in time between the duration of each contact and the interval between them. Kither a rheostat or a volt controller may be used with this inter- rupter and will supply useful though not essential modifications of the current. It will enable us, for instance, to modify the strength of the current without changing the duration of each contact, as is done when the strength is regulated by adjustment of the electrodes in the inter- rupter itself. Care of Mcrcnnj Interrupters. There is a small amount of sparking as the contact is broken in all these mechanic interrupters, and this corrodes the metal surfaces and the alcohol becomes muddy and has to be changed. A scum which forms upon the surface of t he mercury must be washed off occasionally, so that a certain amount of expert care is required at short intervals. Fortunately, the motor is not likely to get out of order frequently. The alcohol does not often take fire from the sparks at t he making and breaking of the contacts because the latter are below the surface and no free oxygen is present to combine with the alcohol. But when this does happen there is danger of fire. These mechanic interrupters are excellent for x-ray and other extremely heavv elect rot herapeut ic work, but they are more expensive and more; com- plicated than electrolytic interrupters. 77/r ( 'oiri in iitittnr T/ip< of I ntrrrii ptcr. One of the best of these is the Johnston interrupter, made by the \Vestinghouse Company. It is an electric motor whose shaft dips obliquely below the surface of alcohol in a metallic reservoir, and upon this shaft is mounted a series ot metal contacts alternating with insulated spaces of mica or indurated fiber. As this revolves, a stationary metal brush comes in contact first with a metal section, making the current, and then with an insulating <2N MKIMCAL KLKCTHICITY AND RONTGEN KAYS section breaking the current. Submersion below the sui'face of the alcohol prevents the format ion of an arc as the current is broken. The Conlrcniulin itihrrnphr (Fig. 402), made by (laitfo, of Paris, i< another of the commutator typo. A small electric motor causes the revolution of a disk of insulating material in which are inlaid strips of metal as in Fig. 402. Four strips of metal separated by portions of the insulating substance form the rim of the disk and separate metal strips connect the opposite strips; so that there are two independent pairs of metallic conductors separated by non-conducting sections. The cur- rent passes through metallic brushes which are at opposite sides of the revolving di-k and press upon its periphery. At times the brushes are pres.-im: airamst the surfaces of one pair of metal strips and. of course, the current i> transmitted. At other times the brushes are in contact with i he insulating material and then the current ceases to flow. Then the disk revolving to another position brings the other pair of metal .-trips in contact with the brushes, completes the electric connection. and allows the current to How again. The number of interruptions per second is varied according to the speed of the motor, and then again the apparatus may be made with more than two pairs of conducting strips. and this will increase the number of interruptions produced by each revolution. This is a really excellent type of interrupter for currents of p anv moderate strength. Its action i- positive each make and break beinir perfect without any ineffectual contacts, as with a vibrating interrupter, but arcing i- liable to occur \\i;h the heaviest r-ray currents and it should be submerged in alcohol if U-cd for that ] nil') >ose. ( '/iri'< nfii r's * nil rr n jilt r i Fig. 40)-$) is of the atonic or < r/txlir tvpe. The hammer \\lnch is to be attracted bv the magnetized mm core of the primary coil i- upon a ri^id stem which is drawn away from the core 11-1 the point of a screw bv the traction o| a spiral spring. 1 :: no p. >-ii in 1 1 doe- i he ha in n HT or its -lei M t ran -mil the current. \\ hen the current i- turned on the mm core becomes an electromagnet and at t ra''t s the hammer, v. Inch, moving forward, presses against a straight spring v.hich ha- been t ran-nut t mi: the current, but now has its end pu-hei] from the point of contact. Tin- stops the current; the ha n iiner i< ilra \\ n back to it - original posit ion by the act ion of 1 he spiral sprmtr: the con; aci -bearing -prnm' iroes back to its po.-ition. where an electric contact i- a^ain made between a platinum surface on the spring THE .r-RAY 729 and the platinum point of a screw placed there. The current flows again ami the same interruption is produced. The limits of the use- fulness of such an interrupter for .r-ray work arc an s-inch coil with a current of 10 volts and an average of (i or 7 a mperes and .'!'_' ml errupt ions per second; or 1 volts and an average of 10 amperes and '.'> interruptions a second. \\ ith the first speed of interruption good hut not the most rapid .r-ray work can be done, lor instance, with a battery ol storage- cells giving 1 - volts a radiograph of the pelvis can be made in H\ min- utes. 1 Hull-frequency apparatus also works well with such a current. A condenser is necessarv with a coil supplied with such an interrupter. The rapiditv of the interruptions is partly self-regulating; depending upon the strength of the electromagnet and hence upon the strength of the current and the amount ot self-induction in the primary coil; and partlv adjustable by changing the tension of the spiral spring connected with the hammer, and by turning the screw against which the hammer presses when at rest. Advancing thi> point makes a shorter excursion or to-and-fro path for the hammer and makes the interruptions more rapid. The adjustment of the screw which bears the point of contact is not particularly for the regulation of -peed, although it may affect the speed incident allv. and the other speed adjustments may have to be altered to correct the change made by it. This screw is intended to be turned when the contacts seem to be imperfect. The Carpentier interrupter, like all others of the vibrating type, must be used in the air. and is limited to a strength of current which will not produce an arc between the points of contact when thev are separated. It cannot be submerged m anv liquid. To use such an interrupter with the 110- or 220-volt current a motor generator or rotary transformer would be required giving a current of is volts and s amperes. A voltaic battery of or s large bichromate of potash cells may be used. A storage-battery of or S cells would also operate an .r-ray coil provided with a Carpentier interrupter. A condenser is a necessity with this type of interrupter, and an ad- ju.-table resistance or rheostat affords the most convenient means of regulating the strength of the current. Other interrupters are described at p. 854, in the section on Radiog- raphy. REGULATION OF THE PRIMARY CURRENT The strength of the current varies directly and the rapidity of the interruptions inversely as the sixe of the pin-holes in the Caldwell interrupter, and it is necessary to have a rheostat to reduce the strength of the current in cases in which the full current transmitted by the mt errupt er is not required. The greater length of platinum point exposed in the YVehnelt inter- rupter the heavier current is transmitted. Other interrupters also regulate t he current st rengt h to a cert a in extent . It is always desirable, however, to have a separate regulator, called a rheostat. The Rheostat. Two general types of rheostat are suitable for. r-ray apparatus. ( )ne is made of rather fine iron wire wound upon a long insu- lated cylinder, a rack and pinion movement chanties the point of contact to different turns of the iron wire. The current in this way may be allowed to pass with scarcely any resistance or gradually the whole 730 MEDICAL ELECTRICITY AND RONTGEN RAYS resistance of the 25 yards of iron wire may be turned on. This type may be called a drum rheostat. The other type consists of an insulated iron plate across the back of which an- fastened 1") strips of sheet iron or of (ierman >ilver. each several feet long, but crimped so as to be fastened between binding-posts, only !) or 10 inches apart. With the insulated handle turned all the way over the contact is made between points which permit the current to pass with more or less resistance. Khcuxtdt i >('/ //(/// tin Author' m l~-inch Induction-coil. The rheostat has a number of different steps. Xearesi the short-circuit position or the position where no rheostat resistance is introduced there is a step with a resistance of 0.4 ohms. Following this there are three other steps of 0.4 ohms each: 2 of 0.5 ohms each; 2 of 0.7 ohms each: 2 of 1 ohm each: 2 ot 1.75 ohms each, and, finally. 2 of 2 ohms each. For radiograph}' with a Wehnolt interrupter the author cuts out all the resistance from the rheostat; but with the Wapplor mechanic inter- rupter he employs a rheostat resistance of about (i ohms. For radiotherapy or S ohms rheostat resistance are employed with the Wehnolt interrupter and 12 or 14 with the Wapplor mechanic inter- rupter. The rheostat resistance' required for high-frequency currents is usually Hi ohms if the Wapplor mechanic interrupter is used, or 12 or 14 ohms with the Wehnolt interrupter. Turning the handle back, the current must pass through one or more lengths of crimped iron, and is reduced in strength by the resistance encountered. The further the handle is turned in this direction the irreator is the resistance and the less the strength of the current which is allowed to pass. Fither kind of rheostat, depending on the fact that iron is a poor conductor of electricity, becomes heated in consequence of the friction encountered by the current in passing through it. The greater the resistance introduced the greater the heat, but this does no harm, pro- vided the capacity of the rheostat is not exceeded. The gridiron rheo- stat i- made to carry the heaviest current.-. The primary coil is of heavy, well insulated copper wire (Xo. 12, B. W. S.i. and is wound around a core consisting of many rods of soft iron (Xo. :>0. B. W. S.). The iron core is about 2 inches in diameter for a 12-inch coil. It become.- a powerful electromagnet and adds very much to the amount of induction. The wire should be wound like thread on a -pool, all the turns being in the same direction, but in two or three 01- more layers, depending on iho si/o of the coil, and it should be provided with several binding-posts, by mean.- ot which the conduct- inLi curd- may be attached in such a way as to vary the path that the ciHTenl must pa-- through. Thus the current mav be made to pass through the entire length of the wire in the primary coil as a single continuous skein, or it may pass through all the layers but one or two. or perhaps onlv through one layer. In a portable outfit designed by ' 'al< I well and made by \ an I lout en and Ten Broeck . the variation is onlv from one continuous skein to four \ produce v. hat i.- known as variable si n will be -een later that the mamp import ance in rai liography. Sell m from a i lirect or coi onh iviii'_ r an iron core. THE X-RAY 731 According to Alltcrs Schoenherg, the primary coil fora 50-cm. coil, that is. one designed to give a heavy discharge across a space of 50 fin. (17 inches), should consist of six layers, giving a variation of from 1(30 to 1000 turns. The vibrating interrupter of an .r-ray coil may be placed in air compressed to 2 or 3 atmospheric pressures and this will prevent arcing, according to Januszkiewicz (IMiys. Zeit.. \o. 12, I'.)OG). A condenser is required for an .r-ray coil when any kind of mechanic interrupter is used. It is made up of sheets of tin-foil about s inches square separated bv paraffin paper or mica. It is necessary that the insulation between the two sets of 50 to 100 sheets should be perfect, because otherwise the primary current would be short circuited and would flow through the condenser instead of through the primary coil. To secure this perfect insulation it is best to boil the condenser in melted paraffin until every bubble of air escapes. The secondary coil is built up around a hollow cylinder of mica acting as an insulator, into which the primary coil may be slipped and which has walls from } to \ inch thick, depending upon the sixe of the coil. The copper wire is as fine as a hair and is all wrapped with thread. It is coated with melted paraffin as it is wound on bobbins, each of which contains thousands of turns. In the author's S-inch portable coil there are 12 pounds of No. 34 wire. The bobbins are in the form of thin circular disks with a hole in the center. They are all strung on a mica cylinder and are separated from each other by disks of hard rubber. The number of these bobbins may vary from S to SO, depend- ing upon the sixe of the coil and upon the labor that the manufacturer puts into it. The whole coil is sometimes kept permanently immersed in oil as an insulator, but the more usual practice is to pour melted paraffin over it, which on cooling forms one solid mass. The secondary coil terminates in two brass binding-posts to which are attached the variable spark-gaps leading to the conducting cords of the x-ray tube, and, what is very important, rods for determining the spark resistance of the tube. The Sprintremeter. This consists of two rods attached to the two poles of the coil, and if they are approximated while the .r-ray tube is in operation the distance at which a spark will leap between them is called the sparking length of the tube and indicates its resistance to the passage of the current. This is one of the elements in determining the condition of the vacuum in the tube and its fitness for various radiographic and therapeut ic purposes. The author's office .r-ray apparatus consists of a 12-inch coil with amperemeter on the primarv wire, two Wehnelt and two modified ('aid- well interrupters, a \\appler wheel interrupter, gridiron rheostat, primary coil with variable self-inductance, secondary coil with the author's adjustable spark-gaps, combined with a d'Arsonval appara- tus tor high-frequency currents, which is connected with the coil by simply t urn ing t wo brass rods into contact wit h the poles of the secondary Cl 111. Portable x-ray outfits for use on the electric light circuit should not contain any single piece weighing more than 50 pounds. The author's own outfit for use with 110 volts direct current consists of a secondary coil measuring S.\ X S*, X 17 inches and weighing 50 pounds, a separate primary coil with three different windings weighing 17 pounds, a Wehnelt <>- MKD1CAL KI.K< TKiriTY AM) H()NT(iEN HAYS interrupter in a box measuring S X S X ' inches, with an additional 3 inches for its screw adjust ment of the platinum point and weighing 13 pounds without the fluid, which is added at the patient's home, and a carrying case for two ./'-rays tubes and four .r-ray plates in envelopes. This case weighs 111 pounds and measures S.\ X bV> X 20 inches. The tubes are clamped, inside and the plates may lie any size up to 1-4 X 17 inches, and are in an entirely separate compartment. This carrying case was made for me l>y Mr. Percy Russell, of New York. The tube holder is fastened to an upright which screws into one pole of the coil. The use of the \\ehnelt interrupter enables us to dispense with a rheo- stat and an amperemeter. Tests made at the oflice show that when the apparatus is set up complete with a oO-cm. heavy target Miiller tube and connected with the 1 10-volt direct current and the point of platinum, which is of '2 mm. cross-section, is just flush with the porce- lain the current is \\ amperes, regardless of what primary winding or hal 'I'-Li!'* 1 '- 'it vacuum may be used. K.-trh complete turn of the in- -ulated knob which regulates the \Yelmelt adds 1 mm. to the length of |ioiii1 exposed, and by I'eference to a written table the ra'_;e i,\ the curi'eiit with various primai'v \\'indiim~.- and with tubes nl ditlefent ile^rees ot vacinui) ina\' be read at a U'laiice. Tiii.- i- svitli a r-incii tung.-ten target tube with medium high vacuum. THE X-RAY 733 With the same tube, but with the lowest vacuum suitable for .r-ray work and with the same conditions as to primary winding and interrup- ter, the amperage is found to be about one-fifth "Tenter than the figures given above. At a patient's house or hotel it will be found wise not to employ more than about 12 amperes for the thicker parts of the body, and (i or !) amperes with Xo. 3 winding would be excellent for radiograph- ing the extremities, and even a weaker current would be used for treat- ment . If there is no electricity in the house to which you are going the current may be supplied from an electric automobile, or the above outfit Portable .r-rav and i -frequency apparatus of t he Tola type (Hyfrex Xo. 1). can be modified by omitting the Wehnelt interrupter and taking one or more storage-battery ceils and a vibrating interrupter and condenser. The Wappler mechanical interrupter and a rheostat make a desirable substitute for the Wehnelt interrupter in a portable outfit. A desirable portable ilcftric /< rotor I'm' .r-rni/ m >//, consists in part of the I )elco light set. comprising a gasoline engine and a dynamo which is to be specially constructed so as to give an alternating current, an- other unit comprising a high tension transformer for .r-ray and a low tension transformer for (he filament current of a Coolidge tube. This was used by the [' . S. Army in the World War. Portabh x-Ii(i\i Outfit of thi Tt*! inches in thickness. It weighs 38 pounds complete. The 1 discharge 1 is an alternating one and, therefore, does not exe-ite an ordinary .r-ray tube 1 as we'll as if a KuhmkoriT coil we're 1 useel. A high-fivqiiency .r-ray tube 1 (Fig. 4(it'>), however, give 1 ? an exevlle-nt radiance, suitable for all therapeutie- purposes and for the lighter forms of radiography. The apparatus is made for either the alternating or direct e-urrent. Hi:. -liiO. Minn-frequency .r-ray tube for use when the secondary current has an altcr- Voltage of Different Secondary Spark Lengths. Walter 1 reports the following voltages with alternating currents, induction spark length, in the open air: Maximum Voltage. 10 fin. 20 rni. 30 cm. 40 cm. 5()cm. t)4,()00 IDS, (MM) 14S.OOO ItiS.(MM) 21f',()()0 My own observations with the Cabot direct current, high potential converter were made 2 with a gap between two loops of wire, (laps of 1 and 2 cm. showed less than 10 kilovolts, the first graduation on my voltmeter, (laps of 3 and 4 cm. showed about 10 kilovolts, and gaps of .") and (' 4, 70, 72, and *0 kilovolts. In every case there was a drop to less than one-half the Voltaire durinir the passage of the spark. Spark lengths with a transformer, measured between moderately sharp points, are usually about as follows: . Volt- Kiovolt- , (MM) If).(MM) 15 "), urn 6 rn.(MM) 70 Power Apparently Generated in the Secondary Current.- -Based upon the calculation of 100,000 volts and 2 milliamperes the power irenerated by an .r-ray coil would be .">00 watts, and with 100.000 volts and 1 ." milhampercs the apparent result would be 1 .")()() watts. As the power ot thf primary or exciting current passing through the coil 1 I 'nri -<-li n't, ;.ul ' (li'in ( Icliicte -li-r Kocnt p-n>t ralili n, < let. L'."), l'.M)4. - Mav > lli:i. THE X-KAY 735 may bo only about 500 watts and 1500 watts respectively, and since we know that nearly half of the power in the secondary is wasted in the form of inverse; discharge which must be suppressed, there is apparently a greater output than intake; of power. Of course this would be an impossibility, and the explanation is found in the fact that the meters indicate the maximum of the successive currents rather than their average strength. A transformer, with a primary current of 15 amperes and 220 volts or 3-2 kilowatts, may yield a secondary current of 10 milliamperes, and approximately 1 horse-power or 740 watts is delivered to the Coolidge tube when the factors are 5-inch spark, 5(5,000 volts, and 10 milliamperes. And with this, characteristic radiographie exposures at 23 inches and using a Seed x-ray plate would be: hand, one second; elbow, two; ankle, two; knee, four; shoulder, eight; chest, ten; hip, twenty; head, laterally, twenty-five; frontal sinus, fifty seconds. The energy delivered to an x-ray tube 1 increases in direct proportion to the milliamperage and also to the voltage 1 ; but the intensity of the resultant x-ray measureel by fluoroscopie- brightness and photographic e'ffee't varies directly in proportion to the* milliamperage and to the square of the voltage. In e^ae'h case the high tension current delivered to the x-ray tube is referred to. If erne* has apparatus which allows a constant direct current to pass through the x-ray tube 1 anel maintains the resistance* or spark equivalent or voltage at the desired value, then the number of milliamperes shows exactly the strength of the x-ray generated. Without these factors the milliamperemeter is useless anel the whejle application of the x-ray be- e'omes a matter of long experience or e>f dangerous guesswork. Amperage of the Secondary Current. The currents generated by the large induction-coils for x-ray and high-frequency currents in medical apparatus anel for wireless telegraphy in commercial apparatus have very high voltage and also very appreciable amperage. A 12-inch spark means, according to some calculations, 100,000 to 300,000 volts, anel the strength of the current which such a coil will send through the enormous resistance of an x-ray tube is from 1 to 15 milliamperes. The currents are rapidly alternating and, like most other induced currents, consist of waves, each of which has a maximum anel a minimum strength. The meter shows approximately the maximum amperage without very much regarel to the average strength, either of the impulses alone or of the impulses anel pauses combined. Hot-wire meters inelicate the current strength regarelless of its alternating polarity, while electromagnetic meters (galvanometers) are of greatest value when the conditions are such that the 1 impulses in one eliree-tion are prae'tically suppressed. The amperage on short-circuit is much greater, anel when the poles are brought within a certain number of inches of each other the scries of sparks becomes an actual flame which will readily set fire to paper. The length of the flame varies with different makes of coil, anel its am- perage is about equivalent to that of a continuous current of about 10 or 20 milliamporcs. The maximum of each impulse 1 of which the short- circuited secondary consists is probably very much greater than 10 or 20 milliamperes and the current will fuse a fine wire which is not per- ceptibly warmed by a voltaic current of thai amperage 1 . When the two poles are 1 disconnected a spark will pass to a person's hanel held near either pole and it gives quite' a sharp sensation accompanied by a reflex <>!) MKDICAL KI.KCTHiriTY AND H()NT or2(; parallel copper thread-. Tlie -ilk insulation keeps 'Vires in a flexible cord which has no tendency to kink or tangle. I I"-' 1 <'"fd- -hoiil.1 be wound upon suitable spring reels for attachment '" l>"l; s "' ;| " ''- | ' ;|V <"'' [!'> "'"- The cords may he drawn '"" '" '"'.' desired distance, remain taut, and are wound up automatic- THK X-HAY 737 ally whon unfastened from (he .r-ray tube. These wires should be kept from contact with other conduct in"' substances because the current will pass right through the insulation and damage the cord by burning a hole in the silk. Such an occurrence does not ruin the cord at all. because the insulation was never intended to be relied upon, and a few holes in it do not matter. Perfectly bare wires in the form of a spiral spring are cheap and convenient as to stretching out to any desired posit ion of the tube, but t hey get tangled up in a most aggravating manner and are, therefore, not to be recommended. Flat steel tapes in an automatic reel are serviceable, but not so easily managed in all positions of the' tube as the covered wires above described. The ordinary insulated conducting cords covered with gutta-percha and cotton or silk are not suited for high-tension currents. They are heavy and comparatively lacking in flexibility and, worst of all, they will not stand the electric strain for an instant if the two wires happen to cross or if one comes into contact with a good conductor, and they cannot be handled by the operator or be allowed to come in contact with the patient. They cannot be wound upon an automatic reel and the manipulation of the tube with reference to them becomes quite a study. Rubber and woven silk or cotton will not resist perforation by these currents, and after having once touched another wire in operation with the .r-ray such a cord loses its insulation at that point and is destroyed for any useful purpose it might have served as an insulated wire for primary currents of 110 volts or less. These wires are clumsy and their in- insulation is useless for the higher voltages. The second good class of conducting cords for .r-ray work are those made with a sufficient coating of shellacked cloth or plaster of Paris to be impervious even to these high-voltage currents from small .r-ray coils. They have an outer covering of woven silk and measure about \ inch in diameter. They are comparatively light for cords of such large diameter and slightly flexible, enough to bend into a circle 4 inches in diameter, but should not be bent at a sharp angle for fear of breaking the insulation, \\hen connected with an .r-ray coil and tube in operation they may be held in the hand or may even be crossed. /. c., allowed to come in contact with each other. The latter is productive of a sort of static bree/e discharge between the two cords accompanied by a rustling noise and violet light. It is not destructive, but it is unwise to allow it to continue. The author used to employ t he>e conducting cords in all cases where special treatment .r-ray tubes were held in the hand. The small cords on the automatic reels are so convenient that they are now used for nearly all purposes, the heavily insulated cords being reserved for application of the .r-ray in the vagina where there would be danger of the wires touching some part of the patient. This could not be allowed to happen with the lightlv insulated wires, but with these other> it is not annoying. It . A'-ray S, where t he inverse discharge or make current in the secondary coil is above the neutral line and the direct or break current is below it. The rate of revolution of the mirror being known, we may calculate from the tracing the number of inverse and direct discharges per second. The proportion of the time occupied by each as compared with the total of each period or cycle is indicated and also the relative strength; but this method does not directly measure the voltage or amperage of these cur- rents. Thi< method is applicable also to the study of high-frequency cur- rents. The following is quoted from the first edition of this work (1910): "A thought has occurred to the present author that this method of studying induced currents will ultimately lead to the discovery of a per- fect apparatus for the production of the .r-ray. The ideal current, according to my view, is one which will maintain a constant difference of potential between the two poles of the .r-ray tube instead of the rapid change from high to low potential or even to an inverse 1 potential as produced by present methods. The ideal chart according to this view would show a uniform elevation instead of the waves in the present chart. This might occur from each individual direct discharge being length- 740 MKDICAL KLK< TKKITY AND H( ).\T( JKN HAY ended by self-induct ion or by add it ional capacity in t he primary or in t he secondary circuit, or by increased rapidity of interruptions; and in either case it pre.-uppn.-e- the complete suppression of the inverse discharge. The additional capacity might, for example, be a con- denser, ot which 1 he t wo s urtaces or sets of met al sheet s were of enormous extent. And it such a conde v nser were placed in the secondary circuit the insulating plate.- between the two sets of armatures would have to be of mvat thickness and impenetrability. The only ideal generator of r-rays is possibly radium. The .r-rays and other radial ions seem to be sent out from radium under the influe-nce- of a constant and uniform force, just as heat and light ray- or waves are sent out from a body that has been heated while hot and is kept at that temperature bv a uniform source' of heat. * >f course, the heat is given out as vibrations, but these are millions ot times a second and are like the r-ravs from a tube in which the two electrodes were, according to the author's ideal concep- tion, maintained at a uniform difference of potential. Let us imagine a hollow metal ball (Fig. liiid with such thin walls that it will respond to the very slightest imaginable variations in temperature acting for the shortest time, and have this heated by a gas-jet the pressure of which varies from its maximum down to zero, or which may even be replaced by a blast of cold air. Then the heat vibrations would be sent out in varying quantities, and if the variations in the source of heat were very great and rather slow there would IK- perceptible changes in the liu'lit and heat given out by the hot metal halL ball. We- know that the wave lengths of the liii'ht and heat vibrations would also vary with the temperature. If the variations were very rapid and uniform they might be imperceptible and the metal sphere might seem to be giving out a uniform amount and quantity of heat and light, although in this imaginary case of a metal re-ponding instantly to every variation in the source of heat the light was rapidly varying from its maximum quantity to y.cvo, and its wave I'-nu'h was al.-o varvmi:'. and the variations in the heal sent out were [er. Su'-h an apparent uniformity of heat and li^ht emission in nee of extreme rapidity and umionmtv of variations is atialo- best conditions we are at present able to secure in the pro- he r-rav. At present the radial ions from an .r-ray tube are vibrations of a u'l'eat man v different wave-lengths and phys- -iolotric properties. \\ ith the ideal condition of a uniform ifference in potential between ! he two electrodes of an e -! 1011 Id surely be able t o secure a uniform production of rays probablv be able to produce r-rays all of tin- same \vave- . ate tin- vvave-lenii't h according to the de^ri-e of pene- rtie- desired. This would correspond to a metal isolutelv unitnrm ion ' >f a mix' ire i ical and pi and ;i an ; ::.:.: i ' -Tihen an un\"ar\'ing gas- roin a lube a! the present lime may be regulated ponderance i>i ray- ni a certain wave-length, but lid of : In- scale to t he ot her, ' | >a -s ( hfoiigh a -licet of some rav.- of Tin: .r-KAY 741 another quality. This would not bo necessary if it were possible to excite a tulie so thai all the rays were of the desired quality." These pages wore read l>y Messrs. Sewall ('a hot and Joseph T. Shaw, who were seeking an improved ./-ray u'onerator, and after SOUK; yea;'- <>l experinietitat ion and many consultations with the author they have produced a generator of a direct current of high potential and of practically unfluctuating voltage. This is described on page 7"j(). Induction-coils for Very Heavy Currents.- Coils have been constructed (1!H)7) by the Voreinigte Kloktrotochnische Institute, Frankfort and Aschafl'onburg. producing an abnormally powerful second- ary discharge. They are said to be capable oi forcing 20 to 40 milliam- and through which the usual type of "oil will onlv send .', to 1 milliam- peres. They are guaranteed to produce a chest radiograph in from one to ten seconds without an intensifying screen and are said to produce pelvis pictures m two or three second- under favorable circumstances. These figures are for a coil in which the primary spool is -10 inches long and the distance between the secondary terminals is about b'5 indies. It weighs about 1")0 pound.-. 1: is very important to remember that a powerful current may be passing through the primary, as indicated by the amperemeter, and a relatively heaw current through the tube, as indicated by l he mi 11 (amperemeter, and st ill produce no ./'-radiance at all, or so defective a radiance that only the poore-t sort of picture could be made, and that would require an excessively lonir exposure. It is easv for the experienced eye to note the defect either with or without the fluoroseopo. To determine the cause and how to remedy it are some- time- matters of great technical difficulty and it is to assist in this that the many details in this chapter have been written. Radiography with a Single Impulse. The current through a coil or tran-former is turned on and is immediately cut off by the blowing out of a cartridge fuse. A single break discharge is thus produced which excites the .r-ray tube for an instant. The Polyphos ( 'o. have a patent upon an outfit in which there is so little resistance that at the single contact there is a tremendous flow of current and an extraordinary de- velopment of .r-ray power at the break. It is thus possible to take a radiograph of a crying child. YVappler, in this country, is about to manufacture a coil or transformer of this type. Rapid Radiography with Several Parallel Wehnelt Interrupters. This method is said to have been devised by (iroedel. of Xauheim. It is applicable to an ordinary induction-coil and consists in connecting the positive electric-light wire with three large platinum points, which may be in a -ingle large jar or in three separate one-. There would be a sin- gle !ar0 volts is used and a primary current of (10 to ( .H) ampere-, -ending a secondary current of 20 to .')() ma. through the .r-ray tube. An exposure of one-fifth to one-half second produces an excellent radiograph of the chest when all the con- dition- are favorable. A heavy anode tube is required and a quick break -witch to prevent arcinu when this very -it'onii current is turned off. An automotic circuit-breaker, cuttinu' off the current alter the proper time, i- a vorv desirable addition to the outfit. (4'2 MKlMt AI. KI.KeTKHlTY AND KoXTCKX KAYS The coil has to be specially adapted to this purpose, in order to secure much increase in .r-ray power by the addition of one or more extra AVehnelt interrupters. The Tesla High-frequency Coil for x-Ray Production.- Any alter- nating electric-light current may be connected directly with the pri- mary of a Tesla transformer, and two small condensers highly insu- lated by immersion in oil have a spark-gap between the two primary armatures and their secondary armatures are connected with the primary of the spark coil. A small .r-ray apparatus of this type would have about tiO turns of ]\o. IS gutta-percha-covered copper wire for the primary and about MOO turns of No. MO silk-covered "magnet" wire for the secondary. The terminals of the latter are connected wit h t he .r-ray t ube. If the alternating elect ric-litrht current is not available the direct electric-light currents may be changed by a rotary transformer, and the alternating current thus produced may be used to actuate a Tesla coil. An .r-rav tube lights un with the discharge from a Tesla or high- wire- le.-id ID this frnm :HI indil'-tioti-eoi] whieli is n<>1 >ln>wr higli-l're(]iieiicy apparat u.-. but they o no gve ratus of the -nine urade upon the oilier principle. The reason for this i- the alternating chara . Neither pole \ the apparatus can be considered the negative pole, and hi- means a very ureat \\a.-te of po\\er a- compare induction-coil. The latter i more pmvertul at the moment that the pnmar\' current i- l)l'oketl that the Huhmkortt coil ha- distinct polarity, and one pole can be considered e ce o -' Vi and t he older I he pi >-\\ ive t el THK .T-HAV 743 Fig. 471. Step-up former: P, primary; >', ? arv. An ordinary .r-ray tube with its cathode only connected with the ( hulin resonator, adjusted to give a 4-inch eflluve, produces a moderately good .r-ray. No other connection is made with the tube. The current traverses the tube not by leakage from its anode extremity, but by back-and-forth surging. The gas in the .r-ray tube acts as a condenser. Unrectified Transformer as x-Ray Generator. The construction is simply that of a step-up transformer without moving parts, if one ha? the alternating electric light current, and it requires only tin a motor generator if one has the direct elec- tric current. Some .r-ray tubes, notably the radiator type of Coolidge tube and the Renifar gas- filled tube, are so constructed as to trans- mit current in the proper direction and to suppress the inverse current more or less completely. The portable outfit described in the I". S. Army .r-Ray Manual' and used by our Army consists of an unrectified trans- former and a radiator type Coolidge tube. The High-tension Transformer. A pioneer apparatus of this form for the production of the .r-ray was introduced by (laiffe, of Paris. To make a transformer, we take a soft iron ring (Fig. 471 ) and wrap a part of it in several turns of insulated wire" through which passes the primary current, and wrap another or the same part of the ring with a number of turns of insulated wire in which the secondary current is to be generated. Fvery time the current starts or stops in the primary turns of a wire a current is induced in the secondary turns of wire and the voltage of the t wo currents, primary and secondary, is directly proportional to t he num- ber of turns that each wire makes around the iron ring. This is a matter of ("very-day use in electric engineering, and if the transformer is one for changing from a low to a high voltage the appliance is called a "*t< p- iiji" Irtntxfnrnifr. The appliance for changing from a high to a low volt- age is called a "step-down" transformer. Transformers made for practical use in electric welding and lighting and electric power genera- tors in factories are so perfect that the voltage is changed either up or down with the loss of only )] per cent, of the power. ( lail'fe's transformer for .r-ray and high frequency use must be run on an alternating current, and where only a direct current is available this must be changed to an alternating current by means of a dynamo machine known as a motor generator. The primary current is regulated by a choke coil, or inductance, or a liquid rheostat", and is measured bv an amperemeter and a voltmeter. From the transformer secondary wires pass to the pules from which t he connect ion is made wit h t he ./'-ray tube. ['he strength ot the current passing through the .r-rav tube i> indicated by a milliainperemeter placed directly in the circuit supplying .r-ray tube. The discharge from the transformer being an alternat- one. two vent ril tubes are introduced on t he secondary circuit to take all the discharges in one direction, A ventril tube is attached to i pole ot the secondary and these two tube- are connected. They s form a -hum circuit through which one set of discharges pass, while .r-ray t ube. A vent ril t ube. it \\ ill be lavinir much the same character as an 744 MKDICAL KLKCTUiriTY AND KONTt ; K\ HAYS -ray tube, but with a simple cathode and anode and no anticathodo. t is neci'ssary that it should l>e provided with a regulator of its degrees f vacuum, \\ith ( iail't'e's apparatus it is necessary to have a set of ondensers insulated by compressed air, and there is also a liquid re- -tance on each of t he secondary wires. In l hese resistances t lie current a- to pa-s between a platinum and a lead point through dilute sul- hunc acid. The condensers and these liquid resistances product 1 uni- nnity of discharge by preventing self-induction in the turns of the condary wire in the transformer from a sort of backing up action hich would occur especially in connection with a high-frequency sole- ' !'.< { i >r resonal or. The principle of the transformer for actuating an .r-ray tube is not a ;ie\v one. but it gives Mich uniform and powerful currents that with 1110*1 manulad urer- it has now n ( .'2l)i displaced the more uncertain ou'fiis thai depend upon an interrupter and an induct ion-coil. fi.iiffe's tran-1'ormer apparatus i Fig-. 172 17 I 1 , tor high-frequency current- and the .r-ray, depend- partly upon the use of compressed air or ii;i- as a dielectric or insulating medium, and partlv upon the intro- duction ot re-!-tance- or inductance- in the prmiarv circuit, or derived ir'om the -econdary circuit to prevent the formation of an arc at the ["he fir-1 i- ba-ed upon the supposed lad that compressed air or other L r a- i- a better iion-condudor ot eflluves or disruptive discharges I han ua-e- a ' i u'd nri r\ pressures, and thai it has t he advantage over solid m.-ulation like parailin or liquid in-ulation like pet roleum oil, that it is neou-, whereas, a local delect m these others might i ice M]-. Tin- po-Moihi v o] a change occurring in the pressure of air inside THE X-ltAY the ease containing the transformer produces ;i danger to (ho apparatus from a reduction in the insulation which is guarded against by a safety device. There is an orifice at a certain part of the case which is closed either by a flexible membrane or else by a piston. If a leak occurs the reduction in pressure will produce motion in the diaphragm or in the piston, and this motion actuates a quick break switch which turns off the primary current. 'The connection between the piston or the membrane and the switch may be a purely mechanical one, the motion l in which motion produced by th elect ric contact . and the current so turned on operates a relay which causes the circuit breaker to act and cut off the primary current . Tin* suppression of the arc which tends to form at the spark-gap is a matter of experi- ment with different combina- tions of inductance. (Col e owern of the pressure makes an \vhoso self-induction produce a counter-electromotive force at the proper moment to oppose the break spark, capacities whose function is like that of the condenser of an induction-coil to receive the charge generated by the increased electromotive force when the current is broken and which without a large capacity to receive it would over- charge 1 the two poles of tho spark-uap and maintain an arc.) These capacities are connected with the secondary circuit. Resistances may be placed in the primary circuit of a transformer which v. ill have a similar eifcet . The mag; lit udo of the capacities and of tho inductances to be introduced varies ;ieeording to the nrecise conditions, and in some 7-lli MKDICAL KLKlTKK ITY AND K(")NT(; KN HAYS cases of a transformer with suitable resistances the other two means may be dispensed with altogether. Malaquin and Charbonncau have constructed a transformer giving 200,000 volts. It has two secondary circuits around a closed magnetic ring. Provided with a rectifier, it is said to excite S .r-ray tubes in series. Alternating Current Generator with High-tension Rectifier for x- Ray. At the present writing (101!)) this seems to be one of the most desirable types of .r-ray generator. A transformer is used which pro- duces an alternating current of 10.000 to 100.000 volts and is actuated by from 2 to 10 kilowatts, depending upon the amount of primary cur- rent. This is from 20 to 100 amperes of 110-volt alternating elec- tric-light current. This is the generator in Snook's apparatus, made by the Roentgen Manufacturing Company. Many others manufacture similar apparatus. If one has the direct electric-light current a motor generator is required to produce an alternating current. The current is rectified by a commutator in such a way that the top of each wave in the right direction is utilized. No ventril tube or spark-gap is re- quired. The amount of cm-rent sent through an .r-ray tube may be 50 ma. or more. The author has seen excellent radiographs of the chest which were made by the late Dr. Leonard in an estimated time of one-half second, and pelvic radiographs made with an exposure of two seconds. I)0th of these were without an intensifying screen. The thorax pictures showed the diaphragm and heart with clear outlines ap- proaching those obtained when a dead person is radiographed; they also showed the space between the heart and the diaphragm, which is usually demonstrable only by the fluoroscope. It is now practicable to make gastro-intestinal radiographs in one-fifth second. The greatest difficulty in the use of enormously powerful currents is going to be with the ./'-ray tubes. A continuous discharge of 50 ma. or more will develop a temperature of 2000 or :>000 K. at the focus of the .r-ray tube and fuse even iridoplat inum in a short time. Solid copper targets with tungsten buttons are excellent, and solid tungsten targets, as in the original < 'oolidge tube, are still more heat resistant. Secondary Rays from a Tube Actuated by Such a Transformer. It! a personal communication to the author I )r. Leonard expressed thi' belief that the unidirectional character of the discharge through I he .r-ray tube results m a radiance tree from secondary or vagabond rays, ;it: d that, therefore, no diaphragm would be necessary to cut off the-e rays ;,ij ( | secure nood definition. lie ~.-j\<\ that in renal calculus case- the amount of definition was so great as even to be confus- ing. This prediction has not been verified with gas-filled tubes, but is partiallv true with the ('oolidge tube. At the author's request 1 )r. Leonard tried the author's experiment in which a silver dollar was interposed between the ./'-ray tube and a penny, so that the latter vva~ IM the shadow of the former. The pennv was readily visible with thi- fluoroscopi and in a radiograph. This was also the case when the dollar was -imported upon a sheet of paper \\hich Dr. Leonard thought would cut of] -econdary rays arising from the tube. Hi- conclusion was that the ima'_[c ( ,t i he penny was produced bv rays which had passed -liver dollar. A piece of heaw the s;,||]e result a* the -i!ver dollar, but with more HI U'ed to the greater dil'lUs'ioii of the .r-ra v bv the lead TIIK X-RAY 747 in each case \vas 7 inches from the plate and its image showed no hala- tion. The author has made a number of very interesting experiments, from which he draws the conclusion that the vagabond rays are, most of them, not arrested by paper or even by heavy sole-leather, and that they arise under ordinary circumstances for all practical pur- poses from the glass walls of the illuminated hemisphere of the x-ray tube. Hi- experiments do not enable him to say whether these second- ary rays are due to cathode rays or x-rays from the focus on the anti- cathode striking the glass wall of the illuminated hemisphere, but hi- belief is that they are due chiefly to the impact ot cathode rays. In- verse discharge causes cathode rays to strike the iila-s wall of the tube and give rise to disturbing x-rays from parts outside of the illuminated hemisphere, and in this way add the blurring due to the secondary ray> 7-1S MEDICAL KLK( THiriTY AND KONTCJKN HAYS from the illuminated hemisphere alone. Xo amount of rectification of the current i< going to remove the latter source of secondary rays. The most practicable ways to deal with this are by the use of a diaphragm to cut oft 1 he -eciiinlary ra\'s and by 1 he use of an .r-ray 1 ube wit h a very -mall active bulb communicating with a larger one acting sim])ly as a gas container. The author's cellular radiating diaphragm gives good definition over a- wide an angle as mav be desired. It may be con- strticted to illuminale almost a hemisphere. Xo limitation as to the Mivngth of current and the consequent intensity of the radiance results Iron i t lie use of a diaphragm. 1 1 is contact diaphragm is especially useful. The use ot an .r-ray tube with only a small surface for the radiation of secondary ray-- while permitting of the radiation of direct rays through almost a hemisphere is also believed to be original with the author. Hut the gla>s i- so near the anticalhode that it would soften if heavy currents were used. The ( 'oolidii'e or electron discharge .r-ray tube obviates this difficulty by producing practically no .r-rays from its glass wall. Kny-Scheerer "Interrupterless" x-Ray Apparatus.- The Kny- Scheerer "interrupt erloss" apparatus, developed from Snook's inven- tion Fig. \7~>t. comprises a small stand upon which are mounted the necessary switches and rheostats and a cabinet, in which is a motor generator ( (', Fig. 47(i), a step-up transformer (T and h ', and c ' o t he liliode of the .;'-I'a V til be. 1 "rolll the ca t hoi le of 1 lie J'-I'aV t llbe 1 lie it i' e current passes to /'and .S'. which is now in :i line bet ween /' and /^,, h it passes to '/, which i- now the negat ive pole of t he t rails- The ',,','. lit delivered to the r-ray tube is unidirectional and pulsat- ing I iu. 1 77 . and is much less dest n let ive ol I ubes than t he all ernat ing discharge from an ordinarv induction-coil, as in ! ig. !7uppre>sing currents in the wrong direction. This wa> an advance over the (iris.wttntoT, which gave a series of -econdary currents in the right direction, but, of course, with a voltage varying from /ero to a certain maximum. The Cabot heterodyne, on the i (![ it rary . furnished a constant difference of potent ial at the terminals ot I he ./'-ray t ube. An oscilloscope in series with t he .r-ra v t ube showed a continuous luminous band in a revolving mirror instead of the series of tla-he- seen with anv previous generator. The .r-rav tube itself showed THK .T-KAY 751 continuous luminosity in a revolving mirror, and the .r-rays were believed to l>e approximately homogeneous, all being produced by electrons traveling at about the same speed under the impulse of an unvarying voltage. It was at this stage that the author was first visited by Messrs. ( 'abot and Shaw, and, while this was recognized as a distinct step toward his ideal, it seemed to him that too much power was wasted, and that the correlation of the various capacities and inductances was a complicated matter, and probably not subject to accurate regulation for the different voltages and amperages required for all radiographic and treatment work. l-'iir. li't. ( 'alxit high-potential direct current converter. Delivers t nfluctuating, VisiMe in t lie glass case is a lo\v volume triple-phase generator, the currei is Mepped up i>y t hree transformers, one for each phase, concealed in t he ha.- '. The high- tension triple-phase current reaches the .r-ray terminals through a connnut: tor visihle in the glass ca.-e. In another glass case on top the author has a high-tension interrupter and condenser, hy mean:- of \vhifh the current is catised to flow through the tuhe only half or only one-tenth of the time. This is for use in fluoro-<-opv and radiotherapy. The final development is the Cnhnf high- potential nnixfunt rnltage et of three transformers, connected in such a way as practically to torm a (Iramme ring, and if the same strength of triple-phase current is used. 7.V2 MKDICAL KLK( rUICITY AM) HO.VRiKX RAYS of course the soconciary winding at opposite ends of :iny diameter shows a certain difference in potential equal to that of any other opposite points. If the current were taken from any two fixed points of the secondary winding it would he a hiidi-tension alternating: current: hut collecting this secondary current from portions hy hrushes which advance at the same rate as the variation in the current secures an unrliietuating sec- ^ % t "-*** , HKg . *. r- ^ f " ., *tk I:' !--'i i niitpi! |i:incl fur Caliot Inch pfitcnti:il direct current converter: A, Mil- 1 '. nvolt inet-T: < ', primary iitiiliicter; I-., nuality ; r:it in of t ran>fonii:ition1 : , :. ' i- h ihandotied; I). i|iiatitit>' ire-i~t:uice reirul.'tinr li-\-cr: !'. (iperatinn irn nl -witi-li; II. -t'irtiiiiz '>\: I. automatic o\ rrload circuit breaker. : not -iiown. It may l.e-.-t for expo-ure- of frum one-tliirty-scfond to i] \ ,-r^ion < '>., lirookline. Ma.). ondai'y t'Ui'i'i-nt. The voltage is so ln3 primary current, and consequently thai of the secondary current, but, of course, with a certain adjustment of the apparatus the voltage at- tained will be higher the Teuter the decree of vacuum in the tube, and the number of milliamperes passing through the tube will be corres- pondingly less. (ienerally speaking, with an unfluctuating voltage, each 10,000 volts, corresponds to 1 degree Benoist, so that 90,000 volts indicate x-ray of about No. 9 Benoist, and the greater the number of milliamperes sent through the tube at this voltage the more quickly a radiograph will be produced or a given therapeutic effect obtained. Cabot's experiments show that with this voltage an exposure of 3400 milliampere seconds, at 10 inches from the skin equal 1 Sabouraud-Xoire dose. According to this estimate, if the anticathode were 10 inches from the skin and there were 34 milliamperes passing through the x-ray tube, an exposure, or a series of exposures, amounting in all to one hundred seconds, would produce a Sabouraud dose. And, again, if there were 3.4 milliamperes passing through the tube at the same voltage, representing the same degree of vacuum and the same quality of x-ray, an exposure of one thou- sand seconds at 10 inches from the anticathode to the skin would pro- duce a Sabouraud dose of /H Holzknecht units. Currents sent through the x-ray tube by such a generator must be prevented from undergoing oscillations analogous to those shown by the 1 10-volts direct current when supplied to an electric, arc with a condenser, and known as the singing arc, page 640. Oscillation stoppers an 1 , there- fore, provided, which consist of spirals of fine wire wound over hollow card- board cylinders. One of these is in circuit at each secondary terminal. An x-ray tube, with the proper degree of vacuum, excited by this appara- tus, shows no inverse discharge at all in the oscilloscope, and no spark- gaps or ventril tubes are required for radiography or Rontgenotherapy. But a tube with too high a degree of vacuum shows rings indicative of inverse discharge, and this is confirmed by the oscilloscope. These last two sentences apply also to its use with the Coolidge tube, inverse being shown by green streaks near the cathodal prolongation of the bulb. The apparatus consists of several different parts. At the bottom there is the transformer, or rather then 1 art 1 three transformers for pro- ducing the high-potential current from the triple-phase primary current. This section may be enclosed in wood and requires no attention. As originally constructed there was a variable ratio of transformation, but I have abandoned this in favor of a fixed relation between the number of turns in the primary and secondary windings. The section above this contains a motor generator of triple-phase currents, having hard- rubber revolving disks mounted upon its axle, and pressing against the outer edge of each disk are metal springs acting as collecting brushes for the high-tension current. This part of the apparatus had better be enclosed in glass, so that one may see that these contacts are all right. There are t wo oil-wells, which should be kept full to lubricate the bearings ot t his mot or generator. There is a milliamperemeter through which the high-tension current passes. There is also a voltmeter upon the switch-board winch in- dicates upon a dial the voltage at the terminals of the x-ray tube. This does away entirely with need for measuring the parallel spark- gap. The voltage may be somewhat varied by changing the strength of the current applied by the generator, but may be varied from le>s 4S 754 MKDH'AL ELKCTRICITY AND RoNTGKN RAYS than 5000 volts to more than 100,000 volts by regulating the resistance of the .r-ray tube. A number of fuses and an automatic circuit -breaker protect the ap- paratus from too heavy currents. All movable pails, including the motor generator of triple-phase currents, are fastened upon the 1 same shaft and. of course, move syn- chronously. The multiplicity of wires and of fixed and movable con- tacts gives such a perfect result that the oscilloscope detects no inverse current, and if tin 1 oscilloscope is viewed in a revolving mirror the image of the light is drawn out into a ribbon, not separated into a series of flashes, as is the case with an induction coil with or without a ventril tube, or with a transformer with a high-tension rectifier. The author's generator has been in daily use for several years, making thousands of exposures for treatment and therapy. It employs the 220 volts direct current controlled by a rheostat. The original trans- former unit was provided with means of varying the voltage by selecting the number of turns of primary winding, but this feature 1 has been dis- carded in the present transformer. On open circuit, without an .r-ray tube 1 , even the weakest primary current produces a secondary voltage of about HO kilovolts; stronger primary currents increase this voltage and a very strong primary current would produce a secondary voltage in excess of 100.000 with danger of breaking down the insulation in some part of the transformer. With about three-quarters of the rheostat resistance and a high degree of incandescence in the filament this generator will produce about 10.000 volts and send about 20 ma. through the ( 'oolidge tube. Chang- ing the degree of filament incandescence alone, we can readily secure 70 kv. and H ma., suitable for deep radiotherapy or for fluoroscopy. With a certain degree of filament incandescence produced perhaps by 1.2 amp. one-quarter of the total rheostat resi>tance may result in 55 kv. and i-Ul ma., suitable for radiography of the extremities and varying only the rheostat resistance to about one-eighth of 1 he total we may have t'5 kv. and oO ma., suitable for gast ro-intest inal radiography. And with only the last two or three buttons of the rheostat we may have* with the same filament incandescence produced by 4.2 amp. SO kv. and DO ma., suitable for very rapid gastro-intestinal radiography. (On occasion the author has made radiograph- with 150 or 200 milliamperes pasHn<:- tlirouuh the standard ('oolidge tube, but this is unwise.) Smt/t M ill i/n// j>< rc, if < forehand with a low-tension cur- rent until it transmits a current of 5 ma. or a little less with a pressure of about 30,000 volts. This may be done while the patient and plate are in position, as the exposure is so slight as not to affect the picture which is made by turning on the suitably increased power. The Coolidge tube had belter be regulated before patient, tube, and plate are all ar- ranged for the picture. We may regulate the resistance of the tube by varying the filament current so that with a certain power indicated by a certain rheostat contact (3 p. M. on the dial) we produce (10.000 volts and 30 milliamperes. Then turn off the current and change the position of the rheostat contact to 2 p. M. on (lie dial. We know by many previous observations that this will produce SO, 000 volts and an increased number of milliamperes, suitable for gastro-intestinal radiog- raphy. < )r we may know how to regulate the Coolidge tube without turning on the high-tension current, but simply adjusting the strength of the filament current. For instance. 1.2 amperes is about right for producing (10.000 volts and 30 milliampcres with the rheostat of the .r- ray generator at 3 p. M. or 70,000 volts and an increased milliamperage with the rheostat at 2 p. M. It is not best to depend upon placing the separate rheostat of the filament current at a certain position if this method is employed. For rontycnothfrapy (10,000 volt ratio is excellent, and for many 75l> MKDK'AL KLKCTKICtTY AND HONTCKX RAYS ruses either all the rheostat resistance may be used or about nine-tenths of it. Current values of 57.000 volts and 4 ma. correspond to about (> Benoist and produce an erythema dose of 5 H. in twenty to forty min- utes at a distance of 1M.\ inches from the anlicalhode to the skin. A new gas-filled tube will commonly light up at a tension of 20 kilo- volts and pass a few milliamperes. After a little use it may require 40.000 volts and pass 5 ma. The tube in the first condition will pass perhaps 200 ma. if sufficient power is turned on to maintain a tension of !0 kilovolts at tin tube terminals, while in the second condition a voltage of 00.000 will send perhaps only about 30 ma. through the tube. A tube which has been used a number of times requires a higher and higher voltage to light up and, unless the vacuum is regulated, will eventually reach the crank stage, where 100.000 volts may be required to break down the resistance of the tube, and where, with an unfluctua- ting voltage generator, a great rush of current may take place with an undesirable effect upon the tube. The moral is to test the condition of thi' tube with small current values and use the regulator rather than extremely high voltages for overcoming crankiness. The time of exposure with any of these voltage's will lie shorter the greater the number of milliamperes passing through the tube. The best current with medium and high voltages is 20 to 50 milliamperes. Within reasonable limits it may be said that with any particular voltage or penetration factor the same number of milliampere seconds will produce the same radiographie result. 3") to 40 kv. For great contrast in general work and not too thick region! 5 . 40 to 4") kv. For bone work where thickness of tissue is under 2 inches, for chest work on 100-pound subjects, and for general tissue detail using tin intensifying screen. 4.1 to ."iO kv. Suitable tor bone work on the extremities and chest work on 1~>0- pound subjects. "0 to HO kv. Best for kidney work on light Mibjeets. May be used for bismuth work on light subjects. Hood for general bone work on the extrem- ities. tin to 70 kv. Same as above with increasingly heavy subjects. TO to SO kv. Only suitable for hip. frontal .-inus. all bi.-muth work unless contrast between details is unnecessary. Mv own best results are obtained with 55 kv. as the lowest ; for teeth, except upper molars; for fin tiers; with (>5 kv. for kidney, gall-bladder, and general bone and lung work; and with SO. 000 volt- for Castro-intestinal a nd | nit'iima* K- -mil- work. I'.. i'n rn /ill .-> nt li'nfl i/>ii/'/ fluct unfitly \ oltotjc. A -mal! <-!iild'- hand may be radiographed with 50 kv.. the thymus L r land with till kv.; a thin adult fool with n'5 kv. and MO ma. exposure, three seconds at 2s inche.-.: a laru'er ISO-pound woman's abdomen with 'is kv., 10 ma .. and five or six second-. l'i-mut h expo-lire- are made with so kv., Mil nia.. an ml en-it ymg screen, and an expo-ure of one -econd or more, ilep 'ndiim upon the -i/e of ;he person. A very thick adult hip rei mire- si i i H H i \- { ,|| <_ I he "fhioro-ropic at tachment ." by means of which t he current passed throuirh the . -ray tube onl\" one-tenth of the total time of expo-tire, ac- coinpli-hed tnore than the mere attenuation of the radiance. It THE X-RAY <> 2f 00 3J 70 3f NO 4| >() 4* 100 ol X-ray Tube l\efushi or S inches between the arms of the coil it may prevent injury to the lube and alarm to the patient. The most satisfactory gas-filled tubes are the bianodal, in which the anticathode and the anode may be connected by a wire outside the bulb and really form a double anode. Such a tube does not blacken as quickly as one in which there is only one anode, and this feature is especially valuable while the tube is being exhausted on the air-pump. It must be remembered that a gas-filled .r-ray tube consists essentially of a bulb containing a partial vacuum with a positive and a negative wire carrying to it a current of very high potential and very rapid inter- ruption-. The current is, of course, said to be carried from the positive to the negative pole, no matter what their relative positions may be: but as a result of the current the cathode 1 rays start perpendicularly from every point on the front of the cathode 1 , which is commonly made concave so as to focus these rays upon a metal disk called the anti- cathode, where their impact causes the vibrations called the .r-ray. It is not necessary that the anticathode should be connected in any way with the electric current. In fact, in some tubes used especially for treatment there is no anticathode .at all, the .r-ray originating from the impact of the cathode stream upon the glass wall of the tube. This was originally the case in all .r-ray tube's. The essential functions of the target are so distinct from those of the anode, which is merely the positive- terminal, that it is always preferable- to call it the anticathode. In some tubes it forms also the only anode 1 , and in others it may be 1 used jointly with another anoele 1 . or may be 1 usexl as the 1 only anode, or may be entirely elise'emnevted from the e'lectric wire's. The 1 anti- cat he>de in any e-ase must be plac.ed at the focus eif the 1 cathoele mirror: the anode, howeve-r, may be 1 placed at any part of the 1 tube at a sufficient distance- from the cathoele. Sometimes it will be- found that a new tube 1 has quite a low vacuum and will give 1 better results when the 1 anode- and the anticathode 1 are 1 disconnected and the 1 connection made only with the 1 anticathode'. As a tube- become-s harder fremi use 1 it will often be 1 found desirable to comuM't the 1 anode 1 ami the anticathode. This point is of some 1 practical importance, but it will be 1 founel not te> be 1 of use 1 in all tubes. /()() MKIMCAL KLKCTHICITY AM) RONTGEN RAYS A very important fact, however, is that the use of the anode alone will frequently induce the proper production of the .r-ray in a tube which is behaving badly. The latter may be due to an excess of inverse 1 dis- charge. In the author's hands this lias been most strikingly illustrated in the case of a heavy anode (iundelach tube of S()-cm. rating, in which no amount of regulation of the vacuum or of the self-inductance or of the interruptions or strength of the current succeeded. There was an irregular green light which almost filled the tube with flickering circles here and there and a very poor .7'- ray was shown by the iluoroscope. This was all immediately remedied by disconnecting the anticathode and using only the anode for the positive 1 terminal, and the tube became sharply divided into a dark hemisphere and a hemisphere 1 fillenl with brilliant steady gtve'n light with a goeul .r-ray production. After sue'h a tube has begun to work properly the' aimde and anticathode may be founel to work very nice'ly when reconnected. As intimated above, there are 1 several either causes and as many re'menh'e's feir this troublesome condition, so that this disconnection of the anticathode is ne>t always the 1 thing neeeled. The line of demarcation in an .r-ray tube' may be' displaced forward by introducing a spark-gap in the e-ircuit. Charbonneau, 1 who called aTtentiem to this fact, finels that the displacement is the same- for any length of spark freun ^ mm. up. He' finels the same' amemnt of dis- placement, no matter whether the spark is on the line leading to the ane>de- or the- e-athoele- of the' tube-. Charbonneau finels that the- elegreo of penetration is reeluced 33 per e-ent. by any spark-gap, however short, em e-ithe-r line. A ]>erfecTly continuous connection must, theTefore-, be made without the' smallest spark-gap between the' peile-s of the .r-ray coil in oreler to se-e-ure the- maximum fie'lel anel the- maxijnum peiwer of radiation. Charbonneau attributes this ei'fect in part te> the entrane-e 1 e>f hydro- gen intf) the .r-ray tube by electric ine-ans. The hydroge v n is supposed to arise- freim the e'lee-trie- decomposition of wate-ry vapeir prese'iit in the atmosphere. He' puts this To practical use in reducing the 1 vacuum in an .r-ray tube which has ne> regulateir. The connections are maele in the regular way e-xe-e-pt that the-re is a small spark-gap on the line' leading to one pole of the- ce>il. A moderate e-urrent allowed to flow through the tube for half an heiur results in a material reduction in the' decree of vacuum as indicated by the- spintremeter and the Benoist ttidiochrornometor. The ''hi-avi/ anode" (meire properly "heavy anticathode") (1 mid cinch 1'ihc was an excelle'nt erne, the glass being eif the very best quality fe>r r-nty work, the- eismo-re-gulator being first class, and the 1 anticathode being shaped like a horse's hoof and presenting such a large mass of metal as to stand the heaviest curre-nt without fusing. ( Fig. 1X1 shows Then- is no perfect r-ray tube, however, and one 1 of the 1 this tube was that the shadow of the anticathode was dire-die)!! in which the picture' is gene-rallv taken. This fact that the anode was placed behind the anticathode, 1 other tube-, the anode was in the lone other tubes. Another hared by all "heavy anode ' gas-filled tubes; the great l.< !;,-i. lium. Si -ptcmlxT I.",. 1 <>.-,. THE 0--KAY 701 mass of metal liberated so much gas when overheated that the tube be- came temporarily useless the moment it got very hot. Some of the author's best radiographs were made with a 00 cm. tube of this type, but it seemed to him that this type of tube was a little more difficult to use than some others. If it was not in just the condition re- quired, it required all the skill and patience one possessed to adjust it. It has an osmo-regulator. a thin metal tube, usually of palladium, looking like a win 1 , which when heated by an alcohol lamp permits hydrogen gas to pass through its pores and thus lowers the vacuum (Fig. 482). Fig. 481. Gundelach heavy anode tube. Hanging a cuff of platinum over the osmo-regulator enables one to raise the vacuum (Fig. 483). For this purpose a loose cuff of platinum is put over the platinum tube and is heated on the outside by an alcohol flame. The heat must be intense enough to make the inner as well as the outer tube red hot and, consequently, porous to hydrogen gas. The excess of gas in the .T-ray tube escapes through the pores in the small red-hot platinum tube. A special lamp for heating an osmo-rcgulator has been devised by Paquelin, the inventor of the celebrated thermocautery which bears his name. By an arrangement of hand- bulb and container full of naphtha, "benzene, or gasolene a jet of carbu- retted air may be ignited and when Fit 4S2. Villard's osmo-regulator lowering the decree of vacuum. Fig. -4 S3. Raising the degree of vacuum. directed against the osmo-regulator produces the desired effect very rapidly. As in the case of the cautery, the lamp remains in full blast as long as the current of air is kept up by squeezing the hand-bulb. It is very important never to lower the vacuum to too great an extent. If the vacuum is only a little too low it can readily be brought up by run- ning the tube for a few minutes with a reversed current. A tube in which the vacuum lias become 1 too low from overheating bv the cur- <>_: MKDICAL KLKCTR1CITV AND KONT(iKN HAYS rent usually returns to its original condition if simply allowed to cool, and can hardly be made to do so in any other way. The "heavy anode" (lundelach tube cooled quickly and regained its original decree of vacuum very well. It seemed to be better adapted for radiography than for treatment, and would stand a secondary current produced by o() ampere- of primary current. Il would have been at that lime the author'- first choice for radiography if it were easier to keep in order. A- the vacuum was very likely to fall after a long exposure it was neces- sary to have two tubes if difficult pictures were to be made in rapid suc- ce--i< in. The "I'l/ltt >. A portion of the current will leap aero-- thi- -pare if the re-i-taiice in the tube ri-es. and in this way tra- u'ill lie liberated and the vacuum reduced. Acting a- an automatic governor, i hi- will prevent the vacuum from ri-ing above the level de- termined by the ilistaiice at which the wire i- placed. For radiography - better not to allow the regulator to act automatically. A -mall pleiluct of cotton moistened with water i- employed in the regulator of M tube recently constructed by l)ean. of London, and Ber- lemot. of 1'ari- V\<^. }^H . The regulator i- a separate portion of the /-ray tube with which M communication is established by turning T1IK .T-KAY 763 a stop-cock. Watery vapor from a \vct sponge in the small prolongation then enters the main hull) and lowers the decree of vacuum. Water-cooled tube* have been made by Gundclach, Miiller, and others in ( lennany, by Machlett, of \e\v York, and by Friedlander. of (Jermanv and Chica.no. In them there is a water-vessel (Fin;. 4S7 ' designed more or less perfectly to prevent the anticathode from becom- ing too hot. In the original Friedlander water-cooled tube the water surrounds the heavy copper stem of the anticathode, but the heat ther tubes are made in which the reduction of vacuum is produced by heating a prolongation containing potash or by passing a spark through it. In Thompson's automatic regulating tube this spark passes to the \vire which leads into the prolongation containing the potash whenever the vacuum reaches a certain degree of resistance, as deter- mined by the distance at which the wire is placed. The VnH-Olun tuht. has the secondary anode in a bulbous expansion if the positive prolongation of the tube. It i.- made \vith or without a .-emulator and the latter may be set to act automatically. It is also made \vith different weights of anticathode and is in every way a lirst- ':;i~- t ube. The l,nrin rnnnitn tuhi has the spark-.irap lending to the regulator en- \<>" >\ in Lard rubber to conceal the spark and reduce the noise, and it K- -< to :t''t automatically at anv decree of vacuum. i in - are made with a valve arrangement by which air may be ' vacuum 1< i\verei 1. i I Vied lander) a re made with an adjust able focus operated itn !), means ot a horseshoe magnet. A heavy cur- : verv small spot will fuse the platinum, while tins : lie i'< icus were less sharp. THE X-KAY 7<>r> structed on the same principles, but, as will be seen from the illustration, on a little different lines from the retaliating tubes of Friedlander and Miiller. Tubes made with an automatic regulator, as patented by Queen A: Company, may be run continuously for a long time, providing tliut the tube has a tendency either not to change in vacuum or to change slowly toward a higher decree of vacuum with the strength of current, that is employed. The regulator is set at such a point that a spark will leap across to it if the resistance of the tube increases in consequence ot the change to a higher decree of vacuum. The spark causes a generation ot gas in the tube and lowers the vacuum to the proper decree. Then- is a certain loss of radiance during the action of the automatic regulator. This must be taken into account in estimating the exposure. Five seconds is the proper time for certain pictures, but this would not be with interior filter. An abandoned model. long enough if a powerful spark were leaping across to the automatic regulator all that time. Helium (las in x-Raij Tubes. The mineral cleveite if purified over calcium and carefully dried gives out helium gas when heated. The purest channel rays or positively charged particle* are obtained in a Crookes' tube containing practically pure helium gas. Snook has patented an x-ray tube in which the regulator consists of a portion of cleveite which, when heated by passing a spark through it, liberates helium and so lowers the degree of vacuum. The claim is made that such an .r-ray tube possesses the property of giving out rays of a higher degree of penetration with the same medium resistance and other electric constants than tubes which contain other gases. The author has not been able to note very much difference, but the tube is an excellent one. A" -re/// tubes with on interior filter^ are provided with an arrange- ment for arresting the cathode, soft .r-ray. and secondary rays. It allows the exit of only the direct x-rays which radiate from the point of impact of the cathode stream upon the anticathode i Fig. 4Ss>. 1 J. Koscntluil, I'hvs. Zt'it., No. 1-', 1900. 7t)() MEDICAL ELECTRICITY AND RONTGEN KAYS Secondary rays, however, arise from the glass wall of the tube between the points marked .r and .r. This model has been abandoned. A -ray tubes have been made by Yillard in 1MI7. and Herlemont in J'.H>7. 1 in which an acc< xxori/ electrode of aluminum or magnesium is used to reirulate the deirree of vacuum. The vacuum is lowered by connecting the accessory electrode with the anticathode. It is raised by connecting the accessory elect rode with the cathode and using a weak "urrent. Yillard abandoned the idea because the absorption or liberation of molecules of gas was not abundant enough for practical purposes. High-frequency ,r-Ray Tubes. The tube referred to may not be entirely original with Machlett A: Son of New York, but they have made it so that it gives very good results. The new feature is the construction of the accessory anode in the form of an aluminum concave mirror like the cathode, but not quite so large. Cathode rays arising from this accessory anode are focused into a funnel upon the back of the anti- cathode which prevents the.r-rays produced by inverse discharge from reach in ir the field to be radiographed. The accessory anode may be used as the only positive terminal of the tube with the expectation that most of the. r-ray from inverse discharge will be suppressed. This arrange- ment makes the tube work excellently with a direct current induction- coil which is giving a irreat deal of inverse discharge and also with a Te-la or high-frequency transformer which gives practically an alternat- ing secondary current. The tube so connected may he used with a ('aid- well interrupter upon the alternating electric-light circuit. The tube has no valve effect tending to suppress inverse currents. The author's u-e of this tube has been with a 12-inch induction-coil, AYehnelt interrup- ter. 1 ID-volt direct cu'/renl. Is amperes primary current . and with such a decree of vacuum that the secondary current is s milliamperes. Both the accessory anode and the anticathode are connected with the posi- tive wire from the induction-coil. The exposure for a radiograph of a hand or of the teeth at a distance of 1< inches from the anticathode to The plate ;.- five seconds or less; and tor the anteropo.-tenor radiograph of the frontal sinus at a distance of 2"> inches the exposure is thirty seconds. The latter exposure is correct tor the abdomen or hip. but is somewhat Too long for the chest. \Yith the tube in this condition we find that the fir-i fifteen seconds are characterized by the presence of a -teady apple-green fluorescence and a sharp dividing line m the tube. After the first fifteen -eiice ol an inverse o.-es it - .-harp dividing verv effect i ve j'-rav is charge would produce a very the radiograph if a diaphragm and cylinder wer or two and in required it will the current at the end ot tnteen seconds and inder of the exposure later. The author does not irt to the varioii- devices u.-ed to .-uppress the in- as -park-gaps and ventnl tube-. t ube i- of t he type of 1 he i- a heavy piece of copper shaped c la Sorif'tr Frun<;:i l -< inches and a current of 11 amperes with a Cald\vell inter- rupter is turned on until sparks cease to pass. Then a change is made to the \\ehnelt interrupter with a current of 1") amperes until sparking ceases, and finally, to the \\ ehnelt interrupter with Is amperes of prim- ary current. The whole process of regulation takes half a minute or less and the picture is made as soon as this adjustment is finished. It must not be imagined, however, that this or any other type of tube may lie expected always to be in a condition to give the best pos- sible results as above described. Such a tube as we are describing may be found to produce these results when it is first purchased, and if it is used only for radiograph}'; and only with the specified strength of current and length of exposure it may remain in this condition for a great length of time. Another tube of the same type may prove dis- appointing at first and may gradually work into a desirable condition, while 1 others may require to be pumped out, exhausted to different degrees of vacuum a number of times before perfection is obtained. It is no exaggeration to say that every x-ray tube of every type in the author's possession has been pumped out several times. A tube 1 which is absolutely perfect and which has not been abused will eventually cease to work properly because the vacuum regulator becomes exhausted. A new regulator must then be introduced and as this involves opening the tube the latter must, of course, be reexhausted. The same tube- maker being patronized right along, he. of course, knows to what degree of vacuum the exhaustion should be carried to fit the tube for the opera- tor's apparatus and methods. Tubes with the same type of anticathode as this Machlett hi.irh- t reque.ncy tube 1 are made by a number of other manufact urers in America and Europe, and generally give excellent results with quite heavy currents and short exposures. The Renifar Self-rectifying x-Ray Tube. By surrounding the metal stem of the anticathode with glass, somewhat in the way European manufacturers have long been in the habit of doing, an effort is made to suppress inverse discharge. A test was made by the author with the Renifar .r-ray tube in- tended to be self-rectifying. In addition to the appearance of the .r-ray tube and the reading of the milliamperemeter which showed the direc- tion and strength of the prevailing current, an oscilloscope in series was a No observed. Xo spark-gap or ventril tube was used. AVith an ordinary r-ray coil, with the correct polarity connected with this tube, there \va< no inverse current. But connected with the wrong polarity the current pacing from the positive terminal of the coil to the negative terminal of the .r-ray tube was not prevented from passing through the tube. For practical purposes the tube was self-rectifying. A similar result was obtained with the author's direct high-tension iienerator. And the manufacturers report that the current from a step- up transformer without a high-tension rectifier will pass through this tube in one direction only. It is hoped that this or other self-rectifying .r-rav tube- may afford us the advantage of an .r-ray generator without moving parts. The Hydrogen x-Ray Tube. The gas in the tube is hydrogen. ,t),S MKDICAI. ELECTRICITY AM) RONTGEN HAYS There is a sealed-, tt'f accessory bulb surrounding an osmo-regulator and containing a sufficient quantity of hydrogen for a great many regula- tions, lowering the vacuum. Another osmo-regulator outside the hy- drogen bulb with a cuff of platinum raises the vacuum by withdrawing hydrogen. Hither regulator is heated by the high-tension current when the necessary connections are made. The anticathode is a block of copper with a tungsten button. MAC ALASTE R -WIGGIN CO. Fi<:. -ISO. The hydrogen j-ray tube. (Macalastor- \Viggin Co.) The commendable features of the hydrogen tube are not, however, a panacea for gas-filled tube difficulties. These are the inconvenience or possible difficulty of regulating the degree of vacuum back and forth for different kinds of work and a temporary untitness for use when overheated. Both of these drawbacks are present to a very much ureater extent in any gas-filled tube than in the Coolidge tube. The NitroKen x-Ray Tube. The residual nas is nitron-en and this i- al-o liberated tn>m the material.- in the regulator when the vacuum i- to be lowered. I'.xperiment - by A. Mutscheller 1 -how that nitron'en shows the I'':'-' tendency to combine with the electrode metals most commonly 'Principle- fr, r the ("-e i if Rniituen-rMV Tubes, \ Mut-i-heller .\e\v York 11)17, p. l_> THE X-RAY 709 used; and it is selected therefore as the residual gas for the XitroKen tube. This shows a dense yellowish-green fluorescence. Its regu- lator contains nitrites of thorium, aluminum, and barium, which when heated liberate nitrogen; and they tenaciously hold other gases, such as oxygen and hydrogen. In regulating, if the vacuum becomes a little lower than normal the current passes through the vacuum to a wire leading to the anode and no longer through the regulating substance. Allow the tube to cool fifteen minutes and then pass a moderate cur- rent, such as 20 ma., for one-tenth second Hashes frequently repeated through it to raise vacuum to normal; or 3 to ma. for longer times. \'act(ittn Regulator. The materials in common use (asbestos, char- coal, caustic alkalis, soda, lime, asbestos-wool) when heated by a high- tension current as a rule yield water vapor, carbon dioxid, or hydrogen. All these tend to render the vacuum unstable as compared with pure nitrogen. There is danger of overregulation and occasional require- ment of a new regulator. The NitroKen tube regulator is claimed to be practically inexhaust- ible, but an inconvenience is that the vacuum always becomes too high after exposure and requires reduction when used again. The advantages Fig. 491. The Tousey single-focus radiographie x-ray tube. claimed are great constancy of vacuum during prolonged or heavy ex- posures and that no seasoning is required. Texts of the NitroKen Tube by A. Mutscheller, Six-inch spark 04,000 volts, 5 ma. for eight minutes; target red hot, but vacuum un- changed. Four-inch back-up, 40 ma. exposure of ten seconds, in steps of one second each; twenty seconds, pause; another exposure of ten seconds, produced no change in vacuum. Reduced as far as possible and also passing a current of 30 ma. through the regulator for ten seconds; then showed a back-up of 2^ inches with a current of 40 ma. After standing fifteen minutes and receiving occasionally a few flashes of 20 ma. it was 4-inch back-up and 40 ma., and fifteen minutes later tin- vacuum was so high as to have 1 required reduction for use. A few tubes have been particularly described, but this is not intended as an implication that others not alluded to are inferior. Sinclair Tousey's Tube for Radiography. 77? r Xinr a static machine or a direct current step-tip rotary transformer, or an allernai my 1 current step-up transformer with some kind of a rectifier. 77" Tnuniif l>'ii, i, -til l^in/i/i/inijifiir 1'nlx ( Fi A'-ray Tubes Without an Anticathode. Kontgen's original .r-ray tube-; were made without an unt icat hode. 'I lie x-rays arose from the impact nf the cathode rays upon the glass wall of the tube. 'There were two objections to thi- for radiography: the x-ray radiated from many different points of ;i larire surface and hence the shadows were very vairue as compart-d with those produced by rays radiating from a sinirle point : and the irlass wall of the tube became overheated if a heavy current \viis M-' to obtain tablets of platinixed chroiniuin which are hard and resistant enough to take the place of cast metal. The same method ol agglutiiiixation of metallic powders enables us to get anti- rathodic mirrors formed by conglomerates, the surface and the body of which are respectively constituted by substances we know to be desirable as anticathodie surfaces or as supports for ant icat hodic mirrors. (iuillo/ has found that metallic hydrids. such as barium or cal- cium hydrid. have no appreciable ten-ion of dissociation in the cathodic vacuum, and that an electric spark or ellluve sent between two little electrodes made of these hydrids liberate- hydrogen. These properties allow us to regenerate the gas necessary for the good working of a tube which has become too hard. T<. that effect, part of the current is diverted to two small accessory electrode:- contained in the tube and carrying (either one or both.< calcium hydrid on one of their extremities. These electrodes are prepared by keeping calcium hydrid Fit:. 49.s. Tu cylinders in hydrogen gas at oDO" ('.. but not long enough to have 1 he met a I attacked to t he center; if the time of exposure were too long t he elect rode would be friable. This regenerator is belter than that formerly used by Guilloz, which was formed bv thin sheets between which a spark was sent. The cal- cium hydrid electrodes have an unlimited regenerative power. Th'- tube- harden m the course of their natural use. They may b'-come too ~otl n too si rong a current ha> been used or t oo manv sparks are - ' nto the regenei'ator. In the latter case a good vacuum may be re-tored !iv -ending a \\"eak current t h rough t he t ube for a long time. I oi a toot h piclure or one of a hand any t ube will be suitable which '.'."ill give a good brilliant fluorescence in the fluoroscope and whose ,:M can be adjusted for the work in hand, but for the thicker port i , e body one of the heavy target tube.- i.- alwavs to be . lor the most difficult work the operator, of cour.-e, will u.-e rhf type o] tube which he lia- foiij.d will .-land a heavy current ,'."!' I I0l|' .' '..'', c|i;jl)1 ordinarily act as a cathode. uriotis, however, that the author has noted an increased re- -hown by a higher voltage as such a tube has become hot enough i<>r the anticathode to be incandescent. The resistance of the 1 ube is liable to drop -uddenly under very heavy current, but will return to the normal as soon a- the current is turned off. Experiment s by ( 'ole' show that with a current of :>() ma. and a resistance equal to that of a parallel irap of 5 inches, an expo ma., and two seconds for the hand. An experiment by ( 'ole shows that with a parallel gap, 7 : , inch, 10 to S ma., a total exposure of six minutes, with a screen of o mm. of alum- inum, there was at .">', inches from the anticathode a surface 1 effect of S II.. and at the further side of a piece of beefsteak, 2 inches thick, an effect of 4 II. The vacuum is practically absolute. The tube is Invited as hot as possible without softening the glass while completely enclosed in an oven for an hour or two. This liberates most of the air and other gases or vaporizable substances in the component parts of the tube. Then with the air-pump -till in operation and with the filament current and also the high-tension current turned on the anticathode is kept brilliantly incandescent for about an hour. The cathode is essentially a small coil of tungsten wire 1 which when traversed by a cunvnt of about 12 volts ;.nd something like 1 4 am- peres becomes incandescent anel liberates electrons. These are carried by a high-tension e-urre-nt as the' cathode 1 stream, whose impact upon the antie-athode produce's .r-rays. The- high-tension current cannot pass through the Coolidge tube 1 unless the 1 cathode- filament is in a state of incandescence. If the 1 filament is broken, or the low-tension current is not turned on. or the low-tension cire-uit is broken by a bad connection somewhere, then no voltage, however high, will cause' electricity to traverse the space of an inch or less between the- cathode 1 and the anti- cathode. A im-ater degree- of incandescence-, caused by gre-ater amperage of the filament current, lowers the resistance to passage 1 of the high- tension current anel produce 1 - all the- effects of lowering the- vacuum in a u'as-filled tube: vi/.. shorter parallel spark-gap, lesser voltage-, greater milliamperaue. lesser de-give of penetration as measured by Be'iietist -rale, greater contrast of light anel shadow in a radiograph or upon the fluorescent screen. This can be- instantly varied e-ven during an ex- pi t-ure of a few seconds. The ii/i/iciif/Kx/t in the standard Coolidge- tube i- a solid mass of tungsten which actively generates .r-rays of a useful spectrum and which i- very resistant to heat, with a melting-point of MMOO F. The Radiator Type ( 'nolidu'e- tube's have an anticathode consisting of a block ef ce>p- per with a tunu'sten button at the focus. The anticathode stem is -"lid and project- outside the- tube 1 . To this stem is attae-he-el a radiator fur the rapid di--ipation of heat in the air. ( >/,< ration- A current of 12 volts and about 1 amperes is sent through the filament from a -torau'e-bat tery or a transformer, anel cither of these mu-t ordinarily be in-ulated so that one wire may be connected with hiuh-tcn-ion circuit without danger of grounding. High-tension ale snows ad ive .r-ra< lia t ion. in l he standard 1 ul >e even 1 ! -pecial connection with the production of .r-rays. iated hemisphere -mme-is ab-ence of secondary the with the author's generator as originally constructed, there was one adjustment with which even the full power and the highest resistance would not exceed til) kv.. hut this would tiive an enormous milliam- peratie at that voltatie. And another adjustment made variations up to above- 100 kv. an easy matter. The 1 . S. Army portable outfit 1 lias a fixed ratio of tiansformation of the high-tension current and a fixed re- sistance in the filament current, so that the only variable factor is the re-istaiice in the primary of the high-tension generator. And for this apparatus all the opera. tor has to do for radiography is to adjust the last-named resistance so that \\ or ."> ma. will pass through the Coolidge tube, knowing that this \\-\\\ automatically produce a parallel spark of ."> inches. Ordinarily, however, the filament current is regulable. It is of the greatest assistance to have a table of adjustments for one's own apparatus. This can be supplied in part by the manufacturer, but parts must be worked out by the operator himself. The adjustment of the primary rheostat of the generator and of it- ratio of transformation control the amount of power applied to the .r-ray tube and the limits of its voltage. The factorial division of this power into quantity or milliamperage, and ten-ion or voltage or parallel spark-gap is regulated by the rheostat of the filament current. Thus, placing the handle of this rheostat in a certain position auto- matically sends a certain number of amperes through the cathode filament, causing the tube to have a resistance equal to that of a certain parallel spark-gap and to be capable of transmitting a certain number of millianiperes. The table should state that with each adjustment of the rheostat of the primary of the high-tension tienerator (within useful limits") and each number 'from r>.S to 4.:i by halves of ,',, of amperes of filament current, the voltage, parallel spark, and milliamperage will be so and so. To determine these factors for oneself 1akw, move the rheostat to li o'clock, \\hen we reach a power re either the voltage is too h'mh and the millianiperage too voltatie too low and the milliamperage too great, we begin inilate the amperatie of the filament current, and this, with or nit a -li^ht further chantie of the generator rheostat, will enable us cure exactly the hi^h-t elision current factors desired, \\ith the iwn tieneralor and a standard ( 'oolidge t ube, 7 o'clock generator > amperes filament current produce exact Iv 70. 000 volts tho power by moving the generator rheostat one hour mark, and find out by experiment what amperage of filament current corresponds to 70,000 volts and the numher of milliamperes which tlien flow through the Coolidge tube. Then gradually increase the filament current, noting for its different values the voltage and milliamperage produced. Do the same tiling at different hour marks up to the highest power that the manufacturer advises you to use. At the higher powers it will not be wi-e to reduce the voltage below GO, 000 because of the enormous milliamperage sent through the standard Coolidge tube and its conse- quent overheating;. The Radiator ('oolidge Tube will not stand more than 10 or HO ma., according to whether the focus spot is small or large. Also an excessive current might overheat the generator. The table should especially show the position of the generator, rheostat, and the filament amperage suited for deep and superficial radiotherapy: for fluoroscopy; for radiography of the teeth (with oo kv. and 80 maJ; for radiography of the. limbs, chest, and kidneys (with 55 kv. and 30 ma.") and 30 ma. with (if) kv. for gastro-intestinal radiography; and for frontal sinus radiography (with (if) kv. and 30 ma.). It is not sufficient to set the rheostat which controls the filament current at what is considered the proper position, but one should actually see by the meter that the proper amperage is flowing before turning on the high-tension current. From that time the amperage of the fila- ment current is disregarded and one's attention is fixed either upon the voltage or the milliamperage of the high-tension current, whichever meter is most conveniently placed for observation. Meanwhile one's hand is upon the rheostat of the filament current ready to adjust that to counteract changes in the high-tension current so as to maintain the latter practically constant. This regulation during the exposure is necessitated by the fact of changes in the resistance of the ('oolidge tube which would prevent uniformity of results if not counteracted. Some tubes will undergo such a rapid lowering of resistance im- mediately upon turning on a very strong high-tension current as to re- quire very great regulation instantly. If this were not done the picture would lie ruined and the tube and generator might be damaged by overheating. Such a Coolidge tube had better be used only for the lesser powers where its variations are les- rapid and there is more time to compensate for them by regulation of the filament current. Or the target may be incandescent to start with. S/)tirl;-i/ti/> and xphitrcniffcr with the ('oolidge tube. It is quite a useless performance to adjust the generator so a- to produce a certain parallel spark with the tube disconnected or its filament current turned off. But the value of the spintremeter is very great for standardizing one'- voltmeter with the tube in actual operation. The voltmeter on an .r-ray generator is generally graduated by the manufacturer by a system ot calculation and the graduation- may be quite far from riuht. A spark between two insulated polished metal spheres a certain size and with a certain atmospheric pres-ure furnishes a very exact mea-ure of voltage. And even the ordinary spintremeter i- very useful to mark on one's voltmeter graduations corresponding to various lentil hs of spark-ii'ap. But the Cooliduv tube can be adjusted more quickly and maintained more easily at a certain spark resistance by observing the voltmeter 7SO MKDH'AL KLKCTHK'ITY AM) RONTOKN HAYS than by fussing with the spark-gap itself. And one can leave the gap so far open that slight variations in resistance' will not cause the current to Hash across the gap before they can be corrected by regulation. A Coolidge tube -hould always have its filament current turned on before the high-tension current. Some tubes will show a very marked drop in resistance the moment that a powerful high-tension current is turned on, as described elsewhere'. This is a disadvantage which has been attributed to misuse of the tube, such as overheating. It certainly never u'ets better, and the author would advise testing a Coolidge tube with the strength of current that is to be used for one's heaviest regular work before making a purchase. For instance, an exposure 1 suitable for a trastro-intestinal radiograph and started with the' right factors -hould not result in a terrible drop in resistance 1 and voltage and a ruin- ous increase in milliamperage. The' change does not appear to be 1 due entirely to a reduction in the 1 electric resistance of the filament. And it occur- so suddenly on turning on the 1 high-tension current that it does not seem likely that it is due entirely to liberation of electrons by in- candescence of the anticathode. Most Coolidge' tubes require slight regulation during an exposure, but the change should not be' so great as that described above 1 . The disadvantage referred to is more apt to manifest itself in heavy radiographic work than in radiotherapy. The same tube may transmit a unifoim current of o ma. and 70 kv. for ten minutes with only the 1 slightest occasional regulation of the filament current, and that probably only at the commencement of the exposure. \\ith the standard type of Coolidge' tube the' marked change in resistance as the anticathode becomes incanelescent can be' rendered less disadvantageous by starting the 1 exposure with the tube already hot. The resistance remains quite uniform during even a prolonged period of anticathode incandescence provided that the current is not unduly strong. Making all adjustments to produce a f>-inch spark equivalent and Mil ma. the author sometimes introduces all the primary rheostat re-i-tance and so reduces the power to a minimum. Doing this without touching the filament rheostat changes the spark equivalent to a fraction of an inch and the milliamperage to about If). The 1 .r-ray ha- so ii'tle penetration that it would not produce a noticeable 1 effect upon the plate through a patient's body. And upon a film covered with thin aluminum five seconds' exposure produces the same effect as one- eiuhth second exposure with .Vinch spark and MO milliamperes. The I'lunn nl cum at may be furnished by a storage-battery such as two of the units having three cells each u-ed in gasoline automobiles, for i'j'nii ii>M and liuhthm. They yield 12 volts and are provided with a rheo-tat bv which the current -cut through the filament may be lated from about M 1 , to -I 1 , ampere-. A convenient arrangement ruinii con-ists in allowing the 1 10-volt electric current to pass i two liO-walt Ma/da lamps parallel with each other, but both - with the -toraiie-battery. This charging current of about 1 iid lie allowed to flow thnnmh the -toraue-bat tery in the t'i, ,n after each utilization for six or eight times as long as current ha- been turned on. The simplest way is to turn on rent in the interval- of a -eric- of exposures so as not end. The batterv must be THE a'-HAV 781 on a stand with insulating glass legs. The charging wires must bo about 10 inches from the battery whenever the high-tension current is on. Wai to A: Bartlett and other manufacturers make an outfit with which one can control the filament current and also the charging current from inside the .r-rav-proof booth. Water must be added occasionally to make up for evaporation. The life of a storage-battery is supposed to be about two years, but it will become worthless if left unused and with the acid in the cells for several months. It has seemed to the author that the very heav} current demanded for the Coolidge tube filament quickly, though tem- porarily, reduced the voltage of a storage-battery and necessitated an excessive regulation during the exposure. And after a few minutes' interval during which none of the controlling appliances has been changed, turning on the current will often produce a very different voltage from the one shown during the last part of a previous exposure. Further experience has shown the trouble to lie in the Coolidgo tube, not in the storage-battery. But these considerations were sufficient at the time to cause the author to discard the storage-battery and to install the following out- fit, which has the advantage of requiring no water, acid, recharging, or renewals : Motor generator and transformer for furnishing the filament cur- rent. Wo require a current of 12 volts and 3-> to -U amperes, and it is immaterial whether this is alternating or direct. The necessity that the wires leading to the filament should also transmit the high-tension current makes it ordinarily impossible to make immediate use of the electric-light current regulated by a simple rheostat. If the light cur- rent is direct, we use this to run a motor generator producing a low- tension alternating current, the strength of which is regulated by a rheostat. This current passes through the primary of a transformer which is so thoroughly insulated that over 100, 000 volts applied to the secondary will not occasion an escape of current to the ground or to the primary wires. It is not a transformer whose chief object is to product 1 a change of voltage, but especially to produce a current of electricity in a separate circuit completely insulated from the supply circuit. If the light current is alternating the motor generator is dis- pensed with, but the transformer for supplying the filament current is the same. In some modern experiments the negative pole of the high-tension generator has been grounded. The voltage becomes zero at the cathode of the Coolidge tube and twice as high as before at the anode. The negative terminal can be approached without receiving a shock and one has to keep twice as far away from the positive terminal. The latter fact may require special insulation in the generator. The principal object accomplished is doing away with the high-tension insulation in the filament circuit. This makes it possible to use a storage-battery with a simpler arrangement and especially to use the electric light current controlled by a simple rheostat instead of the complicated transformer with high-tension insulation. Dr. ( 'oolidge 1 thinks that the liberation of electrons by the immediate incandescence of the solid tungsten target accounts for the fact that the standard ('oolidge tube is not self-rectifying to anything like the 1 Personal communication, i M: MEDICAL KLEC'TIUC'ITY AM) RONTGEN HAYS same extent as the radiator tul>e, in which the anticathode never be- comes brilliantly incandescent. Very rarely, in fact, only once 1 in the author's experience, a Ooolidgc tube \vill cease to transmit high-tension current though the filament i> incandescent. The natural inference when this happens is that one has neglected to connect the high-tension wire \vith the positive ter- minal of the tube. This happens in the best regulated families. Having seen to this, the next step is to test the parallel spark-gap resistance measured at the actual terminals of the Coolidge tube, not at the gen- erator, as is ordinarily sufficient. It is desirable also to test the current for exciting a gas-filled .r-ray tube which will show by its fluorescence whether the proper strength and direction of current is being delivered. Fin. 4H9. Grounding a Coolidgc oxray tube. CJroi nd wire from B or D makes it pOS ssible to use the elect ric-light or storage-battery currei t without liigh-tcnsH n insulation r filament incandescence, (iround wire from A or ( would require higl -tension in- lation of storage-battery or transfornier for f iame it i icandescence. I using the ct ric-light current for a grounded Coolidgc .r-ra tub th ]iath of the fila cut circuit ould be from one terminal of the filament transfo mer o tl e ground connect in I) of the nerator and the .r-ray tube, to the filament tei ninal 15. through the fila cut to the uncut terminal ]'.. to the beginning of the rhco> at, throi irh t he variable sistance of i rheor-tat to the other terminal of the filament transform r which may be 'ither posi- These te.-ts having all indicated that the trouble was not in the generator or its connections will) the Coolidge tube, but with the tube itself, the manufacturers have been unable to suggest any remedy except remaking the tube. This means using the same metal parts in a new glass bull) at an expense of fifty dollars and producing a tube as good as new. ( 'ti<,l ;b- jection when an increased voltage* is use>el. The* e-opper and tungsten target should neve*r be Iwtter than a e-he*rry ml for fear of vaporizing the copper. \\ he*n this exvurs, a deposit of coppe'r cove*rs the whole inte*rior of the* glass bulb and the tube is use'le*ss. This type e>f tube* is inteneled for radiography alone*. It will not stanel the long-continueel brilliant incandescence e>f the* anticathode se> readily borne by the solid tungsten target in ele*e*p rontgenotherapy. It had better neve*r be incandescent. Radiography of various parts of the* head, trunk, ami extremities with the' radiator tube shows emlv slight diftVre'nces from those 1 maele 7S4 MKD1CAL KLK( THICITY AND RONTCKN RAYS with the standard Coolidge tube except that due to the ability to em- ploy the anticathode with a finer focus. This is doubtless due to the fact that in all these cases the secondary radiation from the patient's tissues is such a disturbing factor as to overshadow the differences in the radiation from the tube. The way in which the author expected the benefit to beappanient was in radiography of foreign bodies especially when combined with a means of arresting secondary rays arising in the tissues. The radiator tuUe is especially desirable for repeated radiographs within its capacity a- to current. It does not undergo the accumulation of heat which makes it necessary to allow a standard Coolidge tube to cool while it is alternated with others in making a series of radiographs. With the author's technic (see Exposure Table p. H'.Mi) the anticathode does not become incandescent, and any number of radiographs can be made at interval of one minute or more. There is no good reason for ever turning on the power on open circuit. With an .r-ray tube in the secondary circuit the effect varies according to the resistance of the tube. An electron discharge x-ray tube, such as the Coolidge tube, without incandescence of the electron discharge filament, behaves exactly like an open circuit, and so does a gas-filled tube with an excessively high degree of vacuum. Both varieties of x-ray tube in a condition to transmit the high-tension current have a similar ef'fectTentirely different from open circuit. With the same control of the primary current the, voltage of the secondary current is lowered and the milliamperage increased by increasing the conductivity of the x-ray tube. This is easily accomplished with the Coolidge tube by simply turning on more filament current and so in- creasing the incandescence of the filament, and with the gas-filled tube by lowering the vacuum. The simplest Coolidge tube and generator technic is available with a generator with only a single ratio of transformation and only one ad- justment of power and only one adjustment of the filament current in the Coolidge tube. The x-ray outfit recommended for dentists is of this character: and turning it on automatically produces x-rays of a qua lily and intensity corresponding with reasonable accuracy to 5-inch spark and 10 rnilliamperes. With the Coolidge tube apparatus usual in x-ray laboratories, one must know the spark-gap and milliamperage that are suitable for the case in hand: also what adjustment of transformer power and ratio of transformation (if there is more than one) will enable one to secure these factors by regulation of the filament current. This power and trail-formation adjustment should be determined with the Coolidge tube in operation and should always be the >ame. say, at the same buuon of the rheostat when the specified sp ;) rk and milliamperage are dc-in-d. The extemporaneous regulation should be exclusively of the filament current with one's eye UJHUI either the milliampere- metcr or the voltmeter, whichever is most conveniently located. If either of these i- correct the other automatically remains so, just as either end of a U-ver controls the other end. Man i //I/In/ inn of //// Coolitlijc TII!>I irith tin Author'* (',< aerator of C/in.-t/i nt ll/tjli-ti usiini Current, or irith ft Trnnfiformcr inches, 30 milliamperes. forty-five seconds. The entire anticathode became red hot and a considerable part of the copper in contact with the distal portion of the tungsten melted and dropped down upon the glass wall of the tube. At the moment this occurred there was a marked fall in the resistance of the tube indicated by an increase in milliamperage. The current was immediately turned oft'. The picture was perfect, showing calculi in both ureters. The tube had been securely clamped at both end.-. Although the lower part of the tube was splashed all over with copper the tube held together until it 50 780 MEDICAL ELECTRICITY AND RONTdEN HAYS hud been removed from the shield and then the hull) broke all to pieces. Evidently this exposure was a little too long for the tube to stand that strength of current without an interval for cooling. The unticathode of the radiator Coolidge tube should not be allowed to get hotter than a dull red heat. And Dr. ( 'oolidge advises a limit of fifteen seconds with this strength of current. The Author'* Precaution* in Case of Brealcai/e of the x-Raij Tube. An occurrence such as the above might have disastrous consequences if a part of the tube still charged with high-tension electricity were to fall upon the patient. And equally to be avoided is the possibility of the red hot anticathode dropping upon the patient. The tube is always enclosed in a tube shield of very thick lead glass and both the anodal and the cathodal prolongations are securely clamped. And covering the opening in the metal base of the tube-holder is a sheet of hard aluminum 1 mm. thick which would prevent anything from falling upon the patient. This aluminum acts also at all times as a filter to protect the patient from very soft x-rays and trom ultraviolet rays. Our Adrantaye Claimed for a Gax-fdled x-h'ai/ Tube. The focus point may be much smaller, and consequently it is possible to secure -lightly better definition. This is thought to be because a cathode stream made up of ions or charged atoms a million times the size of the electrons which form the cathode stream in the electron discharge lube does not penetrate the target to anywhere near the same extent. It should be noted, however, that a Coolidge tube excited by a direct constant high-tension current has the same properly. Inverse Discharge. Some tubes will show the effect of the inverse discharge by lacking the sharp division into a light and a dark hemi- -phere and by an irregularity in the ray produced. This inverse discharge is a current produced in the secondary coil by the ''make" in the primary current. Whenever a current begins to flow through the primary coil an induced current is generated in the secondary coil, ;md this is much weaker than the "break" current and in an oppo- -ite direction to it. This inverse discharge may not produce a noticeable effect if the vacuum in the tube, the nature of the interruptions, the strength of i he primary current and the self-inductance in the primary coil. ;ind the adjustment of the condenser are all harmonious. When it does Liive trouble, it may be cut out by a spark-gap across which tlic -econdurv current has to leap in pus.-mg ironi each pole ot the coil to the corresponding tip of the tube. These are properly called series spark-gups as distinguished from the parallel spark-gap directly between the two poles of the coil by the length of which the resistance and hence the degree of vacuum in the tube is measured. 'The name multiple spark-gups is applied to an arrangement by means of which thi- '-urn-tit mav be made to leap across from one to six or eight short gaps on its \vay to tin- tube. It is doubtful whether this has any advantage over the simpler single gap of adjustable distance; like the OM<- devised by the author. Resides cutting out the inverse discharge leap across a space of over ;m nidi the spark-gap has vent overheating the tube and enables us to use a vacuum is a little too low. It does not raise the oduces a ruv of a little more penetration corresponding uum, penal wav of cuttinu out the inverse discharge is, bv the IM.ATE ii PI.ATH 12 THE X-RAY 787 use of a ventril or valve tube. 'Phis is a vacuum tube of about the same size as an x-ray tube and has a regulator for maintaining the right degree of vacuum. Its positive and negative poles are differently shaped. One of the wires from the x-ray coil passes to one tip of the ventril tube; the current passes through the ventril tube and then through a wire passing from the other tip to the x-ray tube. This is quite a certain remedy for the inverse discharge, but is not an essential part of an x-ray equipment. Ventril or Valve Tubes. One pole of the Yillard ventril tube is made of a spiral of aluminum presenting a very large surface; for the origin of cathode rays. This pole acts readily as a cathode; and the ventril tube permits the passage of currents (lowing in such a direction that this pole is the negative one. The other pole is made of a small straight rod of metal almost completely ensheathed in glass and pre- senting a minimum surface for the origin of cathode rays. The tube will hardly transmit any currents which pass in such a direction that this becomes the negative pole of the tube. If ventril tubes are 1 used two of them should be provided and there are several different possible arrangements. One may be connected Co, I Fig. ")00. Single ventril tube connected in series with the cathode of the .r-ray tube. with either pole of the coil in such a way (Fig. 500 or Fig. 501) that the spiral of the ventril tube is connected either with the anode of the tube Coil 4- Fie;. .")()!. Single vontril tube connected in series with the anode of the .r-ray tube. or with the negative pole of the x-ray coil. Or a ventril tube may be interposed between each pole of the x-ray coil and the appropriate Fiji. ~>0'2. Ventril tubes between the poles of the coil and the tormina! Fig. .")():>. Ventril tube between the poles of the coil. Two may be used. pok 1 of the x-ray tube, as in Fig. ">02, taking car* 1 to have the correct poles of the two ventril tubes directed as specified above. 788 MKDICAL KLKCTHICITY AND HOXTdK.N HAY The third arrangement which should be provided for is to have one or t\vo veiitril tubes placed between the two poles of the x-ray coil, as in Kit:. -">()o. During the normal discharge of the coil practically no current passes through the ventril tube, but during the in verse discharge, when the polarity of the induction-coil is the reverse of that shown in the diagram, practically all the current pusses through the ventril tube. This occurs because the resistance of the ventril tube to the passage of a current in this direction is very much less than that of the .r-ray tube. This arrangement has been adopted by < I a iff e for his trans- former, which is actuated by an alternating current without an interrupter. The discharge is alternating, the impulses in OHM direction pass through the ven- t ril tube and t hose in the other and proper direction through the r-ray t ube. The Author's Arrangement of Spark-gaps and Ventril Tubes. Kach pole of the .r-ray coil ' Fi^r. .">(>."> ha- a short metal base upon which is seciireil a 'Jass roil about 1 inches long and at the end of this rod is ' ' ' "' ''''' '' a metal at tachment for the con- ducting cord leading to one pole metallic rod operated by an 1 -'i as in make a direct con- THE X-KAY 789 to the .r-ray tube In' bridging across the insulated space represented by the "lass rod. Or this metal rod may be turned back a little so that this space is not quite bridged over and the current has to leap across a spark-gap in passing from the coil to the tube. Or the metal rod may be turned back to the connection that leads to one of the ventril tubes. A ventril tube is held over each pole of the coil by a wooden bracket and its poles art- permanently connected, one with the metallic attachment at the distal extremity of the glass rod and the other with an insulated attachment which can be reached by the metal rod when it is turned in that direction. The only way that the current can reach this pole of the .r-ray tube when this connection is made is by passing through the ventril tube. The same arrangement is found at the other pole of the coil and each can be operated independently. The .r-ray lube may be connected directly with each pole of the coil, or through a spark- irap at either or both poles, or through one or both ventril tubes. It is also only the work of a moment to connect one or both of the ventril tubes between the two poles of the .r-ray coil. Yentril tubes become overheated and break if the current is forced through them in the wrong direction. Kven in the right direction they will not stand the heavy currents often used in radiography. The author Fin. 507. Current in the inverse direction resistance and longer spark equivalent finds them useful in radiotherapy arranged in series with the .r-ray tube it' the latter shows a tendency to inverse current, and arranged across between the poles of the .r-ray coil in radiography, but ninety-nine times out of a hundred they are not required. A ventril tube used in series with an .r-ray tube producing rays Xo. \ or o Henoist and consequently of proper condition for renal radiography should present a pale rose carmine color inside the alumi- num spiral, the inside wf the large part of the lube should present a rose-mauve color which becomes more pronounced toward the con- tracted part of the tube and changes to a clear rose color. At the anode there is a brilliant pink. In the prolongation into which the aluminum spiral extends there should be a faint red. not a green color, while the tube is in operation. Regulation of a. Ventril Tube. For most purposes a ventril tube should have a resistance in the proper direction equal to a spark-gap of about 1 or '2 millimeters (^-.- to -J-.- inch\ while in the reverse direction its resistance should be from 1 to 7 centimeters (\\ to 2 or 3 inches'). The degi'ee of vacuum is regulated by means of a spark regulator, as in Fi(H'>, or in other ventril tubes bv ln-ating the osmo-regulator. The Wehnelt Valve or Ventril Tube. This is a vacuum tube in which the cathode is composed of an infusible substance like carbon. '90 MEDICAL ELECTRICITY AND RONTGEN RAYS platinum, or tantalum covered with a metallic oxid. When such a cathode is red hot a difference of potential of IN or '_'() volts will send a current through the tube in one direction, but it takes ;>()() volts to send a current through in the other direction. It may be used to rectify an alternating current to be supplied to a \\ehnelt interrupter and the primary of an induction-coil. Such a valve tube may be used to rectify triphase currents. It requires three anodes connected with the three active wires and a single cathode connected with the neutral point. The current is then con- verted into a unidirectional pulsating one. The Ondoscope or Oscilloscope (Tig. 508 L- This is a glass tube about TJ inches long and about 1 ', inches in diameter, closed at both ends. IML'. .~>ON. Hi where electrodes are sealed in the glass and exhausted to the (ieissler degree ot vacuum. This is equal to :> or I millimeters of mercury or a pressure of -j MM! or T"iV ! iT77 f an atmosphere. The electrodes almost meet in the middle of the tube, coming to within r, 1 ^ inch of each other, where the\' may be separated by a vertical partition made of porcelain or mica, but in which there is a small central hole. The pan 11 ion is not necessary. Any voltage.- above .'>()() cause the tube to Imlit up around the end of one or both of the electrodes. The tube does not materially impede or affect the character of any of the high- tension currents which it is designed to studv. (See also page 73S. ) It forms part of the circuit which is to be tested as to the magnitude and direction of high-tension currents. Placed in series with an .r-rav IliJIII III tube ;i mass of violet light is seen to surround one electrode, while very little is around the other if there is little inverse discharge. Looking at (lie viol'-t liniit m a rapidlv revolving mirror it is seen to consist of -eparate flashes of li^ht : larger one.- in one direction, and alternate -mallei one.- iii the o'tlier direction. A photograph made with the ondo-c-)pc I-'IH. .")()' ij furni.-hes a chart which shows the nature and ..' ion of i he i lischarges. l.ediic and Morm' Use t he following method ,i; tnakiim these photographs: A lens i- placed near the ondoscope itli the openim: in a diaphragm. The room is absolutely md a photographic plate i- held at siidi a distance that the image i- Fnru. -pd upon it. Moving the plate laterally secures a series of linage- ni the successive flashes ot liirht. THE X-RAY 791 The ( 'akhvcll-Simon interrupter gives better tracings (Fig. 509) than the Wehnelt and most others. A very curious fact was brought out by varying the conditions in a mercury jet interrupter. The currents from the secondary coil become unidirectional when the duration of the period of closure is sufficiently small compared with the total time of a complete period. This fact seems to the author to be suggestive of the practicability of so timing a mechanic interrupter as to secure unidirectional sec- ondarv discharges from an .r-rav coil. The Author's Method of Ondoscopic Photography. An ordinary camera is placed upon a stand upon which it may be turned from side to side. It is focused upon the ondoscope, placed in a vertical position, before the current is turned on. Then the room is darkened, the camera is turned to one side, and its diaphragm is opened. The current is now turned on and the camera turned quickly around. Its diaphragm is closed as soon as it has completely passed the ondoscope. SECONDARY RAYS These are .r-rays, usually of moderate intensity, which arise from contact of the .r-rays or the cathode rays with any solid or liquid sub- stance. They radiate from all parts of the .r-ray tube and from everv portion of a solid or liquid substance traversed by the .r-rays. Secondary rays from the .r-ray tube may be called extra rays. The intensity of the secondary rays from different substances has been found by .1. J. Thomson 1 to be in proportion to their atomic weights, except in the case of nickel, which is the same as copper in this regard. Secondary Rays from an Aluminum Screen for Soft Rays. Secondary rays of slight penetration arise from an aluminum screen and are absorbed by the skin and have a tendency to create dermatitis. They may be arrested by covering the surface of the aluminum screen toward the patient with card-board or thick black paper. Derma Rays. --This is the name sometimes applied to secondary rays of slight penetration arising from the impact of the cathode parti- cles with the molecules of gas contained in an .r-ray tube or with the li'lass walls of the tube. They are rays of slight penetration and are similar to the secondary rays which are generated in the skin from the impact of the .r-rays. They expend all their energy upon the skin: 1 I'roc. Comb. Pliil Sot'., vol. \iv, 1007, p. lO'.t. 792 MEDICAL ELECTRICITY AND RONTGEN RAYS hence the name derma. These are some of the rays which are arrested by protective filters for soft rays. Experiments Upon Secondary Rays. An experiment may be made in which the photographic plate in its light-proof envelopes is held with its uncoated surface toward the .r-ray tube and with strips of platinum, lead, /me, and aluminum held at the film side of the plate. The plate is much more darkened in front of the platinum, lead, or /ino strips than elsewhere. It seems like a reflection, but is probably due to the development of secondary rays from the metal surfaces. Aluminum gives rise to hardly any such effect, but a thin sheet of aluminum between the platinum and the photographic plate does not prevent the effect of the secondary rays which arise from the platinum. u. .Ml. Experiment in halation, rilin ii] Fiu;s. ~>1 1 and .~>12, made by the author Dec.. !!() 1, show the results. A pair of shears were laid upon a photographic plate enclosed in black Mini orange envelopes. In the first the film side of the plate was up Miid in the other it was down. In Fig. 511 a certain part of the plate h;id a sheet of glass over it and wood under it. This part of the plate was lenst acted upon by the .r-ravs. The other two portions of 'In- plale were more acted upon. One had wood under and nothing but the paper envelopes fver. and the third part had sheet tin under and n< )' lnii'j but paper envelopes over. The plale with the film side d'i\vn Fin'. ."> \'2 -howed t he least effect from t he ./'-rays at a port ion with uder and nothing over. The next to the least effect was where there \va.~ l<-M\'2. Experiment in halation. Film down. Different substances over and under the plate outside of its light-proof envelopes. degree of opacity is almost directly proportional to the density of the different anticathodes. The theory is advanced that the x-rays arise partl\" in the deeper layers of the anticathode and undergo a certain filtration in emerging from it. so that the rays which radiate from it are largely those To which the particular metal is especially transparent. Lead transforms x-rays into more absorbable x-rays. Aluminum does not: hence a lead and an aluminum screen are more opaque than an aluminum and a lead one. Observations throw doubt upon this. This is true of polonium rays, but hardly demonstrable with radium. Diaphragms for the Suppression of Extra Rays. Rays originate from almost every part of the tube, and cause the image to be sliulnly 'Arch. Rfmtijyn Hay, Xo. M. April. I'.ms. iy* MEDICAL ELECTRICITY AND RONTGEN RAYS blurred as compared with an ideal condition limited entirely to the rays radiating from the focus-point on the anticathode. And it is possible by means of an ordinary diaphragm or series of diaphragms, or by means of Albers .Schoiiberg's compression cylinder and diaphragm cylinder, or by means of the present author's cellular screen, to practi- cally do away with the effect of these extra rays from the tube. An ordinary diaphragm may be made of .r-rn;/ metal or of lend or zlni- in any suitable 1 support and with an opening which may be varied according to the necessities of the case. It may have the somewhat complicated arrangement called the iris diaphragm, by means of which the opening is varied from the largest to the smallest by the synchronous motion of a do/en different sections and the opening always remains circular. Aii ordinary diaphragm which I find very satisfactory is that, furni-h'-d by the I-'rii dhmdn- shii I/I . This is a case which extends about, two-thirds around the ./'-ray t ube. and is made of frit lined with white lead, which i- opaque to the J"-ravs. There is an opening opposite the aniiralhode to allow the exit of rays emer^in.^ at a right angle to the loni: axis of the tube. The opening is at a distance of I 1 , inches from tin- anticathode and is '_' ', inches in diameter. It may be reduced in -i/e by the introduction of smaller diaphragms or of tubular prolonga- tions which can be introduced into the mouth, rectum, or vagina, and. of cour.-e, are especiullv intended for treatment. The ./'-ray tube is securely fastened in the Krirdlaiider shield and there is a stem to the shield by which i; may be secured in any desired position by the .r-ray stand. The Fneillandcr -hield affords all requisite protect ion for t he pat lent . THE X-RAY 795 but does not shield the operator from the continued effect of the second- ary rays arising from the uncovered part of the tube. The Ripperger shield is an opaque box weighing 60 pounds and large enough to completely surround the x-ray tube, and affords entire pro- tection except from rays emerging at an orifice which can be varied in size by the application of cylinders from 1 to 5 inches in diameter. It is suspended from a sort of gallows on wheels, so that it can be adjusted at any height above or below the patient and send the rays in any desired direction. Similar shield boxes have been used by Albers Schonberg and others, but the mounting of this one renders it the most convenient of all. Bergonie's 1 method of protecting the operator from the x-ray by having the tube close to the floor, so that the operator is above the plane of the Fig. .114. Compression cylinder and diaphragm. anticathode, is insufficient. It is true that very few x-rays radiate from the back of the anticathode, and that for a single exposure a person is amply protected if he is behind the plane of the anticathode and consequently is not exposed To the direct rays. There are. however, extra rays arising from the illuminated surface of the tube and also from other parts of it and from every part of the room. Constantly repeated exposure to these indirect rays will surely injure the operator sooner or later. .\llx-rx Si'hrinhcrcj's compression cylinder and diaphragm (Fig. 514' has a lube of brass lined with sheet lead either 4 or 5 inches in diameter and 1 inches long. The x-ray tube is held by clamps over a diaphragm of lead 11 millimeters thick at the upper extremitv of this tube and the lower end of the cylinder rests upon the surface of the body. There 1 ('. R. de 1'Acad. des Sciences. 1 10. 1 ,"><>(>. June ,">, 1 !)(),"). <9b MEDICAL ELECTRICITY AND RONTGEN RAYS are supports by which the apparatus is fastened to the table on which the patient lies, and clamps and levers by means of which the lower end of the cylinder may be pressed firmly against the body and in exactly the best direction. It serves to keep the part motionless, as; in the case of the elbow or ankle, and in addition to diminish the thick- ness of tissue in examination for renal calculi and other radiographs of the abdomen. The effect of the cylinder is to cut off the extra rays from a large part of the .r-ray tube, depending. I think, chiefly upon the position of the diaphragm at the upper end of the cylinder. The only direct rays that can reach the plate are those embraced by two lines passing from the focus to the opposite sides of the cylinder, but these direct rays would require no diaphragm or cylinder at all. The object is to cut off the indirect rays, and as regards them the diagram of Albers Schonberg is too optimistic. My own diagrams show. I think, that secondary rays reach every part of the plate em- braced by the widely radiating lines (Fig. ;">22. 7 and that the ima.u'e of a point p (Fig. .">22. c), consists of the point produced by the direct ray obscured more or less by a penumbra from extra rays embraced between the two dotted lines. The amount of penumbra about each -point of the image produced by the direct focus rays is the same, whether the diaphragm is supplemented by a cylinder or not. and is regulated by the size of the orifice in the diaphragm nearest the .r-ray tube. The two sizes recommended by Albers Schonberg for use with the two different sized cylinders are 1 inch and H inches in diameter. The diameter of the picture is 4 or 5 inches with the smaller diaphragm and 5 or (i inches with the larger. All these facts are recognized by Albers Schonberg. showing the impossibility of obtaining theoretic per- fection in the radiograph, but do not at all impair the value of the compression cylinder in cases where the lesion can be so definitely located that a picture ."> or (i inches in diameter is large enough. Tht f.V- of Loofah Sjiouuc witJi a Compression Diaphragm. This fibrous material can be made up into a hemisphere about (i inches in diameter and should be covered with linen. Placed over the kidney region and pressed upon by the compression cylinder it displaces some folds of the intestine and empties others of their contents. The pressure also renders the tissues more or less anemic, and in this way aids in the production of a deal 1 picture. This material is suggested by St rater. 1 I' may also be used with the author's board compressor. My own observations coincide with those of Albers Schonberg. that The diaphragm, with or without a cylinder. limit:- the focus rays strictly to those which are to form the .">- or (1-inch picture: and that in pictures through great thickness of tissue the secondary irradiation from the iis-ues i.- in this way very much less than if direct rays were shining i ill) all the neighboring parts of the body. The secondary rays m the ii'lass walls of the tube are probably all absorbed in passing 'hrouirh the tissues, so that his diagram may repre.-ent more nearly cor- : ly t han mine the condit ion which actually occur- m a pict ure 1 h rough 'he body. Mr diagrams -how what would be the result in taking a objects at a distance from the plate but without much of a ! issue. The chest wit h t he air-filled luniis would be such a case. A -mall diaphragm, made of non-conducting material, so that it may 1 Xcitschrii't. I'd).. I'.Mis. a -- THE X-RAY 797 be placed directly in contact with the glass wall of the x-ruy tube and so give a conparatively wide angle of illumination, is indispensable. The present author prefers his own board-compressor, with or without an air-filled rubber bag or a compression band(page 1051), for reducing the thickness of tissue and for immobilization of the part. It enables a full-sized picture to be made, and will be described in greater detail in discussing the radiography of renal calculi. Cole's observations 1 upon the secondary rays from an x-ray tube are important enough to be stated even if the present author does not entirely agree with them: 1. A new tube generally does not give good radiographs, no matter what type of apparatus is used to excite it. '2. This does not depend essentially on the degree of vacuum. 3. A well-made tube is easily brought to a stage where it will make a good picture if this seasoning is done gradually and carefully. 4. As it improves in radiographic quality its vacuum is better maintained. 5. After considerable service it is found difficult to lower the vacuum in the tube. 0. A stage is finally reached where one might suppose that the tube would soon be entirely unserviceable. 7. The tube is then in the best condition for radiography and will produce good pictures for a long time to come. 8. The dark color of the glass wall of the tube is, according to Cole, not due to a metallic deposit, but to a chemic change in the glass similar to that occurring in tubes containing radium. Edema of the Tissues as a Cause of Lack of Definition in Radi- ography. Radiographs of an injured elbow show the bones very much more clearly if they are taken before swelling sets in or after it has subsided. It would seem from the appearance of such a radiograph that the fluid must disperse the rays to a great extent, and not merely impede their progress along straight lines. Lichtenstein's experiment 2 in making a radiograph of an iron bar in a jar of water demonstrates this fact. The same author attributes the unsatisfactory results in radi- ography of the fetus in utero and in certain cases of calculi to the pres- ence of the liquor anmii in the first case 1 and of urine in the second. The following experiment by the author shows that secondary rays arise from various parts of the x-ray tube besides the direct rays from the antieathode. This is in spite of the supposed unidirectional char- acter of the discharges driven through the tube by the static machine: A silver dollar was held up near to an .r-ray tube actuated by a static machine, and looking through the fluoroscope a ten-cent piece, held in the shadow of the larger coin, could be seen perfectly well, unless it \vere held very close to the dollar. Enough .r-rays passed around the edges of f he silver dollar to illuminate the space, which would have been in absouite shadow if only the direct ray.- were present. The same result is found with an induct inn -coil and either a Wehnelt. Caldwell, or mechanic interrupter. It is found whether ventril tubes are used or not, and arranging them in series at one or both poles of the .r-ray tube or in shunt or parallel between the two poles does not prevent the same effect. 1 Arch, of the Rontgon Ray. No. f)"v 2 Munch Alcd. Woch., March f.. lOOti. p. 4444. MKDICAl. KLKCTKICITY AXD KOX'R.KX KAYS The author's radiating diaphragm prevents this while still giving a large field for radiography. An ordinary diaphragm or cylinder will prevent it if the opening is very small but this gives a much smaller field for radiography. That the effect is not due to rays passing through the silver dollar, and so making the penny visible, is shown by the fact that when a large sheet of the same metal is substituted for the silver dollar the penny ceases to be visible. A"-ray Filter or Screen for Soft Rays. The author attaches UTeat importance to the screen for protecting the .-kin from the less penetrating rays. It may consist of a single thickness of tin-foil of which 100 square inches weigh an ounce. A sheet of sole-leather is still better, and the author employs it for every radiographic and most therapeutic exposures. Experiments show that its absorb- ent power is equal to that of about 1 inch of flesh, and with a very soft tube practically all the rays are arrested, as they are mostly rays of little penetration. With a tube of medium vacuum, the rays of little penetration are practically all arrested, while those rays which will penetrate several inches of flesh all pass through. This screen covers the orifice in a Friedlander or Ripperger shield and enables the tube to be brought much closer to the surface of the body than would be safe without it. and arrests most of the extra rays arising from the tube. It is a necessity for cases in which the object of interest is in a thick portion of the body or head, but is very close to the plate. ( Ordinarily the .r-ray tube must be at such a distance from the plate that the image of the portion of the body nearest the tube is almost as dense as that of the object of interest, unless the latter is very close indeed to the plate. By means of this screen the anode is sometimes brought within o inches of the surface of the head or body, and the disproportion between the proximal and distal images becomes very great both in si/e and density. The case in which I find it most useful i- in radiography of a fracture of the skull or in mastoid disease. In either case the image of the part of the head nearest the plate is clearer and the amount of exposure to the r-ray s less than in the other way with the tube at a greater distance. Some other applications of this -creen will be described in discussing the radiography of special regions. The use of an aluminum screen for the purpose of protection from .r-rav burn has not obtained very great favor, but probably the proper thickness to secure equal absorption would be efficacious in the author's -creen for -oft rays. A piece of ordinary thick sole-leather, as suggested by ['fahler, serves admirably. There i- a further reason for the Use of the - in the fact that the various methods of rai U- to determine the quantity of soft rays sent o praclicalh only the amount of hard rays. Tl i tube occasionally producing a greater cutaneous reaction than \\ouid be expected even from a soft tube. Benoist's radiochromometer and the author's fluorometer show very plainly the amount of the ratini! ravs. but with a certain amount of these rays the amount of -- penetrating ravs will vary between very wide limits. This is notably true when a coil i- used, owiuir to varying conditions in the in'ir-rr ,: ' :. the ' ibe, and elsewhere; it i- not true to such an extent of the produced bv a -tatic machine. The -creen tor soft ravs THE Z-RAY 799 absorbs them, whether they are present in large or in small amounts, and acts as a shield against an undesirable effect upon the skin when it is desirable to bring the tube quite close to the surface, and the current must be a powerful one and the vacuum medium. There is one danger in the use of the x-ray to which attention may be called at this place. It has been noted that with the tube at a very considerable distance from the surface of the body, the x-ray appears to act upon the deep tissues equally with the superficial tissues, and in treating a cancer of the breast a periostitis of the ribs has been excited; so that with the tube at too great a distance the less penetrating rays reach the body with greatly diminished power, aside from their natural iaphragm uscil with the Ripperger shield in divergence; while the more penetrating 'rays have suffered little loss of power from traversing the air; and any desired effect produced upon the superficial tissues under these conditions will be accompanied by an almost equal and, perhaps, undesirable effect on the deeper tissues. This observation is of especial importance in radiotherapy, but must be borne in mind whenever the human body is subjected to the action ot the .r-ray for either examination or treatment. As far as possible the important particulars of every radiograph in this book are given. Neither in these nor in any other ever taken by the author, or under his direction, has there ever been any burn or even a redness of the skin, and never any evidence of any other undesirable ettect. Accidents of the kind do occur, however, and it seems to the 800 MEDICAL ELECTRICITY AND RONTGEN RAYS author that the hundreds of hours which he and others have spent in experiments with radiographs of inanimate objects, and the study of apparatus and technic, will afford something of a guide to others. The use of the author's screen for soft rays with a Friedlander or Ripperger shield enables one to take a picture safely, does away with extra rays from the tube, very much reduces the amount of secondary radiance originating in the tissues, and almost entirely prevents the access to the plate of secondary rays from the various parts of the room by suppressing the general diffusion from the x-ray tube. Pfahler's leather screen is usually employed. A -ray Stand, Protective Shield, Diaphragm, and Cylinders Used by the Author. This apparatus is made by Wappler, of New York, and the idea has been of gradual development. The tube is contained in a wooden box, coated on the inside with a sufficient number of layers of lead oxid to make it so opaque to the x-ray that no light can be seen in a fluoroscope held close to the box. Metal cylinders enter the box at the two ends and embrace the cathode and anode prolongations of the x-ray tube, anil are adjustable so as to bring the focal point of the anti- cathode directly in the axis of the diaphragm. Electric connection is made by springs enclosed in these metal cylinders pressing gently against the terminals of the x-ray tube, while the conducting cords from the x-ray coil are attached to the outer ends of the metal cylinders. A number of lead-glass windows permit of observation of the tube 1 while in opera- tion. The box measures about 2 feet long, 1 foot high, and 11 inches wide: there is an opening 4 inches in diameter in the bottom of the box, and to this may be fastened a diaphragm with cross wires for prelimi- nary use in placing the focus of the tube exactly in the axis of the dia- phragm. After this adjustment the cross-wire diaphragm may be removed, and either the simple 4-inch diaphragm may be used or a cylinder may be attached. The different cylinders are 7 inches long and are 1, 2, 3, 4, and o inches in diameter, respectively. They arc made of thick zinc, a metal almost as opaque to the x-ray as lead and more rigid than the latter. The box as above described was suggested by Dr. Ripperger. It weighs (>() pounds and is held by a stand which permits the box to be turned in any direction, to be raised or lowered, and moved forward or backward. The tube stand is of the model suggested by Birckner. It is of wood and rests on a broad, flat tripod; a horixontal arm holds the box, and can be moved back and forth by turning the knob of a rack and pinion. This is useful in adjusting the tube for radiotherapy, and especially for stereoradiography. The weight of the box and hori- zontal arm is counterbalanced by a weight, like a window-sash weight, which slides up and down in one of the hollow wooden columns of the stand. An improvement by the author allows of regulation of the degree of vacuum without opening the box. Two brass knobs, (i inches apart on the outside of the box, are connected by springs, one with the cathode ter- and the other with the regulating device of the x-ray tube. A e wire i- fastened to one knob, and may be bent so as to make a connection or a short or a long spark-gap between the regulating . The cut ire a ppa rat us weighs about 150 pounds, but it has rollers enable one u, push it over the floor. It costs about 8100. THE X-RAY THE AUTHOR'S CONTACT DIAPHRAGM 801 This is made of a double thickness of the opaque fabric used in x-ray protective aprons. It sufficiently covers the anterior hemisphere of the x-ray tube, and has a circular opening 3 inches in diameter. The si/e of this opening may be temporarily reduced to 2%, 2, l, or 1 inch by an iris diaphragm, or by different sized rings of the same material. The opaque material employed is a non-conductor of electricity and does not interfere with the operation of the x-ray tube or cause it to be punctured. The advantage to be derived is twofold: portability and increased area of illumination with equal definition. The diaphragm adds so little to the weight that the tube can be held in an ordinary tube stand. A diaphragm, D-D, of material which can be applied in contact with the wall of the x-ray tube will require a smaller opening for the same I'iLT. ">lii. Flexible contact diaphragm, forming protective shield with opening.- of various sizes. area of illumination upon the photographic plate than a diaphragm, D'-D'. which must be placed at a distance from the tube (Fig. .~>17<. The same illustration shows the smaller area of the tube from which vaga- bond rays may pass through a point A". There is consequently very little blurring of the image as compared with that which would occur with a diaphragm placed at a distance from the wall of the tube (Fig. ">lSi. where the opening in the diaphragm is large enough to give the same area of illumination. To secure equally good definition with a dia- phragm at a distance, it would be necessary to reduce the size of its opening Fig. ~>17) to that embraced at the level, /)'-//, between the dotted lines passing through X, and marking the limit of the opening in the contact diaphragm. The opening in the diaphragm, ///)' ' Figs. ")17 and .">lSi. may be the opening in a plane diaphragm or the proxi- mal opening in a conic or in a cylindric one. The best effect with the 802 MEDICAL ELECTRICITY AND RONTGEN RAYS latter, of course, is obtained when the proximal opening is reduced by a plane diaphragm so as to really secure the benefit of a conic shape. It seems from the foregoing that the diaphragm applied directly to the wall of the tube enables us to secure a wider field with equal definition. In actual practice a 3-inch diaphragm allows the radiograph to cover the whole of a 1 1 X 17-inch photographic plate, 'J2 inches from the anticathode, and shows both kidneys, ureters, the bladder, and pros- tate; and a 1-inch diaphragm embraces the entire pneumatic sinus area Fig. ~>17. T)-D. Tousry's contact dia- FIL'. .",1s. Large opening and greater i : .:-.-:L r ::: : smaller opening and much less amount of blurring with ordinary dia- Nurring than with ordinary diaphragm phragm giving same area of illumination //-//. as \\itli Tousry's contact diaphragm (.com- pare Fig. .-,17). nf the face. The- hitter may be excellently observed in the fluoroscope, if the operator cares to run the risk of injury, and a radiograph is easily made after centering the rays under actual observation. A 11-inch diaphragm gives sufficiently good definition, and as it takes in the entire face the fluoroscope need not be used in centering the ravs. A'-ray-proof Aprons, Gloves, and Spectacles. Sheet rubber containing baryta or lead oxid may be made as opaque as desired to the ./--ray. It may be cut into aprons or gloves to protect the operator. or into appropriate sixes and shapes to limit the field of exposure in a j iy. Spectacles of flint gla-s containing a large percentage of lead are a valuable protection for the operator's eyes in fiuoroseopic work. It must 1 ii remembered, also, thai even the reduced fraction of the radiation which will pass through the entire thickness oi the patient's body is in jurioii.- to the operator, who is often exposed to it. A sheet of lead glass covering the barium-plat inocyanid surface oi a fliioroscent screen enables one to see the image perfectly well while it protect.- the operator's face from the rays. A'-ray-proof Gloves. 1 Soak thick leather gloves in a saturated solution of bismuth chlond, ihen immerse them in cold running water fur an hour, drv them thoroughly, and repeal the process two or three times. An interstitial deposit of o.xychlorid of bismuth is formed. Material for A'-Ray-proof Garments. An improved material h; ; - :: .-' In en imported into this country. It consists of two sheets of strong cotton cloth between which is a thick layer of rubber containing : I Jr. Win. Mitchell. Arch, of Kontjr.-n Kay, April, I'.lOv THE X-KAY 803 a certain percentage of lead. It is much more durable than the mate- rials previously in use. The outer surfaces are sufficiently coated with the same rubber composition to be water-proof. Xafcti/ to the operator requires that he shall be in an rc-ray-proof cabinet covered on all sides and top with sheet lead or x-ray metal, an alloy of lead and tin which remains bright and does not rub off on hands or clothing. The metal should be /,-. or ^ inch, depending upon how near the .r-ray tube is going to be. The necessary windows are of very heavy lead glass transparent to light, but opaque to the .r-ray. All the meters and switches should be inside the cabinet. If no cabinet is practicable the operator should be behind a brick wall or a lead-covered partition extending across the entire height and width of the room. With these precautions he can dispense with .r-ray-proof clothing. The Fluoroscope. A fluoroseopic screen is usually a sheet of card-board coated on one side with barium-platinoeyanid, a chemical which becomes brightly fluorescent when exposed to the .r-ray. Tung- state of calcium can be used in the same way. The hitter gives a white and the former a greenish light. In a dark room the patient stands between the observer and the .r-ray tube, and the screen is held close to the patient with its chemically coated surface toward the observer. Wit h t he proper amount of radiance a pict ure is seen upon the fluorescent surface of the screen, which is really a shadow-picture, representing the different densities of the parts under observation. For most purposes it is more convenient to have the screen form the end of a dark box, which enables us to use the screen without darkening the room. The accessory apparatus and the details of technic are considered in the chapters on Radiography, Fluoroscopy, and Radiotherapy. A Home-made Calcium- tungstate Screen. The materials required are 1 ox. sodium chlorid, 1 ox. sodium tungstate, and t ox. calcium chlo- rid. Powder these together and put them in a crucible with a tin cover and set right in a fire with glowing coals heaped around it for two or three hours. The compound is converted into a clear liquid which crys- talli/es into a glass-like mass on cooling. Break this up into a coarse powder, put it in water, which will dissolve out the sodium chlorid. and fine crystals of calcium tungstate will settle to the bottom. Pour off the water, add more water, and decant. Do this several times until all taste of salt disappears. This part of the process takes twenty-four hours. Pour the sediment on a sheet of blotting-paper and dry in the sunlight. Coat a piece of tracing paper or linen cloth with flexible collodion oi' glue and sprinkle the fine, dry crystalline powder over it. Repeat the coating with collodion or glue and the sprinkling with calcium-tungstatc crystals two or three times. (The total cost of the materials including the crucible is only about 20 cents. 1 (Kolle, " A'- rays.") Intensifying Screens. If a photographic plate is enclosed in the same cassette, or entirely enclosed plate-holder, with a means of press- ing the two chemic surfaces close together, exposure to the .r-ray will produce a double effect. First, there will be the image produced upon the photographic plate by the .r-ray and. second, the image produced upon the plate by the bright fluorescent light which occurs on the screen. With the modern intensifying screen, the latter effect is three times as great and completely overshadows the direct .r-ray effect. There are some advantages connected with the tungstate of calcium 804 MEDICAL KLKCTKICITY AND H(")NT(iEN HAYS screen for intensifying, because it give's a whiter light than the barium platinocyanid screen, which is more generally used for fiuoroscopic examinations. Intensifying screens greatly shorten the time of exposure. The best ones, like those made by Dr. Threlkeld-Kdwards. of South Bethle- hem, IVnna., I. S., or made by Patterson reduce the time to one-third of the ordinary exposure. With the increase in speed there is some loss of details, as, for instance, in the 1 structure of the bones. As a consequence, it would not be desirable 1 to use an intensifying screen for making a radio- graph of the hand. Even with a weak, portable x-ray outfit, it is practi- cable to obtain a direct radiograph of the hand without an excessive exposure. It is a different matter, however, when the thigh or body of a large person must be radiographed with a portable outfit, and also when a number of radiographs must be made through the body, as for an ex- amination of the shape and position of the stomach and intestines, after a bismuth meal or enema, even with the most powerful apparatus. In these cases safety to the patient and convenience 1 and economy of wear and tear upon apparatus, and the desirability of snapshots of moving parts, e-dl for the 1 employment of an intensifying screen. A good intensi- fying screen has become an essential part of the- equipment of a Rontgen- ray laboratory. The best screens are' exceedingly fine 1 grained, and show very little of the structure eif the screen upon the 1 photographic plate if the ex- posure and development have been right. 7'iLTaphs in stout subjects, and most pictures of small children, "he only reasons for not always using an intensifying; screen are act of -liidit loss of detail and also the presence of grain with a e screen, the matter of convenience, and the matter of lag. Bone . in general and lung radiographs show better details of structure are u-ually done without a screen unles- there are special reason-; to the contrary. ( onveniencc of manipulation i- sometimes in favor of the screen. Thi- i- mounted in a cassette, which i- the most conve- nient kind of a plat e-holder, and to a void t he etiect of i he screen we have a piece of bhick paper over the latter. Either with or without the effect of the screen the cassette- is very much more convenient than black and orange envelope-. Y\ith film.-, however, such convenient holder- ;ire available 'page MO that while t he cassel te i- indispensable for -creen work, it has no ureat advantage when the black paper must THI-: X-HAY 807 without an adjacent dark-room in which to change the plates or films it may he very much more convenient to have the latter in separate envelopes. A considerable number of screens would accomplish tin 1 purpose, but are not always available and are very heavy. The Latj of Intensifying Novr//*. This is the persistence of radiance capable of affecting a photographic plale after the .r-ray has been turned off. After making any radiograph in which part of the screen is ex- posed without the interposition of the patient that part is found to be brilliantly luminous if the cassette is immediately opened in the dark- room. And a complete silhouette of the part depicted may be seen upon the screen. This would suggest the possibility of the picture becoming stronger if the plate wore left in contact with the screen until the lumi- nosity had disappeared and the possibility of the plate being fogged as it is removed from the cassette, and also possibility of a new plate put in contact with the screen receiving an image which would blur the suc- ceeding picture. Intensifying screens vary in regard to lag. In an experiment by the author a lightly coated intensifying screen in a ca-^ette was exposed to .r-ray, o-inch spark, 30 ma. ten seconds at 23 inche<. A minute later the cassette was opened and an East men dupliti/ed .r-ray film was partly in direct contact with the screen and partly protected by a piece of black paper. After two minutes' con- tact the film was fully developed and showed no trace of exposure. In spite of the brilliant luminosity there was no lag, and another picture could have been made without waiting for the light to have faded out. In a similar experiment with another make of screen the film was fully blackened except for a transparent image where a lead letter had been laid over the cassette while the .r-ray had been turned on. This screen had very marked lay;, although its persistence of luminosity was no different from that of the other screen which had no demonstrable lag. Visible luminosity in the part which had been covered by the patient's body indicates overexposure. It is only in the part of the screen un- covered in the first picture but perhaps forming part of the image in the succeeding radiograph that lag would be apt to be a disturbing factor. A lagless screen may, of course, be used for several pictures in more rapid succession than one with marked lag. With the latter several screen- are necessary when pictures are to be made in rapid succession. The choice of the plate for screen work is important. One like the Imperial .r-ray plate, with a thin sensitized coating, gives better results for this purpose than the thicker coated Ilford .r-ray plates, which are so much better for direct radiography. In making the exposure the glass side of the plate should be toward the .r-ray tube and the sensiii/ed surface toward the intensifying screen. For the best detail the exposure should be such that the plate will show the proper density after fifteen to thirty minutes' development with the Threlkeld-Edwards developer. More commonly a stronger exposure i> given which requires only three or four minute's' development. An over-exposure causes the image to flash up so quickly that the plate is fully developed in about two minutes, and shows every grain of the intensifying screen. It is evidenced at once by the appearance of the intensifying screen when the plate is removed in the dark room. s ' MKDICAL KLK( THICITY AND H(")\T(iKN HAYS Hie portion of the screen covered by the thicker parts of the patient should not show a bright persistent fluorescence. Thri'lkcld-Edwards Developer for Screen Plates. Water (distilled) 4S ounces. Sodium sulphite ulry) 2 ounces. Hydroquinone "> drains. Kikonogen i drain. Potassium carbonate (dry) 4} ounces. Potassium broinid (25 per cent, solution) f> drams. (One dram equals 4.0 grammes, and 1 ounce equals '.^'2 grammes.) The loss of definition in consequence of the granular character of the fluorescent surface is not deceptive in any way, and a reduced copy of a picture made in this way does not show the granular appearance. Radiography of the chest is a case in which very short exposures are likely to be more useful than those of medium duration. Even here the discovery of commencing consolidation is better made without an intensifying screen, seeking the element of speed in a brilliant radiance and a sensitive plate, and having the patient hold his breath during the exposure. This, however, is also one' of the cases in which a fluoroscopic examination would have advantages over the radiograph except for its danger. The different factors have been considered at length because of the assistance this may afford to others. To learn the successful and safe use of the .r-ray one must try to profit by the hundreds of hours spent by others in study and experiment, and must also expend a similar amount of time, money, and labor in practical work with the apparatus. THE SENSITIVENESS OF THE FILM. PLATE. OR PAPER The dry plates sold by the various manufacturers of photographic supplies under the name of .r-ray plates have about the best degree of >ensit iveness and are often made with a double or triple coating. The latter gives density to the picture, adds .-lightly to the speed of the plate, but adds very greatly to the time and care required for develop- ment. For some reasons it seems best , under cert ain conditions, to use the most rapid regular daylight plates, of which the Cramer Crown plate may be mentioned as an example. The daylight plates are in use in l;iri:e numbers everywhere and hence may be more easily secured m a fre-h condition than the special .r-ray plates. The kodak film produce- ;tn excellent .r-rav picture, but according to mv own observa- tion-; i-' about one-third as rapid as the Cramer (Town plates. A -eric- df experiment- has been made by the author to determine the relative -peed of the .r-ray and gaslight. It was found that gaslight \v;t- m;iny time- more rapid than the .r-ray. The comparison was made between a o-foot gas-burner at a di-taiice of ."> feet and a heavy target Miiller tube with ;i resistance of 2', inches, 1 2-inch coil with large self- inductance: ('aldwell interrupter, ( .> amperes no rheostat resistance: .'Hi'l ( miner .r-ray plate in black and orange envelopes, 11 inches from il ode, ditterent part- exposed fifteen, thirtv, sixtv. and one hun- dred and twenty seconds. The portion of a similar plate which was exposed to ga-lighl for forty second- was as dense as that exposed to the .r-ray for three time- a- King. I'oth plate- were developed in exactly the -ame wav and for the ,-ame length of time. It will be THE X-RAY 809 soon that the photochemic offoot of the x-ray from a tubo giving a brilliant radiance is only ono-third as groat as that of a small gas-jot at five times the distance. Taking the relative distances into account, the difference in power is about 7-J to 1 in favor of the ga.slight. Sunlight, of course, is incomparably more effective than the x-ray, photograph- ically. The wonderful thing about the x-ray is not the amount of effect it has on a photographic plate, but that its effect is produced even after passage through great thicknesses of animal tissues and other opaque substances. The Lumiere Sigma plates and films are four times as rapid as the fastest made in America and are excellent for x-ray work. Sehleussner's x-ray plates arc also good, but not as fast. The sensitiveness of regular brornid paper is about one-fifth that of a regular plate. This makes it suitable only for the extremities and the teeth. To make a good picture of any portion of the trunk upon this paper would require a dangerously long exposure. Wo sometimes use one or more pieces of bromid paper exposed at the same time as the film or plate for pictures of the teeth, hands, or feet. It enables us to got an immediate picture, not so good as it would bo if we were to give it the longer exposure which the paper really requires, but which is useful as a proof. It shows whether the position has been a successful one or not. The bromid paper alone is splendid for cases in which an x-ray diagnosis, is required immediately, as for the removal of a foreign body or the treatment of an obscure injury. The picture may be devel- oped at once without a dark-room, but in a faint light, and is made upon the same identical piece of paper which is exposed to the x-ray. This exposure is a very great deal shorter than is required for a fluoro- seopio examination in a case of any difficulty and prevents the possibility of a burn, either of the patient or the physician, and it will frequently show a needle or splinter which cannot be detected by the fluoroseope. Inconsequence, perhaps, of an article of mine upon this method 1 its use has become generally known, and in several instances physicians have written me of its successful application in cases where the fluoroseope had tailed and where the necessary apparatus and tochnic for developing a plate were wanting. Ivdntgen paper is now made as sensitive as tho usual x-ray plate and suitable for all kinds of radiography. It is a bromid paper, but requires to be developed by ruby light. The loss sensitive photographic plates are entirely unsuitod to general radiography. An exposure which will produce a good picture on the right kind of plate will often not show a trace of structure upon one of the less sensitive plates. There are many different degrees of sensitiveness in the plates made by the same manufacturer. Some are intended for one purpose and some for another, but when it is considered that the x-ray is only about ono~soventy-fifth as rapid as a moderate gaslight, it will readily be seen that only plates of the highest sensitive- ness are suitable. To produce a good picture through any thick portion of the body upon one of the less sensitive plates would require a dan- gerous exposure to the x-rav. Halation in photography is supposed to be the result of a reflection of liiiht back from the further surface of the plate. Its effect becomes Medical .Journal. August S10 MEDICAL KLI-XTRICITY AND KOXTUKX RAYS apparent when a photograph is taken of a very brightly illuminated object \vitli sharp outlines. Such a picture might be taken with the camera pointed toward a window with small panes and with bright daylight outside. Instead of what we are accustomed to speak of as photographic sharpness, we would obtain a picture showing blurred outlines of the cross-bars separating the panes, as if the effect of the brilliant light of the panes had extended partly to the dark portion of the plate upon which the image of the cross-bars is impressed. Yariou- remedies have been tried to prevent this reflection, and what are known as non-halation plates are considered the best. In effect the.e are plate.- with a double thickness of film, so thai almost all the light i> arrested, and the resulting image is so dense that the slight reflection which may still be present does not show upon the picture. All the celluloid films are almost free from halation. Experiment ing as to halation the author has made radiographs of sharply defined metallic objects, such as coin.- and needle-, placed practically in contact with the plate and with, the ./'-ray falling in some cases vertically, and in others at various angles, up to the greatest angle ever required in practice. In the entire series of experiments there was no effect of the nature of halation produced. A lead marker in the middle of the image, for in- stance, at the umbilicus, shows perfectly clearly, while one near the edge of the image shows a blurred shadow. This is due not to halation, but to secondary rays from the tissues, more from one direction than another. The purpose of having the objects as near as possible to the plate is to eliminate the aberration which inevitably occurs in the image of an ob- ject at any distance from the plate and which has no relation at all to the special condition produced by a diffuse 1 reflection from the back of the plate. My experiments have led to the conclusion that halation is not a disturbing factor in radiography, and that celluloid films or double- or triple-coated plates are not required on this particular account except with an intensifying screen. ( 'elluloid films, coated on both sides with an especially sensitive emulsion, are made by some of the manufacturers, expecially in Kurope, for instantaneous radiography of the chest, and an 1 intended to be used between two intensifying screens. The Kastman dupliti/ed .r-ray film is coated on both sides with an emulsion which give- it the same speed as the Seed .r-ray plate. It can t>e u-ed without a -creen or with either one or two screens. ( >ne very great mlriin/d'jr nf jUni* is that they cannot be broken either by the weight of the patient or during previous or subsequent handling. //, j! i// i/niin'H/i/ i if ('< llnluiil /-'.'7///N. A factor which must be taken account i- the inflammability of films, which has led to such fatal ident^ in moving picture theatres. Stringent laws require the motion picture film- to be enclosed in fire-proof boxes when carried on trains or when in any building. One might -upjxise that the heavy r deposit on both -ides of a dupliti/ed film might prevent the cel- d from catching fire. Hut in an experiment by the author, October THE tf-KAY 81 1 wrapper is simply folded over the film, preventing the abrasion marks which would develop if the film were pushed into an envelope. And the cardboard prevents abrasion marks in placing the film under the part of the patient to be depicted. They will hold one or two films. This would not be suitable for use with an intensifying screen. The latter requires a cassette in which the film and the screen are pressed very firmly together. Artefact* l']xi the Film. Abrasion marks develop as black lines. Another artefact develops wherever the film has sort of crinkled in being handled. The idea can be shown by lifting a sheet of white paper with the thumb over and two finders under one side or corner. The paper may bend in such a way as to show a distinct crescent ic crease about \ inch from the thumb. Such a crease in a film develops into a mark which might be mistaken for a calculus if one were unfamiliar with its cause. Such an artefact is to be avoided by holding the film at two opposite corners to prevent crinkling. Relative Speed of Eastman Duplitized .r-Raij Film and Seed x-I\a>j J J le. This is in ad- dition to the less serious, hut none the less annoying, burning out of fuses. Assuming that one's apparatus is capable of producing prac- tically the greatest possible .r-radiance with a given strength of cur- rent, and that one knows how to get the best results from it, the fol- lowing would be a desirable schedule: With tin induction-coil: Hand or teeth ."> to 80 seconds. Klbo\v or foot 10 to .")() Shoulder, c-hest, or knee . . . . 1 ."> to 120 " IVlvi-;. head, vertebra-, renal calculi 40 to 200 The longer time mentioned under each heading will suffice to make a good radiograph with a good coil and technic. but with a moderate strength of current. The shorter time given requires a great deal more studv of the -ubject and an apparatus which will stand heavy currents. Still shorter exposures may be obtained, either by the sacrifice of quality in the radio- graph or increasing the size of the coil and the strength of the primary current, about 40 amperes being the limit of the latter. This presents -till greater technical difficulties and increases the danger of injury to the tube or coil. In considering radiography of the individual parts of the body examples are given which show fairly the time required under different conditions. Transformers have reduced the exposures. Witli a transformer: Hand or teeth ?, to 2 seconds. Klbow or foot 1 to 5 Shoulder, chest, or elbow l.\ to 7'. Pelvis, head, vertebra', renal calculi 4 to 20 An i nti nxifiii /ifi xcrccn reduces the above exposures to about one-t hird. The rays which produce an effect on a photographic plate are the ones whose influence upon living tissues mu.-t be taken into account. With too low a vacuum one might fail to get a radiograph through the lumbar region, even though the. /'-ray were turned on long and strong enough to produce a severe burn, and the same may be true of .r-radiance of the riaht quality but from too weak an apparatus. In either case the little photochemic energv which does reach the plate .'i so -lowly that before the exposure \vas complete a dangerous effect would have been produce* 1 upon the tissues of the patient. A famous tnedicolegal case was that of a patient of I'rof. lloffa. of Berlin. ::. which case an exposure of forty-five minutes was required for a radiograph of the hip-joint, and a burn resulted. The patient hail :<' vion-ly been exposed to the .r-rav l>v some other phvsiciaii. The '.;:- dismissed because the exposure \va- in conformity with the '"--' technic available at that time. Improvements m every part of ' ' r-ray equipment have so much reduced I he t ime of exposure as to h possible to take a irood picture of any part of the hodv with .' no risk of any .-oil to the patient. This means that the TIIK .T-HAY Sl!i of the same part at tho same session. This is true of the body, and for the teeth and hands several exposures may he made. The element of time alone will not secure a good picture. I have known a man with a good N-inch coil to give an exposure of six minutes for a kidney-stone and obtain no picture, and an exposure at another session for sixteen minutes and find nothing on the plate. This resulted in a severe burn of the abdomen. A sufficient time of exposure is absolutely necessary, but it must be combined \vith correct details throughout. Over- exposure is undesirable, but may be corrected to some extent during development, and besides, the finished plate may if necessarv be examined by a strong transmitted light, so that a plate which would be practically useless from the standpoint of the daylight photog- rapher may still prove very good for the diagnosis and record of the case. The safe amount of time during which a patient may be exposed to the x-ray is dependent upon the intensity of the z-radiance and slightly upon idiosyncrasy. At a distance of 9 inches from the anticathode to t he surface of t he body, and with a tube of medium vacuum and an intensity which permits the bones of the li and to be seen faintly, nine minutes would be the maximum safe exposure \vithoutany previous experience with the individual patient. Such an exposure might produce a good picture of an extremity or possibly of the chest, but absolutely nothing of the pelvis, and with such radiance an exposure even twice as long as would be safe would not result in a picture of the lumbar region. The other extreme would be an .r-radiance so powerful that a pelvic picture may be made in fifteen seconds or less. There is. theoretically, no danger to the patient, but practically it is only in the most expert hands that success is certain at the first attempt. The employment of any such powerful current is dangerous if the exposure is prolonged, or if the exposure has to be made repeatedly, and this, of course, would be the case in inexperienced hands. It is very much better To learn to take perfect pictures with a moderate length of exposure, and to consider 1") amperes with a 110-volt primary current as the very outside limit, until one may fairly claim to know the '.r-ray thoroughly from personal experience. The principal injury which may occur to the tube trom too strong a current in the effort to shorten the time of exposure is either a puncture of the glass wall of the tube or fusing the platinum coating on the anticathode. A secondary coil which burns out in consequence of too heavy a current is a total wreck and may do con- siderable damage to its surroundings. The thousands of feet of fine wire are insulated in a mass of wax. and when the wire fuses from an overcharge the wax melts and fairly explodes. Of course, every coil is made to stand a current of a certain strength and for a certain length of time and this limit should not be exceeded. An exposure of one hundred seconds with a primarv current of 1_ to !""> amperes may often be advantageously divided into three of about thirty seconds. Several exposures of fifteen seconds separated bv intervals to allow the tube to cool often give the best results. Very few tubes indeed will maintain the same degree of vacuum during one hundred seconds with a charge produced by a current of 12 to 15 ampere.-, and. of course, alter a marked change has taken place the balance of the exposure is worse than wasted. During this time the patient must repeatedly be cautioned to stay still and. of course, it is gomu' to be best to have the plate Hat upon a table with the part to be radiographed resting upon it. 814 MKDICAL KLKCTUICITY AND KoNTGKX KAYS Radiographs of the head or abdomen with a single uninterrupted exposure without injury to the tube may lie made with a heavy anti- cathode tube, such as the high-frequency tube described on p. 7(i(>, a 12-inch induction-coil, a primary current of IS :imperes. and an exposure of thirty seconds. This is the time required fora photographic plate, but it may be reduced to 1 hree or four seconds if a celluloid film between two intensifying screens is used. Rapid radiography is obtained with alternating or direct current transformers. Pelvic pictures in one or two seconds, thorax in one- quarter second (see p. 747; also Exposure Tables, pp. S ( ,MMH)2). ililnt'rt Sj/<<>/ f ] nrinus .i'-R(!]i AppordtKK mifl Tccfinic. If reg- ulated to a 4- or .Vinch spark, as the case may be. while the tube is in operation and if there is proved to be no inverse discharge the milli- amperage forms a reliable direct measure of the speed. For instance, as compared with the author's exposure table-, twice the milliamperes would requre only one-half the exposure: or one-third the milliamperes would require three times the number of seconds exposure. There is no change in the picture. \aryinir the spark equivalent without changing the milliamperage has such a great effect upon the speed that a h'-inch spark equivalent has twice the speed of a ">-inch and four tunes t he speed of a 4-inch spark. With the longer spark there i< much less contrast in the picture. Increasing the spark and reducing the milliamperage without changing the power and the ratio of transformation increases the speed and reduce< the contra-t. It makes the radiation more suitable for thick portions like the head, anteroposteriorly, and less suitable for thin portions, like the teeth, or for portions requiring great contrast, as in examining for renal calculus. These facts reu'ardinu' radiographic .r-ray exposures apply to both electron discharge tubes like the Coolidge tube and also to gas-filled tube-. And the more closely one conforms in the use of the latter to the -park and miliiampere factors which have been learned from the use of the ( 'onlidge tube, the better will the radiographs be and the less will be the weai 1 and tear upon the gas-filled .r-ray tube. Uiln'iri ,^/itt/i n] l)i ' n't n //I I'lutis //in! I- * I in* nx ('cnipnvcd in'Hi tin ,\,i!<.) is an example of a plate ruined in tills way. The ordinary plate-holders used by photographers are excellent and produce no deleterious effect upon the plates, which can be kept in them as long as desired. They afford no protection against the .r-ray, however, and, therefore, there is no advantage in their holding more than one plate unless it is desired to take two pictures at the same time. A simple and effective )>l(ttc-holnirau\. Dec. 1<>. UMM 816 MEDICAL KI.KCTHH ITY AND KOVHIKX KAYS orange envelopes, the whole may bo placed in a plate-holder made of wood with a shallow depression and a thin wooden cover. Two plates face to face in light-proof envelopes remain in good con- dition for a long t hue. Aluminum C/txxtttt* a* Plate-holders, These are made to hold a plate or film pressed into close contact with an intensifying screen and protected from light by a front of aluminum which is very transparent to .r-rays. If the screen is fastened in the cassette, as is very desirable, the effect of the screen may be prevented by covering the latter with a sheet of black paper. Cardboard carriers for films are made by the Kastman Kodak Com- pany. They prevent the abrasion marks which would come from pushing a film into and pulling it out of an envelope and from irregular pressure by the patient during the exposure. Stereoscopic Radiography.- A tunneled plate-holder is useful for stereoscopic radiography, in which case it is necessary to take successive pictures on two different plates which are placed in exactly the same; position and without any movement on the part of the patient. The .r-ray tube is shifted a few inches after the first exposure and the distance lhat it is moved corresponds with the thickness of the part and the distance of the tube from the plate. The result is two different pictures which may be optically fused into one picture by examining both original plates in \Yeigd's modification of the \\heatstone stereo- scope, or by examining reduced copies of both plates in the ordinary hand stereoscope with its prismatic lenses. Ordinarily in looking at anv object oi 1 group of objects, of course, each eye sees quite a different picture, but the brain combines the two impressions into one picture, which has the property of perspective. This enables us to recognize at a glance whether one part of the object is project ing toward or away from us. and this without any regard to the relative size of its image. Of course, skilful drawing will sometimes cause an image on a flat surface to appeal 1 to stand right out. Theoretically, the two pictures in stereoscopic photography or stereoscopic radiography should be taken from point- of view just as far apart as the pupils of th" two eyes, but practicallv it has been found desirable, both wilh the camera and with the .r-ray, to vary this distance in accordance with the subject of the picture. In other words, it is often necessary to exaggerate or diminish the stereoscopic effect in order to product' the best perspective. 'The following table, worked out bv Mane ami llibaut. 1 is a useful guide, but ;is lon.Li as the distance lhat the lube is shifted is recorded, the exact d 1st a lice nl<'.-ui\. .lulv l.~>, THE Z-KAY 817 This must ho modified in certain cases, for instance, where we wish to show the relative position of ihe vertebra 1 and a renal calculus or a bullet embedded near the spine. In these cases we would use the number corresponding to a much less thickness of tissue than if, for instance, we wished to show the anatomic relations of the chest. In general, the nearer the objects of chief interest are to the plate, the greater is the distance that the tube must be shifted between taking the first and the second radiograph. There is required a convenient means of removing the first plate and placing another in exactly the same position, or, according to Caldwell's suggestion, metallic portions of the plate-holder projecting over The edge of the plate and by their image indicating exactly corre- sponding parts of the two plates. The plates may be pushed into a slot and removed without any movement of patient or stereoscopic plato- holder. The tube-stand designed by Brickner, of Xew York, serves a very useful purpose in stereoscopic radiography. There is an upright hollow wooden shaft in which plays a counterbalance like a sash- weight of a window. The saxh-cord is attached to a carrier, which in this way may be raised or lowered, and remains in position without any fastening or unfastening. Through this carrier then 1 passes a hori- zontal arm which is also adjustable and self-retaining. At the (Mid of the horizontal arm is the tube-holder, adjustable in every direction and secured by heavy screws. There is a scale of inches upon the vertical shaft and upon the horizontal arm, and the tube can be moved a measured distance in either of these directions without fastening or unfastening anything. The motion is made by a rack and pinion effect of friction wheels. Rippcrger's modification of this stand includes a box large enough to enclose the .r-ray tube and of material that is opaque to the .r-ray. This is an element of safety for the operator. The same tube-stand or its modification is useful for most of the applications of the x-ray in diagnosis and treatment: It makes it very easy to place the tube in the exact position required; it is also sub- stantial enough in construction to carry a Friedlander shield; and the fact that there is very little metal about it makes the arrangement of the conducting cords an easy matter. With a stand made largely of metal, of course, the Conducting cords should not be allowed to touch any but the appointed part of the stand, as otherwise there would be a spark and more or less waste of power and damage to the cords. Whatever be the construction of the stand, the clamp should grasp the tube by its principal prolongation surrounding the cathode stem, and not by the little projection from the tube, which is made for the principal purpose ot connection with the air-pump when the tube is being exhausted. Care must always be taken to prevent the patient receiving a spark from the conducting cords or from the points of the tube. There is a disagreeable but not injurious shock received, which would be accompanied by a burn if for any reason the patient were unable to break the contact bv an instinctive or rellex movement. Contact with both wires at once would be productive ot a very serious shock. I'il/coi/'s Mirror N/r/rasro/x'. This is one of the simplest, least cumbrous, and best instruments for examining stereoscopic radio- graphs, prints, or negatives. The plates or prints are placed on two SIS MEDICAL KLECTKK'ITY AND RONTGEX KAY.s sheets of ground glass while the observer looks directly at the right-hand picture, and at the xinie time sees the reflection of the other picture in a small triangular mirror iFig. 520, M). This is made by Radiguet and Massiot. 1 Stcreoradioyrapfu/ Without former will do this if there are two circuits each made up of an .r-ray tube and a vntril tube. The .r-ray ut ies have opposite polarit ies. Ynhn f SttTdn'inlioi/rd/ilit/. Stereoscopic radiography is useful in depicting -abject- like renal calculi and fractures of the femur, but for the location of foreign bodies better re-nlts are obtained by the com- parison of two different radiographs taken at a very much wider angle. The Nature of the Material Back of the Plate. In using the ordinary black and orange envelopes a distinct effect is often produced on the plate whi"li r- analogous to a reflection trom l he surface upon which 'lie plate with ils envelopes rests. In reality this effect i> due " o -erondarv ra vs caused bv t iie impact ot t h<- ./'-ray upon t he material back o| the plate. The.-e secondary l'a\> fill the entire J'-l'aV room alld are difTu-'i-d in everv direction, and unless prevented bv something opa'jue to them an extraneous effect will be produced on the plate from two sources: 1'irst, bv secondary rays ari.-m^ trom the direct ./'--ray THE X-RAY 819 which has passed through the plate and encounters wood or metal or glass, etc., close behind tlie plate; and second, by secondary rays arising from the .r-ray reaching various parts of the room without having passed through the part to be depicted. Imagine a brilliant electric light out in the open air on a dark night and an opaque body like a thick paper-covered volume held so that the light shines vertically upon one cover; we should find that the lettering on the other cover was not lighted enough to be seen. Hut now take the same brilliant electric light into an ordinary room, and the diffused light from every part of the room will be so bright that the lettering on the shaded side of the volume can be read very well. An analogous condition is produced by the .r-ray, but the secondary rays are so much less powerful than the direct rays that they only become a disturbing factor when the direct rays are weakened by passage through thick tissues, and the effect of the secondary rays is increased by the length of exposure required. In taking a chest or a pelvic picture, if there is an irregular backing of wood and metal with, perhaps, an air space, the evidence of this will be found upon the plate, and I have been consulted about such pictures which had proved quite a puz/le to the radiographer. It is my own practice to use a backing of .r-ray metal, lead and tin, about 3 milli- meter thick, behind the plate but outside of its envelopes. This cuts off any influence coming from behind, and whatever secondary rays are generated upon its surface are in proportion to the amount of x-ray .s striking it j so that to a certain small extent it acts also to intensify the image on the plate. If only a part of the plate is protected by the ./'-ray metal backing, the part, which rests upon the uncovered wooden table is a very great deal darker than the other, and in some plates shows even the grain of the wood. It is evident that wood either has a much greater capacity for induced .r-radiance than lead, or that it is transparent to the secondary rays coining from various parts of t he room. Two plates may be placed on top of each other, both in separate black and orange envelopes, and a picture be made upon both at the same t ime, and sometimes the picture upon the lower plate is the better. The lower plate receives only about two-thirds as strong an impression from the direct .r-ray because the upper glass plate is not nearly as transparent to the x-ray as glass is to ordinary light. The lower plate, therefore, is not as dense as 1 he upper, but t he image on it is somel imes clearer because the upper plate often almost entirely cuts off the less penetrating secondary rays arising from the .r-ray tube. The ./-radiance excited in the thicker tissues, like the liver, is the chief source of indistinctness in radiographs through such pails of the body, and this indistinctness may be somewhat reduced by having the film surface of the plate down, or bv using two plates. My experiments with a thin metallic screen over the plate have not thus far resulted in improvement in the image produced. The use of a diaphragm or cylinder to cut off the secondary rays from the ./'-ray tube reduces this indistinctness very decidedly. A practical point to be observed is in connection with the perspira- tion which may be present upon the surface of the part in contact with the x-ray envelope. If this strikes through the envelope it will produce a chemic effect upon the film, resulting in a picture in which the print will be seen spotted with white dots. To prevent such an accident it is MJU MKDK AI. ELECTRICITY AM) Ko.VTe.KX KAYs, well to always have a piece of blotting-paper between the x-ray envelope and the part of the body resting upon it, unless two plates are used face to face in the same envelope. Marking the Plate for Identification. Lead or other metallic figures and letters may be placed upon the upper surface of the plate, outside of its envelopes, and at the same time that the radiograph is made an image of these is also impressed upon the plate, and is repro- duced in every print made from it. My own custom is to have my name and the serial number of the plate, and sometimes the word "right"' or "left." Such a word is necessary in every case in which two ,-ymmetric portions appear upon the same plate, like the two side- of the pelvis, or both shoulders, or both knee-, unless there is known to be some striking difference which will enable us to identify the two side.-. It is possible to be pretty sure that a certain side of the plate represents t he right side of the body if we make a practice of having the film-side of the plate uppermost, and have a record of the position of the patient, whether prone or supine. Hut this calculation would be based upon the assumption that the plate was correctly placed in the x-ray envelope, and when a person is to be operated upon for a stone in the kidney it is necessary that there should be no possibility of error as to which kidney it is that the x-ray picture shows the stone to be in. In the absence of any special metal letters any suitable object . like a key or a coin, may be laid upon the side of the [date upon which rests the riiiht side of the body. A written note to that effect should be made before the exposure is finished. If not made while the plate and the marker and the patient are all in the same relative positions, the iden- tification of the right and left sides of the patient in the picture again becomes a matter of memory and calculation. The letters and fig- ures I use are r-at from x-ray metal about \ millimeter thick. If the plan is film ide up, the letters and figures must be completely reversed when laid on top of the plate in order that they shall appear in their proper relation on the print: but if it accidentally happen- that they are 1 not put on in this reversed peisition, it may later be bv printing the picture with the ulass instead of the film-side ate in contact with the velo.x paper in the printing frame, it convenient to have all the letter- of the name pasted in a po.-it ion upon a card, and to have the -mule figures past eel upon i a rd slips, which fit m a sort ot pocket on t he name card, t oget her -lip on which i- pasted either "riuht" or "left " An x-ray a ' raiisparency : if you are looking t hrou:Ji from one direct ion re of two hands the hand with the wedding riim on it may be the left hand, and if you look through the plate in tin iirection that hand will appear to be the right one. In a e of the two hands taken upon a plate with the film-side up. the hand with the wcddinii rim: on it will appear to be the left hand: but i- down, as it usually is in the print, the picture will RADIOGRAPHY i n t in mteri K i.-it ion of t h 821 depicted between the x-ray tube and the sensiti/ed surface. The effect produced upon the plate is the same as that produced by light in ordinary photography, and the plate is subsequently developed by the same processes lhat are employed with daylight pictures. The back- ground of the picture on the plate is produced by the unimpeded action of the x-ray, the half-tones by the action of the ray but slightly dimin- ished by traversing the flesh, which in thin layers is generally as trans- parent to the x-ray as glass is to ordinary light; the bones and metallic substances, on the ot her hand, cast deep shadows, and on those port ions of the plate the photochemic effect is but slight. An ideal plate K one in which the images of the bones, and especially of metallic foreign bodies, are nearly transparent, but with fine detail showing the structure of the bones; and the background is dense, almost opaque. A " print. '' or the finished picture, of which as many as are desired may be copied on sensitized paper from such a plate, shows the bones black with excellent detail of structure, contrasting sharply with the half-tones of the flesh, and the outline of the latter is clearly defined upon the pure white background. Such a picture can be obtained by what I have called a "normal exposure," meaning by that term the equivalent of the conditions necessary for perfect ordinary photographs. With an ordinary photograph the amount of light and shade upon the object, and the amount of light admitted to the camera, and the length of time during which it is allowed to act upon the plate, are all very commonly under complete control. \Yith the .Rom gen ray. however, it is only exceptionally that it is possible or desirable to secure all the gradations between opaque density and almost perfect transparency. With the hand and foot a normal exposure can readily be obtained, but with the thickest portions of the body this is entirely impracticable. The plate is usually contained in an opaque black envelope, and outside of this there is one of orange paper, and thus enveloped it is as safe from ordinary light of moderate strength as a plate in a plate- holder or a film in a camera. These envelopes ordinarily present no impediment at all to the passage of the Rontgen ray and the plate must, therefore, not be kept in or even near the room in which the x-ray is turned on. except during the actual exposure for taking the radiograph. Such a plate in its envelopes may be placed upon a table, the hand or whatever part is to be radiographed is placed upon it. and the x-ray tube placed directly above this at a distance from the plate which bears a distinct relation to the si/.e of the plate and to the thickness of i lie part to be penet rat ed. The ./'-ray is turned on tor the proper length of time and the picture has been taken, it being only necessary then either to develop it one's self or give the plate to a professional photog- rapher for development. There are differences between the develop- ment required for most x-ray plates and that used by the ordinary photographer whose plates have all had approximately normal exposures. These special points are detailed in the chapter on the development of x-ray pict un-s. Some of the factors to be considered in making a radiograph are the of brass, lined with lead in order to be opaque to the .r-ray. and is about -1 inches in diameter TIIK .{'-KAY and about ."> inches long. 11 forms part of a complicated apparatus by means of which one open end of the cylinder may be pressed against the abdomen or any other part. It produces in all cases fixation, and in some places, like the abdomen, reduction in the thickness of the tissues l-i'_r. ~>2'2, A. Compression diaphragm. (Kelley-Koett Company.) to be penetrated by the .r-ray. At the other open end of the cylinder the .r-ray tube is held in position by another part of the apparatus. The pictures an 1 , of course, limited by the size of the cone of rays which passes through the cylinder. The extra rays are not all cut off by any Fi-"-, B. -Dotted lines arc sec- ondary rays which would pass t hroimli an ordinary diaphragm, hut which are arrested In the walls of the cylinder. when a cylinder and diaphrag manner of means. All those emanating from a part of the tube 4 inches in diameter are free to take part in the production of the picture. It is certainly an excellent device for cases in which a small picture is sufficient. and in which it is possible to so judge of the position of the object of MKDICAL ELKCTKH ITY AM) KOVlXiKX HAYS interest as to direct the cylinder accurately enough to include the object of interest in a picture only a little over 4 inches in diameter. Author'* liuit/nti nt/ Cdlnlar Diaphragm. In the first edition of this work the author's radiating cellular diaphragm was described. It has been found, however, that it was necessary to use the rluoro- scope to so accurately place the .r-ray tube so as to cast only linear shadows of the wall of the central funnel. This involved a dangerous exposure of the operator and caused the use of the apparatus to be given up, but now his improved apparatus makes it safe and desirable for use with a lias-tilled tube. It is not required with a ( 'oolidge tube. Author'.* .r-luii/ Tithi' irith Radiatnnj Diaphragm. An .r-ray tube invented by the author has permanently attached to it a radiating cellular diaphragm whose wall is of thin lead glass and casts a narrow linear shadow because it is part of a hollow cone whose apex would be at the focus point on the anticathode. The idea is useful only for a gas-filled tube where it prevents many of the secondary rays from the glass wall of tin 1 .r-ray tube reaching the plate: and it does this without reducing the size of the picture. The latter, however, does show a nar- row rin-; and the advantage of having the cone permanently attached to the .r-ray tube is the saving in time as compared with extempora- neously placing a radiating cellular diaphragm with the necessary ac- curacy. The .r-ray tube itself may be of ordinary glass, or all but the portion most useful for radiography or fluoroscopy may be of lead Author'* Radiating Diaphragm for Attachment to .r-rai/ Tube. A radiating cellular diaphragm invented by the author has the conical part of thin lead glass or some other material not of a nature to cause damage by being in close relation with the .r-ray tube and with metal- lic parts of the tube-stand. The conical part is permanently fastened to a part spheric portion of such a curvature as to fit accurately when simply bound in contact with an .r-ray tube of the size for which it is designed. And the conical part has such an angle and is so directed that its wall will then radiate from the focus point. The spheric part is of glass transparent to the .r-ray within and for a certain dis- tance outside the small end of the cone. There is an advantage in makintr the remainder of it opaque to the .r-ray as with lead glass. Thi- i- intended for use with a gas-filled tube for preventing a large part of the secondary .r-rays from the glass wall of the .r-ray tube ivai-hinii the plate, while not interfering with the direct rays from the focus point except for a narrow ring which should appear as a mere line upon t he plate. This i^ 1 letter because more easily placed in the proper position than the radial inii cellular diaphragm fastened to any part of the tube -tand. But it is not available with most tube stands. An .r-ray tube of the proper diameter for this diaphragm may be found not to have its focus exactly at the center and so may not give the best results. Instead of having a different diaphragm for such a tube, the manufacturer may make the necessary change in the position ot the focu- or he may affix a couple of slight glass project ions to suitable part- of the tube. Thi- is done in such a way that now when the dia- phragm i- fastened to the tube the wall of the cone will radiate from t he f ( iell- point . .1 -4. Author's radiating diaphragm attaohod to tul>o stand. radiatinu; cellular diaphragm invented by the author is for attachment io the tube stand and can be used with a tube of any size or shape. MEDICAL KLKITKICITY AND KONTCKN KAYS The conical portion is riveted or otherwise 1 fastened to a flat sheet of rigid material transparent to the .r-ray, such as aluminum. The latter has a suitable rim corresponding to that of other diaphragms by means of which it may be quickly attached to the tube stand and always at exactly the same place. The different .r-ray tubes have a mark, for instance, upon the cathodal prolongation, to indicate just where they must be placed in the tube shield so that the focus spot on the anticathode will be at the imaginary apex of the hollow cone. This position of the .r-ray tube i- usually the same as to height and laterally, but varies slightly in the long direction and must be determined experimentally for each tube before one attempts to use it for a picture. The appara- tus is only required for a gas-filled .r-ray tube, not for the (,'oolidge tube. (".XYN i if tin Author'* Radiating Cellular Diaphragm Xear or Atlochnl In tin .r-Run Tuht .- As far as concerns the radiation from the tube it gives the advantage of a small diaphragm without reducing the field depicted. Hut it has no effect upon secondary rays arising in the tissues of the body: and for pictures through the trunk, to show foreign bodies or calculi, it i- inferior to the Bucky diaphragm. Without this accessory it makes full si/ed plates of the extremities, the head, the chest, and of the stomach and intestines, which are better than those made with a plain ua-- filled tube. B/irL'//'* Ra\\rtions of the plate from every part of the patient exposed to the x-ray. Secondary rays arising from the partitions themselves produce an effect upon the plate looking like a reflection. This effect must he prevented by having the plate about 1 inch from the screen. Moriufi Bucky Diaphragm. This is placed between the patient and the plate. Primarily for the suppression of secondary rays arising in the tissues of the patient, it also sufficiently obstructs secondary rays from the glass wall of the .r-ray tube. It is a substitute for all kinds of diaphragms in the .r-ray tube or between the x-ray tube and the patient. And it is a very great improvement because the pictures may be 14 x 17 inches, and 'as clear throughout as a small radiograph made with a small diaphragm. And very thorough tests by the author have convinced him that it is superior to filters of any material or thickness between the patient and the plate. Originally comprising a collection of cells, Fit -Moving Bucky diaphragm (Viotor .r-Ray Corporation). it has been simplified and rendered practicable by making it in the form of a grid with parallel partitions, without cross partitions, thus having slits instead of holes. In the form shown in Fig. 525 the grid is trough shaped, forming part of a hollow cylinder 25.^ inches in diameter; the partitions are about -J inch apart and between them are strips of wood holding them in place at just the proper angle. When the .r-ray tube is in correct position the partitions cast only linear shadows, as in Fig. 52(w/. made with the grid stationary. These shadows become almost or entirely invisible, as in Fig. 520 b, if the radiograph is made 1 while the grid is moving laterally but like a pendulum, so that all the slots continue to face the .r-ray tube and to be equally distant from the anticathode. The patient rests upon a stationary transparent cover above the moving grid and the plate is stationary under the latter. Ti : cfittir irifh the Moritig Buck;/ ])/5 k.v., 'M) ma., 11 seconds for instance; for gall-bladder, gall-stones, or kidney and renal calculi: or SO k.v., SO ma., 7\ seconds or 90 k.v., 10 ma., 12 seconds for spine, hips, front part of pelvis. Abdomen supine with compression li."> k.v., SO ma., S seconds, for kidney, bladder, and ureter; SO k.v., SO ma., "> seconds, or 90 k.v., 10 ma.. 10 seconds for the spine, sacrum, and coccyx, using the author's graduated filter to reduce the Hiiflioirriiph nf rippr-ndix forty-cijnii hours nflcr li.'irium meal. Rucky dui- inten-i'\' ;it llic u';ii~t and so to secure sufficient ettect at the kidney and coccyx lc\d- \\itlioiit overe\po>ure in the middle. I''or a lateral view of the spine 90 k.v.. 10 ma., 20 seconds. For the chest the standard c\po-ure, but -ay about ">0 per cent, more than the usual time. l-'or the head, atiteri ipo-terior, 90 k.v., 10 ma.. 12 seconds; lateral, 7 sec- ond-. /)'"'/'/ I) ii />/: riii/n/ . S/titioiHirii. (i* (i Loi'nl i -_i r fur I''<>ri'ii/n liuilicx. It i- the author"- -unL r e-tion that without chanirinir the po-ition of the patient and u-in 1 ^ either the -ame or a ditVerent plate, the tube may lie moved 2', inchc- lateralh' and a seconl picture be made. The marks of the LTid Imiii an easy wav of .-eein^ the amount ot di.-placement of THE X-RAY 831 the imago of the foreign body compared with a stationary lead mark on the surface of the body, and from this the distance from the foreign body to the surface may be calculated. Stereoscopic picture* are also made with the Bucky diaphragm. The first position of the anticathode should be U inches to one side and the second 1.* inches to the other side of the center at which it would normally be placed. Development is decidedly different. The bones and other very dense objects, such as the barium meal or other foreign bodies, cast nearly complete shadows with a normal exposure. The Bucky diaphragm cuts r Fiji. olMih. Radiograph of frontal sinus with moving Bucky diaphragm. out t lie secondary rays which ordinarily darken up t he lihn in the shadow of the bones. The image, therefore, is never lost . the film or plate usually does not have to become black all over. It is only necessary to carry development to the stage at which the bones have become sufficiently dark gray to show details. The ordinary photographer would call it bringing out detail in the shadow-. And really it is much more like the development of a photograph than of the usual radiograph ol any thick port ion of t he body. The f th< Bnc'i:/i (linphriiyni is in radiography of the hip in very -lout persons and in lateral radiography of the spine. Filter Between the Patient and tin 1'lntf .- This accomplishes the same 832 MEDICAL ELECTRICITY AND RONTdKN RAYS purpose as the Bucky diaphragm, but less perfectly. The author recom- mends it (in the absence of a Bucky diaphragm) for every thick part of the hotly where the necessity for a large picture makes a small diaphragm unsuitable and where the greatly increased time of exposure is not objectionable. I'sing .'-cm. or 1-inch aluminum, A. W. Crane 1 uses an intensifying screen. 24-inch distance. 3*- to 4-inch spark. 3~> to 40 ma., and an exposure of one second per 3 cm. (1; inch) of tissue. The author's own filters arc 1. '2, or 3 thicknesses of roofer's tin. With one thickness. (I') k.v. and twice the usual time (with same number of k.v. and nia.1; with two thicknesses 90 k.v. and three times the usual time; and with three thicknesses '.)() k.v. and (> times the usual time. An example with three thicknesses of tin would be '.)() k.v., 10 ma., abdomen prone, 23 inches distance, duplitized film, two intensifying screens. I '_-. : _,. Heliograph* of dollar and penny. : nt i.-at hode. it- -hadow very t'aint because -eenndar' ray iroui the ./"-ray i- -paer liehind it and -how a i-li'ar ima^e ol the penny, whieh i- elo-e to II dollar i-l o-i to t he plate and fa-tin:i a < len-i. - i,:e : A in which the penny h. \ and 11 made al the -aiiie exposure. thirty ~econd<. Thi< u'i\'e< ;i picture \\ith \'ery much better contrast than ;i very much shorter exposui'e. -i\ seconds, without anv tin filUT. Tlie picture is even better than one without a filter, but with (>5 k.v., which f least resistance and if strong e-nough will spark across between the two pole's of the e-oil. In every .r-ray outfit movable metallic rods should be attached to each pole- of the- coil, and by turning these toward each other we can determine the 1 distance across which a spark will pass between the two pole-s e>f the coil. Two factors e'nter into the production of this distance: one is 1 he strength erf the 1 current, and the other is the resistance to the passage of the current through the 1 lube. With a ve-ry weak current, of course, we cemld not get a long spark across the space between the pe>]es of the coil even if the resist- ance in the tube were- very great, or if the- tube were disconnected from the coil entirely. In the hitler case, of course, the 1 only path ope 1 ]! to the current is acre>ss the space- betwe-e-n the poles of the- coil. This factor, the xtrcn to 0. or !), or, in some- rases, l.~> and e've-n o() ampere's are' pass- ing through the primary e-enl. The other factor is the resistance in tin- tnhi a;:d this is measured by turning on a standard strength of current, say amperes, ami approxi- mating the points connected with the two poles of the coil until a spark passes between them. If (' inches is the srivatest distance at which thi~ di -charge will take place', t he t ube is said to back up a (i-inch spark, or 10 have- a resistance equal te> a 0-inch parallel spark-gap. A tube with a resistance 1 of (> or 7 ine-hes we>uld be too high fe>r most kinels erf rudiographic work. Usually such a high vacuum and consequent high re-i-tance imply great penetration by the ray, and in some cases thi- i- desirable 1 , as in radiographing the- roots of leeth, showing the teeth right through the 1 jaw, and even the pulp canals in the 1 re>ots erf 1 lie teeth. Still even here 1 a moderately low vacuum is erfte-n better, a- it ti'ives so much belter contrast. \\ith an induction-coil the spin! re-meter, for ae-tually testing the leniitli of spark the tube will back up is necessitated bv the- pnsene'c erf tin- inverse discharge, which, while usually eliminated, may occasiemally invalidate 1 t he miHiampere reading a- a criterion of t he' degree of vacuum m the r-ray tube. An induction coil is very seldom pmvieled with a volt met cr. With a static machine the voltmeter is a useful gage, providing a PLATH THE .r-HAY x:;5 standard series gap is used and the usual power turned on and the machine giving its accustomed output. The spint remeter is not espe- cially suitable for use with the static machine. \Vitfi (in unfluctuating (/cncralor no spintremeter is required, as the resistance of the tube is shown at once l>y the consideration of the volts hacked up and the nuniher of milliamperes transmitted. "With a gas- tilled tuhe this reading, and the necessary regulation to make it right, had hetter he made with low-current values, which do not overheat the tuhe and act slowly enough to permit of accuracy. It will usually he found that 10 kilovolts and 5 miliiamperes at preliminary regulation indicate a decree of vacuum suitahle for many Kontgen-ray ])urposes. Turning on more power the current values will probably become (>2 kilovolts and 25 ma., and with a "Teat deal more power {)() kilovolts and about 50 ma. The ( 'oolidge tube technic is given on page 779. }\'ilh a transformer also the spintremeter may be dispensed with for daily use, hut it is essential for testing the accuracy of the voltmeter. The latter is practically indispensable, hut with great familiarity with the apparatus one may get along without the spintremeter and the voltmeter. The number of miliiamperes transmitted by the .r-ray tube, with a given ratio of transformation and adjustment of rheostat with a given strength of primary cm-rent, are a sufficient guide. As an example, it may be stated that with rheostat button Xo. 11 of the Waite and Rartlett transformer a current of 35 miliiamperes indicates a comparatively hard tube suitable 1 for making a radiograph of the bis- muth meal in the stomach in about one-fifth second with an intensifying screen. Other buttons of the rheostat would send 50 miliiamperes or more through a tube in the same condition of vacuum. It would be well for everyone using a transformer outfit to determine once for all the adjustment of rheostat and ratio of transformation for a weak current which will give 1 a reading of one-tenth the current to be sent through a gas-filled tube 1 when the usual radiographic current is turned on. The weaker current may then be used in regulating the degree of vacuum in the tuhe. Another method in which the vacuum in the tube is estimated is by determining the dct/rcc of penetration of the .r-ray with about the usual amount of current. 1. With an excessively low vacuum there would be no light visible at all in the fluoroscope. '2. \\ith what is ordinarily regarded as a very low vacuum the fluorescent screen in the fluoroscope is lighted up. but if the hand is held up in front of it the entire hand appears black and opaque, and, of course, the bones cannot be seen Through the flesh. ;>. With the regular low vacuum the bones show beautifully, almost black, the flesh clearly defined both from the much darker bones and from the brilliant light of the background. 1. \\ith a high vacuum the flesh and bones are almost equally transparent and present very little contrast. Twisting a watch chain around the hand, the links are seen so clearly through the hones that you cannot distinguish between those which are behind the hand and those in front . 5. An excessively high vacuum shows some light upon the screen and a grayish outline of the hand with very little evidence of the bones. To the experienced eye there is all the difference in the world between S3G MKD1CAL KLKCrUKITY AND KOXTOKX HAYS the poor image of the hand shown by a tube which is so excessively high that it is not giving out any effective .r-ray at all. and a tube in the contrary condition which is giving out a flood of .r-ray producing brilliant photochemic effects, but not pitched to the rate of vibration requisite for good penetration. In the ease of the tube which is a great deal too li!(/fi the tube shows very little luminosity, it is not sharply divided into a dark and a light hemisphere, and the dark portion is blotched over with patches of greenish light moving like a liquid. The resistance is high. "The iluoroscope shows very little .r-ray and a very poor but not black image of the hand. In such a condition a tube is worthless, but lowering the vacuum will effect a wonderful t ransformat ion. The milliampercmeter, which measures the quantity of current passing through the tube, shows a decided increase in current when the vacuum becomes low. and gives a useful warning of the approach of any great drop in vacuum during the exposure for a radiograph. The same diminished resistance in the tube is made evident by an increased amperage in the primary coil. In all these cases the same amount of electromotive force is behind the supply current and diminishing the resistance in any part of the apparatus increases the quantity passing through every part of it. A tube that is so loir as not to give any .r-ray visible in the fluoro- scope seems to be rilled with bluish or purple light (Fig. 444). There may be a blue streak extending from the center of the cathode to the focus point on the anticathode. Such a tube may look almost as if it had been punctured. In some extreme cases it is not possible to raise the vacuum to the .r-ray producing point by any means short of sending the tube to the manufacturer to be reexhausted with an air pump; and, of course, this is always necessary in case of a puncture. In many cases, however, the vacuum has temporarily been reduced to too low a level bv irases generated from heating the metal parts by too strong or too prolonged use or by incautious regulation of the vacuum, and when the tube has cooled these gases will be found to have been reabsorbed. The ViUnril oxmo-rctjulutoT on certain .r-ray tubes may be used to raise the degree of vacuum (p. TtiH, or the vacuum may be raised by turning; the current on and off for short period.-, and this may take five or ten minute.-' work. Other tubes come up quite rapidly if a fairly heavy cm-rent is turned on for a few minutes, and others, especially the heavy anode ( lundelach tubes, will come up it a reverse current is run t hroii'Ji i hem. With some of the Miiller t ubes t here is a raising device, coiisi-t inu of a side tube communicating with the mam bulb and con- taining a spiral of platinum wire; the positive wire may be connected with tin- ii i. -tead of with its regular attachment . t he negat ive wire being - normal position: and the normal current turned on. The current o iLih the platinum spiral causes absorption of gas to take umably i>v throwing off molecule- of meial which absorb md in that way the vacuum is raised in a verv short. irraimeinent for raising the vacuum of a tube is not. e--arv. The vacuum inevitably i- used, and each t line it i- use ei lucin^ it to t he propel' i legl'ee. fur .r-l-fini 7'///>r.'. Air is forced bv THE X-RAY 837 interior of the x-ray tube by a layer of unglazed and consequently porous pottery. Normally this partition is covered by mercury which cannot pass through the pores. Air pressure pushes and depresses the level of the mercury and allows the air to reach the porous partition through which some air is carried by suction and lowers the degree of vacuum. To Raixc, the Vftcnuni of an .r-h'ai/ Tube Without a 'Regulator. Con- nect the accessory aluminum electrode with the cathode and use a weak current. The connections are shown in Fig. f>'2S. With reasonable care it will not be reduced too low, either during the process of regulation or during the exposure for taking the picture. Hence, the vacuum will seldom require raising and then only to an extent which can be produced bv opera: ing the tube' for a minute or two. The sudden dropping of the vacuum of a tube during operation with a heavy current is due to overheating of the metallic parts, and liberation of molecules of gas which had been held in a state of condensation. This state of con- densation is of great importance in the manufacture and manipulation of .r-ray tubes. The material known as spongy platinum, the pure metal precipitated from a solution of one of its salts, will absorb and hold condensed in its pores three hundred times its own volume of hydrogen gas. This compression, of course, is accompanied by the production of heat, and one of the apparatus of a chemical laboratory before the discovery of matches was based upon this fact. Dobereiner's lamp consisted of a bottle containing iron filings into which a few drops of sulphuric acid were poured, the hydrogen gas, which was evolved, escaped by a glass tube at the tip of which was a bit of spongy platinum. Sufficient heat was produced by the condensation of the hydrogen in the spongy platinum to raise the metal to a red heat and set fire to the jet of gas. The flame, thus produced, was used for exactly the same purposes that matches are now. There is now on the market an attachment for the self-lighting of \Yelsbach gas-burners, consisting of 1 \vo little bells suspended over the burner. Kach bell contains a bit ot spongy platinum which becomes hot from absorption and condensa- tion ol gas and in less than a minute the gas ignites. hi using a heavy current, or even a moderate one for a prolonged exposure, the author has found it verv advantageous to watch the tube 838 MEDICAL ELECTRICITY AND HoNTOEN HAYS closely and to turn off the current for a while at the approach of this condition of excessive lowering of the vacuum from the sudden libera- tion of u'as by overheated metal. It is never difficult to see that this is coming. The inilliamperemeter sometimes registers an increased cur- rent from the lessened resistance in the tube, and at other times a sud- den drop to zero or to an excessive* milliamperaiic in a reverse direction . , the change in t he current , and a blue or steel trray color develops between the cathode and the anticathode. The current is turned off at this sto^e and the tube allowed to cool, and the exposure can then be con- tinued. Of course it is necessary that the patient and all the apparatus should remain absolutely still. In this way a piod picture may often be secured with an exposure divided, if need be. into three or more portion.-. If the current, on the other hand, is kept Turned on at the same rate after the vacuum Takes a sudden drop the balance of the exposure count.- for nothing, and if unduly p'-olonired may injure the patient, booking at a Tube in such a condition as this you may not even be able to see the bones in your hand. In nntl;imj x-rnij ////. s it is not by an}' means necessary that they shall contain an}' particular sras. Ordinary air seems as r one \\hirli has been sent to have a puii'-i , "'paired, or ha.- had to be reexhau-ted for any othei 1 rea-on, a CUlTcni ni el riricity has to be passed ihi'oiiii'h the tube |iract icallv THK .r-UAY 839 all the time that it is on the pump. This is because the simple applica- tion of an air pump would not remove the molecules of gas held in a state of absorption by all the different metallic parts inside the tube. These have to be liberated by the action of a current, and this must be passed through all the different parts of the tube, including the regula- tors, and it is not unusual for the process to take; one or t \vo entire days. The result is a tube containing so few molecules of gas that the vacuum will not fall below the line with ordinary care. The line has reference to the condition in which the presence of .r-ray is indicated by fluores- cence in one hemisphere of the tube, separated by a distinct equatorial line from the dark hemisphere (Fig. 520). Theoppositeconditionisshowu in Fig. ~)3(). To prevent a brand new tube from being blackened it has, of course, been exhausted while only a moderate current is turned on. and may si ill contain imprisoned molecules of gas which may be liberated the moment a powerful current is turned on. ! r this reason a tube is hardly even 1 to be used for radiography ur.ti! ii has been tr{>it occur on the inner surface of an >ome tubes develop a dull black oVpo-ii which interferes '.'I'll the efficiency of the tube; others -how a purple dis- 'oloration ui the L r lass which docs not interfere with the ' ' m::. the low( -1 vaciiui '.'. ill produce a brilliant ' i be L- the be.-i uiie for radiographs . and t hi- will, with most 'orn [in] : to a re,-i.~tance -oine\\ 1 1; , i | ( .-.- il, ;th -^ indies and to a .' one thickne.-.- of lead-foil. Thi.- would be the best \ very sliuhl ly higher vacitum would be bel tei 1 lid one ot aboil! '2 . inche- n -i.- ; ; , , ,, would be b It '! inches l-e-i-talic* . \\ ith the powerful THE X-RAY 841 current required for pelvic pictures even as low a vacuum as this pro- duces ;i penetration of five or six thicknesses of lead-foil; Xo. 5 or Benoist. Tcxtint/ the Quality of the .r-Rtnj. The author very strongly depre- cates the use of the hand for test i /it/ the quality of the x-ray from a tube. Everyone who habitually uses his hand for this purpose will, sooner or later, develop a painful and very probably a disabling and disfiguring inflammation of the skin of the hand. A considerable number of operators have suffered the loss of fingers or hand from such a cause, and one experimenter with the. x-ray, who was not a physician, is reported to have had chronic inflammation from this cause which subsequently was the seat of cancer, which ultimate!}' produced a fatal terminal ion. but we have not learned whether there was an hereditary predisposition or not. At all events the x-ray injury appears to have been an exciting cause 1 of the trouble. Of course, it is necessary for the operator to be thoroughly familiar with the Huoroseopic appearance of the hand and all other portions of the body, but no part of the living- body should be used for the dailv and hourly testing of the x-ray. The author's own jluoruwctct' consists of a thin board ineasurimr M by JL'l inches with a handle in the middle. Its major portion is covered by ./'-ray metal to protect the hands and face of the operator, while a strip about 1 inches wide extending across one end is covered with tin-foil, weighing an ounce to a hundred square inches and varviim 842 MEDK'AL KLKCTKHTl'Y AND RONTGEN KAYS BenoUt's improved radiorhromometor. The different sections, such as e clined toward the atiticathode n. Kach circular iin:i two of about the same thickness are near each other. With the screen we see only one lighted circle when there is the lowest degree ot vacuum producing any .r-ray: and with the hardest tube we can set 1 light in all the circles. 1 illard x rnfliOHclcwnnetcr is an important instrument for measuring the degree of penetration. The .r-ray -hint's through a silver disk upon out 1 quadrant of an electrometer and through an aluminum disk upon the other quadrant. The quadrants arc 1 charged by a source 1 of uni- S44 MKD1CAL KLKCTKICITY AND K<">NT< JKN HAY; form potential such as the direct 110-volt electric-light circuit. loniza- tion of the air hy the .r-ray results in its becoming a conductor and in a reduction in the difference in potential between the two quadrants and a change in their relative position which produces movement of the hand on a dial. The latter part of the apparatus looks like the dial of a milliampercmeter and is graduated in figures, which indicate the same penetration as the same numbers of the Benoist S.TouseX -c;dcs. The deviation is dependent ol the intensity or quantity ot the .r-ray. It depends upon the relative amount of rays passing through tin 1 aluminum as compared with that passing through the ! />'.- linlf-niliti ni(l ] measures the thickness of water in cent hnetefs which reduce- the .r-ray one-half or takes twice as lon^ '" pniiluce tlie -ame photoii'raphic effect as if the water were not there. T1IK X-HAY S45 This method can be applied by an apparatus which consists of a clock-work rotated disk with opaque projecting cogs exactly equal in area to the spaces between them. If this is in motion during the ./--ray exposure the plate under the cogs and spaces is uniformly exposed one- Fig. 538. Heinz-Bauer half the time. Outside this area are 15 stationary sectors of bakelite whose .r-ray absorption is similar to that of water. The thickness of the bakelite, in centimeters, whose shadow equals the half-time exposure indicates the quality of the .r-ray. Kays of half-value 1 are reduced half in strength by passing through 1 cm. of bakelite or of water and are about equal to Xo. 5 Benoist. Hays of half-value 2 are about equal to Xo. Benoist. i <>f Pcinlrutinn. A brilliant radiance is a necessity for ever Ml) MKD1CAL KLK( TKICITY AND RnNTCKN RAYS radiograph. Inn the decree :if penetration is an independent factor and is varied to correspond with the thickness or density of the part to be. radiographed. The length of -park which a tube will back up is a most valuable indication of the condition of the vacuum in the tube and of the penetrating quality oi the light. A complete change in the degree of vacuum during the expo-life would, of C(urse. render the remainder :>f the exposure u>eless or po.-silily deleterious. It is to be guarded against by watching the appearance of the tube both with the naked eye and with the fluorometer, as well as the two meters which show the amount of current pas-ing through the primary coil and the amount passing through the tube itself. Some t ubes become high after t lie current ha.- been turned on a little time, and when this is very marked it is rather a worse fault than the other. A tube which has a tendency to become low by the evolution of u'as may be coaxed along at a uniform degree of vacuum by several exposures so as to Lret the full time with a powerful current. But with the other kind of a tube you either have to resign yourself to an increasingly high vacuum or else stop and regulate the vacuum in the tube. This may take several minutes and the effect in such a case is only momentary. An automatic regulator (Queen) may in some cases be set so as to keep the vacuum from becoming too high. '! Lon'( r tin I urn a in in which come at a ri^ht angle to the axis of the tube. So that, a- a rule, the plate is upon the table, the portion to be radiographed rc-t in'j upon ! he plate, and t lie .r-ray t ube \\ it h its axis hori/.ontal and nt ii-athode directly above the center () f the plate. And, as a two conducting cords, either nf uncovered spiral steel ,-,,, inch thick, or nf tlun l!e\ib]e insulated _ wire wound on spring reel-, extend directlv from the pol in ih.- iwi 819 distant from the poles of i he coil, and the conducting cords do not rest upon any part of the tube stand. The special object is to have the wires extend in such a direction that they will not be anywhere near any pan of the tube except the lips to which they are attached. In this way the possibility of puncturing the tube is prevented. And this arrangement renders it easy to avoid sparking from the wires to the metal pans of the tube-holder or to the regulator of the tub*. Tube stands are provided with wooden rods to hold the conducting cords from undesirable contacts when this position is impracticable. A lar.u'e series of radiographs have been successfullv made with tubes of different makes in this position. It is a curious fact, however, that the greatest amount of heat develops along a line drawn per- pendicular to the surface of the anticathode, and under certain circumstances some tube.- which are producing practically no ./'-ray will .mive an occasional distinct flicker in a direction decidedly bevond t lie angle of reflection of the cathode ray when it st rikes 1 he ant icat hode. This, 1 think, is due to the irregular cathode ravs not being accurately locused on the anticathode. Some of them pass beyond the anti- cathode and strike the glass wall of the tube, giving origin to the .c-ray there. The Strength of Current in the Primary Coil. This is the great factor in ivtnilat ing the intensity of the .r-ray from a t ube. With some coil. - or t ran.-formers quite a beautiful .r-ray may be produced with as low as :-J ampere.- : while other tubes and coils or transformer.- are made to stand a primary current of 30 or 40 amperes for a short time. Other things being equal, t he heavier the primary current , the shorter t he time required and the thicker the tissue through which a succ< ssful radiograph may be made. A current twice as strong will produce a picture in about on"-tenth as long a time. Too heavy a current for the individual apparatus, of course, may burn out either the primary or the secondary coil: the excessive intensity causing the current to break through the insulation separating the different turns in the coils. A hundred dollars worth of wire may thus be ruined in a Hash. The fuses down in the cellar and elsewhere alonu' the feed-wires are to prevent such an accident and should be of -nrh capacity as to permit the passage of only such a strength of current as may safely be used. Kven 1 hen a too long-continued ilow of a heavy current through the primary will heat up the thin wire in the secondary coil and may break down its insulation. A 12-inch coil should stand a primary current of ! ID volts and 1 "> amperes for a minute at a time without trouble, and this should be lom:' enough tor the entire exposure tor any picture, and a very much shorter time will ordinarily be sufficient. There are very few tube- made which will stand so heavy a current for a minute at a time. A ' lundelach heavy anode tube, type bulb L't) inches in circumference and measuring '_'] inches to tip. has. in my hand-, stood precisely such a test suc- The majority of tubes will break down under such a strain. may puncture or the anticathode may melt, or the vacuum to such an extent that the production of effective .r-ray other tubes may be used with as heavy a current as termiiteiit exposure to prevent the tube from becoming A primarv current of ID amperes may be considered as for ireneral radiography \\ith a I'J-incti coil, and am er rat in^ < r i iver. with a heavv am de < >r a v ; MKDK \i. KI.KI 'TKierrY AND K<>.\T<;I:N KAYS cooling device, ought to stand this long enough for a picture. Here a^ain. ho\\ ever, it' tin- time i.- more than forty seconds, most lubes will produce a better picture if the e.\])osure is interni])te(l, Kven one of tin- thin anode tubes may In- used in this way with such a current ; and the fact that tln-v contain a much smaller amount of metal causes them to maintain the .-a me decree of vacuum better than some ot the heavier tube-; still, the heavv anode tubes are preferable tor radiography. The weaker primal'}" currents ot i> to (i amperes work very nicely with an ^-inch coil and with tubes of 25- to 10-centimeter rating. As stated elsewhere. aii\" conditions which produce a good iluoroscopic image of the part in <|UesUon will produce a good picture, if the plate has the proper derive of sensitiveness and the exposure i.- properly timed with relat ion io t he ot her factors. ( lenerally speaking, the intensity of the radiance is increased or diminished bv usinu' a stronger or a weaker current through the primary coil, and to a irreat extent the same instruments regulate both the amperage and the voltage of this current . The lid-volt direct current of the electric-light circuit passes through our liquid interrupters and iron wire rheostats, and enters the primary coil as a current of only MI or (Ml volts and with a volume of 15 to 1* amperes for routine work. Ri rrenieterx, in one the hand i- moved by the various lengthening of a wire which becomes . the passage of currents ot different volumes; in the other the hand i- n ov-d bv t he effect of a current t hroiiLih a wire, or a coil of wire, h'j a magnetic needle and tending to r;msc the needle to a-sume a po-in'on ; ri-jht angles to the direction of the current. This is a v -imple matter and the readme is in amperes or milham- ' ' mav be, regardless ot the volt n ire ot t he current or 1 he '' ' ' ' e circuit. The same tvpe.- n| m.-t rumeni sei'\'e as volt- . in the "Taduation of the in-trumeiit in volts it i- re-i-taiice m the circuit -hall be a constant, not a With a uniform re.-i-tance the amount of the | >ro| >ort lonal to ; IH ' the amount of the v, hat ' leilect - i h< hand, bu' i' al.-o indicates t he "ci .'. i :'' ; i drive- 1 1 mi of current i-'ance. Tin- gradual ion.- upon amperemeters. Tin: .r-iiAY 851 and voltmeters arc always made by comparison with standard instru- ments. It would be difficult to construct one on entirely theoretic lines and have the graduations turn out exact ly accurate. Another apparatus ior reducing the voltage of a current for .r-ray purposes was published by Lallcmont .' It consists of a jar of dilute acid through which the current passes between two lead electrodes. ( )ne of the electrodes is more or less conical with a cruciform cross-section, so that the deeper it is immersed in the liquid the greater the surface of contact, and. consequently, the greater the volume of current trans- mitted. Fart of the current passes through the liquid, so thai if 120- volt direct current is shunted through dilute sulphuric acid, 1 Beaume, the voltage is reduced to about GO. Very many of the operators in Europe use a current of GO or SO volts for x-ray work, obtaining it usually by means of a shunt-controller. In the I'nited States, however, most of the .r-ray coils are made to use the 110-volt or even the 220-volt currents, reduced only slightly in voltage by the ordinal 1 }' resistance of the rheostat and interrupter. The regulation of volume of the prinian/ current for .r-ray work varies from o or 1 up to 30 or 40 amperes, according to the nature of the pic- ture to be made and the character of the tube and other apparatus em- ployed. Two different forms of rheostat are in very common use for regulating the amount of current admitted to the apparatus from the electric-light circuit. The current in the latter, of course, is perfectly enormous, as is easily discovered by short circuiting it, for example, by touching the outlet and inlet wires with a pen-knife blade. There is a blinding flash of light and a piece of the knife blade is actually burnt right out. With any properly installed system of wiring there are fuses in the cellar and elsewhere which burn out when an excessive current like this is turned on by accident or by mistake, and the whole system becomes dead almost as soon as the flash occurs. Without such protection by fuses any electric-light current would be a source of the very greatest danger from fire, and even with it the very greatest attention should be paid to the proper insulation of the entire apparatus and wires. It is important to remember that the secondary current is of such high tension that it will break through practically any insula- tion, and that the wires leading from the coil to the tube must not be allowed to touch any other wires. If they do there will be a spark and an odor of burnt rubber, anything inflammable may catch fire, the fuses all burn out. and the current stops. The insulation of both wires is burnt through and then you have a couple of wires with permanently defective insulation. This last result is not so important in the case of the wires leading to the tube; they are not supposed to be fully insulated and, indeed, some of my favorite cords are fine bare iron springs. And in these cords the volume of current is very small, some- where around 2 to 10 milliamperes, from which the danger of lire is nil. Am! aii'ain. these wires are only charged when in actual use and are then nded in mid-air between the poles_of the coil and the tips of the possibilities we may compare n to a water-main passing through a city street, tapped here and there liy small pipe.- leading lo faucets m the different houses. At these faucets the p res.- life n >rre.-poli< Is to 1 lie difference between the level of the faucet all'i the level of the reservoir ''rom which t he water come.-. The mulcts are small and the amount of water which can escape l.- onlv t he amount \vhich that pressure can torce through a hole of that si/.e, hut if \\ e make a larue break in the main, we will ha\'e an escape of water threat enough to undermine the house if it i- not promptlv checkeil. The quantity of water and the pressure are ;il\v;i\-s there, it is oiil\' that ordinarily the openings are so small as to present -uch friction or resistance that only a stream of the desired magnitude can escape. In the case of the elect nc-li^'ht circuit there i- enough volume of electricity in the street mam to run a number oi la ry its resistance which corresponds to the size of the opening at the water-tap or faucet. Diminish the resistance and as heavy a current may t >e obtained as is desired, do away with the resistance altogether by short-circuiting the current, and vou have done almost the equivalent ot making a break m the water-main and you iret a perfectly tremendous discharge, but. t'ortiiiuiTely. one which is almost instantly cut ot'f b\" the burning out ot the fuses all alom: the line from the apparatus to the mam. I'sually the apparatus itself will escape unharmed, but. of course, there is always the possibility of burninji out 1 he pnmar\' or secondary coil and chanjrin from '.i to II amperes; this i- without anv rheostat and simplv the 1 '' [jfesented bv tlie coil it-ell aiid foi 1 a \'ery ^reat inan\' radio- nil- this -trenuih of current \\-ill be found to be ample. Rate and Character of Interruptions. In the Calilm-U oYSiiunn . for the\- mad' 1 the invention independent lv and at about t he - , ' tne. ! he priori! \' I t hmk belong! IIL: t o < 'a !' [wi '11. i he suppl v current lie -ul] ilmric acid, about one to six. ( )ne lead m an inner beaker ol 'oiii:h porcelain through i ablisli ci immunica t ion \\ it \t acid in t In- outer ' ol her leai 1 elect n ule. h doc.- n< it mat ter which i- - ne-^at i ve, \\ lien a heav 1 r-ij ri'eni i< passed t hl'oiii:h re-i-1 alice i- . . I t hi pin-holes, where or i- ver; -mall. Tl 1 1 id < ir act ually ';'-- point- ai lin-holes and for a '. - i nei Mon i- broken. The en - in- to How a.ii'a in if escape-. some int efl'll] itel'S ' ' I I in e - a Hi 1 1 1 1 1 1 e . 'I fluid ' h i'-li elect n ilv-i- t a kes <( ra 1 i-d at ! he 853 negative and of oxygen at the positive electrode. This docs not seem to !)< of importance in the production of the interruptions, its practical hearing being the fact that a mixture of free oxygen and hydrogen is explosive if ignited by a spark. Such an interrupter should alwavs he provided with free ventilation. The operation of a Caldwell interrupter is accompanied by the production of irritating sulphurous acid fumes and l>y heating ot the liquid. \\ hen the liquid gets too hot the inter- rupt<'r will no longer act and it is desirable to have several interrupters and simple switches to connect different ones with the coil. If these have pin-holes of different sizes we have the added advantage of being able to select the si/.e best adapted to the case in hand. The smaller the pin-holes the more rapid are the interruptions and the less powerful is each impulse sent through the tube bv the secondary coil. This is a desideratum for treatment and for the lighter forms of radiography, while for the heavier radiographic work such an interrupter should have large pin-holes. With the small pin-holes the primarv current when turned on full is only o or 1 amperes, while with large holes it mav be as heavy as 11 amperes. There are. of course, modifications of this simple type, and in one of them the size of the communication between the two portions ot fluid can be regulated by the motion of a conic plug, which more or loss completely fills the hole. l"p to the limit of its capacity the Caldwell interrupter is one of the most satisfactory in the production of a brilliant steady .r-radiance. I he II < Inn It / iitci'i'H jitcr consists of a single jar of dilute sulphuric acid. The i icgat ive electrode is of lead : the posit ive electrode or anode , being a platinum rod enclosed in a closolv fitting, very tough, porcelain tube mid the distance that it projects beyond the end of the tube can be regulated. The greater the surface of the platinum point exposed to the fluid, the more powerful is the current and in a general way the slower are the interruptions. When in active operation the platinum point is seen enveloped in a regular flame and the fluid about it i- cloudy and fiercely agitated. The probable cause of the interrup- tions is the production of a layer of steam covering the whole surface ot the platinum point. There is. however, vigorous elect rolvsis going on with the generation of hydrogen chiefly at the negative pole and of oxygen chiefly at the platinum point forming the anode. And owing to soli-inductance and an inverse current in the primary circuit, there is al-o. to a lesser extent, a liberation of hydrogen at the anode. The bubble- o| gas do not form a sufficiently uniform covering on the anode to account torthe interrupt ions, t hough t hey doubtless exert an influence upon the nature of the interruptions produced. With this interrupter the iluid becomes hot and the apparatus fails to work after continuous use, so that it is necessary either to have one containing a very laru'e amount of liquid or to have more than one interrupter. The \\ehneh interrupter is often made with more than one anode and if so the plati- num tips may be ot different sixes. There is the same necessity tor vetit ilat ion ni order to avoid explosion. The \\ el melt int errupt er must not be run with the poles reversed. If the negative wire is connected with the platinum point and the positive wire with the lead electrode ' the interruption-, it' produced at all. are of a deeper and rougher sound and the current very quickly corrodes the platinum point. For this reason the \\ el melt in t errupt er is not suit able for use wit h an alt era at ing current, or. if it i- so used, the expensive platinum point should be N>1 MKDH'AL KLKCTUli'ITY AND IJuNTliKN KAYS replaced by one of copper wire which can lie renewed as fast as it is consumed. The Caldwell interrupter may he used with an alternating current hy introducing an tilu/iii/inni r< // into the supply circuit. This is a cell tilled with a ti per cent, solution of Rochelle salt; the two electrodes beim: of aluminum and lead respectively. This acts hy suppressing the impulses in one direction and, of course, is much less efficient than a commutator or any form of dynamo in which the alternating current generates a continuous direct current. Still, a Caldwell interrupter and an aluminum cell form a simple and inexpensive combination and produce a very good .r-radiance for treatment or for the lighter demands oi radiography. Mechanic interrupters are made on two different principles. In the older type the contact is made and broken by the vibration of an armature in front of an electromagnet. The primary current, or a shunted portion of the primary current, parses through a coil of wire surrounding a core of soft iron which becomes a powerful magnet the moment the current begins to flow. This pulls the armature, which is I'lLT. ."i-lO.- Improved <.,Mie<'M independent vibrating interrupter. on a .-prinir. 1 oward it , and thus the connection is broken and, of course, tin- mm ceases to he a magnet and allows the armature to spring hack to its original position, where the contact is again made. One of the supply wires leading from the wall socket to l he apparatus is cut in two and one end is connected with the armature and the other is con- nected with t he metal against which the armature is pressed bv the spring. The rate () f vibration depends partly upon the weight of the armatun and partly upon the distance it has to travel, and this is adjustable hy means ot a screw. Such an interrupter of an improved de.-imi is shown in FILL'. ">10. The interruptions produced are than is i he case with a liquid interrupter and it is not : the heaviest currents, so that its utihtv in radiography is !. (' is especially useful for tivatmeni work because ill day long. M < I'lni nic I >it< rni /il< r. \nother mechanic interrupter 'en developed, by diifei'eiit manufacturers in America -lightly different lines. Iv-sent ially it depends up"!) in of a \\heel in which two opposite spokes are toi'i:.' ; permanent mamiet. This i- placed near the end of TDK .r-KAY 855 the iron core of the induction-coil. The hitter, of course, is a powerful electromagnet with a certain polarity during the llo\v of the current, and ceases to he a magnet after the current stops. The positive pole of the revolving magnet when in a certain position is attracted by the iron core of the coil, and this attraction causes the wheel to revolve into such a position as to bring this pole of the magnet as near as possible to the iron core. By the time it has reached this position the break in the circuit has occurred, the iron core is no longer an electromagnet, and the momentum of the wheel carries it around to such a position that the newly and oppositely magnetized iron core attracts the other pole of the revolving magnet. The motion is a continuous one, resembling that of a windwheel or a water-mill. The rapidity of revolution may be varied by changing the distance between the revolving and stationary magnets. The com act occurs between two flat metal surfaces, -^ inch in diameter, and there is considerable sparking. The interrupter is contained in a box lined with sheet-iron to prevent the sparks from setting fire to the box or neighboring objects. If too strong a current is turned on, or if the interrupter is not working properly, the contact surfaces may become welded together. This is not a .serious accident, however, for usually only a small part of the two surfaces adhere to each other and they are easily separated and smoothed again. A con- denser weighing five or ten pounds is re- quired with this interrupter and a rheostat with a minimum of S and a maximum of It) ohms resistance. This will interrupt a current of as little as \ ampere and as much as 5 or 10 or with special con- densers even 20 amperes. It is especially useful for high-frequency currents and for .r-ray treatment tubes for contact application where the strength of current must be very small. It is made especially for the 1 10-volt direct current, but can be used with an alternating current and an electrolytic rectifier. It causes a Miiller No. lo .r-ray tube to produce a suitable radiance for therapeutic use. It is available also for radiography and gives better contrast, but takes a little longer than the liquid interrupters with very much heavier currents. A 5-ampere current with this interrupter will produce a radiograph of the frontal sinus in a minute which is about as good as that produced by IS amperes with a Wehnelt inter- rupter in thirty seconds. \\hid Interrupter* trith Mcrcuri/ J<1 and Illuminating (itt* Arc Xupprcxsion. Drault and some of the other European manufacturers make a wheel interrupter on the same principle as the Wappler inter- rupter, except that the motion of the revolving magnet actuates a mercury jet interrupter (Fig. 542). The interruptions take place in a closed iron cylinder filled with illuminating gas which is non-combustible in the absence of air. This prevents the oxidation of the mercury and iron which takes place when alcohol is used to suppress arcing. The apparatus, therefore, requires less cleaning. The same claims are made for wheel t'<>r it a- I'nr the Wappler wheel interrupter, hut, of course, the mereurj' turhine make.- it a little more ((duplicated. A dan.u'erous explosion \vouM occur it' it were started when full of a mixture of air tun I illuminat- ing Li'as. Mi / one in \vlucli the contact is nmde or hroken, either hv the throwing of a revolving jet of mercury against metal connections, or the (lipping of a metal connect inn into mercury. In either case the power i> usually supplied hy an electric motor. The mercurv turlniie ran !>< made for a very wide ranire ot speed and can l>e run foi 1 a Ion u; time. 1 n l>oi h t he mercury interrupters there is a layer of '1 nr oil to suppress the spark, which would otherwi.-e he excessive and whidi wouM cause the making and hreakiliii loj.-- 'I hl~ is made hy 1 he Sa n it as ( 'oin- p ' ' of herlin. and is a mercury interrupter m which the arcing is .'--' i hv petroleum oil. 'I he metallic vessel con) a mum' the ;'- at a hi'_;h rate of speed. The mercury i- held against .'--'! hv centrifugal force and 'here are two insulated ak t he con t act I iet \\ een a m< t a I rod connect hill' wit h tlie revolving mere n" The claim i- made for it it h any voltage, or thai it can he u-ed wit h a s1orap:e- irecl eleci ric-li'/lii current . 1 1 is al.-o said i o < di-charn'e ;han I he \\elmelt or the mercury jet . '. I'lie i'adiouraphic and Huofo-copic rc.-ulls .-hoiild he ; : ly hei t < -r. fat- i iili; '<-/ Ml, ri,!!. Oi'ilinuri/ vibrating intcr- riijitir.^ of the type familiar in the faradic coil are not suitable where heavy cur- rents are to be employed. A condenser is always re- quired when such an inter- rupter is used. Among the earlier types of apparatus was the Edison make and break wheel mak- to L'0.000 revolu- nute when run by separate motor. It required a blower to extinguish arcs and made a ureat deal of noise. The switch was so arranged as to start the inter- rupter before the primary current was turned on. The Willyoung interrupter was similar, but the contact points were immersed in oil. which reduced the arcing and noise. The Jnlnixtnn interrupter, made by the Westinghouse Company, is a mechanic interrupter in which an electric motor rotates'an inclined Caldwell or Simon and with the Wehnelt interrupter no required, but for any form of mechanic interrupter a i'iit'i/1 //.-' / is necessary. This consists of a number ot sheet- of tin-foil in two -erics of layers, one series connected with one wire and the other series dovetailing between and connected with the other wire. All these different pieces of tin-foil are insulated from each oilier by >heets ot paraffin paper or mica. When a current of electricity passing through a prnnarv coil is suddenly interrupted, a certain amount of charge, or difference in potential, is found to be present in the primarv coil, and . this, of course, produces a current in the prnnarv coil which will have dischare of th MKDH'AL 1.1. K< THlrlTY AM) Kl >.\ Tl. K.N HAYS or difference in potential, and as a matter of fact its presence does actuallv make the difference between a successful induction-coil and one which will not work well. Its function is roughly to lie compared to that of a llv-wherl in machinery. The necessity for a condenser in any coil with a mechanic interrupter adds greatly to the weight of the apparatus and makes it somewhat less available for a portable outfit. The Self-inductance in the Primary Coil. The primary coil is of comparatively thick wire, wound upon a long spool, and may be in a single layer or in several lay.-rs. If the latter, the self-inductance may be variable by means of plugs or screws, so that the current may pass through onlv one layer or through two or more. In the latter case the connections may be such that the different layers in use form one continuous circuit like the thread on a spool, or they may form two or more parallel circuits. There is an induced current produced in any wire near another in which a current of electricity passes, and this is produced even if the two wires in question are but parts of the same wire coiled in several turns. Lewis Jones, 1 of London, has published very valuable tracings showing the difference between the waves of electricity produced in the secondary coil by varying the self-induction in the primary. He finds that for therapeutic purposes (faradic coils very much smaller than the induction-coils for .r-ray work) the secondary current, produced with a small self-induction in the primary, is more effective in producing muscular contraction and less painful than with large self-induction. The difference in the tracings shows that with small self-inductance the make and break currents reach their maximum at one bound and come down to the level by a short steep curve; whereas the return to the /.era line in the secondary current when there is large self-induction is by a long inclined line. In the case of .r-ray coils the practical value of variable self-induction consists in the fact that a tube \vith a high vacuum generally works better with great self-induction and vice versa. This is because the tube with the higher vacuum requires a more powerful secondary discharge, and this is just what is produced by a primary coil with large self-induction. Disconnecting the .r-ray tube and observing merely the spark passing between the poles of the coil, is about twice as long and twice as heavy with high self- as with little self-induction. 'Die author has made such an t with a 12-inch coil, a Caldwell interrupter with small holes, o.-tat resistance all out. so that there i< no external resistance t current. \\ith the long primary winding and -inductance a heavy spark passed across a space of e small self-inductance a lighter spark passed across inches. In the case of the greater self-induction heavier spark the amperemeter showed that only g t h rough t he primary coil, while in the other case re flowing. The longer primary coil of w're, of leavier secondary discharge represents an increased me, so t ha t t here are t wo ways in which the quantity ing through the primary coil is varied bv conditions The same thing which is true of the spark between pole.- of the coil is al.-o true, in a general way, of the pon an .r-ray tube. I'ut heiv there are several other :i;.l. ( 'ct . s, I'JUl : Trans. Arclii\ < d'l !lcc. .Mr that the instrument i- of service in estimating the :i iwer of different coil- and also for showing the condition of the tube at every in-taut of the exposure in making a radiograph. To a certain extent it indicates the effectiveness ot the ray produced, and in this way -erves a- a guide to the length of time required for the exposure. The same, of course, holds true in regard to the therapeutic use of the .."-ray. All thi-. however, i- valueless and even mi-leading unless corn- wit h the many other factors already alluded to for obtaining or .ogni/ing the proper quality of radiance. It i- e-pecially important ot to rely upon this milliamperenieter on the secondary circuit to the 'X'-lu-ion or neglect of the amperemeter on the primary circuit. The latter indicate- the amount of current admitted to the apparatus; it -! .- hetli r there is danger of burning out the primary or secondary rheostat or any of the fuses. If one i- doing heavy work at >] itely ' ntial to the -afety of the apparatus to have an on the primary circuit, and with it one can very well ac- de-irablc effeH \vitliollt the 1 1 ] i 1 1 la 11 Ipefeniet er oil the ; lary circuit, thi- being in radiography with an induction coil onlv i ' .' ;icci -ory. but essential with a tran-former. etneter gives exact re-nit - : I'fect . ] ig t hen- i.- al>o ;i good -omet inn - thi c. As a rule,, however, le inverse (lischal'ge I he ilireel (li-charge is I. 1: ..':..-. : " i- 1 .",. I 1 . ni."i, ii. :;nii. Mil deficient : and considerable inverse discharge always produce- excessive wear and tear upon t he { ulie. The Point and Plate Parallel Spark-gap. This may he u-ed as a sort of valve to suppress the inverse discharge. It is placed between the poles of the coil and so near together that the discharge in one direction (/. e., when the plate forms the cathode and there i> an inverse discharge) will pass across the spark-uap. If the distance is properly adjusted t he i list-harp- in t he opposite direct ion cannot cross the a ir-u'a p. but will be dri\en through the tube. The point should be connected with 1 he cat h ode and t he plate with 1 he anode of the tube ( Fi^. ^\^i) . Measurement of the Difference in Potential at the Poles of an ./'-Ray Tube. A -tatic voltmeter may measure the difference in potential between the TWO poles of an ./'-ray tube and consequently the resistance of the tube. The voltage is so ^real that (iaif'fe'has adopted the expedient of connecting the poles of the tubes to a series of condensers. The armatures of one of the condensers are connected with the static volt mot or. The fraction of the voltaire thus measured is one divided by the number of condensers. The uTaduations on the voltmeter may be in volts or directly in decrees of the Henoist radio- chromometer. but the graduation must be done for The particular apparatus that the voltmeter is to be used with. 'i p< i'( N ond I'ncl'-uj/ in u (icix-jUlcd Tiibi ill I //(// and the back-up or .-park equivalent \ inches, if now the power is increased so that the milliampere.- become '_'(>. it will be found that the spark equivalent has also increased probably to about f rncnui/i is the same, however, and i- found by dividing the square "t" the number of inche- back-up by the number of milliampere.-. the same relations between the miliiamperage and spark-gap as with the ma filled t uhe i pame *n!l'ts a ,,,l other foreign bodies embedded in the flesh may be : Iv seen with the fluoroscope and in the radiograph, and still it may In- somewhat dillicult to say at just what depth they are located in the tissues. This information may be directly gained in any portion of one of i he limbs by making t wo successive radiographs at a right angle to each other. It will greatly facilitate the surgical removal if a metal marker like a small -hoi or a very short piece o| heavy wire be fastened u it h adhesive pla-t er to mark the \v< mi id oi cut ranee. This should be in I he plate and. therefore, at t he center of 1 he first radiograph and -hould be at t he ext reine edge of t he image o! t he limb in t he second. Iii Fi-.i's. ."in and ."; 17, referred for examination by I )r. \Yadhams, the lateral radiograph -howed a needle broken oi'i in the heel ' inch in from oiind of entrance ,-md extending upward and backward tor 1 inch. Tl ipo-terior radiograph sho\\ed that the needle did not incline ,' . . m a median plane. h was easy enough for i :. - ' tin ud remove it . W. M.l'i . . .. if New York, was among t he fir-t t o suggest fa.-tening 1 ' ' i o 1 1 e -kin eit her tow.- 1 rd or away from t he pi a t e in coii- Ilio, litlr;,! ion of ! he M a ckel l/Ie-I )a Vld-ol I localize!'. THE X-KAY 805 in. o4G. I.neali/ation of noodle in heel. Lateral \ie\\- showing needle and metal market 860 MKDICAL KLKCTHK 1TY AND ROXTGEN KAYS Foreign substances in any part of the trunk may be localized by making two successive radiographs upon two separate plates with the body in the same position with reference to the plates and with the tube shift (>d a certain distance to one side for the second picture. A calcula- tion based upon the distance from the .r-ray tube to the plate, the dis- tance to which the tube i< displaced laterally, and the resulting displace- ment of the image of the foreign body will give the distance of the latter from the plate. THE AUTHOR'S METHOD OF LOCALIZATION ' The .r-ray tube has its anticathode at a distance of 14 inches from the plate for the, extremities and is moved laterally 2 inches after the first radiograph. And for the trunk or head the distance is 21 inches and the displacement 3 inches. A lead mark is fastened upon the surface in contact with the plate, replaced afterward by a mark with Fig. -VIS. Position of the image of the foreign body in the thigh in the first radiograph. iodin or nitrate of silver, for a guide at the time of operation. A gal- vani/ed wire net ''i-inch mesh" which with the thickness of the wire has 7 subdivisions to the linear inch is laid over the plate. A double expostire shows the lead mark and the wire net stationary, but two images of the foreign body. The meshes enable one to determine amount of displacement, selecting the same part of each image, and the appended tables enable one to determine the distance of the foreign body from the plane of the plate, and the relation of the foreign body to the lead mark i- also shown. If two plates are used the number of subdivisions i ra rv -t ud v. ; Sinclair TOIIM-V. New York Mod. .Jour.. .lulv ',. l 5.8 6.1 6.5 6.7 7.0 The Mackenzie-Davidson Localizer. This is tin 1 prototype of a clas< ot apparatus designed to u'ive this information in a mechanical way. ''. i ., without mat hnnat ic calculation. The photographic plate for each picture is placed under cross-wires, whose position may be marked upon the body and who>e position is radiographed upon the plate. The aiiticathode of the tube is placed at two definite places for the two successive pictures HIT. .Vil). After the plates have been devel- oped one i- placed in the locali/er so that the cross-wires of the latter coincide \vith the imau'e of the cross-wires on the plate. A thread is fastened at the imam 1 of the foreign body and at a pointer which is held iu-t where the anticnthode was placed for this picture. A thread is drawn in a Minilar wav from the iniauv of the foreitrn bodv on the other . ... on ! In IH ice u pied 1 iy t he ant icat hode. The place where ' cross ;- the place occupied by the foreign bodv rela- mraphic plates l"\( I . Strohl's method of localization 1 i- one of the mos! interest ine o\'er the recuni- ' I- r-ray I ube \\ oiild be underiieat h and !'reel\ p mox'able in a \bovc the .c-ray tube and ino\-'uit: \\ith it are two . about 1 inches apart. The .r-ray tube i- ino\'ed to -U' 1 ' itiuii thai the .-hadow of one wire fall- upon a certain p 'int in i ne innu'e ,.f i he f. irciu'ii bod\- and a marl;er i- laid on the TIIK .T-HAY 809 screen at that point. Then the tube and its wires are moved so that the shadow of the other wire falls upon the displaced intake of the same part of the foreign body, and another marker is placed there. The ap- paratus is accompanied by a rule or flat measure upon which the dis- placement is noted. The graduations are not in actual centimeters or inches of displacement, but show directly the distance to the foreign body from the plane of the screen. No extemporaneous calculation and not even a reference to a table of values is required. A table en- ables one to read the distance- from the plane of the fluoroseopic screen to the foreign body indicated by the measured distance to which the linage has been displaced. The surprising feature is that the x-ray tube does not have to be placed at a -perilled distance from the fluoro- seopic screen, but may always be at the same level, while with a small part of a thin patient the screen may be at a level several inches different from that when a large part of a stout patient is examined. It reminds the author of his own astonishment at being able with the orthodiscope to draw an actual size picture of a key while seeming to trace the greatly enlarged fluoroseopic image 1 of the latter. The principles involved are somewhat similar. If one were to extemporize such a localizer it would be unwise 1 to calculate the measure of displacements and depths; it would be desirable to make a sufficient series of actual measurements of the displacement shown by objects at measured distance below the screen. 1 The Hirtz Compass.- This is an apparatus applied to the surface of the body at the time of operation to indicate accurately the position of a foreign body. It is adjusted by a series of fluoroseopic, radio- graphic, and mathematical procedures which are succinctly described by Bowen. :: The Cannula and Harpoon Method of Localization. This is a fluoroseopic method largely employed by the French in the World A\ ar. The harpoon is a straight needle barbed at the end like a fish-hook so that when pushed through the tissues till it touches the foreign sub- stance 1 it stays there until the time of operation. The harpoon is guided in the 1 right direction by the 1 cannula, which does noi it>e-lf enter the 1 flesh, but is attache-el to a forked frame and pa>ses through a fluoroscopie sere-en. The- patient's limb, for example, is between the two forks of the 1 frame and is turned so that the 1 image 1 of the foreign body is separate from the bones. The cannula and a special part of the opposite 1 fork are brought directly in line 1 with the foreign body and the harpoon thrust through the tissues into contact wit h t he foreign body. The Parallax Method of Localization.- Several excellent devices, including Annulet'- ( Ira Hirer's, determine fluoroscopieally the distance at which a movable metallic test object niu-l be from the fluorescent screen in order that the- displacement of it- image 1 may equal the- dis- placement of the imaire of the foreign body. Antfinr'x Device for A />]>h//i/(l KariioriraphicaUy. 870 MEDICAL KLF.CTKICITY AND RONTGEN HAYS stoop aluminum stop-ladder upon each step of which is a lead figure, numbered from 1 at the bottom to 8 at the top. Two exposures arc made on the same or different plates. If the displacement of the linage of the foreign body exactly equals that of figure 1, for example, then it- is at tin* same distance as figure 1 from the plate. Or if it is more 1 than that of figure 1 and less than that of figure '2, the foreign body lies between those two distances. It does not make any difference what the tube distance or displacement are or what are the height of the steps, but there should be some fixed mark in contact with the plates when two are used, and the author's wire net is useful for comparing the displace- ments. No table of values need be referred to. DEVELOPMENT OF JT-RAY PICTURES The dark room ought to be entirely free from ordinary light, either daylight or artificial light, except as allowed to enter through ruby and orange glass or their equivalent. If it is a room with windows no number of dark shades and ordinary blinds with slats are going to exclude the light sufficiently. Kit her all the panes of glass must be treated as described later or else solid board shutters must be provided which will close so accurately as not to admit a solitary ray of light. In order to use the daylight it will be necessary to have all the panes which are not securely boarded up consist of one thickness of ruby and one thickness of orange glass, or else the glass may be ordinary colorless ground glass pasted over with two thicknesses of the red paraffin-coated paper used in the original packing of sensit i/ed plates, and one t hickness of the orange paper known as "post-office paper. 1 ' Such a window should be shielded from the direct rays of the sun and if the window is very large, or if there is more than one window, it is better to absolutely darken all but about 2 square feet of one window, and treat just that area so as to admit only safe light. Kxeollcnt outfits are made by the Polyphos Klekt ri/itats-( iesell- schaft. of .Munich, of the nature of shades for ready application to the windows of a room in order to convert it into a dark room. The dressing-room, as found between the front and back rooms of many city houses, forms an excellent dark room. 1 The doors usually have ground glass panels and these may be- prepared with red and orange paper, and a good strong artificial light of any kind, placed close to the outer surface of one of the panels, will send just the right amount of safe light into the dark room to enable one to work easily and to see the plate rlearlv enough to regulate the degree of development. In i he same way if the dark room is a specially constructed box-like attair. a small window of rubv and orange glass mav be cut at a con- venient height and the light placed outside. The ( 'nt>/>t r J!( iritf //'.">l2 shows the' plate before development. It is a deael white 1 and as opaque 1 as thin porevlain. After a certain length of time 1 in the developer an "image" becomes visible upon the 1 plate; it is produced paquo by the part of the plate more 1 directly exposed to the .r-ray darkening under the action of the developer. The subject of the picture shows at fir^i as a white -ilhouette; for instance, if it is a hand it shows merely the white hand without any indication of the' bones. As the 1 devel- opment progresses the portion of the plate affected by the .r-ray. which ha- passed through the soft parts darkens up somewhat and we 1 have three general shades; the' comparat ive whiteness of the 1 bones, e)r any t'oreiun body, the moderate darkness of the' flesh, and the 1 blackness of the bare portion of the plate. The bare portion of the 1 plate 1 in- rreases in opacity, while- the- part ce>ve-red by the object remains trans- lucent. The iinau'e. t heivfore, is visible by transmitted as we'll as reflected htrht. Figure .">.">;$ shows the 1 appearane-e- of a plate after (level- THE X-RAY 875 opniont and Fig. 554 after fixing. The latter process dissolves out the unchanged silver salt and makes the plate lose its dead white appearance and become perfectly transparent at the places where the tissues were densest and the plate was least affected by the x-ray. Fig. 555 is the radiograph whose development has been depicted in the previous figure. It would have been better for longer devel- opment. It is a fatal error to stop the development too soon. In that case you have a thin plate possibly with plenty of detail, but one from which it is impossible to make a good print. As the development proceeds the portions of the plate which represent the shadow of the Mesh and bones become darker, and the image appears to be fading out. "j'~)4. Plato after development and fixation. The " hypo " has removed every trace of niilkiness and the thinner parts are transparent. This is very apt to frighten the beginner, but it is just exactly what should happen; if the development is stopped before the bones have darkened to sonic extent the resulting picture will give merely a silhou- ette of the bones without the structural detail which the best x-ray work should show. Even if the image disappears entirely and the plate appears entirely black the picture of the bones is still there and, perhaps, with more detail than could have been obtained with a shorter develop- ment. In a general way, anything that appears fairly white on the plate at the end of development will be absolutely transparent on the finished plate and quite black on the print, if the remainder of the plate has good density. The ideal x-ray picture is one in which the lights are white and the shadows black. To accomplish this the tube must have ^rfh MKD1CAL KI.KCTHiriTY AND KONTliKX KAYS the right degree of vacuum and must give a sufficient intensity and have a degree of penetration which passes through the soft pai'ts, but casts a deep shadow of the bones, and, of course, the exposure to the .r-ray must be of sufficient duration, (liven these coin lit ions, the development should be carried on until the darker parts of the plate are opaque to transmitted light and. therefore, have the requisite density, but should usually not be carried far enough to completely wipe out 1 he visible image P 4 ? on the plate. Determining the density of flu- plate by holding it up i'ii the operator ;ind the liulii and looking ;,t il b\- transmitted le \\ it h .r-rn v pi a 1 <-. \\'hi' j li a re a t'fect ei 1 1 >v expo- lire to ^hoi'l i |e\'elopnient i< required to -ho\\' the soft pai'ts - \\cll as the bones. I he lotmc-t development is md peh'is and hip-joint. :md in 1 he>e ca.-es the : on the plate a- to -ho\v practically wliile ' vords. \\ it h a pelvic pict ure -ome p;i rl s of 1 he Tin-; .r-K.\Y 877 plate have boon very slightly acted upon by the a;-rav, which has had to penetrate (i or S inches or more of flesh and bone, whereas other parts have 1 received the direct rays from the tube 1 , or rays only slightly impeded by passing through an inch or t \vo of fle'sh at the outer limits of the body. During the full development reeiuircd lo bring into view the faint image impressed by the denser parts of the body, the other portions of the plate- darken up by rece'iving what -amounts to over- development, and thus, in the finished picture of the hip-joint, for example 1 , t he flesh forms a slight ly s ha < led part of the; gone-ral background. 'Die real picture 1 in this particular case' is formed of the bones alone. .c-Ray films up to S x 10 inches are easily developed in a flat tray by clamping the' author's film clip to one e'nd. And two S x 10 films, either single e>r elupliti/od, can be developed in the same 1 S x 10 tray. Fhe clips are to be; at opposite 1 ends and the 1 se-cond film must be 1 thor- oughly wet in water be-fore- it is put in the 1 developer, so as not to stick to the 1 first one 1 . Frequent changes are made by pulling out the one underneath ami placing it on top. Large 1 !' films or a larger number to be 1 dovolopoel are betteT handled in suitable clip frame's which enable the-m to be 1 hung vertically in a tank. E.i'U'id lo Which Development Should l>c Carried. Xo certain number of minutes may be usually elepe'nde-d upon, either for tray-development with a strong devele)por or for lemg, weak tank dove'le)pment. Differ- ences in exposure necessitate variations in the 1 time 1 of development, and, generally speaking, the most satisfactory plates of films are those 1 whie-h are 1 fully developed in five or ten minute's in a strong developer or from one'-half to two hours with tank development. De'ntal radiographs upon positive cinematograph film should lie' de 1 - ve-lopenl until the image 1 is clearly visible upon the back of the film, and has begun to fade upon the 1 front it is nee-ossary that details should bo seen. The cardinal principle is that where 1 the plate 1 remains perfe'ctly white no details will be 1 founel, nothing but total transparency, that wheMv the plate' is moderately elarkonod oveTy detail will be visible 1 , and whore the plate 1 is black the density will be so great that the plate is opaque and details are lost. The latteT condition i< commonly seen upon the 1 portion of the plate 1 outsiele the 1 image of the patient. The next part of the process consist> in "jiritn/'' the image on the plate. This is done by soaking th" plate in an for about half an hour: until five minute's after all have disappeared from the film. following washed in runnniL!; water for about an hour chemicals, especially 'he hypo, which would c< S7S MKIMfAL KLKCTHHTrV AM) HoXTCKX RAYS which prevents softening or frilling of the film during the subsequent washing. This can he used several times, adding hyposulphite of sodium to it when it becomes exhausted. The plate should be carefully washed off, using the finger-tips or a verv soft sponge to remove particles of sediment from the film surface, and real rubbing to remove a tough black film which is found in spots near the edires of the glass or back surface. Then the plate is set in a drying rack in a place where dust will not be likely to catch upon the moist gelatin surface of the film. If a koiluf: or similar celluloid film is used the process of development is the same, but at the end a counle of pins are stuck through the corners and the film hung up to dry. In any ca.-e the r.ra.v.s- of moisture had better be wiped off before the film surface has begun to dry. Tear drops on the plate and a line of water at the bottom of the plate make the film dry more slowly and rau.-e darker areas in those places. The chemistry of photography is interesting. The dry plates or celluloid films are coated with a gelatin or other emulsion containing nitrate and bromid of silver, and when this is acted upon by light the .-ilver compounds become more easily acted upon by agents which seek oxygen. The developing solutions contain such agents and on the portions of the plate acted upon by light metallic silver is deposited by the abstraction of oxygen from the original chemic compounds. This produces a visible image, whereas none was to be seen when the plate was first looked at in the dark room after exposure either to light or to the .r-ray. But this image has to be made permanent by the process of fixing, which consists in soaking in a solution containing hyposulphite of sodium; this dissolves away all the unchanged silver compounds. The choice of developers is important. The old standard developing agent is pyrogallic acid, and probably one can make a greater number of good plates with all sorts of normal or under- or overexposures by its tise than with any other. It makes a brownish colored plate which prints better than the black or gray plates produced by most other developers. About the only objections to it are the facts that it stains the hands badly and that it cannot be used for developing the print also. A good formula for a pi/ro dcrcloptr is Water Ifi ounces Pvroirallic ncid 1 ounce Ox'dic arii 1 1 grains Water ](') ounces I)ri' j il sulphite of sodium ,, .. \Vat.-r. . . Hi ounces I tried carbonate of sodium 2 Use Solution A, 1 ox.; Solution B.I ox.; Solution (', 1 ox.; water, 7 ox. I)evlopini: factor 12. By " ili i-ilo/n'/n/ fat-tor J,.'" we mean that if we note the time from placing the phite in the developer until the appearance of the image and multiply that time by 12 we shall have the time required for complete development. With this developer a normal exposure will .-how an linage in twenty to forty seconds and, consequently, only two to four minutes' development would be required. If an image (Iocs not show at all after a minute or so the plate has been underexposed, and THK .C-KAY S70 it may be wise to pour off the developer and treat the plate as we would have if we had known beforehand that it was underexposed. For a known underexposure an excellent way is to use the soda solution alone at first: Solution H. 1 ox;.; solution (', 1 ox.; water, 7 07,.; allow the plate to remain in this for about half an hour, then pour the solution off and add to it solution A, 1 ox.., and use the complete mixture for ten minutes. At first an image becomes visible from the action of the soda solution, but it is faint and soon disappears, the entire plate blackening up. During the rest of the process the plate is just black all over and it is not until after it is removed from the hypo, and can be examined by looking through the plate in ordinary daylight, that the image can be seen. It may then be found to be very good indeed and may make an excellent print. Generally speaking, the pyro makes density and the soda detail, and if the complete developer were used for the length of time required to produce a good image with underexposure the pyro would make the plate too dense all over or fog it. The term fone very good guide in developing all single-coated plates ami films i- fhe presence of an image on the back of the plate. This usually .-hows complete development. Tank Developing. A good formula for this purpose i- the following: Stork Snlutntt, Water ( ';ir! )' unif i if si ii ii'liii 'irii-'i; S'll) 'iiitr of soi iililll :}' usi m developing a number of s Pi-inch plates take o/. oi i hi.- -lock solution and 10 pints of water, fillmtr' the tank. i: : rse tlie plates HI cool water before putting them m the tank. the] ij nek up-and-down moiion .'.','< i placing m ihe lank to : bells. Take them out of the tank after a few minute- and ' fii'-n po.-ition; thi.- i- to prevent streak- from the solution beinir po--ibl\- -i ron tier at 1 he bo t torn of the tank. ( tccasionallv rock- 'nitr : ' i- of u'reat service in preventing spot- and -ti'eaks. Si '. ral plate- of the same or of dilVeretit si/e- ma\" be develoJK'd in I hi lank al the same time. A cover i- placed over it. -o that the ii kept dark diiriuti the entire time, but only from time '-' ' e i : more ot the plate- are ready to be taken Ironi the ' : ; 1 1 placed in the hy | K i. I ' . ' t ho o _ l\ in tank developn lent lor instant a neons exposures 1 - t he plate may be de.-cribed a- underexjio-cd and rable number o| plate- are to be developed on the . I >' fur /"/////*.- Kadi film maybe fastened by ciani]).- a '.'.Me frame. 'I he him- are put m a rack and im- mer-i ;,, \\et i he films thoroughly and then set in the di vi . ,,. of developer. Thi- mu-t all be done in the dark SSI room by red lijiht, bu'i alter the cover has been put on the t;ink the operator may open the dark room and then leave the films for about the time required for normal exposures if one is sure of uniformity as to the exposure. The fixing takes about fifteen minutes and then water may be allowed to run through the tank for half an hour. This removes the hypo from both the films and the tank. A nickel-plated tank may be used for all three of these processes, whereas a zinc tank could not be used for the hypo; this solution acts upon zinc. witse Compartments iSmches land, inside Fij:. o.~>7. Paragon stone developing tank. (Gen. \Y. Brady iV Co., Chicago.) "All tank developers which are to be kept for any length of time must be covered, to prevent oxidation, either with a floating lid or a piece of paraffin paper cut to the exact size of the tank and floated on the solution.'' (Kastman Kodak Co.). The M. Q. Developer. The inetol hydroqtiinone developer has conn- into verv genera! use for developing dry plates ami celluloid films and also for velox and bromid paper and similar print-. Jt is easy tn handle, does not stain ihe finders badly, and jjjves a clear black plate whirh is very hand-ome and which has almost as uood printing qualities, as one developed by pyro. Its disadvantages are i he slowness with which i' acts, and the ji'nui.ter difficulty of exactly regul at ing the develoj)- nicnl to tret the best results out of different plate.- with all sorts of exposures. It is stild everywhere in tubes, each or 10 drops of a 10 per cent, solution of bromid of potash as a restrainer, or else pour off the developer and use an old and partly exhausted developer. If no i ma ire is visible in five or ten minutes the plate lias been underexposed and is iroiim 1 to require prolonged development in a weakened developer. An ordinary hip-joint picture requires about, one hour'.- development in M . (.,). developer \\hich is not entirely new. A picture o| the Toot would require about halt an hour's development. Mo-; of the radiographs in t his book were developed with M. ( ). developer in a simple ilat tray, and probably it will be found be-t to use this as ;i starting point, and then to add the tank development and th<' soda followed by pyro development as one's ireneral technic improves. 882 MEDICAL ELECTRICITY AND RONTGEN RAYS Other good developers are: Kiknnoqen-hydroquinone A. Water 4S oxincos Sulphite nf sniliuin dried) 2 F.ikoiio ounces; li, 1 ounce. Factor 12. Ortol A. Water 24 ounces Potassium metabisulphite 00 Drains Ortol 1X0 " I'se e(|ual parts of A and B. Factor 11. These are practically the same as recommended by the M. A. Seed Dry Plate Company, Si. Louis. Missouri. The special advantage claimed for pyrocatechin is that it can be used in cases requiring prolonged development without fogging the plate. Eastman x-ray developing powders are a groat convenience. They have -imply to be dissolved in water and have much the same properties as metal hydrochinon. A developer containing only hydrochinon as its active 1 agent quickly affects the surface, and with it the striking through of the image should not be wailed for. but simply the density. Such a developer may be cheaply and desirably made bv using 1 ounce of caustic soda to each Ballon of developer as a substitute for the carbonate of potash called for by most formula 1 . With this developer very little loss of density occurs in fixing. The Titubator. This is a useful apparatus in which the plate in a tray lull of developer is placed in a light-proof box and by an electric motor i.- subjected to the gentle rocking required. The plate must be placed in the titubator in the dark room, but the tlurtv minutes or ,-o of locking IJKIV be done by the closed machine in anv ordinary light. The Influence of the ./--Ray Upon Plates During Development. 'I lie r-ray .-hould not be m ope rat ion in t he .-a me room or in an adjoining loom. An ordmarv lath and plaster partition is perfectly transparent io the .r-ray and during the prolonged development , so often required ./-ray plates, they would be sure to be fogged. The same is true eve] .; iho plates ;iro 111 sheet iron (galvanized or tinned or japanned) , but ,i the developing t rays, are com j) let eiy .-ur rounded by a box of r-ray mHid. lead and tin. the plates are .-nfo. The protection should be ;,! top, bottom, and -ides.; but. of course, it is understood that even THE 3XRAY 883 with tliis it would not do to allow the x-ray to shine directly upon it at short range. Making Prints from x-Ray Plates. The print is the finished pic- ture on paper. It is made by placing the film side of the paper in contact with the film side of the plate, allowing ordinary light to shine through the plate, the varying density of different parts of the plate producing the lights and shadows of the picture on the sensitized sur- face of the paper. In the case of Solio and other printing-out paper the image is visible upon the paper before any further treatment is given to it, and the printing, or exposure to light, is continued until the print is dark enough. The printing frame opens in sections, so that one part of the print may be inspected from time to time without disturbing the relative position of the paper and the plate; just like opening a book and closing it again. These papers require brilliant daylight and take from a few seconds to half an hour or more to print, depending upon the density of the plate. They may be made by the electric arc light, but not bv the incandescent light. The print should bo made several shades darker than vou wish it to finallv appeal 1 , as it fades to some extent in the different solutions. It is first washed in five or six chang< of water to remove t he unchanged silver and then placed in the Bicarbonate of sodium sufficient to produce a neutral reliction The print should tone in about six or seven minutes, during which time a cheinic change lakes place in the film whereby a deposit of metallic irold takes the place of the silver compound on the surface ot the paper. At the same time the color of the picture changes from 884 reddish to a rich purplish In-own. Failure to produce this change in color would indicate a worthless toning solution. The print is then washed in water and placet 1 for twenty minutes in the acid hypo, where the image is made permanent and the film hardened. The formula for this is almost the same as the one recom- mended ft a 1 fixing ] ilates. Ariii If.'//"' /or >// Print* Hyposulphite of sodium (i ounces Alum crystals _", Sulphite oi' -odium crystals! . . ^ ounce Water .^ . 7(1 ounces. All traces of the hypo should be removed by washing for an hour in runnim: water. Print* M'ldcfrnm Pluto* or Film* 1T///V/, Art N/ '// ir ( /._i t isoccasion- ally desirable to obtain a print at once without waiting for hours while the plate or film dries. While the sensitized surface is still perfectly wet a sheet of photographic paper, also wet, is laid upon it. The two sen- sitized surface^ are face to face and gentle pressure i- made to squeeze out any bubbles of air which may be trapped between them. The print is made in the usual manner, but is not quite so clear as if made with dry paper and a dried film or plate. The plate or film is not injured if this is carefully done. In niftuntiiifi print* on cardboard the first thinir is to dry the prints nnd trim them, then wet them and pile them one rni top of the other face down on a sheet of glass. Squeeze out the excess of \vater by means of a piece of blotting-paper and a print roller. Cover the back of the Topmost print with photo paste, lift up the print by two opposite corners, and phu-e it in position upon the card and rub it down smoothly with th" print roller. Yelox paper and other similar papers require only a few seconds' exposure' to gas or electric lidit at a distance equal to one and a half tun"- the diagonal measurement of the plate. \o image is perceptible (111! I the paper has been placed m the developer and. hence these are . 'ofii nij-r>iit papers. The M. Q. devi !oper used for developing ; . . ., excellent i'e-i ; ' - "with the.-e pa ]i"'.> . 'id i he same acid hvpo . ion may be used. It! USUIL; i li.- 1 papers i! i- necessary to . - ': .! with - 1 !!'- of paper \\\\ me of exposure to be !. the i \posure i- too long the paper blacken- u]i in the devel- e! ail i llie ] lid lire is lost . [f the t posiire i- too sh< H't no : ie in the ' leveloj iel' will ] i!'< idlice a '^ M >< 1 1 il'illt . handled in i he sa me \' a v as \ !( ix. but ai'e mu"h e:.-i in a: 1, hence print in a much shorter tune of exposure. in making prim 'TV large ] ila les 1 iccause ; gradually vvlule the\ are m i he developer, more . I of flashin . e like the image on ! ' i -. I lie! et'i ,1-f. easier to - U e a perfect print . : ' - it i- liece--, ollli'lllv before 1 and then to set i hai 1 he d< velo] .< r iiist an! ly <<, i- - all | tail - of the prii ! , ot hel V\ ise the pl'ilit Will ii' darker or linhier coloi shoeing uneven 1UU.-1 be iaken oul oj I he ie\ e]o| ier at jllst ! 1 inn -lioui 1 In I'll ed ni wal er belol'o SS5 placing in llic acid hypo. The paper should not he creased and crum- pled, as this will he sure to cause a separation of the sensitive film or coating and the formation of blisters. These also result from letting a st ream of water st r ike directly on t he film surface and. especiallv, from putting the print into water or solutions which present too great a difference of tempera! ure. The process of making and developing all except hromid prints may he carried on hy ordinary light in quite a darkened room. In making a print from ti lunji /tlti/r it will sometimes happen that one part o| the plate is thinner and prints more rapidly than another, and in such a case the thinner part should he held further from the light or else covered up during part of the exposure. If covered it must he by some object which is kept in constant motion to prevent a line of demarcat ion. 1'i'i nlinij from a Thin Plate. Where the details in a thin and almost transparent part of the plate are desired the print should be a light one. The ordinary length of exposure to light in making the print would make all this part simply a black mass. Ili'iimiil Print* Directly from the Patient.- P>y this method a finished paper print is made inside of five minutes. One or more sheets of bromid paper are placed inside a light-proof envelope and u>ed exactly like a plat ! in taking an .r-ray picture. The paper is, developed just like an ordinary bromid print, but shows the bones white, the ilesh whitish, and the background gray or black. 'The process is one that does not require a dark room and saves a very great deal of time. You get a print in five minutes as against about twenty-four hours by the plate method. This is much sooner than even a wet and only partially finished plate would be read}' for examination. It is useful, for instance, in examinations for a needle in the 1 hand or for a fracture about the hand. In these cases a fluoroscopic examination often fails while the picture succeeds. Then again, the picture can be examined and discussed ad libitum, whereas a con.-ultation while examining with the .r-ray is a source of very great danger from too long exposure. With a Ii2-inch in- duction-coil and a primary current of !^ amperes (intensity Xo. 15 Tousey, penetration Xo. (> Benoist), a picture of the hand by this method would require an exposure of about twenty-live seconds. Such a picture taken at a meeting of the .Middlesex County Medical Society of Xew Jersey showed the barb of a fish hook which had been in a doctor'.; finger for thirty years. 'The method is especially available for the extremities and for dental skiagraphy. The best, result- are obtained with exposures two or three times as long as are required for a plate, and this makes it less useful for the thicker portions of the body. Plastic radiographs are prints to which an artificial appearance of perspective is given. A process was suggested by Alexander and perfected by Schellenberg. It consists, essentially, in making a radio- graph upon a single photographic plate, then making a print from this on a transparent film. The finished print is made from both plate and the transparent positive film, placed one on top of the other, but not exactly coincident. A very simple and easy process is to use what is technically called bromid imjntirc pn/xr for the first positive print from the original plate. This paper, after development . is rendered trans- parent bv i m niers ion in an oil v substance, and can t hen he laid upon the SM> MKDICAL KLK< TKICITY AND RONTGEN RAYS original plate and a print ran bo made upon any ordinary volox or solio papers. Such pictures iu:iy have 1 cortain usos, hut they do not give any true 1 stereoscopic effort. Alexander's Ml:i)'-t 1 kiv. OrVdX'jryi-sUli't, I'.HII'i. etc. 2 Minich. M.'-l. \\och., July :',!, I'.XWi. THE X-RAY 887 which will spoil the whole work. Eternal vigilance must be used with" this and all the other chemicals. There must be a special tray for the hyposulphite of sodium solution and when through with it the solution must be filtered back into its own bottle. Running water should be constantly ready and the fingers should be washed every time they have been in any of the chemicals. Keep up a rocking motion of the trays in which plates or films are being developed. Do not let one lie on top of another, as that would scratch it or prevent the uniform action of the developer on all parts of it. From beginning to end the plates and celluloid films ought never to see a particle of white light or of .r-ray except during the actual taking of the picture. They ought to be exposed .just as little as possible to ruby light in the processes of placing them in the opaque envelopes and later placing them in the developer. While in the developer they ought to be in absolute darkness, except for occasional examination by the ruby light to note the progress of development. A very important point is not to touch the film surface during the different manipulations. A touch with the finger is apt to leave an "opaque finger mark" on the plate which ruins that particular part of it. This would show in the print as a white smudge. ( lencrally speaking, if a beginner watches the development of a plate he is apt to underdevelop it; fearful of losing the image altogether when he sees it begin to fade out upon the surface of the plate. This fading simply means that that portion of the plate also is beginning to be developed as well as the background which was directly exposed to the .r-ray. Tf this is stopped much too soon, of course, you fail to get any detail in the picture, and may hardly see the bones in the flat appearing image of the flesh. If the development is stopped only a little too soon you may get a plate with good detail, but so thin and transparent that it makes a very faint print. On the other hand, a little overdevelopment does no harm at all, it simply means that you have to hold the finished plate up toward a bright light to see the image, the print made from it is perfect. A plate very much overdeveloped is almost jet black and opaque, and must be held up to a very powerful light, like the Cooper Hewitt light, in order to seethe image; and a print from it shows only th,e bones. The flesh and even thinner portions of bone may not show at all in a print from such a plate. The print is also a harsh black and white. Restraining the Development. A plate on which the image flashes up almost immediately when it is put in the developer has usually Ixvn overexposed, and if developed in the ordinary way soon turns black and will be so dense that the picture can hardly be seen at all. Such a plate would take a very long time to make even a poor print from; and it could not be studied by transmitted light unless one had a very powerful electric lamp. One may know from the length and strength of exposure to the .r-ray that the plate is overexposed. In case this fact is only discovered when developing the plate the latter may be quickly transferred to plain water and then developed in an old developer weakened by previous use, or in a developer weakened by dilution with water. Another method is to quickly add '' Hestrainer" to the developer. Tin; restrainer is a few drops of a 10 per cent, solution of bromid of potassium. MKDICAI. KI.K(TKIC!TY AM) HOXTCEN !;AYS Hie (ilijcct in restraining the development of a plate is to obtain sufficient detail without excessive density. The details depend Upon slight differences in densitv which call onlv he brought out by .-lo\V ' [eVelo] illlelit alld llloi lel'ate . lellsitV. A plate \\hich is known to he overexposed is developed from the start in i >ld or dilute developer or one to which rest rai ner has heen added. Overexposed Plates Which Should Not Be Restrained. liadio- Liraph.s (it th" head, abdomen, or hip are usuallv overe\j)osed at il^e-. where the .''-ray shines directly on the plate, but 1 he central nt part of the plate is underexposed rather than development should not be restrained, but the loss dges. o[ thf p let lire should be accepted as a necessarv ases the oveivxposure at the edges is -o great as almost t!r n hyilr'ifhinnn. 1 .Ir i 1) - ounces of di-till;-'! water, hot; then add to the sodas. We -olution; u.-c full -trcnuth aiti-r coolniir. d und< rexpo-ure requires long and s|< ,\\ development in a weak flev'i ntil the dei;iil~ are brought out and then forcing. Tank ';<>:!< nt in tin- ca.se. and so i- the process bv which the pla'e efserl in the -odium -ulphite solution for several minutes THE .r-RAY 880 nnd then in the pyro solution. In spite of all this manipulation the finished plate may he found too thin or the image too faint : and intensi- fieat ion may he resorted to. Development of Screen Plates.- Radiographs made with an intensi- fying screen are more like ordinary photographs, and a special develop- in. u' formula is given on page SOS. Intensifying x-Ray Negatives.- This process may he applied to a plate or film at any time after complete development and either hefore or after drying. The usual method is to immerse the plate in an inten- sifying solution, such as 220 grains until the entire plate has turned white, and the picture shows upon it like a positive. The longer the plate is left in the intensifier the denser l he negat ive will be. The next step is to wash the plate in running water for about half an hour. Then the plate is immersed in ilpl'iiir - . 1 ?, ounces Until it has all turned perfectly black. A final washing in running water completes the process. Yellow stains indicate incomplete washing after the mercury bichlo- rid bath. The process of intensifying gives added density to every part of the plate in proportion to its original density. This increases the contrast between the parts but slightly affected by the .r-ray and the other parts which are decidedly affected. Intensification is a perfect!}" legitimate expedient, but it has not been adopted in making any of .the radiographs in the present volume, and the author always tries to avoid the necessity for it by employing an exposure which will give a good picture with normal or somewhat forced development. It is useful for underexposed negatives and also for certain over- exposed negatives. In the latter case the plate lias sometimes been kept from becoming too dense by the use of restrainer or very careful development; but still a print from it presents scarcely any contrast. This defect may sometimes be remedied by intensification of the finished negative. The results are very much better if the exposure can be so regulated that normal development suffices. The Choice of Developers. As a general thing there is very much to be gained by using the developing formula recommended by the manufacturer of the plate or film. An example of this fact was lately brought to the author's attention. A friend had been using a certain film on his, recommendation and with excellent results. After about a year the quality of the pictures suddenly underwent a radical change. The same subjects that formerly required an exposure of ten seconds now required forty seconds, and the pictures were lacking in brilliancy 800 MEDICAL KLKCTKICITY AND KONTCEN RAYS and contrast. After considerable correspondence with the company, it transpired that they were using a new emulsion on these films and that they recommended a different developer from the one that he had l>een using. The moment that the right developer was used the results became as good as wiili tin 1 old films. Development in Tropical Countries. The difficulty is almost en- tirely a matter of temperature, the atmospheric humidity not having much (if a disturbing effect except in making the plates and films dry very slowly. The usual developing solutions must be used at a tem- perature of about t).~) F. and can only be used if ice is available. Where it i- impracticable to keep the solution at about this temperature means must be adopted to harden the sensiti/ed coating of the film or plate. This is done by immersion in a solution of formalin. The developer must also be somewhat different from the normal one. HO parts 1 part for about three minutes, rocking the tray occasionally, then rinse well and place in the developer. If the image flashes up in less than forty seconds add more of the potassium brotuid. Development should be complete in four minutes if the exposun- has been normal. The Explanation of Some Defects in Developed Plates. Some- time- the i'il m /x ir/isfml o//"the plate, leaving perfectly clear glass at the edires. -hading gradually into the pictured part of the plate. This is apt to occur with a developer that is a little too warm if the plate has to be left in it for a long time and has to In- handled much. Carried to an extreme, the whole picture would be washed oft the plate. Tin- sensitized coating of the plate may be full of r/v/rA-.s- running in every direction and dividing the surface into numerous sections. This lion i- usually due io t he use of t oo warm solut ions for developing, :. ..._. or \va-himr t he plat e. There may t>e a general n/n/>!i/ii/.c i- only used i'oi 1 ihc largest portion-^ of ! he bodv and s prole i] el'ipi cut. li is unwise, t hcri fore, to use one for this purpose 1 if it I- more than t \vo months old. The plate, however, may he nil up Hit 1 1 smaller sixes and used for ra< ho i:Ta | hs of the exl remi- ties. [ would no! he wise 1o try to make a frontal .-inns picture on a piece nit from such a plate because the same conditions prevail here as i:i ' i 1 abdomen. '/i/iir /Y>//r.s-. This is done by drawing a line on the irlass not the film airface with a glass cutter and i hen bending it away from the scratched surface. This can be readily done before the plate has been developetl; but i he latter process makes the film so dense and tough that one is very likely to break the plan into several pieces, instead of breaking it along a straight line. Still it sometimes happens that 'lure is just a small part of a larue developed plate which one \vi.-heS to cut o:;t . 'I'o tt (i hed plate and any prim- made from it. There is only to prevent this accident and thai is not to touch the sensitixed - irface rt'itli any hai'd substance until after it has been developed and ["he finished plate is quite durable and will siand any ordinary ',vj.. but if it is to be used a number of t hues for purposes of demon- s'ra'ion i' had better be protected by varnish. Varnishing the Plate. A varnish is made for this purpose which dries dear and hard. The plate is he-Id honxont a lly in one- hand while.' ounce or more of varnish is poured over it. Tins is allowed to over d iff' t 1 ' -Jit parts of the plate unt il t he <'iit ire film surface has been . ' and th'-n it is drained back into the bottle. The' plate is stood up ; to dry in a place \vhicli is free from dust. Perspiration-marks on the Plate.- The ordinary envelope in tes arc. 1 useel is perfectly permeable to moisture', and the triko through from any part of ihe bodv which lies ion i;. Th ( : chemic properties of the perspiration cause it .. . ' effect upon the !ili!i. ;.nd this is sho\\ n as a spots on the fini.-hed plate, or \\hite spots on the es it an invariable ciisiom to lay a piece of : or cardboard under the part thai rests upon the > TIII-: .T-RAY The envelopes which contain the plates may produce an injurious effect upon the sensitized surface. Ordinary paper contains so much sulphur that it is entirely unsuited for this purpose and even tin- specially prepared envelopes are not entirely safe. To be absolutely secure against trouble from this source the plates should be kept in the original boxes until just before use, and then should be put in the opaque envelopes in the dark room. I'sually, however, the envelopes are safe enough for .several weeks, except for some case which result.- in underexposure and prolonged development; then the slight harmful effect upon the plate may be brought out and may entirely overshadow the picture. The -paste which is used to fasten the seams of the envelope has an especially deleterious effect upon the photographic plate, and the plate should always be put in the envelopes so that the smooth side of both envelopes is at the film side of the plate. The author almost always exposes two plates at the sam" time, so as to have one to send to the physician and one to retain as a record. Trouble due to the effect of the envelopes upon the film can be avoided by keeping two plates face to face in the same envelope, being careful nut to produce the scratch-marks referred to above. Sulphur and moisture affect photographic films very badly and plates must be carefully protected from both of these. The amount of sulphur present in the air of ordinary dwellings, especially if lighted by gas, is shown by the quickness with which silver tarnishes. Tin- sensi- tixed film is really an exquisitely susceptible silver surface. The same factors occasionally damage the plates and films which are sent across the At lant ic Ocean. Fogging from ,r-Ray in the Place in Which the Plates are Stored. The plates should be stored in another room and separated by a bi'ick wall from the .r-ray tube. Kven then they should not be kept on an ordinary shelf, but should be in a lead-lined box. and the cover of this should never bo left off when 1 he .r-ray is t urned on in an adjoining room. Ordinary light diffuses into an adjoining room through an open door even if a screen is placed to cut off the direct rays from the lamp; and in just the same way secondary rays arise from every object in the .r-rav room and any adjoining room not separated by an impenetrable pail it ion such as a bi'ick wall. Tin' danger of ruining plates O r films, which may represent several dollar-' worth of material or several hours oi labor, by a few seconds' exposure to the .r-ray is something that -hould be constantly borne in mind. It is an excellent rule ne\er to bring an undeveloped plate or film into the .r-ray room at any time except when that special plate i- to be exposed for a radiograph. Another u-ood rule is to have the cover of ! he lead-lined box for plate.- and films made in such a way t hat the cover cannot be taken off entirely, and thai it will shut of it- own weight except when held open by the hand. In this way the box can never be left open accidentally. The author uses a wash-boiler, measur- ing liXl">> -1 inches, for storinsj; unu>ed plates and film-. He lined t hi- himself with sheet -lead held in place by strips of adhesive plaster. Storage and Filing of Developed Plates and Films. The >/m/// film* on which tooth radiographs are made are marked with white ink after development, and all 1 he sin a II film- of each pat ieni are put in an envelope marked with the name <>i the patient and the examination r. Thus, the envelope mav be marked "Brown, lb:;:',; 1. i'. :!." MKIHCAL ELECTRICITY AND RONTGEN RAYS Those envelopes are all arranged in numerical order in a card index drawer, but there is also a card index of all patients' names from which the examination numlxT and the size of the plate or film can he learned in a moment. Each physician referring eases has a card in my card index giving the names of his different patients and their examination numbers. Lanjcr Jilni* up to 5X7 inches are stored in numerical order in a negative film file. The latter looks like a photograph album, but each leaf is made up of thin transparent paper forming a jxicket into which a film may be slipped. A hundred films filed in this way take up no more room than a l>ook measuring 5* X8*, inches and 1 inch thick. Films larger than 5X7 are kept in separate envelopes and filed in pigeon-holes. /'//< 'N for riah* Cp To and Induilintj 8X10 I nclicx. An excellent type of these is sold in America under the name of the- Star negative file Y\it. ")('>(). Star negative filo. 'Fig. .")('()). It is made for 5X7-, or (iJXN?.-, or SX 11-inch plates and consists of a box ( inches thick, and long and high enough for the proper sixe plate to tit in it in a vertical position between pasteboard partitions. The plaies require no envelopes and a notch at the top of each partition enables one to see the number marked on the plate in white ink. Jvich Hie holds 50 plates and when filled with the largest si/ed plates (NX 10 indies) it weighs only a little over 'JO pounds. The smaller ones weicji proportionately less. There is no difficulty, therefore, in lifting them off a close! shelf and carrying them to the light in order to find any particular plate, though it would be more convenient if one had a sale place to .-tore them where there was a good light. The same vertical Hies may be used for celluloid films and will hold three or loiir of these in each section. Sloriitfr ,if l-'inlxlinl I'lntc* Lnri/cr ffmn S -JO Inclicx.- The UX 17- inch plates, weii;h '.} pounds apiece and mav be stored in the heavy cardboard boxes in winch six of them are originallv sold. The number "I each of the six plates should be \\ritlen on the outside of the box, ,''!.'! the boxes -honld be stored vertically between wooden partitions about i 1 . inches apart. The wav which is adopted bv the author is to keep every plate larger than SX10 inches in a separate envelope, and to file the plates of each si/e together between vertical board partitions about f i inches a pa !'t . THE X-RAY 895 Largo films had bettor ho kopt in separate envelopes made for the purpose with a thin sheet of stiff cardboard and may then be placed in a port-folio, or filed between vertical partitions, or kept in a drawer. Their lightness and the fact that they cannot be broken makes films very much more convenient to preserve than glass plates. FLUOROSCOPY AND RADIOGRAPHY OF SPECIAL PARTS OF THE BODY The fluoroscope has a very definite field of usefulness; first, in determining the quality of the radiance, and second, in the examination of cases in which a glance tells the whole story. Time passes so rapidly when a patient is being examined and considered that the use of the fluoroscope may lead to a dangerous length of exposure. One case in point was communicated to me privately by an eminent physician in this city. A friend of his had some affection of the knee-joint for which a fluoroscopic examination was made and a consultation held, it being estimated afterward that the knee had been exposed to the x-ray for forty-five minutes. The result was a dermatitis followed by a pain- ful and intractable ulcer with such an effect upon the system at large that to save the man's life and reason an amputation was performed above the knee. Another case was reported by an excellent radiologist, Guilleminot, 1 who had been in the habit of removing foreign bodies from the hand under fluoroscopic observation. For instance, he would roughly locate a needle by means of the fluoroscope, take the patient into daylight and make an incision, then in the dark again guide the forceps, by means of the fluoroscopic image, until the needle was felt and seized. In the case reported the noodle could not be found, although two separate attempts were made four days apart. During these two seances the patient's hand and both the doctor's hands were actually exposed to the .r-ray for about thirty-five minutes. The distance from the tube was 3 or 4 inches, the vacuum was low. Although he does not give the strength of current used, it must have been considerable to enable the needle to be seen. The patient's hand and both the surgeon's hands developed a very severe dermatitis with alteration which took six months to heal completely and the skin was not absolutely sound at the end of a year. It does not follow that the fluoroscope should never lie used, but it is certainly very dangerous in a case where the image has to be studied for an uncertain length of time. (.\nlc. In the author's radiographic teclmic the spark length is measured be- tween moderately sharp points. It" measured between polished bulls his 4-inch spark should be 2.1 inches, and his o-ineh spark should be 4 inches.) 1 Archives D'Electricite Medicale, Bordeaux, France, Dec. 10, 1904. S'.lli THE AUTHOR'S TABLES OF RADIOGRAPHIC EXPOSURES Er.foeurefi for r. c t 1 lcgr-\phy of the Teeth. Th Slow Dental Films (Formerly called Eaatiran Positive Cinematograph Filitg.) A. For the expert Roentger.ologlPt . 13 Inches distance, 4 Inch spark 30 milll- airperee, 1/5 n-.llllir.eter aluirlnum filter. Jnl 1 Jrer. Vyrer Molara 6 - . Lower Uolare Bicuspids 5 sec. ;.cwer Ir.cir-cra Vrrer Incisors 4 so-. Adults ice t c 15C Us. r B ec, sec. 5 eec . 4 sec. 4 1/2 sec A ; J 1 1 J 10 sec. 6 sec . 6 r-ec. 5 S6C . 5 sec. E. For the Dentist. Inches distance, 6 Inch spark, 10 rilllaiperes . Children Upper l!olare 6 eec. Lower Molars 6 sec Eicusp ids 5 sec. Lcwer Incieore 3 eec. Upper InciBCrs 5 eec. Adults ICC to 15C Irs. 8 sec. 7 see . 6 sec. f t aec. 6 sec. Adults over 1C ibe. 10 sec. 8 aec. 7 pec. 5 aec . 7 eec. Bxposura Table for Radiography of the Head (except the teeth) and of the Seek. (Exposure in seconds, using Seed X Ray Plates or Eastman Duplltized X Ray FlEo Sei Female- Kale. eight, Ice. 20 40 90 ieo 160 200 : 50 110 i 140 180 220 t&ai, ar.taro- pcoterlcr, 5 ir.c.'i epir*. 2^ -A , Jr.tonsl- 4 4 I/? 5 6 6 1/2 e 4 4 I/? 6 6 1/f 7 3 l/ -jir.j screen, 1 .- ;;.es ar.ti- Ciitr.cde to plate -. ,-l"i , 1-1 t. -Til , -IT. 9 t-c:.r.ic. 8 S p. i/n 3 4 4 1/f r r l/r 3 4 4 1/2 5 Jaw , litor il u; r, -i- rr.al ; .at -3 ,L Ir.ch : \/7 3 4 4 1/3 : 3 4 4 1/J 5 6 p ; ^ .- K . I . r - t , :. , .. . ' /. , i"i" : i . . ' , ' . i , . ', ;, 10 i: li 1 . 12 14 15 :. .: v -'' 897 Exposure Table for Radiography of the tipper Extremity. Exposure In seconds, using Seed X Ray Plate or Eastman Duplltlzed X Ray Film, 23 Inches. Ho Intensifying Screen except when BO stated. Female. Vale. eight, Iks. 20 40 eo 120 160 200 20 50 110 140 180 2PO Shoulder. Plate behind. Tube near median line 4 5 8 10 12 15 4 5 % 9 IP 14 15 in front. 4 Inch spark. 30 ma. Shoulder. Plate in front. Tube behind, 10 inches 4 5 8 10 IP 15 4 5 /^ 9 12 14 15 from median line. Same technic. Shoulder. Plate in front , Tube 4 5 8 10 12 15 4 5 ; /7 9 12 14 15 near median line behind. 5 inch iimpl j to ehow upper part Of 1 imeru 3 in a pla ie at rlgh b spark, 30 ma, In- anftl 38 tO the other a to revef L dis ;lace nent n ca 30 Of tensifying screen. frac ture of th e nec[k of the 1- iroeru 3. Arm, Forearm and Elbow. 4 inch 2 '/! 3 4 5 6 8 2 /^ 3 4 6 7 8 spark, 30 ma. Wrist, antero-pce- terior prone, 4 2 2 Ib, 3 'A 4 5 6 2 2 T 4 6 8 inch spark, 30 ma. Wrist, lateral, 4 2 fa 3 5 fi % 7 '/ P '/* 3 4 5 7 #, 10 inch spark 30 ma. Hand, prone Fingers prone or one fin- 1 '/-, 2 * Z 4 4 'A 1 'h. 2 * 3 4 ^7 6 ger lateral, 4 Incl spark, 30 ma. Exposure lablo for Ribs, Lungs, Heart Aorta and Oesophagus; Also for Dorsal Vertetrae. Exposure In seconds using Seed X Ray Plata or Eastman Duplltlzed X Ray Film. Sex Female. Male. Weight, Ibs. 20 40 90 180 160 200 20 50 110 140 180 220 Ribs, lungs. heart, oesophag- us and aorta, Antero-posterior; i-late front or 4 6 8 10 1? 15 4 5t 10 13 15 13 back, 23 inches, 4 inch spark, 30 na . No screen. Ribs, lungs, heart, oeaophagus and aorta; lateral. . if Same teehnio but 4 5 8 10 12 15 4 5-4 10 13 15 19 with intensifying screen. Dorsal vertebrae, plate behind, 25 inches , 5 inch 4 5 8 10 12 15 4 5 10 13 16 18 spark, 30 ma. Dorsal vertebrae Lateral Same technic but with 4 5 8 10 12 15 4 5 % 9 12 14 15 intensifying screen. 898 MEDICAL ELECTRICITY AND KONTCEN HAYS Sex. Mile Exposure Table for Radiography of the Abdoiren prone upon the Piste. (Call-bladder, Pancreas, Empty Stomach and Intestine. ) And for Radiography Supine upon the plate with Compression (itidneye, tretere, Bladder, Lucbar Vertebrae and Felyis.) Also for the hip-Joint. Exposure A, Frcne Waist 26 27 S8 29 upcr. plale cr Supine *itr. ccnf-rosslcr.. Hips 32 54 3^ 55 34 36 35 38 Vertebrae requires Pcunde 113 110 120 11! 127 127 156 143 183 131 155 150 180 Exposure A 4 e 5 7 6 8 7 10 Child 28 Iba, 19 wala 2C hip, 2 1/2 sec. Exposure E 5 7 e e 8 12 Waist 2C 33 33 33 Exposure E, Is for tip- Joint prone or Kips J5 36 35 36 35 38 38 40 F curds 122 150 146 180 155 146 16C 146 170 All ar 3 inches, Seed X Say I late or Exposure A 1C 15 1C IP 11 13 11 14 Eaetiar Luplitlzed X r.aj Flic, 4. inch Exposure B 12 14 12 14 13 15 13 16 eparx, by preference, with Intensifying Kalst 54 35 36 37 ldit> . Cr inch spark without screen, Kl_B __ 3e 4C 26 4C 36 40 36 40 20 clillairperes. hip and waist circucfer- Founds 14C ISC 14S 150 1=C 135 165 180 156 180 ence In inches. Exposure in seconds. Expceurs A 12- 14 12 ie IE 18 13 19 Exposure E 14 ie 14 19 14 21 15 22 Saiat 38 39 40 41 :ips 37 4C 37 41 40 40 Founds 155 1P3 150 FCO 172 215 190 Exposure A 14 ?0 15 21 16 21 17 22 Exposure E 16 23 1R ?5 19 25 20 26 Walat 4F 43 44 45 Hips 40 40 41 42 Pcurds P06 232 FT; caure A 18 P3 IS 24 18 25 20 30 Exposure B 21 26 21 2B 21 29 23 35 _ . THE X-KAY 899 Exposure Table for Radiography of the Abdomen Prone. upon the Plate. (Gall-Bladder, Pancreas, Empty Stoirach and Intestines. ) Ana for Radiography Supine upon the plate with Compression (Kidneys, Ureters, Bladder Lumbar Vertebrae and Pelvis- j Also for the Hip-Joint Female. Exposure A, prone upon plate or supine with com- pression, (lateral of Lumbar Vertebrae Waist 22. 23 24 25 Kips 28 59 28 36 28 37 54 39 Pounds 85 100 95 117 IIS 68 103 95 142 86 119 145 ex; osure. ) Child 28 Ibs, IS waist, 20 hip, 2 1/2 'seconds, with this technic. Exposure B, IB for hip-Joint prone or BUI ine . All are 23 Inches, Seed X Ray Plate cr Eastman Duplitlzed X Kay Film, 4 inch ej.ark, by preferenc with intensifying screen of 2 1/2 rapidity. Or 5 Inch sparK without screen, 30 millian:- peree. Hip and waist circumference In Inches. Exposure in seconds. Exposure A 4 5 B 6 9 Exposure B 6 7 6 9 6 9 7 10 ^ Waist 6 27 28 29 Hips 35 39 36 42 35 42 36 40 Founds 110 lie 150 ICO 118 163 Ifl 137 i:*c iec IOC 138 138 180 Exposure A 6 9 8 9 8 10 8 10 Exposure B 7 10 9 10 9 12 9 12 Waist 30 31 32 33 Kips 36 43 39 43 36 44 36 44 _, Pounds li! MI 307 Ifl 180 Exposure A 9 10 9 13 10 14 10 14 Exposure B 10 12 10 14 12 16 12 16 Waist 34 35 36 37 Hips 36 44 36 44 39 47 38 47 ^ Pounds 136 180 136 180 150 195 150 195 Exposure A 10 16 12 18 14 14 22 Exposure B 12 18 14 21 16 24 16 26 Waist 38 39 Hips 39 47 39 47 Pourrte 170 200 170 COO Exposure A 16 24 20 24 Exposure B 19 . 28 24 28 900 MKIHCAL KLKCTKiriTY AND RONTGEN HAYS Exposure Table for Radiography of the Stomach and Intestines. (Exposure In seconds, using Seed and an Intensifying Screen of 2 Waist and hip circumference In X Ray Platee or Eaetraan- Duplitized X Ray Films 1/2 Rapidity. 6 inch spark, 50 irilllamperes. inches. ) Exposure A 23 inch- Waist 26 27 28 29 be. StGEach and Intee- hlpa 32 34 32 35 34 3 35 38 Pounds 115 110 N IT? 113 127 1P7 156 143 185 131 155 150 180 pTpoeure fc 18 or 19 Inches, Stomach Exponure A 2 2 2 5 2- 3 3 33- and Lucdenum. Exposure B l^ \ i i i r 2 1 ? 2 Z Exposure C 23 inch- Exposure C i i-i. It 2 it 2 li 2 es. Appendix with ectcpreeBion. Waist 30 31 52 33 Hipe 35 38 35 3P 35 38 36 40 Founds 122 155 146 IPO 155 146 IPO 146 170 Exposure A 3 4 St 4 Exposure B 2 3 2^ 3 3 3 3 3 i Exposure C 2 2 % 2 3 2 3 2t 3 Valet 34 35 36 37 Hips 36 40 36 40 36 40 36 40 Pounds 14C 180 142 150 IPO 135 165 180 156 180 Exposure A 4 4 4 C 4 5 4^ si- Exposure E 3 3 i 3 4 3 4 si 4-fc T Exposure C 1* *. 3 3 -fe * * s *-!: Waist JR 58 AO 4S Hlpe 37 40 37 40 40 40 Pounds 155 1"3 15C POO 172 215 190 Exposure A 4& 6 % 5 5i 5 6 5^; e Exposure B Zt 4i 4 4 V 4* A i 4^ 4-t Exposure C 3 3 3 4 3 4 4 4 Walet 4? 43 44 ^S Hips 40 40 41 42 Founds 26 232 Exprflure A 6 6 *, 6 7 6 7 6 7 Exposure E 4-2 5 44 5i 4 1 si; 4 -fc 5 sr Expoaure C 4 4 4 4 i 4 4 4S 5 THE 3>KAY 901 Expoaure Table for fiadiography of the Stoaach and Intestines Exposure In seconds, using Seed X Ray Platee or Eastman Duplltized X Ray Pllms and an Intensifying Screen of 8 1/2 Rapidity 5 inch spark. 30 mil llamperea. Waist and Hip circumference in Inches.) Female. Exposure A 23 inches Waist 22 23 24 25 Stomach and Intes- tines in general. Exposure E 18 or 19 inches. Stomach and Duodenum. Exposure C 23 inches Appendix with com- pression. Hips 28 39 28 36 28 37 34 39 Found D 55 100* 5 ii7 no 68 103 95 142 86 119 145 Exposure A 1 Z 1 3 2. 3 2 3 Exposure B I 2 1 2 1 2 2 3 Exposure C 1 I'-S 1 1 2 I'e- 8 Waist 26 27 28 29 Hips 35 39 35 42 36 42 36 42 Pounds 110 118 150 100 118 1S3 121 137 130 160 100 136 138 180 Exposure A 2 3 3 4 3 4 3 4 Exposure B 2 3 2 3 P 3 2- 3 Exposure C li z \r, ? 1 % 3 ? 2 Waist 50 31 22. 33 Hips 36 43 !9 43 36 44 36 44 Founds 134 163 141 107 160 121 160 130 180 7> S 4 5 4 5 Exposure E 3 3 3 4 3 4 3 4 Exposure C P 2 -Z 2 3 2 3 p-i si Waist 34 35 36 37 Kips 56 44 36 44 38 47 38 47 Founds 136 190 136 IPO 150 195 150 195 Exposure A 4 6 4 6 4 7 4 7 Exposure B 3 4 3 4 3 4 3 5 Exposure C P & 3-2 3 3 '* 4 4 $ 4 4 ^r Waist 38 39 Hips 39 47 39 47 Founds 170 POO 170 rco Exposure A 6 8 5 e Exposure 3 4 6 4 6 Exposure C 4 5 4 5 902 MEDICAL ELECTRICITY AND RONTGEN HAYS With t\vo thicknesses of tin to arrest secondary tissue rays and Kastman duplitixed iihn with t\vo intensifying screens, )>() milliamperes and ~>-inch spark, use the same number of seconds as in the exposure tables for the abdomen. Exposure Table for Radiography of the Lower Extremity. Exposure In seconds, using Seed X Ray Plate or Eastman Duplltlzed X R Film. 23 inches, 4 Inch spark, 30 mllliampereB. (N.t. The hip Joint ! given with the abdoalnal exposures.) Male. Weight, Ibs. ro 40 90 120 160 200 ro 50 110 140 180 PPO Thigh, lateral, or antero- 5 6 8 10 IS 14 6 8 1C 12 ir 14 poeter Icr . Knee, Leg. 2 -fe 3 4 5 6 7 3 4 6 6 6 7 Ankle, lateral. 2 fa t 4 5 e 7 3 4 5 6 6 7 Ankle, antero- poetericr . 3 4 5 6 7 9 4 5 6 7/k, 7 'A 9 Foot, prone. Toes, prone or 1 h 2 3 3 * 4 6 2 3 S f'i 4 4 5 one toe laterally THE HEAD Radiographs of the rrnnnun as distinguished from the face may be made on two different plans. One, which 1 designate as a marginal pit-lure, is occasionally useful when ihe portion to be studied is a part of the skull or. at all events, is near the surface. In such a case the head is to be placed upon the photographic plate in such a position that the shadow of the portion of interest will be at the margin of the general image of the head. If, for instance, it is about the forehead, the sagittal sut ure, or the occiput, the plate would be placed al t he side of 1 lie head; while tor a marginal picture of the temporal region the patient would lie with the plute under the back of his head. In the oilier, which I call the //r/i j>h of the cranium, the portion of interest is brought as close to the plate as possible and it- -hadow ii-ually falls at about the middle of tin 1 general image ft the cranium. For a direct radiograph of a tumor of the brain the plate would commonly be at the side of the head. A marginal radio- graph of the cranium should show both tables of the skull quite clearly. I-'rnrftirts <>i Ilir x/.-ull sometimes show very well in the marginal view \vi * h the fl Horoscope, us ( 1 () also depressions or thinning of t he skull from the pn-ss ure oi cysts and tumors, hut with the abnormal portion of th<- -kull in the centt r of the image, the change i.- mrelv visible with the fluoroscope. The radiograph, however, is extremely valuable. The cur- rent u.-'d for an induction-coil should be IS to 2"> amperes, and the tube should be 1 '> indies from t he skin to t he ant i cat h ode and should have a medium vacuum, resistance about i> inches, and penetration Xo. (i Benoi-t . A Iran-former, or an unfluctuating converter, would make the THE X-UAY 903 picture with 70 kilovolts and 30 to 50 milliamperes. The exposure with the eoil would be from fifteen to sixty seconds and with the more powerful apparatus one-fourth to one second. Tin; author's preference is for 5-inch spark, or (>5 kv., 30 inches distance, 30 ma., with intensifying screen, five seconds for 150-pound man (see Exposure Table, page 890) or any other 150 milliampere second exposure. In radiographing a case of fracture of the skull in profile the plate should be placed upon a pillow on the examining table beneath the patient's head, the anticathode being 30 inches above the plate. For a radiograph looking directly at the injured portion the tube may be at a distance of 30 inches from the plate, securing a picture of the entire head free from distortion, ")(51. Marginal radiograph of depressed fra< injury. if the skull, seven years after injured portion resting on the plate, resistance and exposure 'the same as for the marginal radiograph. Figure 5(>1 is a radiograph of such a case. The patient, a boy seven years of age, was beginning to lose his memory, possibly in consequence of an injury received when a baby. His father had thrown a saucer at the mother, but hit the baby's head, making a gutter-shaped depressed fracture which still shows in the radiograph. Radiographs proved of value in cases of "bursting fracture" of the skull, reported by Wight, 1 the profile as well as the direct view being successful. 1 Nc\v York Medical Journal, April 27, 1907. 004 MEDICAL ELECTRICITY AND RONTCJEN RAYS Differential Diagnosis Between Hematoma of the Scalp, Hernia Cerebri, and Fracture of the Skull. The author has several times successfully based this distinction upon the fluoroscopic appearance alone. The profile view of a hematoma shows the uniformly convex surface of the skull. The raised margin of the saucer-shaped depression is seen to be entirely transparent and superficial to the bone which takes 110 pan in its formation. Turning the head a little to one side or the other does not show any area of translucency in the bone. A direct view with the fluoroscope, that is, with the affected portion of the head nearest the lluoroscent screen, is not as conclusive as a radiograph made in this position. The radiograph showing a profile view gives the same results exactly as the fluoroscopic examination. A depressed fracture of the skull would be seen very easily with the fluoroscope in profile, but here again the radiograph would be necessary for a direct view. Making almost a profile radiograph, that is, with the head turned a little toward the plate, we vill get an image showing irregularity and some translucency, which, however, is very much less T han is the case in hernia cerebri, or in diseases characterized by the absence of bony tissue in a certain area. The last mentioned disease, hernia cerebri, presents a notched out- line when the skull is examined in profile by the x-ray ; and in a semi- profile view a very distinct circumscribed area of translucency. The latter is also shown very well in a direct view, but requires a radiograph. The strength of current, quality and intensity of the ray, and distance from the plate are the same as in other direct and marginal pictures of the head. Tumors of the Brain. Fluoroscopic examination is not to be recommended for a tumor of the brain. There always appears to be a denser urea in the part nearest the observer. Radiography of a brain tumor requires the same technic as in the profile radiograph of a frac- tured skull. Two pictures should be made, one with the plate behind tnd the tube directly in front at a distance of 30 inches from the plate, and the other from the same distance with the plate at the side of the head on which the tumor is supposed to be located. While many radiographs have been made which showed the presence of tumors of the brain, subsequently verified by operation, still such a radiograph i- not sufficiently clear to be accepted as anything more than corrobora- tive evidence. The radiographer is not the one to decide whether an operation H necessary or not. The w-titriclcx of flic lira in were shown to be full of air in a traumatic case radiographed by \V. II. Luckett' (Figs. f)(i2 and , : )i ;>). The diagnosis was confirmed by an autopsy. A'-ray Examinations for Foreign Bodies in the Cranial Cavity. - The exact locali/.at ion of a bullet or other foreign bodv will enabl" the -tirgeon to judge of tin- desirability of an operation for its removal. ; !io\ part of the head resting on it; the lube diamet ricall v \vill be better, however, ton-' 1 the author's lateral plate- f-ribcd on p. <)74. This enable.- one to make a preliminary examination and turn the patient's head into the position THE Z-KAY 905 at which the foreign body will be nearest the plate. It is very desirable to mark a small spot on the head with nitrate of silver just where the image of the foreign body is seen. This is done while looking through l-'ig. 562. Air in the ventricles of the brain. Lateral view. The arrows outline the distended ventricles. The large round white shadow is the right anterior horn (W. H. Luckett). the fluoroscope. A similar mark may be required in some cases at the opposite side of the head to indicate, the direction of the tube. Then FIJI. .">(>:>. Air in the ventricles of the brain. Anteroposterior view. Two lateral ventricles distended with air. Small round white shadow just between and below is th< third ventricle also distended with ai Arrows indicate the positions (\Y. II. Luckett). the plate in a stereoscopic holder is placed between the patient's head and the vertical board of the lateral plate-holder, and the radiograph is made. 90G MEDICAL KLE< TRieiTY AND RONTCKN KAYS St Localization. A single radiograph of a foreign body in the- cranium does not indicate the exact depth at which the body is located. Clear- ness and apparently natural size of the image indicate proximity to the plate; while vagueness and enlargement indicate that the foreign body is at a distance. In certain cases two separate radiographs may be made in directions almost at right angles with each other. The cranial landmarks shown in the radiographs may enable one to locate the foreign body ut the intersection of two definite lines. It is alwavs better, however, to mark both of these lines by two pairs of nitrate of silver stains applied under the guidance of the fluoroscope. The two radiographs at a right angle are not practicable or desirable in some locations in which a foreign bodv ma}' lie. In s;uch a case stereoscopic radiography may be useful. Strt'coxr'npir knil ini/ru phij of Foreign Bodtc* t// the Cranium. The. iscopic plate-holder may be flat upon the table with the patient's head resting upon it and tube above: or the author's lateral plate-holder may hold the stereoscopic plate-holder in a vertical position while the patient lies with the proper part of the head in contact with the plate-holder, and with the tube diametrically opposite. One radiograph is made with the tube in a certain position and then the plate is removed from the plate-holder and another plate inserted in exactly the same position. The patient has held perfectly still during this change. The .r-ray tube is then shifted '2] inches to either side and another radiograph is made. A pair of such pictures examined with a stereoscope gives a combined image in which the perspective is shown. Quite an idea may be obtained as to the distance of the foreign bod}' from the plate, but no exact measurement . Localization //// Trian(Jiilation.T\\\x is used in the same cases that are -unable for stereoscopic radiograph}' and gives much more accurate results. made with the head and the plates in the same mean- of a stereoscopic plate-holder, but with the tube her side for a distance of o inches after the first picture. anticathode being at a distance of 21 inches from the plate the dis- e that the iniau'e of the foreign body is shifted enables one to read i t he aut hor's table, page 807. its distance from 1 he plate (Fig. 504). po-itioii of the foreign body may be determined in this way to the i ion of an inch. fhe details of a more exact method of localization by triangulat ion lives the use of cross-wires marking exact]}" the same position on two -ucce--ive plate-, and also a solid metal object fastened upon iead at a portion in contact with the plate. This is more fully 1 in the -ertion upon the radioura ] ihic localization of foreign orbit. McKenzic Davidson's localizer is also excellent THE X-RAY 907 In some cases it is sufficient to use only one plate, making two sepa- rate exposures with the tube in two different positions. This produces two separate images of the foreign body on the same plate, but the rest of the picture is somewhat blurred. Such a radiograph (Fig. 50oj was taken of an empty skull with the .r-ray tube in two different positions. Two plates were used, but were in identical positions. If they are now superimposed, the brass springs and screws which hold the jaw in posit ion show double images. The screw on t he side nearest t he plate casts t wo shadows which almost coincide, while the screw on tin side of the skull opposite the plate casts two shadows which arc at a considerable distance apart. A calculation based upon the distance between the two images, the distance from the plate to the tube, and the distance bet ween the t wo different positions of the tube would give the distance from the plate to the screw. Two cases of .r-ray localization of bullets in the cranium and their successful removal were reported as early at IS!)!) by Lucas. 1 An interesting skiagraph by AY. A. C. Ilammel was published by Gamble and Tiffany," showing a chiml 4\ inches long which had been projected violently into a man's neck and had remained concealed in the tissues for sixty-nine days. The radiograph showed that the lower end of the chisel rested against if not in the bod}" of the fifth cervical vertebra, while the upper end extended an inch above the level of the hard palate. It had evidently gone downward and backward through the upper jaw bone. A case in which an .r-ray examination would doubtless have saved life was one which came to the attention of the author, though not under his care, before th:> discovery of the .r-ray. The patient had been struck on the head by a heavy piece of wood and sustained a scalp wound which healed promptly and the man seemed all right for some weeks, but then quite suddenly developed symptoms of brain abscess and died in a few days. It was found that a nail had been driven into the brain and had broken off (lush with the outer surface of the skull. One glance with the fluoroscope at the head in profile would have revealed the presence of this foreign body. A similar case is reported by O'Hanlon, Coroner's physician in !H)8 MEDICAL ELECTRICITY AND KONTGEN KAYS New York City, -Ian. 21, 1905. The patient was treated at one oi the hospitals for a scalp wound which healed promptly, but there- after the man began to have epileptiform convulsions. A radiograph was made sonic months later which showed a bullet lodged beneath the anterior lobe of the right hemisphere of thr brain. Hut the man had left that hospital before the plate was developed and during the entire eighteen months that he lived no one else suspected even the occurrence of a pistol wound. He died of an abscess of the brain and the ( 'eroner's physician discovered the bullet . The bullet itself appears to have been innocuous, but a fragment of the bullet with a sharp bit of bone adherent to it set up the irritation which eventuated in abscess of the brain and deal h. In a case reported by \\eiser 1 radiographs showed a bullet lying in ih" cerebellum. There were marked symptoms at first, but the bullet was not removed and the patient became apparently perfectly well. Foreign Bodies in the Orbit or the Eye -These are usually of small si/c and the exactness with which they must be located makes its accomplishment by means of the flucrosecpe alone require a dan- gerously long exposure. Hadiographic localization is based upon one of two general principles. By one method, not often used, an anteroposterior radiograph is taken upon a plate in front of the face, the tube being behind the head. Then a lateral radiograph is made upon a plate at the suspected side of the face with the tube- at the other side. These two pictures enable us to locate t lie foreign body at the intersection of two lines. In such a delicate organ as the eye. small fract ions of an inch, count for a great deal. The general topography of the cranial and facial bones, as shown in the radiograph, does nol" afford sufficiently minute exactness for this purpose. Land- marks are required, such as bit s of lead, which some operators have sewed fast at tin upper and 1 he lower border of 1 he cornea. The patient must be instructed to look straight ahead during the exposure to the.r-ray. The anteroposterior radiograph will show at what distance the foreign body lies from the vertical line passing through these two bits of lead, and 'hi lateral radiograph at what distance behind the same plane. Both radiographs show the level of the foreign body It is a matter of saving t he eye, and t hese bits of lead can be attache* 1 without anv mjiirv and without pain if cocain is used. This method is, therefore, perfect ]v proper if regarded as necessarv. A similar met hod is to fa. -ten a bit of lead on t he out side of the upper eyelid directly over the center of the pupil. th< lid being kept- closed by ;: bandage. The patient should be cautioned not to move the or . p on his side facing the plate; and later face up with the plate at the atlected side. Hie j:-ray tube may be enveloped in a shield with a leather disk to HoHoii Mefl. Surfi. Journ.. March '2'2. IdOti. THK .r-HAY 909 Schonberg's compression cylinder or The .r-ray tube should not he entirel arrest the soft rays, or Alber similar apparatus may he used. free. The anteroposterior picture is made with the tuhe at the same dis- tance 1 and position and with the same strength and quality of ray as recommended for anteroposterior frontal sinus radiographs. The lateral picture is much easier. The distance from the plate to the anticathode should he ahout 17 inches, the penetration about No. Benoist, and the exposure about half a minute with an induction- Fig, ofifi. Localizer for foreign bodies in the eye and orbit. (Sweet method). coil or a fraction of a second with a transformer or an unfluctuating converter. The head should be held perfectly still. sand-bags being used if necessary. Anything as large a.s a shot would be easily located in this way, but smaller objects, like small splinters of steel or glass, might not be discoverable in the anteropostcrior image. Localization />// 7Ymm////c///'o/?. This is the only method which is applicable to all cases, even those in which it is necessary to decide whether a spicule of steel or glass is imbedded in. the sclera or just, outside or inside. Sweet's apparatus (Fig. ")()(>) or Rowen's or Dixon's may be used. Th< principle is that two lateral pictures are taken with one or two hits of lead held in the same position close 1 to the eye while the tube is moved laterally. The distance and direction of the foreign body from the one or two hits of lead and from two cross wires in the two separate pictures form the basis of a geometric calculation from which the exact position of the foreign hod\- is found. Charts printed by Meyrowit/., of New York, give the result by a graphic process without algebraic formulas. One of the- bits of lead is held close to the eye and directly in front of the middle of the cornea: if the other is used, it points to the outer border of the eveball. 1110 MKDH'AL KLKCTHIC1TY AND KONTCKN HAYS Street'* iniihod is to have the patient lie face up with the. heau secured in an apparatus which includes also the holder for the hits of metal, and for the .r-rav tube and the photographic plate. It is not desirable for the patient to sit up and hold the plate against the side of the face. It would be difficult for him to hold still enough for the first picture and still more so when it came to removing the first plate and substituting the second. I)i.ron'x Ai>i>nr/!( n'.^ Arrangement.- This consists in having the patient lie with the affected side of the face resting upon a horizontal plate, with the tube over the opposite side of the face, and the two bits of lead fastened to a -tern whose heavy base rests upon the plate. In all these methods of localization by triangulation the first radio- irraph may be made with the tube in a line with the one or two bits of lead, or 1 ', inches to either side of that line. The second one is made with the tube moved 3 inches laterally, a little above the line of the one or two bits of lead. A stereoscopic plate-holder is convenient because it enables one to remove the first plate and insert the second without the patient moving. IT is not used because of any necessity that the two plates should be placed in absolutely the same position, so that the picture would come on exactly the same part of each plate, as in stereoscopic radiography. All that is required for th; present purpose is that the successive plates shall lie in the same plane. Some operators prefer to take both pictures upon different parts of the same plate to prevent their ever becoming separated or mixed up with radiographs of some other case. H<>avy I'-ad is placed over one part of the plate while the first picture is made; then the position of the plate is changed and the lead placed over the first part of the plate while the second picture' is made. 1 " 1 Tlie eye .-h.oiild be fixed in position, and if it is open this is best accomplished by placing a bright object at the proper position for the patient to look at. or he may look at the reflection of his own eye in a Mi'".ll mirror. Another way is to place the center bit of lead against the eyelid over the middle of the cornea with the eye closed. There i.~ then very little probability of the eye moving. I lie tube may be out in the open air or enveloped m a localizing -hii-ld or a compression cylinder may be used. The latter would not be i"!' compressing or even for immobilizing the head, but simply for its eiiect in cutting out secondary ravs. The author's preference is for a locali/ini: -hield with a sole-leather disk to arre.-t the soft ravs. liie radiograph i.- not a difficult one to make. The distance from Hi ' all ode to plate should be about 1^ inches; the penetration No. G THE X-RAY Oil Benoist for metallic objects, or No. 4 Benoist for bits of glass, and the exposure from fifteen seconds to a minute. Detail* of Localization hi/ Dijon'* Apparatus. The patient lies face upon the table with head clamped to the lateral plate-holder after the head has been squared by a special apparatus. This is to make the sagittal plane of the head parallel with that of the photographic plate (Figs. o(>S and /)(><)). It has been found that straps are not required to immobilize the patient's head. This object is better accomplished by an aluminum Fig. - r )fi7. Radiograph bv Dixon with his apparatus for localizing foreign bodies in the bar which is passed across for the patient to bite on and is firmly fastened in place. A small sand-bag makes an adjustable cushion for the head. The tube is placed with its antieathode at a measured distance of just .")() cm. from the plate and is normal to the plate at the intersection of th<> cross wires. This direction is obtained by sighting from a brass notch behind the plate and through the intersection of the wires. Fixation of the eye is obtained by having the patient look, chiefly with t he uninjured eye, of course, at a small wooden ball suspended about It) inches above the exact center of the cornea of the injured eye. This centering has been obtained by lowering the wooden ball to within a short distance of the injured eye and then adjusting the cross bar. from which it is suspended, until the ball is directly over the center of the cornea, and then pulling it up into position. The marker is a drop of solder on the end of a brass wire, which is fastened to an adjustable rod attached to the patient's head by a hand just like a forehead mirror for laryngoseopic or aural examinations. It is fastened directly in front of the middle of the cornea and at a measured distance. '_' or 3 mm., from it. MKDICAL KLKCTHK ITY AND ROXTGEN KAYS alizinsz foreign bodies in the eve. Safetv to operator r-niv tul>e should he pndosod in a protective shield . ."iiiv Dixon's method and patient reqture> tha ' Sliuwiiiu fixation of the eve in Dixon's method of localizinn foreign I in.-ikiiii! the first cxpo-urc the .r-i'ay tube i< lowered vertically I'lii- mean- liack\sanl with reference to the patient who is Ivinj THE X'-KAY 913 After the first exposure the tube is raised (1 cm. or 1o a point 3 cm. above 1 its normal position and the second exposure is made upon another plate. The calculation of the result requires only two preliminary measure- ments: the distance from the plate to the anticathode, and the distance from the coritea to the bit of lead. Quotations from a case in Dr. Dixon's monograph show how the localization is made. The distance from the anticathode to the plate "was 51.5 cm. and that from the cornea to the bit of lead, 'J mm. Take a piece of drawing paper and draw a line, a, right across it, which indicates the normal line at the intersection of the cross wires. A line marked b, at a right angle to a, and at a distance, in this par- ticular case, of 51.") cm., will indicate the vertical line along which the .r-ray tube is moved. A line, c, also at a right angle to this, near one end, will represent the plane of both the first and second photographic plates. The line a on the photographic plate represents the cross wire which is parallel with the. length of the patient's body, and the line b the wire at right angles with it. A measurement is made on the first plate of the distance from the line ' ; and from Ex. 2 to f) and x. The lines to x' and .r will be found to have crossed in space at a point which is marked .r"; and the lines to />' and o cross at o" . The direction and distance of the point x" from a line drawn through <>" parallel with c show whether the foreign body is toward the photo- graphic plate r or toward the median line of the head, and at what distance it lies from the vertical axis of the eye. Only one factor in the localization of the foreign body remains to be determined, and that is the distance above or below the horizontal axis of the eye. The distance from the cross wire b to the indicator should be the same on the two plates if the tube and head arj properly placed. These two distances are measured upon the line r in the diagram. Lines are drawn from the two points, .r 3 and <>'''. thus found to the middle point of the line b. The intersection of the line passing to /' with the line drawn through .r". parallel with the line r. shows the local ion of the ioreign boil}' upon a horizontal plane, while the inter- section of a line dra\vn to <>'" with a line drawn through o" and parallel with the line r, shows the position of the indicator on the same plane. Plotting these measurements upon the chart, in this particular case, we measure off 10 millimeters back from the center of the cornea, and MEDICAL KI,K( THH ITY AND KONTGEN KAYS' 8 millimeters below the hori/ontal plane, and (> millimeters to the temporal side, and thus indicate the point of location of the foreign body in rhc eye. The method of location by triamrulat ion is due partly to McKenzie Davidson and partly to Sweet. Vox, Hulen. Dixon. and Bowen. In making all the different measurements one should be careful to use the same part of the miaue of the foreign bod}-, if the latter is larger than a ni"re dot. It is easy to see how errors of a distance equal to the diameter of the foreign body miu'ht result if the same portion were not selected for all the different measurements. odv Kiiis. ">7(> and ~>~ 1 i wa.- so large that separate mea.-ur<-inent ,- were made to locate its different extremities. I '. - . ,,,:t, t ...;,- hi irk ! n iln ecu! >T ( il f i il'[ic;i ; ! -i [c Hi' ecu! i-r of ci ii'ii'-.i '!., .. .j-tr,,, '/,/:,, II cc-ntiT i:t' ci inil-!l ... T }.o mm 1 ..9.5 " 915 A radiographic examination should lie made in every case of injury to the eye by a foreign body when there is reduced visual acuity, whether there is a distinct history of pos.-ible penetration by a foreign body or not . The foreign Ix.dy may possibly be so small that its shadow escapes detection, but this is unlikely in an excellent radiograph. Allowance must sometimes be made for myopia or hypermetropia in calculating the position of the foreign body. The variation from the normal diameters of the eve-ball mav have to be considered. radiograph in Mir Inrali/atinn of tlie forricrn body in tin 1 eye (see DC Scmveinit/. 1 has observed slight variations which make it difficult to say wlu thcr a bird-shot is cither at or immediately outside or inside the sclera. The anteroposterior diameter of a normal eye varies from L'O to 125 millimeters, and in one case in which Dixon located the sh.m just outside the sclera Dr. Marble found ii to be ju-t inside. The man measured li t'cci _' inches in height and had an eye '_'(> millimeters in diameter. It' t his fact had been taken into consideration the location would probably have been c< irreet . Stilling states that variation in the diameter of the eye-ball is independent of errors of refraction and that a myopic eye of -1 D. may be actually >horter than a hyperopic eye. 'Journal Am. Mcd. Assw.. Aug. 11. 1!KM>. p. 122. MKIMCAL ELECTRICITY AND KoXTCKN HAYS The .r-ray may he used to ascertain whether a sliot which at first has been lodged in the vitreous, or elsewhere, has become loosened and fallen onto the ciliary body. Such a change in position might be followed by iridocyclitis. Cases have been reported by Marple 1 in which the x-ray has shown that there has been a double perforation of the eye-ball by a shot, the latter having gone completely through the eye-ball and being lodged in the tissue outside. The diagram reproduced in Fig. .">72 represents Dixon's chart for use in these cases. Radiography of the Ear and the Mastoid Cells. The classical pic- ture of this region is made in the method elaborated by Lange.-' The direction of the ray is from the .r-ray tube, placed on the opposite side at a point 2."r above the horizontal line between the auditory meati and 20 behind that line. The plate is pressed against the affected side of the 7j Week:- ami Di.xon'.- modififation of Swe-ei'.- cluiri for plotting location of for- tlii li(jilic.- in the <-yc jind oil.n head, the ear beinii bent forward. This ^ives a picture of one mastoid n-uion and includes the lateral sinus. Another .-ymmeti'ic radiograph i !n- made of the opposite nde tor coni])arison. A po.-itiou em|)lo\-ed by \\iii. II. Stewart" i> with the patient lying ip and with a -omewhat raised platform under the head so that the .! |-e.-ts upon the plate. The lube i> placed above the head, but \ ~t bad.. Thi- ui\'es a simultane7o-">77). Another is the extent to which softening and decay have taken place 1 in a tooth. Fig. o~S shows an upper central incisor in which a cavity at a considerable distance above 1 the gum-line was dis- covered and filled by Dr. ('has. ('. Allen, of Brooklyn. A couple of years later he sent the 1 patient tome suffering from indefinite slight sensitive- ness in the 1 sanu 1 tooth. The 1 picture showed an area of softening ex- tending far beyond the limits of the filling, and indicating probably the destruction of the nerve. Acting on my advice. Dr. Allen pressed the gum far enough back to get at this part of the tooth, found very little 918 MKIHCAL KLKCTHICITY AND RONTGEN HAYS I, Fiierupted upper bicuspid tooth. Apparatus making a space for it; Ii, port ion of lower jaw, >howinii presence of unurupted permanent teeth in a case in which all the temporary teeth \\ere persistent at the a<;e oi twenty years. Fin. ~~,-\. Uneniptod upper central infisor. l-'ij- r . "'> Persistent temporary lower The tooth itself bent and rotated. molar with uncrupted bicuspid. l-'ij.' .")7s. Caries of t !,.. root of upper centrrd inci or. IMack ma-~e- are fillirit:-: 8e\-nral beilitr at the proximal ancles (where two adjacent teeth are in contact.). T if;. ."7'.t. Kxtensive caries of the ami root of ujiper central inci>or. had l'\ been >l i.-pect C( I . THE .T-KAY of the nerve and removed thai, excavated, and filled a very large cavity in time to save 1 the tooth from breaking off. The condition of root-fillings and pivot teeth is easily determined (Figs. 580-580 ). In some cases an unerupted tooth is the cause of anxiety simply a> to tnclar has excellent pivot toot! bicuspid rout shows marked absorption the proper regulation of the teeth to accommodate it when it comes. In other cases the unerupted tooth is lying in a faulty position and causing harm in that way. Fig. o8(\ (young lady of seventeen, patient of Dr. J. S. Hasbrouck) shows an unerupted wisdom tooth growing in a 5N2. Crown and bridge work direction almost at a right angle to the molar tooth in front of it, and causing the sudden appearance of very severe pain, which had con- tinued without interruption for three 1 days. The cause 1 of the trouble was suspected, but the fact that the lower canine tooth on the same side MKD1CAL ELECTRICITY AND KONTCKN KAYS had not erupted made the .r-ray examination indispensable. A glance at the jaw with the author's dental fluoroscope showed the faulty di- rection of the wisdom tooth and the entire absence of tin 1 germ of the missing canine, and this was confirmed by the radiograph. Flu. .">."). Excellent root-filline in first In a yonn.tr .trirl (a patient of Dr. ('lias. O. Kimball) the left upper lateral incisor had betrun to bo 'everted and also rotated on its axis. A radiograph showed this to he due to the faulty position of the un- erupted canine, which as it developed was driving directly against the roi it of the incisor. Tin Author'* Dental Flnnroxcopc. All the above conditions are easily seen with the author's fluoroscope (Fisr. .~>S7), published in the International Dental Journal. .Inly'. I'.HM. This is shaped somewhat like a dental mirror or a laryngoscope, but instead of a reflect in; has a flu- oro-copic surface on both sides, so that either the side toward or away IP PHI the .r-my may be looked at. It i< placed inside the mouth, and the room beintr darkened, the .r-ray tube i- placed near the side of the face. 1 he niKiire of the teeth and mni- and e\'en ol the structure of iw -, inch beyond the ;ipex of the rool- -lio\\< very well. The tube -houM be of r;ither low \-acuiiin. iv-i-t;incr i_> inches and radio- 1: the current much lcs> than tor ;i radiotrmph, the anticathode from the face, and the expo-lire o)il\ ;i very few seconds. l'o| ii ;-' ;i \\.-i >. I he presence ;illd position i it the Ulienipted tooth 11KIV be ; ii ' ' a irlalice, and tin- i> entirely -;ite ;md may sullice for the wholi tion or may serve a- a s^uide in i;d point of view. I'.ut ;i piolonticd -tudv of THK .r-KAY \)2l the fluoroscopic image is as dangerous here as elsewhere. The study of detail should always be from the radiograph. The Author's Maynifyiny Fluoroscope (Fig. 588). This is a small trumpet-shaped metallic apparatus, about 4 inches long, closed at tin; large extremity by a fluoroscent screen with its coated surface inside. The smaller extremity has a flaring rim, which fits closely over one of the observer's eyes when in use, so as to exclude every particle of light. Fi^. .")>(. Tousey's dental fluoroscope. Its use is extremely dangerous to the operator and has been abandoned by the author. There is a magnifying lens in this end, which can be moved back and forth so as to focus the vision of the observer accurately upon the fluorescent screen, just as a jeweler's lens does upon his work. This fluoroscope is held close up against any part to be examined, and en- ables one to see details which are quite undiscoverable in the ordinary large fluoroscope. It may be used with advantage in dental fluoroscopy, applied to the outside of the affected side of the face while the tube is at the opposite Tousey's mairnifyinir fluorosco side. The lateral aspect of the upper jaw is accessible in this way for the study of the antrum, the alveolar process and alveoli, and the teeth. The latter are seen best with the tube at a lower level, so as to shine under the opposite teeth and then throuirh the roof of tin 4 mouth on the affected side. A >ingle glance at the fluoroscope will -how that the vacuum should be medium or low. With a fairly high decree of vacuum the roots of the teeth present hardly any contrast with the structure of the jaw. Quite 922 MKDICAL KI.K( TKKITY AND RONTCKN KAYS a fair derive of intensity is required. The operator's face is neces- sarily so near the x-ray tube in making this examination that reason- able precautions must !>e taken to prevent injury. The chief one will l>e the use of the shield with a sole-leather disk, limit ing the .r-ray to a small area and arresting the soft rays, \vhich are the ones likely to affect the operator's face. The use of lead-glass spectacles is desirable to protect the eyes. The hand should be protected by gloves opaque to the .r-ray. Kven with all these precautions, the examination subjects the operator to too much exposure to the .r-ray to render it desirable as a routine method. The presence of a "nasal" tooth, which might escape observation by ordinary radiographic methods of study of the teeth, will be detected at once by this method. It is similar in the result- yielded to the ordinary lateral radiograph of the whole face upon a plate placed at the affected side. Denial iluoroscopy is chiefly useful in detecting the presence and position of unerupted teeth. It is not so useful as radiography for the study of structural details and is exceedingly dangerous to the operator. Salvini 1 described a lens fluoroscope resembling the author's mag- nifying tluoroscope. Dental Radiography. For most cases the picture is produced upon a film, plate, or sensitized paper placed inside the mouth and closely applied to the inner surface of the teeth and gums. The .r-ray tube is placed at a distance of about 13 inches from the anticathocle to the fare. It is of very great advantage to have the tube surrounded by a localizing shield affording the operator almost complete protection, and shielding all parts of the patient ex""pt about the mouth. The operator making many such pictures, and sometimes having to hold the iili'i in po-it ion. would run a serious risk wit hout some such shield, while the pa: lent is not affected in any way by the fraction of a minute's e.x- posure to a moderate radiance. One of the most important facts in regard to t he ./'-ray is t he cumulative nature of its effect on t he tissues, and this ha.- been productive of many serious accidents to operators and experi- inenHTs. Considerable latitude in the degree of vacuum is permissible. Th-' resistance may be all the way from 2 to ( .) indies, but where the root- - are TO be studied we would not use the lowest degree of vacuum. F-inch resistance, b.~> kv.. and 10 ma. are preferable and the duration four to eight second.-, i See author's Exposure Table, page.s'jti.i The film for which these are the proper exposure is the Ka-t man positive cinematograph film, made by t he Kastman Kodak Com- pany, of Rochester and London. It is many times slower than the ordi- kodak film. The exposure for the latter would be correspondingly shorter, bui the picture produced is not so good. Kastman rapid dental ./-rav film, put on t he market in 1912, is excellent and about three times as po-itive cinematograph film, but does not give quite the Slip- of bromid paper require an exposure of fifty seconds h coil, and may be developed in any dimly lighted room. pirture may be made and pa-ted on a card within five r the patient comes into the office. The author made i-nlmur- AfH'i. Mcd. Chir. IVru<:i:i. I-Vhmarv. s, IMHi. THK Z-KAY 923 a radiograph by this process at a demonstration before the First District Dental Society of New York State, December 11. 1<)()4. The bromid paper is excellent for everything except fine details, and for these a film or a print made from a film is much belter. The films most useful are I 1 , by 1 ^ inches and come two in each packet ready for use. Ductile Film A/r/.v/x. --Packets containing two film- and having a ductile metal back can be bent to conform with the shape of the upper or lower jaw and will retain that shape. This makes it very much easier to hold the film in position, and the .r-ray-proof metal backing cuts off all secondary radiation from behind the film. This produces an improvement in the radiographs which is most evident in the abso- lute transparency of the image of gold crowns and other opaque objects. Such a packet U much more securely held in Leach's film carrier than a packet consisting of paraffin paper or the like. It is made by Buck. Kadiof/rnph of (he I'pixr T-th. The upper teeth are not easy to radiograph correctly. Owing to the flatness of the roof of the mouth it is impossible to place the film in a plane parallel with the long axis of the teeth. The film is held close against the roof of the mouth, and the inside of the gums and the head must be tipped toward the .r-ray tube ! Fig. .")()() i. If the proper angle between the surface of the film and t he direct ion of t he .r-ray is not secured the image' of t he teeth shows them elongated (like shadows about sunset or else foreshortened. The .r-ray tube is placed so that its anticathode is at a distance of about }'> inches from the sensitized film, and at such a distance above the level of the teeth that the image of the teeth upon the film will be as '.124 MKDICAI. KI.KCTKKTry AND KONTCKX HAYS near as possible the same length as the teeth themselves. If it were pos- -il>le to have t he film placed in contact wit h the whole length of the teeth and their roots, it \vouM make little difference at exactly what angle the t u lie \vas placed, hut as t he roof of t he inoiit h slopes away from the roots of t he t eet h t he film is not placet! in contact with t he roots or even exactly parallel with the loim' axis of the teeth. Some little study, therefore, i- needed to make t he i ma lie an accurate represent a I ion of t lie size of the tooth. An angle of '2'2 decrees will he found, in a rough approximation, to In- the cnrrect aiiii'le where the film is pressed against the teeth, gums. UppiT iiii-i-nt lei-til upi.li ;i linri/diital film. ' the mouth. The author ha- devi-ed certain little film-car- 1 lie helil in the mouth in a vertical po-ition. the film then i'l the lot in- axi- of the teeth. The Hide would have to ' ' e hori/ontal level of the teeth in order thai the image d tall upon the film. l>m it will lie readilv understood ' ' ' ' ' ould lie 1 he natural lentil h. '' TU II, I 'iinn n lltn-r.nnltil /'///. A very good ' ' > anterior t wo-t hird- of t he upper jaw and of the an lie mad*' I iy placiim the film liori/ontally '-in" the lip- and teeth upon it. \-\>r a picture of THK .T-KAY this character tlio position of the tube has to be decidedly higher than when the film is more nearly parallel with the axes of the teeth. An angle of 45 degrees will be found about right. The image of any par- ticular tooth is best produced when the tube is directly opposite that tooth, so that the x-ray shines through the space between that tooth and the adjacent ones and makes a clear shadow of the tooth in question without overlapping part of the adjacent teeth. Two or three teeth are shown very well in such a picture, while the natural curve of the jaw results in simply a confused mass for the teeth beyond. The apex of tin- root of any tooth is at a somewhat greater distance from the film than the crown of the tooth, and consequently its shadow is a little enlarged and a little less distinct than that of the crown. The enlargement. however, is not sufficient to interfere with the result. The lack of dis- tinctness is more noticeable when the picture is of rather poor quality than when it is absolutely first class. A ray which will give a really good image of the tooth through the maxillary bone loses very little of its distinctness in consequence of a slight increase in distance between the object and the film. To obtain the best possible definition the author always uses a small diaphragm in contact with the .r-ray tube, and makes certain that the small picture shall include the proper area by the ust 1 of a cylinder. The latter is not employed for compression or as a diaphragm, but simply as an indication of the direction of the rays. Two films. 2 x 2* inches, may be simply wrapped in black paper and paraf- fin paper or sheet rubber and held horizontally in the mouth by the patient. Such a picture requires a somewhat longer exposure than a picture taken upon a film held close to the inner surface of the teeth, the difference in time 1 being that, if the latter picture requires ten seconds, the former should be given fifteen seconds' exposure. These are average exposures with an induction-coil, and are reduced to one-sixth and one-fourth second wit h a transformer or an unfluctuating current generator. The patient's head does not require to be fastened, although he should be cautioned not to move during the exposure. He may be seated in an ordinary chair. The usefulness of this method is greatest in the upper jaw, and especially in cases of suspected unerupted teeth and a large cyst or ab- scess cavity, which sometimes forms in the upper jaw. Taking con- siderable pains to have the film held as far back as possible in the mouih one may get a very fair picture of the antrum, but the roots of the molar teeth are apt to be somewhat indistinctly represented and not to be shown in exactly their normal relation or length. The last upper molar can hardly be studied in this way at all. Figs. 501 to 500 are radio- graphs made by this method, and show different parts of the upper and lower jaws. For the lower jaw the position of the tube is at a lower level than the face, and the chin rests in the orifice of the locali/ing cylinder, which is at an angle of about 45 degrees. In all dental radiography the anticathode should be at least !> inches from the uch substance a> barium or lead oxid render them opaque to the .r-ray. were used, bin the tip of the forefinger of each one, and possibly the thumb, were cut 920 MEDICAL ELECTRICITY AND KONTGEN HAYS TIII-: .C-HAY 927 away. This may be done in such a way as to leave the dorsum of the thumb and forefinger protected by the glove while the palmar surface is free. A .better way in cases where it is practicable is to hold one edge of the film-packet in a pair of forceps, and in that way hold it in proper position inside of the patient's mouth. This will enable the operator to use gloves which have not had the fingers cut away, and also to have his hands beyond the range of the opening of the locali/ing shield. It will be difficult for the operator to hold the film absolutely still for the necessary length of time, and this difficulty is added to in some cases by involuntary motions on the part of the patient. The only place where the author has found this method at all easy is for the lower molar and bicuspid teeth. It is better and safer for the patient to hold the forceps after gently closing the mouth. The Author * Hand* Injured (>i/ Dental Radiography. The practice of holding the films in position proved exceedingly dangerous to the operator, who has to do it many hundred times, and left the author with incurable keratoses of the fingers, which if a little worse might have de- veloped into epithelioma. A little instruction will enable any patient to hold the film himself and so protect the operator from the danger of frequent exposures. Little film carriers (Figs. 597, 598, and 599) have been devised by the author for holding the film in this position by the patient simply closing his mouth upon them. One of these consists of a thin aluminum case Fig. ,507. Touspy's vertical film carrier. which, when closed, is nearly water-proof and entirely light-proof. It takes two films about 1X1,; inch.es in si/e, and without any paper or other wrapping. These must be put in the film-carrier in the dark, of course. There is a sort of flange soldered to this which the patient holds between his teeth, while the part containing the films is thereby held in position. These vary somewhat in form, according to whether they are for the upper or lower jaw, and as to whether they are for front or back teeth. To prevent any possibility of a patient swallowing such an instrument a short handle is provided'. This also facilitates placing 11 in proper position. Anything which enables the operator to dispense with holding the film in position by his bare fingers, unprotected by a pair of .r-ray proof gloves, or which will allow him to stand ent irely away from the patient, is extremely desirable. Leach's film carriers are very convenient for all the lower teeth. A method which has not been practiced very much, but which is an excellent one for the upper jaw. is to take a wax impression of the upper jaw just as for making a plate. Put the film in very thin wrappings so as to be quite flexible in the proper position upon this wax impres- sion ami replace it in the mouth. This is perfectly retained if the patient closes the mouth gently. Fiji. iV.tV I.rarhV film carriers. It is rather desirable that the films should not be bent or curved. Distortion of the image will he apt to occur and this might occasion an error in diagnosis. dult- whom the author ha- examined !>v the .r-ra\ in position with their own finger THK .r-KAY ( ,)2!) They must bo cautioned against involuntary movements, which would somewhat blur the image. Conditions Shown by the Radiograph. The radiograph shows all the conditions mentioned as shown by the Huoroscope and shows t hem bet ter. In addition, it shows the condition of the bone around the root of [the tooth; rarefaction caused by ulceration, absorption of the alveolus from Rills' disease or pyorrhea alveolaris, necrosis and sinus, fracture, neoplasm; also changes in the tooth itself, absorption of the root, peri- cementitis, pulp-stones; and also the condition of the antrum of High- more. Focal Infection of the Teeth. "A focal infection is a localized area of tissue filled with pathogenic micro-organisms, where, on account of physical reasons, natural drainage is impossible." ' The author had made thousands of radiographs of the teeth in cases of infection which gave local signs before it became known that dental infection might exist: for years unknown to the patient and the dentist. All this time the focus of infection is poisoning the system and is usually producing symptoms more 1 or less intermittently. Very commonly the dental infection is a blind abscess which shows distinctly enough in the radiograph, but may not be discovered by an ordinary dental examination. Those that cause systemic infection are not usually accompanied by pain and swelling, though there is often a history of the temporary existence of such symp- toms a long time previously. In fact, a tooth which has in this way presented evidence of acute infection should be regarded with suspicion ever afterward. The nerve may have died at that time and not have been removed, and the dentist now notes the ordinary evidences of a non-vital tooth: change in color and in translucency, insensibility to heat and cold and electricity. And if there is infection, even chronic and painless, the dentist will often detect sensitiveness on percussion. The .r-ray often settles the question at a glance by showing an abscess cavity or area of decalcification at the apex of the root. There are other cases of acute infection or of simply death of the nerve which have been treated by removal of the pulp and filling the pulp chamber and root canals. And if one of these subsequently becomes infected, the .r-ray may be the only positive means, except removing the root-filling or extracting the tooth, to determine, whether this dead and root-filled tooth is infected or not. Such teeth often form the anchorage for crown or bridge work. Pyor- rheal pockets are as evident to the dentist's ordinary instruments as in the radiograph. Symptoms and Lesions Due to Long-standing Dental Infection. The first symptoms are very apt to be neuralgia, neuritis, rheumatism, or indigestion. Recurring or persistent attacks of these troubles suggest the necessity for an .r-ray examination of the teeth. In cases where the focus of infection is not discovered and cured until a later stage, lesions are produced in the endocardium and arteries with all their possible serious or fatal sequelae, in the eye, in the stomach, and duodenum, where probably dental infection is the usual cause of ulcer and cancer, in the joints, and elsewhere. It has been found that in the Minnesota State General Hospital 12 per cent, of the patients were there because of disease caused by dental infection. The number and variety of the diseases, including many cases of insanity arising from this cause, makes 1 \V. D. Tracv, Jour, of Dental Research, vol. i, Xo. 3. September, 1919, p. i I XXXI. 930 MKDICAL ELK( THH'iTY AND RONTCK.N KAYS it a matter of the utmost importance to discover and cure dental in- fection while its secondary effects are trivial and curable. Infected thrombi arising from the heart valves and lodging in the brain, lungs, kidneys, spleen, or other vital parts are the immediate cause of painful and fatal complications in some cases of dental infection. The many writings of Hosenow and his wonderful investigations have shown that there is not only a causative but also a selective re- lation between focal infections and secondary lesions. Inoculation from a tooth abscess in a case with endocarditis may produce endocardi- tis; and from another case with gastric ulcer inoculations from a tooth abscess may produce ulcer of the stomach. Frank Hillings and the present author have made many important observations and so have a h< ist of ot hers. The author makes a set of dental radiographs in every case of cancer, wherever located, and has always found dental infect ion usually more severe than in cases already universally recou'iii/ed as due to that cause. The fact that newborn children may have cancer shows that dental infection cannot be responsible for all cases: but if cancer is ordinarily due to a germ which must be lodged for a long time there is no place in the body more suited to this permanent lodgment than a blind denial abscess. And it is the author's firm belief that the timely dis- covery and cure of all these abscesses would make a wonderful difference in the number of cases of cancer. Si/tn I/tout* of Dtiift/l Infection the only sure way of telling whether r>n instrument reaches just to the apical fotamen. and il is the cii.- torn of many dentists to employ this guide in their root fillings. 1,'iiil/iii/i'ti j>hi/ nf tin; I.ninr T<(tli.- For a radiograph of the lower teeth the film is held inside t he mouth as nearly parallel as possible to the lont: axis of the teeth and with its lower edge as low as possible. The patient should ffice in such a direction that the .r-ray will shine 1 between the teeth which are of principal interest, so that llieir shadows shall not overlap; and the head should be tipped slightly away from the .r-ray 1 1 1 be. J -Acept at 1 lie side- of the face t he degree of curvature of the jaw prevents a single pid ure from showing more than three or four teeth well. THCHNIC FOR DENTAL RADIOGRAPHY 1 . For Expert Rontgenologists with Every Safety Device. 'J. For the Dentist. I. Technic for the Rontgenologist. The best pictures of the teeth are obtained upon the >low Kastman dental films winch are the same .1- Huck Slow l)ental Film-, with an ant icat hode-skin distance of 13 . \\nli an exposure of five seconds except for the upper molars, THE X-RAY 931 where it is eight seconds. The current factors are 4-inch spark equiv- alent and 30 milliamperes. A protective x-ray-proof cylinder 3 inches in diameter lias its insulated rim 13 inches from the anticathodo and can be pressed lightly against the face for steadiness and accuracy. A l^-inch diaphragm opening is at about .") inches from the anticathode. The bull) is enclosed in a lead glass bowl and at a distant of about 5 inches from the anticathode is a filter of aluminum 1 millimeter thick, to arrest all ultraviolet rays and the softest x-rays. The Radiator Coolidge tube is the .r-ray tube best adapted to making a series of radiographs with this technic. The most convenient position for the upper teeth is with the patient sitting upright in a chair provided with a head rest, with the head erect and the occlusal surfaces of the upper teeth in a horizontal plane. The mouth is opened by dropping the lower jaw without moving the head. The most convenient position for the lower teeth is with the patient- sitting upright, the lower part of the body very well back in the chair, the chest drawn in and the head tipped back to the full natural extent and supported there by a head rest. The chin is to be up in the air. The film measures 1 ] x 1 [;- inches for the entire series now to be des- cribed. The direction of the long axis of the film is horizontal or ver- tical for different regions. For the upper incisors, film vertical, ex- tending slightly below the edge of the teeth, and pressed by the thumb so as to curve 1 laterally to fit the arch of the teeth, but not curved ver- tically. At it- upper end it re-t- auain-t the roof of the UK. nth, and near it- lower end auain-t the teeth, but it is not bent so as to follow the curve in the median plane between these two point.-. The opening in the protective cylinder i- a uood ^uide to the proper po.-ition of the tube. t~-ually the plane of thi- openin degrees from the perpendicular and slightly forward of a transverse vertical plane passing through the malar bone. The reason for using a longer exposure here is because of the density of the bony parts. The author has used almost exclusively Buck's slow dental film which is the same as the Kastman positive cine- matograph film and as the Kastman slow dental .r-ray film. But for this particular region the extra rapid film with a time exposure only one-fifth or less than with the regular film, i- being given a trial. The author believes thai for dental radiography the exposure should be so timed that the sensitized film may be developed all the way as evidenced by the image showing clearly on the back before it becomes TOO dark in front. This require- two or three minutes' development. A good way to test this matter is by givinsi one of these extra rapid films a direct exposure at/23 inches. 4-inch spark. 30 ma., part one second and part TWO seconds. As this is developed the front becomes entirely black be- fore the back shows more than a general slight discoloration within any division. Another film exposed for one-quarter and one-half second 934 MKD1CAL KLKCTHH'ITY AND HONTGKN HAYS develops more slowly, with a clear division of the darker and lighter portion-, both front and back. This is the way that a slow dental film should behave in the developer and the exposure should be timed accordingly. It may, however, prove impracticable with the rapid dental films. For all the upper teeth the patient's thumb is the most satis- factory film holder, just pressing the film into place, not holding it be- tween thumb and finuvr. For the upper incisors any kind of a film packet will do, but if it is not lamely made up of metal, care must be taken not to curve it vertically. For all the other upper pictures the desirability of bending either the upper front or the upper back corner mal-.r- :' e-.-enti:d to u~e ,-i packet made up lar^elv of pliable metal re- im any -hape mt.p which it i- bent. Racket- made up entirely of paraffin paper are much lr-- de-irabie here. 1 or the lower inci-Mir- the film i- vertical, curved laterally, so that it- ed'je- t;t in-ide the fir-t bicu-pid- and I he convexity i- ferward. Tt; lowi'i 1 edu.f pre--e- down the frcnum of i he tongue and should riot extend hori/ontally back under the toiitrue. luit the film should be a- iieariy vert:i-;i] a- po--ib]e. It dor- imt touch the lower incisors at all. : M the handle of I, each'- film carrier -hould pre-- back against the u]ip- : !i' i-or-. Ti siet the film far enouuh clown to show the jaw below t !M- a pier- of t he tert h require- t he i n t el i i-c 'tit co-operation of the THE X-RAY 935 patient. He must relax the muscles of the floor of the mouth so as to bring the teeth up in front of the film. A partial attempt to bite the film produce's the; right effect, bringing the teeth up and enabling one to press the film down. The author has no difficulty in making radio- graphs of his own lower incisors showing the lower edge of the jaw. The lower edge of the opening of the protective cylinder is close to or just below the chin. The direction of the .r-ray is from about 20 degrees below the plane of the occlusal surfaces of the lower teeth. Care must be taken that the wires or the terminals of the tube are not near enough to any part of the patient to give a spark. The exposure should be only four seconds and the development should be with special reference to securing detail below the apices of t he foots. If there is a metal rim, as with Buck's films, this serves as a guide. The lower part of the film should show decided contrast with the pure white of the margin. But we especially do not want to blot out details of the alveolar proc- ess between the roots of the lower incisors. The guides are sufficient darkening of the lower part of the picture, dark or black lines showing the root canals, not losing the imau'e of the cutting edge of the lower incisors. \\ j s much better to develop a little more rather than not enough. I'eduption will correct the former after the film is fixed and can be looked at by the ordinary light. For the lower cuspids and bicuspids the film is vertical, the lower front corner is bent back to allow the film to come well forward. The l) .-)<) MKlUt \I. KI.Kt TKKITY AND KnXTGKN HAYS film i- close In the teeth and MS nearly vertical as pos>ible. but the lower edLie mu-t lie a li'tle internal .-o as not to ])rower jaw and the direction of the .r-ray i- from about \~) decree- below the plane of the ocdusal surfaces of the lower teeth and from about 70 decrees in front of a coronal or lateral vertical plane pa hm through the iirM bicu-pid teeth. The patient mu-t relax and partly bite and partly press the film >o that the crowns of the lower teeth are close to its upper edsre. l-'oi- the lower molar- the loiiii axis of the film is horizontal, it must I'e in-ide t he upper a- well as the lower teet h. or it will be impossible to mlii LTUI liy of i),.' low. r mo i' far enough back to include the root of the lower third molar " r ""' extend- hori/ontallv backward. Leach'- film holder 1 ' ; " -'< . ;| i-i where to place the film. The lower ed^e be inclined inward -licihtlv to avoid a sen-hive led tie of bone. iu-t include- the fir-t molar. The upper edue is J U M 'Wli- ot the lower molar-. The patient relaxes and holdiny: the latter to make sure that the film does 1 'ci-M-ionally \\ith a chiM or ner\'ous patient who aniiot co-operate with you it \\ill be impos-ible !l e 1,-i-t lower molar root upon a film held inside case an external pirt ure i- made, placing Mle koilak film clip, tin- handle hciiifj; of metal only ,;, inch wide and very thii little over > indie- in diameter. The body and .-tern of the anti- cathode are directed away from the surface <:(' the ])atient instead of benin parallel tu the jtlate or film as in the slandard ('oolidge tube. Tlit 1 tube i- enclosed in a close-fitting lead gla^s shield protecting the operator and all parts of the patient except his face. The generator and with the slow dental films, which are usually preferable, should be about four seconds for all but the upper molars, for which it should !"!;_'. (10s. TouseyV clip holding a film. be -in, Mt eiMit seconds. The rapid dental films require about one-third a- long. / >< ilnfiiinj Clips /'/ l)tnlnl /'V////X. The clip- used by the author are ;i mollification of Hio-e -old by the Ka-tman Kodak Company. ttti have a l iook which i- hardly more than a bent wire. A hook i if ' : metal ', inch broad and 1 inch thick has the advantage of being more ea -i I y handled a nd I ving more securely in t he proper position over ! of the developing tray. The films lie flat in the tray and each film i- held in it- own clip during development, fixing, washing, and drying. for whole-ale work done po--ibly by someone who has !i'< - the time or t lie skill to watch the development of each film and to THE X-RAY 939 vary the time according to the results then 1 are multiple clips. These hold ten films to he developed ;i,t once in the same length of time re- quired for one film. The author uses individual film clips exclusively, with an i Development for Dental Fil/n*. Whether one film or two do/en are to he developed, the author prefers the tray. The progress of development of each film can he ohserved. And as each one approaches Fiji. 00'.). Uso of Tousev's clips for completion it may he taken out and held near enough to the safe ruhy light to look at hoth sides carefully; hut do not attempt to test it hy transmitted light. J/n!(///uj the Development of Denial /-'/7///X. First, the part not oh- structed hy the teeth or hone hecomes dark, then the outline of the light-colored teeth in the slightly darkened jaw. Later the teeth he- come somewhat darkened with metal iillintrs or crowns showing pure white and the root canals hlack; and the whole image 1 showing clearly on the hack of the film. Full development is indicated when the whole film looks hlack at a distance of IS inches from the lamp, hut the thin edges of the crowns of the teeth are still clearly visihle within (i inches of tin 1 lamp. A change 1 of the nature of a dark frost or veil over the imau'e- of the teeth indicate-- overdevelopment. The latter is not to hi 1 dreaded hecause it is easily corrected hy reduction, while underdevelopment is practically fatal. induction of Overdeveloped Tooth /-'/7///.S-. It is not always pos- sihle to judge of just exactly the hest density hy the ruhy light, and in heing ahsolutely sure to avoid underdevelopment some films will 940 MKDICAI. KI.F.t TKICITY AM) KONTCKN HAYS In 1 found too dense when viewed 1 >y ordinary transmitted liuht. These, whether they have Keen dried or not. are easily reduced in density. The process is carried out l>y ordinary li<;ht and is stopped when the him- have ju-t the proper density. After soaking in water the film is placed in the reducing solution: fiii- sixty >econds. Then, if not -uflicienl ly reduced, the film is placed in t he red i : chin >olut ion for twenty seconds, t hen washed, and then in the hypo for sixty -econd>. The twenty-second reduction- are repeated until reduction i- sufiicient. Do not overdo it. Kvery trace of the pic- 'ure can 1-e removed in this way. The reducing solution does not have in lie fre-hlv made. It can be used until it ceases to act. A stock -oiution of eiuht times this strength can lie kept on hand and lasts in- definitely. It i- very poisonous, (if course the stock solution i< diluted to one-eighth the strength with water, makintr the formula for actual use: Overexposure and full development may result in a film so dense as to tie entirely opaque, which when reduced idves very sharp con- trast. This i- far better than an overexposed and underdeveloped film or ;m underexposed and overdeveloped film of the same final den-ity. It is not -o uood. however, as a film which has been correctly exposed ;md inven normal development. 77" I in/ii/i S/niiriiii/ an tin ]>ame time by the developer to such an extent that one can only jud.uv of the effect upon the deeper partiHes of -ilver by the den-ity of the !i!m as te>ted by transmitted iiu'lit. And if you lose the i ma ire the film is likely to be entirely too 'i'-n-e. The projter density lies >ome\\'here between the first distinct di-colorat ion of th'- part to be depicted and the entire blackness of this part. A marinn covered by opaque metal diirinji the exposure fur- T ;:- i i-- :i ii-eful iruide to development because it doe- not become dis- lored, mill one -ooii become- accustomeil to juduc of the most de- -irable eoiili'a-1 betucen tin- white area and the important part of the film. The dupliti/ed dental film- are the -.-ime as other dupliti/cd film-. Tin-;, iri open to the objection that on account of their extra thick- lie they ;tre u-ually oiil\' one in a packet, while most dental packets M two -ini;le-coated film.-. A- a rule, -hid it underexposure and -linhi lopment re-nit in a -oft film lacking conti'ast of a nature in L;' ' be de-irable in a portrait photou'ra|)h and not so desirable iii -hde copy ot black and white dra\\inu-. A developer containini; im-tol or it- ecpiivaleni i- u-<-tul for produeinji an effect THK .T-KAY all the 1 way threiugh the 1 film as shown by tl plate e>r of a single-coated film. The Author'* (Ha** Mount for Dental Fil are faste'nerl be'twce'ii twe> she'Cts of picture-frame glass, pivseTving them from any injury and giving them pe'rfer-t transparency. Te>n 1-J x l inch films fe)rm the usual set and the 1 pieces e>f glass measure H x 10 ine-hes. Double-coated adhesive plaster (Janus plaster, sold for wig- making and e>ther mechanie-al pur- ] pe>se i s) is cut into strips {-ine-h wide 1 . A piee-e of glass laid upem the 1 table 1 has a complete 1 l)e>rde i r of plaster ] inch wiele 1 enclosing a central ami in which are fitted the 1 ten films with a elese-riptive label at erne 1 e'nel. Holding the cover-glass close and pressing lightly upon the films the 1 latter may be accurately petsitienierl with a paper cutter or a hat-pin. - : \\ he'n the cover-glass is once 1 presserl ~: elown it is held permanently by the 1 ^ ; e'ontae-t with the 1 elouble coatee! plas- te'r. A strip of white gummed tape ^\ forms a se>rt of passe-partout bind- ing all are)iinel the edge and forms a . border upon which certain brief notes may be written. Celluloid Film Mounts. These I ; are made either entirely erf gremnel 2 ; evlluloid, translucent but nett trans- ])are i nt, or e>f paper etr cardboard with gremnel e'elluloiel openings. They hold the films in sue-h a way that they e-an be 1 viewer! as a trans- parency if helel up te> a strong light. The\v do m>t give as clear definition as the glass mounts, but are invalu- able 1 when the films must be se>nt by mail. Interpretation of Dental Railio- yraph*.- - -Twe> methods e>f stuely are 1 available 1 : first, examination of the 1 film by transmitter! light; ami ser-- ; ond, examination of the print made 1 from the film. The Film. This pivse^nts pic- ture's (Figs. Gll-()14) in which the elensest parts, such as metallic fill- ings anel e-rown and bridge work, are 1 very totally opaque te) the x-ray prenlue'es an almo le image on the- hack e>f a m*.~ The 1 developed films light. An object almost st complete 1 !}- transparent 94l> MKIHCAL KI.KC TKUTIY AND RONTGEN RAYS image on the film. The part of the film which has been directly exposed to the .r-ray is black and almost opaque. The part which represents the lip is slightly less opaque, and can almost always be seen in the film. 1 he image ot the teeth is much more transparent, and appears nearly while by transmitted light. The root-canal and pulp-chamber appear somewhat darker than the body of the \< olh. The apical foramen may not be noticable in a normal adult tooth. It becomes clearly visible if a root-filling or any instrument passes ' ion |-'i. and especially !"]-. lilfi'. film -hould. if practicable, be expired with its sensiti/ed surface lube, and i- to be looked at by transmitted light, hold- 'ween the eye and an open window, or holding it over the u] M negative examining box. A magnifying glass or "n:" i; MJ i! be u-ed with advantage in the latter case. The film-Hiita h'j h'M away tVom the observer, the picture appears in THE X-KAY 943 its proper relations. This is as if the observer were inside the mouth, and should view by light transmitted through the jaw the teeth lying between his eye and the .r-ray tube. The latter simile applies to the radiographs made upon films held inside the mouth. A film or plate held outside the face should IK; exposed with its film surface toward the x-ray tube during the exposure, and should be examined with its film- surface toward the source of light and away from the observer in order to see objects in their true relation. This is as if the patient's head were, transparent and were placed between the observer and a light. The last case corresponds also to the image seen in the ordinary box (luoroscopc or in the author's magnifying fluoroscope. The Print. The sensiti/ed surface of the film or plate is placed next to that of the paper, as is always done in making a photographic print, unless there is some special centra-indication. This makes the print correspond exactly to the film when the latter is viewed in the proper way, i. c., with the sensitized surface away from the observer. A paper should be selected which will give; good contrast, and so Fiji, lil."). Apical foramina flaring in a -Apical foramen nanny: in an make pictures which will reproduce fairly well in a photo-engraving if the picture is To be used in illustrating an article. At the same time, the surface should be a smooth one. so that the finer details will not be obscured by the grain of the paper. ''({lossy velox,'' a paper made by the Kastman Kodak Company, has the proper surface, and has tones varying from white through var.ous shades of gray to black. Tt gives sufficient detail, and is easy to use because it requires only a few seconds' exposure to an ordinary electric or gaslight. It may be developed by the meTolhydrochinon .solution that is used for the films. Prints made upon solio paper require many minutes' exposure to sunlight, as these films are much denser than those produced by ordinary portrait or landscape photography. These prints, however, give some- what greater detail than the velox paper. They have a brownish-red color and reproduce very well in a photo-engraving. Thev are less apt to be permanent than the velox prints unless the toning and fixing are very thoroughly done. Ordinary portrait photographs, which gradually '.HI fade nut . are example- of 1 he lack of permanence found in papers of this class. The print present > an exact reversal of the lights and shadows of the tilm. The liackgroimd should lie a pure while, and metallic filling and crown and l>ridge work jet Mack. The teeth are next in darkness, and structure of the bone is gray. The normal antrum ap- pears almost white, and so do large cyts which have been emptied of liquid contents. 1'us in I he antrum gives a dark appearance at the most dependent poll ion. An alveolar abscess i< seen as a light area arouin I t lie apex oi 1 he root . The print is the exact duplicate of the tluoroscopic image. The alveolar process and the jaw show less transparency in the film than thi- I-'L'. ill , . Absees- at apex of central and lateral incisor-, with fir-tula in roof ot' mouth. ]-"j L r (>_'{). Incipient alveolar abscess ot loucr tirst f)icu-.pid and eroMon of apex. Second bicii-pid root lias been >qiiareiy ;ini]>utate. !eet h. ;i nd the details ol st ruct lire are well shown in a good film. Darker portions in the film or lighter portion^ in the prim indicate less density lie 1 M me. /. .nt,.: 1,'t n ah /I In/ tlir .r-l\tii/. An (ili't'olur uhxcrx* shows in its very H'ipieticy a- a darker area (if film for lighter in the print) surrounding v apex of the root i Kiy the dentist for an abscess of one of the lower bicuspids. There is danger that a healthy and vital lower second bicuspid may be drilled into, the nerve destroyed, and by an unfortunate chance the root canal infected, and in extreme cases the tooth be lost. No matter how much like an abscess it may look, it is always best to compare it with a radiograph of the same region on the opposite 1 side. If the right and left bicuspid regions show the same appearance it is doubtless due to the normal presence of the mental foramen. The x-ray is useful in locating a tooth or the particular root which is affected by alveolar abscess; also in discovering the cause of irritation in cast's of unerupted supernumerary teeth and other unsuspected ab- normalities. A blurred and lumpy appearance of the root suggests the possibility that the film may have moved during the exposure. Another picture should be made, using extra precautions against this. A perfectly clear tin 1)40 MKDICAL KI.KCTHICITV AND UONT(iKN HAYS picture will usually show whether some lesion has given the lumpy ap- pearance to the root in the blurred picture. A case of injhnnntntion and of loosening of the tooth from an im- perfectly fitting crown showed in one of Hhein's 1 radiographs an en- tirelv healthv condition of the alveolar socket. A ci/*t or ({hxccxx cavity in the bone shows as a dark area of film, or a light area in the print, with a clearly defined outline ( Fig. (122). \i (/O.-.-/N shows as a somewhat darker area than the portion of film, or lighter area than the portion of the print, representing normal bone. Tin- necrotif an -a is more transparent to the x-ray, which, therefore, darken.- the tilm more than el.-ewhere. ( )f course, it is lighter in the int. Thi- difference is only slight, however, and the picture requires irHation by one familiar with this department of radiography. ' ire of dead bone does not appear markedly different from that. ! bone in the radiograph, and there is often no sharply defined outline to the area ^I-'itr-. 02.'$ 02S). \ film ol the upper jaw. made upon a horizontal plane (Fig. 029), i'kmti- which correspond to the nasal fossa' and the antra. the author's radiographs (Fig. OM(b is of a case of necrosis and -tul;i, in which a liold probe enters a cavity in an upper central 1 Jour. AIIHT. M.'d. Assnr., .luly L'Y I'.tOii. THE X-RAY 947 Fifi- *>-';> Necrosis about upper lateral incisor. This tooth had been ex- tracted, the alveolus curetted, and the tooth reimplaiited with a porcelain crs. ^Necrosis about rout of up- per central incisor. The large apical foramina and the unerupted teeth -how t hat the pat lent j- ;1 < hiM. Fig. (il'it. Markings Fit.'. ('.:>(). Probe enters Fig. (JH1. Fracture of due to the no-triK not ca\'ity in central inci-or, lower jaw. I.etween the two to UfCT'Kis. pas-es throiiirh entire lenmh bicusjiid roots, of root, and eiiierire- in nostril. <)4S MF.IMCAI. KI.F.I TKK ITY AND KOXTCKX HAYS incisor, through the rout-canal ami the hone, to emerge from the nostril. An interesting feature of tins ease is the fact that the fistulous tract healed in a couple of weeks after the .r-ray exposures were made. The case was treated 1 >y I )r. (liven with the usual antiseptic and stimulant applications, both l>efore and after the .r-ray examination. The latter was made because the tract had refused to heal, and with reference to a po--ible operation, the necessity for which was obviated. The author reu'ard> it as probable that the exposure to the ray produced a beneficial effect and assisted in effect mil a cure. Piu. ;:$_'. Broken drill in root-canal. F'i-r. G'-M. Broken in-trument perforating the root laterally. A case of nccroxis and fistula may be shown by the .r-ray to be due to a retained broken root of a tooth or to a fragment of root-filling. The soft materials used for root-fillings show as dense bodies in a radio- graph. /'/'ir/urt of Hit- iiif'.-rior mnxUla shows upon a film held inside the mouth (Fig. >:}! >. but the picture is often difficult to make owing to pain. A radiograph made upon a plate held at the side of the face shows the fracture, but usually not very clearly. '"!< AI. KI.F.CTHICITY AM) R<>XT<;KN HAY showed that the metal point was lying in exactly the right direction. The patient returned to the dentist with the picture in less than an hour. (iuided by the picture, the drill was simply pressed straight ahead until something was felt to give way as it entered the abscess cavity. A couple of drops of pus welled, up through the cavity in the tooth and the pain was at once relieved. The radiograph is valuable as a guide to the complete removal of tJtc /"///> from cadi root to its very extremity. A frnrtun nf tin root of a tooth shows as a transverse line, but in the radiographs of the upper central incisors there is normally a transverse marking, which must be taken into account in making the diagnosis. furniture of tin root is well shown, and one should guard against the production of a false appearance 1 of flexion or curvature, due to bending the film while the radiograph is being made. The lii/frnl rnnts of the upper molar teeth ar: 1 difficult to show clearly unless they have root-fillings. The best way to accomplish the desired result seems to be to hold the film up as far as possible on the inside of the mouth, so that the tube will not have to be placed much above the horizontal level of the mouth. A somewhat greater distance, and longer and stronger exposure than usual is required. To make still more certain two radiographs should be made with the tube at decidedly Fit:. H'V.i. -Fir-t upper mnl:ir root Fitr. '',((). Kmpyrrna of tho nn- fi'Tn-tr.-iiinir imniiiil .-minim. I'yorrhc:il tnitn. Tin- upper trrth had bn extracted ' :iniiiinl l.itrr:il inri,,,r. t'ur -uppn-nl nciiralfriii. different lateral angle.-, but still not so far to either side as to cause the image- of the .-idjacent teeth to overlap th;ii of th<- one under examina- 1 he [ile;: of placing a small ./'-ray tube inside the mouth and the film on the outside doe- not seem very practical (see p. 771). \Ve require a much stroriL r <-r apparatus than any that can be used in this \V:i V. \ n'-tter plan than this is to place the tube at the opposite side of . and at a somewhat lower level, so as to shine through the open : '"d produce a picture upon a film held against the outside of the - > "'h a picture may show also both antra separatelv. THK .r-HAY 951 The object nearest the film is always depicted most clearly, and it almost completely obscures the other if the two images overlap. This explains the purpose accomplished by taking the picture of a buccal root upon a film held outside the teeth. The tube is enveloped in a localizing shield with a sole-leather disk. The anticathode is 11 inches from the film, and the exposure is about thirty seconds, with a penetration of Xo. 5 Benoist. and an intensity of No. 13 Tousey, or seven and a half seconds with an intensity of No. 15 Tousey. In making a radiograph of the ///>/>rr niolurx we are often influenced by a desire to show tin 1 relation of iheir roots to the antrum, and also the condition of the antrum, especially as to the presence of pus. The tube being placed at a higher level than the teeth, the image is apt to be somewhat distorted, and allowance must be made for this in estimating Fig. 0-1 1. Normal antrum. Small film held vertically in mouth. C'asr of neuralgia with all upper teeth extracted. Fig. 64L'. Normal antrum. Spicuhe of hone have heen removed along the alveolar mar- gin. Horizontal film. ( 'ase of neuralgia. the length of the different roots. The buccal root is apt to seem much shorter than it really is in a radiograph made with the film inside the mouth. The radiograph will show whether a root penetrates the antrum, as in Fig. (io'.t, but in a case in which the floor of the antrum dips down between the lingual and buccal roots the radiograph would seem to show both roots extending into the antrum. i.)'J MKim AL Ki.i:nKitiTY AND KONTOKN KAYS, /)/>< (/,v( N of tin Antrnni <>// a Small I'llni JIdd Inside tJiC Mouth. A hori/ontal tilni. like Fig. (>o9, or a vertical one, like Fig. 64], will show almost the entire extent of one antruni. The air space should seem very transparent a> compared with the dense teeth and even the le-- dense jaw .-tructure. A marked degree of opacity in the antruni mean.- pus or polypoid or granulation tissue. It was due to pus in Fig. till', which is of the patient whose large radiograph of all the pneumatic -inu-e- i- in ven on p. IHiS. All his upper teeth had been removed for pain, which was thought to l>e of neuralgic origin. A larger plate, showing the entire face, either laterally or antero- po.-ieriorly. is a necessary part of the examination in most cases. It -how- tlie extent to which the disease has involved the other pneumatic sinuses. Tinnitus atirium was the symptom which led to an .r-ray examination in one of Schamberg's cases. The radiograoh showed pyorrheal pockets aliout tiie root.- of some of the teeth communicating with the antruni by :. -mall opening, Fxtraction of the affect e root. Several such cases have been examined y t he a ut ho r. and in each case t he radiograph has shown whether there ha.- been any absorption, and. it so. to \\ hat extent i Fig. (144). The radiograph will show the condition of the roots of teeth which loiin i he anchorage for or are held in place by crown and bridge work Fin. ill." . Ill'- root- of a crowned tooth may be examined to determine the 'i' 'j"-<- ot ab.-oi'i it ion \\lnch has taken place. ' I, m it.- '/. lln Xr ]'//'/> <>f n Ttmth.- A -liuht irritat ion will not b<- recognizable by the .r-ray. but if it i- severe it will produce an area o] iran-hicencv around the apex ot the root indicating an incipient al- V-olar ab-ce--s; /' 1 1- '"' ' . I he-e concret ion- sho\\ as \ er\' defined opacnie ob- : the pul])-cavity of the tooth. They -ometimes, as in Fig. lib". : like exo>to-e- tVoin the bony wall of the pulp-chamber. '- Hunt.- ,,f Tif T/il,()riiloniv- ( '1 1 r( niic ab- THK .T-UAY 953 seesses at the roots of tooth have boon observed by J. Zilz 1 as an active starting-point for tuberculosis. .r-h'dij Findings in (V/xr.s of 1'neniptcd Teeth. The uneruptod superior canino (Fig. (>4(>) is usually found to bo present, and generally lios in a direction more nearly parallel with the median line than nor- mally, and usually on the lingual side of the other teeth. If it presses against the root of the lateral incisor a cvst cavitv (Fiji. ( >40) is often to readilv seen in lookintr at the film be soon there. The unerupted lower third molar is almost always found and frequently impacted (Fig. 047). The other molars and the bicuspids if much delayed in eruption are fully as apt to be found entirely absent as to bo present. It is a very serious mistake to extract a persistent temporary tooth in any of the locations, as was done in Fig. 048, without first using the .r-ray to find out whether the permanent tooth is present. 'reviously unsuspected" cyst A question sometimes arises as to whether a certain tooth is a per- sistent temporary molar or a permanent bicuspid. A radiograph of the tooth shows which it is, and if it is a persistent temporary tooth the pic- ture shows whether the germ of the permanent tooth is present (Fig. 1)49) or absent i Fig. (ioO). 954 MKDICAL KLKlTKU'ITV AND KONTCiKX HAYS Radiographic examinations show that absorption of the root of a temporary tooth is not entirely due to pressure of the oncoming per- manent tooth, but is a natural process which sometimes occurs when the permanent tooth is completely absent (Figs. (>.~>1 and 1)52). The most remarkable case in the author's experience is that of a young man. a patient of Dr. Allan, who at the age of twenty years still had every one of his first teeth. A series of radiographs, including traeted. Fiir. <>.">:). revealed the presence of all the permanent teeth still unerupted. The smallness of the first set of teeth gave an infantile expression to the face, so for looks a complete set of false teeth, upper and lower, were worn. The patient was thus going around with three complete sets of teeth. The radiograph will locate an unerupted second molar and show whether it is obstructed or is pressing upon the first molar. Such an 1 -'.'!'' n! L'erm of permanent per lateral under^oiim absorption, a examination would be desirable, as suggested by Hopkins, 1 in the case ot ;i i-hild M| ten or twelve years suffering from fret fulness and loss of appetite, \\nli iiTit:ited eyes and ears, anemia, and nervousness bor- dering < m h v-t rria . 1 iienipted teeth are often seen to lie in a kind of capsule, and very valuable mtorniat ion as to their probable period of eruption may be Jour \n,> T. Me,l. Assor., June :;o, I'.MIti, p. I'tv.t. TIIK X-KAY <),-,.-, gained from the degree of development of the tooth. This is perhaps more important than its proximity to the surface. Prolonged Retention of Deciduous Teeth or Their Itootx.- The roots of these teeth sometimes fail to l>e absorbed and deflect the oncoming per- manent tooth. A radiograph will show whether the roots in question are undergoing absorption or not. Portion of upper jaw in a " teeth persistent Fig. 652. Persistent temporary upper Fig. 653. Portion of up molar undergoing ahsorptioii, although per- case with all temporary tee nianent germ is absent. at the age of twenty yeans. Flint 1 cites many ways in which the .r-ray gives valuable informa- tion in orthodontia. Radiographic Measurement of the Permanent Teeth Before Eruption to Provide for Early Regulation of the Dental Arch if Their Size Necessitate* It. -This was the title of an article read by the author before the N. Y. In- stitute of Stomatology, November 9. 190(5. It was suggested by Hawley'* investigations in regard to the relation between the size and shape of the dental arch and the size of the different permanent teeth. Dr. Gillett Fig. 654. Angle at which the r-ray must he directed in order that the image of a tooth upon a horizontal film shall he about the actual length. called my attention to the advantage to be derived from an accurate measurement of the different permanent teeth a year or two before their eruption. Acting upon this idea, the author has made 1 radio- graphs of the temporary and unerupted permanent teeth in about 100 children. While there was every reason to believe that such pic- tures would give 1 an idea of the relative size before eruption, it seemed very desirable, indeed, to make a series of measurements to find out also how much magnified or reduced the .r-ray image of the erupted teeth was 1 Dr. D. W. Flint, Dental Cosmos, Nov., 1907. MKDICAL KI.Ki "I 'UK '1TV AND KO\T<;K\ HAYS as compared with measurements made at the same time from the actual teeth themselves. The leelh which had already erupted were measured bv means of a caliper square, graduated in hundredths dt' an inch, and at another time, without reference to these measure- ment-, others were made of the same teeth ;:s represented in the j li'i.'i i .' ,( i l'.-ulioL r r:iph~ u-ed in ine.'isiirilif: the uidth ot' the upper or lower :),< i -ur before i TII pi i' ni to pro\ i' le for e:irlv ri'Uiihi I ii m in csisc t hoc Icctli :irc too . tor tin' nri'li. lii I \<_'. IK'S, \vln-ri' one cc-nti-nl li:nl rrnptcil and the other li:nl not, 1 - ; irenielil were ec|ii;il. In -Hell pictures ;is 05U it i.^ e:is\' 'o >ee o i he i-eiil ::,! ini-i>or v tlie .r-ray to require a broad curve. (Knl i\- the permanent teeth in the same ea-e as Fill. GC'L' is still too rn,\\ for |ieriii:irii-iit teeth of t ha1 -l/.c. (Knlarficd.) oi the teeth ;MM| c> o! t lie lace, and the effect of undenlevel- r. e\-cn extend to the craiMai cavity and the I'l'aiu. THE OXRAY 959 Deviations of the septum and mouth-breathing unrelieved by the removal of adenoids and Tonsils, are among; the results of maldevelop- ment of the teeth with a too narrow and too highly arched hard palate. The object of my most recent work has been to determine beforehand the presence and position, and especially the size of the permanent teeth, before the loss of the temporary teeth. The latter may be quickly and easily trained to a curve of the proper radius and will then guide the per- manent teeth into proper position. ACTUAL WIDTH OF TEMPORARY AND PERMAXEXT CEXTRAL INCI- SORS (THE LATTER MEASURED SOME YEARS LATER) IX HUX- DREDTHS OF AX IXCII. ht upper entral. Xanii'. Matthew S.. Clara T. . . . ( Yeelia L. . . C.retchen W. Margaret F. Florence Y . Sissie R Jeanette S. . Xora F. . Ratio 1 to s 1(1 9 10 10 10 10 S 6 24 21 3s 1..V2 30 1.50 33 1.30 29 1.1C> 33 1 .25 34 1 .3(1 30 1 .57 31 1.3S 35 15 15} 14 1C) 1 , 14 11 2-U 22 21 19 21 21 23 1.03 1.42 1 .30 1 .28 1 .50 2.09 Actual measurements of the temporary teeth bear no fixed ratio to actual measurements of the permanent teeth. In a series of 7 cases, shown in table above, the ratio varied oO per cent; in the same cases untreated, the curve of the temporary arch, whether suitable for the permanent teeth or not, was reproduced in the permanent arch. A'-ray measurements of the width of the imerupted permanent upper and lower central incisors at the age of five or six years correspond within -y-Jf,; inch with the actual measurements of the same teeth five years later, after eruption, as shown in the following table. PERM \XEXT CEXTRAL IXCISORS MEASURED R ADIOC.RAPHICALLY BEFORE ERITT10X AXD ACTUALLY SOME YEARS LATER AFTER ERUPTIOX. (Xumbers arc in Hundredth* of an Inch.) Tooth. Radiograph uiicniptcd. Matthew S. Clara T. .. Clara T. . . Cecelia L. (iretchen \V Florence R.. Sissie R . . . . Jeanette S. , Jeanette S. . Left 1 "pper ( '(Mitral 39 Hinlit Upper C Mitral. 30 Right Lower ( ' Mitral >> Right Upper C Mitral 34 oblique Right Upper C Mitral 29 Right Upper C Mitral 35 Left 1 "pper Central 30 Left Upper Cnctral. Right Lower Central. 32 21 J MF.DICAI. KLKCTKICITV A XI) HoXTOKX HAYS The author'.- technic is as follows: The temporary centrals arc meas- ured with a sharp-pointed ealiper square with a screw adjustment, and graduated in hundredth* of an inch. A wax impression ot the curve of the temporary upper and lower arches is made. Radiographs, or .r-ray pictures i Kins. 002 and 00^:. are made of the unerupted upper and lower central incisors and the width of the images of these teeth is meas- ured i Kig. 004 i. A curve suitable for permanent teeth of this size is calculated by a modification of Hawley's and Bomvill's tables. My work shows the sixe that the permanent teeth will have and the radius of the curve required to acconiodate them. The temporary bite is photographed f p<-n!i:ti!>-tit (l<-nt;d r-irdc fron. .r-nty mi'it-urr-mciit of the upper : the actual curve formed by the cuttinir edires of the incisors, the i- ot the canines, and the buccal cusps of the bicuspids and molars, upon the -ame photograph is drawn the correct curve i Kig. 005) to mirnodate permanent teeth of the -ixe determined by the x-ray. idonlisi may regulate the temporary teeth to this curve, and uide t he permanent teeth into proper position as they erupt. Kigure how- the -Mine case as Kig. 002, in winch the temporary curve was li for permanent teeth of the size shown by the .r-ray. The ca>e ;. and five years later the curve formed by the erupted 'eetl i v, ;t- ,i contracted one of the -ame radius as that origin- he temporary teeth. THK .r-KAY 91)1 Take the width of one permanent upper central incisor, double it, and add 0.24 inch to get the radius of the circle formed by the six upper front teeth (cutting edge of incisors and cusps of canine). Add ~>0 per cent, to t hat , and you have t he distance in a straight line from the middle of the anterior surface of the first permanent upper molar to the space between the two centrals. After drawing the circle use the radius from A to get the distal points of the canines ./ and //. From (', draw lines through ./ and // to the tangent and so get /',' and I). I'se /,' I) as radius of a circle whose center is at /. Starting from A in both directions measure off the length of the radius six times and so get the inscribed isosceles triangle, .-1, F. C '. Draw lin<'- //. ( ' and ./. /". The outer cusps of the bicuspids and molars lie alonu the-e two straight lines. The marvelously beneficial effect of (>) drawn by llif rhinologist, Dr. IVren^, after treatment by the dentist. Dr. K. A. Bogue. Stfi'cnxcopfc RfHlioijrnphs in D/i/lnl II nrl:. Two types of radiographs are available: one upon two successive 1 films held inside the mouth, and the other upon two successive films, or plates, held against the outside MKD1CAL KI.KCTKMITY AND KoXTCKX KAYS of the fare. The latter pictures, like Fig. (iCiT, .1 and 7>, take in a wide area and show the topography of the teeth, upper and lo\ver jaws, and tongue in their natural perspective. The pictures may he made upon small films held inside the mouth when the perspective of the a l-'in. 6P>6. Deviations of the nasal septum in a youi'tr child straightened in a few weeks by regulation of the teeth. (Dental treatment by Dr. K. A. Hogue; nasal exam- inaticiti and diagrams by Dr. Herons..) roots of an individual tooth, or that of the roots of adjacent teeth, or of an unerupted tooth and the roots of the neighboring teeth, is desired. The object in the latter case is to find out whether the unerupted tooth is on the buccal or the labial aspect. It is easy to misinterpret a pair of these little stereoscopic pictures if they are pasted in the wrong positions upon the card, so that the left eye looks through the stereo- scope at the picture which should bo placed before the right eye. pie radiograph of the upper and lower iuws. I he -mall stereoscopic pictures are made in the same way as dental evepl lh:il two -eparate exposures arc made upon suc- ' film- held in exactly the same portion in.-ide the mouth, while moved '_!.', indie- laterally before taking the second picture. iioper di-placement lor rjidiogi'aplis made upon a hon- ii the aiit icathode about \'.\ iiirhe.- di.-lanl from the film. I! inrhe- i.- bet ter where an external plat e is used and ''. I; che>. I U)l h of t IICM \ i. Id good results, be- rau-i i I i po-ii ioii of the pa ! ient and I he film or plate and I he TIIK .r-HAY 903 x-ray tube may bo exactly duplicated. They both show the perspective of a large part of the jaw, and (lie posit ion 'of (ho unerupted as well as the erupted teeth. The smaller films, held parallel with the axis of the teeth, present greater difficulties in securing the same relative position of patient and film and .r-ray tube, and are, therefore, less apt to yield satisfactory re- sults. The anticathodc should be 13 inches from the film, and should be displaced 4 inches before the second picture is made. These pictures, if successful, show the perspective of parts of an individual tooth, and' for example, would reveal the fact that a root-filling perforated the root either buccally or lingually. Fig. fiOS shows the principle upon which this is based. The position "!., tn <\ tu l )0 in the first picture is marked T 1 and in the second picture Two bodies at different distances from the film an; marked by a square (D) and a triangle (A) cast, the images marked (D 1 ) and (A'j in f r the first picture and (C' J ) and (A' 2 ) in the second picture. These four images are not all upon the same film; (~. ] ) and (A 1 ) are upon one film, and the other two upon 1 he second film. A moment's study will show that motion of the tube in one direction disj daces 1 he images of all bodies m the opposite direction. Object s at a distance from the film undergo greater displacement than those near it. Examining the two pictures, we should find that the image of the object further from the film is displaced in the opposite direction (with refer- ence to the object nearest the lirnn from that in which the tube is shifted. The author likes this method of studying the two small pic- tures better than by combined vrsion with the stereoscope. If the stereoscope is to be used care must be taken to hold the film with its sensiti/ed surface toward the .r-ray tube. The print made from the film exposed with the .r-ray tube farthest to the patient'- ief; should lie pa-ted upon the card so as to be looked at with the observer's right eye, and the print from the other film is looked at with the left e\ e. The perspective is then as if the observer's eyes, placed in the two positions of the .r-ray tube, looked at a transparent jaw. objects which look farthest away are on the lingual aspect: tiio>e that look lira re! 1 a re on t he 1 uiccal asj tec 1 . . '.Mil i:u:< nJii ITY AND KO.NTCKN KAYS I)i terininiition of I\ rxj>c<'tirc in a Sintjlc Kiufiot/rtifih of tfic Tcelfi. The determination of the relative position of two teeth whose images overlap each other can usually be made by a careful study of a single radiograph. The ima^e of the tooth nearer the plate i.- markedly more distinct and clearly defined. Fig. (>(19 shows this fact. The image of the unerupted canine i< only rendered denser by the presence of other teet h. while t he images of t In- hit ter are obscured and rendered less easy to tract' where the overlapping occurs. Where the imaires of the adjacent borders of two teeth overlap in an .r-ray picture the image is more than twice as dense as that of either of the thin borders alone. Successive portions of dense substances ab- sorb more and more of the rays which have an effect upon a sensitized film. After traversing a certain thickness of dense tissue the radiation produces no visible effect upon the film. Radiography of the Inferior Denial A'ew. Radiographs of the bony canal which this nerve traverses in the lo\vr jaw may be made in two ways. A film ]]' 2 inches long may be held inside the mouth and pressed clo-ely again>t the inner surface of the jaw from the region of the canine tooth backward. The upper margin of the film should not be above the crowns of the teeth, while the lower margin should extend well below the roots. The .r-ray tube should be at the ame side of the face and opposite the second molar tooth at a distance of 14 inches from the anticathode to the film. The .r-ray should be of a high de- gree of penetration. Xo. S Benoist, and the exposure will be twelve seconds with a 12-inch coil or about one-fourth -econd with an un- fluctuating converter or a transformer. The object is to obtain a picture showing as great detail as possible in the bony structure of the jaw. even at 1 he expense of a certain degree of ' cont rast in the radiograph. Fig. t'71 -hows a gold plug in the inferior "'" dental canal. It wa- placed there six years previously, to prevent regeneration of the nerve after re-ection. It could be seen very _ fluoro-cope and the .r-ray tube held at the oppo- the lace. I; -eemed to be acting as an irritant foreign other method i- to make a radi- .graph on a plate held at the t the jaw with the .r-ray tube at the opposite nde of the face. a level as to shine from under the opposite side r it may lie directly opposite and .-hine riirht c ide<, but xi near thai while the image of the affected learly defined that of the opposite side is enlarged and vague. 'i the expo-ure -hould be rather long and strong, and the ' penetration rather hiyh penetration. No. s Benoi.-t ; exposure l, or about one -econd with a transformer 12-inch c latino con vi Tt e v "t" the br. - an iin-u~p TIIK .T-RAY Radiography of the Inferior Maxilla.- -Under this heading rnay bo described tho making of a picture upon a pinto hold against tho outside of tho faoo, tho tube being at th.o opposite side of tho patient. Such a Fig. 070. Inferior dental canal in case ot' neuralgia. The teetli had been ex- tracted long lx;fore. Fig. 671. Arrow points to gold plug plaeed in inferior dental canal after resee- t ion of the nerve. picture does not give as good an image of any of the teeth as the other method, but it does enable us to radiograph the articulation of the jaw and to examine the condyle and ramus of the jaw for a fracture. u f . li7J. Radiography of the inferior dental nerve upon a plate outside of the face pic plate-holder i- shown. plate in it.- opaque envelopes can be ex- chtuiged for another without unv movement on thr part of the patient Throe methods are excellent: Fir*t, a pair of stereoscopic radio- graphs, ant icat hode 21 inches from tho plate, and vertically over the external auditory moatus in one picture, and over the front of the MKDH AI. KI.K(TKiem AND KONTCHN KAYS mouth in tlu- companion picture. Distance '2'^ inches exposure for each picture .Vmdi resistance or >park equivalent , (\~) kv., ol) ma. for three secoiuls or 10 ma. for nine seconds, for a l.'iO-poiiiHl man, with an iiitc-n-'ifviiiii' scieen. or two oi 1 three times the duration without one. Further detail< of thi- met hod are i:iven under the head of stereoscopic radiography. As applied to the face it ;i'ives tiood anatomic detail, for in-taiice, of the variou- pneumatic sinn>es. Seconil, the tulie and the head may he so placed lhat the .r-ray will shine under the opposite >ide of the jaw and through the (loor of the Mini I he ;i!'t'ec1cd side of tlie jaw. the plate lieinu' ;it tha.1 side of ice. \Viih a liltie care a picture ina\ lie cihtained in which the - of aluiK-1 thi entire r:imtl.< and half of the liody of the lower ' iwn, llii- imaire of the oppo-ite -ide of the j;i\\- falling at a i i on 'he pl;iie. The exposure i- the -ame as for the pre\ious ' I ime i- required. normal art iiaila! ion of the lower jaw ( Fiir. (\7'.\) ;ih clo-ed or only -liuhtly opened -how the con- rlyio ' .deiioid fo>~a. \\ith wider o)enin^ tli( % con- TIIK .r-HAY %7 forward upon the eminentia articularis. A dislocation is shown as an exaggeration of this normal displacement 1o a point beyond the emi- nent ia articularis. The conditions revealed by the x-ray in a typic case of long-standing ankylosis of the jaw are described byCryer. 1 The angle of the chin, or mental process, is drawn back and the angle of the jaw downward. These are due to imperfect development under the abnormal conditions. The ./--Ray in the Differential Diagnosis of Facial Neuralgia. The x-ray has an undoubted action in relieving pain, as shown in cancer and rheumatism, and it is effective in many forms of neuralgia. There are certain cases in which the nature or the position of the pathologic lesion renders a curt 1 impossible except by surgical removal (.if the cause of the trouble. The x-ray will often be of service in the differential diagnosis of neuralgia. A case illustrating this is shown in Fiu 1 . (174. The patient., a lady about fifty years of au~e, was sent to me for Kontgen diagnosis by Dr. X. B. Potter of this city. She had >ui'fered for three years from very severe pain near the angle of the lower jaw. all the teeth except the last molar had been extracted from that part of the jaw without relief. Med- ical treatment, phototherapy, and electrotherapy had been applied by ' Dental Cosmos, Jan., llHI"). p. 1.1. MF.lHi AI. Kl.F.c TKH 11 V AND KoNTCKN HAYS specialists in Now York and Paris without success. An operation was under consideration for removal of the (lasserian ganglion, or of the origin of the third division of the fifth cranial nerve. The radiograph was taken with the affected side of the patient's face lying upon the plate and with the .r-ray tube above the opposite side of the face. This .Allowed a large molar tooth imbedded in the jaw-bone behind the only ilar ,"iid crowing again>t its root. The operation for the re- ;i tooth was a serious one. and followed by suppuration v-nial incisions. There has been gradual improvement I r< iin the effects of t lie opera t ion. ( 'hanue of climate and 'he LM'tirrai health promi.-e ;i cure. The menopause mav havi had -omethiim In do with the neuralgia. AIH i-lrative case is the one shown in I ; ig. l>7."). The patient Tin; .C-KAY 900 is himself a physician, und hud suffered for some your.- from pain in the upper juw. All the upper teeth hud been extruded, und at various times spicuke of bone had been removed from the maxilla. He con- tinued to suffer from pain, and was unable to wear a set of false tooth for more than an hour at u time. The r-ruy examination included a number of radiographs from different directions. The one reproduced reveals the nature of the case dourly. This radiograph was made with the chiefly affected side of the face lying upon the plate und with the tube over the opposite side. It showed un area of opacity where the normal transluconcy of the ant rum, or maxillary sinus, should have been. This was due to chronic suppuration in the ant ruin, which was cured by an operation performed by Dr. Cryer. An .r-ruy examination in un obstinate case of neuralgia about the face should exclude; suppuration or polypoid growth in the untrnrn: cyst, abscess, or tumor of the maxilla; retained broken roots of teeth; unerupted teeth, especially third molar teeth; und the different lesions which may affect the root or the root-canal of u tooth or its alveolus; and the presence of a foreign body, such as a broken drill or a part of a root-filling, piercing the root of a tooth und projecting into the alveolus. The inferior dental nerve is liable to compression or irritation during its passage; through its bony canal, und a gooel radiograph of this part of the juw is often of the* greate-st value. Certain intracruniul conditions would bo semght when the clinical history suggested such un examination. The .r-ruy reveals the presence of tumor, or ubse-oss, orhematemia etf the 1 brain, osseous tumor, sinusitis and pachymeningitis. Benedikt has especially studied the radio- gruphic appearance 1 of intrueTuniul lesions. The ,r-Ray in the Diagnosis of Disease of the Pneumatic Sinuses of the Face. The 1 fluoroscope 1 shows the- size- und shape 1 of the different sinuses, und also whether they form the normal air spaces e>r are made more opaque, for instance, by pus. Such an examination, however, is not dependent upon for two reusems: the .r-ruy would have to be very perfectly applied to produce a first-class fluoroseopic image' and an ac- curate diagnosis e>f the 1 frontal sinus, und would require so long a study as to bo unsafe. Some ejpeM'utors, however, like Culdwoll. make a very brief fluoroscopie- examination to see whether everything is ad- justod for the best possible radiograph. This, however, is undesirable unless absolutely nee-essury. Radiography of the Frontal Sinus. The radiograph may be made rithor from a late'ral or an anteroposterior direction. LnU'i'ul. The plate is to be at one side of the patient'.- head and the 1 j-ray tube at the either, the normal line 1 , passing through the frontal sinus. The position of the patient's head is partly a matter of convenience. The plate, for in-taiice, may be- hori/ont al, and the patient he with the of his face resting upon it ( Fi.u. (>7t>). Or the author's lateral plate- the stereoscopic plate-carrier in a vertical position, les face upward with I he 1 side 1 < >t his head close against This apparatus makes it easy to make a preliminary lation in exceptional cast's, and makes it easier tor the operate)! 1 to protect himself from the .r-ruy than if the x-ray tubf we're' below the head and the screen held over it. The- anticathoele of the tube should be at a eli-tance of 30 inches MKDHAl, KLKlTHK'lTY AND KOXTCKX HAYS from the plate. The equivalent spark preferred by the author is ."> inche-. (i") kv.. MO ma., for four seconds, or 10 milliamperes for twelve >econd- for a bill-pound man, using an intensifying screen (see Exposure Table, pa lie S'.Ul'. It i- very convenient to have the tube enveloped in a localizing shield which limits the rays to the required direction, and which the author supplements by the u.-e of a sole-leather or aluminum disk to arre-t t he soft rays. The indication- to be gathered from a lateral radiograph of the frontal -inns relate chiefly to its condition near the median line where it i- -een in profile. It- anteroposterior and vertical measurements are rendered visible, and the radiograph shows whether this part of the frontal -inns is occupied by air or by some opaque substance like pus. In "!: of the author'- radiograph- i Fiii. (17 < the p<>-1erior wall of the -inu- -hows irregular -harp bony point- and the infundibulum H-H. diouraph o| the frontal sinu- i- n-iially -o distinct as to ot h in t he plate and in a print m.-n le fn nn it . and I'ancoa-t 1 have made succe-slul lateral radiographs ot her pneumatic -muse- by u-inir a hiuh deuree of rail ui/rn /ill* ot the frontal and maxillary sinuses and \\ere, 1 believe, fir.-t siicecssfully made in Killian's . I' ''' ! mull i/iii/ilinii/in <>, ,/','-/ of excellent antero- TIIK .r-KAY 971 posterior radiographs of the frontal sinus made, under his direction, I believe, by Caldwell and others. 1 Loeb, of St. Louis, has also done similar work. The radiograph should show the orbits, the nasal bones, turbinated bones, traces of the sagittal suture in the frontal bone, and coronoicl suture. The size and shape of the frontal sinus can be determined, also the position of the septum and of any accessory septa. CoakleyV conclusions are: First, it is possible by means of a skia- graph to determine the presence or absence of a frontal sinus which extends vertically above the glabella Second, a frontal sinus may be small, parallel with the upper, inner manrin of the orbit and not detected in the skiagraph. Third, in all cases of unilateral disease of the frontal sinus verified by operation a cloudines< has been observed in part or all of the area occupied by the sinus, and an indistinctness in the outline of the cavity as compared with the opposite or healthy side. This is a very much more difficult radiograph to make, and even the most expert radiologist may expect a certain number of complete 072 MKDICAI. KI.Kt THU MTV AND KONTt.KN HAYS failures before acquiring the correct tcchnic. The difficulty lies in the fact that the .r-ray must penetrate the entire thickness of the head from behind forward sufficiently to act upon a photographic plate, and still be capable of sufficient selective absorption to show the differences in densitv at the region of the frontal sinus. Some plates will be found not to show sufficient effect from the .r-ray, and this may be due either to the use of too hi.u'h a decree of vacuum (the rays pa.-simr ritrht through tin* plate without chemic effect), to too low a decree of vacuum (the ravs all being absorbed by the 7 or 8 inches of tissue), or bv too weak an intensity or too short an exposure. < >u the other hand, the plate may show sufficient density, but in- sullicient detail everywhere. This condition may occur with a long or strong exposure to a ray which has too great penetration and to which [en>er parts of the head are almost as transparent as those less dense. In this case more than in any other contrast is desirable rather than the trreatest detail. [;, 'ti Position* of the Tube, Plate, ami P,iticnCx Head. This is of the greatest importance. The tube must, of course, be in the median line at the back of the head and the plate in front. Many radiographs show a good picture of the aiitrum and ethmoid cells, but scarcely anything of the frontal sinus. This maybe due to the :,;' that the tube is in such a position that the image of the thickened ::::;-- of bone at the occipital protuberance is thrown directly upon that of the frontal sinus. Other radiographs of the accessory pneumatic -iii'i-es of the face have the image of the ethmoid cells or antrum ibsciired by the shallow of the petrous portion of the temporal bone. Tii 1 ' .-hadow of the horizontal plate of the frontal bone should not fall >-- t he orbit , bur just at its upper border. i'he -hadow of the horizontal plate of the frontal bone should not 1 upon that of the frontal sinus. The shadow of the petrous portion ' the temporal bone should not fall on t hat of the antrum. nor that of isillar proce>> of the occipital bone on the shadow of the ethmoid il~. There i- only one position which satisfactorily avoids all defects: i I- patient's forehead and nose -hoiild be pressed against the piate. [!>< -hould be behind the head, in the mei haii line, and along a fine ' >;; the glabella (junction of nose M nd forehead) backward ' ' in the skull, which i- usually to be f<>h as a slight de- i 1 ;,'- above the occipital protuberance. ' irection has also been described M'aldwell) as alon.tr a .'- above the line joining ihe u'lal, pav977). This is the author's usual position. Reid's line from the Fit:. G7is. liadiographv of ihc frnntal r-inus with the patient lying fact- down. A di phragm or cylinder should ! u>cd external auditory meatus to tlie u'labella is horizontal and the .r-ray tube is '2'.) decrees above that line. i '2 ) The patient Ivmu' face down upon the plate; the tube over the back of the head < Fiii. t>~M. Ileid'- line should l>e vertical and the tube 2o decrees above it . J The patient lyiim' fact 1 up: the tube under the back of the head; the plate over the face. Reid's line should be vertical and the tube 2:-! decrees a! > ive it . 1 The patient lyin^ on liis siile upon the author'- lateral ])!ate- holder, which hold- the plate in front of the patient's face; the tube 971 AND KONTCKN HAYS behind the head. Heid's line should be used as a guide for the posi- tion of the plate and the .r-ray tutu-. The Nj iic ] )late-holder by the vertical i Fitr. tiso i. If a pre- ; ' iS'J i- necessary, the e can ever tret ill flilol'o- ise of ni'otective tl TIIK .T-RAY Care should bo taken that the median piano of the patient's hoad is horizontal. A little pad may be placed under the side of the neck. Fig. GNO. Radiography of tho frontal sinus, employing the author's lateral plate-holder. As the antrvim is also included in the picture, it is the author's custom to have the patient hold a cork between his teeth. The landmarks of the upper jaw are clearer if the mouth is open. (ML:. HM. - Fluoro.-i'opy of the frontal >imir- pn-liininarv to rudiotrranhv \\ith tli Allusion has been made to the stereoscopic plate-holder. It is eldom necessary in make a stereoscopic radiograph in frontal -inn cases, Ian it i- sometimes (.lesiraltle t< change the plate if we suc for Frontal Sinus Rail/ii-f tube -hield i- a clinometer, or measurer of . made from ;i dock dial with a -ingle hand freelv pivoted . ueihled. If the hand i- at (i o'clock when the long axis vertical and the central ray hori/ontal, then the ul ''. time minute- from 1 he (i o'clock mark the cent r; 1 1 ra v i- inehned at an angle of about '2'-\ decrees. i I;K .r-KAV Fiii. GS4. Author'- frame applied to the head to indicate the median plane for sinu iX MKiurAi. i:i.i:n KHITY AND KONT<;KN HAYS The technic is to place the patient's head in the right position, fasten the tube at the proper angle of inclination, adjust the height and distance of the .r-ray tube, making use of tape measure, as in Fig. 683. When a woman'.- face i.- against the plate her hair often makes it difficult to see jn.-t \\here the median or sagittal plane is. The author's whalebone frame previously applied to the head facilitates this. Tin l)/x(. front //n Tulu to (he J'late. The selection of the distance is influenced by two considerations: first, that a short distance will give a better picture and in a shorter time than a long distance; and, second, that too close proximity to the back of the head with so long and strong an exposure may produce alopecia or dermatitis 30 inches is the author's recommendation. ( 'aldwelP u>ed at one time a distance of IX inches from anticathode to plate and all exposure of twenty seconds. His article did not state what interrupter he used, but it is supposed to be a ('aldwell. "With a certain interrupter and coil, with the rheostat resistance all out, a reading of 10 milliamperes shows that the penetration of the tube is about high eiioiiizh" i ( 'aldwell I. Tin Ti cbnic of the Exposure. These pictures present such difficulty that the author will repeat here some of the general details as to technic which have already been described elsewhere. With a 12-inch induction-coil with a ('aldwell or a Wehnelt in- terrupter, and a rheostat in which the resistance is afforded by different strips of metal, the interrupter is regulated to give a current of 11 ampere- with the ('aldwell or If) to 22 amperes with the Wehnelt inter- rupter, and some resistance is used while the vacuum of the .r-ray tube i- regulated to the proper degree. This should be such a degree that with all the rheostat resistance cut out the tube will back up a parallel .-park of f) inches. The milliamperemeter should indicate the pas- sage of x or 10 milliamperes of secondary current through the tube. The penetration of the ray .-hould be about X Benoist. The use of an unfluctuating converter or of a transformer and the ( 'oolid^-e Kadiator tube permits of a current of about (If), 000 volts and about 30 milliamperes as the best routine factor.- for this work. The tube should have a penetration of \o. (> or <'//, /,/Y/,y m .- This is absolutely essential with a gas-filled tube; -1 results are obtained with an orifice 1 ' inches in diameter. A ' 'hragm may be used or t he ant hor's contact diaphragm (p. 801). '< -hould be rapid and have good density. Such a plate as .-ray plate i- suitable. Or such a film as the Kastman du- -ray film. The Paragon screen plate gives good results with an in srjven if care is taken to avoid overexposure. An intensify - 11 -hould always be used. the absence of secondary radiation from the gla-s wall of the ' ibe makes a -mall diaphragm unnecessary. The author with it bccau-e of the increa.-ed difficulty. of posit ion- vtube. And in many radiographs embracing the entire head ''ii of the frontal -inu- ha- been -o good as to make it appear iry rays from the ti--ue- of i he head were not a mate- lor with a ( 'o( ilidu'e 1 ube. /.<,">. 'in . Thi- varie.- from a traction of a second to online to the apparatus and the quantity of Tin: .r-u.\Y 079 power employed. Six and a half seconds would lie correct with 5- inch spark, '.'>() milliamperes, oO inches, man weighing loO pounds. It would he a very serious mistake for an operator with a powerful apparatus to try to overcome errors in technic or relative position by giving long exposures. There would be danger of dermal it is or alopecia. The plate shows very much better than the print in all radiographs of the accessory pneumatic sinuses taken in an anteroposterior direction. It is to be examined in a perfectly dark room by means of a negative examining box. The latter has a framework which receives the plate, behind which is a sheet of opal glass lighted by a number of incandescent lamps. The degree of illumination is regulated by a rheostat. The most brilliant light does not always show the picture to the greatest advantage. In the absence of a negative examining box such a plate may be studied in a darkened room. The plate is held up between the observer and a sheet of white paper, upon which a fairly brilliant light is thrown. These plates are usually not strong enough to show well if held up in front of an ordinary electric light. The plate may be treated, as suggested by Caldwcll, to accentuate the important portion of the image. A square of sheet lead, together with lead numbers and lead letters spelling the words riyht and left, is placed over the central part of the plate after the exposure is com- plete and the plate removed from the patient. A convenient plan is to have all these permanently mounted on a cardboard XX 10 inches, and simply have to change the serial number of the plate each time. This contrivance being in place, a short st rong exposure of a few seconds is made. As the plate is being developed t his full}' exposed border comes up and materially assists in the observation of the process of develop- ment by the ruby light in the dark room. The dense black border produce* 1 on the finished plate brings out the useful part of the image more clearly when the plate is examined by transmitted light. A radiograph of a probe in the frontal sinus is considered by Douglass the only certain proof of its entry into the sinus. 1 A metal tube passed up through the infundibulum has shown very well in a lateral radiograph by the author; not quite so well in an antero- posterior one. Jack, at the time of reading his article, 2 regarded the value of the: .r-ray in frontal sinus diagnosis as still xnl> ji/icc. Radiographs made for him had not proved successful. Mosher' reports the successful employment of the radiographic method of examination in sinus disease. llarland and Pancoast believed, at the time of reading their report at the Annual Meeting of the Medical Society of the State of Pennsyl- vania. Sept., IHOli, that a high degree of vacuum and very great electric power were required. The}" used all UK luct ion-coil with (iO amperes ot current through the primal'}- coil, a distance of Hi inches from the anti- cathode to the plate, and an exposure of ten to twenty seconds. 'J Ins is a 1 remendouslv powerful current . The}' made their pictures with the tube belo\v the level of the occiput. The}' used a diaphragm. (Tver's dissections of the frontal sinus" 1 show a very great diversity i:i.!:rn;i( ITY AND HOXTCKN RAYS outlet-. Such variation- \vnuly anteropostorior radiograph. I-'iu'iirc< tis.") and fiSti show variation- in the noi'inal appearance in ' - 981 n Transillumi nation of the Frontal Shuts. This must be done in a very dark room. A 3 candle-power incandescent lamp is enclosed in an opaque cylinder, whose open end is pressed close against the under surface 1 of (he upper wall of the orbit. A red glow may be seen defining the extent of the frontal sinus. The glow may be lessened when the sinus is filled with solid or liquid substances instead of air. The diag- nostic value of the method is impaired by the fact that some sinuses, con- taining pus or swollen or polypoid mucous mem- brane, show apparently normal illumination, and others, which are perfectly normal, do not illuminate as well as usually. Sometimes in a normal case the two sides show unequal illumination. Radiography of the Antrum or Superior Maxil- lary Sinus.- r [ his accessory pneumatic sinus may be examined by the .r-ray. either fluoroscopically or radiographically, from several different directions. (1.) The tube may be at the affected side 1 of the face, and the fluoroscope or photographic film may be held inside 1 the 1 mouth, either in a horizontal posi- tion or applied as closely as possible 1 to the inner surface of the 1 gums and roof of the 1 mouth. The image shows whether the antrum is of normal size, whetheT it is rilled with pus, polypoid, or tumor tissue', and whether any of the 1 teeth projee-t into it and cause 1 trouble 1 . The details of this examination are 1 explained in the scctiem on .r-Kay in Dentistry. (2) The 1 tube may be 1 at the opposite side 1 of the face, the 1 mouth open, and the ray shining through the 1 mouth from below the level of the opposite teeth, and having to penetrate only the roof of the mouth and the 1 upper jaw on the 1 affect eel siele 1 . The fluoro- scope 1 or photographic plate 1 is held against the 1 outside of the 1 fae'e 1 on the 1 affected siele 1 . A comparison be 1 - txvee 1 !! the 1 two antra may be thus obtaine'el. The quality of the 1 ray required is about Xo. (> Benoist. A much greater degree of penetration does not afford sufficient shadow to even make 1 out the 1 roots of the teeth clearly with the 1 fluoroscope; 4-inch spark, 30 ma.. 23-inch distance 1 , no intensifying sciven would require abend five 1 seconds for a 150-pound man. (3) The 1 tube may be at the' oppeisite side 1 of the face 1 , in a' line passing through both antra from siele to siele. The plate is against the affected side of the face. This position is ve'rv easilv maintained bv the patient if he lie the 1 aftecte'd siele' distance 1 should 30 ma., for four 150-pound man SIX')!. Figure liSS shows the ant rum forming the 1 natural air space above tin 1 level of the hard palate 1 and crossed vertically by the malar promi- nenco. n the table with the plate under f the face and the tube over the opposite side. The e about 30 indies, the -park equivalent 5 inches. econds or any other 120 ma. second exposure for a ith an intensifying screen (see Exposure Table, p. i, Ki.KiTiuriTY AND UONTCKN HAYS I'iir. liss. Normal antruir, THE .T-RAY OSS Figure 689 enabled the author to make 1 a diagnosis of suppuration in the aiitruin. The case is further figured on p. ( .)S1. A radiograph made in this position does not give a comparative picture of the two sides. An important fact is that the shadow of an opaque substance in either antrum would he cast upon the plate, no matter whether it was on the side next to the plate or not. Generally it is only one side that is affected and no doubt exists as to which side. The shadow of the opposite ant rum if normal offers no real difficulty, even though it is superimposed on the image of the affected side. The hitter is dearer and of the natural si/e, while the former is enlarged and vague because of its distance from the plate. It is to secure the last con- dition that the tube is placed as does as practicable to the unaffected side of the face. Figure 090 is such a radiograph of the antrum in an Fiji. 690. Normal antrum in empty skull (filled with shut on one side). empty skull. Placing the re-ray tube somewhat further back enables us to secure separate images of the two antra in a lateral radiograph. Cases occur in which it is necessary to make a comparative picture of the two antra, and then the following method is generally used: (4) The tube is behind the patient's head and in the median line, the plate being in front. The relative position recommended for ex- amination of the frontal sinus answers very well for the antra. The frontal sinus, ethmoid cells, and both antra often show very well on the same plate. The antra alone are somewhat better shown in a radio- graph made with the chin somewhat flexed toward the chest and with the tube at such a level that the shadow of the occiput falls above 1 the antrum. The antra show better when the tip of the nose is pressed right against the plate than when the forehead touches the plate. Tliis position may be obtained in any of the ways mentioned on pages 973 to 97t> in describing anteroposterior radiography of the frontal '.S4 MF.im'AL KLKiTKHlTY AND Iii)NTGEN HAYS ..inns. One of the best hchm with the author's lateral plate-holder, the patient lyiniron hi- side: and the other with the patient lying face down upon the plate. Tliis picture i- less difficult than the anteropostenor one ot the fiontal sinus, hut at the same time is far from easy. At a distance of Winches, l-im-h spark e(|uivalent, oOma. for four seconds with an intensi- fviim screen, <>r any other 1'JO ma.' -econd e: sl . ( . \''rin:il fniiiKil -iiiii-: '- und "', normal ethmoid Radiography of the Ethmoid Cells. The ethmoid cells lie between r wall of 1 he l \v< > orbit - and t he upper part - of t he na-al fos-a'. ethmoid cells -how in either an anteroposterior or a The po-terior ethmoid cell- ean be -tudied be.-t in ["mure- o'.rj and o'.Kl -how the po.-ition of the ' hmo - in an empty -kull. examination i- made u:;h the plate in trout. e In ad. and may be above the occiput at the same t hi frontal -inn- or beli iw t he level < if t he ' ' t ion- for t lie ann-um, The rh< lice of p< >-i- ' -; .' : the in 1 /' ih i 'nii-lil i- -Uppo-ed to extend to THK .r-KAY Fit:. O'.L>. Middle ethmoid eell< full of lead. Lateral . /; S:- / -*?. I'iL'. H'.I:;. -M: Mli' eimnoid cell- fi;ll nf 1. id. Frontal -' u- :u i] iintniin In natural con () inches from the anticathode to the plate. Five- inch spark. (')") kv., oO ma., four seconds, or any other 120 ma. second expo-tire for a 150-pound man. I ' ' ' i ( '1 ironic Mippurat ion in ant rum and otnmoi iput . 1 his is practicable only for the antruin. Radiography of the Sphenoid Cells. These are studied in a lateral radiograph made in the same manner as that of the ethmoid cells. Figures ti!'." and (> ( .K> are radiographs made of the sphenoid cells in an empty -kiill. They show the relation of these cells to the normal and -hadows of the adjacent parts. Tliey havi 1 served the author i na 1 1 in MC charts. In a radiograph of an actual patient a certain dark shadow was n correspond \\itli a natural bony shadow in the chart and not po-ition of the air-space forming the sphenoid sinus. The \va- thai thi- -inns was not filled with pus. i if tin , jiln nniil shows beautifully in a case now under treat- . cross-fire. The siti'lit of one eye had been lost before, thf .--. : in. The tumor now seem.- somewhat smaller and Til 10 X-RAY 087 the vision in the other eye which was badly impaired has become normal. Finn/ in the Sphenoid Cell*. Previous radiographs h;id failed 1o show any abnormality in spite of the fact that a cupful of fluid ran from the nose in five 1 minutes. The author had the patient hold her head perfectly upright for half an hour, a sufficient length of time to ensure the sphenoid cells beiii"' full and, without change of position, made radio- graphs lateral and anteroposterior. The former especially showed an opaque mass instead of the air space of the sphenoid cells. The fluid was eerebrospinal fluid and the patient died of meningitis. Stereoscopic Radiographs of the Pneumatic Sinuses of the Face. Stereoscopic radiographs of the sinuses may be made by havintr the tube 1?, inches to one side of the median line for the first plate, and the same distance to the other side for the second plate. The anteroposterior radiographs of the frontal sinus require so lonjr and strong an exposure that the double length of exposure 1 required for stereodiaiiTaphy is usually undesirable. There is not the same objection to the stereoscopic method in lateral radiographs of the frontal sinus, the ethmoid cells, and the antrum. The Turbinated Bones and Septum Nasi. The turbinates show in any of the anteroposterior radiographs of i he face. Their si/e and shape are shown and the extent, Lo which I hey encroach upon the nasal pas- MKDU'AL ELECTRICITY AND KONTGKN KAYS >ages. Deviations or old or recent fractures of the septum are well shown. Topography of the Pneumatic Sinuses of the Face as Shown in Radiographs. The author exhibited at a meeting of the Rhinological and Laryngological Section of the X. Y. Academy of Medicine, Novem- ber. 11H)7. a series of radiographs of an empty skull in which one or oilier of the >inu>e> \va- lilled with lead shot. The radiographs were made in either ; lateral or an anteroposterior direction and some of them were stereoscopic. The value of such pictures lies in the guide which 'hey atlord to Mie recognition oi the dilteren! Amuses in radiographs lll.'lde ffl Mil :icl I);, 1 j i;| 1 jellt S. Some of i he-e r;tdio<_M'a phs are reproduced in Fig>. W2, ti'.'M, (i!)."). and 1 1 ' > 1 1 THH NETK e\;iniiii.'ii ion of the neck i- rather inconvenient. i>uf ii'e-ence iii loreiii'ii liodie< or lunior^. Fractures ot < ' i K i!< 'iile ch;inij.e> in tlie |;ir\'HX are much lietler '!. i hei'e i.- a ca.-e on record of tlie imaiie of THE X-RAY 089 the cartilages of the larynx being mistaken lot 1 a set of false teeth operation, death, teeth not found in the patient'.- throat, hut subse- quently discovered in his bed. Lateral Radiography of the Neck.- In radiographing the neck from the side the patient i- -itting up, the plate i- at one -ide of the what elevated, so that the body of the jaw is horixontal. The tube i- on the opposite side, at a distance of '2-\ inches from the ant icat hode to the plate, and about \ inch below the level of the chin. The resist- ance may be 4 inches. .V> kv., o() ma., twelve -econd> without an in- tensifying screen, or 10 ma., thirty-six seconds, for n 150-pound man 'see Kxposure Table, page SOl)). It may very well be found that the plate 1 pj,_r. 007 Lateral r;ioral bone. An unusual amount <>f ossification in the thyroid cartilage i- said to have caused it to be mi-taken for a set of fal-e teeth in the case referred to aljove. Broken Neck from Diving.- One case with paraplegia, examined by the author for Or-. Howell and Front, -howed in the lateral radio- uraph a frarture of the fourth cervical vertebra and a dislocation tor- ward of the fifth. Tin 1 anteroposterior view wa- not of much >ervice. Recovery followed manipulative replacement and immobilization. MKDICAI. TKKITY AND H<")XT(;KN IL\YS Another ca-e showed no displnoomonl MIK! death occurred many months later. An anteroposterior radiograph of the neck is mad" with the patient lyiim- fare up on the table, with the plate under the hack of the neck, and the tulie vrrti'-dly over the cricoid cartilage. '1'lie distance is '2-\ mrhe< Jrom the anticathode to the plate and the exposure the same as for the anteroposterior radiograph, Figure (> ( .)8 is of a patient whose larynx had lu-en removed for carcinoma: the tracheotomy tube is wn. Cervical Ribs. The anteroposterior position i> the correct one for ntfln-'itiiniy tulic in position after or tiii- condition. The distinctive appeai'ance in this , h ;i Hipeniumerarv ri'h iloe.- not extend around to .i <:.. li .' form.- a short -irai^ht lione. A -nod raih.o- ;i1e ;i ci : \ U'al I'll) \}'< i!n 1 he t I'ali-ver-C I'll!':,. \\herc it is quite rudimentary, however, it is f he symptoms <-om] of. ft ni 1 lilat era!, ari M rom 1 he seventh cervi- , mei'a ry nl > may 1 more < leveloped than idiment a !-, ( ; I- < -i 'lit any form bet ween rili. The et'leH ~i 'I'ii ins \\ hrn the TIIK .f-KAY 901 and nerves pass over it. The symptoms as summarized by Keen' are: 1, There may be a hard tumor in the neck with a high and obliquely pulsating subclavian artery: 2, there may be severe neuralgic pain, per- verted sensation, and hoarseness: '.*>, there may be thrombosis in the subclavian artery, gangrene and edema of the extremity, and a sug- gestion of aneurysm; 4. there may be wasting of the muscles of the arm, dysphagia, and scoliosis. Rotary Dislocation of the Atlas.- This comparatively rare, but not necessarily fatal injury may be diagnosticated by a lateral radiograph of the neck.- Forward Dislocation of the Atlas. Forward dislocation of the atlas with fracture of the odontoid process of the axis is the lesion which the legal hangman aims to product 1 , and which usually occa- sions such compression or laceration of the spinal cord as to cause practically instant death. A lateral radiograph of the neck demon- strates it. 3 Fracture of the Cervical Vertebras. This will show in an antero- posterior radiograph, but a lateral one will usually be found more desirable. Localization of Foreign Bodies in the Tissues of the Neck. Stereoscopic radiography, either lateral or anteroposterior, gives in- teresting results in localizing such foreign bodies as bullets. Localization on the McKenzie-Davidson principle is valuable in the same class of cases. It is much simpler, however, to take two radiographs of this region at a right angle, first fastening a lead marker on a part of the neck where its image will not cover that of the bullet which is located in this way. The same thing may be accomplished with the fluoroscope. The neck is examined at first from the side, and a lead marker is applied at each side of the neck in a direct line with the bullet, as seen in the fluoro- scope. Then the fluoroscope is held behind the neck and the tube in front while another pair of markers are applied. The intersection of these two lines is readily found by the surgeon if the different marks are made durable by nitrate of silver. Localization of Foreign Bodies in the Esophagus. These are very apt to be metallic, and if of considerable size, like 1 a e-oin, should be easily located in any part of the esophagus. One 1 glance 1 at the fluoroscope will generally reveal tin 1 presence and position of the for- eign body. This was the 1 case in the author's own patient, whose radiograph (Fig. (>99)was taken simply as a record. The- nickel five- e-e-nt piere 1 was removed by a coin-catcher passed down through the mouth withemt waiting for the 1 photographic plate 1 to be 1 elevelope'd. A good deal of twisting and pulling was required in this case, as the- coin had been in position for nine days and had begun to ule-erate through the wail of the esophagus. The 1 utmost gentleness had to be' used in the-se 1 manipulations, and it required five 1 minutes to remove 1 it after it was en i:\-igi-d in the coin-catcher. This instrument, it will be remembered, is a sort of blunt hook hinge'd upon a flexible handle, and is passed beyond the coin and then withdrawn. When it engages the coin, the latter is brought out by pressure applied ;,i its most distal part, and the 1 coin 1 Amor. Jour. Me.i. Sciences, Feb., 1'.>7. -Corner, Annul- of Surgery, .Ian.. I'.'OT. :i I\cllv, Ilii,!.. Auiru-t. 1 '.'<>'">. MKDICAL KLKiTKICITY AM) RONTOEN RAYS may tip in one direction and tear the wall of the esophagus if it catches in a depression caused by ulceration. Such an accident is to be avoided by livntleness and by twisting and turnin. If the coin refuses to move the coin-catcher should be freed from it by pushiim it back and then lunimti n into a po-ition in which it -lip- pa-t the coin and out o! the pat lent 's inoiit h. The ne\t -tcp in -udi ;i c-.i-^c would be one \\lnrli |]i|u-|it liaVC beet) u-ed in the bemnnmji extraction by torcep.- under liuoi'oscopic ob- servat ion. The position of the coin is first ascertained by the fluoroscope and the esophaiieal forceps arc then introduced. Ay;ain the fiuoroscope is used, and the coin sei/ed Ii\- the l>|;ules of the foivep- under (lirect observation. Traction is then made, and as it i- exerted upon t!ie proximal part of the com the latter has no tendency to honk into t he esophageal wall. Ilenrard 1 has devised special forceps for tin- particu- lar case. \o harm is usually done if a coin lodged in the esophagus is pushed into the stomach in the course of efforts at extraction. Jf a com or aiiv other foreign bodv cannot he detected by the fluoro- scope a radiograph should he made and developed at once. A com or other foreign hod\" \\ p hich has been located in the esophagus by an .c-ray examination, ami which has resisted efforts at extraction through the mouth or dislodgmenl into the stomach, usually requires esopliagotomy. This is so serious an operation that the radiologist should uuard against everv possible source of error in making his diag- nosis of the presence of a foreign body from the ./'-ray appearance. A most striking case in this connection was that of a patient who was supposed to have swallowed a set of false teeth. The radiologist thought he could see them and an csophagotomy was performed. The}' were not to be found in t he pat ient 's esophagus. The pat i cut di'-d from the operation, and the false teeth were discovered under the pillow in his bed. The explanation given was that some part of the larynx was unnaturally dense, and that its shadow had been mi-taken for that of a foreign body. The hyoid bone, especially its cornu in a lateral view, presents a shadow which might be mistaken for a foreign body, a misplaced tooth, or a salivary calculus. .Needles or pins are sometimes easily detected and sometimes do not show. A case of this kind which the present author examined was that of a circus pel-former and sword swallower. He was in the habit of swallowing needles, which were probably caught in some kind of recep- tacle out of sight in the esophagus. After the performance ihis recep- tacle was to be pulled up out of t he man's throat. < >n a cert a in occasion some of the needles were supposed to be missing, and a few days later the author made a radiograph of the thorax, which did not reveal them. Fish bones and small chicken bor.es would UsUailv not show in a radiograph of the thorax; they might if lodged in the 1hro:it . Reetemvald- removed a silver quarter dollar located by the .r-ray (radiograph bv Johnston) -I 1 .' days after lodgment in the esophagus. Hannecart 3 located a hard-rubber dental plate which had been al- lowed to remain in the esophagus for ten day-, the medical attendant having been deceived bv the tact that an esophageal sound could be pa --I'd wit hoi it obstruction. Esophagi >t om v was successfully performed. The foreiun bodv had caused a peri-esophageal abscess and a necrotic condition of the wall of the e-ophaiiu-. but no dyspnea. Scatinell' reports a case of ,r-ray localization ol a toivmn body lodii'ed in the esophagus for seven week-. It was successfully re- mi ivet 1. i I,c R.-nlinm. Sopl |."i. 1, p :!0'J - Nru V,. r k Mr,| ,],,.i r . ,l ; n i:i. I'.'in;. : l.:i IJcVlli' ill' StnliKiti.l'tui' . M :, \ . I'.HI.Y UoM.m MM. ;ui ' -7. 1' 094 MF.niCAL KI.KCTH1CITY AM) KONTCKN KAYS King 1 located a child's tin-whistle lodged in thr esophagus for ten days. Ksophagotomy \vas successful. A pin hidden in one of the ventricles of the larynx would he readily shown by a lateral radiograph, though undiscoverable by the laryngo- -cope. Mackintosh and Downie have reported such cases. The author knows of a case in his own family where a pin escaped detection by the laryngoscope and caused cough, persisting for two years. It was finally dislodged by a lit of coughing. The .r-ray, if it had been known at that time, would probably have discovered it. Other foreign bodies, such as pins and metal washers, have been located in the esophagus by means of the .r-ray and successfully re- moved. - Stricture of the Esophagus.- The .r-ray study of this condition may be done by the use of a flexible bougie with a metallic olive-shaped extremity, or. according to a suggestion by ('handler, 3 two such olivary bougies may be used. One may be pushed through the stricture and then withdrawn until it engages behind it. the oilier being pushed down to the face of the stricture. The radiograph would show the position of the two olivary tips and the distance between them. An anteroposterior picture is made witli the plate behind, and using the same technic as in other neck or chest radiographs, according to which region oi the esophagus is affected. There is every! hing to be gained by fluoroscopy during the extraction of a foreign body from the esophagus, provided that one is exceedingly careful to prevent overexposure. The patient should lie face up on a canvas or thin wood table, with the .r-rav tube underneath. The room i- entirely darkened, and the image of the foreign body and the forceps oi 1 coin-catcher are observed upon an open fluoroscopic screen laid over the patient 's neck and chest . The danger to 1 he operator would be verv great if such cases occurred frequently. The .r-Ray Diagnosis of Diverticula or Stenosis of the Esopha- gus. This is made by means of radiographs taken after a patient has swallowed an emulsion of bismuth, or a paste made of potato and bis- muth, which shows perfectly black in the local mn at which its progress i- arrested. The bismuth or iron emulsion for radiograj ih v of the esoj)hagus should form a thick liquid. \ thick paste of in a. -lied pot at o and bismut h or iron is preferable to tin li'iuid fi >r rai liographic purposes. The proper position is that the patient lie flat upon his back on the plate, with the nibe vertically over the portion of the esophagus which !.- MISpected to be the seat of the lesion. Spindle-shaped Dilatation of the Esophagus. This condition ha- bi'en diagnosed by Sjomvi.i - ; in leases. One patient was fourteen ninth.- (,M. and was mven three or lour t easpoonfuls of an emulsion : ing s grains nl bismut h subnit rat e. A lateral ra< liograph showed '!.'-' i ph. 1 1 in i- a.- a narrow ribbon (visible because of a < Iherence of part i- : bi-muthi down to the level of the eighth dorsal vertebra. There : . became large and dense in a spindle .-hape. An antero- THE T-RAY 905 posterior radiograph showed the spindle-shaped mass, but not the traces of bismuth in the upper part of the esophagus. The other patient, a man of thirty-seven years, was given 00 c.c. of an emulsion containing 25 grams of bismuth subnitrate. A lateral radiograph showed a spindle- shaped shadow beginning at the level of the seventh dorsal vertebra. The dorsal radiograph showed everything but the upper end of the shadow where it was overlapped by the heart and vertebra-. Stenosis of the Esophagus Due to Pressure by Mediastinal Tu- mors. Two cases of this nature were diagnosticated by Barba 1 from .r-ray examinations, aided by the passage of a sound filled with a con- centrated mixture of bismuth subnitrate or provided with a metal stylet. Retropharyngeal Abscess.- This is a condition the diagnosis of which may be assisted by a lateral radiograph of the neck. A clearly defined area with its convexity forward is traced behind the tract of the esophagus and of the larvnx or trachea, but without marked differ- ence in density from the surrounding tissues. A Tumor of the Neck is Diagnosed in a Similar Way. ( lenerally speaking, the differential diagnosis between a tumor and an abscess in the neck by means of the .r-ray is not so much a difference of density as in the shape and position of the tumor. Fig. Sll. p. 1228, is a radiograph taken of a patient under treatment for recurrent carcinoma of the neck. The original growth was in the larynx, and a complete laryngectomy had been performed about a year before this picture was made. There was a recurrence of the cancerous growth in the tissues of the neck, forming at the time that he came under treat ment a mass about the size of a small apple, and occupying the position from which the larynx had been removed. The patient was still able to breathe through a trache- otomy tube, but the growth had com- pletely obstructed the esophagus. The results of .r-ray treatment in this case are described in the chapter on "The Thera- peutic I'se of the .r-Hay." The picture -hows thi- growth as a portion of the tis- sue, not differing in density very much from the other solid tissues of the neck. It show- the air-space of the trachea ter- minating suddenly at the level of the growth. No trace of the original carti- lage- of the larynx is to be seen. Radiographic Diagnosis of Laryngeal Lesions. It i- very important to have a radiograph of the normal larynx taken with one's own apparatus and technic as a m<'an< of comparison. A chart showing the location of the different cartilage-; and other part- of this -ection of the neck is given in Fi:',. HKl',. 1 1.;. .00. -] )i;i^r:un of anpear- 1 nl' the larynx in :i lateral radio- :.. //, I'.ody of hyoi.l bone; rnrnua of hvoi.l hour: /;, epi- : '/', upper ciininu of thyroid I'.-irtilajit 1 ; A", prominence of larynx : '/''. trachea: I", ventricle of larvnx iaitcr t ;ra H< >.\T< i KN KAY The late Dr. Ka->al>ian : reported radiographs .showing tumors of the t rachea and vocal cord-. THE CHEST Fluoroscopy i- of ureater value in examination of the chest than almost anywhere el-e. The relatively sliirht density of the lun^s and the thinne.-- of the chest walls permit sufficient radiance to pass through to uive a liood imasz'e on the screen. Fractures, or disease of the clavicle or ril>-, are readily detected; those of the vertebra*, and e-pcrially of the -termini. being more difficult. The condition of the him:'- i.- very well studied in this way with a (i-inch spark equivalent and ." ma., the anticathode lieinji \~i or L'O inehes fi'om the c'liest wall. (her in front or liehmd. In an entirei\- dark room, and with .' flilnrcsceiil -creen. the mo\'ement- of liie diaphragm may lie ' . al-o 'he I ? - aii.-liic('iicv of the luni's. and a diminution of the '' indicate- con-olidat ion of the lunu or ihieken'mn- ,f the pleura: iii the |MH C _! a!-o -how, and in many case.- thickening of the the hroiichi and deposit- in the l\mphatic vessels and Pleuritic effu-ion or emp\ema ma\' be determined in this IIH -mailer enclo-ed fluoi'o-cope ha- the advanta.ue of liein^ - i! i'- iii -.-en icnl to da rken t lie room complel elv. N- x . ! . M .! .I'.ur.. IM 1, L':i, I!i7. . >7 I .<. A prolonged study of the fluoroscopic image is dangerous to operator ;nid patient. The heart cut) IK- distinctly -een ;ind each puls;it ion \v;it died. it is often desirable to estimate the si/e of the heart with an approach to accuracy, and for thi- purpose the ort liodiagraph is of service. One model is illustrated in Kig. 702. It consists of lube-stand and fluores- cent screen-holder combined in such a way that they move simulta- neously like the prongs of a pitchfork. At 'the center of the lead pencil which, when the screen is moved, make of paper which is held in a fixed po-ition. The 1 ween t he .r-ra t ube and I he image of t he upper par! of I he heart appears to be at 1 he center o! t he screen it means t hat I he t ube and t he upper border of t he heart and t he lead pencil anxill at the same level. A mark made there is actually at the level of t he upper border of the heart. In t he same way the act ual level of the lower border may be marked on the paper, and by carrying the screen and its pen- cil along the visible 1 border of the image an outline is drawn which is of the natural -i/e. Thi- is true in spite of the fact t hat t he heart is at a consider- able distance from the screen, and that consequently its visible image at any stage is enlarged in proport ion to its distance from t he plate. The t racing consist s. I hen. of a number of points rep- re-enting the true po-ition of portions which they represent on 1 he 1 lorder of t he heart . A con- vincing demonstration of this i- !< > place a key rat her clo-e tot he paper and another of the same ., ,1.,,,^-rous wp.^ur.. nf'the operator and si/e much further away and patirnt. quite clo-e to the .r-ray tube. The fluoroscopic image of t he first is of about the true size, while that of the second is great ly magnified, yet, on pa --ing t he pencil around t he borders of the two image's, both tracings are found to be of the same si/e. and that is the true -i/e of the keys. The ort liodiagraph does not usually provide the means for making a radiograph -bowing the true si/e of the heai'i : the re>ult obtained is only a pencil tracing of the orthodiagraphic image. The apparatus may be arranged so that the tube is under a table on which the patient lies with the paper and screen above him. The present a ut hor made early experiments looking toward the discovery 90S MKDU'AL ELECTRICITY AND RONTGEN KAYb cellular screen, the principle being- that the x-ray is allowed to escape only through a group of nine parallel tin cell/,, each -\ inch in diameter and ") inches long. The tube is enveloped in a localizing shield in the orifice of which the group of cells is fixed. The whole is suspended by a cord long enough to permit of motion in everv direction far enough to !'!. 70:5 Orthodiagraph with t\v< cover the entire organ to be depicted, and permitting the group of cells to remain vertical all the time. The plate lies ilat upon a table, the portion to be radiographed on top of that, and the tube is suspended just high enough not to let the end of the cellular screen touch the flesh. As not more than a square inch of the plate receives the rays at one time, the duration of t he exposure would have to be as many times longer than normal as there are square inches in the picture desired. This does not mean that the patient is exposed to the .r-ray an abnormal length of time. Kach square inch of the required area of the patient receives a normal exposure. Naturally, one would make the picture much more than the dimensions required to show the actual si/e of the organ or foreign bodv under examination. The image of anv very small object, like a needle, is more blurred by this method than by ordinary radiog- raphy. A variation in the ort hodiagraph has been suggested by (Irocdel. 1 Tl consists in placing the paper and the crayon behind the .r-ray tube. Tin- enables one to place the fluorescent screen directly in contact with the patient. There is only a small metal pointer, which moves over the surface of the screen and does not interfere at all with an accurate view 1 Munch, incd. \Vorh., 1'KMl. THK X-RAY 909 of the* image. The crayon is in a line continuous with the normal ray. One form of orthodiagraph 1 lias two screens (Fiji. 703), one for the orthodiagraphic tracing, with a small diaphragm in front of the x-ray tube, and another for a general view with the diaphragm removed. This may be used to make an ort hodiagraphic radiograph by first making a tracing of the heart and the general landmarks ot the chest without the small diaphragm. Then applying the latter and putting a photographic plate in place* of screen Xo. f> (Fig. 703) carry the pointer over tin* same* pencil lines again. Orthoeliagraphy is very far from being indispensable. An ordinary radiograph, made with the tube at the proper distance from the plate to i inches, and in a man of 1 Knnmen ( 'nntrress, May. 1.">, exhibited by Polyphos Co. 1 I II II I about h~>!) pounds >(> ma. tor thirteen .-econds or any other equivalent < >f :>!Mi ma. seconds' i-xposuri 1 . The-e different expo.-ure- .irive equivalent re-ults upon a photographic plate, the patient lyinir on his hack upon the plate, and the tulie at a di-iaiice of 2M inches from anticathode to plate. Shorter exposure.- under the same condition- will produce pic- tutv- \viiich are very tiood. Uit not quite so sul)stantial appearing. For t he detail in t he 1 in ILL- I prefer 4 -inch spark and .'! ( ,Hl ma. seconds, and the reMiit may l>e tie>! uhtained if the picture is taken in so short a time that the patient can hold hi.- lnvatli and the chest !>e motionless during the entire expn-ure . To obtain still inoi'e rapid pictures of the chest an in- ten-ifyin^ screen may he used. The exposure may be reduced to a snap- -hot . fust ant alieoiis radiography of t he clie-t ha- been attempted in tin 1 -en-e in \vhich the t erni m-t ant aneous i.- u-ed in rc^a rd to snapsliol jihoto- uraph- with a kodak camera: and with an extremely powerful apparatus p. 7!7 one-i jiiarter or one-hali second excellent expo-ure,- are practic- vithoul an inlensifviny: -creen and o| one-third that time \\itli a -i-feeji . l:i vadiotira|)hiiiLL the che-1 the lx-1 picture- are obtained with the lowi -' deu;ree of vacuum which will -how dearly through the chest with the - : o-cope. Sudi a \'aciium will take a linle longer lo produce a pi<-1 . the result will lie both better contrast and better detail t han wil h , hiiiln-r va 1001 .\neiiry.-m n[ i he aorta shows very well in a radiograph and so do lep'tsits in the mediast inal L;!and> ami foreign bo. lie- in the esophagus and hi!i'_rs. I "> y allowing ihe patient to -wallow an emul-ion of bi. mull) or iron, which i- very opaque- to the .r-ray, we may demons) rale the pre-ence ot a divert iciil n n i of a hra' are best studied in a radiograph made with the tube ) inches to one >ide of the meihaii line, so that the shadow of the sternum will 1 all to one side oi that of the spine plat e behind, t ube in front of pat ient . The Diaphragm. Diaphragmatic paralysis is readily detected by means of t he .r-ray. 1 Commencing pulmonary tuberculosis is indicated bv diminution of translucency at one apex and lowering of the corresponding half of the dia j (hragm.- The convexity of the diaphragm in its average ])osition on the riidit side is Kil centimeters below the horizontal episternal line, and 1^1 centimeters below this line on the left >ide. The amplitude of move- ment is the same on both sides, and is about IN millimeters. The relation between the amplitude of excursion and the functional an.ule of the ribs varies in different normal individuals, according to the respira- tory type. The conditions in the amplitude of excursion on either .-ide may have a pathologic significance. 3 Reduction in the functional an.irle is suggestive of tuberculosis. The Costal Angle. ( iuilleminot' and Bouchard and (iuilleminot 5 have made an especial study ot this angle in its relation to pulmonary diseases. It is described as the angle between a line drawn from the center of the sternum to the upper border of a rib during inspiration, ami another similar line drawn during expiration. These two lines are traced by means of the orthodiaseope or in two radiographs. This angle varies direct!}' as the amplitude of the oscillat ion of t he diaphragm. It is very much diminished in pleurisy and in tuberculosis. The Cardiac Area. The cardiac area is reduced in persons with a tendency to consumption, and also in persons with pulmonary tubercu- losis. It i- larger than normal in cases which have recovered from i uberculi isis. G Topography of the Thoracic Organs in Radiographs. 'The Tube at the Level of the Sixth Dorsal Vertebra. 1. An.it ropnxh rior \ijrnph ii'ilh ///c l'l'i/i Itdi'i/il i l-'in. TOtii. The ,x/;/'m shows quite clearlv in the upp<>i' pail ot thorax and neck, the spaces between the bodies of the vert el >ra' being verv stn in.Li'K" marked. It sin >ws as a darker si ailow with parallel borders in the part of the picture where it is cov- ered bv the heart, but sometimes the separate bodies of the vertebra' may not show distinctly. The spinous processes of some of the vertebra- in this region may show as small rounded spots. The trui -h< ra ). i Cliuidf-, ( 'nnsrcss of TulTcu!(i-i-. P:iris, 1 S ' IX . - pit-rlfi-c. ( 'nnsin^s of Tiiht-n-uln-i-j. i':iri-. 1VK. :i ( lui 11, minor, ('. I!. * Sri.Min-. 141, 2S1, July lM, I'.Kl.l. 1 l.c Itailiiitn, Sept. 1."). 1 !)().'>. : -c. K. Arail. dcs Sciences, r-xxviii. 1 I-' 1 . June 1'J. l^H'.t. e< luillt-niinot, ('. 1!. ik- I'Afiul. ih-< S-i.-jH-t-<. ! K l , SfJ. Mnn-li 2."), ]W.~,. 1002 MKDICAL ELECTRICITY AND UONTCEN HAYS The bronchi and their branches, inside and outside of the lung, cannot ordinarily he seen in the radiograph. The clnricli* show distinctly, and so does their articulation with the manuhrium sterni. The xtcrniu/i is not usually distinctly visible in the dorsal radiograph, only its manubriuni can ordinarily be traced. The rihs show very well, and even those overshadowed by the heart can be traced in the plate. The lnn, from liieder 1 ) shows a shadow which is bounded as follows: Beginning close to the border of the spine the edge of the shadow of the superior vena cava passes down almost parallel with the border of the spine and merges into the shadow of the riidit auricle. The convexitv of the latter extends the width of the pinal shallow to the right, arid then curves in again to merge into the ri-ht ventricle at the intersection of the diaphragm and the spinal Then the cardiac outline is lost in the shadow of the spine. At the left of the spine the shadow of the ventricles is at first continu- ous with that of the diaphragm covering the liver and stomach, but l;tt( r diverges from it. The apex of the heart is free from any other shadow, and is about twice the width of the shadow of the spinal column from the left bonier of the latter. It is not ipiite at the lowest level of the cardiac shadow. From this point the border of the shadow pa-se< upward and inward, showing a slight concavity where the left .'utricle merges into the left auricle, and having a convexity over the onary artery, which is at a considerably higher level than the onvexity f)f the ri^ht auricle. There is <|uile a distinct angle be- tween the border of the pulmonary arterv. passing upward and inward, ' 1 ih.it of the aorta, which passes upward with a slight convexity out- ward. _', < ''i i'i/ 1: u'(i.--rnltir lnj>i}i/!'iij>lii/ in mi . 1 nit r im.
  • }i with //" /"' // /'/((/,/. The spine looks larger and less distinct, the clavicle snialliT and more distinct. The heart area is a little smaller and more 1 : l-'ort-ch, :i. -1. ('}>. ilcr HncntK'iist ., 100'J, vol. vi, p. ll.s. THK 0--HAY 1003 distinct. In this picture ( Fig. 707, from Kieder 1 ) the border of the vena cava begins at the junction of t lie shadows of the' right clavicle and the right border of t he spine, and forms a slight convexity as it passes down, but before it reaches the cardiac area it is covered bv t he spinal shadow. '1 he border of the right ventricle becomes visible at a lower level and forms a convexity which terminates at the junction of the diaphragm and the spine. It should not extend more than half the width of the spinal shadow beyond the right border of the latter. From the left border of the spine the shadow of the left ventricle; and the apex of the heart extend outward. It may appeal 1 in direct contact with the dia- phragm, but very often a strip of hin.tr is seen to intervene in this ventral position, especially if the .r-ray tube is at quite a hi.trh level behind the back. The left ventricle and the left auricle and the pulmonary artery form three distinct convexities, extending upward and inward to a point near the spinal shadow, where the border of the descending aorta is seen close 1 to the spinal shadow, and extending down from the clavicle to the heart area: it is only slightly convex. ( \\ emberg's Atlas der Radio.trraphie der Hrust ( )rgane. K. M. Kngel, Vienna. I'.tOl, gives an excellent guide to the topography in antero- posterior radiographs of the chest.) A convexity in the second left intercostal space extending outward from the median shadow in an anteroposterior radiograph is not usually due to an aneurysm. It is commonly due to the aorta being placed a little farther to t'lie left than usual. A diffuse swelling of the aorta is sometimes seen in old persons, ('specially in a radiograph taken with the tube behind and to the left. It indicates atheroma. not usually aneurysm. Radiography in Ot/nr Than the ^tii/itfnl I'lnnc. The first investiga- tions of the thoracic organs by means of .r-ray examination, made in a number of different directions, were by v. Criegu'-' and by Holxknecht . :; Kieder' has done more than anyone else to make the oblique and lateral methods of examination practicable. The tube is usually placed at the level of the sixth dorsal vertebra, and trenerally at a distance of not more than .~>0 or 00 centimeters from the plate. .'!. Topography of the Heart and (ircat 1 CNNC/S in Oblique Radiographs of fhi TJmrnx. These 1 pictures are made with the tube at the level of the sixth dorsal vertebra, and either in front or behind at an angle of 1") degrees from the median line, the plate being diametrically opposite. IF//// the TH/X- Htfiind mid l Kith* r Side.- The two oblique pictures with the tiilx 1 behind show the spine somewhat curved, its concave luirder smooth and formed by the border uneven and formed by th and confused by the angles of th large and somewhat vague. The clavicles show at a different an trie upon the two side's. \Vith the T nl>c in I'' rout unit to lather >^i. der KMfniL r ''n-t . vol. vi, p. 1 1 "v - Ycrhand. il. Knnirtvs,-. f. in. Mrdi/in. Karlsbad, ivi'.i. 3 Wicn. Klin. \Vnrli.. I'.KN). \o. in. and Di.- llnrntjronnlnciorho Diacnostik der Krkrankunirrn der Hrusti'niKr'wciih 1 Hanilmrir. Fuc:i~ (iratV and Sillcn. 1 '.)()!. ! Fort.h. d.-r Knt'iitircnst.. veil. vi. r.mj. p. M t. bv the bodies di' the vertebra 1 , while the convexity presents a notched border ilue to the different processes of the vertebra) ami to the angles 01' tin- ribs. The two scapula 4 present ([iiitea different appearance. The one on the >ame side as lite plate presents its customary appearance, while the other one is seen in profile, and seems like a rylindric bone not more than an im-h in diameter, extending downward from the shoulder-joint. (n} '/'A* ( 'iinlifn'dxculiir Shmloir \Ylnn the T/I/IC /x />\ I'/i iimii'ii jili i/ of l/ir ( 'firi/inrtixciildr .1/^.vx /'// n Itadinr/raph witli flic '] i/l l!i hi mi inn! in Hit' Iliijlil. There is the same clear space between the heart and the -pine, but somewhat narrower, and this is almost median line, as indicated bv the episternal notch. The shadow of the e-i ,; ihau'iis may be visible. c I 'o/io'irn /i/i i/ in Unit ii>tjr'/',)<). p. W2\ where the abdomen is so much more developed than the chest. Alterations of the Cardiovascular Area in Disease. An in- crease of infra-abdominal pressure shortens the shadow of the cardio- vascular bundle. Pleural effusions or adhesions variously displace or deform it. Cardioptosis (Kummo's disease) causes elongation and displacement dowmvard, with slight increase in width at the base and \\iih two separate pulsating areas at the left side instead of a continu- ous one. The appearance in this disease is very different, according to whether the patient is lying down or standing up. Enlargement 'or reduction in the si/e of the heart shows in the radiogra] >li. Pericardia! effusion shows as an increase in t probable diminution in the visible pulsation, diagnosis was reported by Janeway, 2 in which "> -I by lap] ting. :! out gen ray diagnosis of compression of the superior vena cava aortic dilatation was made bv Dopier in the case of a man with ;is, edema of the skin of the chest . but no cardiac murmurs. w Y. 1006 MEDICAL ELECTRICITY AND KONTCiEN KAYS Holzknecht 1 luis made numerous observations upon dead and living, normal and diseased persons, "which confirm the above statements. Amui'i/xni of the Aorta. This condition is evidenced by an un- natural extension of the normal shadow of the upper part of the cardio- vascular mass. The shadow pulsates and varies in position, according to the part of the aorta which is affected. Baetjer,- from a study of 101 cases, gives the following classification: (1) Aneurysni of the ascend- ing aorta gives a shadow which extends more to the right than to the left of the sternum. It lies above the heart, and is nearer the anterior than the posterior thoracic wall. ('-) Aneurysni of the arch of the aorta produces a shadow which extends a little further to the left of the Mernum and to various levels toward the neck. It lies nearer the anterior than the posterior wall of the thorax. (->) Aneurysni of the descending thoracic aorta casts a shadow to the left of the sternum and is in relation with the posterior wall of the thorax. The cases which have been referred to the author have often pre- sented the .r-ray appearance of an abnormal opaque mass in the upper median part of the chest, suggestive either of a mediastinal tumor, tubercular or malignant, or of an aneurysm. In one case the patient was a large young man of apparently splendid physique. The rational symptoms and physical signs were suggestive either of tuberculosis or aneurysm. and the radiograph was regarded as probably, but not cer- tainly, indicating aneurysm. The patient died a few weeks later from a Mii^le .-udden hemorrhage, which was regarded as positively arising from the rupture of an aneurysm. Many radiographs of tubercular cases show an area of opacity in the upper part of the chest continuous with ihe cardiac shadow and ex- tending to one side of the spinal shadow. OIK* patient had all the symp- toms of pulmonary tuberculosis except hemopt vsis and died a few months later of exhaustion. The condition of the rest of the lung will aid one in deciding whether such a shadow is cast by consolidated pulmonary tissue or bv an aneurvsm. Aneurism of tin Innoininntc .\r/(I ! '.'ill. Johns I lopkins I lo.-p., Jnn., I '.Kid. '.. . ^ ork \Iol. Jour., |-VI>. !>:',. I'.Ml?. p. 37!). 1 John- I lopkin- H<.~pi1;il Jiullet in. I'.i0<>. ! uici-i, Nov. :;, i '.MIII. TIIK .T-HAY 1007 rcct diagnosis of anenrysm. Radiographs taken at different times showed marked variations in si/.e which could not occur in a solid growth. Guilleminot 1 has even attempted to radiograph the aorta at differ- ent phases of the cardiac cycle. Transposition of the Heart. This condition, suspected from the physical signs, is verified by the radiograph. We may also be enabled to say whether it is a congenital malformation, as in a case of the author's, or due to displacement by pleurisy and the like. Estimation of the Size of the Heart. (1) This may be done by means of the orthodiagraph (Morit/), and a tracing made by the pencil while t he operator carries t he cent ral ray around the out line of the heart . ('2) Another method is by t he author's simple home-made apparatus, p. !> ( .S. ('.)) The orthodiagraph may be used to accomplish the same result of orthophotography (Lepper-Immclmaim) by having a small diaphragm in front of the .r-ray tube and carried with it. This diaphragm may be in the shape of a slit, adjustable so as to be perpendicular to the border of the heart at each part to which it is carried. - Tlu 1 author's simple method and Lepper-lmmelmann's method both accomplish the same result of making a photographic record of the cardiac area on a sensitized plate instead of a pencil tracing made by the operator, as in ordinary orthodiagraphy. The plate, in any case, should be in contact with the patient, and the latter should not move or turn during 1 he exposure. The I.epper-Immelmann method has the advantage over the author's that it enables the operator to guide the beam of .r-ray by direct ob- servation of a fluorescent screen placed behind the photographic plate, instead of guessing at the area that ought to be covered by the moving ray of liulit. The w.ay in which the photographic record of the boundary of the heart is produced is explained in the paragraph on the author's ortho- radiograph. (h Simple radiography or fluoroseopy may be employed to measure the .-i./c of the heart. Fluoroseopy, with the tube at a distance of 2 meters isO inches) from the screen which is placed directly in contact with the patient, gives an approximation to the actual si/e which is close enough for every practical purpose. The room should be dark- ened for a few muiutes before the examination is made. '1 he screen should be fastened in position and have a sheet of lead glass over it ' to protect the operator. Tracing-paper rovers the ii'lass, and the opera- tor traces the outline of the heart with a heavy graphite crayon (a packer's marking pencil). A radiograph would have to be made at a shorter distance and due allowance made for magnification. Teleradiographv, with the tube s() inches (j2 meter.-) away, is ren- dered practicable by the very powerful modern transformers. The transverse measurement of the normal shadow of the heart compared to that of chesl at same level is 10 to 'J 1 . Effect of Cardiac Movements Upon Rontgen Ray Measurements. iterfere wit h t his niet hod of v 17. 1 100S MKDICAL KLKCTKiriTY AND RO.VHiKN HAYS P<>xi!in/i ni' ///( Patient. \\here the greatest possible exactness i.s rei[tiired, as in making repeated examinations of the same patient, the recumbent position i- 1 >est . This position is re.-u'ul to the patient, who is compelled to hold still during the process of meii-uration. Other advantages noted by Morit/. 1 art 1 that the respiratory nioveinenis are more ample and the heart acts more regularly : the diaphragm occtipies a median position, not being di-placed by the traction of the weight of the liver or by the inte.-tine-: the abdominal wall is relaxed. The si/.e of the heart shadow is always smaller in the upright posi- tion, it also descends in front of the diaphragm, and is dragged down by traction of the diaphragm upon the pericardium. Sometimes the position is not important. Simple iluoroscopy, with the lube at a distance of M) inches, is only practicable with the pal icnt in an erect position. The tube may be in front of or behind the pat lent, with a slight pref- erence for the former position when the patient is erect as it gives a better view of the vertebra) and ribs and hence more exactly locates the heart. The tube should lie under the patient's back when the horizontal position is chosen for fluoroscopy. Rikr'* Mni.- -The patient lies face up on Morit/'s horizontal orthodiagraphic couch, the tube being underneath. A tracing of the outline of the heart and diaphragm is made upon a sheet of paper held in a horizontal position over the patient's chest; then, without changing the position of the patient or opacity at the lower part of the chest, and a larger or smaller area of un- natural t ranshicency between these two. In the case of an abscess of tiie lung, on the other hand, the opaque area is usually surrounded by an area of approximately normal translucency. l)'iu\ nntin! Diat/noxin of I'Uural Thickcnituj ami Ei'iuxion and Pul- tr.ntinri/ Abxa.ices fail to light up in the fiuoroscopic image on dee]) inspirat ion. ('.)} The diseased part of the lung casts a dark shadow. (-1) 'J'he heart is usually smaller and placed more vertically in the chest. (.")) Any alteration in the shape of the chest and position of the ribs may be better determined by the .r-ray than bv other methods. 1 he y/Y.s7 sign is, perhaps, due to pleuritic adhesions and is very fre- quently absent in recent cases. It is important if present, but its ab- sence does not exclude tuberculosis. The *, cnnd sign is of very great diagnost ic value. The affected apex may even become darker during deep inspiration. The third sign is of great value. The /wr//j sign is the subject of some doubt. Bouchard and lialt- ha/ar have found the heart smaller tlian normal in the first and second Mages of tuberculosis and believe that this acts as a predisposing cause. They find that the heart generally becomes enlarged in the third stage of pulmonary tuberculosis by a compensatory hypertrophy, due to the increased resistance in the pulmonary circulation. It is interesting to note in this connection that the heart has been reported to be larger than normal in cases of healed tuberculosis. The j'tftli sign is of value. Other FluoroHCOpic Signs of Earli/ Tuberculosis. The condition of the bronchia] glands ma}' be studied with the iluoroscope and is especially ca.-y to determine with a very small diaphragm. 77/r Caxtol A')ii the Apt\v <~>t tin Jjniij*. These have been made 1 the subject of study bv a great man}" observers. Adam, in connection with Albers Schonberg.' has made use of the com- pression diaphragm, examining 70 cases, and believes that this method gives better results than any oilier. (It requires a certain definite posi- tion to obtain the imatre of the apex of the him: free from the bone shadows.) Tt seems to he impossible to get the shadow of the apex of the hi n L: en t i rely free from the shadows of t lie bones, but a posit ion in which the plate is behind the neck with the tub) 1 in front in the median line an ima^e which is crossed by the shadow.- of the first and second i l-'ortseh. <1. Cel). Kurntircn., v..]. \. \V.. :;. Octoht-r, r.'Ofi. 1012 MEDICAL ELECTRICITY AND RONTC.EN RAYri ribs, but the opacity of the apex of the lung shows through the shadows of these ribs as well as through the intercostal space. The methoel is to have the patient lie on his buck upon a wedge-shape'd cushion, whose upper surface makes an angle 1 of about 124 decrees with the horizontal line. The upper extremity of the cushion terminates at the level of the shoulders and the head can be bent backward over it. The plate is placed behind the nape of the neck. A compression cylinder, with a K-i-cm. diaphragm, is so placed that the rays pass in an oblique direc- tion from in front upward and backward, covering an area extending from the lower part of the larynx to the junction of the manubrium and the body of the sternum. Sometimes the second, third, and part of the fourth intercostal space can be shown in such a picture. A moderately low degree of vacuum is used, and the Lumierc Sigma plates, are recommended, with an exposure of ten to fifteen seconds. The patient .-hould hold his breath during the exposure, which is preferably at the moment of deepest inspiration. The normal lung shows shadow lines upon the plate which are nearly at right angles with the shadows of the ribs, and which are 1 due to the bronchi and their accompanying blood-vessels. If these shadows are not clearly visible in a good picture it is an indication of trouble. Such plates are apt to be unsuccessful with patients who have short fat neck-, and also in cases of kyphosis or scoliosis. < >ne of their characteristic plates showed a cloudy shadowing of the whole second right intercostal space, with dark and bright spaces. The third and fourth intercostal spaces in the same case we're flecked with cloudy areas. The bony shadows of the ribs and clavicle 1 were altogether deeper than on the left side and somewhat spotted. On the left side there were circumscribed spots in the second intercostal .Mori 1 or less diffuse 1 areas of cloudiness were found in all cases where the physical examination gave evidence of distinct dullness. Cir- cumscribed spotting* were found in cases where the physical examina- tion revealed only catarrhal symptoms, but not in all of these. Another case showed decided spotting m the second and third intcr- costaJ spaces, though wit h very lit t le interference wit h the general t rans- mission of the .c-ray through both apices. This, combined with the physical signs, indicated a catarrhal in lilt rat ion on the left side, while 1 on the right side catarrhal rales were heard without any indication on the plate. Still a third characteristic plate showed two very dense and sharply defined shadows, about twice the si/e of a pinhead. The contrast be- tween the rmht and left second intercostal spaces was sharplv marked. In the third, fourth, and part of the fifth intercostal space 1 there 1 was a difference in the general brightness of the two sides, but here, where so much thickness of lung tissue has to be penetrated, the 1 judgment a~ to whether the appearance is pathologic or not is much more diflicult M at the apex. The' general effect upon the iluoroscopic se'reen was that the left apex was .-mailer and more dense 1 . . ;. plate showed a spotted cloudiness in the second left intercostal spaee. an evidence of some thickening, which, however, was not ex- ti'UMve i no'iuli TO make 1 a difference in the percussion note. The 1 two small .-harp .-hadous were supposed to indicate 1 calcification in a caseous focus. THE .r-KAY 1013 The fourth characteristic plate showed diffuse spotting of the second, third, and fourth intercostal spaces, which was also visible upon the shadows of t he clavicle and of t he t hi I'd ril>. The upper border of the clavicle did not seem sharp. This la.-t feature, of course, was only of value when the patient had held his breath during the exposure. "With the fl Horoscope the apex appeared cloud}', while thickening was visible in the lower part of the right lung. This plate showed that the infiltra- tion extended much lower than the percussion note would have indicated. It also shows that increase in pulmonary density is visible even through the ribs. The following conclusions are drawn from the 70 cases which Albers Schonborg and Adam examined in this way: An acute catarrh does not uive any Rontgonographic evidence, but thickening of the lung tissue can be discovered bv the ,r-ra\" before it is extensive enough to produce a change in the percussion note. ( 'onsei jiient ly. an .r-ray examination is desirable for cases in which the disease has progressed for some time in the form of chronic infiltrativc processes of both apices without catarrhal symptoms. 1 Shurly- states that the .r-ray demonstrates the fact that pulmonary tuberculosis ma}' progress to the formation of small cavities before ordinary skill in percussion and auscultation will detect it, and also that an .c-ray examination at the time of the earliest hemoptysis or fever will often show much more extensive lesions than are indicated by the physical signs. The author's own cases corroborate this state- ment . Bonney's book on pulmonary tuberculosis contains excellent radio- graphs illustrating different stages of tuberculosis. Pfahler's excellent radiographs of cases of pulmonary tuberculosis 3 illustrate the different conditions revealed by the ./'-ray in this disease. A patient of the author's had been perfectly well up to three months previously, when she had a severe cold. This was followed by another, and since that time 1 she had rapidly lost flesh and strength and had frequent hoinoptyses. A radiograph taken with the author's radiating cellular diaphragm showed the entire right upper lobe clearly outlined and denser than am," other part of either lung. Ji'iit met border-, and pi omit if ei'i'u.-K <}\ or empyema is shown by u dee] ). clearly defined shadow. Pneuniothorax shows a large area of unnatural transparency and a :: n 'a i >\ unnaturally < ij >ai (tie lung. Pyopneuniothorax is similar in radioirraphic appearance, but with the add it ion of a clearly defined area of dense i j>lcitrix>/ as a se<|uela to pneumonia is evidenced by restricted movement of the diaphragm, and pleurisy with effusion by a dark shadow. Broncho pneumonia may be easy or difficult to recognize, according to the sixe of the areas of consolidation. BRONCHIECTASIS This condition may sometimes be diagnosed on account of light areas in the radiograph of the lung. The best time to make the exposure is directly after a profuse expectoration. An interesting case in which this condition of bronchial dilatation was recognized by the .r-ray is reported by Pfeif'fer. 1 The .r-ray revealed also the presence of a drain- age-tube lost in the pleural cavity after an operation for empyema. Bronchiectasis may be mistaken for abscess of the lung, as the radiographic appearances are similar. FOREIGN BODIES IN THE LUNG Bullets are very easily located in any part of the chest. This may be done by means of two radiographs, one anteroposterior and the other lateral, or the localization may be made by the McKenzie-Davidson method. Among the interesting cases of other foreign bodies located in the lung is one of a knife blade broken off in the lung three months before the .r-ray examination was made. Meanwhile, symptoms similar to those of advanced consumption had set in. The knife blade was removed without much difficulty after resecting 1 inch of an over- lapping rib. The case was reported by Baldwin. 2 Another interesting case is reported by Russell. 3 The patient was a boy. twelve years old, who had swallowed a large black-headed pin five weeks previously, A week or two later there was cough with blood- stained sputum. Fluoroscopic examination showed the pin to be lyini: in the left lung with its point upward. The foreign body was removed through ;ui incision made into the lung. The case is exceptional, be- cause foreign bodies almost invariably enter the right bronchus instead of th'' left . as in this case, ]''rau;menis of a peanut shell, inhaled, did not show in one of the aut In >r - cases. THE LUNG REFLEX This is a symptom which has been de it i It i 1016 MKDICAL KLKCTHICITY AND KONTf.EN KAYS fnun a source of cutaneous irritation involving primarily certain spots, then, it' the irritation is severe enough, more remote pails may be in- volveil. It can l>e excited in lungs showing diminished resonance, the resonance being ahvays increased by nibbing the skin over the lung percussed. It is Used as a test of the resiliency of the pulmonary struc- ture. In the .r-ray examination normal lungs present a uniformly liii'ht area, which appears brighter during inspiration than expiration. The increased translucency due to reflex lung dilatation may be observed with the iiuoro-cope. It lasts for about two and a half minutes. It is used in the differential diagnosis of lung dulness due to consolidation or to atelectasis. If the dulness is due to at elect asis, as in some cases of bronchial pneumonia, cutaneous stimulation by vigorous friction or the use of cold water produces this increased translucency to the .r-ray by expansion of the air-vesicles. It does not take place in consolidation. RADIOSCOPY OF THE ESOPHAGUS This subject has been discussed on p. W\. RADIOGRAPHY OF THE 3PINE This will aid in the diagnosis of Pott's disease if the radiograph shows the presence of an abscess and erosion of the body of a vertebra. Thi> examination in the lumbar region presents the same difficulties and requires the same technic as for renal calculi. It is less difficult in the upper dorsal and cervical region. Vi;r all these parts of the spine tli<- patient lies supine on the plate, while ihe tube is over the median line in front at the appropriate level. The use of a compression cylinder for the lumbar vertebra' reduces the si/e of the picture, but increases its clearness. The lower dorsal region, where the spine lies behind the heart and liver, presents difficulties which ma}' be partly overcome by taking an oblique picture with the tube in front and to the right and the plate behind and to the left. The patient must hold his breath during the exposure, which, therefore, should not last much more than thirty seconds. Radiography of the Entire Length of the Spinal Column. This may be done, as in one of the author's cases, upon a glass plate - \ inches in length, or upon a celluloid film, for instance, the Lumiere Sm'iua film, the same sixe, or upon Hontgen paper, made by the Xeue Photografische < iesellschaft, Berlin-Sticglitz, whose agents in America are the Holograph Company of Xew York. This paper is about as rapid as an /-ray plate and is much more economic. Ihe pa; sent -hould lie flat upon his back upon the table, with the tube over the lower end of the sternum and the anticathode 2"> inches fi MI the plate. Five-inch spark equivalent. )5() ma., for fifteen seconds, or any other exposure of }.")(> ma. second- for a 1 "ill-pound man. The portion ot the -pine covered by the liver can be seen oiilv verv faintlv, |>o--ible to trace the ueneral line of curvature. ithors contact diaphragm make- it po-sible to secure good definition in a picture of thi- sixe. It cuts out the secondary rays ; i .. ' 01 n t he "Teat er part of i he .'--ray tube while permit : ing the direct ' I li rough a wide angle, and tin- causes increased deli nil ion and coi ,- it] t he radii 'uraph. -phial radiography does [ )( ,i conn.-! chieflv of iiisiif- he | ilat e. but in a lack < >f << int ra-t and detail. TIIK .r-KAY 1017 due to secondary rays original ing in the thick mass of tissue traversed.' This is remedied by the use of a diaphragm cutting off the secondary rays arising from the .r-ray tube, which increases the contrast and detail in spinal radiographs to a wonderful extent. Radiography in Scoliosis. An interesting observation lias been made by lioehm 1 in regard to 1 he etiology of this lateral curvature of tin; spine. Anatomic study .-how- that it is frequentlv associated with numeric asymmetries of the spine, so that a vertebra lias a certain char- acter on one side, while presenting on the other side the characteristics ot a vertebra either higher or lower in the spinal column. An example ot this is afforded in the case of a cervical rib and also in case of atvpic sacral \\mgs. These numeric anomalies occur at the cervicodorsal, dorsoluinbar. or lumbosacral junctions. Hoehm found them present in 17 out ot I'll cases examined with the .r-ray. Mspecial care is necessarv to detect these conditions, lie explains the fact that scoliosis does not appear until puberty on the ground that all the vertebra- are of practi- cally the same type until that time. Typhoid Spine. McRae- reports a case in which the .r-ray revealed definite changes in the vertebra-. I)unlop :! thinks that man}' cases of supposed typhoid spine are in reality cases of relaxation at the sacro- iliac articulation. The .r-ray may enable one to differentiate between these two conditions. The changes reported by McIJae in a patient suffering from typhoid spine were actual bony lesions of the spinal column itself. The .r-ray plate showed the presence of newly formed bone. He says that not all cases iif typhoid spine present such organic lesions, and some of them are poibly functional. 4 Spondylitis Deformans. This is a disease sometimes of tubercular origin, and sometimes accompanying syringomyelia or other conditions. The intervertebral cartilages become ossified, and this condition may be revealed by a radiograph. The remaining lesions perceptible by the .r-ray are the rigidity of the spine, in a position either of a straight "poker-back'' or of kyphosis, and possibly some of the bony deposits around all the articular parts of the vertebra 1 and ribs. Le Breton 3 reports cases in which the .r-ray was useful in making a differential diagnosis. In a case of my own the ankylosis was in the cervical spine and it \va> difficult to secure a favorable position ot the .r-rav tube and plate, Bullet Lodged in the Spinal Canal. An interesting case, in which a bullet passed through the spleen, stomach, vertebra 1 , and spinal cord. where it was located by the r-ray and removed, is reported by IVgram. 6 The pat lent recovered, THE ABDOMEN AND PELVIS A convenient method of lluoro-copy i.- to have the patient ,-tand wMi hi- back toward the tube and \\ith the fluoroscope in front. A medium degree of vacuum (resistance, '_' '. inches, radiometer, _\o. o ' A TIL r>rtlir.|>-il. A--I.C. Annual Mcctini:. Auir. -, I'.KHi; Jour. Am. M./.l. A.-.-oc... Pert. (1, I'.'in 1 .. p. soi . . il Mcrtinir. Ai. 1.. May lY,. I'.MII'.. p. l lot;. Ihi-1.. M.-m-h Hi, l)i)7. ' Mc.l. I'm-iTcss. Jan.. l'.i>7. 1018 MEDICAL ELECTRICITY AXD ROXTGEX RAYS Benoist) and a primary current of about 10 amperes' intensity No. 10 Tousey are employed, the anticathode being about 1") inches from the surface of the body. The size and mobility of the liver and spleen can be noted at a glance, and so can the presence of any large dense mass, like an appendicular abscess or hydronephrosis. Gene-rally speaking, however, pathologic conditions in this part of the body require a radio- graph and the fluoroscope may be dispensed with, or if used it had better be for a very short time. Oxygen inflation of the peritoneal cavity as for the knee-joint (page T074' has been used by <). Goetze, 1 Arthur Stein, and William N. Stewart 2 preliminary to .r-ray examination of the abdominal organs. Radiography of Biliary Calculi. Radiography is of value in the diagnosis of gall-stones, but this is one of the most difficult conditions in which it is used. The film, with an intensifying screen, should be lai 1 upon a table, and the patient may lie face down upon it. A film measuring about 14 x 17 inches should be used, and this is placed so that its -center is at the umbilicus. The tube is placed vertically above the center of the plate, the distance from the anticathode to the plate being 23 inches; 4-inch back-up and 30 ma. for thirteen seconds or any other 390 ma. seconds would be suitable 1 for a man weighing about 150 pounds. Two intensifying screens, two thicknesses of tin to obstruct secondary .r-rays arising in the tissues; o-inch back-up and 30 ma. for thirteen seconds is the author's improved technic. The difficulty is that some biliary calculi present very little resistance to the passage of the 1 .r-ray and show no contrast with the surrounding tissues. The stomach and intestines should be empty. By this method the anterior extremities of the ribs are shown more clearly than any other bony structures, but by the dorsal method the vertebra? and posterior extremities of the ribs ought also to show very well. The Eastman duplitized film is suitable. Gall-stones present a resistance to the passage of the .r-ray that is very slightly different from that of the abdominal tissues. A gall-stone, | inch in diameter, held in the closed hand, can be traced in a radio- graph, but with difficulty, not at all like a bullet or piece of glass. Nevertheless, a mass of gall-stones in the gall-bladder presents a shadow, though not so dense as a solid tumor or anv other solid mass would present, if surrounded to some extent by the translucent gaseous content- of the intestines. This shadow t Inns out at the edges where the ./-ray [Kisses through only a small thickness of calculus material and its out hues mav be verv vague indeed. The cent ral port ion of the shadow, due to the thicke-t portion of the mass, may be moderately dense, and Mill the Imht and shadows of this part of the abdomen may disguise it or normal shadow^ mav simulate this. A plate like this requires long development, and trifling inequalities in the sensitiveness of the film mav produce ;m apparent shadow where one does not really exist. Imperfections in the plate present the appearance of shadows or iften of increased transparency. Misinterpretation of the spots i- avoided bv using two plates, one under the other. A spot hows on both plates is presumably due to conditions in the it the patient, and a spot which shows on only one of the plates umably due to an imperfection in that particular plate. A rat her la rin- shadow, with vague out lines m t he gall-bladder region, Munch, Mirrl. \\orl,., Xovcmhir ]'_', Mils. M'"l. Sir. County of New York. < >ctnb<-r 'J7, MM'.). THK X-KAY 1010 may be stated to he compatible with the existence of a mass of gall- stones. It is always extremely difficult to say positively that gall- stones exist. Some eases, like one diagnosed 1>\- the author, p. KHil, present clinical symptoms suggest ive of gall-stones, but if the radio- graphic shadow is as dense at the periphery as at the center, and if the borders are sharply defined, it may be staled that it is not due to a mass of gall-stones. In the case referred to the mass was due to hvdro- nephrosis. The most that the radiographer ought to say is that the radiograph is or is not the kind of one that would be produced by gall-stones. In making the radiograph the plate may be placed upon the table and the patient lie upon it. either supine, with the plate over the middle of the abdomen at a considerable distance, at least 23 inches from the plate, or prone, with the tube over the back, at a distance of at least 23 inches from the plate. The xiii>picion in the-e cases. A radiograph upon a 11 17-inch plate takes in all of these regions, and it is po<>ible to get excellent detail upon it. Radiographs which -eeined to siio\v the presence oi' gall-stones sub- (jueiitlv removed by operation have I teen published by Heck. Tn'o f'a.sv.v Ejctnniiuil for Xu*i>(Ctnl {-lilittri/ Calculi. The radio- i'raphic tindiim- in these 2 cases are instructive. Kadi patient, brought outrla^. had a palpable -\vellin<>; in the region add'-r and had pain and othei ^yinploins su< r(r e T'l-n !;,,,! ,/,-;/-', M,,,!, of the First Case. I'd a V.'tLlMe a!i.: -I npadly. extending down - ' ' -id' - -[tine, which corresponded il a collection of u'all- Tiie-e have a d'-n-i de-ree , ,f opacity to the lli ' do 1'iot ? THK .r-HAV 1021 picture, taken \viih the stomach and intestines cut in-lv < mpty. .-hows that the}- were fecal in nature. "The second picture showed tlic same vaguely defined shadow below the liver region, obscuring the image of the ribs on that side, \vhile those on the other side arc quite plainly visible. "The conclusions to be drawn from these two pictures are, in the first place, that there is no renal, uretcral, or ve.-ical calculus present, and. in the second place, the picture exactly corresponds to that which would be found in a patient with a collection of gall-stones and without an}' "Teat amount of fluid in the gall-bladder. It cannot be stated positively that gall-stones are pre.-ent, but it seems probable." A collection of gall-stones were found v\ hen the operation va- performed. The Autttor'x Report on the Tim R- earbonate. or of barium sulphate (specially purified tor radiology), or of black oxid of iron, which is less satisfactory, or of zirconium o\id i "( 'out rast in." introduced by Kaestler .~ It requires two to tour time- the dost 1 of bismuth in the stomach. This can be introduced into the stomach and subsequently withdrawn through a tube, and i- quite harmless, even if swallowed in the ordinary way. The radiograph may be made with the patient lying either face down upon the plate or face up. or with the patient standing and the plate in front. Distance from atiticathode to plate 2o inches, back-up -park ~) inches, intensifying screen, :>0 ma. for four second-, or any other 120 ma. second exposure for a loO-pound man of average wai-t and hip measurement-. The exposure inu-t be irreatly varied according to -ex. weight, and measurements (see Kxposure Table, page S'.tS'. Fora very -tout patient the distance should lie increased. Kxposure should always be made as short a- po sible b the use of the be.-t inten-il'inu' screen. Thi- i- to pi-event 1(122 MKlUfAI. 1.1. Kt IHKHY AND KOXTUKN HAYS give a full expo-ure in a small fraction of a second. The different transformers ami the unfluctuating convener will do this in one- quarter -econd or. with anything like the maximum power, in a much ,-horter time. With the patient lying supine upon the plate the radiograph -hould -how all the vertebra-, their bodies, and transverse proce--e-. Foreign bodies in the alimentary canal, or in the bladder, or in the ti>sues of the abdomen are located by the same kind of a radiograph. The progre. of a mass of food and metallic emulsion through the alimentary canal can be studied in successive- radio- graph-, but owing to the cumulative effect of the .c-ray a limited number would lie desirable in the human subject. l'ancoa-t ha- -ecu poisonous effects from leaving large quantities of bismuth -ubnitrate in the stomach, and advises removing it with a stomach-tube as -oon a- possible if over an ounce has been swallowed. Made'- Mildest ed. in Is'.t't. tilling the stomach with "'as in order to -ecure a radiograph showing its si/.e. sha]>e. and position. He swallowed -ome Seidlit/ powder and had a radiograph made of his stomach, which wa- better than any pictures obtainable up to that time by administering opaque substances. ( 'ole and Finhonr revived this practice, but it has proved less useful than the other method. 1'fat'f and Nelsoir 1 have made GO fluoroscopic studies of the effect of laxative- upon peristalsis. In cats, after the ingest ion of food mixed with bi-muth. peristalsis could be readily watched. Dangers from the Ingestion of Bismuth Subnitrate and Desir- able Substances for It.- From 1 to 2 or even 4 ounces of bismuth .-ubnitrate max' be required, and if then- is a deficiency of hydrochloric arid a quantity of nitrites may be produced. Two or more deaths and -e\ eral cases of dangerous depression have occurred which are attributed to t hi- react ion. Bi-muth subcarbonate is thought to be perfectly safe in doses of 1 or 2 or even ~> ounce-, but bismuth oxychlorid is still better in the same doses, brcau-e it doe- not excite any reaction in the -tomach. Bismuth oxychlorid' doe- not relax the pylorus sooner than natural food and does ii"i cause constipation. It may be given well stirred up in a bowl of d and milk. The Bismuth Meal.- A convenient formula is a portion of mashed p"iato with '_' or more ounces of bismuth oxychlorid and a glass of .vat i-r. A n 'i her excellent one i- von ( iourevitsch's potato-flour decoc- bi-mutlr'. employed by the presenl author. An ounce of p"tato fl"ur. ' ounce of almond -yrup. G ounce- of milk, and I 1 , ounces uth o\ychlond are thoroughly mixed and poured into ( .) ounce-' 1023 are not so good as with bismuth. The metallic powder i- mixed with mashed potato. litirinni xiil/tlidtc and fermillac. a sour-milk preparation of aur<-eable taste and consistency, form the most generally satisfactory radingraphic meal. Gastric Findings with the Rontgen Ray. An increa-e in the vertical length oi the stomach is seen in cases of gustroptosis and cntcroptosis, and anything which cause- a loss of the fatty layer in the abdomen; thu> it nriv be seen after t he Weir M it chell t reatment ; and the stomach mav -how increased motility on change ot po-ture or pressure. Dilatation of the stomach occurs chieily in pyloric ob>t ruction by cancer or by adhesion following perforating ulcers ot ; he pylorus or duodenum Fig. Til 1 . The outline of the stomach with its bismuth meal 1 1 r_M MKDIi'AI. is clear and sharp in these cases even when the patient is recumbent. The cases in which dilatation i- atonic and not obstructive show in the recumbent portion an indi-iiiict outline. The shadow is that of a pool of dense liquid deep and opaque iii the middle, but shallow and increas- ingly transparent near the edges. ( luiii'its in l-'tin/i. One of these is the hour-gla-- contraction (Fig. 7 1'J .due sometime- to cicatrieial coniraction after ulcer, or to pcrigas- tritis with adhesions, or to carcinoma. It i.- sometime- spasmodic in cases of gastric ulcer. Circumscribed defects in the outline of the bis- muth shadow oi the stomach indicate pressure trom without or caused by the growth oi a tumor m the wall of the stomach. CliatujtK in Mnt/lili/.- IVri-tal-i- and changes of position, produced by normal pressure or by change of posture, may be studied with the ope or I iy me; m- of a -cries of ra.dioiiraph- eit her cinematographic 4 !i .nirer interval-. I he [engt h ot !/>//> thul {<><>< I in r< hi / m and lietween the shadow ol the bismuth meal and that ot the magcn-blase. It r- supposed to vary in width and quickness of formation with the amount of acidity. It would lie prominent in ulcer and ab.-ent in cancer. It i- prominent in catarrhal gastritis. (idxtrir ilctr tx-h'tric juice po--ibly containing pancreatic juice. This condition had been only temporarily relieved by an operation upon the gall-bladder. The patient would go to bed after having the stomach emptied liy a stomach-tube, and on aspiration the following morning, before taking any food or drink, the stomach would be found to contain a pint or more of gastric juice contain- ing neither visible or occult blood. The fluorosoope, after a bismuth meal, showed that the stomach was in a vertical position, large and flac- cid and with sluggish peristalsis. A radiograph made three and one-half hours later showed an irregular spot of bismuth adherent to the wall of the stomach near the cardiac orifice. The rest of the bismuth was in the last part of the small in test i ne and in the ascending colon. A diagno- sis of ulcer of the stomach was followed by appropriate treatment and cure. Difference in Appectrcince Between ( leer and Cancer of tin Stomach. The n/cli<' xi/tH/itoni ( "Xischensymptom" in (iermaii* is characteristic of perforating ulcer and may occur in any ulcer. It mean- that a radio- graph taken shortly alter a bismuth meal .-how- a certain spot oi great density where the bismuth extends into a cavity, and there i- often a lariie maiden-blase and a marked intermediate layer. If the ulcer i- at either curvature, the shadow may project beyond the uvneral outline. When there is a niche it usually protrudes from the lesser curvature, and it has been observed to become obliterated Hi the course ol ap- pn ipriate t reat ment .- ( 'an cei'. on t he other hand, cut - out a port ion oi the bismuth shadow of the stomach and is often failing in an intermediate layer. M. Hatldek' note- the following differential points between gastric ulcer and cancer: I leer is apt to cause pyloric spasin and retard empty- ing oi t he -tomach : the outline ot the stomach shadow is smooth; can- cel' at an early stage cause- gaping of t he pyloru-, and later may produce stenosis with greatly prolonged retention of the bi-muth meal in the stomach: cancer produces a jagged outline of the -hadow. I'titifiiltilitif nj If ejection ni (iiixtrn' ( urci itoHin Indicated )>>i tic l-{- h. The more favoral)le cases are those in which the fish-hook out- line ol the lesser curvature and pvlorus are retained. Radiography in Intestinal Obstruction.- . I u-t as in the : Schlcsinfior, V.\i\<* Aciditatsbcstirntniiiiy dc- M.Mirciimhalt vi-rt'.-dirrns. N'rrcin-liiTichi , Mcd. Kiinik. I'.Ml. S. ( .i.">u. Walter \\ . Ihiinliur-icr, Amcr. Jour. Mcd. Sri., vol. civ. tUK n. '-'01. \\cin. klin. Woch.. .January 11. I'.Ml', \\v. 12. p. f.7. ll)2t) MEDICAL EI.Ki TKiriTY AND KOXTCEN HAYS stricture of the esophagus a bolu- of metallic emul-ion will show in a radiograph of the abdomen, and its position a certain number of hours or days after its intre-tion will indicate the site of an intestinal obstruction. In a case reported by Kinhorn 1 130 gr. of bismuth sub- nitrate in a pint of milk were swallowed. The radiograph, taken twenty-four hour- later, -howed a dense mass filling a part of the in- te.-tines. then a contracted portion where there wa> no bismuth, and a portion beyond that wa- filled with it. The location was thought to be in the lartre inte-tine, and to test this matter another radiograph wa- made five day- later, after the original amount of bismuth had all been pa>-ed. Before making the radiograph '.->() gr. of bismuth in odd cc. of water had been injected into the rectum. The same radio- graphic appearances were found and. as it was extremely unlikely that the injection had pa-.-ed beyond the ileocecal valve, it was regarded as quite po-itive that the -tricture was in the large inte.-tine. Radiography of Intestinal Adhesions.- A case < Fig. 711) examined by the author for I )r. Robert ( '. Kemp suffered greatly from constipa- tion, attributed to adhesions following one or two operations upon the pelvic organ.-. The symptom- pointed to the >ignmid flexure or the rectum as the seat of obstruction: but the picture, after a bismuth enema, -howed that while theentire large intestine was in normal position and permeable to the injection an almost empty region remained in the tran-ver-e colon. The injection distended the parts on both sides. It -eemed a- if tlii.- condition could only be accounted for by pressure either from a tumor, which could be excluded, or from a band of adhesions. 1 he latter wa- found at operation. '1 he n cun/fii nt jx>.^it inn . the patient lying upon his back with the plate underneath. i> often used by the author, because displacement of the -tomach and inte-tine which are not corrected by this position are u-ually rendered permanent by adhesions. The Duodenum.- Radiographs, as a rule, do not show this part of the inte-tine at all. or only a> a -hadowy outline, making a curve around the pylorus with its concavity toward the left. Kinhorn's method of blocking 1 he duodenum by inflating a rubber ball, passed into the duo- denum by an esophageal boutiie. gives an excellent picture of the duode- num when succes.-fully accomplished, and. of course, the rare cases of -t( no-i- of the duodenum from cancer or ulcer also cause it to show in the radiograph. 'I he bulbils duoden or cap may show as a dense shadow, -eparated from that of the -tomach by the clear space of the pylorus wit h< iiit indicai iim any le-ioii. In Mime ot the author- ca-e- a -mall dense -hadow has been seen ai one part ot the duodenum -ix hour- alter the ingest ion of a bismuth meal, and thi-. combined with the symptomatology, has been taken as indicating duodenal ulcer: and tin- diagnosis has been confirmed in ' ' ca-e- which have been operated on. Six hour- after a meal t he bis- - commonly to be -een far down in the pelvis or low down on the 1 ither m the la-1 part i it the small inle-tme or in the cecum -cendiim colon. 'I hi- tact make- any -eparalc -hadow at that time to the median line, and near the second or third lumbar vertebra 1 , c.' >U- ot i him lejial ulcer. rity of ca-e- no particular information in regard to the ;- obtained in t he r-ray dia trim-is; but . of course, anv b-iruction from any cau-e would be -hown bv the arrest ' N V MI -I .Inurn., Mav 1--. ion; THE .r-KAY 1027 of the bismuth meal ;it tliat point. Lane's kink may be revealed in this way. The appendix is sometimes to be seen in radiographs made after a bismuth meal, or after an injection of bismuth or barium. The fact that it is visible does not indicate any lesion. The colon is usually best studied from a radiograph made after a rectal injection of about 2 pints of a liquid holding in suspension barium sulphate or bismuth oxychlorid. Barium sulphate . . Bolus alba Water. . Such an injection fills every part of the large intestine from the anus to the ileocecal valve, and some of the author's radiographs show that even this is sometimes passed. Normally, the colon forms a sort of letter H, with the splenic flexure reaching far up under the ribs; the hepatic flexure, extending not quite so high, but still well above the level of the umbilicus; the transverse colon at about the level of the umbilicus (somewhat higher when recum- bent than when standing); and the sigmoid flexure, extending from well down in the left side of the pelvis, up out of the pelvis, and then down again into the rectum. ClHintjt'x in Position of Colon. In cases of enteroptosis the shadow of the transverse colon may fall far down in the pelvis, but on operation in the recumbent position this may he found to have been somewhat exaggerated in the picture 1 . Cases of old adhesions, like Fig. 712, a patient of Dr. Kemp's who had been operated upon for appendicitis and pericolitic adhesions, sometimes show the hepatic flexure much below its normal level and the whole ascending colon and cecum fallen together, instead of extending up along the right side of the abdomen. \ortntil J'IIWKJC of Food Through tin 1 Colon. There is a to-and-fro peristalsis, which favors the absorption of the nutrition from the colonic contents and a slow general progress toward the rectum, with occa.-ional forward mot ion of a mass occupying a large part of the length of the colon. Hol/knecht first observed this, and found that it takes place only once in about eight hours. Obstruction of the colon would show by arrest of the bismuth meal and also of the rectal injection. A case of the author's, also a patient of Dr. Kemp, has very marked constipation following operations upon the appendix and ovaries and uterus. A bismuth injection was given, but no meal. The radiograph in the recumbent position showed the normal out- line of the colon, but at the place where the transverse colon crossed the spine there was a clear area o inches in length. This was evidently a portion of the colon through which the liquid injection could readily pass, but which was kept flattened out instead of becoming distended. The picture was so good as to make this quite positive 1 , and its appear- ance suggested pressure upon the colon where it crossed the prominent vertebra 1 . This sometimes produces a similar aspect and must be guarded against. In this case it was excluded by the fact that the place in question was at the upper part of the abdomen and the line of demarcation was very sharp. Another possibility was pressure from a tumor, but there were no signs O f this in the radiograph or upon palpa- 102S MKD1CAL KI.KCTmriTY AND KoNTr.KN HAYS lion. The probability. \ herefore. \v:is that it was due to pressure by a band of adhesion-. Fpon operation by Dr. Parker Syins there was found a band of adhesions :> inehes broad ;ind encircling two-thirds of the cirruint'erence of t lie gut . Chninji N in tin N.'':< ami Motiliti/ of Different I\iri* of UK Colon. Moii'acolon. or me^acecum. .-how. by an enormously large shadow, and in cases where the lirst injection ot a couj)le of pint- surest s this coii- dition. a much larger injection will reveal the extent of the dilatation. In a recent case the cecum and lower part of the ascending colon were very laru'e. while the caliber of the descendinu colon was very small. No coii-t ipat ion wa- present a.- a result of thi- condition. ('///// tnohili , or unnatural mobility of the cecum. will be shown by it- change of position on pres-ure. It has been thought to have a cau-ative ettect in -ome case> ot appendicitis. Chmnic co/ome part of the colon, and sometimes the condition revealed by the ./'-ray is one requiring operation. It may be sh"\vn to be due to simple muscular weakness in the wall of the colon evidenced by lonsj; retention in the colon, or it may be shown to bo duo to adhesions of the rectum or sigmoid producing mechanical obstruction. If the .r-ray shows the bi-muth meal long retained in the rectum this would indicate lessened sensibility and reflex action there, or spasmodic cont r.ict ion of t he sphincter ani. The rectum and -igmoid flexure are best seen after an injection which I- m. 71 I 1 does not extend beyond these parts. The Skiagraphic Enema. For a rectal injection a decoction of potato Hour. 1 ounce to 2 pints of water, i> prepared by mixing the potato flour at fir-t with a small amount of cold water and then pouring it into boiling water. Three or 4 ounce- of barium sulphate are thor- oughly mixed with this liquid ( von ( lourevitsch). The decoction must be perfectly liquid or it will no! flow properly through the tube. This pui.-ito mixture iiives excellent picture-, and the author prefers it to the following formula, which has only the advantage of requiring no cooking barium sulphate, '.'> ounce-; bolus alba purified powdered kaolin). ', pound, and water up to '2 pints. Many of the author's radiographs have been made with thi- mixture and never with any bad effect, but i' i- ciincei\ able that some of it minht be retained and become 1 dry and hard. Foreign Bodies in the Stomach and Intestines. These 1 are readily located if metallic, of as larize sixe as a coin, and if the person is not too Ian:' 1 . A needle might e-cape detection. The .r-ray ha- been used to locate stolen property swallowed by criminal-. '1 hi- i- -aid to have been done at the diamond mines and ai-u in the mint in Japan, and a stolen rmi: ha- been located in this \\ay in the pri-on at I )a\ enport . Iowa. Radiographic Studies of the Passage of Different Food-stuffs from the Stomach and Through the Small Intestine. Observations been made by \\ . I', ('aniioii' upon a cat, to which '2-~i cc. of fats, ' irbohvdrate-, <>r of albumin wa- given, mixed with bismuth sub- /<;/.- were ,-een to remain in the -tomach for a long time, uradiial v pa nm into the small intestine as the previous portions of I '-orbed or passed into the la me intestine. There was no accumulation nf fat in the small intestine. A/hunii/ioitlx were seen not : Am. .lour, of I'hy.-inlotrv, U, IJss, I'.tOl. TIIK .r-KAY to leave the stomach during the first half hour, except white of egg, which almost immediately passes into the small intestine. The maxi- mum amount of albuminoid* is found in the small intestine at the end of two hours. ( '(ir/>olii///i-n/i x pass direct ly into t he duodenum. A mixture of fnts. iillm /in nnnls, and I'ltrhufn/flffitcn has an intermediate t hue fit re- tention in the stomach. The presence of the fats slows the progress of the other two. DoiihliHi/ the amount when carbohvdrates are niven alone increases the rapidity ot passage, hut doubling the amount of an albuminoid meal retards it. 'I'he moment at which the different food- stuffs administered singly appear in the large intestine is about four hours for carbohydrates, live hours for fats, and six hour.- for albu- minoids. Radiographic Characteristics of the Stomach in the Infant. Leven and Barrel 1 find that the infant stomach lies in a hori/ontal position, with a portion ot its greater curvature lowermost. It seems always in a condition similar to that known as dilatation, not adapting itself at all times to the volume of its contents as in the adult. After the iugestion of sO to 17") cc. of milk the infant stomach empties itself in from one and three-quarters to two hours. Other radioscopic studies of the infant stomach* show that it con- tract- throughout ITS entire extent, not merely around the pylorus, as in the adult. This contraction is a reflex from the gastric muco-a. and if the latter is hypersensitive, vomiting occurs. Obstinate vomit- ing of infancy is not a condition of stenosis or spasm at the pylorus. Km one of hypersensil iveness, and this may be promptly relieved by the administration of sodium citrate. Radiography Applied to the Desmoid Test of Stomach Func- tion. The digestion of connective tissue may be ,-tudied by having the patient swallow" a capsule made ,,f thin pi Id-beater's skin and contain- ing -'2 nr. of powdered black iron oxid. This is to be taken at the end of an ' n'i linary meal. A radiograph made seven hours later will show whether the ^old- beater's skin has been digested. This, according to some observers, i- the average time required; if not, the capsule of iron still shows a i li.-t inct dark spot. (J. \Y. Schwartz 3 found that connective tissue was completely di- gested in two hours in a case of very marked hyperacidity of the gastric jUire. I>. Horwit/ 4 has emploved Schwartz's method in 1 1 cases. He gives a little bag of bismuth after a regular test breakfast, and has the patient lie on his left side to retain the capsule in his stomach as lonn as possible, and the patient should take nothing but lea and water during the entire day. A little piece of thin rubber tissue tied around the bismuth with 00 catgut may be used instead of the ban of ^old- beater'- skin. The catnut is digested in the same length ot time as nold-beater's skin. lie says that if radioscopy show.- the bi-muth ;i- ;i -mall opaque >pnt in the stomach or intestines more than three hour- after swallowing it, tin- indicates a lack oi acid in the gastric secretion. When the connective tissue of the ban i- < line.- ted the 1030 MKDICAL F.I.K( 1HK II V AM) RONTGEN RAYS bismuth escapes and is seen as a larger and valuer area of cloudiness, and if this takes place in an hour and a half or less, extreme hyper- acidity is present. Freeing of the bismuth in two hours indicates moder- ate hyperacidity: in two and a half hours, normal stomach digestion; in three and a half hours, slight hypo-acidity; in four to four and a half hours, extreme hypo-acidity; and in five hours, anacidily. The. last- named condition was always found in cases of cancer examined in this way. Thi- is a modification of Sahli's desmoid test, based upon the fact that the raw connective tissue of the bag is not digested by the pan- creatic or intestinal secretions, but only by the gastric juice, and only when the latter contains pepsin and free hydrochloric acid. Schwartx's radiolo^ic observations show that no ingesta of any kind are ever retained for more than ten hours in a stomach of ap- proximatelv normal si/.e and without stenosis. Hot'fnian's conclusions from the radiographic examination of 100 patient- with diseases of ilie stomach are that the .r-ray is only oc- ca-iotiallv of assistance in diagnosis. If the stomach is dilated bv gas and a bougie is introduced, the latter should norinallv follow a certain definite curve, but in gastrop- tosis the bougie is seen in the radiograph to pass almost straight down to an unnaturally low level. 1 An hour-glass stomach was diagnosed by Holzknecht and Brauner. 2 The radiograph was made with the patient lying upon his back upon the plate with the tube over the abdomen. He had swallowed a sort of paste made of rice and milk and powdered bismuth subnitrate. Two dark shadows could be seen separated by a clear area representing the place of constriction. Fig. 7b> by the author shows an hour-glass stomach resulting from old adhesions. The patient was referred by Dr. Kemp. An example of the value of the .r-ray in the diagnosis of intestinal diseases may be mentioned -a case described by \\ iesner.' 1 An opera- tion for appendicitis was followed by attacks of acute colitis occurring every two or three weeks. Radiologic examination revealed the fact that the ceciim and a part of the descending colon were bound down by adhe-ions. and that a small blind pouch had been formed in this part of the inte>tines. This was relieved by an operation and another radio- graph three months later showed the colon in normal position. The colon i- to be injected with a metallic mixture before making such a radiograph. Technic for Radiologic Examinations of Stomach and Intestines. Hul-t 1 ha- elaborated a technic for the radiologic examination of the stomach and intestines which is an abridgment of Holzknecht.V and i- ba-ed aUo upon Hieder's" work. The patient, whose stomach known to be empty, -tands in front of the .r-ray tube, which is en- an opaque u . hi-,- ., ;,,! 'riicrap I Uui'iit LTi'H., Vi il \ ill, \'i. '.',. THK X-RAY KKU the normal ray, or a regular orthodiagraph may he used. The patient swallows a Seidlitx powder in two parts, the soda first and then the acid, each dissolved in half a glass of water. The posit ion of the right and left domes of the diaphragm are noted hy fluoroscopy, penetration No. "> or (1 Walter. Now, as the stomach fills with gas it looks trans- parent, like the lungs. This light area may he traced through a series of radiographs and is called the M/i.""> gr. of bismuth subnitrate. It' tlie patient is turned l."> decrees to either side the opaque mass may be watched as it passes down' through the esophagus. A swallow of water may he required to assist this. Looking at the patient from directly in front tluO/m/is. \ : M ph made -i\ hours after the inire-tion of the bismuth will show whether il has passed out of the stomach, and will thus test the motor efficiency of the organ. Later radiographs will trace the bismuth through the intestines. Use of the Duodenal Tube in Radiography. An elongated -tomach- tube. with a perforated metal ball at the end, is passed into the ,-tomach after swallowing a glass of milk and water. 'The patient lie- on hi.- right side and after a time the tube pa.--es into the duodenum. Then a rub- ber ball surrounding: the metal end of the stomach-tube may be inflated and will arrest the passage of a -mall bismuth meal through the duode- num in such a manner as to secure an accurate radiograph of t his port ion of the intestine. The duodenal ball is deflated and the apparatus is drawn out through the mouth, dross and Kinhorn and Cole and Skinner were 1 the pioneers in this method. Intensifying Screens in Gastro-intestinal Radiography. There is no need for great detail in these picture-, and there is every rea.-on n .- Fin. 71 for desiring to make short exposure:-. A transformer current ot '.() kilovolts and about .")() ma. will make these with an exposure ot le-s than one-quarter second if a good intensifying screen i- used. The Author is Opposed to Cinematography of the Stomach.- Such a rapid -cries of pictures can only be made upon a iilm. and film- require a longer exposure than the fastest plate-. Modern .r-ray apparatu- are so powerful that with the most rapid plate and the best intensifying -creen a u'ood picture may be made with an exposure ot one-twentieth to oii"-tifth second, or with a film and an intensifying -creen one-tilth to one second. Hut to do thi- the same amount of .r-radiation traverses the body as if a 12-inch induction-coil were u-ed with the same nd an exposure ot 1034 MKDICAL KLKCTKICITY AND H()NT(iF.N RAYS tir forty exposures of one-fifth second each with the strongest current radiance does not seem as risky as twenty or forty exposures with the radiance formerly employed. Imt such is the case. All the necessary information may he safely gained with a comparatively small number of the most sensitive plates reinforced by the best intensifying screen. ( '<>!( 'N (irnuKjcnicnt for nultocincHiutoyraphy comprises a lead box like a camera, in which the film extends from one roller to the other under an intensifying screen, against which the film is pressed at the moment that the current is turned on. The current is broken automatically after a certain fraction of a second, the pressure upon the film against the inten- sifying sen-en is released, and another portion of the film unwound. The I i_ r . Tl'i Kadioirranh of stomach. Deformity of duodenal cap indicative of ad- niall diaphragm was used, tin 1 stomach having been .:.. , iti-d liv pn-\ ions radiographs picture-, of ciiurse, ;ire the full si/e of the -tomach, and reduced copies ai'e made upon ;i -trip of cinematograph film. It is nut practicable to make cinematograph pictures directly with a camera pointed toward the fluoroscopic screen as if that wen- a mov- ing object. The expo-ure would have to be so ion" 1 as to give a blurred iinai!'- i>t any moving object . The author is strongly opposed to the use of the fluoroscope either fur examination or tor the purpose of determining the most favorable p'i-i'i vertical with the patient -tandinu before it, or it THE X-HAY lOH") may ho horizontal under the table upon which the patient lies. Safe as it may ho made iur the operator, an element of danger remains for the patient, in the fact that while the .r-radiance may he reduced to a weaker strength than used in radiography, any fluoroscopv takes a tre- mendously longer time, and could only he made relatively safe hy deter- mining beforehand the danger limit and using a time-switch to turn off the current long before that had been reached. Not alone the po.-sibilitv of dermatitis, but of disturbance of blood, metabolism, and excretion must be taken into account in determining the safe time of exposure. Accidents with the fluoroscope wore frequent in the early days when used in the search for foreign bodies in the hand or for the examination of the knee and other joints. The extension of its use to the stomach, where a much stronger radiation is required, is additionally dangerous. THE AUTHOR'S TECHNIC FOR GASTRO-INTESTINAL RADIOGRAPHY Preparation.- -For forty-eight hours before no .-olid food or any- thing containing milk; plenty of nourishment can be taken in the form of clear soups and broths, or clear jellies, coffee or tea wit h sugar, but with- out milk or cream; these can be taken every t h roe hours. A laxat ive t wo nights before and a laxative the night before the examination. A prescription is given for tinct. belladonna, dose 10 drops, to be taken three times a day before meals; and the last do.-o to he taken the morning of the examination first thing when getting up: then fifteen min- utes later to bo followed by-?, teaspoonful sodium bicarbonate in water. Composition of the Barium Meal. This consists of 5 ounces of barium sulphate thoroughly mixed with fermillac (two .'-pint bottles : this amount fills two cups. Postures for Gastro-intestinal Radiography. 1. Standing with the tube behind, anticathode 2o inches from the plate, and the plate at an adjustable height in front; umbilicus usually at middle of plate. We must not allow the patient to assume the "straight-front" posture, as in Fig. 717, with the hips so prominent behind as to make 12 or l-"i inches of flesh to be penetrated by the .r-ray at right angles to the plate. This position makes it impossible to get a good picture of the lower half of the abdomen in a stout person and even in a shapely person. as in Fig. 71S it is easy to see how much more uniform the ettect on dif- ferent parts of the plate will be with the patient standing with the puhes pressed against the plate and the hips down. This first position is seldom used by the author, because it is less convenient and less certain to yield a good picture in any but a slender person and one who can be depended upon to stand absolutely still. It i- used occasionally for the first picture after taking the meal, to show the very lowest level to which the stomach extends in a case of severe gastroptosis, and to show the exact level of the liquid content- of the -toinach and the clear laver above the opaque meal. The author's graduated filter tor equali/ing the exposure (page 1011 will frequently be required tor a i 1 x 17 inch plate in this posture. '_'. Standing in an inclined position with the abdomen resting au'ainst the plate and the feet upon an adju-table rest. The hips as- sume a desirable position naturally V\^. 721 . There i- a mark upon the tube-stand indicating the height for the tube and the aniilc at which it should be inclined. These adjustments are made fir-t . 1 he patient most 1030 MKDUAL ELECTRICITY AND KONTCKN KAYS oases. The tube is placed in the median line behind, at such a place that the anticathode is '23 inches from the middle of the plate. This picture -hows the level to which the stomach extends and the shape and whether the duodenal ca fill-. turf i- made in this po-ition about fiftee the plate under the abdomen and the tube over. ; from middle <>f the plate, which i MEDICAL ELECTRICITY AND RONTGEN RAYS I i^. 721. Semi-erect posture for gastro-intestinal radiography I ^MBI \ ;'!.'T'- >ii i' 1 ' n :K]V to rceeive the pl:itc in its eussette fur Castro-intestinal ruli' 'i r r;i| ili.v, M'lni-erect . THE X-HAY 5. Author's device for gastro-intostimd radiograph v, semi-orort. AdjuM foot-rest. Frame holds plate at proper height. rip. 724. -Author s frame for holding plate in an inclined [lositinn fur gastro-intestinftl vals, beinnninti' three-quarters of ;m hour after finishinji the 1'ariuin meal and with everv effort to secure dear definition ot the stomach and duodenum as free as possible from respiratory or peri-taltir movements, ('are must be taken to prevent compression ot the pars pylorica between the abdominal wall and prominent lumbar vertebra 1 . As a routine mea-ure have a cushion about '2 indies thick under the pelvis and another under the chest. The abdomen should re.-t liuhtlv on the MKim AI. KI.KI TKICITY AND KONTCKN KAYS ioKrapm "t the mte-ime: proi \~> degrees lower than the pelvis. RnuiOL'r.'ipliy of tlii' ;ippenilix, prone, with :i Pornprcssioi L' under the ri^ht 1041 plate without marked compression. The hack -hould he .-Iraiiihl ( Fiii'. 7'2 1 ). The chest and face should he right perfectly free iii ToilM'v's position. drill 1 view of the ;ip].rndix. The appendix plate is S x 10 indies. All the dt hers are I I x 17 indies. .">. Six hour- after the meal a picture is made in the same posture as N<>. L'. to -how whether the >tomadi is empty, what parts of the intes- tine are occupied by the meal, and whether there are malpositions or deformit ic- ( if any part s. hmir< after the meal and immediately after an enema con- ; i>tiim iii ID ounce- of barium .-ulphate and 1 ! pints of warm water a picture i- maile iii the -ame posture as Xo. 2. Thi< i~. Ap- 11)41 )ermeability and dilatability and position of all part- of the larjio t inc. . Six hours after the meal and immediately after the enema a irraph is made in the author's position (Fiji. 72.1'. The patient iroiic upon the plate inclined so that the pelvis is 45 decrees higher the chest. The elbows and shoulders rest on cushions raised the floor and the limbs extend alonji the top of the table. This ire -hows especially whether different part> of the transverse i are free to jiravitate toward the thorax. Number (1. for instance, have shown ptosis of the transverse colon way down into the pel- ind Xo. 7 will show whether it is bound there bv adhesions and Hadiotrriiphy of the -toniach and duodenum, prone, with thoraeir and i- to prevent coiniin---ion of the stomach anain.-t t he hodies of the verte- c'liild only be benefited by an operation. If it jiravitates freely toward thorax in the author'- position a belt and pad miu'ht relieve the -.in' >' ifn-. The Author's Graduated Screen for Equalizing x-Ray Exposures. an invention of the author's, consisting of a -licet of aluminum inch thick ; ,||,1 |i ;i \-inii one or both edu-c- beveled for about ?, to coini- 'o a thin eiltie. It i- fastened to the tube-f the peh'i- and the lower < 1< ir-al reu:i< m. \< I. The umbilicus is usually about at the level of the crest of the ilium and i- to be at the middle of the plate. Hut in a tall per- son the umbiliru-: i- u-uallv far above the cre-t of the ilium and the stomach is apt to be at a very high level. In -udi a per-on the umbilicii- i- a much better li'uide for the proper position of the plate than the crest 1046 MEDICAL ELECTRICITY AND ROXTGEN RAYS of the ilium, and very often the middle of the plate will have to be an inch or two above the umbilicus to include the entire stomach showing upon a 14 x 17 inch plate. In a person, on the other hand, whose um- bilicus is below the crest of the ilium the latter should be at the middle of the plate. \<>fr 2. Each intestinal picture ought, if possible, to show the en- tin 1 intestinal tract. The standing plates ought to be low enough to include the anus. This will ordinarily be the case with the um- bilicus at the middle of the plate, but with a tall or, rather, a long bodied person we must be sure that the perineum is above the lower edge of the plate. In this long bodied person the standing plates may very well not show the uppermost parts of the intestine, such as the splenic flexure, and we must make sure of including this in the final picture, in Tousey's position, though it be at the expense of not including the lower part of the rectum. \d(i o. (iaU-stotic Pictures. The gastro-intestinal pictures are precrded by one before the barium meal to determine the presence or c oi Lrall Atones or other calculi. The patient lies prone upon the plate without any precautions to prevent compre-sion of the abdomen. Hi' 1 uml>ilicu- is at the middle of the plate and the anticathode directly ;ibove that at a distance of '2'-> inche-. The -park equivalent should be - \vit hoiit or 5 inches wit h 2 t hickne<-e- of tin to arrest secondarv I:LI' in the tissues. The author'- ura dilated filter open above lull reducing the inten.-ity of radiation at the waist, should For a lady with a -mall waist and larue hip- and chest. The In-low and with aluminum above is used for a woman with J-nia and wai-l and lariie hip-. No liner i- u-ed for men or for larire waists. In Kiii. ~'.\'.\ gall-stones -howed even after the m Flie expo-tin- and development should be -uch that everv detail THE X-RAY 1047 present will show when the plate is held up before daylight at the win- dow. No part is to be too dense for that, and no part is to be so thin as to require special tnmsillumination to show details. The plate which a professional photographer would select to make a print from is best. If it shows clearly, the spine from in front and the lowest. ribs, it will be very apt to show a "'all-stone if present. The fact that the picture does not show a gall-stone does not prove its absence; but the author has come to believe that the above technic will enable one to say that it is unlikely that a "'all-stone is there. \ot<- 4- r '" n(> duration of the exposure should theoretically be one- fifth second or less, so that the peristalsis could not possibly show. With such an exposure the stomach would be just as sure to be motionles.- in the picture as the minute-hand of a clock in such a snapshot. A gastric exposure lasting several seconds may show movement similar to that of the minute-hand of a clock in an exposure of a minute or more. Hut in the author's experience an exposure of one to three second- for the prone pictures of the stomach gives all the necessary freedom from motion with a much easier technic than much shorter exposures. The equivalent spark should be ."> inches or more and the exposure and de- velopment should be such that the plate shows excellently when held before a window; the spine quite transparent but with good detail and the stomach very transparent, while the abdomen at either side is very dense. The plate should make an excellent print, showing the stomach black upon a generally white background and uive a good print of the symphysis and ranii of the pubes and of the hip-joint-. A stomach plate whi.-h requires special transillumination should not sati.-fy one. Some latitude in the matter of exposure can be compensated for in development, but great overexposure with accompanying undcr- developmeilt or the reverse can neves 1 produce the best results. The best way is to have a certain technic and vary -imply the time accord- ingly to the sex, weight . height . and waist and hip measurement-. < )ne -hoiild record all these factors in regard to every exposure, as well as the name of the plate and intensifying screen and the nature and dura- tion of development; also the quality of the re-ultiim plate. At first it may be better to vary the time of exposure in the different picture- of the same patient instead of haxardinu' them all <>n the time estimated to be riiiht. Yerv -non one has a record from which one can find an expo lire which has .riven a perfect result fur a previous patient with the same weight and measurement as the case in hand. And later one may compile a table like the author'- which i- merely given a- guide tor u>e while acquiring one's Xoft '. Author'- i- found on pa tie S ( ,)S. \i>f< (]. Sn/nal for Patient to //. Hr<(itf>.- In gastro-intestinal radiography it i- indispensable thai the patient >h<>uld not breathe dunnir the expo-ure. The author ha- a doorbell fastened on the out- side of his .r-ray-proof booth which i- runii by turning a handle inside the booth. The patient i- told that at fir-t lie will hear the -oiind of the machinery, and that when the bell riim- he i- to hold hi- breath until the operator iiives a second -iiiiial. when he can breathe, but not k the apparatu-. ail Print* / <;od print. This may he of the -ame size as the plate, hut it is verv much the author's custom to have a professional photographer make ."> x 7 or S \ 10 inch reduced mounted prints on ulossy paper which -how all the details like a steel oimravinii, and are hound together as a folio of convenient si/e for studying the entire series and for lilinu away for reference. If the photographer has the equipment assemhled for daily use these prints cost loss than the large ones. \<>tt S. Duplitixed lilms and two intensifying screens are very tlesirahle Tor Castro-intestinal radiography. IMPORTANT LITERATURE UPON RADIOLOGY OF STOMACH AND INTESTINES 1 lol/knecht ami Case, Amvendung dor Stereoskopie fiir die Rfmtgenuntersuchung de< Mairens und Darmes. Vereinsbericht, Mi'mcli. mod. Wochenschr., 1911. S. 280"). I\:n-tli'. Die Thorerde Thorium oxydat. anhydr. uns\v. Miinch. med. Woehon- . Haudck. Zur Rcintgonologischon Diagnose der I'leer itionen in der Pars Media des Mairens. Mimch. ined. Wochenschr., 1910. Nr. 30. Hol/.kneeht, Die neueren Fortschritte der Rontgenuntersuchung des Verdau- uimstraktus. Berl. klin. \\'ochensehr., 1911. S. l."),s. Kae>tle, I'her Mageninotilitiitsprufung mit Ililie der Rontgestrahlen. M.iinch. med. \\Ochenschr.. 1907. I'fahler. The Rcmtgeii Rays as an Aid in the Diagnosis of Carcinoma of the Stomach. .Jour, of the Anier. 'Med. Assoc.. 1909, Hd. lii. Nr. 11. Pfahler. Roentgen Rays in the Diagnosis of (lastrieand Duodenal Ulcers. Amer. (^uarTerly of [{oentgenology, iv, Feb., 1913, No. 3, p. l.~>ii. Ried'er, Rontgenuntersuchungen des Magen> und Darnies. Miinch. med. \Vni-henM-hr., 19011. Xr. 3. Rieder, Das chronische Mjigengesclnviir und sein r(intgenologischer Nachweis. Muneh. med. Woclienschr., 1910. Nr. 4S. ! laetii-ch. Die Rontgenuntersuchung bei \"erengmiiren des Dickdarms. Rontgen- olnuisclie l-'ri'ihdiamiose de> 1 )ickdarmkarzinoms. Miinch. med. Woehenschr.. 1911. S. Uaudj-k, I), r Radiolouisclie Nachweis der rieusduodeni. Med. Klinik, 1912. Xr. Hul/knechT. Die Xonnale I'eristaltik des Colon. Miinch. med. Woclienschr.. 190'. i. Nr. 17. .Itiii.-i-, S.. I 'ber die Abhaniritdieit der Darmnn it ilii ai vom \"erhalten des Magens 11 \ - tPii Magen-Darmkanales u>\v. l'"ortschr., Hd. niittel- Rntitgen-trahlen. \\Cin.med. perative Thel'aple L r e\\'l--ef \ h \Verer ( >b.-1 ipat ion. mobili' und diri mi~clie Ai)p''ndicii . Kmmr der I) g nd f .''onard. The Ri'int tr-n Diatr URINARY CALCULI I rmar\ i-alcuh m;i\- very otten he -hown m ;i radiolli\'e proof thai they are ;ih~c]it. lor -oine oi them. con>i-imti ot iriahlo pure uric acid, have such slight density that they make no contrast with tin- tissues. The denser varieties, even il <|ititr .-tn;ill, show well in ;tn\' picture in which the detail (A the vertebra 1 , their bodies, spines, and t raiisver.-e ;md vertical processes, can be seen together with the last ribs and the quad- I'atus luniborum and psoas muscles. To obtain such ;i picture \\ith- out danger to the patient requires the most perfect technir and fir.-t- dass ap|>arat us. One should hesitate to at tempt such a pict ure unt fl lie has acquired such practical experience with the .r-rav that lie i- able to secure excellent radiographs of less dillictilt jiarts witli a mod- erate st relief h of cui'rent and with sliort exposures. The first case that one colleague attempted \\as exposed for six minutes, nothiim on the photographic plate; and again for sixteen minutes without anv result except a severe burn. To secure a good picture of this region every time, instead of occasionally as a sort of accident, it is necessarv to be able to properly excite the ./--ray tube. Kvery word in the chap- ter on general radiographic technic should be known b\- the operator and verified and mastered by repeated experiment. The effort should not be to take radiographs in the shortest possible time, but rather to take the best possible radiographs and in the safest possible wav. Calculi may be in the pelvis of the kidney, in the ureter, or in the bladder, and two different positions of the patient are desirable 1 . For those in the kidney, or in the part of the ureter above the brim of the pelvis, the patient should be lying upon his back with the plate 'measur- ing 14 x 17 inches) placed longitudinally beneath him from the tenth dorsal vertebra to just above the trochaiiter. The patient'.- knee- should be raised and the 1 feet rest against some support, the effort being to bring the lumbar vertebra^ into contact with the plate. A large fat person is very much more difficult to radiograph than a small thin person. The difficulty does not appear to be so much an impenetrability of the body, as a very, much increased diffusion of the .T-ray, or, more accurately, an increased production of secondary rays. The use of a diaphragm and cylinder to cut off the secondary rays from the .r-ray tube, with or without compression, is of great service in overcoming this difficulty. The thickness of abdominal tissue through which the .r-ray mu-t penetrate may be diminished in three different ways: One is by the use of an air-filled bladder, which is pressed upon the abdomen by a belt passing over it (Caldwell), another is by the use of the compres- sion cylinder \. \lbers Schonberg:. and the third is by the Use of the 'Hit hor's board com j iressor. The compression cylinder (Fig. To.) produces an excellent picture, bill one not more than or s inches in diameter, and hence a single picture 1 does not irive conclusive result- in cases in which the position of (lie calculus or even its very existence is no! known. The Board Compressor. 1 Fqually good detail is obtained with tlu 1 author's board compressor, and it has the very great advantage of producing a picture the full sixe of a 1 IX 17-inch plate. It consists of a board of white wood 1, inch thick. Ill inches wide, and IN indies long, which is reinforced at either end by cross-pieces ,',,- inch thick. The cross-pieces are '2 indies wide, are beveled toward the middle, and are glued, not nailed, on. Two holes are bored through each of the reinforced ends for cords pa--ed under the table. The board 1 Tuuscv, Louisville Medical I'p>mv~. November. 1 '.>}. 1050 MKDICAL ELECTRICITY AND UONTOKX HAYS ~" " IL'. 7M I. Renal radiography \vitli a coinpies.-ion cylinder. The knees should lie drawn up and a pillow placed under the shoulder.- a- in Flu. 7 ''>'>. I'enal radioL'raphv with eonipre-.-iim band, under which is an inflate* ne to pui the plate in exactly the ritlht it] ii ; late tun . ' r t he iiat ient and to i'li:i ni/e i' for -i ' "plntr- tunnel." Stroim enotiirh to -u.~tain the patient's !,'-./ rav. Sr. lari. r e tliat the plate, u, it - Imlder \\ it 1, ,,\- without . itii inei i wit hout ino\ ini: lli' pa i i> ill THE Z-RAY 1051 pressed tightly across the abdomen (Fig. 735), making a reduction of 2 or 3 inches in the thickness through which the x-ray must pass, and is itself perfectly transparent to all but the softest' rays. As these rays are the ones which produce dermatitis the board compressor fur- nishes an element of safety. The coniitre.wion band with an inflated rubber ball is easily and quickly applied (Fig. 735). This is better than the board compressor. Heavy tungsten target tubes are necessary for this work, the ( 'ool- idge tube being excellent. A 14 x 17 inch plate is placed lengthwise under the body, with its center 3 inches above the umbilicus. The x-ray tube is placed with its anticathode over the umbilicus at a distance of 23 inches from the plate and inclined so that the principal ray is not vertical but is directed toward the center of the plate as above described. The best results, quire a small diaphragm and only one kidney ith a as-filled tube r own. With the (' e, however, the author . , , ses no diaphragm, but exposes the whole of the I I \ 17 inch plate at once. In patients, however, with a very marked disparity between the waist and hip measurements the exposure requires to l.e equalized by the author's graduated .r-ray filter, reducing the intensity at the level of the umbilicus and for a few indie- above and below that. This i- -eldoin required for men, but frequently for women. The exposure table on page S ( ,)S i> ba-ed upon the use of rays cor- responding to a (-inch spark and upon i he use of an intensifying screen. The latter may be dispensed with in patients so thin as to need only short exposures, but the time would then have to be about two and a 10.J-' MKlHi Al. Kl.Kl TKK1TY AM) KONTCJEN KAV Before applying compression band and l>:ill for renal radio<;rai)hy. hall times as great. This would lie undesirable for the heavier patients because the very long exposure with this quality of .r-rav would over- heal the tube and require the patient to hold his breath too lon<>. The examination should only be undertaken with the stoniaeh and intestine perfectly empty as far as solid food or any milk pr< dud is concerned. The tube must be excited in >uch a way a> to produce a brilliant radiance, as viewed with t h LI Horoscope, and the vacuum ouht to be 40. Compression relaxed after the renal radiograph has IMTII mad shows what compression had been exerted. Patient mu-t -ay when thf pressure i- all h medium, resistance about 4 inches. The distance from the target to the plate should be 2o inches. An intensifying screen should be u>ed, and for an ordinary 150-pound man an exposure of '.\\H) ma. seconds, for example, 30 ma. for thirteen seconds (see exposure table for sex. weiuht. and measurement variations, page 898\ \Vithoii1 an intensify ing screen a ")-inch back-up and the same exposure an- u-ed. A very hut off during si long weak exposure in time to prevent t lie t ube t n>m lieconiing overheat ed and after a minute's pan-^e l urned on auam. It will be remem- bered that t here are t wo danger- from overheating the ant icathode max be burnt through or the vacuum may become excessively low. It is wise to have a not her t ube in readiness and to wat ch the behavior of t he tube 1054 MEDICAL ELECTKICITY AND RONTGEN RAYS in use. If the tube becomes useless the second tube should be sub- stituted, taking care that its anticathode shall be at exactly the same point, directly above the umbilicus, as the first. For the bladder and the portion of the ureter below the brim of the pelvis the patient lies Hat on his back, with the limbs extended, and sufficient cushions under his hack to tilt the pelvis somewhat forward. The anticathode should be vertically above a point o inches below the umbilicus. In this position the rays pa-s down through the pelvic canal, and any cal- culus present is seen free from the shadow of the bones. The distance of the tube from the plate, the degree of vacuum, and length and in- tensity of the exposure an 1 the same as for renal calculi. The com- pression board is used. Following the author's almost invariable practice in radiography a shield of .r-ray metal (tin and lead) is placed behind the plate to shield it from secondary rays arising from the Wood or other parts of the table or from different objects in the room. Riddel 1 uses the fluoroscope as a preliminary to radiography in examining for urinary calculi, but this is extremely dangerous. The plan of having the patient lie face do.vn upon a canvas stretcher or thin board table, with the tube underneath the abdomen, enables one to make a fluoroscopic examination for renal or ureteral calculi. The iluoroscope is held over the patient's back. The tube may be held by the orthodiagraph, or it may be completely enclosed in an opaque shield, such as Ripperger's. I'sing the latter with the largest diaphragm and the anticathode at a distance of 25 inches from fluorescent screen, the whole of both kidney and ureter regions and the bladder become visible at once. Any large calculus may be discovered by an eye trained to thi- phase of fluoroscopy. and may be subjected to more exact scrutiny with a smaller diaphragm or cylinder, or with the author's cellular diaphragm. The protective shield prevents injury to the operator's limbs or genitals, and, if the room is entirely darkened and the fluoro- scopic screen covered by a sheet of lead-glass, his face and eyes are also protected. A radiograph may be made of the whole region, or a smaller one, with a diaphragm or cylinder, may be made of a stone located by iluoroscopy. The dangers to the operator are so great that even these precautions will not make it safe to use frequently. The danger to the patient must be remembered, and, if the localiza- tion of a calculus with the fluoroscope is evidently going to take more than a very few seconds, the operator should stop and at once proceed to make a ra< liograph. This prone position produces more or less natural compression of the abdomen, and the compression may be increased by placing an air-bag of some kind upon the table under the abdomen. Compression by the compression cylinder is not practicable in this position. ir the Madder and the lower part of 1 he ureters the plate is placed he center is .'! inches below the umbilicus and the icy, and a 11 x 17 inch plate is Used and the - center. The compression band and bag e -ame possible desirability of the author's |Uali/.e the expo-ure if the waist i- Locations in Which to Look for Urinary Calculi. Renal calculi . - . found near tin- an r.l.-i-L'mv M.-. THE X-RAY 105.-) to the border of the spine. If they are much below this region, it is because of displacement of the kidney, and suspicious sh;ido\vs beyond the tip of the twelfth rib ;ire almost always of intestinal origin. Ureteral calculi are most often found below the brim of the pelvis. The course of the ureter may be indicated by a line starting 1 inch internal to the spine of the pubis and extending to the sacro-iliac synchondrosis. But this position miuht be misleading in case of a calculus sacculatcd at some distance from the ureteral lumen (Tilden- Brown). A radiograph made with Ihe tube over a point midway between the umbilicus and the symphysis pubis, and with the anticathode [ ig. ill. Iso of FOUSPV s radiating cellular rhanhraprn in radiography nf renal calfuli. Weight of patient, 15tone was lodged at the junction of upper and middle-third- in one case, 2 were lodged at the lower part of the middle third, and (i in the lower third of t lie ureter. In Haetjer's .'$.")! cases examined for urinary calculus only o ca-es revealed a ureteral calculus lyinu; above the brim of the pelvi-. 1 Boston Mi-.l. ami Surt; Jour . ]'.'<)'>. MKDICAL Ki.KrTKKiTY AND RONTGEN HAYS The Use of the Cylinder and Diaphragm in Radiography of Renal and Ureteral Calculi. A small cylinder, 3 inches in diameter and 7 inches long, extending from the surface of the patient's body to the localizing shield, or opaque box enclosing the .r-ray tube, makes the di.-tancc- from the anticathode to the photographic plate about 2~> inches. The- diameter of the picture is (j inches, and a really wonder- ful improvement in definition is obtained compared with the results when no diaphragm at all is used. Careful study will enable one to secure a picture of the exact region of the kidney, an S X 10-inch plate being required. By applying the cylinder at first a little to one side of the median line, and then to the other, both kidney regions may be radiographed without exposing the same tissues twice to the x-ray. A single radiograph with the same small cylinder in the median line and 2 inches above the symphysis pubis. and tipped a little downward, will show the whole cavity of the pelvis and reveal calculi in the bladder or in the pelvic part of the ureter. One made with a cylinder 5 inches in diameter in the median line. 3 inches above the symphysis pubis, will show the middle portion of both ureter. 1 . Stereoscopic radiography may be occasionally used in the differ- ential diagnosis of renal calculi. Filling the bladder and rectum with oxygen gas still further increases the clearness of the image. It is rather important to make certain that the patient has not been taking bismuth for a few days before 1 such an examination. This would cause a shadow which might be mistaken for that of a calculus. Dense cicatrices in the kidney have been seen by Baetjer to cause suspicious shadows similar to those of calculi. Dark shadows on the plate or light areas in the print, presenting a size, shape, and position suggestive of urinary calculi, must not be mistaken for them. They may be due to one of two different causes: fir.-t, an imperfection in the plate; second, a collection of gas in the rectum or some other part of the intestines. These shadows represent areas of reduced resistance to the .r-ray, and cannot, therefore, be due to calculi, which, of course, cause increased resistance. The last ribs, the crest of the ilium, the transverse processes of the lumbar vertebra-, and the edge of the psoas muscle should all be clearly defined in a radiograph to fit it for the diagnosis of urinary calculi. Differential Diagnosis of Urinary Calculi.- Very often, but not al- ways, one can be sure from the location and form of the foreign body that it is a renal or a ureteral calculus. One means of value in case of doubt is the author's method of localization of foreign bodies. Applied in the case shown in Fig. 712 this showed the foreign body to be 3 inches from the plate and in the- kidney shadow. This proved that the foieiu-n bodv was in the kidney. When ureteral calculi are apparently -hown an opaque ureteral catheter is introduced and two radiographs made with the tube displaced laterally. If the catheter is in the same i-lo-c contact with the foreign body in both radiographs the latter is do ibtle-s in the ureter. Figure 713 showed that the concretions were not in the ureter, but were doubtless phleboliths and not responsible t' >r t he p.-i t ient 's symptoms. Penetrability of Different Kinds of Calculi. The order of pene- trability ! v the /-ray is: 1, Biliary calculi; 2. uric acid calculi; 3, phos- pha ' ic c-i l.'uli ; 1 . calcium oxalate calculi. Th'1-r |e.-|st permeable, like the calcium oxalate calculi, cast the deep,-; -h:ido\v-. and are the most easy to detect. I'ric acid calculi cast faint shadows, but can almo.-t always he detected in a successful radiograph. I'hosphatic and calcium oxalate calculi cast dense shadows, and can always he ,-een in a .-ucce.-sful radiograph unless they are very small. A calculus .-mall enough to be passed in the urine may e.-cape detection by the r-ray, e.-peciallv if the pat lent is lar;e or stout . The order of permeability corresponds fairly well with the specific if the patient is larjre or stout. ('ystin and xanthin calculi have shown perfectly well in a num- ber of radiographs by Morris. 1 This may he due to the fact that many of these calculi contain calcium, maune-mm. and ammonium phos- phate, and 1 hey will contain '2't per cent, of sulphur. Phleboliths.- These small concretions are very apt to occur in the veins o! the pelvis, and can sometime.- be seen in a radiograph. Their shadow- are more definite and then edsie- are more sharply de- fined than those of a calculus, and they are almo-1 always very small. They lie close to the line of the ureter at or helow the brim of the pelvi-. 1 Lancet. July L'l, I'.Klti. 157 1UO MEDICAL ELECTKKTTY AND KONTGEN KAYS In cases of doubt another radiograph should be made with a ureteral catheter in position. The phlebolith will be found to the outer side of the catheter. A soft flexible ureteral catheter has been devised by Fenwick, and has also been used by Howard A. Kelly for cases of this kind. It contains a certain percentage of bismuth, and is safer to use than 1 iir. 74I-1 h of un'tcr.-il catheter- dcmoiist nitinir plif.-l i Jit hs, not im-tora! cal- a c;jt hetrr with a mHal >ty]et. A cat heter int o which a cert ain amount "t niftnllic mercurv h;i- been poure-d is equally good tor this purpose, - tint -d -implc as the catheter impregnated with bismuth. The Ureteral Catheter in Radiography. A ureteral catheter rendi-fcd .p.-tque ;is above may be int roduccil ;i> ;m ;iid in the 1 radio- gi'aphir d];iLi!ii i-i- of ureter;d ;ind renal condition-. iJamskj' used this mrtliod -Hi''-'----! i|]|\ in _' most interesting cases. In one patient a sim- ftn. .lulv !, I'.Kl."). THK .f-KAY 1059 pie radiograph had shown a kidney-shaped body. The radiograph, made \vith a ureteral catheter and stylet in position, showed that these did not pass into th' kidney-shaped body. It was concluded, therefore, that this Avas not the kidney, and upon operation it was found to bo an ovarian cyst with an extremely long pedicle. The other ca.-e was that of a woman with a ureteral fist ula following the removal of a uterine fibroid. A radiograph, made with catheters in both ureters and the fistula, showed which ureter had been opened and at "what level. A ureteral catheter containing metal wire will show in a radio- graph. Pransford Lewis' reports a case in which three ureters were demonstrated in this way. The ureteral catheter will also aid in deciding whether a shadow on the plate is due to a calculus or to something outside of the ureter. Fen wick 2 reports cases in which the radiograph showed bodies apparently in the ureter, but a second radiograph with a ureteral stylet showed that such was not the case. The operations showed that the shadows were those of calcined lymphatic glands or arteries. Technic of Ureteral Catheterization (Dr. Palph Tousey. Personal Communication). The catheters are >1erili/ed by washing with green soap and water, placing them in soon bichlorid of mercury for an hour or two, then in 2 per cent, boric-acid solution. They are dried and kept dry. If they are to be used soon keep them in boric-acid solution. The stylets may be boiled or passed through an alcohol flame and kept temporarily in boric-acid solution. The metallic in- struments are sterilized by washing in alcohol. Local anesthesia is secured in 1 he female by filling 1 he uret hra with '20 minim- of ^ per cent, solution of cocain from a hypodermic syringe without a needle, leaving the solution in for three minutes, and in the male by the instillation of ."> or !() minims of 1 per cent . sol ut ion of eucain in the prostat ic urethra. ( dycerin is used as a lubricant. For the Xit/e type of cystoscope, for instance, the Brown-Buerger, the patient is in the dorsal position, with the legs supported by crutches. Six ounces of 2 per cent, boric-acid solution i- injected into the bladder through a flexible catheter, which is withdrawn, and then the catheter- i/.ing cystoscope is introduced. The perforated caps of the latter are already provided with the two catheters, the other end.- of which are held at a higher level by the patient or nurse. The orifice of one ureter is to be sought obliquely outward and backward \\ inches di-tant I ron i the urethra, and a number of blood-vessels will be seen to radiate 1 from it. Push the corresponding catheter in until its tip is seen, and further, until the tip di-appear- beyond the field of vi-ion. See the ureter, bend up the catheter with the lever provided for the purpose until the tip of the catheter is seen; pu-h the entire instrument toward the catheter and the catheter will probably enter the ureter. When in pu>h the catheter a couple of inche.- further into the ureter, and -wing the instrument over to the other side and introduce a catheter into tin 1 other ureter. The urine may be collected in two sterile test-tube- for ten or fifteen minute-. Pu-hinu the catheter.- in. the pelvi- of the kidney will be entered at a di.-lance of about ^0 cm. from the internal urethral orifice; this will be evidenced by a certain obstruction, also perhaps by the ex-ape ot a dram of urine at once instead of the ureteral peri-tal-i-. The capacity of the pelvi- i- about 2 drams. 101)0 The Howard Kelly cystoscope is simply an open hollow cylinder introduced into the air-filled female bladder and directly exposing the ureteral orifice, which appear- of its natural si/e instead of being magni- fied eight time-, as in the Brown-Buerger cystoscope. Patient on her back, with feet in Mirrups. cocain is applied, the bladder is emptied by a catheter, the urethra is dilated by passing No. 20 Hanks cervical dilator. Then the knee-chest position is assumed, buttocks on a plumb- line with the calve>. thighs a little back of the perpendicular. Draw back the perineum with the finger to allow the vagina to balloon out : in some exceptional cases introduce a rectal speculum for a moment. Introduce a Kelly cystoscope. 25 French, with electric-light attachment. 1 )epre-- handle, bladder filling with air. Draw out to internal urethral orifice, then push in for I 1 , inch with a lateral deviation of 30 degrees and see t he orifice if < me ureter. A- a prophylactic after cystoscopy 2 ounces of 2 per cent, solution of protargol are injected into the bladder. In case of doubt the author makes two radiograph- from somewhat different directions. ( 'oincidence of the shadows of the ureteral catheter and foreign body in both pictures shows that the foreign body lies in the ureter. I)<-i'(-lopment of the plate to show renal calculi, (i. Thurston Hol- land/ working with an induction-coil, mercury interrupter, and an ex- posure of five to twenty seconds with a primary current of 7 amperes ami an I If on 1 .r-ray plate, found that six minute-' development was best . The Ilford metol hydroquinone formula was used and the finished and dried plate was not blackened, but white and lliin and easily seen through by daylight . The detail- of the abdominal tissue- and the vertebra 1 and iliac crest- should be quite clear. This, it will be seen, is decidedly differ- ent from the development commonly given a -creen plate of the stomach or inte-tine- containing bismuth, which i.- so much denser than a renal calculus and where the plate is usually decidedly blackened. Results in Renal and Ureteral Radiography. A mistake in diagno- si- i- po--ib'le in exceptional cases even in the most expert hands, but in general it form- an extremely reliable ni"ans of diagnosis. Pirown'-' mentions a case in which the radiograph failed to show a iireteral calculus which could be seen with the cystoscope. and which was subsequently removed bv an operation. Lydstotr reports several cases of ureteral and renal calculi removed by operation. >ome of these were found in the skiagraph, but in fully as manv other cases 1 hev were not. The r-ray uave negative results in a case reported by Ware. 4 The i--i->' was one ni contracted bladder, and ai a postmortem examination a -lone was found in each ureter close to the bladder. I he late 1'iMen Brown 1 ' found that in cases of pure uric-acid stones a live radiograph was as likely as not to be returned by the ratliog- raphcr. ami tin-, too, in subjects of favorable pro port ions and where t he iii'e-imal contents are thorotighlv removed. lifi'ii It.iv. Jan.. I'.Mi'.i. N ^ M'-'i.. A'-.d'. <;. T. Section, ( )ct. 17, I'.HK 1 ,; Jour. AIIHT. Mcd. Assoc., Doc. i.'. I'.MMi. |, 1J01. I" .' \ , ' M< .] V-MC . I'.XIf,. ' ' : J.-ir . M.-.n-l, :',!, I'.tO'i. ,,. list THE .T-KAY 1001 Baetjer 1 reports a successful use of the .r-ray in pract ically all of '.]')[ cases examined for urinary calculi. The author's own cases include a number in which a positive diag- nosis of calculus was made from the radiograph. All but one of these are known to have been operated on and the calculi removed. The one case known not to have been operated on made the most beautiful picture; of all. The patient was referred to the author by Dr. I.eroy Broun, and a radiograph showed a collection of stones, like a bunch of grapes, in the left kidney. Since the pain and tenderness had always been on the right side, a second radiograph was made, placing a dis- tinguishing mark on the right side of the plate. This again showed the group of calculi in the left kidney. The pictures are decidedly different, showing either a different grouping of the calculi or a differ- ence in their position relative to that of the .r-ray tube. Dr. Broun lost sight of the patient for a number of years because the man was afraid to be operated upon. A radiograph (Fig- 741), made at the end of that time, showed a similar condition. A curious case of the author's was one in which the radiograph showed a calculus which the operator, Dr. Gallant, 2 found embedded in the mesentery 2 inches from the ureter. It had all the character- istics of a ureteral calculus. Another case had been subjected to thirteen x-ray examinations before being brought to the author by her physician, Dr. W. Travis (libb. Six or seven of these had been made in Kngland, and revealed a ureteral calculus which had been passed spontaneously. The re- mainder of the radiographs had been made in America. Xone of the entire thirteen radiographs showed a renal calculus, although there were well-marked symptoms of such trouble. This kidney was known to be prolapsed and the other kidney had been removed. The radio- graph was made in the author's usual manner, without any extra intensity of radiance or extra length of exposure, and revealed the presence of a large renal calculus, presenting two horn-like prolonga- tions downward. Smaller pieces were visible around it. 1 he stones to cor- Should the Surgeon be Given the Radiograph or Should He Simply be Given the Radiologist's Report of His Examination?- The last case is, one in point. The radiologist who had made the last examination previous to my own had refused to let the surgeon have the radiograph, but simply stated that it showed that no stone was present. The subsequent result showed that this opinion was incorrect. and that if it had been acted upon the patient would have been left to suffer from this very painful condition. It is. I believe, the opinion of a majority of the active members of the American KontL r en Kay Society that the radiologist is to uive from which the surgeon can make his. theory that the radiograph requires, his opinion and not a pic 1())2 MEDICAL ELECTRICITY AND K(")NT(iEN HAYS radiographs of the different conditions which ho is called upon to treat, and should be able to judge of the quality of the picture. If it is a mere foggy daub, when he knows that a good radiograph should show the lateral processes of the lumbar vertebra" 1 , he is not obliged to take the radiologist's diagnosis and run the risk of performing a serious operation uselessly or of neglecting to perform an operation in a case which requires it . The surgeon will doubtless accept the radiographer's diagnosis in almost every ea.-e. but he should have every opportunity of knowing \vhether this opinon is based upon a successful radiograph or not. In some cases the surgeon has made a special study of the radio- graphic appearance of a particular class of lesions, and his opinion may be even more valuable than that of the radiographer. The author has learned a great deal from friends who have sent him cases to be radiographed because they have not the time to devote to the technic manipulation of ./--ray apparatus. In one case of the author's two plates wore exposed at the same time and both showed excellent detail. One showed an image like that of a calculus somewhat below and external to the region of the kidney. The image did not show on the other plate, and the proba- bility seemed that it was due to some defect in the first plate. Dr. Douglas II. .Stewart operated, however, and found a calculus in the posi- tion indicated by the first plate. A considerable number of cases have been examined by the author in which the radiograph showed no stone in the kidney or ureter. As far as he knows, none of these cases have been operated on and, there- fore, it is impossible to say whether the negative diagnosis was correct in all of these or not. The late ( 'has. Lester Leonard and Lewis ( iregory Cole have reported a large number of cases examined by them for renal and ureteral calculi with excellent results. Leonard formerly gave a long exposure, four or five minute-, with a moderate intensity of radiation, but later used a transformer and an exposure of only a few seconds. Cole uses a short expo-ure, about half a minute, with great inten-ity. A- to the degree of penetration, the late Dr. ( 'aldwell used a ray wit h which t lie bones of the hand appear gray. (The use of the hand as a radiometer is a most dangerous practice.) Some of the author's best radiographs of the pelvis and lumbar reirion have been made with a penetration of only Xo. 4 Benoist, with which the bones of the hand would appear almost black on fluoroscopic examinat ion. < IMP ca.-e was examined for calculus, and the very distinct image of the kidney was regarded as sufficient evidence, taken together with the hi-torv of the case, to require an exploratory operation. The operator. Dr. Tucker, found a prolapsed kidney in a state of chronic r mmation. requiring removal <>f the entire organ. There were no ud no calcareous foci. HYDRONEPHROSIS - ease produces an abnormal appearance in the radiograph. An area of opacity may be seen to begin in the kidney region and ox- tend ' ; and perhaps inward from it. It.- regular, sharply- ilefincd, conv . bonier and largo size are its chief characteristics. These THK X-RAY may not enable one to make more than a probable diagnosis of hydro- nephrosis, but they do exclude renal calculi or biliary calculi (a.-: the sole lesion), tuberculosis of the kidney, or intestinal obstruction. Report on the Radiographic Findings in a Case of Hydro- nephrosis. The patient was sent to me through the kindness of Dr. Beaman Douglas, (lull-stone disease \vas suspected from the symp- toms of attacks of pain and tenderness and from the presence of a tumor in the gall-bladder region. A radiograph was made after an ordinary dose of Kochelle salt, and another a fe\v days later, after very thorough purgation by llunyadi water and fasting for twenty- hours. The following is an abst ract of my report on the radiographs: "The two pictures are practically identical. They show the ab- senc? of any lenul, ureterul, or vesicul calculus, and they show an area of quite dense opacity, extending downward and inward from the right lobe of tin' liver to the median line at the level of the crests of the ilia. The right-hand border of this area of opacity is very sharply defined, and forms an unbroken line, which makes the right side of the abdomen in the radiograph contrast greatly with the left side. We see on the left side a more or less irreu'ular and broken border to tin- shadow of the abdomen. The area of opacity on the right side obscures the lower ribs on that side and also a part of the vertebra;. A mass of gall-stones would not be expected to cast so decided a shadow, and certainly not one with such a clearly defined border. The opacity would indicate the presence of either a large 1 sac of fluid or of a solid tumor. There appears to be very little doubt as to the necessity of surgical exploration in this case. It cannot be stated whether there an 1 any gall-stones present at all, and they certainly do not form the bulk of the swelling which is felt on abdominal palpation," The operation, performed by a surgeon in Portland, Maine, evacu- ated a lunre sac of fluid, which at first appeared to be a retroperitoneal cyst, but from which urine began to flow in a few days, proving that the trouble was hydronephrosis. PYELOGRAPHY Yolcker and Lichtenberg 1 puss a ureteral catheter into the kidney and inject u warm (5 per cent.) solution of collargol (a silver compound') into its pelvis. The size and shape 1 of the pelvis of the kidney can then be shown in a radiograph. The method is suggested for the diagnosis of dilatation and of deformity of the ureter. PERINEPHRITIS The .r-ray gave negative results in a cast 1 of paranephritic sclerosis operated upon by Berg." HEMORRHAGIC NEPHRITIS Hemorrhagic nephritis was present in - cases reported by Wiener. 3 The radiographs showed no abnormal appearance of the kidney, ureter, or bladder. 1 Munch. Mc,l. Woch., Jan. K>. I'.iOf.. 2 N. "i . Mcd. Jour., Aim. IS. I'toti. 3 X.Y. Acud. M'd. Cfiiito-l'i-iiuiry Section, Oct. 17, 1 '.()'.; N.Y.Mc.l J,, U r Dec. i:.. I'.iOU, p. l'J(H. 1(1*14 MEDICAL KLKCTKKTrY AM) KOVHiEN RAYS RENAL TUBERCULOSIS Tuberculosis of the kidneys, according to Brow.' presents radio- graphic appearances of diagnostic value. Such a kidney casts a well- marked shadow. In one of Brown's cases the .r-ray showed a shadow suggestive of renal calculus, and an operation showed that the kidney was tuberculous anil filled with a putty-like substance. .1. Bayard Clark" and others have reported cases of tuberculosis of the kidney which were diagnosed by radiography, combined with cystoscopy and crvoscopy. A radiograph of urine in a case examined for Dr. K. L. Keyes, Jr., gave positive indications of the character of the lesion. RADIOGRAPHY OF VESICAL CALCULUS Two positions are available. One is with the patient face down upon the plate and the tube in the median line at a lower position, so that the rays will shine obliquely upward through the pelvis and pre- vent the shadow of the sacrum from filling up the entire image of the pelvic canal. In the other position, the patient lies face up upon the plate, and the x-ray tube is in the median line, about 3 inches above the symphysis pubis, the anticathode being at a distance of 17 inches from the plate if no cylinder diaphragm is used, and about 24 inches if this apparatus is used. The rays traverse the pelvis in the same line in both cases, but in opposite directions. The idea is to show the cavity of the pelvis as free as possible from the shadow of the sacrum. The author places the plate behind and the tube in front, but some others prefer the ventral position, on the theory that it brings the plate nearer the bladder and consequently nearer the- stone. As it is better to have the bladder empty, and as the stone is almost always near the neck of the bladder, this reasoning does not seem exactly correct. The author's cellular diaphragm u'ives clearness of definition through this thick portion of the body with a gas-filled tube better than in any i it her way. The exposure should be the same as for the kidney (see Exposure Table, pain- Mv. The rectum and bladder contents should be evacuated, and a much clearer image will be obtained if both these cavities are filled with oxygen gas, A case has been reported in which the radiograph, made in the ordi- . did not show a small stone, which was clearly depicted on a photographic film held in the vagina, just as radiographs of the teeth ; " ; upon ;i film held ii^ide the mouth. -on* s, shown in one of the author's cast's, ] 1;( ,1 ] lo t been discov- : I'.ottini operation for prostatic hypertrophy was performed 1 ".'O : reviously, and consequently no improvement had followed lion. The pat ient, a man of sixty-five, was sick in bed, having irrigated five or six tunes a dav. and suffering great pain. to discover any stone two weeks before t he x-ray exami- '.':. 1 he radiograph showed two large calculi, \\luch were removed ' M by Dr. I'.uck Carleton. He found that the stones .'' i! consistence, which accounted for the impossibility M> : ',. :.!,,-! 'nn:irv Si-dicm. Oct. 17. 1'.>H: X. Y. Mc-1. .lour., [)<] 1 1 i: THK .r-HAY 1005 of detecting them by ordinary means of examination. Since the operation the old gentleman is able to run up and down stairs and rode 100 miles on horseback in one day a year later. The r-ray has actually saved this man's life. Vesical calculi are usually made up of oxalates or phosphates, some- times having a nucleus of uric acid, and are usually of considerable size. Moseley 1 prefers to have the patient lie face down on the plate, so as to bring the bladder nearer the plate. The bladder and rectum should be empty. The bladder and rectum may be filled with oxygen gas, but this is not entirely free from danger, and Saenger reports a fatal case. An encysted calculus in the lower posterior wall of the bladder was found by means of a radiograph by .Menges, and removed by Holmes-'* after systematic exploration with a searching sound under general anesthesia had failed to discover it. It was completely encapsulated. In cases examined for vesical calculus the kidnevs and ureters should also be radiographed. Many vesical calculi originate in the kidney, and it 18 wise to see whether new ones are forming. Beck 4 states that since he has begun to radiograph the kidney as well as the bladder he has found renal calculi in every case of vesical calculus. This observation makes it important to investigate the kidney regions as well as the bladder. Additional observations arc; re- quired to determine whether such a combination is invariably present. PROSTATIC CALCULI A case of this comparatively rare condition, referred by Dr. J. P. McGowan, was readily shown by a radiograph. The patient lay supine upon the plate, the lower end of which was raised to an angle of 20 degrees with the table 1 , and the tube was 4 inches above the sym- physis pubis. This was with the idea of securing an image of the calculus not overlapped by that of the pubic bones. This did not prove to be the case, but the calculus was such an enormous one that this makes little difference. In fact, in this picture the image of the stone completely overshadows that of the symphysis pubis. \Vhether the object could be obtained by placing the tube at a considerably lower level than the symphysis is not known by actual experiment, but it seems probable. If so, the- stone would cast an image below the arch of the pubis, but overshadowed by the image of the sacrum and coccyx. Considering also the 1 possibility that the calculus might be in the bladder instead of in the prostate, the position adopted in making this radiograph seems the most desirable one. Figure 744 is a radiograph made with the author's radiating dia- phragm of this calculus after removal, and Fiti. 71.1 is an ordinary pho- tograph of the calculus held in the hand and with a scale graduated in inches for comparison. The xiniintil reticles have been shown in radiographs made after injection of 5 per cent, argyrol solution." lOtili MKDU'AL KLECTHIC1TY AND RONTGEN RAYS Fiu f - 714 Radiograph of prostatic calculus izc). Radiating calculu.- alter removal (scale of inches crllular diaphragm employed for comparison i. (Case examined for FOREIGN BODIES IN THE PELVIC ORGANS Foreign bodies in the bladder, vagina or uterus, or the rectum are well shown in a radiograph of the pelvis made with the plate under the patient and the tube over the median line \ inch above the symphysis pubis. THE PELVIC BONES The pelvis is well shown in a picture made as for vcsical calculi; but ior the sacrum and coccyx especially the pelvis is tilted forward, and the tube 1 is just above the level of the symphysis pubis. The compression board and the cellular diaphragm are used and the other conditions are the same as for renal calculi. Non-union of the Symphysis Pubis. This condition as a con- genital defect was found in a case of epispadias reported by Mouratoff. 1 The radiograph showed that there was an absence of union between the pubic bones, and that the symphysis was a relaxed membranous barrier. Separation of the Symphysis Pubis. This injury is not so very rare as a complication of difficult parturition and can be recognized ii. ;i radiograph. Radiography of the Symphysis Pubis and Its Normal Appear- ance. The radiograph may be made with the tube in the median line, ,-ind about 1 inch above the symphysis, with the plate under the of the pelvic The distance from the anticathode to the plate iio'ild be ,-ib-iiich resistance. oO ma. for ten seconds an inten-ifyiniL or any other MOO ma. second exposure for an I .")H-p( iinif | man; 1-inch back-up and same exposure with an inti'i . -creen. The radiograph U likely to be a good one Roii.-vkv Vratch., .lulv 'JO. 1 '.>_>. THE ar-UAY in spite of the fact that the part to he depicted is at a distance from the plate. Another position is for the patient to lie face down upon the plate, the center of which is under the symphysis puhis. The tuhe is in the median line and at a lower position, so that the shadow of the sacrum will fall at a higher level than the symphysis. The idea is to have tin- ray pass along the same line as with the patient in the dorsal position, but in the opposite direction. Kven in a patient sixty-five years old the symphysis shows normally a complete line of separation, and it may happen that in a perfectly normal person of any age the radiograph may show an apparently considerable separation. The knowledge of this fact will enable one to guard against the error of mistaking a normal for a pathologic con- dition in the symphysis. Fracture or Dislocation of the Coccyx. It is suggested by the author that a clearer radiograph of the coccyx and lower part of the sacrum may be obtained upon a photographic film held inside the vagina, just as radiographs of the teeth are made upon films held in- side the mouth. A fracture or dislocation of the coccyx could be very easily and beautifully shown in this way if present, while a mere sprain would not present bony lesions and would be diagnosed by exclusion. The rectum should be empty. The Lumbar Vertebrae. Examinations of the lumbar vertcbne for fracture or tuberculosis is practicable and reliable by means of the technic recommended for renal calculi. Radiography of the Fetus in Utero. The fetal head shows well when it occupies the lowest part of the uterus, to the practical ex- clusion of the liquor amnii, but when the head occupies the fundus of the uterus the surrounding fluid produces so much dispersion as to make the radiograph unsatisfactory. The fetal bones arc small and almost entirely cartilaginous, so that it is difficult to distinguish them in a radiograph before birth. The possibility of destroying the vitality of the fetus, or of pro- ducing sterility through action upon the mother's ovaries, should deter one from making repeated .r-ray examinations during pregnancy. A'-ray Diagnosis of Pregnancy and of Extra-uterine Gestation. A radiograph of the pelvis will be of service in either of these con- ditions. What is found is apt to be a silhouette of the fetal mass rather than a picture of its different bones. Lichonstein 1 describes a case of extra-uierine pregnancy with mummification of the fetus. The diagnosis was made by means of a radiograph taken with a medium soft tube without a diaphragm and an exposure of one and three-quarter minutes. The maternal pelvis showed sharply, but the lumbar vertebra- were not so distinct. Over the right rim of the pelvis two fetal extremities were- seen, one being a part of the thigh, r.nd the other, at an angle with this, being the leg. The ribs showed as a striped area on the other side of the mother's pelvis. A pelvis presentation was diagnosed, which was verified by operation. Dermoid Cyst. This condition showed very well in a case referred to the author by Dr. John M. Keyes. 1 Miinrh. Mol. \Voch., vol. vi, s-24. ions MKIM< AL KLK( THIC1TY AM) KOXTCKN HAYS THE HIP- JOINT Dislocation, cither congenital or acquired, and fractures of the neck of the femur are well shown by a radiograph, but the use of the fluoro- scope is not to lie recommended. For a radiograph the patient may lie either prone or supine, the limbs are extended, and the compression band is used (Fig. 740). For a picture of both hips he lies face up, with the plate under the back of the pelvis: the anticathode is directly over the median line, 1* inches above the symphy(> ( . The author'- contact diaphragm should lie used in con- 'enter 1 inch internal to the trochanter. The atiticat hode of the .r-ray ' ilic i- vertically o\'er the center of the plate, at a distance of 12 o inches ! n >m it. Tin- tube -hoiild have a heavy target, the ;'>() ma. ( 'oolidu'e tni tube be'ui'i excellent, but longer expo-ure- than fifteen seconds interruptecl to avo'nl overheating. The exposure for an v blO-poiuid man would be .l-mch sj)ark, Ml) ma. for fourteen ond~, or any other Kill ma. second- without an intensifying screen; -a me expo-ure with a -creeu and 1-inch -park fsee Fxposure Table. Any iliaphramn or cylinder will ui\'e increa-ed definition !''r one hip at a time, especially with a gas-filled tube, but it is not the ('oolidire tube except pM->ibly in a Very stollt TIIK .r-KAV 1009 Tuberculosis of the Hip. Tuberculosis of the hip is often shown by the radiograph at an earlier stage than by any other means. The head of the femur may be almost transparent and a portion be absorbed. Among the signs of tuberculosis of the hip seen in the radiograph may be an unnatural transparency of the head of the femur or of the acetabulum, due to deminerali/at ion. Absorption of the articular cartilages would be shown by an unnaturally close apposition between the bony surfaces. Malposition is readily discovered. There may be abscess-cavities or sequestra, the acetabular cavitv mav be enlarged, or the head and sometimes part of the neck of the femur may have dis- appeared. Lovett and Brown 1 report the results of radiographic study in 100 cases of suspected hip disease. They examined the collection of radio- graphs which had been taken at their hospital for a number of years and recorded the results before consulting the clinical historic.-. The radiographic diagnosis was found to agree with the clinical diagnoHs in all but o of the cases. The cause of error in 1 case was the presence of an inguinal abscess, blurring the outline of the head and neck of the femur in such a way as to cause it to be mistaken for tuberculosis. Two cases with normal radiographic appearances proved to have had hip disease: one for six months and the other for a year. All the other 1 s * cases, which gave a normal radiographic appearance, were also diag- nosed clinically. Some of these hips showed merely incidentally upon plates made for stone 1 in the bladder or other troubles. Sixty-one castes were diagnosed from the radiographs as typic hip disease, and this was confirmed by the clinical histories, both before ami subsequent to the making of the radiograph. Tin 4 radiographic appearances m an early stage, when the only symptoms are sensitiveness and muscular spasm, may not be percept- ibly different from those of a normal hip. When limitation of motion due to spasm occurred the radiographs showed evidences of bony atrophy. The earliest evidences of atrophy are diminished density and size of the bonv shadow. Bony thickening is a reparative process, and is sometimes seen at a later stage. "Reduced radiability " is the name given by Lovett and Brown to a condition in which the radiographic image is blurred or obscured; not merely faint from lack of density in the bones depicted. This condition may be due to the presence of thick serum, pus, or detritus in the joint. Similar material outside of the joint will produce the same radiographic effect, and Lovett and Brown found it deceptive in a case of inguinal abscess. Krosion or actual loss of bone substance was present in some cases, and was always shown by the radiograph. It varied from simple irregularity of the articular surface to caviiies or complete absorption. Dixplficcwcnts Resulting from Hi/> !)i*it'. These are grouped by Ashley'-' in three classes, and he states that a good radiograph affords the only means of positively distinguishing between these. In group A the proximal end of the femur rests well within the acetabulum. In group B the proximal end of the femur rests near or upon the rim of the acetabulum. In group (' the proximal end of the femur lies 1 inch or more from the acetabulum. 1070 MKDICAL KLKCTKKITY AND KONTCEN HAYS Mc< ' nrt/i/'.^ Trattx/t- trie Line for Determining Displacement at the Hip. This line may he applied to radiographs. A line through the spines of the pubic hones passes outward across the normal position of tlie hip-joints and the top of the great trochanter. Displacement may lie above or below this line. Lateral displacement is measured from a line drawn perpendicular to the transpelvic line and passing through the anterior superio" spine of the ilium. Figure 717 >ho\vs the tip of the great trochanter at the level of the top of the head of the femur, and considerably above AlcCurdy's trans- [i:c..nt!i~ uM t'racture of neck \ femur uitli non-union. (Patient re* pelvic line, wliile the head of the femur is crossed by this line. These !<'- would establish ;i fracture of the neck of the femur even ii the : >!'<; k in i he bone were not visil >le. Fracture of the Acetabulum. The examination for this injury is the *ame M- foi' ili-location of the hip. The head of the femur may be nearer :he median line than noi'tnally. and may obscure the image' of the p< hi- ;ii MM- point. The inner surface ot the pelvis here may show I in >t ru-i' >n or -phrit cnng. AIIKT .lour. is pubis. The anticathode should be at a distance of 1(1 or IS inches from the plate. A suitable exposure for an ordinary InO-pound man would be 4-inch spark, intensifying screen. KM) ma. seconds. Congenital Dislocation of the Hip. The .r-ray diagnosis is based upon a radiograph, made with the patient lying upon his back with The plate underneath and the .r-ray tube vertically over a point in the median line and 1 inch above the symphysis pubis. The anticathode should be at a distance of 2o inches from the plate for a small child or for an adult. A case had been sent to Dr. Kerley as one of infantile paralysis but. suspecting congenital dislocation of the hip. the doctor had sent the case to the author for a radiograph. On the sound side the head of the femur, still a separate epiphy.-is. as the child was only three or four years old. was seen in close contact with the acetabulum, while on the affected side there was a distance of fully ', ! inch between the ace- Tabulum and the head of the femur. The latter rested upon the ilium above the acetabulum. A glance at the rluoroscopic image did not show the dislocation, but the radiograph did so at once. The left hip was seen to be normal, with the head of the femur in contact with the acetabulum, while \\u head of the right hip was about 1 inch away from the acetabulum and rested upon the ala of the ilium. Stereoscopic Rcifliogrdphx <>J Contjcnitdl Ijixlocdtion J (hi HI/>. These picture.-, as pointed out by Ilildebrand/' are Useful as a mean- of showing the direction and extent of displacement in a sagittal or antero- po-terior plane. Ordinary radiography would not -how this di-place- ment. but only lateral or vertical displacement. A Case of Old Ununited Fracture of the Neck of the Femur.- The radiograph i Fig-. 717' was made seven months after injury, during which time the patient had been walkinu' around with a crutch. THE THIGH Fluoroscopic examination -niceeeds well in determining fracture, sarcoma, exostosis or necrosis of the femur, and in locating foreign bodies. The tube for such a fluorosropic examination should have a vacuum represented by a fi-inch resistance, the secondary current should be ;"i milliamperes. and care should be taken not to expose the patient to the .r-ray more than two or three minutes with the anticathode at a distance of 10 inches from the nearest surface. The tube may be placed further awav and several btief exposures made to cover the whole operation- removal of a foreign body or dressing a tracture. For the latter purpose it i- very convenient to have the .r-ray tube under the wooden table on which the patient lies. MKDICAI. KI.KCTKiriTY AM) KOXTiiKX HAYS In making a radiograph of the thigh cither a lateral or an antero- posterior view may he shown. For the latter, the patient lies on his hack, witli an llxll inch plate under the thigh, the antieathode di- rectly over the middle of the thigh and the middle of the plate, and '2'.\ inches from the latter. The exposure 1 for an ordinary 150-pound man would he 4-inch spark. oO ma., twelve seconds, or any other 300 ma. exposure, no intensifying screen. A radiograph made by the at St. Bartholomew's Clinic showed a bullet flattened out on the This \vas removed after twelve days by means of the rluoro- a radiograph he ing taken just after the 1 bullet had been seized forceps. Attempts at another hospital to locate the ballot by probing had failed. The reason was that the bullet had glanced along the femur to a place where it was covered by dense fascia. For a lateral view of the thigh the plate may bo applied most con- venicnilv to the inner side of the thigh, the patient lying on his side with the plate pressed between the two limbs. The author's lateral plate-holder enables the patient to lie face up with the plate held at either the outer or the inner side of the thigh. The Author's Lateral Plate-holder in Radiography of the Thigh. This is especially useful because it affords an opportunity to make a preliminary fluoroscopic examination with a view to placing the limb in the best position. For this purpose the patient may sit up on the operating table, with the affected limb resting on the horizontal le'<:-pioce. while the other limb extends vertically downward, or the patient may -land beside any ordinary table, with the sound foot ivMilm' on the ground and the affected thigh resting on the table. The tube is at the side, a\vay from the table, and the plate is held in a vertical position at the other side of the thigh. It does not matter whether this is the inside or the outside of the limb. A glance with the iluoroscope while the limb is rotated in different directions would reveal the lesion, and show the best position in which to make the radiograph. The case referred to above was one of oblique fracture of the femur without complete solution of continuity, but with a sharp projecting sliver of bone which irritated the soft tissues. There was also a fracture of the neck of the femur. A preliminary Macroscopic examination will also enable us to avoid the error in the diagnosis of a fracture into which a single 1 radiograph niiulii lead us if it chanced that the rays passed in the same plane as that in which the fragments we're bent. The hone would appear perfectly straight in this position, whereas, seen from any other direc- tion, it would show deformity. To represent the condition truly the .r-ray ,-hould .-him 1 through the thigh at a right angle to the plane in which the two fragments lie. It is better to secure this position by adjust ni' 'lit under t he guidance of the II Horoscope, and then to take one correct radiograph, than to depend even upon two radiographs an' eroi iost erior and lateral. The upper part of the femur requires the same intensity and quality of radiance and the same length of exposure 1 as the hip-joint, while the lower part of the thi-Ji affords a better picture 1 in half the time. RADIOSCOPY OF THE KNEE The knee may he .-tudied with the fluoroscope, and fracture 1 of the patell.-i Hi' liMtiv changes 1mm tubercular arthritis recognized. A lateral 107:5 view is the most useful one. Still it must he rememhered that it is a thick dense portion and that the illumination required is powerful, and consequently no prolonged examination should he made. The radiograph of the knee is usually taken in the lateral direction, and if the plate is at the inner side the internal condyle will show most 'clearly, the external condyle appearing larger and less distinct. Placing tin- plate at the outside will 0 ma., 4-inch resistance, or any other ISO ma. second ex- posure for an ordinary 150-pound man. Oxygen Injections into the Knee-joint for Radiography. Distend- ing the knee-joint with oxygen or any other gas improves the radio- graph in two ways the bony details are brought out almost as clearly as if it were a skeleton knee; the soft parts also may be differentiated to an extent impossible under ordinary conditions. Holla 1 has published such radiographs. Hoffa's method is to have the oxy- gen gas generated in a tank of hydro- gen peroxid to which tablets of potas- sium permanganate are added. An aseptic injection of oxygen was at first thought to be harmless and even bene- ficial in certain cases (Fig. 749). Danycr of Oxi/t/en Injection info Joints. Jacobsoir reports a fatal case which was attributed to nervous shock. Holzknccht has had a similar expe- rience. In Hoffa's clinic pains are taken to see that the oxygen is chemi- cally pure', and t hat t he inject ion ceases the moment t he synovial cavity is full. Schwartz considers an Ksmarch band- age a necessary precaution against the gas entering a. vein. Radiography of the Patella.- The author's screen for soft rays comes into play in making a radiograph of the patella with the plate in front, directly in contact with the patella, and the tube close behind the knee. We se- cure in 1 his way a pict lire of t he patella as it- would appear if laid bare and at from in front. Such a picture would be of value in cases of of the patella. As explained on p. 9(Ki, the screen for soft rays enables the lube to be -afely placed so near the hack of the knee that the linage o| the portions at a greater distance from the plate is so en- larged ;iiid indi-t inct as to form merely a background for the clearer linage of the patella. The author's contact diaphragm gives a still CtHlf! in-r radiograph of the patella in this position. Fracture of the Patella. According to l!a .r-rav rev LMIO-is holt s experiments 1 ' Mlbpcriosteal fracture- of the patella which would my other way. Such a fracture, without rupture of ion of the (piadriceps tendon, is usually caused by li , July <;, t'.ior,. t-'\., April 10, I '.M 17. p. L'C.O. \--nr.. vol. xlvii, NIL !.">, Oct. IM, I 1 . Hdl, ].. 1177. THE .T-HAY 1075 direct violence, and starts from within the bone and is widest at the articular surface. This type of fracture is one in which bony union may be expected without operative treatment. Barlocher 1 reports the x-ray demonstration of bony union in the patella in cases operated upon as follows: A median incision is made and the blood clots cleaned out, the tear in the capsule is closed by sutures at each side of the patella, and a row of sutures is taken, which include the periosteum and posterior- wall of the prepatellar bursa. .1 (Vf.sr of lioini Cnion .\fttr fracture of (he Patella. The patient, a distinguished surgeon, sustained a fracture of the patella from direct violence, falling and striking his knee on the stone {lavement, twelve years before a radiograph was made. The .r-ray examination was made because of pain in the knee, but the picture revealed no abnor- mality except a small area of ossification in the quadriceps extensor tendon close to its attachment to the patella. Dislocation of the Patella. This condition of lateral displacement of the patella may be shown in a lateral radiograph made with the knee flexed or in a radiograph made with the plate in front and the tube behind. In the lateral view the patella is seen overlapping the image of the condyles instead of projecting in front of them. The antero- posterior radiograph will also show the displacement better in a posi- tion of flexion. Chevrier 2 publishes radiographs of this condition. Radiography of Germ Valgum or Knock-knee. The deformity is .-hown to consist in an inward convexity, usually of the upper end of the tibia, sometimes of the lower end of the femur, and occasionally of both. The deformity is seldom, if ever, at the knee-joint. Hof'fmair finds the radiograph of value in determining the location of the curva- ture and the correct place to exert pressure by a brace. The latter should press on the abnormal curve aiid not on the knee. RADIOGRAPHY OF BOW-LEGS This shows that the deformity is due to curvature, either of the tibia or femur or both, and not to bending at the knee. Fig. ~*'l, p. 1114, shows just where pressure by a brace should be applied. The radiograph would show where to perform an osteotomy in an older child for whom the brace would not do any good. RADIOSCOPY OF THE LEG The leg could lie examined with the Huoroseope except for the danger, and fractures, tumors, and foreign bodies are the principal conditions studied. A convenient position is the patient standing with the foot resting upon a chair, the .r-ray tube being at the inner side of the leg and a little behind it. This enables one to see the tibia and fibula without overlapping. The same position can be u>ed for radiography, in which case except for the danger we would take a glance with the fhloroscope to make sure that the shadows of the two bones show separately, and then hold the plate in position at the outside and a little in front of the leg. A possible disadvantage is that the patient may not keep perfectly still. Another method consists in having the patient lie down on a table, . to. I'.to:!. \ssoc., Au'Mi-t Hi. 100t>; Jour. Am. Moth \jjsoc., >i'pt . S. 1 <)()<) p. SO 1 KM) MKD1CAL KLKCTRICITY AND ROXTGKN RAYS with tlu j le.tr resting upon the plate, and taking one picture almost directlv anteroposteriorly, but with the ler rotated inward a little, and .mother picture almost directly from the side. In the last case either side of the letr and foot may rest upon the plate. Distance 1 from anti- cathode to plate 1 23 inches, exposure six seconds with 30 ma. or any other 'HI ma. >econd e\po.-ure for an ordinary 150-pound man. No mt en ~if \ mi: -rrei-n. Tin- author's lateral plate-holder make- it verv easy to secure the corri'd pn-ition, with the tibia and fibula showing separate shadows. Th'' ktici' anil aiikh' arc supporteil on books, leaving the portion of the I'-jr to be radiographed entirely free. There are cases, however, in which t he deformity or ot her lesion is not correctly shown from this direction--/, e., with the ray pa-.-inn through the interosseous space and the plate either in front or behind, and in which the idea of securing separate shadows ot the two bone- ha.- to be abandoned. Kven then, if the plate is external and the expo-ure rather strong, the outline ot the filmla mav l>e seen on the background of the tibia. The n ppe rand lower parts , if t he filmla are easily .-how n in 1 his wav. A Case of Simple Fracture of Tibia and Fibula United With Slight Malposition. The radiograph i Fi()) was taken as proof of the nature of the injury in a suit agam-l the company responsible tor the accident, and not on account of any complaint airain.-t the surgeon who treated the case. A radiograph trom another direction showed marked anirular ' left irmity. A Case of Simple Fracture of Tibia and Fibula After Union in Mal- position. The fracture had been a comminuted one. and the surgeon who dre.--ed the injury had made an incision and removed trau'ineni- ot bone and placed the end- in u'ood apposition. The bones must have Clipped at some -ubseqiient dre ini:. for the radiograph Kiu. 7">1 . taken -i\ month- later, .-hows marked lateral displacement ot the (Yai:- KITS MEDICAL KLKCTKHITY AND RONTGEN HAYS ments df both hones and sonic overriding and shortening. The picture shows what can he done with a high-frequency outfit. Pott's Fracture. This fracture of the fibula 1 or 2 inches above its lower ext remit v is frequently accompanied by a fracture of the internal malleolus of the tibia and sometimes by laceration of the internal lateral deformity is produced by a bending directly to the ic correct radiograph is one made in an anteroposterior tube should lie in front and 1 inch above the level of The foot is fully extended, so as to avoid contact The plate is placed behind the ankle and heel. The as it means that the plate is 1 inch further from the ilate were held close to the back of the ankle above ligament. Tin outer side and direction. Tin the ankle-joint. with the tube, heel is in the wa\ fibula than if t he the heel. The latter position would enable us to show a fracture a couple of inches above the malleohis, but not the lowest part of the tibia, which it is also import ant to show. The author's lateral plate-holder is of great service; here. The patient lies on the operating table, with the foot extended and its inner -urface n-stinir on a book. The vertical part of the lateral plate-holder . 7.VJ hold- the plate behind the foot, and the tube is placed in uid at a di-tance of '2'.'> inches from the ant icat hode to the plate. A pn-liminary fluoro-copic examination is facilitated bv the use of this I i^. ~ '>''> . bul is extremely daimerou- to the operator. ; -park, Mi) ma., and no intensifying screen t he exposure for a l.)0-pound man would be seven and a half seconds or any other 2l2"> xpo-urc unless the ankle were in plaster of 1'aris. In the. latter ca-e an intcn-ifving -'Teen would be used. TIIK .C-RAY 107 ( J >. Fluoroscopv of the ankle preliminary to radiography with the lateral holder. An extremely dangerous practice. 1 : 10SO MKIMCAL Kl.F.i TKKITY AM) KONTCKN HAY FLUOROSCOPY AND RADIOGRAPHY OF THE FOOT Fluoroscopy inches from !'<>' the ankle-joint and the articulation between the as- I tin ''- faicis the foot is turned .-o that the inner margin of th'- snle rest upon the plate, and a compression cylinder LI. 7-V> . |-'<>r diairno-i- of flat-foot the inner side of the foot and aii fe-i upon the plate. m a- nearly a natural position as possi- ble : ' tube vertically over the prominent ba.-e of the fifth n i '.!' i ' - Hallux Valgus. I i---. 7">7 7f'.D illu-trate a case of hallux \'al^u- operate.l . tin author at M. l>artholoinew'~ ( 'linic and reported THK .r-HAY 10SL in the New York Medical Journal. The patient, a young man of twenty- three, was almost crippled by the exaggerated deformity of both feet, the radiograph showing thai the great toe was at a right angle to the corresponding metatarsal bone. The operation consisted in cutting out a wedge-shaped section of the head of the metatarsal bone. This enabled both bones to be brought into a correct line. The kodak picture -hows the deformity, which looks like a swelling or bunion on the great toe- joint, but the .r-ray at once revealed the bony deformity. As a result of the operation he is now able to be on his feet eighteen hours a day smashing baggage at the (Irand Central Station. Various Anomalies in the Tarsus.- These have been studied in anatomic specimens and in radiographs from living subjects.' 1082 MKIMCAL ELECTRICITY AM) HONTdKN HAYS The .r-ray is valuable in cases of deformity of the foot as a guide to operative treatment or to the application of the proper means of support. A case of tali pcx c(jitinu.s was radiographed with the side of the foot resting upon a plate placed horizontally on the table upon which the (.1,11,1 l a y. The tube was vertically over the opposite side of the foot. Mv rad'ioL r r:iph -howrd that the lonji bones of the foot were almost in a straight line with those of the ler. THK J-KAY 1083 I I I'lir. 7.~>S. Hallux valf^us after operation on one foot. iu. 7 .V.I. Hallux vakus after operation on hotll feet A case was examined for possible fracture of some hone in the tarsus. The foot was deformed in consequence of infantile paralysis producing 10S4 MEDICAL ELECTRICITY AM) RONTGEN KAYS taji})<* ilde under THK J-KAY 1085 (he heel and tarsus and under the outer side of the metatarsus, while the inner side ot the metatarsus was allowed to come down into contact with the sole of the shoe. The radiograph showed that the inner meta- tarsals were strongly flexed, while the outer ones were not, and the os calcis did not nearly reach the ground. Benoist 's radiochroniometer was laid upon one corner of the plate to register the decree of penetration of the ,r-rav. This proved to lie Xo. S Benoist and seemed to he excellent . Fracture of the Tarsal Bones.- This condition is best shown in a radiograph taken with the plate against the inner side of the foot, which is to l;e inverted, with the tube at the outer side. The use of the author's lateral plate-holder en- ables one to make a preliminary fluoroscopic examination and place the tube in such a position that the ray will shine through between the bones and show their images sepa- rately. The toes are pointed upward and the heel should rest on a book. The photographic plate is placed vertically beside the foot. Fracture of the Metatarsal Bones. This injury often presents the same difficulty as a similar injury in the hand; due to the fact that the displacement is apt to be in a dorsoplantar plane, the one usually traversed bv the .r-rav. jz. 7t ruck her loot violently airain.M the door-post. She was in her stockinged feet and all 1 he force was received by the little toe. Congenital Absence of Last Phalanx of Great Toe.- Figure 7(iM illu-t rates t his condit ion. 1080 MEDICAL KLKCTRICITY AND RONTGEN RAYS THE UPPER EXTREMITY In a small or medium-sized person a fluoroscopic examination suc- ceeds fairly well about the shoulder, l-'ractures of the humerus and dislocations at the shoulder-joint show very well. Fractures of the, scapula and clavicle arc more difficult with the fluoroscope, and so are the different diseases of the shoulder-joint. The patient should be; sitting or standing, the tube bein^ in front and near the median line, with its anticathode at the level of the outer end of the clavicle, and about 10 inches from the nearest surface. The fluoroscope is held behind and somewhat to the side of the shoulder. Fluoroscopy of the shaft of the humerus presents no difficulties except in very lar^e persons, and in one of the author's cases an oblique fracture of the humerus was dressed under direct observation by the x-ray . In this case the contraction of the different muscles caused such an overriding of the oblique surfaces that a xaminat ion, bin even here radiography is the method for exact diaii- no-iX Yerv nianv times a needle mav be searched for in vain with the loroscope and be revealed bv a radiograph, having been concealed by use bones of the CM rpiis. Fven one o! the less pertect radiographs, made directly on bromid paper and developed without any dark room, - ;cceed in ;i case in whicli the fluoroscope falls. I !: radiographing the si i milder the pat ient hail bet ter lie on his back', With ' ' under the affected shoulder, and the outer edi^e of the !'!;:> rai-e ; -oiin \\ hat from the table, so as to lie at a riu'ht angle to the direct . The tube is placed so that its anticathode IS " river a point '2 inches internally to the acromioclavicular i '_':; inches from the plate. Jf both shoulders are taken THE .r-HAY 1087 for comparison it is host to take them at the same time. The tube, is over the median line, at a point corresponding to the level of the acromio- clavicular articulations, and a single large plate may be used, or, prefer- ably, two 10 '' 1 '2-inch plates, so that each may be tipped somewhat SO as to direct Iv face tin: tube. ' Such a picture shows the clavicle very well. but. of course, not so well as a radiograph taken with the plate in front of the -houlder and t he t u be behind, and at about the level of the acromii iclavicular art icula- tion, and M inches from the median line, and 2o inches from the plate. The length of exposure for a shoulder radiograph will vary with the si/e of the patient: for a InO-pound man. with the tube in front, near the median line. 1-inch spark, oO ma. for twelve seconds or 10 ma. for thirtv- loss MKDICAL KLK< TUHITY AM) HONTo'KX HAY: six second- or any other otiO ma. second exposure, without intensifying screen. The same exposure with the tube behind, 10 inches from the me- dian line. But with the tube behind close to the median line, o-inch spark, 3t>0 ma. second.- and intensifying screen. The last exposure gives a view of the upper extremity of the humerus at a right angle to the first view and is a device of the author's indispensable in case of fracture of the neck of the humerus. If an anteroposterior view of the humerus is required the patient had better lie upon his back with the arm somewhat abducted, the plate need not be larger than S x 10 inches, the point of chief interest being at the center of the plate, and the anticathode over the same point and 23 inches from the plate. Resistance 4 inches, exposure four seconds with >n IIKI. or ;my other 120 ma. second expo>ure without an intensifying sen-en. The above figures are fora l~)0-pound man i Fig. "fill. To radiograph the humeru.- from the >ide it i- not necessary that the patient -hould lie down: the plate i- held between the arm and the side <'t the body, the tube beinu ;it the oiit-ide of the ;inn; otherwise the pl'oce i- the smie a- for an a lit eropo-t erior view. The elbow i- radiographed atiteroposteriorly in a position of exten- -loti. with the dorsiim re-tin": upon the plate, which i- laid upon a table alon-j-ide of which the patient -it- Kin'-. ~iil and 7o.~i . or a lateral view l>e taken wit h t he elbow semi flexed and it s inner -urface re.-t ini: upon 'he plate I- in-. 7f,r, . There i- one po.-itioii ill which the head of the ra- diu- and t he ot her bone- which take part in the elbow-joint ca n be >ho\vn separately 1-iii. 7*17 . The (-Ibow and forearm should rest upon a table, lietore which the patient i- -eated. The hand i.- pronated and rests on THK J"-HAY 1089 the table. The elbow is partly flexed and the elbow as a whole is ro- tated as far as possible. A thin soft pad is placed over the elbow and the Albers Schonberg compression cylinder is applied to immobilize the elbow in this somewhat strained position. The x-ray tube is somewhat toward the outer side. In either case a 10 \ 12-inch plate is used, and care is taken to place the anticathode directly over the space between the articular surfaces of the humerus and radius. Distance 23 inches, exposure the same as for the arm. For the forearm the patient sits at a table with the supinated fore- arm resting on the plate. An 8 x 10-inch plate will show the whole length of both radius and ulna (Fiji. 7(58). The tube should be over t'Tinl the center of the plate, and the distance from the anticathode to the plate 23 inches. Exposure about the same as for the arm and elbow. I'or the wrist the condition- are the same as for the forearm, the hand generally being fiat upon the table in a position of pronation Sometimes, however, the displacement of the fragments fracture is better shown if the radial side of the wrist is plate and the ulnar side away from it. This position re- the plate shall be held vertically and the wrist supported II this cannot be conveniently done, almost a; good a lateral view may be obtained by laying t he plate upon a table and rest in u.' the radial border of the hand and wrist upon it. The portion which i- KM)!) MKD1CAL KLKCTKiriTY AM) HoNTCKN HAYS nearer I he plait- ^ives the clearer linage, and this is the reason the radial side >hould In- next to 1 he plale in taking a lateral view of a Colics' t'ract tire. A more recent device of the author's employs a cardboard box tran-parent to the .r-ray. The patient's wrist rests upon this not ab- i . ' \ n il r-llxnv .-md furc:tnn. Arm arid fnn -MTU i n- 1 in i; Hipinc upon th(? plait 1 . -olutely prone, but with the radial -ide rai-ed a little. The ./'-ray tube i- at the uinar -ide ;it the level of the \vri-t and the plate is vertical, with it- edu f e re-tirm' on the table, held clo external to thai of the ulnar and five from it. A third radiograph dunvs hoth wrists with their ulnar hord(Ms resting upon tin- plate, the MKDICAL KLK< TKKITY AM) KO.NTCK.N KAY. 71 Author'.- second position for radiography ol Colics' fracture: showing dor.-a border of radius. ML', r i _'. .\ ..! - t liirM [id it idii for r:ir]idL r r:i|itiy d) ( 'dllc.- frari urc : -crniprcii THK .r-KAY hands being somewhat inverted so that the palmar margin of the radius i< free from the shadow of the ulna. But in this last picture the dorsurn of the radius is obscured by the ulna, and the characteristic displace- ment if slight is difficult to make out. To secure a clear image of the radius when thus held away from tin- plate the anticathode should be 23 inches from the plate. The patient -hould hold his breath during the exposure. Radiographs of the carpus, metacarpus, and phalange's are com- monly taken with the palm of the hand flat upon the plate. If the whole hand is taken, the tube should be far enough away to shine between the articular surfaces of the different joints. Twenty-three inches from 1094 MKDK AI. KLKCrHH'lTY AM) UONTCEN HAYS the antioathode to the plate is the best. At this distance 1 the exposure would l>e seven and a half seconds with ',]() ma., or any other 22f> ma. second exposure for a 150-pound man, resistance' 4 inches. A lateral view of individual finders is often useful in the diagnosis of fractures or dislocations and in locating foreign bodies. A bromid-paper print, made directly with two or three times this exposure, is especially useful in .r-ray examination of the hand. It can be developed in the operating room by simply darkening the room moderately, and the whole process takes less than five minutes. The imam 1 is better than that visible with the fluoroscope, and can be studied for any length of time, thus avoiding the dangers attendant upon a prolonged fluoroscopic examination. Duplitized films, with a short ex- posure, are better if a dark room is available for immediate 1 development. The Albers Schonberg Compression Cylinder in Radiography of the Upper Extremity. As indicated in the case of radiography ul the elbow, the compression cylinder is useful for immobilizing the part to be radiographed hand, wrist, forearm, elbow, arm. or shoul- der. It is useful for improving the definition in radiographs of the ,-houlder or elbow, but elsewhere in the upper extremity all the neces- sarv detail mav be obtained without it. Other Convenient Methods of Immobilization of the Upper Extremity. Sand-bags may be laid along both sides of the limb. 'Ill'' bill's in winch .") oi' 10 pounds of salt arc sold serve very well for tlii- purpose. The salt itself is all right at first, but it becomes hard and inflexible after exposure to a damp atmosphere. Sand alwavs remains soft, and adapts itself to any surface which it rests against. A device suggested bv Johnston' consists of a long cloth bag at each end of which is 10 pounds of shot . Tin 1 bag is laid across t he limb, and the hc;ivv ends hang over the sides of the table. The author and some other operators use a special but extremely j Am. Quarterly of lioiilncin.ln^y. I!u7. THE X-RAY 1095 simple bandage for immobilization. A wide bandage is split for a tew inches near the middle, one cud is fastened fit one side of the table; the bandage is carried over the limb, completely around it, and then through the opening in the bandage where it crosses orer. not n inter the litnh, and thence to the opposite side of the table where it is drawn tight and fastened. This has the advantage of preventing rotation and lateral displacement of the limb, as well as preventing it from being- raised from the table. Congenital Lesions of the Upper Extremity Revealed by the .r-Ray. Joaehimsthal 1 gives thirty-three excellent radiographs illus- trating these different conditions. ('<)////( nitul ilixlix-iitioti of the shoulder is quite a rare condition, only one-twentieth as frequent as congenital dislocation of the hip. Patient now seven yeui'd o A case reported by Porter." and also seen by Hidlon, shows that the radiographic appearance is not as striking as might be expected. The image of the affected shoulder should be compared with that of the sound shoulder made in the same position, or. in case of both shoulders being affected, the shoulder of a normal child of the same age should be radiographed for comparison. Congenital Epiphyseal Injury at the Upper Extremity of the Hu- merus. A case under the author's rare illustrates the radiographic diagnosis of congenital injuries at the shoulder i Figs. 77(1 and 777). The pal lent, a boy of seven, was said to have been taken by the left arm and thrown across the room by the doctor when he was born. lie was never able to move his left arm afterward. \Yhen examined there was tound to be no movement at the shoulder-joint. The arm could be moved only to the extent of movement of the scapula; it could (It'll. (1. Knnt.srcn.. l'.t(M). Supplement \<>. '_'. 1. Journal. August Iv 1 '.<><). 10% MKDH AL KLKCTHH'ITY AND KOXTOK.N HAYS not he placed vertically at the side of the head, and the hand could not he put hehind the hoy's hack. Muscular power was ^ood and the hoy could cliinh a tree. The left shoulder looked as if dislocated. There was the sharp tip of the acroinion process and helow this a hol- low. The head of the hunierus. however, could not he felt either outside or inside the solenoid fossa. A radiograph was made of the two shoulders, with the tuhe in the median line in front and a plate hehind each shoulder. The head of the hunierus on the sound side looked as larii'e as a hen's extra index-fingers. Somewhat different is the 1 case' shown in Fig. 77 ( .) (radiograph by Dr. McKe-nzie at the Yanderbilt ('linic). He'iv there we're 1 apparently tin) Ihuntli*. One of these 1 sprang as a sort of e'\oste>sis from the proxi- mal phalanx of the thumb and had a single, distal phalanx of its envn. This was fixed in a position of flexion. II MKIUi AI. KLKt TKHITY AND RONTGEN KAYS Various Anomalies in the Carpus.- These have been studied from anatomic specimens and from radiographs of living subjects. 1 Radioscopy in Fractures of the Upper Extremity.- The treatment of fractures of the clavicle and scapula is not, as much aided by the .r-ray as that ot tract ures of the other bones of the upper extremity. \Jrnctnrt oj tin u/t/xr r.r//7 /////// of tin hintuni* usually shows little lateral displacement. The diagnosis is based upon the presence of a -harp line across the bone. The portion above the line is broader than the portion below and its square corners project on each side. I' /'net u/'t oj tin i//'(iit(i' tubcroxiti/ of tin h nt/n /'//> should, according to Meszytka.- be looked tor in all doubtful cases of injury simulating Hibluxation of the shoulder. The radiograph should lie made with the plate und'T the shoulder, which is slightly raised by a cushion. The a I'm should be adducted and minted outward. It should bo fixed in position, and the exposure should, it possible, be so short as to en- the patient to hold his breath during its continuance. A case of supposed dislocation of the shoulder was subsequently shown bv the ,/'-rav to be a frnrtnrt' of lln 1 xiii'i/iriil in r/c of thr hiunrrHS with displacement outward of the upper fragment and inner disphice- lower traii'inent. The case had been treated as one of dis- location; ih^rc had been union in malposition, and the case formed r.. .IllU L's, 1 ',t(lti. TIIK .C-HAY 1099 the basis of a law-suit against the physician, in England, who had taken care of it,. 1 (See page 10S7 for technicj Fracture* of the *hajt of tin 1 ku merits are readily inspected by the x-ray and the possible overriding and bending may be avoided by up- plying the dressing under .r-ray guidance. Fracture* of t lie loicer extremity of the humeru* present several different forms, and the fluoroscopic image will be found of the greatest possible; assistance in getting the fragments into position. This may make the difference between a permanent lv impaired elbow-joint and one which is perfectly useful. Keen 2 reports a case of operation for nun-union after fracture of the humerus. The .r-ray showed the presence of the aluminum-bronze wire one year after the operation, but two years later tin; wire; had entirely disappeared. A fracture of the olecrnnon )>rocc** of the ulna, will show very well in a lateral radiograph or in an anteroposterior radiograph with the plate behind. There is, in the anteroposterior picture, a perfectly normal appearance of a transverse line across the olecranon process, at the level of the superior articular surface 1 of the radius. This must, not be mistaken for a fracture. The latter produces wide separation, not a mere transverse line. Fracture* of the *Ji<(fi of the radiu*. or ulna, or both, are seen in the fluoroscopic or radiographic image, and overlapping or lateral displace- ment on bending may be discovered even after the splints have been applied. One of the author's patients was a four-months'-old baby, with bones only the size of pipe-stems, and such a fat, chubby forearm that the bones could not be felt. One of the author's radiographs showed a "green-*tick" fracture of the radiu* in a child ten years of age which had not been suspected by the parents until the development of a lump due to the formation of callus at the seat of injury. The line of fracture was visible and also the callus, but there was no bending or displacement. Nat rig 3 also reports 2 cases of long-standing tenderness in the wrist which the .r-ray showed to be due to old unutnted fracture* of different bones in the carpus. Colli N' fracture of the lower extremity of the radius is one in which some little study is required to make the .r-ray of real service. Two radiographs, are required for the diagnosis of this condition. One is made with the hand and forearm placed fiat upon the plate arid the tube over the back of the wrist at the seat of fracture. A fracture >hows a transverse line, which represents the broken surface of the lower fragment. Square corners of this project on either side, because thi- fragment is wider than the portion of the upper fragment which it overlaps. No lateral displacement is usually seen in a dorsopalmar radiograph. A second picture is made in a lateral direction, which shows the line of fracture and the dorsal displacement of the lower fragment. The edge of this fragment shows especially clearly upon the back of the wrist. This lateral radiograph is made 1 with the radial side of the . til. MEDICAL ELECTRICITY AND RONTGEN RAYS wrist on the plate and the ulnar side a\vay from it, but the wrist is turned a little so that the ray. passing from the tube in a vertical line through the radius. goes through the open air. not through the ulna or the soft parts of the wrist. The proper posit ion is very simply obtained by having the patient crouch down at the side of the table on which the plate is laid and resting the radial border of his hand on the plate. This can be arranged in much less time than any other position, bat- is rather crumped, and in the case of a recent injurv would be found painful. A more comfortable position for the patient is obtained by the use of the author's lateral plate-holder. The forearm and hand are supported in a natural position of semipronaiion. the plate is held vertically tit the radial side of the wrist, and the tube is at the ulnar side. A preliminary glance with the fluoroscope will venfv the correctness of the position. A lateral radiograph of the wrist .-hows the profile of the dorsuiu <>f the radius, but the other structures of the wrist form a confused mass from the overlapping of their shadows on the plate. Fractures of the carpal bones are correctly radiographed with the palm of the hand resting upon the plate and the tube vertically over the bark of the carpus. An old un united fracture <>f the xenjihoid Innic. which had given symp- toms .-uppo.-ed for more than two years to indicate rheumatism, sprain, tenosynovitis, or tuberculous periostitis, was discovered by Hammond 1 by means of a radiograph. The fragments of the scaphoid bone were freed from intervening fibrous tissue and united by silver wire with a perfect result . FrnrturcH of tin ///< /amr/xil honex are about the only ones of the upper extremity which are apt to escape detection by the fluoroscope, and they sometimes require careful study to determine by means of radiog- liy. The difficulty is due to the fact that there is seldom any lateral displacement. The bone is bent toward the palm of the hand and thi- llexion does not show in a dorsopalmar view, and the line of fracture is also apt to be indistinct in this view. Twisting the hand so that the different metacarpal bones may be viewed from tin; side enable- one to make certain of the diagnosis. A lateral radiograph of the first, second, or fifth metacarpal bone is easily obtained by placing i he radial or the ulnar border of the hand in con t act with the plate, while 'lie other border of the hand is away from the plate at an angle of about 4.~> deirrees. The x-ray from the tube passes obliquely over the back of t tie hand. The metacarpal bone at the border of the hand which is in 'ontacl with the plate shows verv distinctly, while the other shows less .-learly. A Special Device of the Author's for Lateral Radiography of all the Metacarpal Bones.- The object is to have the plate practically in con- ;iH with all the metacarpal bones and thus to secure clear images of all of them. The hand i.- placed palm down on the plate and the tube i- placed over the back of the hand, but so far to one side that the average alible of the rays pa.ssing through the metacarpal bones is }."> deon-i--. The picture 'Fig. 7r radiograph- ing the- phalanges resistance 4 inches. There is very little tissue 1 to be penetrated, and, of course, the lower degrees of vacuum proeluce radiographs with much greater contrast. Here, as elsewhere, the more intenx 1 the raeliance, the shorter will be 1 the exposure, and a nor- mal exposure for a 150-pound man at 23 inches without an intensify- ing screen would be' o() ma. for three seconds or any other ( .M) ma. second exposure 1 . Dislocation of the Shoulder. The examination is made with the' tube in front of the shoulder and towarel the' meelian line. The plate* or the 1 fluorescent screen is placeel behind the' shoulder and its outer eelge is further forward than the' other. The- head of the humcrus is seen an inch or two from its normal position, where 1 it should fill out the space extending outward from the' glenoid cavity and under the acromion process. Kven in a very stout person it is possible to show this condition, though the plate is necessarily thinner and the picture fainter than in a slight person. Dislocation of the Elbow. A backward dislocation is shown in a radiograph made with the inner surface of the elbenv resting on the plate and the lube over the outer surface. A lateral dislocation is shown in a radiograph made with the' back of the 1 elbenv resting upon the plate and with the tube over the' front. It may not be practicable to straighten the elbow on account of pain. In this case', the' point of the elbow mav rest on the plate, and the arm and forearm are 1 at about tin 1 same angle from the plate and the tube is in the angle between them, at a di>1ance of 12 inches from the 1 anlicathode to the plate. The radiographic -hadows of the bones are almost the same as if the elbow were straight, e-xcept thai while the image is <|uite clear near the e-lbow-joinl the shadows of the upper part of the arm and the 1 lower part of the forearm are enlarged and vague. Fracture-dislocation of the elbow is shown in Fig. 781. Subluxations of the head of the radius occur more commonly than \\ a.- former! v supposed. A small child is walking be-ide its mother, who is holding one hand, the child stumbles, and the mother gives a jerk, whie-h lifts the child to its feet and injure- its arm. There rtain amount of pain and swelling ami the hand cannot be 1 su- 1 he .r-ray examination is not an easv one. The -. and will not hold hi- arm .-till while the radio- in o.-t practicable method is to have a celluloid I inches wide, wrapped in light-proof envelopes od -plint or a strip of heavy cardboard. The fn ml of tli THE .r-HAY bandage. The ai'in may then be held up before the x-ray iul>e, \vliich is behind the elbow and a little to its radial -ide. Dislocation of the Joints in and About the Hand. These require the same technic as fractures of the same region. Details of the Soft Parts in a Radiograph of the Hand. The best radiograph of the hand is taken with a low decree of vacuum, so as to have threat selective absorption, and with a high decreed intensity, so as to impress every detail upon the plate, and a sufficient length of exposure so as not to require abnormally long development. The lechnic already described is as good a general guide as can be suggested, but experiment at inn with one's own apparatus will perfect the results. The outline of the llesh shows as well as that of the bones, and every difference in the thickness of the soft tissues is brought out. Certain differences in densit v are revealed : t he nails, for instance, show perfectly well, and faint outlines of some of the muscles and tendons are visible. As man\' as eight distinct shades of color may be made out on a good plate. The arteries do not usually show. If they show distinctly it is an evidence of at heroma. 104 MEDICAL ELECTRICITY AND RONTGEN RAYS Radiographs Showing the Cutaneous Markings. These are made by a sort of trick. Powdered bismuth subnitrate is rubbed into all the creates of the palmar surface of the hand and fingers for the picture made with the palmar surface on the plate, and into the grooves around the finger-nails ami all the creases on the back of the hand and fingers f the lower oxtromitv of the humerus with backward displacement I'lastrr-of'-Paris splints front and hack i<>r the dorsal picture. Bismuth is so opaque to the .r-ray that it casts a .-hadow showing all the natural markings of the -kin. Functionally Good Results After Fractures. Radiographic Appearances. Tonw 1 suinman/es the tacts. Before the discovery nf the .r-rav we believed that the anatomic results were much better than iln 1 radiograph now shows them to be. The latter has established an ideal as to the result which it is often impossible to attain and which ii! ino.-t cases would have no advantage for the patient. The practical ideal is to secure a good functional result without deformity, recogniz- able by the unaided senses. The r-ray shows that very few oblique fractures of the leg or arm are treated without shortening and other deformities. One x-ray picture ma}' exaggerate the deformity just a- another may '-onceal it. It is unjustly exacting as to the results of t r;n't nre- in lega 1 cases. Radiographic Appearance of Callus After Fractures. Recent callus i- not opaque to the .r-ray. but permanent callus, or that which has changed into bone, is similar to natural bone in opacity. 1 Jour. Am. Mcil. Assor.. Jiiix- 2. I'.MHI. THK X-HAY 110.1 RADIOSCOPY IN DISEASES OF THE BONES AND JOINTS TABLK OK DISKASK.S OK TIIK BONKS AND JOINTS IN WHICH ./-KAY KXAMI. NATIONS. AUK. i >K SKI: \ ICK ' xti-i/i*. Spina ventnsa. sfi/'t/* Dfjiinininx. -A fieri s i>ntli None and perin.-ieinn. x/i'i>ti/<-i/tix. Aliscess, ni ((( is, se<|iie>t ra. I Keijt'iicrafion of Hunt Ajhr ()/>i-ru/inntixi. Acute and chronic. i Gout. )r/><>nitx iihni/t joint*. including urate of soda or lime salts. , is based upon the history and other similar considerations. Benign cysts occur in bone, and are seen in the radiograph as large, sharply defined, rounded areas of translucency. Such a cavity was ' A found 1 iv 1 he a ut dor in a case <,f tic douloureux. It was very small and i:i : port ion of t he lower \-,\\- t'ro/n which t he t eet h h,-id long ,-ince been extracted. Kxo-to-es -how as projection-, sometime- ot normal bony ti--ue, ninetime- of r;ire|ied or of unnaturally den.-e bony tissue, depend- in', ipi in t he c;iti-'' of the ' >>idi' loll. ACROMEGALY THE X-HAY 1107 enlargement of the hones, both in length and thickness. This was especially marked in the great toe. BONY CHANGES SHOWN BY RADIOGRAPHS OF CASTRATED ANIMALS L. Hichon and P. Jeandelize 1 find that rabbits, which are castrated when young, show certain bony changes when adult. Their radiographs show elongation of the long hones and increase of weight; these changes being most marked in the posterior extremities. OSTEOMYELITIS AND NECROSIS These may he regarded for the purpose of .r-ray diagnosis as different stages of the same disease the stage of inflammat ion, and the subsequent stage during which nature attempts to remove the dead bone produced. L10S MEDICAL ELECTRICITY AND KONTGEN RAYS Tin- gradual formation of an involucruni, or enveloping sheath of newly-formed hone around the dead portion, may he observed in a series of radiographs. The hone eventually looks twice the natural size, and may not present the usual appearance of canccllous tissue or mveloid canal. ACUTE OR CHRONIC PERIOSTITIS These eases show a somewhat irregular projection beyond the outline of the hone, which is usuallv distinctly \-isihle. The density of the perio>tea] .-welling is at first only slightly irreater Than that of the overlyin.if flesh, hut as the case becomes chronic more and more irreg- ular bony tissue or 10 decrees. \ olun- tary movement of the arm was almost entirely accomplished by motion of the scapula, and. of course, was very limited. There was marked atro- phy of the deltoid muscle and the muscles of the arm. The patient could not raise her rkdit hand to shake hands or to carry food to her mouth. She made all such motions bv liftinir the n'uht forearm with the left hand. An .r-ray examination was made, which showed a perfectly normal left shoulder and (Fig. 786 made in the same position) a most unnatural condition of the ri^ht shoulder. The disease seemed to affect chiefly the head of the Innnerus. which was flattened on top and had lo>t the natural uniform convexity of its art icular surface. It was evident that the material fora normal ball-and-socket joint \va- absent, and that forcible breaking up of the articulation would have produced serious injury. 1110 MEDICAL ELECTRICITY AND RONTGEN RAYS Treatment l>y high-frequency currents applied from vacuum elec- trodes had a somewhat restorative effect upon the muscles but left the joint unimproved. A long course of treatment has been conducted by Dr. Shaffer, who considers the case one of tuberculosis. A brace has been used to prevent motion at the shoulder-joint and support the weight of the arm and at the same time permit of the use of the limb. There has been great improvement in muscular power. A corroborative fact in favor of tuberculosis is the development of a case of ] lulmonary t ui >erculosis in one of the patient's brothers. The case is one which has pu/zled .some of the best surgeons and orthopedists in this country and Kurope, and the varying diagnoses of rheumatism, osteomyelitis, and tuberculosis have all been regarded as verified by the appearance found in the radiograph. It shows the importance of an .r-ray examination at the earliest po-v-ible moment in every case of joint disease. If this case had been radiographed at different periods from its earliest manifestation the diagnosis might have been certain and much useless suffering from unavailing manipulation avoided. SYPHILIS OF THE BONES This disease presents itself for x-ray diagnosis in two general groups-. 1. Svphilhic gumma; 2, syphilitic inflammation. Gumma of Bone. Wherever this specific neoplasm occurs the radio- graph .-hows a combination of a destructive and a proliferating process. Some part of the bone is usually rarefied, another part may be denser than normal, and there is often an increase in the size of the por- tion < it bone affect ed. The Periosteal Type of Gumma. A considerable number of radiographs have been published of this variety of the disease. 1 The typic Rontgen picture of syphilitic gumma of bone shows the shaft of the tibia, for example, presenting at one side a perfectly normal outline and the normal thickness of corticalis in the normal relation to the rnedullarv canal, while on the other side the corticalis is thinned bv irregular patches of rarefaction and its uniform outline can no longer be traced, the periosteum is intact over a swelling, which shows more or le.-s ossificai ion. At the extreme margins it is quite easy to see that the swelling is a periostea! one. because there the bony contour is preserved with the jess dense shadow of the periosteum gradually springing away from it. A commencing ^umma. with a slight periostea! swelling, hardly at all ossified, and with verv little rarefaction of the corticalis. might not be distinguishable bv the r-ray alone irom traumatic periostitis. The Myeloid and the Cancellous Types of Bone Gumma. These b'"jin on the inner surface of the corticalis of the shaft or in the cancel- lou- tissue of the epiphysis. Neither of these present marked charac- teristic- bv which t hey may always be easily distinguished by the x-ray alone from tuberculosis, sarcoma, and other diseases. i Koliler, I or1 a. 'I. f!-h. (I. Kocnt., vn], x, \r>. '1. 7.",, I'lOC,; Knoclicncrkrank- unir'-ii im I;-" ;>: L" nMH". .1. I 1 '. I'cnrniann : Ihilni, Kontircn Congress, l!i()<>: Halm iui'1 Df-yckf. Knoriirii--y|iliilH ini KocnttrcnbiMc, l!(i: Hitter, Wicn. klin. Woch., J'JUT, No. i'>, p. ic,j; Ware, . XimaN of Surgery. Anirii-t, 1!K)7. p. I'.i'.t. THE X-RAY 111 I"JL r . 7^7.- (iunniia of the soft parts not affecting the inctatarsal hone. (Radiograph by Dr. B. P. Riley, St. Bartholomew's Clinic.) L'. "ss. Gumma of the radius and of tin- first nictatarsul none. (Radiofrranh bv Mr. Brush. Mctronolitan Hosi)ital. ' Th<\v arc both myelogonous, arising in 1)1^ marrow either of the nivel'me canal or the' marrow of the spaces in the eancellous tissue of t he epiphysis. 1112 MKO1CAL KLK( TKU1TY AND HONTliKX HAY Phey are apt to exist in the same bone l>y extension from one part to another. Fiti'im- 7S8 i Mr. Brush) shows this condition. Spina Ventosa Syphilitica. This disease affords a good example of a myelogenous .minima of bone. One of these fingers presents a fusi- S; liilitif nrthriti- of thr kneo. ("Rauinjrrnjih }iy Mr. Hrush, Metropolitan form -weUini: ;ti)out a joint without much redness or pain and with a low proirress. It feels bony, but as if the bony wall was as thin as ii ctrir-shell. The radiograph shows marked rarefaction of the epiphy- - and the iieiti'hborin.iz part of the shaft ot the affected bone. The llous tissue of the epipliysis ma\' be largely absorbed and the bone ken. Then- is a periostea! swelling, which ]i'esents a varying amoui ' of o-sification in different cases. formation of new bone is about the only feature which dlS- tin'j",' hi'- -uch a r-asc radioirraphicallv fi'om tuberculosis. The . ithor ha- seen cases of spma \'enlo.~a m which the radio- i:ra])hic a ;tuce did not enable us to differentiate letween syphilis and -imple o.-tenniyelitis. The hi.- lory in one ca>e pointed to hereditary r-yjihilis. THK Z-KAY A case of gumma of theepiphysisof the radius is reported by Koehler, which the racliographic appearance alone would not have enabled one to different iatc from sarcoma. His description of the radiograph is as follows: The entire bony structure of the proximal half of the radius is verv much altered. The shaft is somewhat rarefied from the middle to the t uberositv and the thickness of the corlicalis is reduced. The sponu'v tissue of the epiphysis has almost completely disappeared. The compact tissue of the epiphysis is irregular in outline and reduced to the t hick ness of paper and has protrusions at different places. The articular surface of the head of the radius is practically normal. The only differ- ence between this and the radiographic appearance of a sarcoma is that, in the latter case, there is usually a sharply defined dividing line be- tween the diseased and the sound bony tissue. SYPHILITIC INFLAMMATION OF THE BONES NON-GUMMATOUS) A patient suffering from syphilis is peculiarly liable to every form of acute or chronic bony lesion which may be covered by the broad term Inflammation. Some of these are quite similar to simple inflammatory pro- cesses of the same type, but very often t he .r-ray will show a decided difference; A radiograph of a patient at St. Bartholomew's Clinic, with a somewhat tender fusiform swelling of the tibia, showed that this was a pure hyperpla- >ia and sclerosis. The other factors m the history confirmed the impression derived from the radiograph that the process was due to hereditary syphilis. Ware calls attention to the occur- rence of syphilis in joints, especially the elbow, secondary to syphilitic osteo- chondritis at the epiphyseal line. The upper epiphyseal line of the radius is hit ra-articular. The secondary results of gumma of bone show in a radiograph taken at a later stage. There may be exostosis. hyper< >.-is of the inner side (if t he r\\x. periostitis, o>-ifie;it i< in df the ril)-. i p-tc(ichindritis. 1 : ; : ...}.< ich. tier liociitsicn., vol. vi. p. IsS. 1.K|J. THE X-RAY RICKETS The characteristic radiographic appearance 1115 in a long bone of a rachitic child is seen at the line i>et\veen the hone and the cartilage. An irregular zone of ossification extends into the clear osteoid tissue. The bowed legs and oilier deformities which often result from the dis- ease are shown in radiographs and the latter furnish valuable informa- tion as to the part of the bone at which an operation should be per- formed or brace-pressure applied (Fiji;. 791). THE JOINTS IN RHEUMATISM The radiographic appearance is described under a grouping based upon Mussor's "Medical Diagnosis" (Philadelphia, 1900). It will be understood that the x-ray alone will not always enable us to differentiate between these diseases. It will almost always, how-over, show that the a chair-invalid in spite- of treatment 1'iir. I'.'L'. Rheumatoid arthritis. Patient I wan i >y hi^h-frcqucncy current.- and tl case belongs to this group of diseases, and not, for instance, to tubercu- losis or malignant disease. The author makes an x-ray examination in every case of this class of disease which lie treats. It is of the greatest assistance in diagnosis and prognosis. A finger-joint, showing ankylosis with continuous bony structure between the two phalanges, as in one ol lilt) MEDICAL ELECTRICITY AND RONTGEN RAYS the author's e-ases, is not going to be restored to functional usefulness by high-frequency currents. Acute Articular Rheumatism.- This disease is accompanied by acute fever. It occurs in early life. There is swelling and redness of one or metre large 1 joints. This may be 1 fugitive, leaving one joint and attack- ing another. It does not tend to attack the 1 same 1 joints on both sides of the 1 boely symmetrically. The 1 .r-ray shows no change 1 in the 1 bones. Effusion into the knee- joint is almost always recognizable in the 1 radiograph, the 1 floating patella and the 1 pouch under the 1 quadriceps tendon being evident. Chronic Articular Rheumatism.^ This is a disease of later life; the 1 history of heredity is very marked. It affects several of the large 1 joints, especially the shoulder and the knee. There is spontaneous pain as we'll as te'udcrness most of the time, but with exacerbations, due in some of the author's cases to weather changes in either direction. There is no impairment of usefulness in these joints between attacks, except in some 1 verv chronic cases, where there is stiffness or even fibrous anky- losis. It is distinguished from chronic gout by the fact that it presents no spe-cial tendency to affect the 1 great-toe joint or to produce deformities by a de-posit of sodium urate in the 1 ears, fingers, and about the 1 joints. Rti(lio(/r(i])liic(tlli/ these 1 joints present very little 1 change, the bones show no rarefaction, and it is only in very chronic case's that there is some irregularity in the bony outline and an unnaturally close 1 apposition of the 1 articular surfaces, indicating partial absorption of the 1 cartilages. THE JOINTS IN GOUT This is a disease 1 whose 1 diagnostic features are 1 the 1 presence of uric acid in the- blood, a deposit of seielium urate' in the 1 jeiints and either tissues, a marked hereditary predisposition, the fact that it is brought on e.-peciallv by errors as to fooel ami drink, and the occurrence of certain digestive and nervous disorders. The trouble 1 very often attacks the great -toe joint . Acute Articular Gout. This may not in the 1 early attacks show any change in the radiographic appearance- of the- joint, but later some of the changes of chronic gout mav be found. The y-rav examination of a joint affected by an attack of acute Sioul shows that the bones are normal, and enables us at once to exclude osteomvelit is, which these cases sometimes resemble. The presence of uric acid in the- blood is determined by means of a .-imple test applied to serum from a blister. A little acetic acid is added ;f gouty tophi in the ear and about the joint s. Tl > radiographic appearance of the bone- is not usually very much C-hanged. evepl that their articular surface.- may be unusually close together, i nd lack senne of the rounded appearance present eel when they are covered by normal cartilage. Deposit.- of uric acid wherever they occur are clearly visible- in the radiograph, forming a mass more- opaque than the lle.-h but not -o opaque a.- bone. THE X-RAY ill/ A gouty tophus consists of a spongy mass o f fibrou.- tiue whose meshes are filled with a white pasty substance. It shows as a clearly defined though not very dense mass in a radiograph. THE JOINTS IN RHEUMATOID ARTHRITIS OR RHEUMATIC GOUT This is a disease which often seems to be caused by repeated preg- nancies or by privation, and is of slow and intermittent but determined progress without fever. There is no special hereditary influence and no uric acid in the' blood. The vast majority of the cases are subacute or chronic. It is essentially a bilateral, symmetric disease of many small articula- tions, but some larger joints may also be involved. Subluxation of the finder joints or of larger joints may occur. There may be changes in the outline of the joints due to absorption or to osteophytic processes. The osteophytic growth may cause loss of mobility in the affected joints. The hand in a typic case of rheumatoid arthritis presents a character- istic deformity. Kvery finger is more or less affected. The first phalanx is either flexed or extended and the last phalanx is either flexed or extended; there mav be simply flexion of the first phalanx while the others are st raight . The hand is pronated and the fingers turned toward the ulnar side. The ends of the phalanges may be enlarged. Uheumatoid arthritis differs from chronic articular rheumatism in its bilateral and polvarticular character, the absence of acute attacks brought on by climatic conditions, the greater deformity produced, and the possible involvement of the articulations of the spine. Chronic rheumatism is more 1 apt to affect the heart and to present a history of chorea. The radiographie appearance in rheumatoid arthritis corresponds with the apparent condition of the joint. The articular ends of the bones present the normal degree of translucency to the .r-ray, but there are irregular knob-like projections. Some of these appear more trans- parent, and others have 1 about the same transparency as ordinary com- pact itone. In one such case the joint ben ween the proximal and the second phalanx of the left index-finger was permanently and irretriev- ably ankylosed. There is continuous bony structure right through this joint. The case is one which was sent to the author for treatment, and it was important to know the condition of the different articulations. HYPERTROPHIC ARTHRITIS OR OSTEO-ARTHRITIS This is a slowly progressive disease occurring in later life and in both men and women. The joints are enlarged, painful, and tender. Formation of new tissue takes place at the junction between bone and articular cartilages, and this new tissue becomes calcified, forming Heberden's nodes, but these eventually break down and destroy the contour of the articular .-urface. A radiograph, made at this time, will show a very irregular disorganization of bone, which can easily be differentiated from the more or less symmetric destruction seen in the atrophic type of art hrit is. 1 Chronic osteo-arthritis is the name given by l.avensoir to a case in which radiographs by Pfahler showed that some of the joints in the fingers were obliterated bv fibrous or bonv union, and others in the fingers and haiuls by the absorption of bony tissue. There were several luxations. Fitch. X. V. Staff Journal of Medicine, vol. vii, Xo. 7. April. 1. 77. I'.KHi. THE X-UAY 1110 Figure 7<>1, p. K)S('), is of an dhow from which several ounces of gon- orrhea! pus had been evacuated a few months previously, and Fig. 7<).j shows a hip-joint from which several ounces of pus. 'also containing gonococci, were evacuated a few months after this examination. Neither of these radiographs show any visible abnormality. Of course, if pus had been present at the time the radiographs were made the fact of fluid in the joint would have been discovered by the radio- graph. Pus shows about the same density as water or as the soft tis- siie> i 'f i he body. Inn a considerable collect ion of any kind of iluid almost alwav- .-how-; a di-tmci boimdarv m the radiograph. ( 'ases of destruction from an morrheal arthrii- are rare and -how a radiographic appearance -imilar to ihat of tuberculosis. ( 'ases of ankylo-i- are not -o uncommon. '1 he radiograph does not -how bony ti-.-ue extending aero-- the .-pare between the bone- nor exo-to-e- about them. The process is one of fibrous tissue formation. ill2<) MEDICAL ELECTRICITY AND RONTGEN HAYS TUBERCULOSIS OF BONES AND JOINTS The principal feature- are i. The ,r-ray shows at first increased translucency, then some loss of detail in t he bony si ruct ure. and then wasting away of t he part affected. There is usually no tendency to the production of exostoses nor to the depo.-it ot bony tissue in peno.-teal swellings. The areas of rarefaction are sometimes so clearly defined as to indicate practically tubercular abscesses of bone. In other radiographs the rarefaction of the bone presents no sharply defined border separating it fn iin the unaffected bone. It is a very important fact that the increased translucency extends beyond the limits of actual disease. There is more or le-s i'a refaction and atrophy of other bones beyond these limits. Reiative Diagnostic Value of the ,r-Ray and the Tuberculin Test. \V. S. Haer and II. W. Kennard discuss the diagnostic value of tuberculin in orthopedic surgery. 1 It gives an earlier diagnosis in some cases of tubercular joints than is obtainable by the radiograph almie. The ophthalmotuberculin test is extremely simple and convenient and does not cause fever or other constitutional disturbance. A few drop.- in the eye are said to cause a local reaction there, if tuberculosis i.- present in any part of the patient. It is not mathematically certain however. Tuberculosis of the Hip. For this disease see p. lOtii). Examples of Tuberculosis in Other Joints and Bones. A valu- able series of radiographs has been published by K.xner. 2 They//-*/ <, a radiograph of a fish, was made with the 1 portable' high- frequeney coil apparatus (Browne 1 . Salem. Mass.). Figures T'.'t) SO;-) are raeliographs showing t he' inje'cted blood-vessels of normal human subjects. They were made for the 1 author by Mr. Brush of t he Met ropolitan 1 lospital. Rontgen ray may lie used in studying postmorte'in anatomy any limitations as to length and strength of exposure 1 , and 1 advantage 1 derived from absolute' immobility ami the injection ilood-vessels and other hollow organs with e>paque substances transparent gases. Pictures produced in this way show the' ssels in their natural relation?-, undisturbed by elissect ion. hollow and solid abdominal viscera with a MEDICAL ELECTRICITY AND RONTGEN RAYS Fi<_'. 7U5.- Radiograph <>f a fish. THE -KAY HIM MEDICAL ELECTRICITY AND RONTGEN RAYS I i:' ,'>>. Injected iirterie- of t lie Confirm, including; t lie deep palmar arch. THE X-RAY 1 1 25 1120 MEDICAL ELECTRICITY AND RONTGEN RAYS THE X-RAY 112S MEDICAL ELECTRICITY AND RONTGEN RAYS r~ THE X-RAY 1120 more clearly defined outline than is possible during life, with its respi- ratory, circulatory, and peristaltic movements. The diagnostic value of these pictures lies in their use as charts for the interpretation of radiographs made from living patients. The author's radiograph of the different pneumat'c sinuses of the face filled with lead shot are examples, and also Proust and Sefroit 's 1 radiographic studies of the topography of the pelvic organs. r \ ne latter show espe- cially the relations of the injected blood-vessels and the ureters. ANATOMIC AGE DETERMINED BY RADIOLOGY The late Dr. Kotclr introduced a >ystem of determining the develop- ment of t he child and its fitness for work in the school or the gymnasium or the factory, by radiographs showing the osseous development of the wrist. The following is his table of ossification as determined radio- graphically: A. First yr;ir ( >s magnum, uneifonn. H. Second to third year ( )s magnum. unciform, lower epiphysis of radius. ( '. Second to third year ( )s magnum, uncit'orm, radius, cuneiform. 1). Second to third year ( >s magnum, uncifurm, radius, cuneiform, semilunar. K. Third to fourth year ()s matumm. uncit'orm, radiu>. cuneiform. M'miluiuir. trapezium, or scaphoid. Filth to Mxth year Os magnum, uneifonn, radius, cuneiform, semilunar, trapezium, scaphoid. Sixth year Os magnum, uncit'orm. radius, cuneiform, semilunar, trape/ium, scaphoid, trape/oid. Sixth to seventh year ( )s maiiiium. uncit'orm, radius, cuneiform, semilunar, trapezium, scaphoid, lower epiphysis of ulna. 1. Sixth to seventh year Same as jjroup II as to number of bones, but more advanced in development. .1. Seventh to eighth year. . . .Same as jjroup I, but more advanced in development. K. Ninth to eleventh year. . . .Same as . Pryor i l<>o:>. UHlti, and 1908), Kotrh i I'.HM) and 1 ( .) 10), and Smith i 191M>. Tlie last mentioned feels that the method is of little value in the case of naval cadets, eighteen to twenty-two years of au'o. It >hoiiid be applied at an earlier period and then may indicate future fitness for the work. 1 P:iri< Sucii'te Anatomique, March '27. I'.Hls. - The Development of the Hones in Karly Life. Studied by the 1'ont^en Method for the 1 ). term ination of an Anatomic Index. Trail-action Amer. 1'hys. Assoc., vol. .\\i\-. p. lit': 1 ,, I'.iu'.t. 1 Interstate Medical .Inurnal. Mav. l!i:i. lloO MKIHCAL Kl.K< THlrlTY AM) KnXTCJKX KAYS DETECTION OF PEARLS IN OYSTERS The tiiu>worn method has been to open the shell and kill the oyster. This results in the needless destruction of millions of pearl oysters containing no pearls and of thousands of oysters in which there are seed pearls which would increase' ten-fold in value if the oysters were allowed to live another year. Experiments by the author evolved a method for radiographing 121 oysters at a time and the process has been in actual il>e in ( 'eylon. Tin- ('/untie Kfl'rct* <>f th< .r-Iitii/. These are not striking. Starch i- -lowly changed into dextrin by .r-ray exposure. Water exposed to the .r-ray for one hundred hours showed no scpara- ii' in of oxygen and hydrogen gases. 1 PHYSIOLOGIC EFFECTS OF THE XRA.Y FROM MILD APPLICATIONS A -innle mild exposure produces no perceptible effect, but some- -en-ation i> felt a^ of proximity to a source of static electricity. picture or niakiim a fluoroscopic examination is an example of ilicat ic in. ( ' persons notice a perception of liirht when their eyes are ' \: ii -'- iv 1 ) irn and Flit hol'f i . 'I ". ha~ liecn found to constitute a very delicate te. --Radi ([uently repeated mild doses is to produce one of the lesions described under the head of x- ray dermatitis; another is to produce sterility. There is no immediate systemic effect perceived by the patient from ex- posure ot even t ho entire surface 1 of t he body to a >ingle mild application. Repeated exposure 1 to mild doses has the efleci of impairing the vitality ot rapidly growing cells. The embryo may be killed in utero by a number oi exposures which art 1 without any appreciable effect upon the mother. For example, to watch the course of gestation in a cat. which had been the mot hoi 1 of several families of healthy kittens, the author took a number ot .r-ray pictures, beginning before any evidences of gestation were present and continuing at intervals of about a couple 1 1 :V2 MEDICAL ELECTUICITY AND RONTGEN RAYS of weeks down to a day or so before confinement. In each case the author's own hands rested upon the cat to hold her in position upon the photographic plate, and were as much exposed to the .r-ray as was the cat. The exposures were 1 mild and short. \o effect was produced upon the cat herself and none upon the operator's hands (this was a dangerous experiment), but at the natural time three mature and perfectly formed kittens were born dead. The exposures to the .r-ray were -topped, and the cat proceeded to have another family of four kittens, which were born alive and healthv two and a half months after the others. 'I 'In' del ails of the exposures to which t his cat was subjected are iriven 10 || s '.i it Hi TIIK J-KAY 1 1M '1'his is the effect to he expecteil, and it is regarded as undesirable to make repeated radiographic or lluoroscopic exainitiat ions of the pel- vis of pregnant women. That the .r-ray will not always kill the fetus, even when vigorously applied, is quite certain, and cases are recorded in which .r-ray treatment for cancer of the uterus has not interfered with the progress and completion of normal gestation. 1 Probably a single ./'-ray examination of the pelvis would not affect the vitality of the embryo. Repeated applications of the .r-ray to the pelvic organs would be very apt but not certain to do so, and would assuredly be justified in the treatment of malignant disease. In the case referred to above the child was not killed bv the .r-rav. but probablv actually owes its life to the .r-ray, which restored the mother to apparent health and enabled her to go through gestation and give birth to a healthy child. There is no effect upon the embryo from the application of the .r-ray to other parts of the patient, and in this case the pelvis should be protected from the rays either by a localizing shield about the tube or by tin .r-ray proof covering over the abdomen and pelvis. This cov- ering may be a sheet of .r-ray metal or of the soft .r-ray proof rubber, which contains a certain percentage of bismuth, baryta, or other heavy met allic powder. Repeated exposures to the .r-ray will retard the development of new- born animals. Tribondeau and Recamicr have verified this observa- tion in the case of a kitten. 2 The development of the eyes was arrested and structural anomalies of the retina were produced. The develop- ment of the teeth and of the bones of the face was much retarded. Action ofthex-Ray {' pou the Dcrelopn/cnt oj the Entl\i/o of tin Clilckoi* Fifteen Holzkneeht units of .r-rays prevent the development of the embryo of the chicken or arrest its development if it is already com- menced; the biologic properties of the albumin are clearly modified by the .r-rays; the albumin becomes less coagulable, and it is more diffi- cultly digested by pepsin; these facts may explain the arrest of de- velopment of carcinoma treated by the .r-ray. Effect on Microorganisms. Experiments upon the effect of the .r-ray on microorganisms have been made by Russ. 4 Looking at the cultures on the lens of the microscope itself while exposed to the ome microorganisms do not appear to be influenced. These are s proteus. Vibrio cholera 1 , and Trypanosome Lewisii. Others, acillus typhi. Bacillus coli, and Bacillus pyocyaneus. show rapid disordered movements. Kven long and strong exposures to the .r-rav do not interfere with the growth or virulence of different micro- 1. l.evitv' says plant* c.r/ioxcil to x-i'/ suitable for cancer tin 1 not in- jured by it. Plants inoculated with H. titnicfacienx developed crown- nless .r-rayed: then they did not. lie found no evidence that irritated or stimulated the tumor u'rowth. Sterility from Rontgen Radiation. Repeated mild exposures of the < vary or test i- are quite generally regarded as productive of sterility. In the case 1 of .r-ray operators the loss ot the power of motion in the 1 LaqilciTHTi 1 Mini Lalicllc. Bulletin < MiiricI . I'.tO.V ' Bonlirr and (lalinanl, Arch. d'Klcrt. Med. K\p. et Cliniq., i:;. I'.tl. July in. I'm:,. 1 Arch, !'. Hyuiene. vol. Ivi, p. Mil. 1'ttiii. & Aiucr. Jour. Kleetrntherap. and Hadiol., vol. xxxvi, No. 15, March, 1'JlS, p. 1 lii. 1 bvl MKDH'AL KLKCTHICITY AND KONTCKX KAYS spermatozoa, and in some rases absence of the spermatozoa, has been demonstrated a great many times by the microscope. The fact was first published by Tilden Brown and A. T. Osgood. of Xe\v York. This is not accompanied by any sexual impotence, and it is doubtless not permanent, but a condition which disappears after the exposures 'nave been discontinued or protect ion by a proper apron or shield has been adopted. 1 his necrosperniia mav develop in anyone who spends much time in an .r-ray room where no precautions are taken to limit the rays to sonic one particular direction. The effect upon the testicle from repeated moderately severe applica- tions of the ./--ray has been studied by Bergonie and Tribondcau. 1 Six while rats were used, and entirely protected by sheet lead except where 1 the testicles were exposed. Rat one, five applications of 2 Holzknecht units at intervals of eight days; rat two, nine applications of 1 H. at intervals of two days; rat three, eleven applications of 2 H. at intervals of two days; rat four, ten applications of 4 II. at intervals of two days. These rats had all had one testis removed before the experiment. The one exposed was removed and examined a month and a half after the last exposure. Rat five, both testes exposed five times to 4 H. at intervals of eight days, one testis removed immediately after the last seance, the other a month and a half later. The result was the same in all. There was no change in the skin or hair, but there was a great change in the testis, consisting in the substi- tution of a serous liquid for the peripheral parenchyma, the same liquid separating the deep parenehymatous tubules, and a breaking down of the epididymis. A male cat may be sterilized by .r-rays filtered through 2 mm. of aluminum and with a dose of about 4 Bordier applied in one or two seances. The oviform cells survive, but disappear sooner or later. The same authors have measured the dose required to completely and permanently sterilize a male dog.- and in the latter case have 1 shown that the refractory oviform cells are incapable of regenerating epithelium. The histologic changes are found, in the seminal epithelium of the testis, which is the source of the spermatozoa, and not in the interstitial glandular tissue, whose activity is the cause of the sexual instinct and sexual activity. The secretion from the interstitial gland is an "inter- n;il " one. and is concerned with the maintenance of all the masculine characteristic.-! of the general system. 3 Observations on animals show thai repeated mild exposure of the pelvic region results in the ovaries ceasing to produce Graah'an iollides. Thi- effect i- probably temporary. Two hundred minutes' exposure of one ovarian region of a rabbit lie ot her ovarv was shielded produced very marked atrophy ot t lie ,.. ;md disappearance of the (iraafian follicles. I lalberstadtcr iio-ure iii t went v davs in divided doses, and found t he ovary ;j/e of I he one m it exposed. Return of Spermatogenesis After .r-Ray Exposures. The iiow- of c;ise- in which physicians working much with the . . ; roteclion have been luiind to have complete i'l : ,-ricit. 1 \I'-i:<':tl.'. Bordeaux, Krmri', l-Vh. 2."i, I'.Hir,. ( . I! , : i l: . .! !;i Sue. .',.- Bi.,1 .. l\\. :.. .l.-ni. 7. I'.M 1. :nnl 1\\, f>n. .! \ v . - : ' -. l';iris, vol. f\lii. |> , _':;. ' \ ; . !_'. I', 1. .hll. |li, I'.HI.Y THK r-HAY 1135 necrospcrmia and apparent azoosperrnia, and in whom a vacation, and tlie subsequent use of a heavy apron of rubber loaded witli baryta, and an efficient shield around the .r-ray tube, have been followed by the reappearance of living spermatozoa, and the men have had children. Laquerriere 1 re])orts a similar case, in which the return of sperma- tozoa was followed by conception. A patient of Dr. Lapowski's- was a man with pruritus scroti, who was treated by the r-ray. Previous microscopic appearances were nor- mal, but after two applications of ten or fifteen minutes, at a distance of 15 cm., there was necrospermia. The treatment was repeated twenty days later, and after that There was azoospcrmia. Five months later, however, living spennato/oa were present. Phillips' cases, purposely sterilized, were found to be still so six mon) hs later. A'-ray workers who have found that they were sterile have kept out of the .r-ray room altogether, and have after a year or two had children, and then have resumed r-ray work and have had no more children. ( Mliers have found no living spennato/oa, in fact no discoverable sperma- tozoa at all, and after a couple of months' complete absence from x-ray exposure, followed by the use of an opaque apron and of a shield to envelope the tube 1 , have found living' spermatozoa again. Absence of Effect on Spermatozoa Outside the Body. Human spermatozoa, after leaving the body, are not greatly influenced by the .r-ray. Their vitality, according to Bergonie and Tribondeau, 3 is not modified by an exposure of half an hour, at a distance of 15 cm. from the anticathode. Precautions to be Taken. When repeated applications of the .r-ray are required the ovaries or testes should, therefore, always be protected from the .r-ray. Baldness. Repeated mild exposures result in thinning or loss of the hair. This is only temporary, but should be guarded against. Toxemia. In a number of cases which have been reported, and the author is sure that many others have not yet been reported, and some have not been recognized as attributable to the ,r-ray, a single thera- peutic or diagnostic application of the r-ray has been followed by seven 1 constitutional disturbance. The author has seen this occur after the first mild application for cancer of the breast, and it has been noted in leukemia and other conditions in which applications are made with a view to an effect upon a constitutional disorder. I Msall's observations* upon cases of leukemia, unresolved pneumonia, pernicious anemia, and gout treated by the r-ray show that when a single application produces an immediate marked effect, beneficial or otherwise, the examination of the urine and other means of stud}" usually show that destructive metabolism has been, for the time being, enormously increased. Some of these patients were on a regular diet containing a measured amount of nitrogen, and the amount of nitrogen excreted had been watched for a few davs before the .r-ray was applied. In some cases the excretion of nitrogen during the next twenty-four hours was almost doubled. These cases with increased excretion ' t. '< iniiiv-'s of the French Association for the Ailv:inc on Medial I-:i.-ctri"ity, Lyons, Auu;., 190*1. - Bnnvn ait'l <>>u;d's Article. Am. .lour. Surgery, 19U.~>. Xo. 0. ;i ('. !!. de la Socirte do Bio!o L n.', 57, /W.">. Dec. ii. I'.HH. 4 University <>f Pennsylvania Medical Bulletin, Sept., 190.~>; Jour. Am. Mi Assoc., Xov. :;.' I'.tOti. Hot) MKDH AL KI.KlTKIClTY AM) KONTCKN HAYS included patients with leukemia or with unresolved lobar pneumonia, and were favorably influenced by the .r-ray applications. The increased metabolism may be due to an effect upon the tissue ferments. The cases without an increase' in nitrogenous excretion were unfavor- ably influenced, and some were apparently even killed by the .r-ray application. It seem.- from the' studies already alluded to, and also from those of Kdsall and Pemberton, 1 and of Musser and Kdsall.- that these- we're case's in which the- large breaking down of nitrogenous tissue -ub-tances was too much of a tax for the eliminative organs, and that the latter were overwhelmed and partly incapacitated by the unusual demand upon them. 'Ihe result in some cases was a toxemia caused bv the excess of broke-n-down products in the system. According to these authors, the- application of the .r-ray to any considerable portion of the beidy, especially if the hematopoietic organ-, such as the spleen and the marrow of the long bone-s are exposed, ivgularlv produces a tremendous increase in the- destructive meta- morphosis of nitrogenous tissue substances, such as mu'leoprotein, and this calls for increased activity of the eliminativc functions. The effect under consideration is not that of a large' and toxic dose; of the .r-ray, but that of a single' therapeutic or diagnostic application, which under ordinary circumstances produces no apparent symptoms. Kdsall says that he knows of no drug or other therapeutic agent which produces an equal effect in ordinary dosage. The cases in which this increased tissue destruction is liable to produce a harmful effect are those in which the patient is already in a toxemic condition, or in which there is nephritis or some similar dis- ease which interferes with the elimination of waste products. \o constitutional effect results from such an application of the' .r-ray as is required for treat ing an epithelioma of the face', or for making a radiograph of the hand, if the rest of the body is shielded from the rays. Hut when the body is not shielded, even though one of the- extremities may be nearer the .r-ray tube, and consequently receive a stronger exposure, a constitutional effect is produced. This is also the case 1 when the .r-ray has to shine through a large part of the' chest or ab- domen tor examination or treatment. Harmful constitutional effects may be avoided, whether the patient is in a favorable condition or not, by shielding all but the portion of the patient which it is desired to examine or treat when this is a small and not a vital part; also by making sure that the patient is in a healthy condition "> cases where a more general expo.-ure or one involving the -' or abdomen is required. Such applications to a patient suffering i the tovniia of cancer, pernicious anemia, leukemia, or other ilar disease, or with elimination crippled, as m cases of nephritis, -hould generally be avoided, but il necessary .-hould be cautiously made. I he effect which is under consideration has not usually the cumula- iracter shown bv the effect upon the -km and some other < irirans. ! iiil ary, a -ingle mild general application may be followed bv :."-' profound constitutional effect, while a number of similar ap- ' "li -ucces.-ive (lavs may not produc* 1 any change in the ap- i' effects of a single severe application are not perceptible at the ; ime, b n develop after one to seven da vs. 'I hey a re clueflv upon the V, Jour. Me, |. Sciences. I 'ebruary ;ml March. I'.mT. * I nivt T-ity of Pennsylvania Medical Bulletin, September, l'.H),">. superficial tissues, and vary all the way from a slight erythema to a destruction of tissue ri<;ht down to periosteum, which may lake months to heal or which may never do so. The lesser decree is often required m the treatment of disease and is not accompanied by visceral changes. The very greatest decree has onlv been produced in observations on animals alonu' the spine it has resulted in men in ^it is and death: over the abdomen even the greatest decree of overexpnsure has not produced ^TOSS changes in the Castro-intestinal tract. Enough has been said to show that the effect of a single very excessive exposure; is so disastrous that the ./--ray should never be applied at all by one unfamiliar with its dos- age. All the elements which ,uo to make up a knowledge of the correct do.-e and the way to apply it, either for diagnosis or treatment, are of the verv greatest importance. Repeated severe applications have a cumulative effect if u'iven at intervals of less than one or two or three weeks. The least severe application which will produce a visible effect upon the skin of the face is about o 1 lolxknecht units (o 11.), and this may be repeated every three weeks without doin.u' more than maintain a sliji'hl reaction. If this dose is ^iven more frequently, or if a larger dose is li'iven at the same interval, an increased effect is noted from each application.. Another fact of importance is t hat a surface which has once shown a reaction to the .r-ray is more susceptible for a ]on,ir time after- ward. Experiments reported by I leinecke. of Leipzig, al the (ierman Medical Congress of I'.tOl. show the effect of prolonged exposure to intense radia- tion. His studies were especially upon the lienuitopoietic organs, and the animals were exposed to the x-ray for ten or fifteen hours at a stretch. In the marrow of the lonir bones there was almost a complete disappearance of the characteristic lymphocytes, only red cells beintr present. Xo <:TOSS lesions were present if the animal was killed imme- diately after the irradiation, but at the end of a week they were always found. In the first four hours after irradiation, in do^s. a microscopic change was noted in all the lymphatic oriran.-. the spleen, the intestinal follicle.-, the lymphatic glands: this change consisted in a destruction of lymphocytes and their absorption by phagocytes. This abnormal condition had disappeared at the end of twenty-four hours. 1 he temperature may be elevated, and the do<_r may lose as much as one- four! ii of his entire weight in twenty-four hours, '1 he Malpi amperes. 1 he dis- tance iVoin the animal was '_'() to 10 cm. > s to 1(1 in.), and the duration 1.5iS MKDKAL KLKt THHITY AND RoNTdKN HAYS of exposure in mice was from two to ten hours. Mice, which were exposed four hours or longer, died in a few days as a consequence of the destructive effect upon the blood-forming elements in the spleen, the lymphatics, and the marrow of the long bones. An important fact i- that the fatal effect was produced whether the exposure was a con- tinuous one or was divided up into several exposures of fifteen or thirty minutes each. Kven as short an exposure as fifteen minutes, while not producing fatal or even serious effects upon the animal, caused necrotic foci in the spleen, which could be found if the animal were killed soon after the exposure, but which were 1 almost normal again if the animal was not killed until eleven days later. Krause and Xiegler exposed guinea-pigs for ten hours with similar temporary effects upon the blood-forming organ.-, but without a fatal effect. The same ten-hour exposures produced similar results in dogs. Sterility in men appears from Phillip's cases to 1> produced by an exposure of one hundred to two hundred minutes to a ray of moderate intensity, but as this was enough to produce excoriation of the scrotum, divided shorter exposures, distributed over a number of weeks, could produce this effect upon reproduction without the effect upon the skin. Occasional microscopic examinations would show when necrospermia or a/oospermia had been produced. The exposure required to produce falling of the hair is susceptible of quite exact measurement, as explained under the head of .r-ray dosage in the chapter on Radiotherapy. The effect is produced either by a single exposure, amounting to from 4 to 7 Hol/knecht units, or by several exposures aggregating the same amount. Workers with the .r-ray should have the ./'-ray tube enveloped in a box made of material opaque to the .r-ray except in the direction in which the latter is to be applied, and in using the fluoroscope should have the fluorescent surface covered bv lead glass. The latter protects the eves also. . A cap lined with sheet lead affords very good protection for the operator's hair. An apron made of sheet rubber containing a large percentage of baryta protects the body and genitals, (iloves containing baryta or lead oxid protect t lie haiii Is. Kienbock observed that mice which were exposed for several hours to the .r-ray applied over the back, developed severe nervous svrnp- toms in about three days. The eyes were closed, the spinal column flexed, and there was spastic paralysis of the limbs. The mice died. Similar exposures, t hough -t rong enough to cause the hair to fall out and to produce dermatitis, did not cause symptoms of disturbance of any internal organ m guinea-pigs and rabbits. inal con I. cposed a pigeon to the ./'-ray and ob.-erved falling out of \'~. not onlv on the .-ide toward the ./'-ray tube but al-o on . from the tube. The latter was apparently caused bv ray- i traversed the entire thickne-- of the abdomen without ' 'ft upon the mt ernal orga us. The Effect of the .r-Ray Upon the Eye. Tin's | 1139 lively studied by Rirch-Ilirschfeld. 1 He has not found any change' in the retina except in cases where the exposure has been severe enough to produce clinical changes in the eye. An exposure of 10 or 'JO II.. however, produces changes which may attect clueflv the anterior or the posterior structures of the eye in different cases. There is a period of incubation lasting from fifteen to forty-one days. There is a characteristic effect upon the epithelial cells of different parts of the eye. Those of the cornea become irregular and swollen and their nuclei become flattened out and sometimes divided. There are also some degenerated and vacuoli/ed cells. The conical e[)it helium mav be desquamated until onlv a single layer remains, and may then be gradually replaced. The eyelashes fall out . These are the changes in the inner walls of the blood-vessels detailed in the general description of the physiologic effects of the .r-ray. The iris undergoes swelling and loosening of its epithelial cells and degeneration of the pigmented cells in its stroma. The crystalline lens and its epithelial cells are unaffected. The effect upon the retina and optic nerve becomes visible at the end of sev- eral weeks. The ophthalmoscope reveals atrophy of the optic papilla. The microscope confirms this, and also shows degeneration of the gan- glionic cells of the retina, with vacuolization and a characteristic change in t heir ehromatin. This coloring-matter does not disappear as its does from the effect of the ultraviolet ray, but divides up into numerous small particles. It becomes "pulverized." There is degeneration of the optic nerve-fibers, which Birch-Hirschfeld considers secondary to the degeneration of the ganglionic cells, and not due to a direct effect of the .r-ray on the nerve-fibers. An < >/c irhifh )x exposed to the .T-rni/ in the course of tJie trcatint nt of a cancer of the e>/eli(l gradually becomes affected, although the sight ma}' not be destroyed for many months. The eye begins to look smaller, the conjunctiva reddens, and the cornea becomes opaque, not whitish, but because it is covered by newly formed connective tissue. This tissue contains blood-vessels and round cells and is covered by several layers of epithelium of a character similar to that of the skin. The ///'* is infiltrated by leukocytes; most of tin' pigmented cells disappear; the walls of its blood-vessels undergo the usual effect from the .r-ray. The retina- shows the usual r-ray degeneration of the ganglionic cells and of the intima of the blood-vessels. No change is to be discovered in the optic nerve-fibers. There is a very marked change in and near the macula lutea. Cysts develop which thrust aside the internal gran- ular layer. There are spaces of almost normal retina between these circumscribed cysts. The eye is permanently destroyed. This effect may be guarded against by usini: sonic kind of shield protecting the whole orbit, or. if the evehds are to be treated, the eveball may lie protected by an opaque s and under the eyelids. The model, shown and ha> a ] >r> tject i< n\ on its ext erna 1 M-rt inu' and removing n . 11-10 MEDICAL KI.KCTKUITY AM) ROXTCJEX KAY: about the eye be limited to malignant and tubercular disease of the eyelids, and that not more than S or 10 H. should he applied once in two \veeks. These conclusion- should probably he modified. The dosage seems unnece-sarily and. then-fore, undesirably lariie, and the x-ray has been used safely and with excellent results in trachoma. Effect of the ,/r-Ray Upon the Liver. Experiments by TTudellet 1 .-how that in the adult rabbit it causes only some interference with intercellular nutrition in the liver. In a voting rabbit it causes a certain derive of atrophy without necrosis. The liver of a newborn kitten undergoes changes amounting to destruction of the part of the liver directly exposed to the rays. Each exposure was usually the same except as to duration. A D'Arsonval-( iail'fe transformer was used with 1 ma. of secondary current and Xo. 7 Kenoist rays, the distance from tin 1 ant icat hodc to the skin being l.~> mm. The exposures in two adult rabbits were one hour and two hours respectively. The young rabbits were exposed over the region of the liver foi about ten minutes every day for twenty day.-. A newborn kitten received exposures of ten minutes every other day from the third to the' twenty-first da)' after birth. Effect Upon the Nervous System.- Scorbo. of \aplc-. has noted a neui 1 "": i-ciilar tr.iphic action of the r-rav. >' '. ej-al author-, including Schaiv have reported the occurrence of IH-rvo . - i -t MI 1 1 a lice- alter expo- urc to t he .r-i'a y, but I he li'n-a i ma jorit v i'f- have never ob-erved anything of the kind in their pat lent THE X-RAY 1111 The case reported by ( 'olombo' of severe nervous crises following therapeutic applications of the x-ray to the leg may possibly, in the light of Kdsall's observations, be attributed to a toxemia instead of to a direct effect upon the nervous system. Intense radiation of the brain in some of Kodet and Hertin's'-' expeiv ments caused paralysis and convulsions and the postmortem appearance of meningomyelitis. Tarkhanol'P also reported a diminution of reflexes in a frog in which the brain was irradiated. Later observations, especially those of Krause and Ziegler, 1 seem to show that when the whole animal is exposed no effect is produced upon the brain or spinal cord, and the same mav be the case when onlv the nervous centers are exposed. The Effect on the Intestines. The follicles of the intestinal wall are among the tissues which are especially susceptible to the influence of t he ./--ray. After ten hours' irradiation of the entire animal in Krause and Xiegler's experiments (/. r.) intestinal follicles were found imme- diatelv afterward to show necrotic foci, but these had disappeared if the animal was not killed until four days later, and a clear area, consisting partlv of epithelioid cells, was found at the center of each follicle. The effect on the intestines is really part of the effect on lymphatic tissue, which occurs wherever this is to be found. The eff'-ct on the skin is a breaking down of the hair follicles, edema, and disintegration of the epidermic cells, hyperkeratosis, and necrotic disintegration of the epithelium, inflammatory exudation into the corium, and thickening of the intima of the large vessels in the skin. JK rd uxc find Zict/lcr found no cfmnycs in the liver, ])dncrcdx, the mneoux 1 a ' le-t rud ive effect upon cell ,-e. V RAY BURNS OR RONTGEN DERMATITIS 1 1 1 ' ; ,- r-ra v | >r< luces a cha Hire in the THE X-RAY 1 143 fatal results. The danger is all the greater beeause there is no sensation of warmth or discomfort at the time. It may be produced by a single overexposure, the irradiation being too powerful, or too long continued, or the tube being too near the surface. The various instruments of precision for measuring the strength and quality of the x-ray are as necessary to proper dosage in examination and treatment as they are to successful picture making. The cumulative effect of successive ex- posures to the x-ray is a source of danger, especially to the operator, and very many of the x-ray specialists in this country have hands which are disfigured by chronic dermatitis. In the worst case the author over saw the patient made and sold x-ray apparatus during the first year after its discover}", and was probably looking at or allowing others to look at the bones in his hand a large part of the time. The apparatus in those days produced a comparatively feeble radiance, so that no immediate effect was noted, but after several weeks of this reckless exposure he suddenly developed an inflammation and gangrene of the back of the hand and wrist. After several months of severe suffering the slough all came away leaving the tendons and the articular carti- lages bare. Healing with deformity finally took place. Of a similar nature at the start were the recorded cases which years later formed the starting-point for epithelioma; and amputation and in some cases even death have followed. There is nothing to indicate that an x-ray burn is an}' more likely to be followed by cancer than any other lesion of similar severity and ehron- icity. Rontgen dermatitis may be of four different degrees: (1) A mild temporary redness of the skin occurs without anatomic changes; it may not develop until two weeks after exposure and lasts for only three days or so. (2) Quite a decided erythema with moderate itching and followed by desquamation of dry epithelial flakes, which may amount to a regular peeling of the affected region; no raw surface is produced and there is no pain; it develops about a week after exposure, and it is three 1 or four weeks before the skin appears normal again; slight atrophy of the skin may remain permanently, especially if a dermatitis of this degree has been repeatedly produced. (-'!) After a period of incubation of only two days a severe dermatitis with blistering occurs, and this is followed by some destruction of the deeper layers of the skin and ulceration which takes many months To heal. It is excessively painful until the sloughs have separated and it leaves a permanent seal'. ( 1-) The most severe degree has a period of incubation lasting for one oi 1 TWO days; begins in much the same manner as the third degree, but it is soon evident that all tin 1 tissues have been destroyed, perhaps to a depth of \ inch. The separation of the slough is very slow and painful, and the ulceration has very little tendency to cicatrize. If at all ex- tensive it ma}' Take years to heal or it ma}' remain as a chronic ulcer. The Chronic Dermatitis of the Hands of ,r-Ray Operators. This is a condition produced bv frequently repeated exposures which individually would produce no effect. The lesion is somewhat of the charar, ;) of a chronic eczema, and leaves the hands seamed, scarred. :""' discolored, with deformed and brittle nails, altogether such a con- dition as would preclude 1 the use of the hand in aseptic surgery. A hand that has one* 1 developed this condition is for a long time thereafter 1144 MF.niCAL KLKCTK1CITY AND R(")NT(iKN HAYS more- suse'e'ptible to the x-ray. Se>me operators believe that there is an aequireel susceptibility to the action e>f the x-ray by which a strength of expe>smv, which would not have 1 affected the 1 operator at the start, may after months' or years' work with the 1 x-ray suddenly produce a dermatitis. In Dr. Pitman's own recoreled experience he suddenly developed a elcTinatitis affecting a large part of the body. The history of the 1 use 1 e>f the' x-ray by very many operators, however, does not lend support to the' theory of a gradually developed susceptibility, but one e-annot toe) stremgly caution those using the 1 x-ray against a gradually developed false 1 se'iise of security. A'-ray Warts.- After some years of x-ray work the 1 skin of the operator's hands may present horny growths which are 1 hard ami black. Some of these project decidedly above the level of the' skin and some are fiat t Plate 14). They seem to be of similar structure to verruca senilis. and there is gn>at danger of their developing into epithelioma. Drs. Kassabian. Caldwell and Leonard, and Messrs, (ireene, Bauer, and Baker are 1 a few of our American x-ray workers who have lost their lives in this way. Their occurrence indicates that the 1 ojxTator has not taken sufficient precautions against exposing his hands. They may be removeel by refraining from x-ray exposure and by applying 10 or 20 per cent. salicylic acid aelhesive plaster. They are exceedingly prone to recur. Another application is undiluted formalin (40 per cent, formaldehyd). A wooden match is dipped in it and the adherent drop is applied, to the wart alone, every three e>r six hours for two or three- days. Smaller ones are killed in a fe-w days, larger ones in a week. After exfoliation the skin should be unblemishe-el; if not, repeat. If ulceration occurs, apply '/me oxid ointme-nt or something similar. 1 The present author has applied this treatment to all of his own keratoses with permanent succe-ss in only one. The first applications produce no sensation; the' later ones are- decidedly painful. Pyrogallic acid. 1"> per cent, solution in flexible 1 collodion, has been u-ed by Dr. L. F. Femen. of Denver (personal communication). After cutting off the wart almost to the bleeding-point an impervious coating is applied to the wart and extends slightly over the sound skin. The- ^olution is applied night and morning for three 1 days, and ofte-n enough te> maintain the coating for a week altogethe-r. At the e-nel of a wee-k it is apt to become very much inflamed and painful, and requires a dressing of boric acid ointment, after relieving the tension by softening the col- lodion and removing it. A black jx-llicle of charred tissue forms which separates spontaneously a couple- of weeks later, leaving a surface that look- like -oiind skin, but which may require one more course of treatment. For the author's own hands this proved unsuccessful. iJcciirrence took place. The treatment is very painful. The d;tily application of lanolin or of cold cream or the like to keratoses j- ,f the ure-atest benefit, and. persisted in. has kept them apparently innocuous and scarcely perceptible in cases where they and fissures (of the palm 1 remaining after x-ray us cured by three chlorin ioiii/at ions. No pig- fter x-ray t real ment .- done in time, i- usually permanently effective-, .July, I'll 2. i; ._:.-: :,. ki-ratiiM-.-; ul the author'* left hand. Tht-sc had prrsi.-tcd for t\vrlvi> IIP m nn\\ I-Vbruary, I'.il.". l)cinu i-un-tl nm< tifii-r jinothcr li\~ radium. I.;ili-r I' 1 -'!! 'hi iippfaraiifi 1 i~ imi very ditYi-n'iii . Inn p;iiiit'ul fi-~nri--- > "i-;i-iuii;ill\- : i In dor-uni nf ihi- iudi-x-fiimi-r. Tlii- inti-rfi-rrs Mjnii-what witli tin- UM- uf tlic r n ii ' ' ; t'l'i tfd n-a- an- ciitirt-lv i TIIK X-RAY 1145 llol/.knecht lias cured about 50 cases by the application of hard, filtered .r-rays and an equal number by the gamma rays from radium (page 12(>9)." The author has cured several cases by unfiltered radium rays, apply- ing the glass tube directly. Electrolytic actions take 1 part in the production of Rontgen erythema, as pointed out by Bordier and Salvador, 1 but the present author be- lieves that the x-ray is the exciting cause of the electrolytic action, and that there is no means of entirely preventing it except by interposing something entirely opaque to the .x-ray. The experiments of Strater, Kienbock, Oudin, and Scholtz seem to leave no room for doubt that radiodermatitis is due to the x-rays and not to electric discharges and other physical phenomena which take place around the tube. PRECAUTIONS AGAINST RONTGEN RAY INJURIES General Precautions. Measure the intensity of the x-radiance your apparatus produces and learn the safety limit of its application. Prac- tice upon inanimate objects until you have learned to produce a quality of x-radiance which w r ill have the desired effect with a safe exposure. Remember the cumulative property by which several short exposures have as great an effect as a single prolonged one. Remember that the danger varies inversely as the square of the distance from the anticathode to the skin. 1. Precautions in .r-Ray Examinations. A. Protection of the Patient. 1. Theuseof thoj^woroscopeis fraught with the greatest danger, and I believe should be abandoned. If, contrary to my advice, it is employed on rare occasions, the strength of the radiance applied, and consequently the safety limit of exposure should be determined before- hand, and strict account should be kept of the actual exposure. A number of short exposures have an effect equal to one long exposure. Only the requisite part of the patient should be exposed. The x-ray should be filtered by passing through a thick screen of sole leather or aluminum. The anticathode should be 18 inches, and in most cases much further from the nearest surface of the body. The portions which are to be especially protected are the eyes, the testes, and the blood- forming organs such as the spleen. The greatest danger arises when a long examination is made or a long operation is performed, as for the removal of a foreign body under the fi Horoscope. 2. In radiography the strength of the radiance employed and the safety limit of exposure should be determined beforehand and the fact of the cumulative effect of several exposures borne in mind. Cinemat- ographs of a thick portion of the body requiring prolonged exposure, even with an intensifying screen, are contrary to my advice as involving a total exposure which may be dangerous. The effect of an x-ray ex- posure (Iocs not disappear for at least three weeks. A heavy sole-leather or aluminum screen should be employed and only the requisite part of the patient exposed. The anticathode should never be less than i;> inches from the nearest surface of the body, and should be considerably further away when a thick portion of the body is to be depicted. An intensifying screen, reducing the exposure to about one-tenth, should be u-ed whenever a radiograph is to be made through a thick portion of a very large person, or when a number of radiographs are to he made '('. I!. Acad. Sri., cxxviii. Kil'J, June 2(i, 1 *<)<). 11-k) MKDICAL KLKfTHK ITY AM) HUNTCKN HAYS through a thick portion of even ;i small person. The greatest danger arises when a more difficult case is attempted than ever before, and the most important tiling is to place the tube at an increased distance from the skin. Leukemia and renal insufficiency necessitate caution as to any strong general exposure of the abdominal organs. The proper ([iiality ot .r-ray is important; too low a decree of penetration lias an excessive effect upon the skin with too little effect upon the plate, as so much is absorbed by the tissues. The unfluctuating current genera- tor, producing .r-rays of approximately uniform wave-length, is an ele- ment of safety in radiography by reducing to a minimum the admixture of . Protection <>j tin- Operator in x-Ray Examinations. 1. Never make direct use of the fluoroscope, '2. Never use any portion of your body as a test-object for measuring the quality or the intensity of the a'-ray. '.). Do not use a fluoroscopic penet rometer, but always make a radio- graph of the pcnet rometer in testing a new tube or new conditions. 1. Do not hold the film or plate in position yourself. .">. Never remain in the room with an unshielded .r-ray tube in opera- tion. 1 . Mm in iscopy, (luring which the operator stands beyond the patient in a direct line with the .r-ray, if many times repeated, means certain injury and frequently death. The danger to the operator may be ob- viated by his -landing behind an impervious screen and viewing the fluoroscopic linage in a mirror. 2. The phy-iciaiis who have died from .r-ray injuries have been vic- tim- chiefly of the habit of looking at the bone- of the hand as a means of testing 1 he quality and intensity of the .r-ray. The manufacturers ./-ray a p pa rat us are often asked by prospective customers to allow the ./'-rav to shine through the chest or some other part of the bodv, so thai the customer may see the fluoroscopic image. This has resulted ny lingering and painful deaths among the men who have brought tiif apparatus to it- present efficiency. No physician ought ever to ich a reque-t . .1. Many of the injuries to physicians have come from holding the 'ope m po-iiion for testing the radiance with a fluorometer. ice -hould lie abandoned and a radiograph made of such a test I >eni i'i-t radiometer. ,) regrets very much hi- former practice of holding the Him mouth in dental radiography. The individual ex- po- in svi re ii . nefil to the patients, but their cumulative effect has permanent ly d i _ ,:<<] t lie ope rat or'- hands, and if t he pract ice had been contm iei| a c;i u'ould have been produced. ". llavinu ' - A'itche- in a different room from the .r-rav tube TIIK X-KAY 1 147 affords perfect protection. And the same object may lie attained by having t lie .r-ray t ube enveloped in a case opaque to 1 he .r-ray and having the operator stand behind a lead screen and wear leaded spectacles, cap, apron, and gloves. Repeated exposure, even at a considerable distance, to the unshielded rays from an .r-ray tube have in the case of a great many operators produced sterility and leukopenia, and has doubtless contributed to the fatal cases of .r-ray cancel'. II. Precautions in Rontgen-ray Treatment.- (A ) J'ro/cct/o/i of tlic I'dti'int.- 1. Do not give any Rontgen-ray treatment until you are able to measure and control the quality and intensity of the a'-ray and know what exposure will produce a certain effect. A single measured dose sufficient to produce a more or less severe erythema is often desirable, but is very dangerous in the hands of the inexperienced. 2. Expose only the desired portion, shielding other parts by dia- phragm or cylinders or by sheet lead or the like, fastened around the part to be treated. :>. l"se a quality of ray adapted to the case as nearly as possible all soft rays for a cutaneous lesion and all rays of greater penetration for deep lesions. The soft rays are obtained from a tube with a low degree of vacuum, and expecially with a converter producing a constant poten- tial. The rays of greater penetration may be produced by a tube with a higher degree of vacuum, especially if excited by a converter producing a constant potential. Screens, of aluminum or of sole-leather are often useful in arresting whatever soft rays may be present. 4. I'se the cross-fire system in treating a deep lesion, so that no one portion of the surface will bear the entire brunt. .">. The deeper the lesion the further the anticathode should be from the skin. If the anticathode is only 4 inches from the skin, the latter will be twice as near the anticathode as a lesion 4 inches below the sur- face, and the skin would, even if distance were the only factor, receive a radiance four times as strong as the deep lesion. The percentage ab- sorbed by tin 1 tissues overlying the deep lesion increases the difference in the effect, but is about the same whether the tube is near the surface or far from it. I). 1 )o not be deceived by the theory that any .r-radiance is so entirely made up of hard rays that it can be safely applied with the tube very near the surface and in extremely large 1 doses. Surface 1 injuries and injuries to the i issues of the intestines have followed therapeutic applications 1 >;ised upon this theory. 7. The eyes, testes, ovaries, and hair are portions to be especially protected from accidental exposure. ( J) Protect/on of the Operator in Rirntgcn-roij Tnatnimi. The same precautions are absolutely necessary as in .r-ray examinations. The Prevention of .r-Ray Dermatitis. (1) The patient should not be exposed too long, too frequently, or to too strong a radiation. The strength of the radiation depends partly upon the energy given out by the ./'-ray tub-- and partly upon the distance at \\hich it is placed, the effect diminishing as t he square of the distance increases. For instance, at twice the distance from the anticathode the region exposed is sub- mitted to only one-quarter t he st ren.ui h of ./'-ray. The length of time is, of course, dependent upon the strength of the application. For those who have not the different apparatus for measuring the strength of the application a good limit is nine minutes' exposure, at a distance of one foot from t he anticathode, and a st rengt h of .r-ray which will pen nil IMS MKIHl AL KLKCTHICITV AND RONTOKX HAYS the bones of the hand to be seen faintly at a distance of 2 feet from the anticathode. A stronger radiance 1 would call for a correspondingly shorter exposure. Sometimes in treating the side of the neck it will be found that the shoulder is much nearer the tube than the part to be t reated. and if so it would receive a dangerous amount of radiation unless shielded from the rays. In .r-ray treatment it is always desired to pro- duce some effect upon a certain area of tissue, and all other parts of the patient should be protected either by lead or other .r-ray proof sheets, or by encasing the tube in some kind of loeali/ing shield. There is some protection of the part exposed by interposing a thin metallic screen, like ihe author's screen for soft rays, or even by the clothes. Begin with smaller doses than indicated above and do not repeat them oftener than once in three days. Holzknecht's chromoradiometer furnishes a direct measure of the amount of radiation to which the region is exposed. Three Holzkneeht units applied at one session will produce a visible reaction upon the face, and this limit should not be reached in radiography. Hut in radiotherapy it will be noted that certain cases require applications of 3 or 4 Holzkneeht units, which, however, should not be repeated until the reaction has subsided. This may require an interval of three weeks or more. If the applica- tion is to be repeated once a week half the above dose is the limit, and if used more frequently a still smaller fraction of the dose is applied. A low vacuum-tube, giving a brilliant radiance, produces a much greater effect upon the superficial tissues than a tube with a high vacuum and greater penetration. The amount of radiance bears a certain relation to the strength of the current actually passing through the tube, as indicated by a milliamperemeter introduced between the coil and the tube, and it has been hoped that this one measurement would fully indicate the strength of the radiance 1 , and that we could simply apply a Mrength of so many milliamperes for such a time at such a distance. This, however, is not sufficient. A Miiller heavy target-tube, excited bv a 12-inch coil, \vitha Caldwell interrupter giving about 5000 inter- ruptions a minute, with a primary current of '.* amperes, and about 3 inches resistance in the tube, allows 1 ma. to pass. This is with con- siderable resistance in the rheostat; but with all the resistance cut out by turning the rheostat all the way, the current trough the tube iii( reases to 2', ma. and the radiance becomes much more brilliant. "We ni i\v connect t he same tube in precisely the same condition as to vacuum wuh the prime conductors of a static machine, with six revolving glass plates 2t> inches in diameter, and making about 300 revolutions a minute, the machine being in first-class working order. "We find that 1 : . i- passing through the tube, but that the radiance is not nearly as powerful as when 1 ma. was passed through the tube by the coil, ihe compari.-on is not quite a fair one that is. comparing the t of 1 ma. through the .r-ray tube in conjunction with the coil and '!,> sair:<; in coniunciion with a .Malic machine. "\\ hile it is not v known, yet it is a fact which can be easilv demonstrated, that ,a\ in- a parallel spark-irap of 1 inches on an ./'-ray coil will only : lid -park-nap of ', inch on a Matic machine. !o the use of the mill ia mpereniet ( T, Lewis Jones went lis matter very carefullv. and his conclusions were that as long parallel -pafk-^ap of the tube did not exceed ~> inches, the mim- milliampere-. through the tube irave a fair idea of its .r-rav value ; on the same a|)paratus, using the same rate of in- inches from the ant icathode during an exposure of ten minutes. (2) A screen for soft rays may be used. A thin sheet of aluminum, or of tin-foil, or a thick sheet of leather may be interposed between the .r-ray tube and the portion to be treated. The rays which produce dermatitis are those which are of little penetration and which are con- sequentlv absorbed bv the skin. A screen for soft rays will arrest these rays and allow onlv the more penetrating rays to reach the patient, and these have very much less effect in the direct ion of producing dermatitis. I'hi- protection is not absolute, however, and an overexposure is to be avoii led. (o) ( leyser has suggest ed that i he cause of dermatitis is not the .r-ray, Inn an elect rost at ic condition which may be avoided by placing the t ube directly in contact with the part to be treated. The author does not regard this as probablv correct, and recommends avoidance ot over- dosage when the Kontgen ray is applied in this way. Modern apparatus, such as the ( 'oolidge tube and the transformer and the oscilloscope, make it entirely possible to produce .r-rays cor- re-poiidiim' exactly to a specified spark length, free from inverse dis- With these factors secured, the do-aue may be accurately - so many milliampere second- with such a spark equivalent a -econdary voltage if you are sure of your voltmeter) at such ce through -ndi a filter or without any filter, i- now i I!i20 ; the method of choice. RONTGENOTHERAPY THE TREATMENT OF DISEASE BY THE .Z-RAY IT has been found by actual observation that the .r-ray has a cura- tive influence upon quite 1 a variety of morbid e-onditiems. It is not a sufficiently powerful bactericide to have any direct effect upon bacteria in doses which would be harmless to the tissues, and ye>t it is an ex- cellent remedy in myeotic skin diseases. This is due to its depilatory action and to the slight stimulation it produce's. It has a very mark- edly beneficial effee't em tubercular proevsses. probably by an alterative and stimulating e'ftect. And of a like nature is it< effect upon rheumatic 01- gouty eleposits about joints or nerves, and upon a variety of condi- tions, from colitis to keloid. It has a specific action in e'pithelioma and to some extent in every either form of malignant disease. It is a power- ful analgesic. The method e>f application is by allowing the 1 .r-ray te> shine 1 eliive-tly upon the 1 affected part from a tube 1 with a vae-uum. whie-h eh'penels tipon the depth of the lesion, and with a strength and at a distance 1 and for a length of time 1 sufficient to proeluce 1 a certain effe'ct upon the 1 tissue's. Different plans may be adopted; the' exposures may be 1 mild and iv- peated e've-ry day or e'veTy twe> e>r thive days, and a conditiem of ivae-tiem gradually reached and maintaine-el: single 1 large 1 dose's may be use'el sufficient to produce 1 the 1 degree e>f reaction required in that particular eli-ea-e. and if necessary repeated after the' three or four or more 1 we'e'ks which it takes for the' traction to de've'lop and subsiele 1 : eir half eloses may be used, each of which will e'xcite a slight traction, anel the dose's may be repeated every week or two. The method by frequently repeated small doses is the one which was at first tise-d in this country, [l would be dangerous guesswork te> apply the .?'-ray for treatment without at least measuring the spark equivalent, suppressing all inverse discharge and measuring the milliampe'rage. For doses repeated every three days the wall of the tube should be> at a di-tance of '.) inches from the nearest exposed -urface 1 . If only a small area i- to be treated the tube may be brought nearer and the time 1 peculated according to the -quare of the distance. Thus, at a distance of '> indie- from the wall of the tube or (i inche- from the anticathode or di-k fVom which the rays radiate, an exposure of 1 wo minute's and a quar- uld produce the >ame effect as nine minute- at a distance of '. t he wall of t he 1 ube or \'2 inches from t he a lit icat hode 1 . In leiuhboritlg part- -hould be protected by -heel lead or the iii a locali/iii" >hield enca-ing the tube. Thi.- is e-qually i't her the di.-t aiice be urea t or small, .r-1 tax met a I i ( 'on ley \\ . '2~>\\\ Street. New York i- very convenient for pmtec- compound '')' lead and tin, and doe- not rub ofl on the ild. The thin weight i- riuht for this purpo-e: ill- I loot \\ idi a nd co-t - 1 or t .") cent s a pound. Sheet - RONTGENOTHERAPY 1 151 of this foil, measuring 12 x IS inches, may he put over the head and face, and other sheets with a hole, which may he made larger or smaller by turning back Maps, may be applied over the region 1o be treated. Large L-shaped pieces are useful in many places, as for exposing the shoulder while protecting adjacent parts. Other opera- tors use a vertical screen of sheet lead with an adjustable orifice, and others sheet lead covered with rubber. The x-ray-proof rub- ber compound, made for gloves for protecting the operator's hands from dermatitis, makes a flexible and effective protection, but is rather expensive. With a substantial and readily adjustable x-ray tube stand, and a localizing shield which is opaque to the x-ray and almost completely surrounds the tube, the treatment of any part of the surface of the body is a very simple matter. Different diaphragms make the orifice through which the x-ray shines large or small, and vulcanite tubes are useful for introduction into the mouth or vagina. Treatment tubes of various patterns have been designed by Cossar, of London, and Morton, Cleaves, and Caldwell, of Xew York, and by the author. In one type the bulb is large enough to avoid overheating and rapid change in vacuum, but is made of lead glass opaque to the .r-ray while transparent to ordinary light. Opposite 1 the anticathode there is a prolongation through which the .r-ray passes, the extremity being made of glass which is transparent to the x-ray. There is a glass handle, bv which the tube may be held in position for applying the .r-ray to some small area like an epithelioma near the eye, or the prolongation may be passed into the vagina or mouth for the treatment of a cancer of the uterus or of the tonsil. In any case it is desirable to slip on a rubber cover, which is used only for a single patient. In another type of treatment tube the bulb and prolongation are similar to those in the one just described, but there is no anticathode. The concave cathode directs the cathodal stream into the prolongation, and when this stream strikes the glass Avail of the prolongation the x-ray is produced. Such a tube may be successfully used in the rectum, but, of course, the prolongation must be kept cool by a constant flow of water through an outer jacket. Still another type has the anticathode near the end of the pro- longation, directing the x-ray laterally, and, because of its close prox- imity to the glass, blackening the active part of the tube very quickly, Such a tube mav have a heavily insulated wire returning from the posi- tive pole or there may be no wire there. In the latter case the coil must not be a too powerful one and the positive pole of the coil is some- times grounded. This tvpe of tube is less desirable than the others. A fourth type is the unipolar x-ray tube, constructed on much the same lines as the last described, without a positive wire. The cathode is connected with an Oudin resonator. The high-frequency and high- tension current produces a cathodal stream which impinges upon the anticathode and is then converted into the x-ray. These are made in small sixes for use in the mouth and get overheated if run for more than about half a minute at a tune. As the anticathode is so near the surface to be treated, one or two short applications are enough. This tube, of course, acts also as a u'la or even o ampere- i- ample. The author greatly prefers a mechanical inter- rupter, such as the Wappler wheel interrupter, for radiotherapy. Six amperes would be the current furnished by a Wehnelt interrupter in which only the tip of the platinum is exposed, and this is 1 milli- meter in diameter, no resistance being interposed by the rheostat. A ('aldwell or Simon's interrupter may have small or comparatively large holes between the two portions of liquid, or. in some cases, the -ixe of the opening is adjustable. If the openings are small the in- terruptions are rapid and the strength of the primary current is per- haps only from 3 to ."> amperes without any rheostat, but the second- ary current, as indicated by ( laift'e's milliamperemeter and by the .r-ray, produced will be very good indeed. With larger holes the interruptions are -lower, the noise produced is of a lower pitch, and the primary cur- rent may be as much as 10 or 12 amperes if no rheostat is used. This produces a brilliant .r-ray and a much stronger secondary current than with the smaller and more rapid interruptions. Hut this strength is usually cut down by the rheostat until the secondary current and the ./-ray are about the same as those with the more rapid interruptions. The primary current in this case remains quite heavy, perhaps S or 9 ampere-. With a coil the greatest amount of self-induction in the primary winding i- desirable for treatments. For several treatments in rapid succes-ion it will be found necessary to have at least two tubes in readiness. The anticat hode gets very hot from continuous use, gives out an injurious amount of radiant heat, and throws off metallic particles which blacken the tube. The gas-filled, water-cooled tube runs for a long time without a change in its degree of vacuum with the strength of current -uital >le for treatment . The important measurements in treatment are the quality and the amount of ./'-rav. The first must be determined partly by means of the spint remeter, showing the length of spark which will pass between the pole- of the ./'-ray generator rather than pass through the tube. The hiirher the degree of vacuum in a gas-tilled tube, the greater is its resistance to the pa--aue of the current and the longer is the spark it will back up. Another method of determining the quality is by noting with the lluoro-cope the degree of penetration of the ./'-ray produced. excee - oW to make a pract ice of 1< Miking at d. although th< se of a radiometer in which the decree of et al thn High which the ./'-ray er's and I>enoi-l's radiom- penet rat loll. i lie mea appneo may i >e by Sabouraild and Noire s - chromoradiomet er ID. I 1 ."> 1 . which RONTGENOTHERAPY ] 15.'] responding to a certain number on a color scale. To give the same treatment recommended by some authority it is only necessary to u.-e the same resistance and to continue 1 the application until 1 he prescribed nnmlier of Ilol/knecht unit- have been applied. Thi.- doe- not mean that it is necessary to use one of these pastils every time the .r-iav i- applied, or even that it is absolutely necessary for everyone u.-ing the .r-ray to have the Ilolzknecht's chromoradiometer, but it is very desirable that everyone should know the strength of his apparatus in term- of these international units. Thus, one >hould know how many minutes' exposure it takes to equal *> Holzknecht unit- with such a tube and vacuum, and -uch a primary winding, and such an adjustment oi the rheostat and interrupter, and with or without spark- gaps and at such a distance from the anticathode to the surface treated, and with .-uch readings ot the amperemeter on the primary circuit and the miliiamperenieter on the wire pa>-ing from the coil to the .T-ray tube and with such a spark equivalent. The efficiency of dif- ferent tubes, coils, interrupters, transformers, and static machines u-ed to vary so much that the strength of the application could not be stated accurately in ampere- or milliamperes. The ( 'oolidge tube and the u'eiierators made to excite it have made it possible to state the ap- plication as of -uch a number of inches back-up and such a number of milliamperes, and with these generators the same technic may be used with a uas-filled tube. ( tne may begin with the dose indicated on p. 1 1 17, and gradually acquire a knowledge of safe and effective dosage, or one may watch the work of an expert long enough to be able to rec- oirni/e the different qualities and intensities and to know their dosage: or. better -till, one may have the different instruments of precision, and thu- be able to more accurately duplicate the applications recommended by workers in different part- of the world. Attention to detail i- absolutely e.-sential in .r-ray work, and the operator should record every condition under which each exposure to the .r-ray was made. THE TECHNIC OF RONTGEN THERAPY An >>- or 12-inch coil may lie u>ed. and its primary winding should be -uch a- to give a variable -elf-induction, and u-ually the greatest amount of -elf-induction i- used. The details of this and other technical point- are more fullv u'one into in the section on Radiographie Technic. A YVehnelt interrupter with a platinum rod 1 mm. in diameter and with ju-t it- tip exposed, or a mechanical wheel interrupter, or a Caldwell- Simon interrupter with comparatively >mall holes will be found to give the be-t eurrent. This should have rapid interruption- and a strength of '_' to 1 or ") ampere- when properly regulated by the u.-e ot t lie rheostat. A transformer with high-ten -ion rectifier or an unfluctuating current gen- erator may be used, but with a much weaker current than for radiog- raphy. The-e are preferable to an induction coil. The intensity of the .r-ray it-<'lf -hoiild be measured with a certain ,-trenuth of eunent. It \\ill be easy to duplicate the condition- at any time. The Standard ('oolidge tube with a -olid tumi.-ten anticathode simplifies the technic very much, or, among gas-filled t ube-. a wat er-co< >led t ube i- excellent, 7- inch t uni!>t en t aru'et t ube or wa t er-c< >oled 1 ube ; Fig. 1S7 ] are very >at is- t'actory. It ha- often been stated that the vacuum should be medium or low. resistance 1 or 2 inches, and radiometer '2 to 1 Heiioi-t for an effect upon the -kin: but the author believe- thai for the be-t result- in skin 1154 MEDICAL ELECTRICITY AND RONTGEN RAYS lesions as well as for deep therapy a back-up of 6 inches is required. The current passing through the tube itself should be 1 to 3 ma. Spark-gaps between the coil and tube are usually not required, but should be used if the tube shows signs of inverse discharge, especially by an oscilloscope or by the absence of a sharp equatorial line dividing the light from the dark hemisphere. (The two positive terminals are connected by a wire, or only the anode or the anticathode may be used to get the best ra- diance.) The tube should be so placed that its long axis is parallel to the surface to be treated; the wires are in this way as far as possible from the patient. The radiance is equally intense in practically all directions in front of the anticathode. The neighboring parts should be protected by the Ripperger, Fried- lander, or a lead glass shield, or by sheets of x-ray metal, or by the use of .r-ray tubes made of lead glass opaque to the x-ray except in the direc- tion of the part to be treated. A stand should be used substantial enough to stand the weight of the tube and shield, and with arrangements by which the tube may be readily adjusted in any position. Such a one is Ripperger's, slightly modified by the present author. The Dosage of the x-Ray. This is a matter which is influenced by various considerations which produce the greatest possible difference in the intensity of the radiation from different apparatus and from the same apparatus differently manipulated. Two entirely different methods of administration are in use. In one, one-sixth erythema doses are given at intervals of three days until a reaction of the desired degree is gradually produced. The operator must not guess at the above dose, but must know how to measure it. A good example of this fractional dose is (i-inch spark, 3 milliarnperes; 10-inch distance, 3 mm. aluminum filter for two minutes. The other method requires a knowledge of the dose which will produce the necessary reaction with a single application. The dose in the second met hod is equally easy to define, but requires a special apparatus for its measurement or very great experience and judgment in applying the .r-ray. One special apparatus is Holzknecht's chromoradiometer. A chemically prepared pastil is exposed at half the distance from the tube to the part under treatment, and the ap- plication is continued until the pastil has changed color to corre- spond with 1, 2, o, 4, or possiblv "> of the color scale. This indicates thai the irradiation ha- amounted to a corresponding number of IIolx- knecht units. One II. is about a third of the amount of t lie .r-ray that uiu-t lie applied at one -e-sion in order to produce a visible reaction on the face; M or 1 II. i- a full dose, and would not be repeated until the reaction had developed and subsided, usually not for several weeks; ") II. with 1-inch resistance is a verv large dose, sometimes required in cancer cases; 2 II. is a half dose, which may be repealed every two weeks and will maintain a con-taut moderate reaction. In every case it is nece-~ary that the tube should be of the propel' degree of resistance, although Ilolxknecht thought originally that a certain number of units fe(| liv hi- instrument would product' the same effect, whether -i-1ance were high or low. This has not proved to be the case, ipparatu- doe- mea-ure the amount. The I lol/knecht (II) it. but without the chromoradiometer this would require which the distance and duration of exposure would be and the intensity of the irradiation would be the most RONTGENOTHERAPY 1155 complex, factor. The latter, of course, is determined by the spark equivalent and the milliamporagc. For this measurement of the Holzknecht unit see page 11(>8. llolzknccht Unit* tit Sic in Distance. McKee so measures his dosage, and a discoloration of 1 II would be equal to 4 H if the pastil were at the usual one-half skin distance. daiffe'x Mcdxurcnicnt of .r-h'tii/ DOMUJC.* His method employs a piece of barium platinocvanid screen, which is placed upon the surface of the body near the part under treatment. A part of the screen is shielded from the .r-ray by different thicknesses of some such material as lead- toil. The general surface soon loses 1'ts brilliancy of tluorescence, while the parts which are shielded do so more slowly. The latter, however, is only a matter of time. The unshielded part undergoes a maximum loss of brilliancy which is attained by the different shaded portions in succession. To see what amount of .r-ray has been applied the barium platinocvanid screen is removed from behind the shield and held up to 1 i-. s().s the .r-ray. Some 1 parts of the shaded portion mav be found to have exactly the same loss of brilliancy as the unshaded portion; the number of pails which have attained the maximum loss of brilliancy shows the amount of .r-ray applied. Such an apparatus should be standardized so thai each unit would be equal to 1 llolxknecht unit or a certain frac- t ion thereof. Scl< nhnti ('<) MKDICAL KLKCTHICITY AND KONTCKX KAYS resistance, and inilliamperemoter may bo al a distant position, whore the operator may be protected from the .r-ray by the interposition of a brick wall it' this is desired. Any change in the amount of current registered bv the niillianiperenieter would, of course, indicate a fluctua- tion in the amount of ./'-ray being generated by the lube, ami would cause the operator to take the necessary steps to regulate the tube. The use of the apparatus as a measurement of dosage is more or less; empiric. The selenium cell is set at a certain di-'ancc from the .r-ray tube and the amount of deviation produced in the milliamporemeter is noted. A Sabouraud and Noire tablet for radiomet ry or a Holxknooht tablet is exposed for the time necessary to produce a specified number of Hol/kneeht units. This furnishes a scale from which the operator can judge of the number of units or fraction-; of units applied in any number of minutes. It is necessary to place the selenium cell at the same distance as in determining the standard, and to regulate the in- tensity of the .r-ray so that it will produce the standard deviation in the milliamporemeter, and then expose the patient for the necessary num- ber of minute- to produce the required dosage. Boi'il/t /'.< I 'nit I. It is the amount of .r-ray which, acting upon a 2 per rent, solution of iodoform in chloroform, the rays being normal to the surface -the surface being 1 square centimeter and the depth 1 centimeter- will liberate ,',, milligram of iodin. '.->.') I is about equal to 5 II. 1 5 Holxknecht unit-;. I>nri>r'lifjh/>foni('tr>c Miffioil. -This consist s in a method i*- 1 ' I he illumination produced in a barium platinocyanid creei it of ordinary light of different candle-powers. \Jiilmil nf It/nliti/t/i ////. This i- in (leiermine by \'olume the anio r.' alomel precipitated from a solution of ammonium oxa- late and 'hloi'iil wheti exposed to the .r-ray. EtOXTOEXOTHERAPY 1 1 ")/ Caxtex modifies Schwartz's method by taking the weight 'of the pre- cipitate instead of its volume. Cnrchod's Method of x-/\'(ty Dosage by a Voltameter rti the Secondary Circuit. 1 The instrument is like a pipet containing 15 cc., but with its lower end bent up so as to hold about 10 cc. The latter is open at the top. .Platinum wires allow the secondary current to pass through the acidulated water in the closed arm of the pipet, and bubbles of mixed hydrogen and oxygen gas tire liberated and accumulate at the top. The number of cubic millimeters of gas liberated while a Sabou- raud and Xoire barium plat inocyanid pastil is changed to tint B affords a unit which may be subdivided at will for future treatments without having to use 1 the pastil each time, and it is useful by giving smaller fractions than the Sabouraud and \oire method. liiraonu's Aelinomcicr. This is an instrument for measuring the intensity, in actinic rays, of the various lights used in phototherapy and also of the x-ray. A hollow metal cylinder has an opening at OIK; end which fits closely over the observer's eye and at the other end a disk half of which is opaque and black, the other half being coated with barium platinocyanid. This end of the tube is closed by a sheet of quart/ crystal, and the whole tube is moved back and forth by means of a rack and pinion in the dark box which surrounds it. This box is filled with a solution consisting of: Opposite the end of the tube there is a quartz window 4 cm. in di- ameter. The light to be tested passes through this window, through the liquid, and through the quart/ window at The end of the tube, and produces a greater or less fluorescence in the barium platinocyanid at that point. The solution with which the box is filled absorbs the actinic rays, and if the layer of liquid is thick enough it will entirely prevent the visible fluorescence of the barium platinocyanid. In apply- ing the test the actinometer is held at a distance of 2 meters from the source of light, and the tube is moved back and forth in the box so as to measure the thickness of liquid required to suppress the fluorescence. Tested in this way an arc light for phototherapy (current of 110 volts. 20 amperes) suffered absorption of all its actinic rays by 5X.5 mm. of the solution; a large arc lamp for stereopticon purposes with vertical carbons (110 volts, 20 amperes), by 55.5 mm.; a small arc lamp for the stereopticon (110 volts, 7 amperes), by 42.5 mm.; the direct rays of the sun at 4:^0 p. M. in July, by 70.5 mm. This method is applicable to all varieties of phototherapy, including the ultraviolet ray from (leissler tubes. It has not yet been deter- mined whether this furnishes a reliable guide to the comparative in- tensity of the .r-ray, but it certainly seems less convenient than the ordinary radiometer dependent upon the thickness of a metal which the .r-ray will penet rate. This is indicated upon a barium platinocyanid screen or upon a photographic plate in the cases in which it is desired to produce an indisputable record of the 1 penetrating quality of the ray employed in making a radiograph.- 1 Arch. d'Hlec'tric-ito Mc'liralc, Jan. 10. 1907. - Ihi-L. Bordeaux, France, Jan. 1.1, UK):]. 1158 MEDICAL ELECTRICITY AND RONTGEN RAYS Kienbock'x Qtiantitometer for Measuring x-Ray Doxage. The appa- ratus used by this Vienna radiologist 1 employs little .slips of not very sensitive bromid paper of a standard make. One of these is wrapped in black paper and exposed at the same time and distance as the patient; then it is placed in a developing solution of standard strength for a standard time (one minute) inside a little portable dark room. The developed paper is at once compared with a scale of different shades of paper. The number marked on the shade which the test paper matches indicates the number of Kienbock units applied. Kach unit is called "x." and is equal to A 11.. so that this method is twice as delicate as the Hnl/knecht method. The developing-box is just large enough for the hands to work inside of. a dark sleeve being fastened around the wrist to exclude ordinary light. Kuby glass windows admit red light and allow the operator to see what lie is doing. Possible sources of error are a change in the sensitiveness of the paper from age or atmospheric conditions and a change in the activity of the developing solution. Milton Franklin $ electroscope for the dosage of the x-ray consists of a delicate electroscope, which may be placed at a measured distance from the tube. The electroscope is first charged and the rapidity of discharge is noted by means of a magnifying glass. A circular metal disk forms a shield for the operator. The labour and and Xoire Radiometer. This is described more fully on p. 1181. A little tablet coated with barium platinocyanid is exposed at half the distance from the anticathode to the surface to be treated during the x-ray application. When the original apple-green color has changed to tint B, a brownish yellow, a full dose of 5| Holzknecht's units has been applied. The Hampson radiometer has a colored scale of 25 tints with which an exposed barium platinocyanid pastil is compared, 4 E at skin distance equals Sabouraud tint B or about 5 H (Holzkneeht units.) The Lovibond-Corbett tintometer is a device for accurately estimat- ing the coloration of a Sabouraud and Noire pastil. It has been stated- that doubling tiie voltage (without changing the amperage) results in only doubling a Holzkneeht pastil reaction, while it quadruples the photographic effect. Within certain limits this is ap- proximately correct; and the effect upon the skin is only doubled while the deep effect is quadrupled. With the doubled voltage the x-rays possess four times more energy and are more penetrating and less ab- sorbable. The effects of all kinds are proportional to the energy of the ray- reaching 1 he specified object and to t he quantity of energy absorbed by t he object . I/are/'* Carrii-r for the Sabouraud and Xn/rt [Radiometer* This ap- paratus (Fig. 810) is employed by the author and is made of hard rub- ber and i- damped to the x-ray tube near the cathode. It carries one of the Sabouraud and Xoire tablets, which may be adjusted at half the di-tance from the aiitieathode to the patient, and also a dark brownish- yellow tablet for comparison. During the exposure the radiometer tablet i- protected from ordinary light by a sheet of black paper, but occasionally the tablet may be turned back for comparison with the 1 I.' ll'i'l.-im. April. I'HMl. p. 1'J.I. -Am'T. Jour. Klcrt rotlicrapriitics jind Radiology, vol. xxxvi, No. 1, Jan., 101S, p. :;i. 3 Arch. il'Klc.-trintc M<.,lic;i!c, Jan. 10, 190.1 RONTGENOTHERAPY 1159 tost object. When it has turned the same dark yellow color as the latter it is called tint II, which means that a full therapeutic dose has been applied, causing all the hair of the scalp to fall out from a single treat- ment. This is equal to f^ Ilolzknecht units. It is supposed to be necessary only to simply continue the exposure to the x-ray until the test object has undergone the standard chemic change as indicated by its color. Practically, it is found that a variety of conditions, atmospheric and otherwise, render it difficult to apply these methods every time the x-ray is turned on. At the same 1 time, these methods, applied under ideal laboratory conditions, are excellent for use in standardizing other more 1 practicable methods of dosage. The practical object to be sought is a means of measuring the in- tensity of the radiation in terms from which one may in an instant calculate the duration of exposure at a given distance required to Fi. SlO. Haret's carrier for the Sabouraud and Xoirc radiometer. produce a certain effect on the tissues if rays of a certain quality are employed. x-Ray Doxayc. For Rontgen therapy as well as for radiography an entirely satisfactory and universally available method is to regulate the apparatus so that it will apply rays corresponding to a certain spark length or resistance or voltage and a certain milliampcrage, either through a certain filter or not, for a certain length of time and at a cer- tain distance. With the Coolidge tube and a modern transformer outfit these factors are easily controlled. Any operator's determination of the factors required to produce a certain physiologic effect may be by reading authoritative statements as to dosage, and in this case it is most important to be sure that one's technic is correct, especially as to the voltage or spark-gap represented. Or the individual operator may test the dosage himself by keeping accurate records of the factors employed in each application and of the results therefrom. This method usually requires some 1 approximate 1160 MEDICAL ELKC'TRK'ITY AND RONTGEN RAYS guide in the beginning cither from the experience of others or from some direct method of measurement of the radiation itself. Or the operator may adjust his apparatus for the desirable factors of voltage or spark and milliamperage. and then by means of an ionization chamber or of barium platinocyanid pastils or of photographic paper determine the time required to produce a Sabouraud or Kicnbock or similar unit of .r-ray dosage. It would be wise to make such a determination re- peatedly to overcome sources of error and finally to use the electric and time and distance factors for actual treatments. These are more uniformly reproducible than any dose involving the direct measurement of the radiation for each treatment. With modern apparatus the author's unit of the intensity of the .r-ray is no longer required. Kxample of erythema dose of hard .r-ray s: In treating a recurrent malignant tumor of the intestine the author used a 3 mm. aluminum filter and the anticathode was 10 inches from the skin. His generator of a con-taut high voltage was used with a parallel spark resistance of ~)'l inches and the current was 3 ma. Each exposure was ten minutes for successive quadrants of the abdomen, shielding the others with lead about \ inch thick. The same 1 area was exposed at intervals of three weeks and the second exposure was followed by transitory sensation with scarcely any change in the appearance of the skin. This is exactly the author's teclmic for deep therapy when the same area is to be exposed at intervals of three weeks or more. He makes the time possibly 50 per cent, longer when only one ap- plication is to be made to the same area. T<>ux(-ii r/a'/N <>f .I'-h'iti/ Power and Quantity. 1 Touxcu is the .r-ray power which will produce upon kodak photographic film an effect equal to that of 1 candle-power of carbon filament incandescent electric light of the usual brightness, applied for the same time and at the same dis- tance. Different films and plates present different ratios of sensitive- ne-s to light and the .r-ray. Kodak film is selected because universally obtainable. It is equal to 0-inch spark and .10 ma., or to 6-inch spark and 100 ma., or 4-inch spark and 200 ma. 1 TUHXCII uictcr xccond is the quantity of the .r-ray which will produce upon kodak photographic film an effect equal to that of 1 candle-power of carbon filament incandescent electric light applied for one second at a di.-taiice of 1 meter. ition = 1 II. it ion = ">.\ II. ition : Tint B. Sabouraud and NoirtS. ition Tint 1 Bordicr. ition - '.'> or -1 units I Bordicr- ( ialinmrd. ition (i2. r ) Ciuilh'ininot units. M. it ion 10 X i Kionbock), it ion '>.."> kalonis (Srli\vart / ' . ition An ordmarv crvthcina RONTGENOTHERAPY 1101 This is a valuable means of gauging the intensity of the .r-nty, and so determining its safety limit and the exposure required to make a pic- ture in radiography and its dosage in therapeutics. . 1 ji/>l/c(itioti of ////N Mdhoil l<> Secure Nc//r/// /// Radiotfra [thij. The radiographer should measure the intensity of the radiance which he habitually uses for certain classes of work. If this is of 1 Tousey power, then .")()() meter seconds (or fifty-five seconds at ] meter from the anti- cathode to the skin) would lie an erythema dose. This exposure at one time, or divided among several radiographs within a week or two, would DR.S.TOUSEY produce an .r-ray burn. If one's technic is so poor or the subject so diffi- cult that the examination cannot be completed without approaching this s.-ifcty limit, the attempt should be abandoned. .(-Rav of 1 Toiisev power will make most radiographs in a fraction of a second with or without an intensifying screen, depending upon the i lifficulty of the case, 77" THII.^I i/ Mi t/inil nf l)dsii'i< >n L'ii/ifi!< not/it rn />>/.- For surface lesions no tilterinu' sci'een is used eith.er for previously measuring the Tousey pow< r with a kodak film or during the treatment. If the .c-radiance lias 1102 MEDICAL ELECTRICITY AND RONTGEN RAYS Erythema Exposures vf x- liny of Various Rndiographic Strengths. Antieathuile to Skin. Meters. Inches. 13 56 6 ''- 1 ' 14 ' 13 2 4 i til 42 13 52 1 64 14 | 13 <)j 6 til 2 ' 1 3 13 18! * G " 4, an erythema dose of 500 Tousey meter seconds. Other distances and their erythema doses are given in the following table: Erythema l)nx< of x-Rny in Ordinary Therapeutic Strength. I H-tanfe fro tO r 11 antirathtxle kin. '1'ousey power. Six-inch spark. Ma. Four-inch spark, Ma. Minutes. Meters. Inehw. 13 1 /()() 14 3 56 - 13 1 50 2 4 47 13 1/40 21 5 37 13 1/30 34 6| 28 9 3 1 /'()() 14 3 31 94 1/50 2 4 25 94 1/40 21 5 20 9! 1/30 3f 6 15 8 1/60 14 3 20 s 1 /50 2 4 16! s 1 40 2. I 5 134 i 8 1 /30 3 , 61 10 i 6| T>0 u 14 ji 6J 50 111 i til 40 94 i til 30 7 i 5 i IK) 10 i 51 50 S| i 5.1 10 61 i 5.1 /30 5 i 4; /tiO 8 4; /50 61 i 4; 1 10 54 i 4; 1 :!() 4 i I 1 , 1 tiO 6 i 1 1 1 50 5 ! { 1 10 4 : 45 1 30 3 1'nu.i,, 1'nii-i r of thi .r-lttii/ front \' ampere- ,-ind a -ecoTidary current of 11 ma., produces an x-ray of about ,.',, ToU-e\'. RONTGENOTHERAPY 1163 ~ o O i c - *T: T. ~ ~ "' w 5-5 ~~ - "^ i'>.H.^= ^ t. X t_ Ilti4 MEDICAL ELECTRKTTY AXD RONTCJEX KAYS The same coil, with a Wchnolt interrupter and a primary current of 110 volts and IS amperes and a secondary current of S ma., produces an .r-ray of about ^ Tousey. A static' machine actuated by a current of 220 volts and 25 amperes and sending about ('>] ma. through the .r-ray tube produces an .r-ray of about i Tousey power. An interrupterless transfonner or a high-tension direct current gene- rator produce from ,1 to 1 Tousey for radiographic work, and may be reduced to ,;',, Tousey for treatment or Huoroscopy. Modern apparatus, such as the Coolidge tube and the transformer and the oscilloscope, make 1 it entirely ]>ossible to produce rays corres- ponding exactly to a specified spark length and milliamperage free from inverse discharge. And with these factors secured the dosage may be accurately stated as so many milliampere seconds with such -park equivalent (or such a voltage if you are sure of your voltmeter), at such a distance and with or without such a filter. This is now (1920) the method of choice. ViUdril'* Instruments for Measuring the Intensity and Quality of the x-R::. or. like Johnston's, upon the resistance of a selenium cell. '.'M methods and several others might give different results types of apparatus .-ending impulses through the .r-ray ; i ! rat es per minute. the .''//> imirhhn for ./'-ray treat merits is entirely satis- H ' m;i'-hine is powerful enough and in good working order. Arch. d'Klcctriciti' Mrdic;de, .Ian. 10, 1907. RONTGENOTHERAPY 1 l()f> Measured by ;i milliamperemeter the current passing through the lube will be found not to be much over 1 or '2 ma. at the most, ami the fact that tlie amperage is very lo\v makes the healing of the ant icathode very slight. In fact, 1 he heat is dissipated as last as it is produced, and so the bulb may be used for hours without getting' hot and without material change in decree of vacuum. Jt is on this account that tin- less expensive?, but equally well made, light anlicathode tube- are used with t he stat ic machine. The small amount of current passing through the tube causes the intensity of the ray to be so slight that much longer exposures are required than with a coil. Jvxperience in radiograph v Allows thai t he 1 in ie must be about five t nnes as long, and in fluoroscopv the safe t ime of exposure is so long 1 hat t here is danger of forget t ing 1 hat t here i< a limit beyond which 1 here is the risk of a burn. In radio! herapy with the static machine, in the absence of special apparatus, like Ilol/- knecht's chromoradiometer, the dose which may be administered every two oi 1 three days may be Mated to be eight to lifleen minutes at a dis- tance of 10 inches from the anticathode. This is with a machine having twelve or sixteen revolving glass or mica plates, i>'2 inches in diameter, and with a t ube of medium or hi.irh vacuum, backing up a spark of .'! to o' inches. Spark-gaps are generally useful when working with a -tatic machine. THE -V-RAY IN THE TREATMENT OF MALIGNANT DISEASE 'I he ./--ray most assuredly has a selective action upon the atypic, rapidly developing cells which constitute the essential part of most malignant neoplasms. There is reason to believe that tne soft rays. those with the least penetrating power, produce the most beneficial . and it is very certain that the disease-, like epithclionui. in which the lesion is ofien a purely surface one. an 1 much more amenable to this method of treatment than are the carcinomata and the sarcomata with deep-seated lesions. Still, even these are almost always favorably a !'ii rted. and in some case- a cure may be produced. The effect generally .-ought is not one of destruction < n tndxxc, but of molecular change and elimination. It is seldom wise to produce an ulceration by the applica- tion of i he ./'-ray in treating malignant disease. In some cases the elimination of the products of a degenerative process produced by ./-ra v t reat men! of a large malignant growth will cause 1 a .-ort ol toxemia. This is a temporary mat ter and its nai ure is discussed in the chapter on the phvsiologic effects of the .r-ray. It mav furnish an indication for less vigorous treatment for a tune; it doe- not indicate a tendency on [lie part of the treatment to produce metastases and a general dissemination of the disease. The latter question has been most thor- oughly studied. In certain cases which are submitted to .r-ray treat- ment while the disease is still purely local, and before any metastases have taken place, the x-ray effects either an actual or a symptomatu cure. In other cases metaslase- have already occurred and may some- time- be demonst rated by .r-ray examination m the mediastinal glands, although symptoniatically the disease may still appear to be a local one. In such a case .r-ray treatment ma\ produce a brilliant effect upon tin li sion, and this mav be accompanied by a most gratifying increase in health and strength. Then after a period of. it may be, seemingly perfect health lasting for several months, the patient shows evidence llOt) MEDICAL ELECTRICITY AND RONTGEN RAYS of the systemic involvement, and a fatal termination very quickly ensues. In such cases the .r-ray has not caused the dissemination of the disease, it has simply been unable to prevent it. Much benefit may be accom- plished in such cases in the direction of removing, controlling, or pre- venting the' recurrence of a local lesion and delaying the occurrence of metastases and death, and. except for intrathoracic and intra-abdominal cancers, a considerable percentage' of cures may be expected. A'-ray treatment before and after an operation upon an external growth, such as a carcinoma or sarcoma of the breast, has a decided tendency to pre- vent recurrence. The same holds good of cancers of the neck of the uterus, a part which can be reached directly by the .r-ray, but here internal involvement has practically always occurred before .r-ray treatment is begun. Valuable and effective as it is in these cases it will probably not save the patient's life. The beneficial effects of the .r-ray in cancer are the relief of pain by an immediate action, the cure or control of a local lesion, a directly beneficial effect upon the general health, the prevention of recurrence if internal involvement is not al- ready present, and the cure or control of external glandular metastases. A'-ray treatment is indicated at every stage of a cancer, but it should be an adjunct to and not a substitute for surgery in the majority of cases. The technic consists in exposing not only the affected region, but a considerable surrounding area, to the rays from a tube with a low vacuum ('resistance 3 inches) or preferably a high vacuum for surface lesions, and a high vacuum (resistance inches) for those more deeply seated. It is absolutely necessary to produce a certain degree of reaction, but probablythe best results are obtained when this occasions only redness and a dry desquamation without uleeration. Cases of deep-seated cancer, as of the breast, in which the disease has not produced uleeration, are as amenable to the influence of the .r-ray as cases in which uleeration has occurred. The same two methods are available for cancer that are used f or other cases. By one method moderate doses (nine minutes at 10 inches from theanticathode, with an intensity which shows the bones of the hand faintly at 2 feet; or \Vehnelt interrupter with tip of platinum I mm. in diameter exposed, primary current 1 amperes, current through .r-ray tube 1 or 2 ma., six minutes at a distance of 10 inches from the anti- 'athode; or static machine with twelve revolving plates '.]() inches in diameter, ten minutes at a distance of 10 inches from the anlicathode) are iriven about every three days. Or, preferably, li-inch spark, 10-inch di-t a i ice, 12( ' m ill iampere seconds without a filter or 210 m. s. with o mm. aluminum. The development of the desired reaction is gradual and the dosm'e mav be regulated accordingly. Treatment is usually continued for a li'iod many months, possibly making complete intermissions from The other method involves the administering, either at a If doses, of a sufficient amount of .r- radial ion to produce leuree () f reaction. The amount is m terms of IIol/- oradiometer, and i- 1 II., > H., or even more in certain But the working direction- are about (100 ma. seconds at 10 with a li-inch -park and no filter. Or 1200 ma. seconds with :> it aluminum. The application should not be repeated until after velopmeiit and subsidence of the reaction. This will take from to MX weeks. _\ standard Coolidge tube or a water-cooled or ded ua--tiiled lube are excellent for this purpose. A locali/ing RONTGENOTHERAPY 1167 shield is a desirable means of protection for the operator and the patient in the treatment of most cases. With some apparatus a primary current of 2 or 3 amperes and 12 volts is suitable for therapeutic work, while, with others a primary current of from o to 10 amperes and from (>() to 90 volts is required. The different elements that go to produce the x-ray are so complex and mutually dependent that the only universal measure of efficiency and dosage is in the radiance itself. The number of milliamperes actually passing through the tube furnishes a guide of considerable value, though it does not dispense with Hie other considerations. About 3 ma. passing through a tube with a resistance of (> inches usually produces at a distance of 10 inches a normal dose of ', II in one minute. This normal dose is the radiation which may be repeated every two or three days until a reaction gradually becomes established. d'kin will stand. But this does not mean a greater number of millianipere seconds. Ordinarily for dee]) radiotherapy a filter >uch as o mm. of aluminum is ii>ed t<> shield the skin from rays which could not penetrate the su- perficial tissues and affect the deep tissues, but would be useless and dangerous. The dose in II units is always after the rays have passed through the filter and can u>ually be larger than the safe dose of unfil- tered r-rays. The author's generator was devised to produce approx- imately homogeneous .r-ravs and to avoid the necessity for a filter. 1168 MKIHCAL Kl.KCTKiriTY AND KONTCKX HAY Kxposrm: TABI.I: FOR ROXTOKX-RAY THKIIAPY Introiliic!i>ry. l'i\v II or ;m "erythema do]iark-i:ap of ~) inchi'.- or less, or to (1 Brnoist or lc. will produce an rrythcina of tlir skill. If a filter i- u-ed the ijiiantity which reache> the >kiu i- niea-ui-ed. not the total of \\hat is arreMed li\ the filter and what p:ts>es throimh. Hard ray<, tlnmmh a thick lilter. can lie applied in much greater iiuantity than the "erxt'iiMiia dose" without producing an erythema of the skin and with much invater Item-tit to deep Ic-ioiis. \'ery u'l-eat cMiitu-mn ha> an>en in reuard to t he Holx.knecht unit. Some oper- ators measure the discoloration of the barium plat inoryaii id | laMil "at skin (list aiu'e," or at the same distance a> the >k in. One 11 mea-mvd "al -kin distance" i- an ery- t lieina dose equal to four 11 with t he past il at one-half the di-1 ance to the skm. The latter i- ihe original method and i.- adhered to in the present volume. s 9 lit I'nless otherwise >tated the do-e- ^iven hely a'i inexperienceil < iperali ir. Tin vohauc and -park and milliamjiei'e- ;q'e tlii' lie-t iiuide. providing (lie cur- rent -full\ rec'i Hied. If there i- inver-e di-chariie tl i HJMTCS are daiifierously mi-Ii-adiim'. The -tamlard ( 'oolidjje tuhe and a rectiiied trail-former ai'e excellent i iplying t lie-e di es. Id HI I 1 1 l-'i >r animal experiment- >timu!ate- lymphat- ics and llicri'::-e- lympliocytes in the hloo'd. Ill IKi'.) Spark, 7 3 10 30 10 Id in Kl'Vt lieilia do.-l 10 i5' '10 Author'.- do-c l'(.r every kind n|' therapy. .\l VIT C.MIl.-O derilKI- i it is. Not to he re- peated in-idr ot' t'olir tn >i\ weeks. tcriK- iifci >i.\ areas. I )ivi(ied into 1 1m e >uc- cessive da>> l'i }' each area. Always prom >unced n- ^ Iti action. tn to Kxtivnir (ltP. Deep 12 2-1 and indurated cpi- t hrlioina. 'I' 1170 MKDICAL KLKCTKICITY AND KOXTC.EN HAYS EXPOSCKE TAHLE V( >H RONTC.EX-RA Y THERAPY X '. ''! ."> 7i) :r>( i 10 3 si '.'. ."> VI) 100 10 '1 9 in 10 [) 10 - 10 9 in 6 10 9 in i9j . . 3 !.< except to render tliem more Hl-cepible to being killed b v :;c,' r. KOXTCKXOTHK11APY 1171 Spark, niches. Benoist Bauer. Ma. Min. Ma. min- UteK. I >].-- Kilter nun. of 1 1 Ji = 2 \ ' tain-e, aluminum un- indies. le.ss stated. II 1 X It) (IS) 2 (l()j | IS .") and 1 rum. -10 SO F. Winter. 1 brass 1'terine fibroma each of two ti-inch areas; lower abdomen, two of back. Protect 1-inch strip median line. These four applications in two days at end of menstruation. Cause amenorrhea at once. Measure SO x by ion- tophoresis. One of his cases had dermatitis. (A'o/r. Other filters for applying very hard .r-rays are .' mm. copper <,r 10 nun. aluminum in lean patients; or 1 mm. copper ordinarily.) (.\ i>t< . Most of the above .r-ray dosage is quoted from other writers. The author's own dose is 0-inch spark. ^ ma., five minutes at 10 inches distance.) (Xatc. The 6-inch spark in the author's dose for radiotherapy is measured be- tween moderately sharp points. If measured bet ween polished walls J inch in diam- eter the spark would be 4-2 inches.; 1. STALKS OK HAHDNKSS OK .r- Benoist (Bauer same values). Wehnelt. Walter. Degrees B. Degrees Wh. Degrees W. (About) 2 l.S to 2 2 to 3 3 O 4 to o 4 6| o to 5 7| 6 8 to 7 7 9 ? s 10 to 11 7 to S Knits H. Tints. Knits. Tints. Knits \. Kaloms. 1 II 2 X l.l H 3 X 1 kalom :{ H 4 II 5 II- Tint B 4 H 7 to v I! 'int 'int to I 'int I 'int I to 11 'int II ti X s X 10 X 12 X 14-10 X 2 kaloms o.j kaloms 11 II int III 2s X 20 to 22 II 'int IV 40-44 X 'Arch. dT.lec. Med., July. U'T I'^rvtht ma dose. 1172 MEDICAL KLKi TKK 1TY AM) ROXTdKX KAYS ^T-RAY TREATMENT IN PARTICULAR DISEASES SKIN DISEASES The .r-ray produce.-- atrophy of the more highly specialized elements of the r-kin. Thi- is utili/nl -in the treatment of acne, sycosis, hyper- trichoMs. and excessive sweating'. Acne.- Schamberg 1 regards tlie .r-ray as the mo.-1 important single therapeutic measure in acne, hut says that other measures are to be coinhined with it. (^specially expression ot the comedones or black- heads. The latter is a measure which the present author regards as undesirable on account of scarring; freeing the sebaceous glands by Irictioii with tar soap and warm water seem to me preferable. The applications may be of the frequently repeated mild type or of a more severe type, such as 2 Holzknecht units repeated every couple of weeks. In eh her case it is necessary to produce a slight reddening of the sui'face, and the anticathode should be 10 inches or more from the face, so that the effect may be about equal on the whole surface exposed. The vacuum should be the lowest that will produce a brilliant radiance in the lluoroscope (resistance about 1 inch, radiometer about 2). The eyes. hair, and eyebrows should be protected, a localizing shield being very convenient. Treatment by the .r-ray alone will effect a cure in the majority of these cases in from three to six months. Combined with hiirh-frequency currents as a stimulating application the time is somewhat shortened and the assurance of success is greater. My own treatment is the .r-ray and high-frequency currents combined with the following medicinal means: Internally. ir,-. ij : .... ... :JT. I : LT. v : ur. v: ;ul. ,~ ij. M. 1 his is m \- t reat mem fur all forms ot acne, and the wor.-l cases even of a<-:;<- ro-acca have been completely and permanently cured. ( )nlv the ./'-ray treatment i- required in this combination, and this is an e-pec;al advantage, because more severe applications of the .r-ray mav lie -kin. The latter condition resembles t he shrivelling 1 ii a Lie. 1 consider it uiiuecessarv t o sqiiee/e out comedones mde-irable to incise or curet the pustules. The scarring that '' . liy that -ort of treatment i- sunplv terrible. Hypertrichosis. Mild repeated applications of the ./--ray, scarcely than to uraduallv Ian the skin, are entirelv ineffective in i 1 !'!)!. To succeed it i- nece.-sarv to produce a the -km accompanied bv lo.-s of liair. 'I'his must be repeuti , alter about three months and perhaps more than once after that, 'i ' '"ollicles can certainly be destroyed, but whether V ^'i.rk Mc.lical .JciuriiHl. Fch. _':;. I'jiiT. ROXTOEXOTIIERAPY 1173 this can be done without producing sonic degree of atrophv of the skin is questionable. With careful management, this atrophy mav he -o slight as to he a very great improvement over the original condition in cases with almost a heard, hut in cases with just a slight exaggeration of the normal downy growth ,r-rav treatment is not to be recommended. Tor .r-ray treatment the vacuum should be low, the neighboring parts of the face protected, and the application may consist of .'! II. repeated once every six or eight weeks during six to twenty months; or of '1 II. every three or four weeks for six months, then stopping for two months to see whether the atrophy is uoiiiLi' to be so marked as to make further treatment undesirable. If this is not 1 lie case treat ment is recommended. Another plan is to give a course of from six to ten treatments of such a nature as to produce a reaction from their total effect, and still have each treatment so mild and the intervals between them so long that when the reaction begins the treatments may be stopped with a knowl- edge that the effect will not go to an undesirable extent. This reaction should be accompanied by complete loss of hair over the exposed area, and after it has subsided the skin should be left as smooth as a baby's. The hair almost all returns after two or three months and the course of treatment has to be applied again. Three or four courses of treatment may be required during the course of a year, and are likely to be partly successful in permanently lessening the amount of hair. This method is attended by the usual risk of causing slight atrophy of the skin, and too severe a reaction must be guarded against tor two reasons one because it is painful and temporarily disfiguring, and another because it mav give occasion for some legal claim against the operator. The pa- tient ought to be told that the treatment necessarily involves the pro- duction of an inflammatory reaction, or ".c-ray burn,' accompanied by .-on ie redness, pain, and swelling, that it is not certain that all t he hail' will be permanently removed, and that there is some possibility of the skin being left somewhat thin and puckered afterward. It seems to be a matter which lh" operator should approach with a feeling that there is probablv very little credit to be gained from treating such a case and that the wrong kind ot a patient may make trouble tor him. It may be undertaken at the earnest solicitation of a patient who is disfigured by a regular beard, and who understands that the iv-ult may no; be complete destruction of all the hairs and that there may be some effect upi m t he skin. A patient lias recently been seen by the author who was treated eight yea!'- ago in another city. There had never been any redness or pain or swelling. The hair had -imply fallen out, but had returned, and six month.- later atrophy and shriveling of the .-kin -et in. This has re- cently become less and les- apparent . but t he chin .-till look- a lit t le as if it had been the seat of a very mild but thickly di.-tributed small-pox erupi ion. f A i'i>! icdt /mi _/'kin. The desired dose having been applied the applications were stopped and the further progress of the reaction was noted. The portion of the face which had been treated became quite a fiery red and somewhat swollen and quite painful. This gradually changed TO a darker red or almost a brown color. There was desquamation of the epidermis and com- plete falling out of the hair, but without any ulceration. The face had to be treated in several different sections, each part in succession receiv- ing the amount of exposure specified above, while the rest of the face was protected by sheet lead. Besides the atrophy of the skin, there may develop a dilatation of the superficial blood-vessels, such as seen upon the noses of chronic alcoholic subjects. X-ray treatment, then, is indicated only in seven 1 cases where the resulting slight changes in the skin amount to nothing in comparison to the relief experienced from tin- removal of the original disfigurement. The more experienced the operator, the better within certain limits will he be able to regulate the changes produced in the skin. The use of an aluminum filter, 1 mm. thick, and the application of single doses of 1 Sabouraud (o^ H.), or a little less, is apt to cause falling out of the hair without inflammatory reaction : it may have to lie repeated several times to secure any permanent removal. Favus. In this disease, when it- affects the scalp, the .r-ray is probablv the best means of treatment. The object should be. by one or t \vo vigorous applications, or bv a serie.- ot frequently repeated milder ones, to produce complete temporary loss of hair. After this has been produced it is easy enough to eliminate the fungus by suitable 1 medica- nieiits, but this is not the case if any hairs have been left. 1 he scalp ,-lioul' 1 be exposed in four different sections i frontal, occipital, temporal. an 1 ! parietal) and the anticathode should be tar enough away (about ](i inches) to secure uniformity ot action. Sheets ot .r-ray metal torni the onlv sat i.-t'actorv protection while each particular portion is exposed. If one full dose is given it should be ot' lor.") II. (Holzknechl units), aii'l it -hould be repealed after three or tour weeks over any portion v. hi'-h has not become depilated. '1 his treatment produces a very decjilnl reaction, which is most severe in the regions already inflamed by the disease. The hair falls out and there is considerable desqua- matiori. The hair begins to grow again six weeks after it has fallen out . e, the follicles which have been de.-t roved by the favus not regenerated. The application mu-1 not be too severe llicles will be destroyed by the .r-ray and the part remain ald. I hi- i- Holxknecht 's own method, but Freund. of o-i operator- in America secure the same reaction in the ito.vn ; KNOTH KHAI> Y 1 1 75 course of three weeks by repeated milder applications. A medium degree of vacuum should be used. Alopecia areata is treated in the same way as favus and with fairly good results. The application need not extend more than \ inch beyond the margin of the area affected, and must be somewhat less vigorous for the beard than for the scalp. Neither in this disease, in favus, not in any other is it likely that the beneficial effect is due to bactericide action. In favus it is good almost solely as a depilatorv. and in alopecia areata it has a slight stimulating effect upon the hair follicles. This last is shown even when no visible reaction has been produced. As the result of .r-ray depilation for alopecia areata is some- what uncertain it may be wise to follow Freund's suggestion and try the effect upon one small area before treating all the regions affected. In no case should repeated severe reactions be used that would destroy the hair follicles entirely. Sycosis. Y-ray treatment gives excellent results, the technic being the same as for favus of the face. It is one of the diseases in which the .r-ray may be regarded as a specific. Psoriasis. One full dose of '_' II. for the face or o.\ II. for the body sullices to cause the disappearance of the patches over the area exposed. The hair should be protected by .r-ray metal. No inflammatory reaction should be sought. Recurrence is as liable to take place as after any other treatment. Or smaller doses may be given, and repeated every day at first, and later every other day. until the appearance of the slightest possible reaction. The vacuum of the tube should be medium or low. The author's experience indicates that the diseased area is much more susceptible to the .r-ray than the surrounding skin, and also that a second course of treatment finds the diseased areas with an increased susceptibility. The point of the elbow where the disease is often present is particularly slow to heal after a severe dermatitis. Smaller doses than usual should be used in recurrent cases of psoriasis. The way in which the patches disappear is quite remarkable. There is no doubt about this being due to the application of the x-ray, because areas which receive a sufficient dose clean up completely, while thor-e insufficiently treated do not show complete improvement. The center of a large patch may become perfectly clean if the tube is close to the surface and is kept in one position, while the edges are but slightly improved. The distance in this case from the anticathode to the psoriatic patch, may be considerably greater than from the the middle of the patch. As the intensity diminishes lare of the distance the tube must either be at a consider- o as to reduce the difference in the relative distances, or the tube must be changed from one exposure. A greater distance 1 requires If success requires equal exposure of all parts of a single patch it will be readily seen thai a number of patches on different aspects ot a limb must be treated individually. The application >hould lie limited to the areas of disease and a small /.one of surrounding skin. This is not to prevent undue action on the neighboring skin. for. as already mentioned, the dose required to affect the diseased an -a is smaller than that required to affect the sound skin. So many regions of the body are affected that application to all of them with a bare x-rav tube miirht produce some undesirable 1170 MKim AL KLKCTHU'ITY AND KONTCiEN KAYS effects baldness, sterility, e>r constitutional disturbance. Such a shield as the 1 Kipperger is use-fill. It is a box made e>f opaque material com- pletely surrounding the 1 .r-ray tube except for a 4-inch opening;. This opening is directed toward the 1 part to be treated. Smaller diaphragms may be used, or a piece 1 e>f shevt leael may be 1 fastene*d to the surface of the body with an ope'iiing e>f the 1 right size anil shape to expose the pse>riatic pate-h to the' action of the .r-ray. Lipoma.- This disease*, especially Dercum's disease, has been treated by the applications of .r-rays Xe>. 5 to Xo. 7 Be-noist. Xogier, 1 who reports sue-h a case 1 , founel that the fatty tumor would diminish in size but not entirely elisappear. The pain of lipomatosa dolorosa is quickly relieveel by the' same treatment. The disease take's a long course of .r-ray tre'atment, and there does not seem to be- any great probability of cure-. Massive e loses of 4 or 5 II., repeated every two or three 1 weeks, ha\v been use-el in the- e-ases thus far re-porte-d. Keloid.- The* successful treatment of the disease by the .r-ray has bei'ii reported by many different operators, and it can no longer be con- sidered xub JHflice. Some degree of re- action should be exe-ited, but no ulcer- ation. Kays Xo. "> and a quantity of about (') H. may be applied once in five of six weeks, or milder doses, amounting to the same total, in about three* weeks, and t he-n followed by an intermission of three 1 weeks. The* case 1 shown in Fig. 813 of keloid of the lobe' of the ear was given a num- ber of .r-ray applications at St. Barthol- omew's ('Unie- with commencing bene- fit, but abandoned treatment be-fe>re it wascomple-te-. It was more of a tumor than most e-ases of keloid. They are often more 1 like hypertrophied se-ar-tis- sue- and are then more* quie-kly amenable to treatment. It take's from three to six months in any ca.-e, and t he-re are* so far no < >bservat ions to show whether it removes the tendency to the develop- ment of thi- abnormal tissue in new It i- a t rea tment which is to be extent, where electrolysis - in it t he only successful ic-1 one. Treatment bv '/'' ',,.^'1,/n/i in in '/if Trait nn nl of Ktlnid. Thi- me 1 hod of treatment : bv the author in l^'.M.' and consist- in the- internal ad- ( . liypndcnuie ii-' 1 ' 'f the druu in question. Thiosina- inin ; |)roduces a very marked ten UK irary leukocytosis ;il id n i-iii'v to cause the absorption of fibrous or ricat ricial tis- ,iir. [ n kdoid, in which it noi only causes the absorption , remove's the constitutional tendency to it. \I,-,). IV..P, iin-1 i Tin.. I-. :Ji v.">. M.-iy l>."i, I 1 .)!)."). M. lir:,! .Ir.unial. \^\. RONTGENOTHERAPY 1177 The importance of the latter feature is very great. These rases develop a larger keloid in the scar if the original growth is excised. Thev develop one in each needle-puncture if hypodermic 1 real inent is adopted. A keloid developed in the scar from too intense photo- therapy in a case reported by Helot. A case treated by the author was one of a college student who de- veloped keloid in a vaccination scar. After one excision this formed a large mass with numerous prolongations, disfiguring and greatly disabling the arm. Thiosinamin was at first used by hypodermic injection near the growth, but as new keloids soon developed in each needle puncture the method ol administration by capsules to be swallowed was adopted. Treatment had to be continued for about a year, but resulted in a complete cure of the growth and of the tendency to the formation of others. \\hether the .r-ray alone will cure the tendency to keloid is a question rot yet settled. Cases of multiple keloid have been reported by Sievers' which were cured by the x-ray without any other medication and had shown no recurrence in two years. l\adium is used very successfully for keloid by the author and others. Hyperidrosis. This disease has been treated by the .r-ray and a successful technic described by Leopold Freund.'-' My own technic is illustrated in the following cases of UK st extni- ordinary hyperidrosis palmaris. The patient, a phy-ician twenty- seven years old. had always suffered from such sweating of the palmar surface of the hand and fingers that sixty seconds after wiping his hands on a towel the unnatural secretion would fall from his finger-tips in great drops. The treatment consisted in a single massive doe of each hand of unfiltered .r-rays about Xo. 7 Henoist penetration and Fi \, Tousey inten- r-iiy and about 10 Ilol/knecht units of quantity. Thi- dose was applied from a tungsten anticathode 7-inch bulb excited by a 1'J-inch induction- coil with a wheel mechanical interrupter. The primary current was .") to I) amperes, the ^econdary 1 to ]\ ma.: the distance from the anti- cathode to the -kin It 1 , inches and the time of exposure twenty-right minute-. This was more than a Saboliraud and Noire ery.thema dose of -V, 11., and was made possible by the toughness of the >kin in- vnlved and preliminary tests of it- sensitivenes.- in this particular ca-e. The result was redness and -welling coming on after a period of incu- bation. I Vy desquamation, except in one -mall area where there was an actual blister. The -kin was left -niooth ar.d dry. and when seen a few month- later the palmar surfaces were as dry a- a bone. Thi- radiance required an expo-ui'e of -ixiy n mute- upon a Sabou- raild barium platinocvanid pastil at o' 1 , inches from the anticathode to change it to Tint IV Sixtv minute- at !> inches twice a- far as the p: -til would, t here fore, have applii d a Sabouraud do-e to the -kin and on< -quarter thai lime or fifteen minutes would have been a Sabouraud do-e at (I 1 , inches, the di-tance at which the application was actually made to the skin. ./-I 'ay applications ab-olutely and permanently -topped this disease. but were followed by kcratosis and fissures requiring treatment bv ilsures. Warts and Moles. These may be treated by frequent exposure to mode-rate doses or a single 1 exposure te) a very heavy dose (X LI.). In the latter case 1 it is very important to prefect the' semnd skin. Some ot these show a tendency te) de-velop into epithelioma, and in such cases it seems probable that the 1 slower milder tre-atment is better. There is ,-ome reason to belie-ve that a severe change in the 1 skin from the 1 .r-ray produces m some cases a tendency toward malignancy. Piaelium is the author's preference and high-frequency sparks his ne\t choice for these cases. Pruritus. Itching of the- skin, with or without anatomic change 1 , i- relieved by mild applications of the x-ray combined with the use of high-frequency currents from ultraviolet ray vacuum electrodes or from opper electrodes. This, however, should be combined with other appropriate treatment, such as an ointment containing resore-in. car- bolic ;icid. alum, and ichthyol: the internal use of salophen, 10 gr. three' time- a day. The latter is of the greatest service 1 in the cases which are dependent upon a uric-acid diathe.-is. Nevi. Va.-e-ular or hairy nevi or port -wine stains may be treated by the ./'-ray, but mild application- produce little or no effect. There nr> 1-1 be a very marked reaction, although it is better to avoid ulceration. After successful treatment the skin may show slight atrophy and its may not be absolutely normal, having somewhat of a cicatricial In the-se cases the choice of treatment lies bet ween radium, e, electrolysis, exci-ion. and the ./--ray. Where the nevus is at it is possible to -ecure' a linear cicatrix exe-ision is best. -i- i- excelle-nt for nevi of moderate -i/e where the' cosmetic \'-i-ion would be bad. The .r-ray i- adapted to case's of large- 1 in which the disfigurement i- so great that the result ob- .n though it can hardly be expecte-d to be perfect, will be a ' improvement . In the-e cases a .-ingle- elose of } H. may be \i the neighboring part-, and repeating it after a month. id do-e- mav be the -am<- or of -lightly greater strength, de- ipon the degree- of reaction. The vacuum should be medium, KONT< i KXOTI 1 K K A P Y 1179 and if repeated fractional doses are given the radiance should he rather hrilliant, so as to he a little more than tin' standard dose on p. 1 !(>(>. The decree of reaction sought is one accompanied hy slight blistering, hut without ulcerat ion. Chronic Ulcers. The .r-ray does not appear to have any specific effect upon an ulcer, hut exposure to the r-ray may produce two different results. There may be a stimulation due to the charge of static elec- tricity emanating from the .r-ray tube and having a tendency to stimu- late healing, and then' is a regular cloud of atmospheric dust repelled from the .r-ray tube, and if a raw surface is exposed to this a dangerous implantation of bacteria and other particles may take place. This last effect may be prevented by the interposition of a thin piece of cloth. Mild doses, like those on p. 1 !(>(>, repeated only once a week, may be used. There are so mtftiy better applications, electric and otherwise, that the x-ray will hardly be chosen unless there is some special reason, such as the fear of a development of malignancy. Syphilitic Gumma. A ease of ulceration of the side of the neck from a broken-down syphilitic gumma, which had remained open for a couple of years, was successfully treated by means of high-frequency effiuves and very soft .r-rays. 1 Syphilitic Rhinoscleroma. A case referred to the author as prob- ably one of lupus, but which was subsequently thought to be of a syph- ilitic nature, did remarkably we'll under .r-ray applications, and was promptly and completely cured when antisyphilitic medication was added (Fig. 814). Scorbo, of Naples, has treated a syphilitic lesion of the skin by ultraviolet light and the .r-ray. Rhinoscleroma. FreumF reports the cure of such a case by twenty- five applications of the x-ray. The nose was thick and indurated and the nostrils were blocked up with nodules, which also involved the hard palate and the posterior wall of the pharynx. Ditt rich's bacilli had been found in the tissues. Leukoplakia Buccalis. Lednr' reports :> cases treated by ex- posure of the tongue to medium soft rays at a distance of 20 cm. ^ inches) from t he ant icat hode for two minutes at the first treatment, possibly repeated in three weeks. The letikoplakia completely and permanently disappeared without the sound part of the tongue show- in sj; any effect from t he apphcat ion. Cicatricial Contractions. These yield slowly to the influence of mild applications of the .r-ray. Thiosinamin is also excellent in these cases, and requires to he given internally for six months or more. Its effect is more fully explained in the paragraph on keloid. 1 Laquerriere, Bulletin officiel <):>. p. 127 ' Arch. (I'Klectric'ite Medicale, Feb. 10. 190 11X0 MKDICAL Ki.KeTKK Try AND HONTOKN HAYS Effects of War Injuries. 1 - Fibrous tissue forming about nerves after war injuries is absorbed by .r-rays. 10 or 12 II. under a filter, once a month with cross-fire, without injury to the nerve and with restoration of function. Also adherent cicatrix. painful cicatrix. keloid. neuritis, ankvlo-i-. Heaujard 1 -' finds benefit from the .r-ray in crippling or painful wounds, neuroma, cau-alsiia. and cicatricial compression of a nerve. Laquerrieiv advises it in infiltration and inflammation of tendon sheaths, and old hydrarthrosis. It is most effective in the case of young cicatricial tissue. Leprosy. Thi- is a disease in which some of the cutaneous lesions are susceptible of improvement by r-ray treatment, and, according to Ouilin. th" .r-ray -eems to have a specific effect upon the morbid tissue wit hour affect in t he neighborin.ir sound tissues. The application should be -uflicient to produce a mild erythema, not *ulceration : 5 or (i Holx- knecht unit- should be applied to each of the regions treated. This amount may be a single dose or divided amonu; several sessions. Scholtx. on the other hand, did not observe any decided benefit, clinically or microscopically, from .r-ray applications in 2 cases of leprosy which lie treated. From a study of cases of leprosy made in the hospitals of Norway it seems TO the author that the r-ray may be of service* in the treatment of the tubercular cutaneems and subcutaneous nodules and of the chronic ulcers which characterixe the disease. The* larire-r question, as to whether the disease itself can be cured by .r-ray applications ove-r the spine or the hematopoietic organs, must lie left undecided, but when one sees case after case which has suffered from the steady advance* of this terribly mutilating disease for fifty years it seems as if an effort should be made* to conquer the 1 bacillary infection or the trophoneurosis by .r-ray treatment. Applied in these two directions, and with courses of treatment extending over long periods of time, but only to the extent of causing stimulation of the .skin, never ulceration, it may prove the means of curing the disease. We know of nothing else in the whole Pharmacopeia which has so marked an effect upon the whole organism in therapeutic de>ses. .1 (.''!.-' nf Leprosy Apparently Cured Inj the x-Ray. This case is re- ported by Victor G. Hciser of the Leper Hospital at Manila." The different le.-ions wore exposed for ten minutes every third day to a ie-e ju.-l intense enough to show the out line of the- in tra carpal bones An ordinary .r-ray tube was used with an 1^-ine-h induct ion- d a mercurv turbine interrupter. The distance' from the tube was IPS. for tl e fir.-l three we-e-ks, beginning Nov. .">, I'.tOti. but improve- cte-d u mil after the distance* had bee^n reduced to or 7 June. l'.!O7. after .-even month.-' treatment, the lesions red. Miid the lepra bacilli, which had be-en abundant, Jo demon-irate. l'-v Januarv. I'.'Hs, after fourteen no ane'si hot i< !, Ji HP and -buy, I'.iOs, it wa : bodv. At the 1: : ; l . I ' RONTGENOTHERAPY 1 181 190S, after nearly two years' treatment, the patient was apparently cured. Scleroderma. Encouraging results have been reported from ap- plications of 6 or S llolxknccht units of Xo. 5 rays made every three weeks. The sclerotic patches are apparently less sensitive to the x-ray than normal skin; for these rather large doses do not excite an inflam- matory reaction. Xo complete cures have been reported. Chilblains. The redness and pain are relieved even in severe recurrent cases by the .r-ray and high-frequency currents. Ichthyol ointment is excellent and so is white lead. The author has had very great success in treating these cases by immersing the feet in mackerel brine, as hot as it can be borne, for about fifteen minutes. This may be repeated in two or three days, and these two applications will probably suffice for the whole winter and there may never be a recurrence. Tinea Capitis or Ringworm of the Scalp. The discovery that the .r-ray is the most effective means of treating this disease is due largely to Sabouraud and Xoire, and their names have become associated also with a convenient method of measuring the dosage of .r-ray required for the treatment of this disease. Their method is to apply rays of & medium or low degree of vacuum (Xo. 4 or 5 Benoist), with a sufficient exposure to produce complete falling of the hair without inflammatory reaction, and without ulceration. Their method of measurement is based upon the change in color undergone by barium platinocyanid when exposed to the .r-ray. A little tablet coated with this chemical, which is the same that is used in fluoroscopes, is placed S cm. from the anticathode, while the surface to be treated is at a distance of 15 cm. \\ hen it has turned to a standard color, so as to exactly match one of the brownish-yellow tablets supplied with the apparatus, we know that a certain quantity of .r-ray has been applied. One of the test tablets indicates an exposure which is about 1 he proper dose for ringworm. This indicates the application of ">.', 11.. which is the large.- 1 dose that can be applied without producing radiodermatitis. The quantity to be applied varies a little. Only 4 11. is required for a child, and o 11. is the average dose for application to the hairy scalp in adult.-. The Sabouraud and Xoire pastils form a most convenient means of measuring the dose. Haivt's little device holds the pastil attached to the .r-ray tube at just the correct distance from the antieathode. Ordinary light affects the barium platinocyanid, so the pa.-Hl is kept covered by black paper, except occasionally, when it is tinned back for comparison with the test object , which also is held in position. It is not necessary to turn off 1 he current while making this comparison. Holzknecht 's chromonu hornet er. depending on the change in color of another cheinic compound, may be used. The author's own method is based upon the intensity of the ./'-rat ha nee. which can be measured before tin- exposure is begun, enabling one to determine beforehand just how many minutes the .''-ray is to be applied. It is described on a not her pa ire and is excellent for many pur- poses, but presents too great a personal equation for general use in these part icular cases. The treatment of these cases without any exact means of measuring the amount of .r-ray applied is to be most strongly deprecated. Before the introduction of the Sabouraud and Xoire method of app'vinir an exactly measured dose at once or in two parts, separated by a day or two, the best radiologist had most uncertain results in these cases. MKDICAL KLECTHH'ITY AND KOXTGEN KAYS An example of the best technic would be (i-inch spark, 70 kv., 400 ma. seconds at 10 inches distance for the total application over any one area. At a distance of 1"> cm. from the anticathode to the skin in one of the author's exposures with another technic twenty minutes amounted to about 4 llol/knecht units, and was suitable for the total dose, not to be repeated, in a case of tinea capitis in a child three years old (Fig. SI")). The treatment was successful. All portions of the scalp that are affected must be treated, and all must receive an equal application of the x- ray. The strength of the rays and hence the quantity ab- sorbed in a given time varies inversely as the square of the distance from the anticath- ode. The convex shape of the head would result in the part directed toward the .r-ray tube being very much more affected than the other parts if a single exposure were made in a fixed position. It is nec- essary to turn first one part and then another toward the tube, protecting other parts by sheet -lead while one part is I icing t reatecl. Practically t he whole scalp may be treated in four sections frontal, oc- cipital, and right and left parietal. It is unwise to attempt to make this subdivision of the exposure by means of a diaphragm which regulates the distribution of the rays from the tube. Such an arrangement is excellent for treating a single area, but it would be very difficult to prevent some contiguous portions ot two neighboring areas from receiving a double exposure, and other parts would perhaps not receive any. I'sing the sheet-lead, a portion on one side of a perfectly straight line may be treated during the first part of the exposure and the portion on the other side of that line during the second part of the exposure. Kach successive part that is exposed is to receive an exposure of about I I lol/kneclit unit s. / Action <>f UK :f-l{(\\i nt Tinm ('u/nfi*.- -The disease appears to an infection by microorganisms which are limited to the ') of epidermis in the hair follicles. In this position the in- difficiilt or impossible to eradicate by any ordinary chemic ic;d means. The hairs break off if one tries to pull them out, Mo. HiiiKwcirin of the scalp (tino.-i capitis) cured I v .r-rav. R< ) XT( ! EX OTH E R A P Y 1183 The now hair grows out free from infection. The sound hairs of the area exposed to the x-my fall out just the same as the diseased ones and are also replaced by new hairs. The I) to 7 radiometer. but for the heavier doses the vacuum should be low. 1 or 2 inches spark resistance and 2 or :> radiometer. It will often be found advantageous to com- 1 line occasional curetaiie of cer- tain nodules with the .r-ray treatment. After the disease <:enn appears to have been . it will often happen that a complete cure will be promoted by Fin.-en treatment, and will not take place under the .r-ray alone even if ci iiit inued for a lonir t ime. Helot' analyzes the treatment of different forms of lupus as follows: " \\ hi le certain cases of lupus of the ext remit ies are benefited bv curet - au'e. any extensive case of lupus, whether ulcerated or not, ouirht to be ' . :.'; b;. the j'-ray : t his t real me in i.- more rapid ami effective. Kebei- lio .- points are to be treated by phototherapy, bin it may be that the produces changes in the tissues which interfere with the beneficial action of the arc Imht. Phototherapy properly applied Lnves excellent mall locali/ed lllpUS." authors to \\hom our knowledge of the curative effect i pus i.- due a re Jut assy, Sch iff. I- reund. Scholt z. Campbell, nerv. Ormsby, Kummel. (iocht, Albers Schonberi:. -ser. Lee, I'lahler, I hlmaiili. I'usey, Kienbock, Holx- \\illiam-. and P>elot. thi- disease was referred to the author by Dr. Jar- ie was -ixtv-seven vears old, and had had a patch of lupus the check for about a year. Her father had a similar he nose to ulcerate awav. MI A RONTGENOTHERAPY 1 IS") Tlic technic for ouch treatment was as follows: No. K) Miiller 1ule, radiometer No. 2.1 Henoist ; resistance 2.1 inches; S-inch induct ion- coil; Caldwell interrupter; Jl()-volt direct current; 1 amperes primarv current; 1 ma. secondary cunvnt; ant icathode and accessory anode connected; distance, S inches; intensity, No. 5 Tousey ; S ohm.-' resistance in rheostat. Five-minute exposure equaled 1 Holzknecht unit. The exposures were of two minutes' duration and thirty-five treatments were given in a period of two and a half months. The total exposure during this time amounted to about I I Ilol/knecht units. There was at no time anything more than the slightest decree of redness and itch- iu.il.'. A complete cure was effected and there has been no recurrence in three years. There is no scar upon t he face. It should be added that the diagnosis was made from the clinical appearance and history, not from microscopic examination. It is, therefore, not absolutely certain that the disease was lupus and not epithelioma. Absence of Effect Upon Hydatid Cysts. There is no apparent reason why the .r-ray should succeed in destroying the parasites which cause this disease, and Deve has found from experiments on this disease in rabbits that this supposition is correct. Rontgenotherapy for 1'yorrhca Alvcolarix is described on page tilt;. X-RAY THERAPY IN TUBERCULOSIS Experiments by Bergonie and Tissier 1 showed that the x-ray had no effect upon the tubercle bacilli in a culture, and that it had no marked effect upon the lesions of experimental tuberculosis. They concluded that the x-ray had a doubtful influence upon clinical surgical tubercu- losis and none upon phthisis. Miihsam, at the same date,'-' found that the .r-ray did not produce tuberculosis in guinea-pigs, and that it only slightly attenuated the' local manifestations of this disease if the animal was inoculated with it. The x-ray did not completely cure tuberculosis in guinea-pigs. Rodet and Bertin-Sans, about the same time, :i found that the x-ray had an unfavorable effect upon nutrition, and that in cases of tubercu- losis the x-ray moderated the infection in the lymphatic glands, but somewhat favored generalization in the viscera. Their verdict was that no benefit resulted from the treatment. Hieder, a little later, 1 came to the conclusion from his observations that, while the x-ray appeared to attenuate or kill different di>ease germs in glass test-tubes, the rays had no such effect upon infectious processes in animals inoculated with different pathogenic germs. His results at that time seemed to show that local tubercular processes were favorably influenced, and that in some cases generalization of the disease was antagonized. The animals experimented upon died, however, doubtless from organic disorders produced by the irradiation. lie reported neg- ative re.-ults in human tuberculosis. Since that time increased knowledge as to the dosage of the x-ray has led to improved re.-ults. and the x-ray has become a most valuable therapeutic au'ent. especially for localized tubercular lesion-. Bergonie* 1 Congress of Tuberculosis, 7ti. P;iri.-. 1>',)S. - Munch. Mcl. \V,ch.. _'t. 715, Nov. in. IV.K. 3 Arch. .I'Klcctnntc Mc.lirale, H:;. iv.tv 4 Munch. Mes',l, Paris, March 27. 11)0.1. finds I hat. with modern technic. the .r-ray has a clearly favorable effect upon iion-suppurat ive tubercular glands. According to tin- observer all the tunietieil glands which are treate ma. Kadi applica- tion amount- to about \ Holzknecht unit, and the application may be kept up for- three or four weeks if necessary and then intermit fed. Tubercular Adenitis. Chronic tubercular gland- with periadenitis, treated by Hoiit'_!.en rav. may become -mailer and change to fibrous nodule- which do not entirely di-appear. Acute tubercular glands, and tho-e aheadv havmg-a tendency to soften, may be caused to undergo chee-\ degeneration. The author has observed excellent results from .'-: :" treatment m -uppurative tubercular glands oj the neck already opened spontaneously or by the surgeon'.- knife. He has successfully ca-e of chronic -inu- of the liack following an operation for ilar o-teitis or tubercular arthritis of the -pine-by exposure to the The ,/--ra v.- were of a qualit v of a bout No. ."> ] lenoi-t . The ant i- iboul IK indie- from the -urface o| the t>odv, and the ap- For about five minute- every other day until the skin be- 1 ddein-d. Kadi application amounted to about 1 Hol/- I !< .'it 'jenot hera pv re-ull- in better cicatrices as well as in ca-e- of tuberculous abscess and -mil-. Tubercular Lymphatic Glands of the Neck. These are readily KONTCKXOTHKKAI'Y US? amenable to treatment by a radiance of a penetration of No. "> or (> Benoist. Short applications of about a minute and a half, at a distance of about 10 inches from the ant icathode, may be made three times a week until some reaction appears. Then the treatment should be inter- mitted. Kach application, made according to this plan, should he calculated to be a little less than 1 Hol/knecht unit. Another plan is to make massive applications of 1 or ."> II. at a single session, or as 1 he total of two or more sessions, occurriim' within the course of two or three davs. \o more application- should be made tor two or three week-, but it mav then be repeated. It i< quite important to limit the application by a shield or by c<>vennu' all other pa Us ot the patient with -heet lead. Haldne-- and sterility and any possible toxemia ai'e thi- avoided. The re-tilt- are that the glandular mass shrivels and certain uland- cease to be palpable, while others remain as innocuous -mall tihrn'i- iiodule-. Leonai'd found that the lymphatic vessels are convertei into iilii'ou- cords. ( 'a-e- treated hv the author make thi- treatini 11SS MEDICAL KLECTKICITV AND H(")NT(iEN RAYS tubercular glands of the neck seem preferable to surgical extirpation, because this treatment leave> no scar and because it permanently closes certain lymphatic channels and hence tends to protect the patient from general infection. Tuberculosis of the Mediastinal Lymphatic Glands.- Disease in this location is also amenable to treatment and the radiance required is one which will give a good fluoroseopic image of the chest, or will produce a good radiograph of the chest with an exposure of five min- utes or less, ."i-inch resistance. ()") kv., and '.') ma. The anticathode should be ]'.) inches from the surface of the body, and an exposure of three minutes may be given twice a week, with intermissions on the development of some redness of the skin. A screen for soft rays, made by interposing a piece of sole leather, or a single layer of tin-foil, or a sheet of aluminum ft \ T inch thick between the .r-ray tube and the surface of the body, will tend to prevent dermatitis while permitting the pas- sage of the more penetrating rays, which alone could reach the seat of disease anyway and which are less irritating to the skin. The nearest skin surface should receive about 2 Holzknecht units a week, and a distance of 13 inches is great enough not to make too great a dispro- portion between the distance to the skin and that to the seat of disease. If the tube were so near that the distance from the anticathode to the cutaneous surface were only half the distance to the deep-seated le-ion. the divergence of the rays would result in the skin being ex- posed to a radiance four times as intense as that which reached the mediastinal glands. Under such conditions it would be difficult to produce any therapeutic effect upon the mediastinal glands without a bad effect upon the skin. Massive doses are available here as elsewhere, but probably are less desirable than mild frequently repeated ones. The results of this treatment are variable, but it is certainly capable of great benefit in certain cases. Associated as this disease is so apt to be with pulmonary tubercu- losis, it will often be advantageous to combine the .r-ray and high- frequency currents in its treatment. Hypertrophy of the thymus gland causing compression and cyanosis or even suffocation has been successfully treated by Regaud and ( 'remien. They sometimes apply Hi II. units to the skin measured after having pa--ed through 4 mm. aluminum. A milder application is made twenty days later. Wei 11 uses the same filtration, but a smaller dose of ^ to 7 II. For example, anticathode b") cm. or inche-. and filter 7\ cm., or '.'> inche- from the skin and the application made from both front and back ( if t lie upper part of t he 1 horax. Tubercular Lymphatic Glands in Other Regions.- These are treated in t he same way and wit h due regard to t heir superficial or deep situation. The applications should be localized. Rene I)e-p]als ha- made blood examination- in patient- with tuber- cular adenitis treated by the x-ray and find- a reaction similar to that which occurs 111 leukemia under this treatment.' Tubercular Peritonitis. Kdntgen ray treatment ha- proved bene- ficial iii ;i ca-e of tubercular peritonitis in which an exploratory lapa- rotomy had been done and the fluid evacuated and the diagnosis ((in- firmed l,y the micro-cope. Repeated tapping was required until .7--ray 1 I.-- Radium, Sept. i:,. P.m.V p. :',OO. RONTGENOTHERAPY 1 189 applications were made. A lasting cure was obtained in this way, a slight recurrence disappearing at once under .r-ray treatment. The application in such cases should be over the whole front of the abdomen, of a spark resistance of (i inches. !> ma., sixty seconds without a filter or, preferably, one hundred and twenty seconds through o mm. of aluminum, the anticathode being at a distance of 10 inches from the skin. This amount of radiation is applied three times a week. The soft rays which might cause dermatitis are arrested by the aluminum screen. Tuberculosis of the Kidney. -This is a disease in which the .r-ray and high-frequency currents did good in one of the author's cases. The ./-ray seemed to act by breaking down exudative masses and the high- frequency currents seemed to stimulate the elimination of enormous collections of pus. The local condition was improved, but general infection had probably already taken place and the patient died. The applications should be limited to the lumbar region on the affected side. The anticathode should be 10 inches from the surface of the body and the radiance should have a penetration of Xo. (> Benoist and the same exposure a- tor tuberculous peritonitis. A screen for soft rays will protect the skin to a certain extent. The exposures should be given two or three times a week, and be of II., applied once everv four or five weeks, are permissible, but are probably somewhat less desirable. A mild con- tinuous effect seems usually better for tubercular processes, and this is a region where 1 the toxennc effect, which sometimes immediately fol- lows any .r-radiat ion. might be serious if the dose were a large one. The x-Ray Treatment of Pulmonary Tuberculosis.- A certain number of patients have recovered from tuberculosis of the lungs utidei treatment by the .r-ray and high-frequency currents and others under high-frequency currents alone. These recoveries have been character- ized by the disappearance of ail the symptoms of the disease, including the bacilli in the sputum, and by the radiographic findings character- istic of cured pulmonary tuberculosis. Other cases have shown considerable improvement under .r-ray treatment alone, and these cases have been mostly those in which the applications have been severe enough to excite a cutaneous reaction with a possible count erirrit ant effect. The best opinion at the present time seems to be that the .r-ray has little i! anv permanently curative effect m pulmonary tuberculosis. If ii is used either alone or in combination with high-frequency currents the technic is the same as for tubercular media -thud glands, and milt 1 frequent Iv repeated doses are lo be given with the production of a slight react ion upon i he skin. Tuberculosis of Bones and Joints. This localized form of disease is certainly benefited by the r-ray and some cases are cured. A chronic sinu- oi the back from ;m old operated tubercular osteitis of the lower dorsal vertebra 1 in one of the auil or's cases healed after a few applica- tion- of the ./'-ray and of hi:Ji-frei|uei;cy currents from ultraviolet ray vacuum elect 1'ot le-. I'ltbercula r rheumal ism oi the Wl'ist has been cured by ./--ray applications, and the ;;;iii. edema, and stiffness removed 1190 MKDICAL Kl.Ki TKK1TY AND HoNTCKN HAYS i reported l>y Rehoul', and Beclere ha- reported a case of spina ventosa, tubercular osteitis of a finger \viili fistula 1 , entirely cured by the .r-ray. It is to 1 ic recou iinei H let 1 at t he different stages of hone or joint 1 uber- culosis. when an operation does not seem to lie indicated or when it lias not proved completely successful and repetition oi the operation seems undesirahle. The .r-ray should generally he applied from several different direc- tion^, exposing only a small area of skin at a time, so as to secure an effect upon the deep tissue without much on the skin. The choice lies between mild, frequently repeated applications, continued until there i- slight cutaneous reaction, and massive doses, applied at one or two se- ma., at a distance of 10 inches from the anticathode, for t lie wri-t . hip. or spine. The mild frequent applications would require an exposure of one minut" two oc three times a week, and the massive doses would require five minute-' exposure at a single session, or as the total exposure, during the coin 1 -" of two or three days. The author's preference is for frequent mild application-. Xo severe reaction is to he sought, and the use of a screen for soft rays may he found desirahle. With o mm. of aluminum the expo-ure should he twice as long. lioedercr. 1 who has collected the published reports upon the treat- ment of tubercular joints and other local tubercular lesions, finds no evidence that .r-ray treatment tends to a general dissemination of the disease. Mv own experience agrees with this conclusion. Spina ventosa is very favorably influenced, while the .r-ray does not seem to accomplish much in Pott's disease or tuberculosis of the hip. ARTHRITIS DEFORMANS Anders, Daland, and Pfahler report excellent results from the application of the ./--ray in arthritis deformans. This treatment should be combined with other measures appropriate to the individual cases. The Author's Experience with the ./'-Ray in a Variety of Rheu- matic Affections. The .r-ray applications have a decided alterative ef- fect in this whole cla-< of cases and are a valuable adjunct to treatment by hijrh-frequency currents. The latter are applied by vacuum elec- trode-. A c;i-e without bony changes discoverable in the radiograph . . ly yield- re.-idily to the combined treatment. lony changes, however, do not appear to he cured, though the urea test benefit may be 'i in 'lie wav of arresting the progress of the disease. Illustrative (a-e- ;tre tn'-iit n >nei 1 on p. .V. ID. In the phy-iot herapy of war injurie- chronic ei't'u-ion- into joints ii it*-d by /-ray applications every two week- 'Hirt/ :; ). TRACHOMA 'il 1 - o| r-rav therapv in tin- di-ea-e have not been exactly 'hi hand- of different operator-. Ya--ioiit insky' 1 reports . ' I'-li the .r-rav certamlv had a inafkeil influence upon the -. e-pecj.-dlv the infiltration. The pannu- yielded RONTGENOTHERAPY 1 101 slowly. lie (lid not secure anv complete cures, no matter how long or how frequent the exposures were. This tissue seems to present hut a slight tendency to cicat ri/at ion. The applications were absolutely painless and produced no harmful secondary effects upon the eye. lie thought the .r-ray would give favorable results where other methods, have failed. Xewcomet has had better success in entirely curing cases. A difference in the results of Rontgenotherapy may be due to differ- ences in technic, and, generally speaking, it is desirable to know what the results of treatment with average apparatus and technic is likely to be. The exposures must be calculated with special reference to the avoid- ance of injury to th<> eve. In some cases little metal or enamel shields (Fig. 807, p. 1140) may be placed over the eyeball under the eyelids. A drop of cocain solution enables the eye to tolerate this. The eye is then entirely protected, and as much .r-radiance may be applied to the lids as is required. It is not necessary to evert the eyelids in order to secure an effect upon the mucous surface. Frequently repeated mild doses art' desirable. The penetration should be about No. 4 Benoist, the resistance or equivalent spark 4 inch, 2 ma., and the distance about 10 inches. Kxposures of two minutes three times a week amount to about 4 H. in three weeks, and this is about the proper amount to apply. The treatment may be re- sumed, if necessary, after an interval of a couple of weeks. The results of .r-ray treatment of trachoma while very good are not thought to be quite so good as those from treatment with radium. RADIOTHERAPY IN SYRINGOMYELIA Successful results have been reported by Heaujard and L'llermitte, 1 Delherm, 2 and Clramequc. :! The applications of the .r-ray are made over the affected part of the spine as indicated by the location of the principal symptoms and are of a degree of penetration equal to Xo. S Benoist or 7-inch spark. The tube should be at a distance of 10 inches, measured from the anticathode to the surface of the body. Applications of 2 Hol/knecht units may be given about every six days until the develop- ment of a cutaneous reaction and then reduced in strength. It is too early, and there have been too few cases reported, to know whether the disease is permanently curable by this means. Improvement seems to be reasonably certain. OLD SPRAINS 111 an old and very stout lady a fall down stairs resulted in a sprain ot the tuetatarsophalangeal articulation followed by pain and dis- ability until cured by the .r-ray :i year later. A localizing shield con- fined the ra v to an area about 1 ', inches in diameter. Six-inch spark, \ ma. Ill-inch distance 1 , ''> mm. aluminum, ten minutes. 1 he patient noted a -limy redness of the -kin and very marked improvement. A second application two month- later resulted in a complete cure. 1192 MEDICAL ELECTRICITY AND RONTGEN RAYS DISEASED TONSILS The author's treatment has l>een (i-inch spark, 3 ma., 13-inch dis- tance. 3 mm. aluminum, ten minutes. The application is external; the chin up and head turned to the opposite side. A protective cylinder 3 inches in diameter limits the rays to the region behind the angle of the jaw. One treatment is sufficient for one tonsil, and where both are affected each side of the neck may receive such an application at a single session or at different sessions. Hypertrophy of the tonsils disappears in a magical manner. A case of quite a different character had been tonsillotomized long before, but for a couple of years had had constant infection of the ton- sillor crypts from which a year ago stony concretions had been ex- tracted. An application to both sides at a single session cured the chronic suppuration. LOCOMOTOR ATAXIA The author has seen remarkable and lasting benefit from .r-ray and high-frequency applications to the region of the lumbar enlargement of the spinal cord. The applications should be localized, and mild and repeated ones are preferable to massive 1 doses. Probably no cases have been permanently cured. .v-RAY TREATMENT OF FACIAL NEURALGIA The .r-ray examination having verified the clinical diagnosis of neuralgia without gross anatomic lesion, the therapeutic applications mav be undertaken. The ray should be of a penetration of about Xo. (> Henoi-t. (i-inch >park. 70 kv., 3 ma., and the anticathode should be about 10 inches from the skin. Such an application may last about one minute, equivalent to 1 II., and be given three times a week. A locali/inii -hield and leather screen are desirable; 3 mm. aluminum require- exposures 1 wice as long. The hair and eye- are to be protected. but. generally >peaking. rather a generous area of the painful region i- to be expo-ed. A three- to five-minute application of an ultra- violet ray uia-- vacuum electrode is to be made at the conclusion of each .r-ray treatment. A rase of this kind was a lady about sixty-five years of age. referred to (he author by Dr. \V. T. Hull. She had suffered for twelve years from ob-tinate neuralgia of the upper jaw. which had not been relieved series of siirti'ical operations. The .r-ray examination showed :! bonv conditions. Twelve r-rav and high-frequency treatments '.' ere Li'ivt-n us indicated above, the ./--ray shining riii'lit through the cheek . : -. She had to leave the cit V at the end of tin- tune on account ot miner heat. The pain had then been onlv somewhat relieved, but i Hull reported to mi' the following winter that the pain had entirely 'a red during the summer ami had ,-hown no sign of recurrence. 1 ' ! N >'.\ iii'_r i- a case in which there was a deep-seated lesion which be readied by remedial agent.-: The patient . a lady of about '.'. a- b nm trhi in i he au t hoi- by Dr. \\ . K. Draper, with a his- ere pain, e.-pecially in the region of the right eye and -i the forehead. A supra-orbital neurectomy H'ood examination- had .-howii a marked degree 'I .-.' i-d onh partly to medical treatment: r-rav . ' ' ' u in i he jaw. ant rum. or t'n mi a! RONTGENOTHERAPY 1193 sinus. The treatment was chiefly by static electricity and high-fre- quency currents from ultraviolet ray vacuum electrodes. In addition there were a sufficient number of .r-ray applications for diagnosis and treatment to produce an effect in a case amenable to them. There was marked improvement for awhile, but never complete disappearance of pain, and at the end of a thorough trial the treatment was abandoned. The severity of the symptoms and the patient's poor general condition led to the conclusion that some very grave though obscure malady existed. Death ensued and an autopsy revealed a tumor of the right parietal part of the brain with considerable softening around it. Leonard 1 applied the .r-ray in >f migraine, tie douloureux, and facial neuralgia, generally with success. There was recurrence in one or two cases, but in most cases the relief seemed to be permanent. Tumor of the sphenoid shows distinctly in both the lateral and an- teroposterior radiographs of a case now under treatment with the. r-ray. Fit:. Mv Tumor <>f the sphenoid. An .r-rav apnlicatioti from in front. Pan of a cross- 'iide of the month. Six months later there had been >oine return of : M ft lira] Hi cord. Julv 1.1. P.m.-. 1104 MEDICAL KLECTHICITY AND KO.NTGKN HAYS pain, hut not much return of sensation in the portion of tin 1 lip supplied by the inferior dental nerve. A few months ago .r-ray treatment was begun, with a view to a retarding influence upon the regeneration of the' nerve and. if possible, to prevent bridging over the g;ip by newly formed nerve-fibers. The application- have been made both externally and inside the mouth. For both the .r-ray tube has been enclosed in a Ripperger shield and a cylinder diaphragm has been used. The distance from the anticathode of the Friedlander heavy anode tube (same model as the Miiller No. 13) to the outer or inner surface of the jaw has been 13 inches. A 12-inch induction-coil was used with the 110- volt direct current, a Wappler mechanical interrupter, 12-ohm resistance in rheo- stat, 3 amperes primary and 1 ma. secondary current. Rays, No. 6 Benoist. In the course of twelve days the application was of sixteen minutes' duration, on an area 3 inches in diameter on the outside of the face and ten minute's on an area 1 inch in diameter on the inside of the jaw. Three minutes of either application was equal to 1 Holzknecht unit. The first course of treatment then applied H. externally and 3\ II. internally in six different applications made during twelve days. The effect from some of the earlier applications was to cause com- plete disappearance of the pain, but the later applications of the first course of treatment were followed by a sort of stimulation of the nerve, causing temporary pain. The pain at every stage of the case came in paroxysms, and was located immediately behind the last lower molar tooth. The patient said it was just as if the lighted head of a match had broken off and landed on the gum. Treatment, in another city, by radium and by the .r-ray had been unsuccessfully tried before an operation was resorted to. There seems reason to hope for success from the application of the .r-ray after resection of the nerve, but the value of the method has not yet been proved. Treatment was begun Feb. S, ]!)OS, and as far as practicable has consisted of a series of courses of treatment, during which (j Holzknecht units have been applied bot h out side and inside in about three weeks, and then an intermission of three weeks has been allowed. On July 20. 1!K)S the outlook seemed very favorable, and the patient passed the first entirely comfortable dav for over a year. Twinges of pain when thev did occur were much lighter than formerly. The patient characterised them as xcHstitifinx rntln r Hi/in /min. A vacation from treatment during the summer was, followed by a recurrence, which did not yield promptly, and the pat H 'tit abandoned treatment and had an operation by alcoholic injection, which I believe has given encouraging results. PROSTATIC HYPERTROPHY The author ha- treated -everal cases and in some a tew .r-ray treat- liave produced a marked reduct ion in I he a mount ot residual urine turn of the abihtv to urinate without a catheter. The method , allowing the .r-ra v !o shine over I he perineum in t he direct ion late, the scrotum. ailUS, and bullock- being protected by a I hield surrounding the .r-ray lube. Mild application.- of netratinir ray. No. 7 IVnoi-t. (i-inch -park and 3 ma., two ' : 3 mm. aluminum at a distance ot 13 niche-, are made every otl [lol/knecht unit- in about two weeks. Treat m ' ' intermitted upon the appearance of >lihield and arrested the less penetrating rays, which otherwise would have been absorbed by the skin and wmiM have produced irritation. 119ti MKDICAL ELKC'THICITY AND RONTGEN KAYS X-RAY TREATMENT OF GOITER The method of aplication is to allow rays of a medium degree of penetration 1X0. G or 7 Henoist) to shine upon the front and sides of the neck from two or three different directions. A localizing shield is used to limit tlu^ rays to the proper region, and a solo-leather disk may be used to absorb the less penetrating rays. It may be necessary to wrap the chin in shrct lead, and it may be wise to cover one side of the neck with sheet lead while the other side is being treated. It is difficult, M. r-H:iv r n-;it im-ul of cxoiiht liiihiiir 1 n<>itcr. Brickiicr .-< tunr-stnml. ! nr-dlandcr 'uint of clnii Mill further rotccti-il 1 > .r-ni met i'h tlic loe:ilixer alone, to limit t he ray n:i the median line ti'om t \v< > successive anterolatenil in -. Mild n pea ted exposures tire to be preferred ', ti i 1 II. twice a week. livalen! t<> .i-inrh spark. - ma. for 1\\'o 1o four minutes at el In !:"-he- tmni the antieathode. |-]aeh of the l\v<> or -U!'laee -ueee i\'ely expired i- ti ha\'e \\\\< ainoiint me\vha1 iiii<-ert ain, alt luniIi the treatment i.- RONTGENOTHERAPY 1197 successful in a sufficient proportion of the cases to cause it to bo recom- mended. An experiment was performed by Drs. Luraschi and Fiorentini upon three puppies, all of whom had goiter. One of them was killed and the tumor examined under the microscope. Another was kept as a control and the third was subjected to x-ray treatment. This one died of IL:. N_'U. Exophthalmic goiter. Treatment by high-frequency currents applied l>y ultra- asphyxia after a few treatments, and a microscopic examination showed that the .r-ray had produced no effect upon the goiter. 1 Michaux has treated cases of u'oiter and obtained results in the hy- pertrophic variety, but the growth recurred when the treatment was stopped." Kobolko, on the other hand, reports a case of goiter cured by the x-ray. :! A glandular swelling in the neck may. of course, be one of the lesions 1 Le Radium. Sept. LI, I'.MIo. p. 300. - Ibid. ' Ibid. 119S MF.DK AL KI.K( TKH ITV AM) H(")XT(iKN KAYS of leukemia or pseudoleukemia, and in that case the x-ray produces pi isit ive results. Two other cases of goiter have been treated with benefit by Steg- niann. 1 Six treatments in one case and two in the other led to softening and reduction in si/e without any systemic disturbance. Steu'mann did not notice the special susceptibility of the skin to the .r-ray. which has been described by (lorl. Exophthalmic Goiter. - Many successful cases have occurred in the practice of the author and others. Every case should have an .r-ray examination of the teeth. The presence of a badly infected tooth will interfere with the cure. Mild repeated applications of the .r-ray over the thyroid gland and of a vacuum electrode from the ( hulin resona- tnr over the (nit ire neck resulted in the cure of a case brought to the author by Dr. Love. Before treatment the pusle was never below 1W): there was such a tremor of the hands that she could not pour a cup of tea. and such palpitation of the heart that it shook the whole bed and kept her husband awake at night. Treatment was continued for about three months, and when the patient returned to her home in North Carolina her pulse was 90 and all the ocular and nervous symptoms had disappeared. The thyroid gland had diminished in size. It had never been very large. No recurrence took place even during a period of great anxiety over her sick child the following year. The patient was examined three years later and was perfectly well. The method of application of the .r-ray is shown in Fig. 819 and of the high-frequency current in Fig. 820. Death After x-Rau Treatment of Exophthalmic Goiter. Yerning 2 re- port- 2 recent cases a month from onset; both received 5 H., repeated after one or two days. All symptoms were aggravated and death occurred in fifteen and forty-two days. Rontgenization of the suprarenal capsule in high arterial tension produces a decided fall and an improvement in the symptoms/' PERNICIOUS ANEMIA This is a disea>e in which the effect of the .r-ray upon the blood- forminu' ' iriians. t he spleen, and t he marrow of the long bones may some- times be of great benefit. The danger of causing toxemia and possible d'-at 1 1 make- it necessary to Use extremely small doses at the commence- ment, and some ob.-ervers < 1'ancoa-t > consider the x-ray absolutely '' ail r.-tindicated on account of the danger. Injections of diphtheria antitoxin in addition to the x-ray have been used successfully by Henon and Teixier. 4 iiODGKIN'S DISEASE AND PSEUDOLEUKEMIA AND LYMPHOSARCOM A licenses iii which ./'-ray applications to the affected RONTGENOTHERAPY 1 199 tumor which diminished one-third in ten hours mid was all gone in six months, and hemoglobin was raised (>0 to 90 per cent. The beneficial effect of the .r-ray is due to a direct action upon lymphoid tissue and to an effect upon tissue ferments (Kdsall). The affected lymphatic glands become a great deal smaller and the microscopic appearance is changed. There is a destruction and disintegration of lymphocytes with the presence of masses of chromatin derived from their nuclei. The gland may finally change to a fibrous nodule. In a case of Ilodgkin's disease, treated by Roth, 1 the glands were reduced to a normal si/e by .r-ray treatment everv other day for about three months. A medium hard tube was used, with the anticathode at a distance of JO inches from the skin over the neck and nianubrium sierni (there were enlarged mediast inal glands), and the duration of each exposure was from ten to thirty-five minutes, divided up over different glands. Two or three recurrences took place requiring fresh courses of treatment. Seim and Pusey were among the earliest to treat these conditions by the .r-ray. Pancoast has collected the reports of 44 cases treated up to 1907. and finds for this general group of diseases of the lymphatic glands without marked blood changes ./--ray treatment in 29 cases, of which the final outcome is known, has given 25 per cent, of cases which are alive and apparently well from one to four years after the first symptomatic cure, and (10 per cent, have died, while 2 of the 4 cases still under treatment are likely to die and the other 2 seem likely to get well. Rosenberger 2 has treated one case of pseudoleukemia with some reduction in the size of the spleen, but without much general benefit. Two cases of pseudoleukemia treated by Krause ;) showed prompt improvement, while no result was obtained in 2 cases of lymphosar- coma. 1 ease of splenic anemia, and .'> cases of chronic splenomegaly. Jn no case did the treat men t have any serious secondary effect. 'Two methods of dosage are available. According to one method, .'5 to 4 Hol/knecht units of rays Xo. S Benoist should be applied over each glandular mass once a week unless contraindicated by the ap- pearance of dermatitis. According to the other method, smaller doses of I llol/knecht unit should be applied over each glandular mass three times a week. \\hen using either met hod exposure of the abdomen should be under- taken with caution. There is not ihe same special danger ot toxemia as in leukemia, but still the danger is great enough to make it desirable to ascertain the condition of the kidneys before making the exposure, and t he first one should be short . The distance and the strength of current and duration of exposure mentioned under the head of Leukemia (p. 1205; are suitable 1 here. The dilliciiltv "f differential diagnosis between lymphosarcoma and Ilodgkin's disease add- a further element to the uncertain prog- nosis which must be given in these cases. POLYCYTHEMIA T he results of .r-rav t real men t in this disease have not been decisive, but .-till .r-ray exposures of the splenic area have produced some im- provement and no accidents in 4 reported cases. MKDU'AL KLKITKICITY AXI) UOXTCKX HAYS A'-RAY TREATMENT OF LEUKEMIA The credit of first reporting the treatment of a case of leukemia !>y the .r-ray is generally accorded to Semi, but Pusey, Childs, Dunn, and others treated cases at about the same time. The treatment, therefore, is of American origin, hut it has been adopted in every country and has been made the subject of over one hundred articles by various authors. It was at once found that the majority of the cases improved in a most remarkable way if the .r-ray was applied repeatedly to the enlarged spleen, any enlarged lymphatic glands, and the long bones. The num- ber of leukocytes diminished from 200. 000 or more to the normal 4000 or 5000. and the general condition of the patients became so much better that they were called symptomatically cured. The spleen often dimin- ished to its natural size, but this effect was not so uniform as the effect upon the blood and lymphatic glands and upon the general condition. The treatment required frequently repeated application for several months or a year. The results were found to be permanent in only 1 case in about 15. As a rule, recurrence and death took place. Then 1 were bad effects in certain cases which were described on page> 1135 and 1205 Xevertheless. the .r-ray produces an improvement which nothing else ever did. and it seems to be the proper treatment for this disease. It is not unlikely that improvements in the mode of application may result in saving more lives than the 1 (i or S per cent, shown by the record to-day. Pancoast's method of application to the long bones instead of to the spleen has proved to be a step in advance. The close analogy between leukemia and sarcoma makes it seem |H)shible that leukemia also will prove to be incapable of permanent cure in the great majority of cases. This is a point which the 1 future will decide. It does not at all imply that the .r-ray is not the best treat- ment that we know of. The .r-ray ought to be applied in ('very case unless contraindicated. .r-Kay applications, in leukemia suppress fever when this is present, and also night-sweats, apathy, and anorexia. Asa rule, the cachectic appearance, the color and dyspnea, and insomnia all begin to improve 1 in-ide of two weeks. Albuniinuria. if present, rapidly disappears, but edema is sli i\ver. The .r-ray is more constant in its result- upon the myeloid than upon the lymphoid variety of leukemia. The author'- cases show a marvelous disappearance of the glandular -wellinu- following direct .r-ray application-, also very great improve- ment in the blood count and almost complete disappearance of the -plenic tumor. It should be noted in the latter connection that while a-ional direct application- to the spleen are usually required, they ot moderate do-aize. They are followed by diarrhea and a amount of depression la-ting a few day-. The author has had 1 ot permanent cure, but -everal of wonderful temporary benefit . ifn! i /ift cl inn \va- a hiiihly po--ihle causative factor in one fatal i which, however, there \va- a -tronu familial cause as well. Examples of the Results. Kr.-nise 1 reports the treatment of li case- iii myelou'enous leukemia: > ot these showed rapid improvement, reduction in the number ot leukocyte-, increased number of red blood- !' rlitl klJTi. \Vnrl,.. M;iY S, I 1 . Hi."., p. .X): iwirwr.l in HadilUIl, Sept. 1.' RONTGENOTHERAPY 1201 cells, increased globular value, diminution or complete disappearance of the splenic tumor, increased bodily weight, marked improvement In general health. The remaining case of myelogenous leukemia was complicated by hemorrhagic nephritis and was not influenced by the .r-ray treatment. Out of 4 cases of leukemia (myelogenous?) treated by Mclland, 1 3 were benefited by the .r-ray. Ilynck 2 has not obtained permanent results from the treatment of leukemia (myelogenous?) with the x-ray, but, at the same time, the condition of the blood and the spleen showed the improvements noted by other observers, and there was the same improvement in the general health. Rosenbach 3 believes that the reduction in the number of leukocytes is not due merely to the destruction of leukocytes and erythrocytes in the blood, but also to the migration of great numbers of leukocytes into the irritated skin and subcutaneous connective tissue. The products of the destruction of t he leukocytes probably have an inhibitor}- effect upon the production of leukocytes, According to Rosenbach, the .r-ray acts upon a symptom, not upon the cause, of the disease. He thinks it may even be that the great number of leukocytes is a defensive provision of nature in this disease. A case of splenomyelogenous leukemia was treated by Roth 4 by r-ray applications over the spleen and the long bones alternately. The primary effect of the .r-ray was to increase the number of white cells, which reached its maximum five hours after each exposure. The num- ber of leukocytes steadily increased from loo. 000 before treatment to :>7vOOO after the first month's treatment. From this time on there was a stead}" fall in the number of leukocytes, aided toward the last by the use of Fowler's solution of arsenic. After a year's .r-ray treat- ment, and a month after the arsenic had been stopped, the leukocyte count was normal, but the size of the spleen was not greatly changed. The primary increase in the number of leukocytes was accompanied by a great number of degenerate cells, principally disintegrating myelocytes, which in man} cases consisted merely of a network of iibrilhe. The amount of hemoglobin remained uniform at 70 per cent, during a whole year's .r-ray treatment, but promptly rose to SO per cent, when ai>eiuc was added to the treatment. The dosage of the latter was at first o Fowler's solution three times a day. and this was u'radually !o \~i t Imps t hive 1 nne- a day. mail" finds that .r-ray applications reduce the number of leu- and t hat t his is due part ly ig in the blood, the effect re>pond to basic dyes. 1 he marrow of 1 lie b< mes. 1 he effect of long .r-ray exposure M hree to fiv 1 Hriii-h Mc.l. Jour., July, !'.<).-,. - Wiener Med. \Vnch., June 10. 1005. ' Mi'mrli. Med. \\Mi-h.. May :;n. 1 !().">. p. 11).')."): reviewed in Radium, Sept. !.'>. l!)0.">. 4 Jour. Amor. Med. Assoc." Oct. _'(>. I'.'Oti 5 Briti.-h Med. .lour.. July 1 1, I'.MHi. 6 American Medicine, Dee. '_'. 1">. 7t> 1202 MEDICAL ELECTRICITY AND ROXTGEX RAYS of leukocytes, the lymphocytes being chiefly affected. There is no effect upon the number of red blood-cells or upon the amount of hemoglobin. It must be remembered that a sudden fall of perhaps 200,000 leuko- cytes is not an unheard of thing in leukemia without special treatment. Dock' has made valuable observations upon the clinical benefit and pathologic findings in cases of leukemia treated by the .r-ray. He found that the myelocytes rarely disappeared. (iramegna and Quadrone 2 and L. d'Amato 3 found that .r-radiation of the spleen led to a perceptible increase in the number of leukocytes, notably of lymphocytes, apparently by contraction of the organ. The blood of the spleen examined in 3 patients showed a large pro- portion of lymphocytes, some multinuclear myelocytes. a small number of multinuclear cells and of myelocytes and of nucleated red blood- cells, the number being superior to that found in the circulating blood. The serum had a slight agglutinative action, but no hematologitic or leu- kocytic action. The abnormal relations between the various forms of leukocytes persist even though their total number is so markedly reduced. Effect Not a. Bactericide One. The benefit in leukemia does not seem to be due to a bactericide action, for the ;r-ray is only weakly effective in this direction, and then we do not know that the disease is of parasitic origin. Nature of the Beneficial Action. The favorable effect of the .r-ray in splenic and lymphatic diseases (including leukemia and pseudo- leukemia) is explained by Krause and Ziegler on the ground that the application destroys the pathologic lymphoid tissue. Kdsall attributes the beneficial effect to an action upon the tissue ferments. The Nature of the Leukocytosis in Leukemia. Large lympho- cytes form 'JO per cent, of the total number of leukocytes; small lympho- cytes, 4 per cent., polymorphonuclear leukocytes, 4 per cent.; myelo- cytes, 2 per cent.; eosinophilc, 0.5 per cent.; no basophiles or eosino- phile myelocvtes (Mendelson and Soiidem). These observers found that on the da}' of death the large lymphocytes fell to 30 per cent., while the small lymphocytes increased to o3 per cent. A simple count of the number of leukocytes is not regarded as suffi- cient ; there should be also a differential count in cases of leukemia under :r-ray treatment. Ledingham 4 treated a case of splenomyelogenous leukemia with marked general improvement in the condition of the blood. The patient died of the grip, and a post-mortem examination showed that Malpighian corpuscles were absent from the spleen and that lymphoid tissue was very scarce. The most remarkable change consisted in the substitution of proliferating undifferentiated basophile myelocytes for the fully formed neutrophile cells usually found in the spleen in leukemia. The profoundness of the changes in the spleen caused Ledingham to recommend caution in the application of the .r-ray after the leukocytes had been reduced TO the normal number. Holdinu and Warreir' report temporary improvement in a case of 508. RONTGENOTHERAPY 1203 pseudoleukemia and in one of leukemia. The treatment was applied to the spleen, the enlarged glands, and the epiphyses of the long bones (elbows and knees especially). The blood showed the improvement reported by so many other observers. A careful examination of the urine showed an increased amount of uric acid and a high ratio of uric acid to urea during periods of active 1 .r-ray treatment, but Holding and "Warren were unable to trace any relation between the leukocyte chart and the urinary analysis, as above, or as regards the uric acid and purin excre- tion. The increased coagulability of the blood produced by x-ray ex- posures has been suggested as of possible value in hemophilia and other hemori'hagic conditions. 1 Effects of ;r-Ray Treatment Upon Excretion of Uric Acid in Leukemia. The majority of observers, including Pancoast, find that the amount of uric acid in the urine is increased by the- treatment, and regard the treatment as contraindicated if the amount of uric acid in a twenty-four-hour specimen falls after the .r-ray exposure. It is noteworthy, however, that another observer has arrived at a contrary conclusion: The reduction in the amount of uric acid in the urine, which is a consequence of increased oxidation and other vital processes, is regarded by Rosenberger" as an important indication of the benefit of .r-ray application in leukemia. If the amount of uric acid fails to be reduced ho thinks that especial caution should be used in applying this method of treatment. According to this observer there is a change in the ex- cretion of uric acid in cases of leukemia treated by the .r-ray. The amount is increased at first, then diminished, and then returns to about the normal. The excretion of xanthin is increased throughout the treat- ment, lie finds no such change in the urine in cases of pseudoleukemia or diseases other than real leukemia treated by the .r-ray. Chemic and Histologic Researches in Patients with Leukemia Treated by the .'/'-Rays (Lossen and Morawitz 3 ). They record a case of myeloid leukemia treated by .r-rays, and in which there was a return to the normal number of leukocytes at the same time that the excretion / ^* of uric acid returned to the average. (. * .-, = 30, instead of 13. as \uric acid it was at first.) These facts indicate a diminution in the activity of the tissues pro- ducing leukocytes. These authors insist on this retrogression of the leukopoietic functions. In certain case.-, however, the diminution in the leukocytes is not accompanied by a lowering of the uric acid ratio. Sometimes one can see developed in patients treated by the .r-ray an aplastie leukemia which is dependent upon the hypoplasia of the leukopoietic organs produced by the r-rays. Development of a Leukotoxin from .r-Ray Exposure. Milchener and "Wolff 4 found that .r-ray exposure of the spleen after removal from the living body produced a leukotoxin. An extract of such a spleen injected into a healthy animal produced a marked reduction in the num- ber of leukocytes, while a similar injection from a spleen which has not 1201 MKIHC'AL KLKH TKiriTY AND HC)XT(iKX KAYS been .r-rayed produced leukocytosis, increasing the 1 number of white blood-cells. Kxposure of living animals to the .r-ray produce's a reduction in the number of leukocytes, especially if the 1 blood-forming organs, the spleen and bone-marrow, arc 1 exposed. The fact that the primary effect is followed bv a renewal of the 1 number or eve'ii an increase over the original number of lenikocytes is taken by some authorities to indicate that the eftVc't is a direct one 1 upon the leukocytes and not a depressant one upon the 1 blood-forming organs. Other observers, like Iwan Hosen- stern, 1 consieler it due to the' effect upon the 1 leukocyte-forming organs, and that the number of leukocyte's is reduced not by their destruction, but by their greatly restricted production. The observations of Capps and Smith 2 show that serum from a leukemic patient who has been tivateel by the .r-ray produces a marked reduction in the number of leukocytes if .injected into another leukemic patient. This leukotoxin is strongest when the patient has responded best to .r-ray treatnu-nt. The action is selective, a (fee-ting mononuclear leukocytes more; than pe>lynuclear ones. Its repeated injection into another patient proeluces a kind of immunity, so that it is not followed bv as gre-at a reduction in the number of leukocytes as it e-aused at first. This same serum possesses marked leukolytic and agglutinating effects upon blood rn rilro. Phagocytosis is not affected by the serum from a patient who has bevn .r-rayed. Accidents Which Have Followed x-Ray Treatment in Leukemia. X-i'ni/ (Icrnidtilix over the spleen has bevn observed by so many operators that it seems as if some} special susceptibility must exist. One precaution which may be taken consists in the use of a screen of leather, wet or dry, or o mm. of aluminum, as a means of arresting the soft rays, which would otherwise 1 be absorbed by the 1 skin and set up dermatitis and which have no curative 1 influence 1 in leukemia. The position of the tube has a great deal to do with the e'l'fecl upon the skin. In some reported cases the .r-ray tube has been placed 10 cm. ' I inches) from the Mirface of the body. A burn was a natural conse 1 - qiience if enough .r-ray was applied to affect the deeper part-- of the spleen, -ituated two. three, or four times, as far from the .r-ray tube 1 . I he rays an- then four. nine, or six! ecu times as concentrated at t he skin irface as they w< mid be- a 1 t lie deeper parts of the spleen if t he mat ter of we have added t he effect of The anticathode should be placed he cutaneous surface in treating a fan' degree (>f penetration, ol vital importance, and either long ans of measurement as t he Sa bo ura ud inteiisimet ric unit s should be de- o apply the .r-ray even for what nis it he has no means It is like administering ked '' Solut ion of Mor- solut ion, of which a tea- >r hypodermic adminisl ra- iconscious and a tea- ir may know t hat wil h his p. loot;. RONTGENOTHERAPY 1 205 apparatus regulated in a certain way, so as to give a certain number of amperes with a certain rate of interruption in the primary current and a certain resistance in thetube result ing in a certain numlxTof milliamperes of secondary current, a certain number of minutes' exposure at a certain distance constitutes a desirable application. This knowledge he may have gained by experience or by the use of the quantitative or intensimetric systems so often referred to in this book. If he does not know the safe dose of the rays generated lie had better make the quantitative or inten- simetric measurements for the special cast; in hand. The theory that the .r-ray does not burn, but. rather an electrostatic or condenser con- dition of the air separating the .r-ray tube from the skin, and that burns may be prevented by placing the .r-ray tube at the proper distance (10 inches) to overcome this effect, is not to be relied upon to the neglect of proper dosage. Burns have occurred in cases in which this theory as to distance 1 has been exclusively depended upon. The cumu- lative effect of the .r-ray is always to be borne 1 in mind. Exposures which individually might produce 1 no visible effect might produce 1 bad burns if repeated day after day for a great many weeks. This is where the exact Knowledge of dosage is most, important. A case of Licbermeister's, a woman of sixty, showed cardiac weakness and additional swelling of the glands and elied after .r-ray exposure for llodgkin's disease. Pleurisy with effusion followed .r-ray exposure for leukemia in two of Quadrone's patients. Such accidents as these suggest caution in commencing this treatment upon a new patient whose degree of susceptibility is unknown. The toxemia which often follows .r-ray exposures in this disease, and which has been made the subject of admirable studies by Eelsall and others, is dese-ribeel on p. 1135. A case in which Pancoast made a single 1 radiographic exposure of eight see'onds preliminary to any therapeutic application showed pronounced and almost fatal toxemia, This con- dition appears to be due to the inability of the kidneys to remove the enormously increased products of destructive 1 metabolism. It may be guarded against in two ways: First, by making sure that the kidneys are in a healthy and active 1 condition before applying the .r-ray, and, second, by commencing with extremely small doses. Pancoast's suggestion as to avoiding the sple'en in the first few weeks or months of .r-ray treatme-nt for leukemia certainly tends to prevent the occurrence of extreme toxemia, though this is not its only object. In occasional cases of leukemia treated by the .r-ray a rapidly fatal fun ini/i has followed. Contraindications. The .r-ray comes into play especially in cases where abnormal cellular activity and development are- taking plae-e. and is contraindicated where profound depression of cellular life has taken place, as in the marrow of the long bones in pernicious ane'inia. I iixu t/irit ni"i/ of Ten dl act/ rih/ is a contraindication. Technic of ,r-Ray Application for Leukemia. Two principal methods have 1 been used for the application to the 1 spleen and the e i n- la I'ged glands: (1) Helot and ot hers in Europe make applical ions of -I or 5 1 1 ol /kneel it units oveT the en t ire surface of the spleen once a week tmi il stopped bv the development of dermatitis, whirh seldom occurs. To secure uniformity of eft'eH the tube is about s inches from the 1 skin and t lie surface is .r-ray ed m four .-ec! ion.-, i hrec benur protected \\ Itile one is exposed. The entire four sections are treated at the 1 same session. 1206 MEDICAL ELECTRICITY AND RONTGEX RAYS Belot has not observed any oases of toxemia from this method, hut in America it is regarded as extremely hazardous in an untried patient. Fatal toxemia has been observed from a single application of this strength in leukemia. There is not so much danger in the same appli- cation to the 1 lymphatic glands, but even here it is risky at the first treatment. ('2) The method of daily application of fractional doses of about \ to I Holzknecht unit over the spleen and lymphatic glands is usually safe, provided the urine has been analyzed and the kidneys found to be normal. The rays should have a penetration of about Xo. 7 Benoist, and an example of technic producing .1 II. is as follows: Muller heavy anode tube inches in diameter, 12-inch induction- coil with great self-induction; Caldwell interrupter, S amperes current, 2 ma. secondary current; Xo. ,s Benoist, 3j inches parallel spark-gup, 1 anode used; no rheostat resistance: distance from anticathode to skin 12 inches: an exposure of three minutes equals \ H. An exposure of six minutes under the same conditions equals 1 H. The daily dose varies between these amounts in different cases. The duration of exposure would be doubled if the treatment were given only every two days. Another example of dosage employs the same :r-ray tube and coil, a Wappler mechanical interrupter, 3 amperes of primary current, 1 ma. of secondary current, rays Xo. o Benoist, resistance 3 inches, 12 ohms rheostat resistance, no spark-gap, anticathode and accessory anode, connected distance from anticathode to skin 12 inches: an exposure of five minutes equals about 1 Holzknecht unit. Another example of dosage (quoted from Paneoast) employs a hard tube, resistance 4 inches, an induction-coil with a mechanical spring interrupter, and a secondary current of 1 ma. Four minutes' exposure over the abdomen at a distance of !) or 10 inches is a very mild exposure, but .-till was enough to cause profound toxemia in a case of pernicious anemia. Ten or fifteen minutes is a regular therapeutic dose em- ployed by Pancoa-t. Attention is to be called to the fact that he no longer makes the application to the spleen, not at the start, at all event-. The author'* technic is. to make a separate application to each glan- dular ma-- and to each knee and elbow and to the spleen from in front and from the side. One application is 0-inch spark. 3 ma., five minutes unfiltered. or ten minute- through ?> nun. aluminum at a distance of 10 inches, expo-ing an area ."> inches in diameter. One application is made to different area- three time- a week and in the first course of two or three week- each area has received one dose. Then either immedi- ately or after a two or three week-' intermission a series of half doses i- applied in exactly the same way. The .-tandard ( 'oolidge tube and a transformer are excellent for this work. Thi- tube can be run with the solid tungsten anticathode in- eande-cent if the '/, nia. i- not exceeded. Rontgenization of the Long Bones Instead of the Spleen in Leukemia.- This i.- a method adopted by Pancoasl 1 in the effort to find ;i tin an- of permanent cure instead ol temporarv benefit, and it is a method which seems to be less likely to be accompanied by distressing accident.- than he older met hod. : J.mr. Amor. M<-<1. Assnr., April 2.",, 19(is. RONTGENOTHERAPY 1207 The same daily applications are required, and the same quality and intensity of radiation, and the same distance and duration of exposure. The spleen is not exposed, and should be protected by x-ray metal if an x-ray tube is used without a localize! 1 . His method is to make daily exposures of both knees, for instance, for three days, which usually causes a reduction in the number of leukocytes, a fourth ex- posure being sometimes required. The different parts of the skeleton receive successive courses of exposure, even the dorsal vertebra being treated. After making a complete round in this way, the same process is repeated, and it may be that several rounds will have been gone through before any applications are made to the spleen. The result is a progressive reduction in the number of leukocytes and a return to the normal differential count. The spleen does not show nearly as rapid a change as when it receives direct applications, but, none the less, it gradually diminishes in size. Exactly when to begin x-raying the spleen is a matter of judgment in individual cases. The guiding principle seems to be that the spleen should not be x-rayed as long as it is practically a great mass of degenerate leuko- cytes, ready to break down under the x-ray, and cause toxemia from overloading the excretory functions. The theory assumes that the spleen does not produce these degenerate leukocytes, and that treatment of the spleen merely destroys them without reaching the cause of their abundance. The application to the marrow of the long bones is sup- posed to exert a curative influence upon the cause of the disease. The results of this plan of treatment are excellent. The applications should be made with very great regularity, and no ordinary excuse should be accepted for taking a vacation of even as long as ten days at any time until the blood-count is normal. Benzol as a Medicine for Leukemia. Koranyi of Budapest was the first to report upon the benefit to be derived from the internal use of this drug, and this fact has been verified by numerous other observers. A good mode of administration, suggested by Kiralyfi, is by capsules containing 7 grains of pure benzol and an equal quantity of olive oil. Two to ten capsules are taken after meals and the maximum dose is 75 grains (5 grammes) of benzol per day. The treatment is especially effective in cases previously treated by the Kontgen ray. The effect is chiefly that of reducing the number of leukocytes. Benzol is a drug to be used cautiously, and not for an indefinite period of time. Too great an effect causes severe or even fatal gastro-intestinal irritation. The Gauss Method of Rontgenotherapy for Uterine Fibromyomata. The use of hard rays filtered through o mm. of aluminum, with the tube rather close to the skin and the cross-tire principle to avoid re- peated exposure of the same cutaneous surface, has led to greatly im- proved results by Kronig and Gauss in the Freiburg Clinic. They re- gard practically every case of myoma as curable in five weeks, but con- sider operation preferable if enucleation is possible without causing sterility, or if there is probably cancerous degeneration or gangrene or if the bladder is incarcerated. 1 Their technic 1 ' involves the use of a water-cooled tube with a 5-inch principal bulb, connected with a 7-inch accessory bulb, which increases the stabilitv of the vacuum. Thev use a secondary current of 5 or 10 1208 MEDICAL ELECTRICITY AND RONTGEN RAYS milliumperes sent through the lube in a succession of flashes by a rhyth- ineur. The tube is enclosed in a cup-shaped shield of lead glass, the orifice of which is covered by a screen of aluminum 3 mm. (or -J inch) thick. The .r-ray is applied to thirty or forty different areas of the ab- domen, front and back. Kach area is about 1 inch in diameter, and upon it is laid a Kienbock strip of photographic paper to test the dose applied. The skin immediately around this area is protected by a thick lead disk with a hole 1 inch in diameter, and overlapping the edges of this are two L-shaped pieces of sheet lead, J,-inch thick, protecting a region of 1 foot square. Overlapping the lead is a protection of .T-ray-proof fabric cover- ing the entire trunk and head. They place the tube very near the skin to bring the anticathode as near as possible to the deep lesion, relying upon the thick aluminum filter to stop the rays which would chiefly affect the skin: and also upon the fact thai the dose applied to the deep- seated lesion is divided among many different skin areas. Nevertheless, as measured by the photographic strip in contact with the skin, the dose iii. M-'l. Water-c tungsten target tul>r for ( lauss I rent incut work (Baker A'-ray ( 'o.). applied by these operators at each spot appears to be several times the ervthema dose as measured by the Kienbock sensitized paper. The reason this large dose does not produce a dermatitis in each place to which it is applied is because the thick aluminum filler has stopped all the ravs which would be entirely arrested by the skin and permits the pas nun. ol aluminum readies t he cavity of t he uterus a n< I one-hall when 1 inn:, are used. I In 1 .' ra\ converges upon the uterus and ovaries from many dif- ferent port ion- of t he surface. Kronig and ( lauss give a complete t reat- ment at a -mule -r-- ion. la st mu 'perhaps three hours and requiring per- hap- -e\i n dilieivnt .r-rav lube-. This is repeated every three weeks RONTGENOTHERAPY 1 209 until permanent amenorrhea is produced, and in 300 cases or more they have secured a complete cure. The cases in which amenorrhea is not secured are apt to have a return of the fibromyorna. (!. K. 1'fahler and John A. MKilinn, 1 however, consider the effect upon the ovaries un- necessary and report a couple of cures by the .r-ray treatment of the uterus alone. This method of very heavy dosage, even with filtered rays, is not to be rushed into without gradual, careful testing of the effects of such appli- cations. Necrosis of the intestine lias been reported in rare instances and also dermatitis. Kronig and (iauss apply mesothorium and radium internally in many cases. The method described marks a very great advance in Rontgeno- therapy, but requires great study and experience. The author's tcchnic is to divide the portion of the. abdomen below the umbilicus into four sections and the sacral region into two lateral halves. For each application one of these areas is exposed and the sur- roundings protected by sheet lead 4 mm. thick. Kays of (5-inch spark, 70 kv., 3 mm., five minutes unfiltered or ten minutes through 3 mm. aluminum at a distance of 10 inches are applied to three separate areas one day and to the other three two days later. This is a complete treatment which may have to be repeated two or three times a year. It may be combined with intra-uterine applications of radium. EPITHELIOMA The form in which the skin is not adherent or fixed to the underlying tissues is almost certain to be cured by .r-ray treatment. This form is frequently met with near the inner angle of the orbit, and is microscopic- all}' the same as the intractable form occurring on the lip. The first form may exist for years without amounting to very much locally and without glandular involvement, and may be radically cured by caustics, excision, or the .r-ray. The second form is clinically an entirely different disease. After reaching a certain stage it involves the tissues deeply, produce? glandular metastases, has a tendency to destroy life, and is seldom completely cured by caustics, excision, or the .r-ray. The first type occurs upon a dry cutaneous surface, the second usually at the nmcocutaneous junction at one of the orifices of the body. The first may be called cancroid, as distinguished from the true cancer of the second type. In the first type, or skin-cancers, .r-ray treatment is practically certain of success and gives a better cosmetic effect than any ot her kind of t reat ment. Recurrence after surgical excision of an epithelioma of the face 1 is frequentlv due to the fact that the surgeon has not gone beyond the in- fected urea, being influenced by a desire for a cosmetic effect and to leave as lit lie deformitv as possible, ('uretage, the galvanocautery, elect rolvsis. or mercurial cataphoresis also are liable to leave infected t issue for the same reason. The tissues which are no i actually destroyed are sources of trouble unless, the process has been applied beyond the infected area, and this it is often impossible to do without leaving undue deformity. The .r-ray i- noi open to any such objection. It can be applied to a wule enough area to include all the infected tissue and some of the surrounding sound tissue in a case of epithelioma of the face, and in a strength suitable to the cure of epithelioma it does not de-troy 1 Aincr. Jour. (>l>-trt. :tnd Pis. <>f Wi.nicn and Children, vol. Ixxvii, No. '2. 1'JIT. 1210 MEDICAL ELECTRICITY AND RONTGEN RAYS neighboring sound tissue. It is an ideal method from a cosmetic stand- point, and for the reason above stated a case of epithelioma of the face cured by the .r-ray is much less liable to recur than one treated by the other methods mentioned. Some caustics, like pyrogallic acid, have the property of destroying exposed epitheliomatous tissue without injuring the neighboring sound skin and arc excellent from a cosmetic point of view. There is no such deformity as results from surgical excision, but there is not the same freedom from recurrence, which is the chief advantage of :r-ray treatment. According to Robinson, the .r-ray as an exclusive treatment is most likely to be successful in the variety of cutaneous epithelioma known as rodent ulcer and in some cases of superficial prickle-celled epithelioma. He also regards certain cases of rodent ulcer, especially those of the crateriform variety, as incurable by the .r-ray or any other known means. '' Hard, firm, elevated epithelial margins must be made more vulnerable by injuring agents, such as caustics, before the .r-ray is applied." These are the cases in which, if the .r-ray alone is depended upon, a more severe reaction than usual must be produced. The high-frequency spark from a metal electrode is an excellent ap- plication for epitheliomata which do not yield readily to .r-ray treat- ment, or which, from their very appearance', we know will probably not do so. It has been referred to elsewhere as an adequate exclusive treat- ment for non-malignant keratoscs and for epitheliomata where the dis- ease is entirely localized. It does not destroy the disease beyond the point of application and necrosis and, therefore, in certain cases it would not prevent recurrence unless the .r-ray were also used. Microscopic Changes in Cancer Under ,>r-Ray Treatment. Stewart 1 examined tissues from an epithelioma of the wrist of traumatic origin. The important changes found were fatty degeneration and vasculari/ation of the epithelial pearls; leukocytic infiltration and carious degenerative processes leading to destruction of tissue; bodies indis- tinguishable from Plimmer's bodies multiplying as the epithelia de- generated. The histologic changes in a case of epithelioma of the gum and hard palate treated by myself were chiefly those of leukocytic infiltration. The disease was not cured in this case, however, only held in check. Pusey has found that an effect is produced upon the morbid epithelial cells themselves, and consists in a primary stimulation followed by de- generation, absorption, and disappearance, and their replacement by connective tissue derived from the healthy stroma. Endarteritis is produced in the smaller vessels in immediate relation with the tumor. Effect of Alcoholism.- Alcohol used in excess is injurious in cases of epithelioma, especially in elderly persons, and interferes with the ellic-icv i if ./--ra v t real nient . ~ Application of a Caustic Before .r-Ray Treatment of Epithelioma. - A saturated solution of chlorid of /'me is an excellent caustic for removing part of a growth or for rendering an indurated growth more susceptible to .r-ray treatment . It forms a dry eschar, but, has no selective act inn upon t he diseased tissues, such as that exerted by pyrogallic acid. rlical .Iniininl, Dec. L".t, I'.XIti. RONTGENOTHERAPY 1211 A desirable technir is a single "massive" of 3-inch spark, ma., five minutes with l ; mm. inch aluminum at a distance of 10 inches. Flat Surface Forms of Epithelioma. A case of this kind was suc- cessfully treated by the author at St. Bartholomew's Clinic. There was an ulcerated surface, looking like the sluggish raw surface some- times left by a burn, over the trapezius muscle on one side of the neck. The patient was a man sixty years old, and this had begun as a small pustule and had gradually extended until it measured 1 inch by 2 inches. Applications were made by a (Ireen and Bauer heavy anode rr-ray tube G inches in diameter, enclosed in a Friedlander shield and excited by an 8-inch induction-coil with a Caldwell interrupter and a primary current of 4 amperes. The rays were of penetration Xo. 6 Walter. Exposures of two minutes three times a week, at a distance of 9 inches, were made Fit:. S23. Euitholicnia of forehead cured ?2. Epithelioma of forehead and sc before Rontgon ray treatment. until a slight reaction occurred, and were then reduced in frequency. It took about seven months to effect a cuiv in this case. The case shown in Fig. 82 i was peculiar. Following a scratch received when the patient was a girl twelve years old an indurated and ulcerated spot had persisted for fourteen years. This disappeared under .r-ray applications made with the tube in a locali/ing shield (Fig. S2t>), with the face further protected by sheet lead, through which a hole was cut considerably larger than the lesion. A piece of adhesive plaster fastened the lead to the skin around the lesion, the latter being left en- t irely exposed. During I lit 1 course of a couple of years there were recurrences and repeated .r-ray treatment and. finally, surgical excision, rnfortunately there was no microscopic examination. There has been no recurrence. Epithelioma Near the Ala of the Nose. The following was such a 1212 MKIMCAL KLKl'THU'ITV AND KONTCKN KAYS case, the patient being a lady sixty-seven years old. whoso father had suffered from a similar trouble, resulting in the loss of the entire a!a of the nose. Hers began three years ago as a small abrasion and growth under the right eye and which gradually reached the condition present when t the n lea t of an a linond RONTGENOTHERAPY 1213 r isz. si.' (j. I cch n ir of Roiitjii'iiotherapv for enit helioma of face. Tube in a locali/ii hit-Ill; perforated sheet of .r-rav metal securelv fa-teued to the surface \>\- adliesi Kpit h> liotna of nipple which had fe-i^ted radium t n 'at me tit. Aliandoned .r-r i\ a < Ice]) ulcer. The LiTi)\vth was freely movable and t here \va> IK > pain, hut tnerelv an itcliinsj and uncoinfortank 1 sensati.m. [here wa> a swcllin": 1214 MEDICAL ELECTRICITY AND RONTGEN RAYS and redness of the malar region. There were no glandular involvements or affection of the general health. The only treatment was by four applications of the .r-ray each week from October 1. 11)04, to March 1, 1 !(>.">. For most of the applications a Morton treatment tube was used, which is made of lead-glass perfectly transparent to light, but opaque to the .r-ray this is the kind known as flint glass, and is the "paste'' of which imitation diamonds are made. A piece of ordinary glass ^transparent to the .r-ray) forms the end of the prolongation through which the .r-ray passes from the anticathode. When properly excited this tube is filled with a beautiful blue light, brighter in front than behind the equator formed by the plane of the anticathode. The Fpithcliiitiia near lulu- of cur. Had boon unsiircpssfully treated 1>y radium and abandoned .r-rav t rent incut after three applications. ry "crown" or soda ijass forming the end of the prolongation : : -'.MI- the familiar greenish fluorescence of the .r-ray lube. With the >scope ;t >harply deiineil circle of liu'ht is produced by the .r-ray from thi- prolongation. It i- covered with thin rubber and held directly in contact with t he part to he t rented. A liquid interrupter of either the < - in type or the \\'elmelt was used with a 12-inch coil, with lai'ife M-if-ii . iction m the primary coil, and a prunarv current oi 41 amperes, the iv.-i.-t atice of the tube beinc: '_' inches and the radiometer (Tousey's) '_'. To avoid overheating the tube it was applied for a num- ber ot ,-hort exposure>, aggregating from three to five minutes at each session. The tubi was ln-ld in iiosition bv hainl. The last month's RONTGENOTHERAPY 1215 treatment was with a Miiller heavy anode tube, No. 13, and a local- izing shield with a hard-rubber prolongation, the end of which (cov- ered with thin rubber) was im- mediately in contact with the face. The anticathode was thus at a distance of 10 inches from the part to be treated. The resist- ance' in the 1 tube was 2 or 3 inches, the radiometer 3 or 4, and t In- duration of exposure six minutes, with the 1 same primary current that was use'd with the Morton treat- ment tube. Whenever a certain reaction, indicated by moderate redness and some itching, was established, the treatments we're 1 made somewhat weaker. The- ulceration was com- pletely heale-d in two months and a half, but the 1 induration was more 1 persistent and the treatment was not completed until the first of March, l!)()o. At that time the ' surface 1 was flat and fle'xible; there Fi -- R20 -~ Epithelioma of nose, cured by , , ,, jr-rav treatment. was some redness as a result ot the treatment Three years after the cessation of treatment there had been no recurrence. Several hundred similar cases have been treated in different parts of the 1 world and with great suc- cess. A Case of Epithelioma of the Gums and Hard Palate. The patient shown in Fig. s3() had been see'n by Dr. Brewer, who had re-moved a section for microscopic examination, and who consiele'red the 1 case 1 as unsuitable for operation. She was se'venty-five years old and had a jxisitive 1 family his- tory of cancer. The trouble 1 started four ye'ars before 1 in e'onsequence of irritation from a set of artificial teeth. When first treateel. August 14. 1!H)4, the upper gums and ro.if of the' mouth and the' inside of the chee-k presented the apjx-ar- ance of a bright purple- mul- berry. Kach little nodule- was shiny and translucent. There 1 was comparatively little pain. The treatment consiste-d in applications from a heavv tanret (iunde- 1216 MEDICAL ELECTRICITY AND RONTGEN RAYS Inch tube in a localizing shield with a cylinder I 1 , inches in diameter; the distance from the anticathode to the diseased surface being from *! to 11 inches. An S-inch induction-coil was used with a Caldwell interrupter and a primary current of 4 amperes. The resistance of the tube was equal to a 2i-ineh spark-gap and the rays were No. 5 Benoist. Kaeh part of the diseased tissue received an exposure of from fifty sec- onds to two minutes at each treatment, twice a week. There was more pain after the treatment was begun than there had been before, but this disappeared as the case progressed. A pathologic examination, made October C>, 1904, after two months' treatment, showed the same general type of epit helioma as in June, two months before treatment was begun, but more epithelial pearls and a mild acute inflammation, the whole tissue being infiltrated with pus-cells. Six months' treatment kept the growth absolutely in check, but did not cause any part of it to disap- pear. made the patient more com- fortable and better able to take all kinds of food except those re- quiring mastication. She had gained 21 pounds in weight. She became discouraged bv the expense of the treatment and of coming to the city from her country home, and thought perhaps that she would get along equally well without anv further r-ray treat ment. Reports during the ensuing year were to the effect t hat her niout li had got I en into terrible condition, and she died many months alter the ./'-ray treat- ment was stopped. Cancer of the Lip. This is a type of epit helioma which is very different from that occurring upon ot her part s of i he face; .r'-ray t real - ment should not be depended upon as the sole method of treat- t re; 1 1 men) a \< me. Epithelioma of the Eyelid and at the Inner Canthus. Another class lit' c;ises i- shown in Fig. SMI, a seventy-five-year-old patient at St. Bart holon lew's ( 'lin ic. with a deep! v nice rat ing epit helioma of the lower lid: r-rav treatment \vas emploved for a period of about a Year and . but it did not succeed in healing the ulceration. In fact, this . '. became uTadiiallv larger during the course ot treatment. Had en in a region where more vigorous treatment was permissible a cure would probablv have been effected, although the patient's age and surroundings were unfavorable. \nnt her unfavorable chiss of cases was illustrated by a St. Bartholo- mew',- patiejil \\nli an ulceration on the side of the nose near the inner RONTGENOTHERAPY 1217 canthus. The surface \vus smooth and red and level with the surround- ing skin. It was adherent to the underlying tissues and there was evi- dence of deep-seated involvement; .r-ray treatment continued for about a year seemed to hold this in check, but did not result in a cure. Here again the pat lent was old and poor, and the region was one in which vigorous treatment was contraindicated. In cases like the two last .r-ray treatment is useful as a palliative means if an operation is impracticable, and also before and after opera- tion as a means of preventing recurrence. It is going to an extreme to say that .r-ray treatment is not indicated in epithelioma where the skin has become adherent, but it is certainly true that there is a very much greater prospect of success where this is not the case. Cancer of the Penis. According to Robinson, 1 the rr-ray has bene- fited or even cured certain cases, but in other cases he says it has has- tened the growth, and its long-continued use for a course of twenty, thirty, forty, or even a greater number of treatments wastes time and may reduce the possibility of success from an operation. There is no doubt that most cases of cancel- of the penis should be promptly operated upon surgically. The .r-ray used afterward and com- menced oven before cicatrization will greatly increase the patient's chance of escaping from recurrence. If, for any reason, it is desired to avoid an operation and try the .r-ray as the sole treatment, the attempt should be given up if there is no evident improvement in three or four weeks' time. The testicles should be protected by sheet lead, and in most cases the entire penis and both groins should be exposed. RADIOTHERAPY WITH THE TUBE IN DIRECT CONTACT WITH THE BODY The theory that the x-ray itself does not cause radiodermatitis, but that the latter is due to a condenser effect, and may be avoided by placing the tube in contact with the surface, has found its principal adherent in Dr. (loysor. His records show a series of about ;">()()() appli- cations with the tube in contact without a burn, but in a personal state- ment to the author Dr. (Joyser says that he has had more than one burn due to the patient not holding the tube in perfect contact with the sur- face. His patients have sometimes made this mistake in order to lessen tin- feeling of static electric discharge winch they experience, especially when the vacuum of the tube is a little higher than usual. It should be noted, however, that those applications were with a small special t ube, t he Cornell t ube (see p. 12 lit i, and that t IK' doses were small, and that there seem to have boon no comparative experiments with the same doses to prove t hat t hov would have produced irrif at ion if the tube had been at a distance. It is a fact also that Dr. (!eysor does not apply larii'o ./'-ray tubes to the surface, either for treatment (as in cases of leukemia) or for radiography, and that ho does not produce burns. The same is true of other operators. For instance, in the author's service at St. Bartholomew's Clinic not a single burn has boon produced from the discovery of the .r-ray to the publication of this book, and the tube has been at a distance from the surface in most cases. The condenser theory supposes also thai with the tube at a certain distance 1 Xi-\v York .Mod. Jour., JVr. 2U, 1<)()<>. 12 MKDICAI. KLKi THICITY AND RONTGEN HAY; fn>m the surface there is hnnuiiiity from burns, but 1his again is to be viewed in the light (if cases of leukemia, in which treatment begun by 1 )r. ( ieyser has been con t in tied at the same distance bv other operators, advi.-ed by Inn;, and hum.- ha\'e been produced. 1 lie au'hor feels niai the condense]' tlieor\' of the origin of .r-rav dermatitis has not been proved, but that it probablv contains a certain element of truth. He believes it exceedingly dangerous to say that a burn cannot be produced with the tube in contact or with the tube at a certain distance ("far enough to avoid condenser effect";, lie be- lieves that correct dosage is just as important in this as in any other application of the ./'-rav. He hope.-, however, that tins method may prove a means of applying correct doses without the irritation which the-'- have sometimes pioduced when applied from a distance. TECHXIC OF DIRECT APPLICATIONS The tube is of lead-glass, except at a window of soda-glass, where it is to be hel' 1 again-t t lie surface. Different tubes have been constructed for this purpose, begin- nim: with Cossar's and followed by Morton's. Pif'fard's, Caldwell/s, Tou>oy's, and. mo.-l recently, the Cornell tube. Most of these can be ap- ! l>:i<-k fnnn tho plane 1 '.- ' ; : ce of the .-kin or introduced inlo i he cavities or held cc. Then ihei'e should be mentioned the dii'i'erent uni- Tesla's tube to Stern's, all of \\hich are intended i ion. ' : . choice lies between Toil-ey's lube and the Cornell , by 1 he same manufacl ui'ers u]on t he i-ii ion-, \\-iiich (he aul hot 1 ' hinks de- .* Rfiy Treatment Tube '!';-. '-''. > - The bulb i- of prol t ion, . -. The atiod' and cathode ] " !|1 - are ' ; i . ., I I'tM dis- . i i hat RONTGENOTHERAPY 121!) Ilic Tou-ey ; ube has a bull) 1 inches in diameter and ;i h";ivv antlcathode. These features lit it for .-landing hca\'\' currents for a sufficient lime for any ordinary radiograph, where as small an area of illumination as tins will cover is sutlicient. Jt holds it- decree of vacuum better than the lighter Conicl! tube. \\'hen employing the Tousey tube one is not confined to lomr, weak applications, of five, six, or more minutes, but may make an a]) plication of t he same amount of a ray in one or t \vo minutes or le-s if desired. 'This tube may, therefore, be run with a Caldwell in- terrupter and other interrupters, with which we .-hall sec the Cornell tube becomes overheated and loses its vacuum. Dosage With the Tousey Treatment Tube in Contact with the Surface of the Body. The anticaihode is only 2] inches or ]() cm. from the surface, and so, when the tube i- directly in contact with the surface, the measurement of dosage by the Sarbouraud and Xoire tablets becomes a little different from the usual method. Ordinarilv the test tablet is placed half as far from the anticathode as the surf a PC to be treated, and on the principle of the square of the distance the skin is exposed to an intensity four times less than the test tablet. \Vith oniact treatment tube, however, the test tabl-t and the skin are at ihe sain distance and receive the same imet:-ny of radiance. A MI ex po- lire to produce i in i /' in \ ':- >: ' :":.''.' I and Xoire radi- .. ' ' ir .,'.>!, \ . out Al II. if ti -kin i- i '/.ice as far : ;n icrii hod,;-. Inn ' :' : ! co-'/a--; ent the same "; : lie (-1 >]or of the i I he dose del 1220 MEDICAL ELECTRICITY AND KONTGEN HAYS the soda-glass window, glass prolongations insulating the electrodes, the turning of the latter away from the patient, and the insulated glass handle. The differences are lighter construction, contributing to easy handling, hut detracting from ability to stand the current. Dr. deyser's originality lies in the routine use of the tube for contact treatments, with the claim that the same amount of .r-ray will not pro- duce a burn in this way, as if the tube were at some distance and a condenser effect were thereby established. There 1 are certain technical details which must be observed in the use of the Cornell tube. These are consequent upon the small si/e of the bulb and the lightness of the anticathode. Currents of the strength ordinarily employed in radiography or radiotherapy almost imme- diately cause the tube to break down. The anticathode becomes over- heated and the vacuum falls below the useful limit. There are several way.- in which this can be prevented and the tube kept in working order long enough for the therapeutic effect. If the \Yehnelt interrupter is used, it is found desirable to expose a very great deal of the platinum point, so that a heavy current of lo amperes will be allowed to flow, but with very slow interruptions. The rheostat ma}' be used in securing this effect. Kach of the slowly repeated impulses produces a flash of .r-ray, and an application of about live minutes is required when the tube is excited in this way. Another method, which will usually be found preferable, is to use a mechanical interrupter, such as the "Wappler interrupter, adjusted to give quite slow interruptions and a current of about 2 amperes. About five minutes' application is desirable in this case, but the quantity of .r-ray bears such a direct relation to the number of interruptions per minute that even a very slight difference in the ad- justment of the interrupter will necessitate a decided change in the durat ion of the exposure. Any technic is suitable which enables the proper quantity of x- radiation to be applied without overheating the tube. CARCINOMA The cases in which .r-ray treatment may produce a cure are prac- tically limited 10 those of the breast and other external parts with- out internal glandular involvement, and the more nearly the tumor roaches in microscopic structure the border-line between a ma- lignant and a benign growth, the greater is the prospect of complete Effect of rr-Ray Treatment in Cancer. The mode of action of the ./"-ray in the treatment of cancer has been studied by J.yle. 1 lie has ahvays noted an abundant discharge after the applications, and this rtre is alkaline and crystalli/es when exposed to the air. lie - this as an external evidence' of a cln-mic effect, which accounts he toxemic symptoms v.hidi sometimes follow an application. il'- thinks that 1l:is cliemic product is dangerous and sometimes fatal, ! .r-rav treatment should be limited to cases in which drainage can be < -'ablished. and that it should not be used in deep-seated caii- ccrs, Apropo- of t] is, the present author believes thai substance's analo- gous; to toxin- or antitoxins are produced by exposure of a cancer to the 1 Me-liral Hfvonl, Julv 1."), 1(10.1. RONTGENOTHERAPY 1221 .r-rny; that the production and absorption of those substances in large doses causes toxoinic symptoms; but that in proper proportions they have a curative effect upon cancel 1 . 1 have many times seen a beneficial effect upon cancerous involvements which from their position (as to depth or otherwise) could not have received enough radiation to produce a direct effect. It is true enough that a cancer which forms a flat, open, and freely discharging ulcer may properly receive larger doses of the x-ray than a malignant tumor without ulceration. Perthes 1 has noted that the cancerous cells fuse into a uniform pro- toplasmic mass with an irregular outline and that their nuclei stain less and less well. Leukocytes and connective-tissue cells penetrate the mass; later the cancer cells are seen imprisoned and isolated in the meshes of connective tissue and undergo degeneration and absorp- tion. Ellis 2 thinks that the .r-ray produces necrosis of both the parenchyma and the stroma of the tumor, accompanied by proliferation of elastic tissue and obliterative endarteritis. According to Schwartz, the .r-ray causes a decomposition of the lecithin, which is more abundant in rapidly growing cells, like those of neoplasms and like the normal parenchymatous cells of the testis. and in this way has a destructive effect upon these particular cells in doses which do not affect other healthy tissue cells. Mouse tumors taken out, x-rayed, and put back, grew. When the mouse was x-rayed after the tumor was taken out and then put back it did not grow. The theory is that the x-ray caused lymphocytosis which inhibited the growth of the tumor, but further radiation would lessen this inhibition. 3 The fact that serum from a part which has been strongly x-rayed may produce symptoms of an x-ray dermatitis if injected into a part of the same or another animal which has not been irradiated is sug- gestive of a cliemic effect. It may be that an anticancerous serum could be injected deeply into the substance of a malignant tumor and produce a greater degree of benefit in the depths than the rays weak- ened by absorption in passing through the superficial parts of the tumor. This could be done without exposing the patient himself to the x-ray. From the diversity of opinion among the above and many other authors it is evident that we do not know the exact way in which the x-ray affects the cancer cells, whether by a direct action or by an electro- lytic process. There seems to be no doubt, however, that cancer cells have an especial susceptibility, and that under favorable circumstances they may undergo degeneration and absorption without ulceration or destruction of the mass of tissue making up the tumor. ( 'ases of cancer have died suddenly quite a long time after having been treated with a great deal of benefit by the x-ray." 1 'Thirtycroud ('ons of the (icnnaii Siiruiral Society, Berlin, June li. r. to: ; - Ainrr. .lour. Mod. Sciences, Jmmary. P.'enl>eriiT. Second IIoiii-cu ( 'onure-s. I'.'ii.",. 1222 CARCINOMA OF THE BREAST The technic employed I >y 1 he author is (i-incli .-park. ~.\ ma., filter of '.\ nun. aluininuin, distance 10 inches, ten minutes to each area, re- peated every three or four weeks. The absorption by the tissues is such that of a surface dose at X inches from the ant icat hode and with .r-rays corresponding to a 9- inch spark gap. only one-seventh reaches 4 inches below the surface. 1 Bo^s' standard dose is 20 x Koenig (( iauss modified Kienbock scale), and this is produced in a Coolidge tube, a modern transformer, S-inch distance, 4 mm. aluminum filter. 9-inch resistance, 25 ma. minutes. For a cancer of the breast with, of course, possible involvement of the mediastinal. axillary, and supraclavicular glands as well as other neigh- boring structures, Boggs applies such a dose to each of the following areas: (1) Three or four areas of the anterior chest wall and extending toward the axilla and liver ; ( 2 ) the three or four areas of axilla and one area of the side below the axilla; (3) three or four supraclavicular areas; (4j supra- and subscapula; (o) one or two to mediastinum from behind, Fie. S.'j4. Recurrent carcinoma of the male brea. t cured (no recurrence in five years) by ar-r;iv treatment . between the opposite scapula and the spine; ((>; four to eight areas of the opposite; (7) epigastric. A second course is given four weeks later. While each of these many areas is receiving the .r-ray, all other parts are protected. There is a cross-fire effect. In a ureat many cases of recurrent cancer of the breast there is contraction of the axillary cicatrix which binds the arm more or less to the -ide and make- it difficult to apply the .r-ray to the axilla. It ha- been succe-sfully accomplished hv the present author. The .r-ray i liplicd from in Front while 1 he ell >ow is drawn back as far as possible ; and fV'im behind while the elbow i- drawn forward across the chest. way every part of t he axilla is either exposed direct ly or through thi'-k obstruction of fle-h in cases where the elbow cannot be d ironi the -ide more than a few inches. . of course, i- very <-onvenient ly applied even in the most ext - df axillary contraction and ulceralive neoplasm. nf a case of carcinoma of the ma le breast referred to t he author bv IV. K. \Y. Hall. I operated upon the original growth in one breast, removing a tumor which the pathologic examination showed to le carcinoma, but with an appearance which did not indicate the great est degree of malignancy. There was recurrence in t he ot he! 1 breast within a year and .r-rav treatment was at once begun. Mild applica- tions were made three times a week until the development of a mild erythema, and then the treatment was kept up sufficiently to keep the skin slightly reddened. The tumor made no further headway from the time that the .r-rav was first employed, but there was no perceptible diminution in the size of the tumor for about nine months. Then it bewail to improve, and in two more months not a trace of it remained. The region of the original growth was .r-rayed at the same time as the other, but never showed anything but a somewhat suspicious appear- ance. It is now five years since the cessation of treatment and there has been no return of the growth. Figure S35 is of a patient referred, May 12, 1905, by Dr. Clement, of Cleveland. The patient was a lady sixty-four years old upon whom the surgeon had five years previously performed an amputation of the breast, with removal of the pectoralis major and the axillary contents. The microscopic examination showed that the disease was carcinoma. There had been a recurrence in about two years which was considered inoperable, and for which x-ray treatment was applied for twelve months Fit:. V!."). Inoperable recurrent carcinoma of 1>re:i-t held in check for lliree veurs ti\ with a great deal of benefit. Some tune had passed since then, and asse appearance ot the breast and axill i and enormous swellum' of the arm. Measur 1224 MKDUAL ELKITRICITY AM) K(")NT(IKN RAYri made at this time showed an increase of 2 inches at the wrist, of 3 inches in the forearm, of 21 inches at the elbow, and of 2\ inches at the arm over the circumference of corresponding parts of the other arm. A fluoroscopic examination showed that there was no intrathoracic tumor. This case never showed anything resembling a toxemic reaction from the x-ray applications. An example of the technic employed is found in the following: Miiller Xo. 13 tube, induction-coil 110-volt direct circuit, Wehnelt interrupter. 5 amperes primary and 3 ma. secondary current, resistance 21 inches, radiometer Xo. (j, exposure five minutes at a distance of 12 inches from the anticathode, limited to an area 8 inches in diameter by a localizing shield with its 3-inch diaphragm. The exposures were sometimes divided, so that the axilla and the breast received exposures like the above separately. High-frequency currents were applied to the arm, breast, axilla, and side of the neck from ultraviolet ray vacuum electrodes. Treatments were given three times a week, except for a couple of months in the summer, and for two years the disease was held in check and the patient was well and happy and attending to her usual social duties. The disease in the meantime seemed to have lost its malignancy, There remained some fulness of tissue at the anterior fold of the axilla, but there was no longer any ulceration, and the arm was much less swollen. Then came a period of gradually increasing pain in the region of the other shoulder-blade. There also developed a small abrasion at the anterior fold of the axilla that was quite painful. The great swelling nf the arm never returned, although some swelling continued throughout the entire course of the disease. While no local appearance of malig- nancy was apparent, it was evident that her general strength was failing, and the patient died in September, l'.M)7. This was seven years after the operation, and for the last five years of her life x-ray treatment had kept her perfectly comfortable and an active member of society in spite of the presence of an inoperable! carcinoma. There were a great many times when the patient forgot about the trouble, and really the only annoyance for months at a time 1 was the swelling of the arm. Another case was referred by Dr. Hissell. The patient was about fortv years old. and had been operated upon two years previously for a carcinoma of the breast, which she had concealed until it was too late to hope for anything like a cure. The poor lady also concealed the fact of a recurrence in the other breast until it formed a larire ad- herent mass and her general condition precluded operative treatment. '1 here was also recurrence in the cicatrix on the side which had been operated on. 1 he pat lent had a verv si ran lie v a so neurosis, which at the ' in-pection <>f the case and before the x-ray was turned on caused hest to become a fierv red like the most violent blushing, kepi her face covered with a thick veil, so that '!' the deep blu-h suffused the face also. At .- h lira dually became less marked over 1 he chest, and finally, i| lite accustomed to ihe presence of the oper- . :' ceased to occur. At a subsequent period, however. : ' -uriieoi . v r 'i was consulted in regard to a conipll- rei ini of thi- vivid blu-h covering the entire ;' the x-rav had been u-'-d the natural supposition RONTGENOTHERAPY 1225 was that the redness he saw was the first symptom of x-ray dermatitis; and from its extent and vividness the doctor thought that there, was going to bo a severe burn. Tin's appearance, tive. The treatments in were of the same kind >f course, was decep- this case as in the case 1 previously described. The first treatment was followed by a febrile movement, 102 F., with some prostration. This was at- tributed to a temporary toxemia caused by the x-ray exposure. It did not occur again during the course 1 of treatment. This patient did wonderfully well for a time, the recurrent tumor in the breast diminishing one-half in size and the original cicatrix assuming a natural ap- pearance. The patient's general health was greatly improved. Then came a complicating pleu- risy, with effusion, and a rapid illness, which terminated fatally. It cannot be doubted that death was due to cancer, but the treat- ment gave wonderful benefit for a time in a desperate case. It looked at one time as if the disease might even be arrested for years, as in the case previously described. X " T 1,.,-k fur tv.,, ;,,.,! ;, ;a lf vears 1, -ra\ treatment. ( a-c alter !\vn yeai> t r< atn.i M hoconsulled the author about what she iirure S.'-U) i- (it a n; regarded as an un healed burn t'r< >m ./'-fay I rea H i icn t s bv another opera to] MKDlt \L F.l.Kl TRKITY AM) UO.NTi.KN HAYS s.-is.- - Inoperable carcinoma of breast held in chock for two and a half years bv Ront- genotherapy. Case a few weeks before death. f bn'.'isl \\il'i ftinnnou> edema of the 122' more than two years previously. These lesions are extremely painful and very slow to heal, though in the case referred to the carcinoma itself seemed to have been checked by the treatment. Jchthyol ointment and high-frequency currents applied from a glass vacuum electrode give more relief than anything else in such a case and also promote cicat rization. In addition to the carcinoma of the breast, this patient had developed a flat epithelioma of the other side of the face. The patient's daughter died of carcinoma of the breast. Prognosis. Cancer of the breast which has been operated upon and which has recurred gives excellent results at first, but after a certain period there may come a time when the disease pets beyond control. This may take a few months or several years, as in some of the author's Fin. S-t(). Inoperable recurrent carcinoma of breast. Held in check for a year by Ront- genotherapy. cases. The :r-ray appears to prevent the development of external growths or uleeration, and keeps the patient comfortable 1 and for a time strong and well. The (Mid, when it does come, is usually from internal involvement and often without definite symptoms. Scirrhous cancer of the breast in old persons presents a less unfavorable prognosis. RECURRENT CARCINOMA OF THE LARYNX The patient. AV. If., was a man of thirty-seven years, and was re- ferred to tin 1 author in April. 1 !<).">. by Dr. Moore, of Xew Brunswick, X. J. The first symptoms of throat trouble developed in April, 1902. On April 17, 1!()1. he had undergone a complete excision of the larynx for carcinoma, and during thai year had been breathing through the tracheotomy tube. In February, 1'ifi."). however, he became unable to swallow ail}' food, either liquid or solid, in consequence of the return MKDICAL KLKCTUK ITY AND RONTGEN RAYS of the growth shutting off the esophagus. A gastrostomy was per- formed March 15, 1!M).">, by ])r. Moore, and at about the same time the doctor wrote to me, making inquiry as to the probability of benefit from .r-ray treatment after recovery from the shock of the operation. The reply was encouraging, and a few weeks after the operation had been performed the patient began making regular trips to my office for .r-ray treatment. When 1 first saw him there was a considerable swelling in the neck, presenting almost the appearance of a new larynx, and above the tracheotomy opening, in the median line, was a discharging sinus, from which some of the liquids, milk. etc.. which he tried to swallow escaped. The whole region was red and swollen, and pre- sented the typic appearance of a recurrence of carcinoma. An .r-ray picture which is reproduced herewith (Fig. 841) was made, and shows the presence of the hyoid bone and the absence of all the cartilages of 1! C-.i-i- < > f l.-irvTiircctumv niul bom-fit from .r-r:tv trr-.'itnifiiT for rffiirrciil .:-::. L r '_' -trutomv. J.iirlit ;irc:i in mini > upper verteunr: pturnl part <>1 , i . uml t ; the larynx, and demonstrates also very prettily the obliteration of the trachea below the level of the hvoid bone. The patient's weight at t hi- imc wa~ 10H pounds. I he treatmeiil consi.-led in the application once a week of the r-ray. allowed to shine above the front and side- of the neck. All oi ' he-e a pplicat ions were < \ternal, and i'ollowei 1 a very d is! met formula Mi* author has found -ucces.-ful m manv cases of recurrent malig- o t uniors. The r-r.'tv lube ha- a tuntr-ten anticalhode and i- about 7 inches in diameter, and has also an accessory anode. A little side tube, con- ned . '_> wii ii t he main one, has means !or li iweriim" the degree o| \-aciium li\- -en . u'j ',] portion < >f ihe current through thi- regulator. The anti- c:i ' : - a m. -i ' if cop pi r. \\'ei^hin^ \ pound, with a but Ion of t ungsten -urfacc which faces obliquely toward the K(")\T( ; K\( )TH KHA I' V 1 229 cathode. Tungsten has a melting-point twice as high as that of plati- num. With a moderate strength of current this type of tube maintains its degree of vacuum longer than most other types. The metal does not liberate many particles of gas unless it becomes red hot. At the dif- ferent treatments the spark length varied from 2\ up to o inches, and for one or two treatments even 7 inches, while the degree of pene- tration varied from 2 to (> or even 8 units of the Benoist radiometer scale. The effect of treatment was to reestablish the ability to swallow, though this always remained difficult, to materially increase the man's weight and strength, and to cause a great reduction in the cancerous swelling in the neck. This improvement continued for about a year, but did not save the man's life. CANCER OF THE TONGUE Guilleminot 1 reports 4 cases of carcinoma of the tongue unsuccess- fully treated by the .r-ray. CANCER OF THE SHOULDER A case of inoperable cancer of the shoulder has been reported as cured by .r-ray applications. 1 ' SECONDARY CARCINOMA OF THE MEDIASTINUM Carcinomata of the mediastinum, secondary to cancer of the breast, have been treated with benefit in the direction of relieving symptoms and prolonging life. Pfahler has published the histories of such cases. The object should be to us* 1 such a quality of ray and to have the tube at such a distance as will produce a deep effect without undue irritation of the skin. The ant icathode of the .r-ray tube should be about 10 inches from the surface* and the penetration should be about No. 7 Benoist, (i-inch resistance, 70 kv., '*> ma., but the proportion of soft rays reduced by the use* of a o mm. aluminum filter. A maximum exposure would be ten minutes, equal to "> II.. and not to be repeated be greater from frequently repeated mild exposures than from single severe ones. A dosage of \ Ilol/knecht unit will usually be found cor- rect. The cross-fiiv system, whereby the ray- reaching the growth pass through different portion- of skin each time, and e.-pecially always protecting the skin, which i- not in a direct path toward the growth, add greatly to the efficacy of the treatment. CARCINOMA OF STOMACH AND INTESTINES \\ e can seldom hope tor more than a palliative effect in cancer of the stomach or intestines, but even here tin 1 treatment give- much relief from pain and adds much to the patient's strength. A case treated by the author, in consultation with l)r. T. M. Lloyd. Allowed temporary relief front pain and from almost complete pylorir obstruction. He became able to retain food and had natural move- 12 MO MKim'Al. HI.KCTHICITV AND lit >NTi ; F.N KAYS iiH'i!!- ot the bowels, lie died. however, in a few weeks from exhaus- tion. The disease \vas of long -landing and of such an extent and the patient's condition so critical that no operation appeared justifiable, and the .r-ray and the ultraviolet ray high-frequency applications were made with tin' hope of temporary relief only. More recently the author ha- Treated such cases at a somewhat earlier -taue and with very great benefit. A screen of aluminum o mm. thick ha- been u-ed and the anticathode placed at a distance of 10 inches from the skin. A palpable tumor of tin 1 right iliac region in a patient referred by Dr. Park', proved to be a gelatinous mass which recurred after opera- tion. Tin- recurrence was also accompanied by distention of the abdomen with the saint 1 gelatinous substance. .c-Hay applications to all four quadrants of the abdomen combined with radium applications to the ri^ht iliac tumor made a very great improvement in the patient's weight and strength, ability to take nourishment, and in the action of the bowel-. Combined with occasional operative removal of the gelatinous substance, the treatment has maintained this improvement for some years. The diagnosis is obscure. CARCINOMA OF THE UTERUS A patient was rcfcrn-d by ])r. Hoyle. She was a lady fifty years old, with a very large uterine fibroid winch made her look as if in the last month of pregnancy. Carcinoma of the cervix had developed and she ndergone a:i operation under ether. 'The whole pelvis was found to be one solid ma-.- of cancer, and so the operation \va.- limited to the removal of a section large enough to examine microscopically. The pathologist reported carcinoma, and the probability seemed to be that it could live bul a few weeks. Treatment b\ the .''-ray was begun, however, the patient having to come in a carriage, assisted by her physician and her mother, husband, and nurse. There was an : nd very offensive discharge and great pain over the ovarian and lumbar regions. The .r-rav was applied partlv over the abdomen II I >ugli a vaginal speculum. T'ne distance tVom the anti- f-athodf to the abdominal wall was 1.'! inches and the rays were \<>. 7 mlit minutes. ( Mherwise the details were the same i- in the case of cancer of the brea-1 described on p. l_'_'l. The same t !(': nar \\as ii- tlie vaginal applicat ion-, 'i'he .r-ray tube was a No. \'-\. and lo'-ah/al i. :n wa- accomplished bv covering i in- pat lent '.- bti: tock- and t hi^rh- wit h .r-ra.y me; a i wit h :\ hoh- ju-t large 1 i j y\'( 'si 'lit \\ i'! i ing t he atii !n *r makes -imila r ca.-e- b\ then-eol a locali/ing shield and : w i 1 1 1 ! t . \ : rom one pi ' of the /'-ray coil were applied over 1 - ; i eal ment . The t real - : ' . month.- i ' ; i , ' ' ' 1 1 ' : . ' . . . : ' ' : \ ;':! RONTGENOTHERAPY 1231 ably from cancer, but without any of the pathognomonic symptoms of that disease. Other cases t reated by the author and other operators show that it is not unusual to have marked improvement as to hemorrhage, discharge, pain, odor, and general strength. It is practicable even to carry such a patient through pregnancy and to see a healthy child horn, but the ultimate prognosis seems to he uniformly bad. General Results in Carcinoma. The preceding cases of carci- noma, some cured, but most treated with very great temporary benefit, but nevertheless dying in from six months to six years, are fair exam- ples of what may be expected from /-ray treatment of this disease. SARCOMA The author's teehnic is 0-inch resistance. 3 ma.. 10-inch distance, 3 mm. aluminum filter, ten minutes for a "massive"' dose over each area, not to be repeated inside of three weeks. Squamous-celled epithelioma is less favorable for radiotherapy. The best are tumors with the largest and most prominent nuclei. Lymphosarcoma recurrences end in death. 1 /-Hay or radium should not be tised before operation and should not be neglected after operation. 2 Many cases of this disease are favorably influenced by /-ray ap- plications and a few cases have perhaps been permanently cured. There is no particular form of the disease which is recognised by all observers as especially apt to be favorably influenced, and in no form is this treatment cont raindicnted. The general principle is the same as in the "radiotherapy of other malignant disease- the .r-ray has a depressant effect upon ever\* kind of tissue. The rapidly proliferating cells of neoplasms, like the normal cells of the testis and the ovary, are more susceptible to ihe influence of the .r-rav than other ceils. The /-ray is applied in doses from which the more susceptible tissue-cells cannot recover, but from which the neighboring sound tissue-cells do recover after a period of depression. V\ here small repeated doses are employed ihe quantity applied is such that the- sound cells completely recover from the effect of one application before the next one is made, while the neoplastic cells, more decidedly affected, do not completely recover between applications and experience a cumulative eitect. Ihe operator arranges the strength and frequency of the applications with t his end in view. Ilolzknecht regards sarcoma as more easily influenced than epitheli- oma hv the .r-rav. Colev, who is not a, radiologist . but who has had a large number of cases treated In* the /-ray. helieve< thai the mixed toxins o| ervsipelas and M reptocnccns an o! urea! value in sarcoma. According to his conclusions, ihe antitoxic ; realm -n!, either alone or Mos :t. ; : < :!o'ji-: =, on t he oi hi r hand. , ' : ; hue or i "i- IM ci ion \\ f' i! -ui'irical nn asup - :- : : ; : :' .- '. momen' after ihe diam MH1MCAL KLl-XTHUTTY AND KOXTCEN RAYS be removed with a reasonable degree of completeness without danger to life and without too great mutilation. The .r-ray has been employed as a prophylactic before surgical treat- ment. The advantage to be derived is somewhat doubtful as com- pared with the benefit to be derived from an early operation. Still, if the case is not a threatening one, and if the patient's general condition is such that preliminary constitutional treatment by tonics and hygienic surroundings is required, .r-ray treatment may be recommended during this preparatorv treatment. The benefit sought is to reduce the size of the tumor and so make it susceptible of more complete removal, and especially to convert some of the lymphatic channels into fibrous cords ami thus reduce the liability to the formation of metastases. These preliminary applications should include a generous area of tissue around the growth, and the doses had better be mild and frequently repeated. Prophylactic applications after an operation are of undoubted value, and may be begun immediately after recovery from the effect of the operation. It is not necessary to wait for the wound to heal and the applications may be made through the dressings. The doses should be small and frequently repeated, and should be continued until about 7 H. have been applied in about three; weeks. Then applications of 1} or 4 II. may be mad* 1 every two weeks for two or three months. 'Flu 1 qual- ity of the ray, as represented by its degree of penetration, depends upon the depth at which the lesion is lo- cated. No. "> to 7 Benoist, .l-inch resistance, is correct for the treat- ment of the cicatrix after an am- putation of the breast, while rays No. or 10, (i-inch resistance, would be suitable for a case of sarcoma of the kidney. The use of a screen for soft rays is to be recommended in almost every case. The rays which I hose which would be absorbed by the skin, and by we are enabled to make more effective applications TREATMENT OF AN INOPERABLE PRIMARY OR RECURRENT SARCOMA \\liat i- said under I he head of Melanosarcoma and in the earlier paragraphs on Sarcoma give< the author's view> as to prognosis. The treatment i- a little different, however, in the direction of being more -i vere. It should be as thorough as possible without causing ulcer- alion. Kit her the method ol large doses of about 7 II., repealed everv I \\'o or three weeks, or that of smaller doses. 1 or 2 II., everv two or three days, may be applied. The same differences between deep and -iiperficinl lesions call for differences in the degree of penetration and also IMF dillerences in the distance from the anticathode to the surface of the [tody. The latter distance may be as small as desired when the disea-e i- practically on the surface of the body, but the distance from the ant icat hode to t he -iirface of t he bodv must be about II) inches when K<">XT< ; K.\< >TI i KKA i' v 1 233 the disease is deeply located. This is on account of the fact that the intensity of the radiance diminishes as the square of the distance in- creases. The distance from the anticathode to the skin should, there- fore, he a large fraction of the distance from the anticathode to the dis- ease, so as to make less relative difference between the two distances and less difference between the intensity at the two places. \Yith the tube close to the surface the intensity at the skin may be four or six times as great there as at a deep-seated growth, and hence it would be impossible to produce sufficient effect upon a deep-seated growth with- out destroying the skin. This is without taking into account the fact that the deeper tissues receive a reduced strength of application in con- sequence of absorption by the superficial tissues. A localizer. such as the Ripperger shield, with a 4-inch diaphragm should be generally used to limit the action of the rays to the region of the disease. rlopatt 1 reports the case of a woman, with probably malignant lyinphosareoma of the anterior mediastinum, successfully treated bv lifty applications of the .r-ray. Radiographs showed a reduction and finally the complete disappearance of the unnatural shadow cast by the growth, and there was a coincident disappearance of tin- dyspnea and other symptoms. It is not known whether the growth recurred. Helot and Bissene-' have treated cases of diffuse sarcoma of the skin and of premycosis and mycosis fungoides by the .r-ray. The last- named disease, although due to a germ infection, has many of the prop- erties of cutaneous sarcoma, and the .r-ray in massive doses of o to 7 Holzknecht units of rays No. I or "> Benoist has effected a cure in the two or three cases in which it has been used. Scholt/ uses even larger doses, intending to produce superficial necrosis, but this does not seem necessary. In the cases treated by Belot it happened that one or two small regions accidentally received a larger dose than 7 H., and the effect was less desirable than elsewhere. A case of very malignant sarcoma, involving the soft tissues at the angle of the jaw. recurring after t wo opera t ions, disappeared under .r-ray treatment and had not returned a year later. 3 Xo doubt exists in the author's mind of the occasional permanent curability of sarcoma, both of the bones and soft parts, by Rontgen ray treatment. This is also the experience of Skinner of New Haven., Piah- ler of Philadelphia, and M. L. Dorn among others abroad. MELANOSARCOMA This disease usually responds favorably to .r-ray treatment, and shows either an arrest of the morbid process or an almost complete disappearance of the visible lesions. Some cases which have been re- pi >rt e< 1 showe< 1 onl v a very t empoi a rv arrest . but in most case.- tin' benefit was long continued. The ultimate result, it i- to be feared, will be that the majontv of eases cannot 'he permanently held in check. .Mild. frequently repeated doses, without ever exciting an inflammatory reaction, have given good results m some cases, while a case treated bv Bisserie, an ulcerated inelanosarcoma of the nipple with axillary adenopathy, received an application of !) 11. ot ray.- Xo. -t or .">. re- peated fifteen days later. There was an intense reaction, followed by 12:} l MKDH'AL ELECTRICITY AND KOXTCEX KAYrS complete healing ;>f the ulcer, and three months later there remained only a small non-ulcerated and painless tumor of the consistence of a lipoma. The milder method is generally more suitable for non-ulcerated sar- I'iir. ^43. Molanosarcoma of back, recurrent. Only one or two rr-ray treatments; with- out much effect. comata and the severe applications for the uleerated and more threat- ening cases. As in other cases of malignant disease, the application should gen- erally l>e limited to the region immediately embracing the dis- ease. Some constitutional effect is doubtless always produced by breaking down of malignant tis- sue under the influence of the .r-ray. and the author believes that in many cases an antitoxic action is thus secured. Kxten- sions ot disease in regions not exposed to the .r-ray or in conse- quence of their deep location re- ceiving only a small fract ion of the dose applied to surface lesions of ton receive marked benefit . which 1 he author Accounts tor on the hy- pothesis given above. ( 'ases may occur in which the same profound effect on the Mood from which so much benefit occurs in leukemia mav be sought in sarcoma. It may 1 ie o! it ained ! iy applicat ions over 1 he spleen and I he long bones. The c;iT!I K.UA I'Y 1 235 those did not produce any perceptible e-hange in the course of the dis- ease. The case is introduced niorolv for the purpose of describing the author's technic. The .r-ray tube was a. Mi'iller No. 13 heavy anti- eatlKtde 1 tube (> inches in diameter. It was enclosed in a Hippor^or shield or wooden box lined with lead oxid. At a distance of (>.', inches from the antic'lthode there was an opening (i inches in diameter, which was (lin % cted toward the part to be treated. The patient lay face down on the table, with the anticat hode of the tube 13 inches from 1 he surface of the back; an area S inches in diameter was, therefore, exposed to the .r-ray. A 12-inch induction-coil was used with the 110-voll direct cur- rent and a Wehnelt interrupter, transmitting fi amperes of primary cur- rent and sending 1 ma. of secondary current through the .r-ray tube. The rays were No. Benoist, 4-inch resistance. Kach exposure lasted three minutes, and was equivalent to 1 Ilol/knecht unit. These ap- plications were to have been made three times a week until a slight cutaneous reaction was established, and then reduced in strength or frequency so as to maintain a slight reaction. A case of recurrent alveolar melanotic sarcoma, of the neck seemed to be entirely cured by three 1 months' .r-ray treatment a.pplied after the second operation. The wound had failed to heal and the growth was rapidly extending to the entire neck. 1 MULTIPLE PIGMENTED SARCOMA The .r-ray affords some benefit in this fatal disease and is the only treatment that does so. The difference between this and melanosarcoma is in the arrangement of the cells and also in the fact that the pigment in melanosarcoma is largely melanin, and in this disease 1 it is mostly hemosiderin. It usually first develops on the hands or fee't and extends upward to involve vital organs. 2 Stcoutliirji x-Itai/s from Silver hi the Alimentary CaftaZ. Hernaman and Johnson 3 have found that there is a elefinite value to the 1 secondary x-radiation fre>m metallic silver in the alimentary canal for the' treatment of malignant disease thereof. FLUORESCENT MEDICINES IN CONNECTION WITH X-RAY THERAPY Experiments by the author show that the various fluorescent media which have been given internally while* the patient was exposed to the .r-ray probably have 1 no beneficial result, due to the luminosity e-xcited. Some of them, like bisulphate of ejuinin. are excellent tonics in themselves, and this is not questioned at all, but the .-pecial claim ha> been made that these substances, circulating in the blood and in all t lie other tissues of the body, become fluore'scent under the influence of the .r-ray and generate light in the tissues and that this light has a beneficial effect upon cancerous tissues. The tact that so good a man as \Ym. J. Morton advocates this method is sufficient to make it worthy of the mi isl careful considerat ion. The fhioresconl medium recommended by Kemp for gastrodia- phany is: Ouinin bisulphate 1 , gr. x. in a glass of water, to which i.- aelded 111 iv of dilute 1 phosphoric acid. After this has be-en .-wallowed a glass of plain water is also to be taken. 1 Dr. Kihvin Walker. Medical Hmml. Xov. S, 1 <>()_>. - LirbiTthal. N<-\v York Mccl, Jour.. June ~2:\. I'.iiMi. 3 Abstract, Aincr. Quarterly ut" Hui'iit^i'imlnu-y, M :i ivh. Hirj. p. ."7. MKDK AI. KLKCTUIC1TV AM) KnNTOKN KAYS I his uives sufficient fluorescence when an electric lamp is intro- duced into the stomach to produce :i visible luminous area indicating the sixe. shape, and position of the stomach. The experiment must be curried out in a dark room. Fluorescin is more strongly fluorescent and is non-toxic in the strength of i to } grain to the pint (gin. 0.07 or 0.14 per ">()() cc.j. Fluorescin produce.- a medium for gast rodiaphany when prepaied as follows: (live the patient S ox. of water with ,~j of glycerin, gr. xv sodium bicarbonate, and gr. J fluor<-scin. This should be prepared one-half hour previously and exposed to sunlight. F.-culin is also an excellent non-toxic fluorescent substance. Fit her of the. three media described above will become luminous when ordinary light shines through them. This is due to a slowing of the rate of vibration in the waves of light in passing through the liquid, and each particle of liquid becomes in a certain sense a source ot colored liuht nearer the red end of the spectrum than the light was originally. White light, seen by transmission through such a .-oh it ion, may have one color, while by reflection it sometimes lias quite a different color. Many fluorescent substances are dichroic in this way. A striking example of the slowing effect upon vibrations of light by fluorescent substance's is shown by a simple experiment: The spectrum of the Cooper-Hewitt mercury vapor lamp is almost a pure violet', as seen in a spectroscope, but when a piece ot cloth coated with a suitable fluorescent substance is held close to the lamp and the reflected light from t he clot h is examined, t wo brilliant red lines are seen to spring into view. Fluorescent substances become luminous and variously colored under the influence of the ultraviolet rav, which is itself of such rapid vi brat ion as to be invisible. Thev also behave in t he same way under the influence of radium ray.-, themselves invisible. Thev inve the same phenomena under the influence of the ./"-ray as in the case of the barium plat inocyanid screen, which is so universally u-ed in fluoroscopic examination.-. NATURE OF THE RADIANCE FROM FLUORESCENT SUBSTANCES '1 he aut hor's belief that I he radiance t rom t hese .-ill ist a nee- consist s practicallv entiivlv of ordmarv visible li^ht. and not of invisible ultra- violet rav-. i- ba-ed partlv upon the following: Kj-jii-riniftil (by the author, Feb. L'V !!)()?*).- .\ Machlett .r-ray tube, nivinu' rays No. 7 IVnoi-l. .~>-inch re-i-tanee or -park equivalent and ."> Ilia., u a- r -ii closed in a Ripperger -hield. wit h a 1-inch diaphraum in a per- fed 1 v dark room . A piece ol \\ illemite, exposed direct Iv to the radiance from the .r-ra \' ! ul >e. showed the -a me ^ reen fluorescence that expo -in e to !' lolet ray lamp produce- m it. It \\a- much le-- brilliant, how- e\'er, ' '.', ou Id have been m the latter ca>e. Still. \\ illemit e wever, when the \\ illemit e was licit 1 somewhat to one side of the open- ing in the diaphragm so as to be shielded from the , /'-rays, though near enouglit to the brilliantly fluorescent barmm plutinocyanid screen to recei\ r e whatever rays emanated from the latter. The result was a pale, from an ultraviolet lamp has to pass through ordinary glass to reach it, and is in this way deprived of the ultraviolet rav. Interposing a piece of ordinary glass between the fluorescent screen and the Willemite did not lessen or change this appearance in any way. The last part of the experiment seems to show that the radiance emitted by barium platinocyanid under the influence of the .r-ray does not contain the .r-ray or any of the rays characteristic of radio- active bodies, or the ultraviolet ray in sufficient amount to be demon- strable by so delicate 1 a test as Willemite. A strong solution of fluorescin (gr. j to oz. j ) in a perfectly dark room fluoresces brilliantly when exposed to the .r-ray from a tube entirely enclosed in black paper (experiment by the author Feb. 29. 1904), so that no visible Hu'ht could ivach the solution. The proper solution for internal administration (experiment by the author March 4, 1904) consists of (1) gr. -J, fluorescin in ~>j alcohol, (-) f>ss glycerini. (.'>) f>ss to j olive, oil. (4) water, q. s. ad. 1 pint. Mix thoroughly at every stage. The above solut ion gives only a questionable fluorescence with the unshaded .r-ray. The same solution fluoresces well with the light from an ultraviolet ray vacuum electrode. This solution really forms a very delicate test for ultraviolet rays. Since it shows onlv a doubtful fluorescence when exposed to the .r-rav. it is evident that no appreciable generation of ultraviolet rays can take place 111 l! when so exposei 1. Kven if the stomach were filled with this solution in a case of cancer oi t hat organ, exposure to the .r-ray could produce only trivial luminositv in the liquid and probably no ultraviolet rays. When we consider the hundred or more applications of an hour each from an ultraviolet lamp of KIIK) or more candle-power required in the treatment of lupus or epilhelioma. it seems impossible that the feeble radiance from the liquid in question, acting for only a few minutes, could produce any effect upon the cancer. I 'he author has given a fluorescent solution of quin in m tin- way m a case oi cancer of the stomach and could not see that it modified the effect of the .r-ray in any way. Another experiment by the author (March 12. 190 H consisted in partly removing the vegetable matter which filled the stomach of a dead rab- bil and replacing it with a radio-active solution and then making a radiograph showing the stomach region. The .r-rav l ube was enveloped m ! >l;ick paper and i he room was darkened. No fluorescence or gastro- diaphanous appearance was visible. The fluoroscope showed great franslucency through the dilated stomach, and tins same tact is shown in the radiograph. Another radiograph, inade after the stomach has fern emptied, shows a verv u'reat difference. ( >nlv a skilled anaionn-t could tell where the stomach i.-. The conclusion from t his experiment is that a radio-active solution introduced into the stomach doe- not assist m radioscopy bv any transillumination effect. Since the increased i u'liet rabilit v was attributed to the mass of vegetable matter m the MEDICAL ELECTRICITY AND KONTGEN KAYS stomach it is not probable that the radio-activity of the solution had anything to do with making the radiograph >how the stomach more clearly. INFLUENCE OF THE INJECTION OF PHOTODYNAMIC SUBSTANCES INTO THE TISSUES BEFORE A'-RAY EXPOSURES A solution of eosi n 1 : 1000 has been injected into the tissues by Kothe, 1 who has found that verruca 1 will disappear after an exposure to the .r-ray too short to produce any effect upon other verruga 1 which had not been injected. Similar results were obtained in treating lupus and in experi- ments upon rabbits. RADIOTHERAPY IN INFECTIOUS DISEASES SPECIFIC IMMUNITY The development of toxemia under .r-ray applications hailed to the suggestion by A. AY. Crane 2 that .r-ray applications might be used to generate 1 an antitoxin in the system of a patient suffering from an infec- tious disease. This has not been sufficiently experimented with to know whether it will prove efficient. Possible advantages are that the anti- toxin (using the term in a broad rather than a strictly accurate sense) liberated is derived from the identical germs or morbid tissues which are present in the patient, and thus the harm which might come from an error in diagnosis and the use of the wrong specific antitoxin or serum by ordinary inoculation is avoided. The method does not at all sup- pose a direct bactericide action of the .r-ray upon pathogenic micro- organisms in living patients. RONTGEN APPLICATIONS FOR PRODUCING STERILITY Men may be rendered sterile without loss of desire or ability for coition. The reported cases in which this has been done were given applications sufficient to produce decided dermatitis without ulceration of the scrotum. The spermatozoa were still absent six months later. Women may be purposely made sterile by exposure to the .r-ray applied over the ovaries. The greater thickness of tissue to be pene- trated makes this require more total exposure than is the case in men. A-'vnvlli Aitilio'' reports the cure of a case of osteomalacia by in- ducint: ovarian atrophy through .r-ray applications. (iatiss 1 regards the attempt to produce sterility by the x-ray as dangerous, and when he attempts to produce abortion obtains a written promi-e from the patient to have an operative abortion performed if the .r-ray fails. This is to prevent a possible lawsuit for the birth of a lefi >rmed child. I). iiN<-h. M-'l. Worh.. Sept. 1",. I'.uil. '- Am. .Jnur. <>f .Mi'.lir;tl Sciences, M:uvli. !'.()*. 1' illctiriD 1 l.y A. II;t!iiin. Tlic-r.-tj). Monutshcfte, xxvii. No. 7, July, 1913. RADIUM KAPIUM is a new clement, which is supposed to exist, but which has not yet been isolated. Several of its salts, especially the bromid and the sulphate, have been obtained in what is thought to be a pure slate, and if is from the study of these that our knowledge of radium itself is derived. It is classified as a metal of the alkaline earths, very similar to barium. Its atomic weight has been calculated to lie about 226 times that of hydrogen. It is thus one of the heaviest metals. The other metals which are radio-active also have very high atomic weight. The atomic weight of polonium is 234; that of uranium is 240; while that of bismuth, which is radio-active from an admixture of polonium, is 208. This very high atomic weight is thought to account in some way for the property of radio-activity possessed by these substances. The spectrum of radium shows twelve distinctive lines, one of them in the ultraviolet region being particularly marked. Pure radium bromid colors the flame of a Bunscn burner carmine. Such small amounts of radium salts have been produced and they are so expensive that the efforts of the chemist have been devoted to the means of obtaining them in a pure state rather than to a study of the various possible compounds and reactions of radium. The bromid is the most active; salt of radium, and occurs in the form of small white crystals, which are very soluble in water. It is hygro- scopic, and exposed to the air will gradually absorb sufficient moisture to become liquefied. Kadium chlorid has the same properties, but is not so powerfully radio-active. The sulphate and the carbonate are white powders and are insoluble in water. The sulphate is preferable for almost every purpose 1 except for the intravenous or subcutaneous injection of a radium solution. Xone of these 1 radium salts are destroyed or dissipated even by a red heat, although their radio-activity is some'times temporarily reduced. Kadium, therefore, is less interesting from a chemic than from a phys- ical standpoint. The complex phenomena known as radio-activity are what make 1 radium inteTesting and valuable. RADIO-ACTIVITY Kadio-active substances were discovere-d in IMMt. shortly after Kfmtgen's discovery of the .r-ray in ls!)">. Becquerel found that rays of a character somewhat similar to that of the .r-ray were given off by the 1 metal uranium. Becquerel rays (named from their discoverer), <>r the rays froir, uranium, produce- many of tin 1 effects of the .r-ray. They affect a photographic plate, ionize gases, and this electrification is governed by the same laws as in the case of the .r-ray. The Becquerel rays, how-, ever, are 1 reflected, refrae'ted, and polarize 1 *! in the same manner as light, 1239 1210 MKDICAL KLKCTKICITY AND K<">XT(,KX KAYS aiil mu.-T have about the same wave length. Class lias the same index oi retraction lor these ra\'s as for ordinary lisiht. The 3"-Rays or Blondlot Rays. They are given the name .Y-rays in honor ot Xancv, France, where Blondlot is a professor. The >ources troin which they are generated are the ordinarv luminous bodies, in- cluding the Crookes tulie. the \Yelsbach and -imilar lights, the Xernst lamp, red-hot metals, and the sun; and also non-luminous bodies, in- cluding bodies in a state of stress, sonorous bodies, a magnetic field, Hertzian waves, liquefied liases, odorous substances, soluble ferments vegetable tissues, and the human body. Thev ha\'e very similar properties to t hose of ordinary light , and under favorable circumstances are believed to make the human body visibly luminous in an entirelv dark room. It is only fair to add that many unprejudiced observers have found themselves unable to perceive this luminosity. Discovery of Radium. M. and Mme. Curie, of Paris, made a series ot very delicate tests of the radio-activity of different specimens of ura- nium residue, and fotind that they differed very markedly in activity. The inference was drawn that some substance of greater radio-activity than that of uranium was present as an impurity. This substance, which, however, has not been completely isolated, is called polonium, from Poland. Madame Curie's native country. The further investigation of radio-activity was carried on by the Curies, the line of investigation consisting in separating a mass of radio- active substance into two portions by chemic :M'oces.-es and testing the activity of each portion. The portion more highly radio-active is >ubjected to further chemic analysis, until finally a very small residue of very hiiihly radio-active substance is obtained. It was in thi- way that the discovery of radium was made. In its pure-t salts, the bromid. chlorid. and sulphate, its radio-activity is from l.SOO.OOO to '2. 000. 000 times that of uranium. Metallic radium ha- been obtained by Mine. ' 'urie and M. Dubierne through the distillation of an amalgam of mercury and radium pre- vioii-ly obtained by electrolysis. It.- atomic weight is a fraction less than >(i. Properties of Radio-active Substances. Thevgiveout a radiation and -omc of them '.rive an emanation, which both have peculiar proper- ties. Taking radium a- the radio-active substance ot urealest import- ance, j; i- found that it generates heat iii it. -elf without any apparent combmat ion, and t he.-e are i he onl v subM an ces which are known '> produce heai in this wa v without the applical ion of any outside force. A -pee imen of radium, whet her perfectly protected from the atmosphere ', i', con.-tantlv maintains a temperature i' or i! ( '. higher than r oi it - -urroundimis. Thi- heat . of course, radial es trom t he ra< hum ectiotis, as 11 would from anv oihei 1 substance will a tem- '']: higher than its surroundings. Its evolution is continuous and pi mifonii, and i- not accompanied by any perceptible lo-s of ' 'alciilation- have shown that the en t ire radial ion of lieal from a me that WOill' ! occur from a s pi i ere ot the -a me -i/e con- l . of radium per cubic meter i I .") 'jr. per cubic yard). ' heat, however, i- not 'he mo.-t important part of the prop' km iwn as ra> lio-act i\"H v. ii:: '<>} ' maintain- a negative elect ; - ic state, and radio- . the rnl\ one- v.-hi'-h do become spontaneou.-ly RADIUM 1241 charged with electricity. It has the property of charging substances with negative electricity, both those which are in contact with it and those 1 at a distance 1 . It also has the property of ionizing air or other gases and liquids. The current of electricity generated by a surface of 2', square centi- meters of barium chlorid containing a great eleal of radium and of a thickness of .2 centimeter is about T>O,OOO,OOU,OOO U111 P ( ' 1V - This repre- sents an amount of electric ene-rgy eejual to about 1(MH)U()0 | ) ^ att. Radium could never serve any practical purpose as a source of heat or electricity, the quantities of both being so very small in comparison with its cost. The Radiation from Radium. This consists of three distinct kinds of ravs the alpha, beta, and gamma rays which have entirely different properties. The diagram shows the 1 way in which these 1 differ- ent rays are 1 ai'fecteel by the action of a magnet. The olplia /Y///.S- are deviates! to only a slight degree 1 and away from the magnet. They are deflectiMl in the same elirection as the 1 Canal Si rahlen (Goldstein), or in the opposite* direction from that in which cathode 1 rays would be 1 deviated. The 1 !H In /Y///.S are deviated in the same' direction as that in which cathode rays would be deviated /. c., toward the' magnet and are- seen in the 1 illustration to be' brought around set as to impinge vertically upon the plane 1 from which they start. Some of them are more 1 deviablc than others and strike the plane nearer to the radium than others. The tfitnittirt /Y///X are not deviated at all under the magnetic in- fluence. The radium in the illustration is supposed to be at the bottom of a deep cylindric hole in a heavv block of lead. Practically .-peaking, all t lie rays would emerge as a slight ly divergent bundle of perfectly ,-t raight lines, but thev are subjected to a sort of analysis by the selective action of the magnet upon the different kinds of rays that go to make up the whole radiation. The radium gives out this radiation in straight lines in everv direct ion, but in the ill ust rat ion t he lead is supposed to be thick enough to absorb practically all the rays except those directed toward the- opening. None of the alpha, beta, or gamma rays are subject to refraction or reflect ion. They all produce electric, chemic, photographic, and physiologic 1242 MKDICAL KLK< TK1CITY AND KONTOKN HAYS effects, and all penetrate substances opaque to ordinary light. The different kind- of rays, however, have these properties to very different degrees. The alpha rays are believed to consist of particles of matter which, although almost incredibly small, are still quite large as compared with the particles that make up the beta rays. They travel at a speed of thousands of miles a second, but still at a slow rate as compared with the beta rays. They cany an electric charge as great as the negative charge carried by the beta rays. As a result of the great size of the alpha particles compared with their velocity and their electric charge the alpha rays are but slightly deviated by a magnet. They travel to a distance of only about o.."> cm. or l^,, inches through the air from the radium from which they radiate and they penetrate only the thinnest metallic screens. They are practically all absorbed by a sheet of aluminum -y-,/,, or -^fa mm. ( '7,\>G or j.,Vu inch) thick, or by * mm. of glass, the thickness of the wall of the smallest glass tubes in which powerful specimens of radium are sold. They have great similarity to the canal rays present behind the cathode 1 of an x-ray tube. Chadwick, working in Rutherford's labora- tory in the University of Manchester, has shown that alpha rays falling upon ordinary matter may produce gamma rays. Alpha rays constitute the greater part (04 per cent.) of the radiation from radium. The beta rays consist of particles of matter calculated to be about , V(> the size of a hydrogen atom, traveling at a velocity of 20,000 miles a second, carrying a charge of negative electricity, and being greatly deviated by a magnet in the same direction as the cathode rays in a ( 'rookes tube. Some of the beta rays are more (leviable than others in consequence of differences in their velocity. A piece of photographic paper laid along a line be! >w the word maf/nct in the illustration would be affected along a band starting from the lead receptacle and extend- ing outward for a considerable distance. The paths of the beta rays are bent by the action of a magnetic field of 2o()() units, so that practically none of t hem can reach a distance of more than 70 mm. from the radium. Th<-y are very penetrating, but suffer a certain amount of absorption in pas.-ing through solid substances or the air. and those 1 that get through are generally slowed. They produce a demonstrable effect at a distance of 2 or :> meters or yards if not deflected by a magnet or absorbed by some solid screen. They constitute about 24 per cent, of the radiation from radium. They are very similar to the cathode particles in an .r-ray tube whose impact gives rise to the Rontgen ray. < >nly a small part of the beta rays are of a highly penetrating char- ter and extend to a considerable distance through the air. They are ested by thick sheets of metal. The distance at which they are elective is influenced partly by the absorption they undergo in passing . _ : the air and partly by t he fact t hat 1 he intensity varies inversely i ; ; i.'irr of the distance from the point from which the radiation tak-- place. Absorption of Beta Rays by the Air. There are hard and soft beta ray-, and d! irradations between these. Their absorption by air is at lh' rate n imately 1 or 2 per cent . for each centimeter traversed. Measurement of the Velocity of Beta Rays.- Hecquorel's original method places tl e radium in a narrow, deep lead receptacle with a linear orifice. Above t! at some distance, is a diaphragm with a linear orifice KADI I'M 1243 at u right angle to the other. A magnetic field of a known strength causes (lifl'eivnt parts of the sheaf of l)eta rays to deviate; more or less as evi- denced by the action upon a photographic film placed beyond. The deviation indicates velocities of from 90,000 to 180,000 miles per second. The beta particles have various initial velocities, slower ones being the more absorbable. They all undergo a reduction in velocity in passing through matter. \V. Wilson 1 finds, for instance, that beta rays which start from radium with a velocity of 2.85X10 "' (/. e., 10,000,000,000) cm. per second are slowed to 2.55X10 '" cm. per second by passing through 1.5 mm. of aluminum. The alpha and beta rays are 1 those which are chiefly effective thera- peutically for surface work, and their properties, enumerated above, mala 1 it desirable that the radium should be directly in contact with the surface or only separated from it by the thinnest practicable covering. Origin of Beta and Gamma Rays. The atom of a radio-active sub- stance consists of rings of negative electrons surrounded by a positive charge, but in an unstable 1 condition, akin to a velocity of rotation such that centrifugal force exceeds cohesion. According to Rutherford, 2 there 1 are two types of instability the first leads to the expulsion of an alpha or positive particle 1 , the seconel to the- appearance of beta and gamma rays. A beta particle in escaping from the atom passes through the rings external to the one from which it springs, and at each ring it loses part of its energy in exciting erne or several gamma rays. The Gamma Rays. These are 1 not deflected by a magnet, but travel in straight divergent lines from the point from which they radiate. They are 1 highly penetrating and are 1 not entirely arrested by 2 or 3 cm. (about 1 inch) of lead or glass. They do not consist of material particle's, but are- of the same nature as the .r-ray, and are, therefore, supposed to be a form of motion. Their velocity is the same 1 as that of light. They are less active physiologically than the 1 other radium rays, it being a general truth in regard to radiations that the effect occurs only where they are absorbed. They form 10 per cent, of the radiation from radium. Some 1 gamma rays are more 1 penetrating than the most penetrating .r-rays from a Crookes tube. ()udin :! says that he lias seen a glass tube containing .75 gm. of pure radium bromid in Curie's possession bril- liantly illuminate a barium platinocyanid screen through a thick she i et of lead. There are all degress of penetration in these 1 gamma rays. Interesting Theories About Radium. Frederick Soddy' considers the 1 following as probably occurring in the evolution of the elements: rranium change's into radium, radium into emanation and successive 1 products, lead changes into silver, and these change's are 1 spontaneous. Radio-activity and the Internal Structures of the Earth. An exami- nation of a great many rocks and minerals shows a greater amount of radium than would be necessary to maintain the internal temperature of the earth if it contained that proportion all the way through. There 1 cannot, therefore, be the same percentage 1 of radium below a e-ertain elepth. This is apropos of Rutherford's observation that the 1 earth con- tains enough radium to account for its internal heat. Rutherford ex- amined many rocks and minerals iR. -I. Strutt). 1 Proc. Royal Sor., s4. 1910. p. 141. - Le Radium, 9. October, 1912. :7. 3 Ibid.. Sept.. 190(5. 4 Congress of the British Association, 19fXi. 1214 MKIHCAL ELECTRICITY AND RONTGEX RAYS The Radiation from Different Radio-active Substances. Ra- dium uives out alpha. beta. and gamma rays: polonium gives out only alpha rays: actinium give< out alpha, beta, and probably gamma rays; ura!iium gives out alpha and beta rays; thorium gives out alpha and The Ionizing Effect of Radiation from Radio-active Substances.- The air in which radium is placed is ionized and becomes a conductor of electricity. This effect may be shown in two dif- ferent ways: one. by charging an elec- troscope with stat ic electricity and not- ing the fall of the divergent gold leaves as the electroscope becomes discharged ; the other consists jn measuring the electric current from a battery which will pass across an ail 1 space introduced in the circuit (Fig. tat;c charge is carried by the ;,'/ from the electroscope to the metallic wall oi the cylinder and the '_n>Id leaf fall.- into contact with the vertical rod of the electroscope. The time 'hat thi- requires furnishes a certain measure ol the radio- 'i itv rif the substance. A telescope with a micrometer eyepiece - bi used to mea.-ure the exact rapidity at which the gold leal tails. A -creen i if any kind nuiv be introduced above the radio-active sub- ithi for the purpo.-e of testing the effect of various screens :-:.< i \- it \- ot' i he -a me Mibst ance. or as a mean.-- ol reducing vitv of a standard substance or of the substance to be Curie's Electrometric Apparatus for Measuring Radio-activ- 124.-) from it by a small air space. This upper plate is connected with the earth through an electrometer and a quart/ electric balance. The action of the battery results in the lower horizontal plate being raised to a potent ial of a certain number of volts. The air between the two plates being a non-conductor, no cur- rent passes to the upper plate, and consequently the elec- trometer connected with that shows no deviation. Now a radio-active substance is placet 1 upon the lower horizontal plate and the air between the two plates becomes a conductor ot electricity. A complete circuit is. therefore, established from OIK' pole of the bat tery tot he lower plate, through the air to the upper plate, and through the electrometer and the earth to the other pole of the battery. The strength of the current, as indicated by the electrometer, sinnvs the degree to which the air has been ionized and the radio- activity of the substance winch is being tested. For exceedingly weak currents the quart/ electric balance is used to exactly counterbalance the electromotive fo 1 ce of the battery and to prevent the passage of any current through the electrometer. Electromotive foice generated by the quart/ electric balance is susceptible of very delicate adjustment. It is sometimes desirable to first establish a direct connection be- tween the upper plate and the earth, which is broken after the electric current has begun to flow in a uniform manner. Standard specimens of different radio-activity are required for comparison, ami different screens may be Used, or the specimens of radium may be placed at a measured distance from the two plates instead of directly between them. The static electroscope is used chiefh radio-activity. The apparatus in Fiir. M7 Co.. is designed to detect a radio-activi I'-ed without a magnifying ula<- it shows Current Electroscope of Zeleny.' Thi- used for tc.^tinu: radio-activity to teartlett y of . ' n t hat of uranium, a radii Kid ivity of , ; . i- mi 1 he principle t if a static electric pendulum. One terminal i- charged to a potential of. say. 100 volts. A swinging sheet of u'old foil is attracted to it and. receiving a charire. is repelled, but as it is connected with an ioni/inir -pace it loses charge and is au'ain attracted. The number of excursions per minute f the sireiiiith of the ioni/iiiir substance, trument i< the one Used for testing th radium ramrinu; from 1000 to 1 .SOO.I it 124f> MKDICAL KLFJTKM 1TY AM) KOXTOKX KAYS The International Radium Standard. The one adopted was pre- sented to the International ( 'ommission by Madame Curie, and contains '2'2 mg. of pure radium bromid in a sealed "'lass lube almost completely filled. Measurement of the Radio-activity of Specimens of Radium as Compared with a Standard Specimen. .lust as all the linear measures in a country are based upon a comparison with a carefully prepared and permanently preserved national standard meter or yard measure. K. Rutherford 1 thinks an international standard of radio-activity should be preserved. The standard specimen should be weighed and kept in a sealed 'lass tube of known size and thickness of walls. The most reliable comparative measurement of radio-activities, which are very unequal, is by compensation. Two ionizing chambers are used, both connected with the electroscope in such a way that the current tends to pass through one and is opposed by the other ionizing chamber. Equal ionization in both chambers is indicated by an absence of current through the electroscope. In one chamber a plate of uranium oxid is used as a constant source of ionization. The first part of the measure- ment consists in measuring the distance 1 at which the standard speci- men of radium must be placed in order to exactly counterbalance the ionizing effect of the plate of uranium oxid. Then the same test \s made with the radium under examination. The activities of the two specimens of radium 'arc 1 directly proportional to the square of the dis- tance at which they will produce the same effect. This measurement is based almost entirely upon the effect of gamma rays, and caution must be employed to detect the presence of mesothor- ium which might produce an equal strength of this radiation at a cheaper cost. This may be detected by dissolving the supposed radium salt in water and boiling for several hours to drive off all emanation. Exam- ined immediately afterward, the radiation from radium will be free from gamma rays, while 1 hat from mesothorium will contain them abundant ly. A substance of very low radio-activity, like mineral waters, is tested by a comparison of its emanation with that from a standard solution containing, say, 10 '" grammes of radium to the cubic centimeter. This solution is perfectly stable, especially if a small amount of hydrochloric acid is added. Radium Testing by Photographic Effect. The author finds this ex- cellent for practical therapeutic work. The Tousey Unit of Power.- This is the photographic effect upon kodak film by 1 candle-power incande-cenl electric light with a carl ion filament, and with the usual blight ness or whiteness. One Tousey meter -erond i- the effect produced by such a light at a distance of 1 from kodak film in one -erond. For actual measurement a port ion c him mav be previously exposed to 1 Tousev meter second of m- caiii ' ceni elect ric lio hi . and ol her port ions are exposed to the specimen employing the condition- under which it is to be used. For of the author'- radium instruments i- a small glass tube, approximately 'JO milligrams of radium with an approxi- nf '_>. (Kill. OIK). This i- placed close to the kodak film, Mr-fare up. but the film covered bv two thicknesses of black portions are exposed to the radium for various num- ' 'i> :'! r;ia--rd t hrouii'h the hole in the amber spool and i- withdrawn when the _: !> i leaf i- -ecu tn di vi rue. \\ iiid< >ws at oppo>H e side^ ol the ionixiition lier allow of observation through the microscope indicated by the dotted circle //'. Screeii> (it dillereiil materials mid thickness mny be inl I'oduced t hroiiiili the -lit A'. The -teli i / of t he elect 1'oscope is a brass rod 1 mm. i hick and '.\ cm. loiiu 1 . t he u'old leaf ha \ iuu t he .-a me dimensions. ORIGIN AND COST OF RADIUM in -inall i iiia ni it ie.- in inaii\' diflerent iniiieral- found KADIUM 1249 springs. For practical purposes it is extracted from pitchblende, a heavy black mineral, looking somewhat like anthracite coal, but break- ing with a smooth fracture without jagged corners or edges. < )ne of the principal deposits of pitchblende is at Joachimst hal in Bohemia. This mineral contains uranium oxid, which is extracted from it. The residue at a certain stage of this process contains the radium of the original mineral in quite a concentrated form, but still closely associated with a do/en or more other elements. The treatment of a ton of this residue requires 5 tons of various chemicals and 50 tons of water. The product is about 1 gram (15 gr.j of pure radium bromid, with a radio-activity of 2, 000, 000. From 500 tons of the ore (carnotite. etc.) 1 gram of radium is obtain- able 1 , a concentration of 100, 000. 000 is therefore required. The price at which this was sold in 1909 was $80,000, or 400,000 francs, or L'15,500, and the price has increased 50 per cent, in 1014. Smaller quantities are sold at a corresponding fraction of the price per gram. The best manufacturers prepare the less powerful specimens of radium bromid by taking a certain percentage of pure radium bromid and adding the necessary amount of barium bromid. The price is a corresponding percentage of that of the same quantity of pure radium bromid. One decigram (I 1 , gr.) of pure radium bromid with an activity of 2,000.000 costs $12,000 in 1914. O-ne decigram of radium bromid of ISO. 000 activity (containing, therefore, 10 per cent, of pure radium bromid) costs 81200. One decigram of radium bromid of 20,000 activity costs 8120. ( )ne gram (15 gr.) of radium bromid of a radio-activity of only 50 (Y. c., fifty limes that .of uranium) costs 8l>. The other radium compounds. c. ;/., the sulphate and the chlorid are prepared in various strengths and sold at prices corresponding with the radio-activity of each specimen. VARIATIONS IN THE RADIO-ACTIVITY OF RADIUM The purest radium salt does not present any marked radio-activity when it is first extracted from the mineral containing it. The property develops in a short time if the radium salt is kept in a closed glass tube or similar air-tight container, and its full act ivit y is developed in three or i'( ui!' wi 'eks. It is supposed that the development of radio-activity under these circumstances is due to the storing up of the emanation in the radium. The emanation, which is to be described in detail on a subsequent page, is a sort of vapor which arises from radium. fi cannot pass through glass and passes only very >!owly through a capillary tube, it renders radio-active any substance by which it is absorbed. Radium which is enclosed in an air-t ight container of metal, glass, or rubber, or if covered by varnish preserves its radio-activity unchanged for years at ordinary temperatures. Exposure to the air does not cause any great loss of radio-activity in the case of radium salts which are in the solid state, but it does occa- sion a secondary loss if the radium salt is hygroscopic and absorbs enough moisture to be liquefied. 70 1250 MEDICAL ELECTRICITY AND RONTGEN KAYS Effect of Temperature Changes. Mine. Curie has found that radium loses 10 per cent, of its activity if kept at a temperature of 130 C. for an hour, but that a temperature of 400 C. for only ten minutes produces no noticeable effect. If maintained at a red heat for several hours a radium salt loses 70 or 80 per cent, of its activity. This radio- activity is regained gradually, and at the end of two months or so it is usually even greater than it was originally. A red heat causes the emanation to almost completely disappear from a specimen of radium, and with it the property of inducing radio- activity in other substances. These may be at once completely restored by dissolving the radium salt in water and drying it at a temperature of 120 C. The salt may then have its full property of emanation, caus- ing radio-activity in other substances even before it has fully regained its own radio-activity. Effect of Solution. Dissolving a radium salt causes the liquid to become radio-active, and this radio-activity is not all at once concen- trated again in the radium when the solution is evaporated. The more dilute the solution and the longer the radium remains in solution, the greater amount of emanation is abstracted by the liquid and the less radio-active the radium salt is found when dried. If the solution has been exposed to the air for a number of days, much of the radio-activity of the solution is lost. After evaporation it is found that the dried salt is less radio-active 1 than if the solution had been exposed to the air for a shorter time or had been kept in a sealed glass tube. It also takes a longer time for the radium salt to regain its original radio-activity. Radio-activity seems to be due to the storing up of the emanation. The emanation is not very readily yielded up to solids, liquids, or gases by radium in the solid state, so that in this state it accumulates up to a certain maximum, which is maintained. A solution of radium, on the other hand, very readily parts with its emanation, and. therefore, soon loses a large part of its radio-activity if exposed to the air. Such a solution re- gains its radio-activity if sealed up so that the emanation can no longer escape, but accumulates. The Emanation from Radium. The salts of radium produce constantly and uniformly a gaseous substance, which has already been referred to as the probable cause of the radio-activity of these sub- stances and of the communication of radio-activity to other substances. This gas is also radio-active itself. It accumulates m solid radium salts and makes them highly radio-active. It is specially, from solutions ot these salts unless the solutions sealed glass tube>. and it is rapidly liberated from the solid the>e are kept at a red heat for about an hour "1- \- the one which i> used 1o obtain the eman; nut if ( >r experiment al purposes. o\vs an appara t us for securing t he einanat hum bromid dissolved in water is placed connected at one upturned end \vilh an aspirating ion. At least in a t ulie. J\', tube. There RADIUM 1251 is ;i plug of absorbent cotton in this tube at .4, so that the air drawn through the apparatus contains only the gaseous emanation without possible small particles of the solution of radium. The apparatus in- cludes a water bottle, through which the air enters. Being thus satu- rated with moisture, the air does not cause evaporation of the radium solution. Other parts of the apparatus are a simple aspirating syringe and tubes B, f , and I), which may be drawn full of air saturated with the emanation and preserved for use at any time. Collection of Radium Emanation. The; simple apparatus shown in Fig. 850 shows only the basic idea. In actual practice a large quantity, 500 mg., of radium chlorid at the Huntington Memorial Hospital, and 3 gm. at the Radium Research Laboratory of the Standard Chemical Co., of Pittsburgh, are dissolved in a small quantity of very dilute hydrochloric acid. The vessel containing this, stationary in a safe, has a tube leading out to a complicated system of tubes and bulbs and stop- cocks connected with an air pump. First a vacuum is created in a vessel into which the accumulated emanations water vapor, hydrogen, oxygen, etc. arc allowed to diffuse. Then dried air is admitted to carry this mixture past a mercury seal into vessels where sodium hy- droxid, an electrically heated copper oxid spiral and phosphorus pen- toxid absorb carbon dioxid, hydrogen, moisture, etc. Then this emanation-charged air is compressed into a tiny long tube possibly cooled by liquid air, this compression being repeated every few minutes until all the accumulated emanation has been desposited in the tube, which can then be sealed by heat, and cut into different sealed lengths containing fractional parts of the day's accumulation of emanation. 1 Figure 850 shows a type of apparatus for the preparation of radio- active liquids. One or two mg. of pure radium sulphate, which is in- soluble, are placed in the open upturned end of the tube in the lower bottle of water. As fast as the radio-active solution is drawn off at the bottom of the lower bottle additional water enters from the upper bot- tle. The arrangement is such that no air can enter the lower bottle. Nature of the Emanation. Niton, or the emanation from radium, has an atomic weight, according to different authorities Curie, Ruther- ford. Debierne. and others- -of from 170 to 235. The theory is that an atom of radium loses an atom of helium in order to produce an atom of emanation which, in its transformation, loses three more 1 atoms of helium. Radium emanation is twenty times more absorbed by organic liquids like gasoline, alcohol, and benzene than by water. 1 C. H. Viol, Radium, vol. xiv, No. 1. Oct.. 1910. p. 1. MKDir.VL ELECTRICITY AND KONTCEX KAYS Helium is spontaneou>ly produced by radium at the rate of between 20 to 'JOO ' probably I.")? 1 c.min. a year ))er ^.rani of radium. It is also produced by other substances which emit alpha rays. It is very certain that helium is evolved from radium, and perhaps this is the essential part of the emanation. Helium is a pis lighter than hydrogen: it occurs abundantly in the sun. but only to a very small extent upon the earth. < ^ the twelve characteristic lines in the spectrum of radium, live are al-o common to helium. The volume of emanation in equilibrium with 1 lira m of radium is about ()..")'.) c.mm. 1 The quantity of emanation is jireally reduced by the addition ot different acid- and salt-, such as sulphuric acid and barium sulphate to the solution of radium salt .- Radio-active Emanation Contained in the Air Near the Earth. This i- derived from the uranium, radium, and thorium present in the earth, and it- amount is such that a cubic meter of the air contains an fimount of emanation which would be in equilibrium with SOX10'" 12 uni. of radium. '1 hi.- i> equivalent to SOX 1C : ~ curies. Radium Contained in the Atlantic and lonization of the Air Over the Ocean. .loly has found about 1.1X10 !; .mn. of radium in 1 c.e. of sea-water. The air over the ocean receives an insignificant quantity of u'amma rays and of emanation, but, nevertheless, has been found by variou- observers to have about the same conductivity and number of ions as the air over the earth. Eve 8 regards thi- anomaly a- a serious objection to a purely radio-active theory for the normal ionization of the at nn '-phere. < >nly the purest radium, thorium, and actinium salts y 1 curie of emanation i- about '. H).s electrostatic units per second. A radio-active .-olution is not the same a.- a solution of radium (or a rad i fen HIS solution;. 'I he latter contain- radium, which is constantlv .M: emanation, and in this way it either permanently maintains j'-'-lf in a radio-active state or constantly induce.- radio-activity in -ub-taiices. ,\ radio-active solution, on the other hand, mav -i Mply a -olution in \vhidi radio-activity ha.- been induced liy ab- :. of the emanation from radium. It.- radio-activity disappears ni tins emanation. Kadio-act ive solutions are pre- i ; : immediate use. Itadiferous sub.-tances nil, glycerin, oint- licines on the other hand. ina\' be l.ept for use at aiiv HADir.M 1253 As will be seen later, there is reason to believe that the beneficial activity of certain medicines is enhanced by the addition of radium. Other Electric Phenomena Connected with Radium. .More than once it has happened to Mine. Curie and others that radium that has been long kept in a sealed glass tube has developed a powerful static charge. On breaking open such a tube a discharge has occurred like that of a tiny Leyden jar and the precious particles of radium have been scattered over the floor. A slight electric shock is sometimes felt in the fingers under these circumstances. Robert Abbe in such a case employed an ingenious device for locat- ing the particles upon the carpet. He spread a sheet of sensitized paper over the floor and developed it after the proper time. The paper showed a chart of the position of the different particles of radium. Mereanton, 1 in order to open a tube containing radium without danger of explosion, wrapped around it a platinum wire heated by electricity. A tiny invisible opening was made in the tube, as evidenced by the radio-activity induced in a neighboring piece of metal by the escaping emanation. A control experiment showed that the emanation does not escape in perceptible quantities from an unbroken glass tube. There was no protrusion of the glass at the point where a hole was fused in it, and the experimenter believed that in this particular case, at all events, there was a partial vacuum instead of an increased pressure inside the tube. Absorption of Radium Rays. The rays pass through a vacuum in very much the same way as through the air. The alpha rays are practically all absorbed by 7 or even 3.5 cm. of air. The radiation given out by a specimen of radium enclosed in a small glass tube produces an ionixing effect (in the apparatus for measuring radio-activity) which between 10 and 100 cm. varies inversely as the -quare of the distance. Thus, in one of Mine. Curie's experiments, the current of saturation at 10. 30, 50. 1)0. and 100 cm. was 127. 174. (i.9. 4.7. and 1.115. A sheet of aluminum 0.01 mm. thick, placed almo-t in contact with a thin layer of thorium, transmits 3S per cent, of 1 he original radiation. If radium is used, about 30 per cent, is transmitted, and from polonium or uranium, only 20 per cent . The highly penetrating ray- from radium become practically non- absorbabie after passing through -event I centimeters of solid substance. The alpha ray-, on the contrary, appear to be rendered more ab-orbable after pa -sage through even a thin metallic screen, just as if they con- -i-ti'd of solid particles which lo-t some of their momentum. Absorption of Gamma Rays by Gases and Light and Heavy Sub- stances.- ' >. Chadwick." experimenting with radium rays which have pa ed through 3 mm. of lead 'allowing only gamma rays to pass), finds that liquid air, liquid hydrogen, and liquid carbonic acid gas absorb about 5 per cent . of 1 he lamina rays per centimeter of the liquid 1 ra versed. Water, aluminum, wood, and other li^ht substances absorb from 4' to 5\ pel' cent, and lead about !i per cent, ol the.-e rays per centimeter. Comparison Between the Absorbability of Beta and Gamma Rays. II: 1254 MEDICAL ELECTRICITY AND ROXTGEX RAYS lead, and with increasing thicknesses of lead these beta rays have about the same power as the gamma rays. The gamma rays show a 50 per cent. absorption by 12 mm. of lead, and from there on such a low rate of ab- sorption that some may be demonstrated to pass through even 20 cm. of lead. (lenerally speaking, harder gamma rays emerge than enter a metal with very high specific gravity, and softer with metals of very low specific gravity. Polonium rays undergo a transformation in passing through alu- minum which makes them less penetrating. M. ('uric found that a screen of aluminum. 0.01 nun., and then one of brass, 0.005 mm., thick, transmitted 2' times as much of the radiation as when the same screens were used in the other order, brass and then aluminum. Secondary Rays from Radium. These are similar to those pro- duced by the .r-rays and cathode rays from a Crookes tube. Lead, in particular, gives out these secondary rays in a manner corresponding to the fluorescence of other substances under ordinary light. The secondary rays have less penetration than primary rays, but have an equal photographic effect. A lead filter, arresting the alpha and the more absorbable beta rays, gives out secondary rays which are absorbable and would have an un- desirable surface effect during long application. They should be arrested by a covering of rubber or several thicknesses of gauze. Secondary Gamma Rays. These have the same heterogeneous wave-lentrth as primary gamma rays. Their existence is easily proved 1 iy t he fact t hat an elect roscope behind a lead screen, 0.7 cm. thick, shows the presence of 10 per cent, more gamma rays than when the same lead screen is placed near the radium 5(> cm. away from the electroscope. Florance 1 has measured the quantity of gamma rays emerging from a sheet of lead through which primary gamma ray- emerge, but in a di- rection from which the original ravs an 1 excluded by heavy masses of lead. Studying the properties of these secondary rays, he has come to the conclusion that they are simply diffused primary gamma rays. They may be compared, therefore, to the rays of white light which pass in every direction from t he further side of a sheet of paper held up before a light. Secondary gamma rays produced by beta rays have been demon- strated especially by ,1. A. (Iray.- Delta Rays. These are produced by any source of alpha rays, and are, at least in part, secondary radiations caused by t he bombardment of the substance itself by the alpha particles. They are slowly traveling elect 1 1 in- Luminous Effects of Radium Rays. .Many substances are fluor- under the influence of these ray.- and become visibly luminous in lontr as t hev are held verv near t he radium. Salts ot barium All but the purest and must expensive; admixture of barium salts and hence are Jadium in a very weak mixture with barium tivelv when heated. Pure radium bromid i- c. A diamond held near a specimen of radium nous, and tlii- property sometime- distinguishes illations. Deviation of the beta rays by a magnetic '.tin. KADI I'M 1255 field enables one to obtain distinct radiumgraphs by the gamma rays alone, the object being beyond the carrying distance of the alpha rays. A longer time, of course, is required. A part of the disturbing beta rays is absorbed by zinc sulphid, and clearer pictures may be obtained by mixing the radium salt with a certain percentage of this substance. Radiumgraphs of small animals do not show the bones, since the bones and flesh are about equally resistant to the penetrating rays. Influence of the Thickness of the Layer of Radium. The amount of radiation is greater from a moderately thick layer of a radium salt than from a very thin one. The alpha rays practically all radiate from the surface. Those from the deeper layers are mostly absorbed by the superficial layers. The beta rays penetrate more abundantly from the deeper layers and it is owing to them that a thick layer of radium is somewhat more effective than a very thin one. A layer of radium 0.4 mm. thick gives out only about one-quarter as much radiation as a layer 2 mm. thick. The percentage 1 of beta rays is almost twice as great in the latter case. Radium Rays Lessen the Resistance of Selenium Cell. This effect is produced more slowly than by ordinary light or by the .r-ray. CHEMIC EFFECTS OF RADIUM RAYS Barium platinocyanid is gradually changed from its original apple- green color to a brownish yellow, and this is accompanied by a lessened degree- of fluorescence, just as in the case of exposure to the x-ray. The Sabouraud and Noire pastils for the dosage of the .r-ray are slowly discolored by radium rays. A similar effect is produced upon the test objects in the Holzknecht chromoradiometer, and these are of practical use in standardizing the therapeutic dosage of radium radiation. The impact of radium rays causes a number of chemic changes which ordinarily require some outside influence, such as a high tempera- tun-. \Yater is decomposed into oxygen and hydrogen. Ozone is produced from the oxygen of the air. Oxygen and hydrogen or oxygen and nitrogen enter into combination. The alpha rays are much more absorbable and are also much more active chemically than the beta and gamma rays. Hut in most experiments the alpha rays are arrested by the walls of the container. The effect is like the catalysis, by which we used to believe that a substance exerted a chemic action by its inert' presence without undergoing any modification itself. The penetrating rays of radium cause decomposition of sodium iodid. and Kailan has found' that a solution of Mich a substance in water which contains the ordinary amount of oxygen absorbed from the air is much more rapidly decomposed than when the water has been boiled to free it from oxygen. Radium decomposes lecithin and fatty acids, and its effect upon the embryonic cells and upon leukocyte- and upon tumor cells, all of which are rich in lecithin, is partly at least due to the decomposition of this sub- stance. - The t'tnuncition from rntl/nm decomposes uric acid and other purms. 'Sii/h. Akud. Wiss. Wcin., 1 _'<>. I'.Ul. 2 P. Mi'xTiiitskv. Kmisskv, Vratcli i\. rJ: 12.>l> MF.Dle AL KLKCTHICITY AND KONTCEX KAYS and produces much more soluble substances. Mesernitsky 1 finds that .029 gram of sodium monourate is completely decomposed in twelve days by 50 millicuries of emanation. The glass tube in which a specimen of radium is kept fora longtime becomes somewhat browned by a molecular change 1 . The Spinthariscope.- Crookes has devised a little instrument, con- sisting of a closed metal cylinder with a barium platinocvanid screen inside 1 at one enel and a magnifying lens at the other end. A small particle of radium is placed at the back of a metal disk fastened a short distance 1 in front of the fluorescent screen. Hays from the radium cause 1 brilliant fluorescence in the scree 1 !!. This light is seen to consist of thousands of scintillating sparks, showing the 1 impact of successive alpha and beta particles upon the different crystalline particles of the screen. fluorescent substances exposed to the emanation from radium become' luminous. Solutions e>f radium-bearing salts are luminous. RADIOGRAPHIC EFFECT OF RADIUM RAYS All kinds of radium rays produce an effect upon a sensitized plate. One must enclose' the radium or the 1 photographic plate in se)ine light-proof e-nvelope in order to secure the 1 effect of the 1 radiation apart from that of ordinary light from the fluorescent radium salt. The ravs will pass through substances opaejue to ordinary light and produce radiographs, such as one' of a coin and a key inside 1 of a leather purse. Raeliumgraphs are 1 less sharply defined than picture's by means of an .r-ray tube and take 1 a very much longer time. A fairly gooel radium- graph of a metallic object at a distance of 10 cm. may be 1 obtained in four hours with six seale'd glass tubes of phosphorescent zinc sulphid and barium and radium chloriel, activity 1000. The plate' in this experi- ment is enclosed in five thicknesses of black paper. Specimens of greater radio-activity produce' radiumgraphs in a somewhat shorter time one hour at a distane-e 1 of 20 cm. or one day at a distance erf 1 meter. A pure 1 radium salt of 2,000.000 activity and 20 mg. produces a good radiogram in one or two seconds when in e-ontact with the' black paper em-losing the film. All the- rays from radium affect a photographic film, anel this effect may be used as a measure of the activity of the substance. Two speci- mens, examined under the same, conditions as to distribution over the 1 surface of the applicator, as to the nature and thickness of the' material separating the radium from the photographic film and as to distance, -hould produce the same photographic effect in the same' length of time it 1 hey are ot t he same strength ; and if t wo specimen-- test eel under t he -ame condition- take a different length !' time to reproduce an e<|iial photographic etled. we may know that their radio-activities varv in- , '-r-e!y as I he I hues required. ivs, like ordinarv c;iihode lays, give rise to abundant in passing t h rough a solid subst ane-e, and t hese a re widely is i he cause of the lack of e list inct ne-s m ra< liunigra] >hs. radium themselves lo-e somewhat of their pure \\hite- -e of time, tin.- prohablv being due lo all effect upon the I ifi 'sent as an m i punt v. : [,c H;niiuiii, '.i. I, April, l!>r_'. 1 \~>. RADIUM 1257 THE THEORY OF RADIO-ACTIVITY The radium atom uniformly generates energy in some way which wo can only guess at, and this energy is manifested in 1 wo wavs one, by radiation of rays, both charged and uncharged with electricity; and second, by conduction, /. r., gradual transmission to surrounding bodies in a gaseous or liquid medium by the production of an emanation and induced radio-activity. Alpha rays are charged with positive electricity. Beta rays are cathode or negative 1 particles freed from the radium by the loss of the positively charged alpha particles. The beta rays give origin by their friction with the radium atoms to gamma rays, which are similar to the most penetrating kind of .r-rays. The portion of a radium atom which remains after the emission of the alpha and beta particles is transformed into the gas known as the emanation. The emanation itself gives rise to induced alpha, beta, and gamma rays, and what remains is partly helium gas, which is a stable substance giving rise to no further phenomena, and partly a solid substance (radium A), which causes induced radio-activity and is transformed into radium B. Successive transformations finally result in radium F, which is the same as polonium, and a final stage results in the production of lead. Thorium undergoes similar transformations, the final stage of which is bismuth. PHYSIOLOGIC EFFECTS OF RADIUM The radiation from a sealed glass tube containing 0.2 gram of radium of SOO.OOO activity carried in the pocket of a flannel shirt for six hours produced an ulcer without any pain and which took over a month to heal. This had been preceded by an erythema which developed after a fifteen- day period of incubation. This accident was a personal experience of Becquerel. An accident of the same nature occurred to Mine. Curie; and M. Curie, Dr. Oudin. and M. (iiesel have made experiments upon themselves and upon animals. Ten hours' contact with radium of 5000 activity in a gutta-percha sac caused an erythema, followed in twenty days by ulceration taking four months to heal. Two hours' contact \vith0.3gram of pure radium bromid, contained in thin celluloid, caused ervthema and dermatitis with a raw weeping surface like that following a burn. Complete healing took three months and left a smooth cicatrix like that from a burn. Plate 15 shows the result of an experiment upon my own forearm with my radium applicator No. 1. a sealed glass tube containing about 20 nig. <>f radium of an activity of about 2.000.000. One minute pro- duced no vi.-ible effect: two. three, four, and five minutes produced a more and more pronounced redness and itching with some desquama- tion.but no blistering or ulceration. Thi- reaction was preceded by a period of incub;iiion la-ting about two weeks. The -a me powerful tube of radium enclosed in an aluminum treat- ment t u be. ! mm. t hick and covered wit h rubber, produces a dry redne-- in fifteen minute- and bli-teriiiLi in twenty-five or thirty minute-, as in the treatment of keloid. \Yorking in the extraction and testing of radium exposes one'.- hands 12~>S MEDICAL ELECTRH ITY AND HONTC.EX RAYS to the radiation and sometimes causes dermatitis of the fingers like that from which .r-ray workers suffer. Paul Besson 1 has suffered from slight bad effects after studying specimens of radium for a number of hours. After a week's incubation an attack of rhinitis developed with considerable pain, discharge, and desquamation. He classifies the methods of applying radium by which the skin may be affected as follows: A Single Strong Application. This may be with a specimen of great radio-activity left on the surface for a few hours or one of less activity for many hours. The result is an acute radiodermatitis. Strong but Divided Applications. A high degree of radio-activity applied for a few minutes each day produces a slightly milder inflam- matory and ulcerative effect than the same length of application at a single session. Long and Weak Applications. This method uses very weak radio-activities applied for a long time. Besson says that it does not lead to accidental ulceration, and he believes that it will be the method adopted in the future. Pissareff's classification of the dcyrccs of radiodermatitis from ap- plications of radium is quoted by Besson as follows: Firxt Dctjrec. There is a period of incubation lasting two or three weeks. Then the hairs become 1 brittle and fall out. The skin is left perfectly smooth and may be slightly pigmented. The hair be'gins to grow again in two months and the skin regains its normal appearance. S< com/ l)jrrienl of incubation e>f from eight to twenty-ono 'lays after the application of radium. '1 he more sensitive the 1 skin the susceptible it is to radium, and diseased areas react much more t '.an t he -ound -kin. EFFECT ON MICRO-ORGANISMS 'ericidal effect is probablv due to the alpha rays alone, -hown to act upon culture's /// ritro by Pfeif'fer and Frcid- hoid fever and cholera); bv Hoffmann (staphvlococcus . . Campari has shown its efficiency upon tubercle bacilli thi anterior chamber of the e've 1 and upon diphtheria .: < ;. |{:nlii-activitc. ('.aiithicr-Villars, Paris. 1004. RADIUM 1259 bacilli introduced into the muscles. Injections of radio-active .solutions prevented the infection of the animal by these inoculations. The alpha rays have so little penetration that it may easily happen that only the bacteria in the superficial layers of the culture arc de- stroyed, and that the deeper layers of a culture in a test-tube are not affected by the radiation from radium. Infiltrating the culture with the emanation from radium would in- duce the liberation of alpha rays, as well as others in the substance itself, and should destroy bacteria throughout the culture. \Vcrner has shown that in cases of radiodermatitis the affected tis- sues are not susceptible to bacterial inoculation, and this may be due to induced radio-activity in the tissues. Braunstein finds that bacteria cannot develop in air laden with radium emanation. (Joldberg finds that typhoid, anthrax, and colon bacilli are destroyed by the gaseous emanation. Dorn, Bauman, Valentiner. Kidman, and a number of others have found that radium rays and radium emanation are bactericidal. The minimum exposure to radium emanation required to markedly affect and also to kill cultures of Bacillus prodigiosus have been studied by Jansen. 1 Radiations Tested in Experimental Tuberculosis of the Eye. Radium and mesothorium radiations do not kill the bacilli, though they do have some attenuating effect. They have an effect on the tissues, chiefly the blood-vessels. Ultraviolet rays have verv much more effect on the bacilli.'-' Among the earliest observations are those of Askinass and Caspari, verified by Danysz. 3 A culture of Micrococcus prodigiosus upon agar- agar was not affected in one experiment by exposure to the radiation from a distance of 1 cm. and through a sheet of aluminum 0.10 mm. thick. The same radium salt, activity not stated, completely arrested the development of a culture with which it was directly in contact for from two to four hours. Cultures of anthrax have been destroyed in the same way (Danysz). The latter author and Besson believe that the radio-activity induced in the culture by the emanation from the radium as well as the direct radium rays were operative in this case. The beneficial effect from radium applications in bacterial diseases e. (/., those 1 observed by Tizzoni and Bongiovanni in hydrophobia can- not be attributed to a direct bactericidal effect, because the tissues of the patient would be destroyed by any radium application powerful enough to arrest the development of bacteria in them. The effect of radium upon infective micro-organisms and infection of the tissues has been studied by R. Warner.' Two principal results follow from his researches: First, radium rays may destroy bacteria in certain cases, and in others modify them without developing in them properties Favorable to immunization; >econd. the tissue cells which are destroyed by these rays are capable of pi'oducinir bactericidal substances which are scarcely observed in ordinary autolytic proce-ses. fiir Hyuirm'. Ixvii. 1 :!."">. I'.MO. - Flt'inrniims an.l Krusins. IVut. M.-,l. \Yorh., August ol. I'.tll, KM). : D:in\->z (I'astrur In-titii!c . C'mnpti's llcndc-;. l'rh. Iti. I'.Xi:',. 4 MiinVh. Mc-1. \Vnch.. p. It'rJ."). A'm. _'-'. I'.td."). 1200 MKDH AL Ki.F.eTHHTry AND KONTOK.X KAYS EFFECT ON PLANTS This varies according to the conditions of the experiment. Lilac and chestnut buds are hastened in their development by exposure to radium or radium emanation in November or December, but no per- ceptible effect occurs with an earlier or a later exposure. 1 l>i lit /v///.s- from ratl/iini retard the germination of different grains in proportion to the penetrability of their outer layer and not to their chemic composit ion.- Radium emanations greatly increase the growth and chlorophyl con- tent in seeds and plants. EFFECT OF RADIUM ON TOXINS Sulphate of radium. 20 micrograms per 20 c.c.. left more than thirty days in contact with Ostrovsky's necrotuberculin reduces its activity. Tetanu- antitoxin was unchanged and diphtheria toxin and Koch's bacilli were only slightly attenuated. 1 EFFECT OF RADIUM UPON ANIMALS The radiation destroys infusoria, the larva' of insects, and the eggs of 1 lirds. Animal ferments, such as pepsin and pancreatin. according to Bergell and Braunstein, have their activity somewhat increased, but, according to Ivichet, lactic fermentation is retarded. The venom of snakes (cobra and viper) is destroyed by the radiation or the emanation from radium. That of the land salamander and the common toad is not destroyed. 5 Emanations of radium do not affect the gaseous respiratory ex- changes, the oxygen in the arterial and venous blood remain normal. The blood-pressure is lowered by a vasomotor effect." Small animals which have died afier exposure to radium show con- gestion of the spinal cord and its membranes with submeningeal hem- orrhages. < >ne effect upon the eye is an atrophic retimtis without, change in the cornea or the other ocular media. There are different degrees of susceptibility. The same application which causes ulceration in a guinea-pig will only stimulate the growth of hair in a rabbit. ])aiivs/ found that moderate applications in the case of a mouse produced erythema, with loss of hair and a discharging surface, but no general ills! url ia nee. b .posim; to radium of vi ry great activity caused convulsions, paral- 1 . and death in about ten days without surface lesions. The fatal - are produced bv the gamma rays and by the most penetrating ' of ! he be i a fa vs. Tlii- effect is analogous to that of t he X-ray. I nei nus system in thesmallest animals is covered by only transparent bones and soft tissues, through which \ - ma v act . UADIl'M 1201 In the human being, on the contrary, these vital organs are protected by tissues, through which practically none of the physiologically active ravs of radium can penetrate. .None of the resulting nervous symp- toms occur in man from radium applications, although they arc not so very unusual from exposure to the radiation from an ./'-ray tube. Young animals arc much more susceptible to the fatal effect of radium applicat ions. lleinecke has found the wall of the intestines in small animals de- stroyed through the intact abdominal wall. The lymphatic glands, the spleen, and the thymus gland atrophy after exposures which do not injure 1 the skin, lleinecke and Selden find that radium has an effect like the .r-ray in producing sterility in men and women as well as in animals. Ten or fifteen minute.-' application of very active radium is followed by development of an acute eryi hema in 1 \\cnty-fotir or forty-eight hours. No experiments have yet been made with the alpha or beta rays sepa- rately to ascertain their physiologic effect, but a screen of sheet lead has been used in applying only the gamma rays. Such a therapeutic appli- cation may take a number of days. Pic/mentation from kiing seven to sixteen days, follower! by con- junctivitis, iritis. a;id superficial or interstitial keiatitis (inflammation of the come_a). There was inflammation of the e-yelid with loss of hair 1 .1. ( >. \V. Barratt. Quarterly Journal of Kxperimental Physiology, 11 1. 2t'>l, 19K>. - Ti/xoni and Boiifiiovanin. Rii'orma Medira, July. 190."), p. sis. "' Aivhiv. f. Ophthalmologir. vol. lix. pp. L's7 -:ji)ti; reviewed in l,e Uadium. Sept. 15, 190."). 12(12 MKDICAL KLKCTHICITV AND K(")NT( iK\ HAYS and ulceration. There was often atrophy of the optic nerve, walls of the blood-vessels were hut slightly affected. The retina was decidedly affected and in the same way as by the x-ray, not as by the ultraviolet ray. The lesion was a degenerative one, chiefly of the ganglionic cells. The optic nerve atrophy was secondary to this. There was no inflammatory change in the retina or optic nerve. Subjective troubles with the eyes have been noted after studying specimens of radium for too long a time. The eyeball should he pro- tected by heavy metal or lead-glass shields when radium is applied to the eyelids in therapeutics. Wichmann 1 has made experiments upon the absorption of radium by the skin and other tissues. The normal skin arrests two-thirds of the radiation, most of this being absorbed by the derma and very little by the epidermis and the subcutaneous fat. Abnormal tissues in general, such as lupus, cancer of the breast, and fibromyoma of the uterus, ab- sorb from 50 to 100 per cent, more than adjacent healthy tissues. This may very probably be the cause of an apparently selective action of the rays upon morbid tissues. The greater part of the rays being quite absorbable, a special arrangement of metal or other screens is required to produce an effect upon the deep tissues without undue action upon the skin. The screen is to arrest the absorbable rays while permitting the passage of the highly penetrating rays. Wichmann's experiments, including l.'i microscopic examinations, do not confirm the usual statement that there is a primary effect upon the inner walls of the blood-vessels. .1. Sehlacta 2 has experimentally studied the similarity previously reported by Werner between the effect from inlradermal injections of lecithin and that from exposure to the radium rays or the x-ray. The conclusion may be drawn from his experiments thai, while these in- jections will cause alopecia and ulceration just like that from the radiation, we do not. yet know the precise nature of the chemic products generated in the tissues by the radiation. EFFECT UPON ANIMALS DURING THE STAGE OF DEVELOPMENT AND GROWTH Tissues or organisms of slow growth appear to have their growth retarded by exposure to radium rays, while those of rapid development are either destroyed or the growth is slowed or quickened, according to the nature of the different tissues. PATHOLOGIC EFFECTS OF RADIUM The change- in the skin appear to be analogous to those resulting from the ./"-ray; they require a longer application, bul are more intense. Slow degenerative change- take place in the cellular elements of tl in. e.-pecially t he cells of the epidermis, and. to a less extent , the cell- ni the glands, blood-vessels, and muscle.-. ( onnective tissue is not SO HIM r j here i a secondary congestion and extravasation of serum and Jeukocyti . The legion- in the blood-vessels are chiefly responsible for the verv -low healing when ulceration occurs. RADIUM THERAPEUTIC USES OF RADIUM 1. The mildest applications modify the nutrition of the tissues and stimulate the growth of hair and the activity of the glandular elements. They may be useful in cases of atrophy, atony, or ulcers of the skin, and in ophthalmologic and gynecologic cases. 2. A more or less destructive effect may be produced upon such affections as epithelioma, lupus, nevus (birth-mark), verruca (wart), keloid, and a variety of other localized conditions. Administered internally, solutions of radium modify morbid condi- tions of the Castro-intestinal canal and other viscera and produce a systemic effect. The latter may act as an adjunct to other medication. Inhalations of air laden with the emanation from radium have been used for an effect upon tubercular processes in the lungs and air-passages. APPARATUS FOR THERAPEUTIC USE OF RADIUM There are two forms of apparatus for applying the radiation from radium. In one the radium is placed in a shallow cavity and covered by a very thin screen of gutta-percha, aluminum, celluloid, or mica. In the other the radium is mixed with a suitable waterproof varnish and fixed upon the surface of the instrument. The latter method has many advantages. Danne's varnish transmits GO per cent, of the radiation, while the thinnest kind of a screen transmits only 10 per cent, of the radiation, and even this does not include the alpha rays. Radium Applicator with a. Screen. Fig. 851 shows the usual type of apparatus. The shallow cavity is either 5, 10, or 15 mm. in diameter, A Fig. NJ!. Radium applicators: .1, A'-rudium cell covered by mica; H, radium applicator to fit on a rod. and is said to be filled with either 0.01, 0.05, or 0.1 gram of radium. The activity of the latter may be from 50.000 to l.XOO, 000, the cost of the instrument and radium varying accordingly from 825 to $S(JOO. The higher activities require only a few minutes' application, during which the patient may hold the instrument in position. The radium is usually held in contact with the surface to be treated, separated only by the thin screen of the apparatus. As it is difficult to thoroughly dis- infect this after use, a better plan is to stretch the thinnest kind of rub- ber, not nearly the thickness of paper, over the entire instrument. This rubber may be renewed each time The lower activities require long applications and the instrument had better be secured in position by adhesive plaster. Apparatus with Radium Secured by Varnish.- One type of in- strument is shown in Fig. S51. The surface of a metal disk is from 10 to 25 nun. in diameter, and is coated with varnish containing from 0.01 to ().()() gin. of radium of from 50.000 to l.SOO.OOO activity! The instrument and the radium cost from 825 to 85000. A little tube at the 1204 MKD1CAL KLKCTHICITV AND KONTGEN KAYS back of the disk serves to receive a rod acting as a handle or a cord by which the disk may be bound in position. The radium-coated surface i- UMially placed directly in contact with the part to be treated. It disinfected after use by washing in vottr. or 1 per cent, solution xxi am pernuuujanatc: or hydrogen peroxid, or / per cent, sodium iti or (ili/ciri/t. or / fier cent, tncrcurij b/chh>r/(l. Exposure to foi'inaldehyd fumes is an excellent method. Boiling in water for a few minutes does no harm, but alcohol and (the)' are to be avoided. An ulcerated surface, whether malignant or not, had better be covered with aluminum foil. - ,,',-,-, or T |ju nun. thick. This protect > the instrument from contamination and arrests only an insignificant part of t he radial ion. Other instruments are like those shown in Fig. So2. where the radium is varnished upon a thin piece of metal attached to a long stem with a joint, by means of which it may be adjusted in any posi- tion. Tln> may be applied not only upon the sur- face of the body but also to many of the mucous meml >ranes. Others are metal cylinders coated with radium- varnish. These may be straight, curved, flexible, oi' jointed, for application to the eye. ear. nose, throat, urethra, or uterus. Narrow strips of celluloid varnished with radium mav be introduced into punctured wounds made in the substance of a malignant tumor. Radium-coated celluloid in flat surfaces or as bougies ' Fig. S"v> ) are chiefly employed by the aut hoi 1 . Radium-coated Cloth.- This is fastened upon the surface to be treated in cases requiring a long application. It contain.- 0.0'J .mil. ot radium per xpiare centimeter and of a radio-activity varying from .")()( to 10.000. It costs from si to S.I1 per >(|Uai'e centimeter. 1 he surface is varnished and the cloth mav be used any number of times. ( Ila>- lubes containing radium are unsatisfac- tory for therapeutic purpo.-e.-. The glass arrests a very large proportion of the rays and is liable to breakage. Protection of the Neighboring Skin.- Sheet lead. 1 or 'J mm. thick, may be used when the ap- vere. A hole of the proper H/e allows the rays to I he diseased area, but the fact, that the radium is at i~ to 'he 1 ime of exposure. RADH'M 1205 Crusts, scabs, pus, or other secretions should he removed, as well as hard portions of epidermis. They would all tend to ahsorh the most active' ravs and reduce 1 the therapeutic effect upon tissue cells. Longer applica! ions may he made upon ulcerated surfaces than upon unhroken skin. THE DOSAGE OF RADIUM RADIATION The quantity of a radium salt should he 1 or 2 eg. per square centi- meter. The duration of an application depends upon the radio-activity and whether there is to he one application or a series of them. It must also he remembered that this is an agent of which some specimens sold for therapeutic use may not prove to he of specified radio-activity. The dosage given below is intended merely as a general guide, to he verified by cautious trial of each particular specimen of radium. Xo harm at all and only a trifling delay can result from too weak applica- tions, while very great suffering may follow too strong ones. A radio-activity of 500,000 may he applied for an hour a day for six or eight days in order to produce a superficial destruction and an obliterating effect upon the blood-vessels in angeiomata. Weaker specimens would have to he applied for a correspondingly greater length of time and stronger specimens for a correspondingly shorter time. The intense destruction required in the caseof commencing recurrence of carcinoma of the breast, when it is still quite localized, ma}' be ob- tained by the application of radium of 500.000 activity for an hour a day for twelve or sixteen days. The same effect would be produced by the application of a specimen of 100. 000 radio-activity for two or three hours a dav for twentv or thirty days; or. on the other hand, three or tour applications of six to ten hours each with an activity of 500,000 will produce this effect. ' The mildly destructive effect required in lichen planus may be ob- tained by applications of a radio-activity of 500.000 for an hour each day for seven days. Localized scaly prurigenous eczema is favorably modified without destruction of tissue by 500.000 radio-activity for two minutes three times a week, or 100,000 radio-act ivity could he applied once for half an hour. Urethral or uterine applications of an activity of 500.000, lasting ten minutes and repeated three or four times, produce an alterative effect without destruction of tissue. An activity of 100,000 would require three or four applications of half an hour each. Applications for intercostal and other neuralgias and for herpes zoster may he made with an activity of 500.000. applied for ten minutes at a time tor four or five successive days. Dosage of Radium in Medicinal Substances for Internal Ab- ministration. Kach irram of the medicine contains a measured amount of pure radium bromid, varying from ' to 10 micrognuns f n , 1 IM , ing.). Kadium drinking-water is beneficial in trout and rheumatism and Radium-bearing quinin in t he treatment < if olist in; tion of being beneficial in internal cancel SO 1266 MEDICAL ELECTRICITY AND RONTCJEN RAYS A pill containing radium oven in this very small amount will affect a photographic plate if left directly upon it for twenty-four hours. Other medicines to which radium is added to increase their special effect as well as for its own properties are mercury, arsenic, digestive ferments, sodium nitrite, and various medicinal waters. Intravenous Injection of Solution of Radium Suit*.- One milligram of radium intravenously causes a very rapid fall of blood-pressure and death in a few hours, ('ameron has noted a beneficial effect upon the blood-pressure and blood-picture from a single intravenous injection of .")() to 100 micrograms. Ho has not soon much effect in diabetes or chronic nephritis, but good results in chronic and subacute arthritis and myelitis. Three weeks after an intravenous injection, if death occurs, considerable radium may still be found in the bones and marrow. Dosage of Radium in Mixtures for External Application. Oleato of mercury and mercurial ointment may receive an admixture of 1 micro- iiram of radium per gram. This is said to enhance the specific effect of the mercurial inunctions and dressings. Radium ointment is made of lanolin or vasolin. or a mixture of both, and contains from 1 to 10 micrograms of radium bromid per gram. It has been used in carcinoma, epithelioma, and for rheumatic pain. Radiferous glycerin is made by actually dissolving the radium bromid. while the ointments are mechanical mixtures containing solid particles of the radium salt. The emanation is given out very much more freely by radium in solution. This makes the solution more effective for the same percentage of radium. It must, of course, be kept ;n a seulod crlass container when not in use. It has the same uses as the ointment, and is especially adapted for gynecologic application. It con- tains trom .,',, to 10 micron-runts of radium per gram. Radiferous, water may bo prepared of any strength, from in'oir t 100 micron-rams per gram. A strength of from \ to 10 micrograms has been used as an injection in cancer cases. A strength of ^ ,,'-(,,, micro- ti'ram per gram mav be used as a beverage and is more radio-active than the majoritv ot natural mineral spring waters. Radium-bearing plain water or mineral water preserves indefinitely the property of radio-activity, which in the natural radio-active spring Wat'-!'- is onlv an induced and vorv temporary quality. Baths of Radium-bearing Water. These may be prepared of greutor st rength than t he nat ural radio-act ive spring waters and may be Used at home us the radio-act ivit v is permanent. The Dosage of Radium in Terms of Holzknecht ,r-Ray Units. K\ posing a 1 lolxknechi I ablet to radium of 7000 activity t h rough a thin iroduced by twelve hours, and 10 II. by twenty- 100 produces ." II. in fifteen minutes and 10 If. lire radium bromid. radio-activity 1>00. ()()(). MI' es and 10 II. m 1 en m unit es. ilxknecht units from radium treatments over II. RADIUM 1207 Oudin has in his possession a specimen of radium of 1,. 500,000 activ- ity, which takes an hour to produce 3 II., but which will produce an erythema lasting a month from a fifteen-minute application. 1). 1). (Danlos ?) in Le Kadium, Sept. lo, 1900, reports the use of a 1 eg. square of copper with 1 eg. of pure radium sulphate incorporated in a varnish. To test the dosage he applied this to different places on his forearm for from five seconds to fifteen minutes. A two-minute application was followed after a very variable period by a slight red- dening of the skin. A ten-minute application led to an actual ulcer, requiring two or three months to disappear. Dosage of the Emanation. Inhalations of air laden with the emanation from radium should be prescribed with caution. Small animals which are allowed to breathe only air pretty well saturated with it die very quickly from its effects. It seems to the author that the best method is that by which the emanation-laden air is very largely diluted with ordinary air. The ordinary screen radium-applicator may be used for this purpose, remov- ing the protective sheet of metal, celluloid, or rubber, and applying a few drops of water to the exposed radium salt. The apparatus may be held within a couple of inches of the open mouth and nostrils. Only the greatest radio-activities give off sufficient emanation. The other form of apparatus for utilizing all the emanation (p. 12ol) must be used with caution. Seventy milligrams of radium supplies enough emanation for the treatment of an entire roomful of people in an emanatorium. Inhalations of the emanation may also be made by inhaling air, which has to bubble through a solution of thorium nitrate, but these are very weak. 1 ing. of radium giving out as much emanation as 20 pounds of thorium. The curie is a quantity of emanation which is in electric equilibrium with 1 gram of radium. The practical unit of emanation either for inhalation or in solution is the microcurie or one-millionth of a curie. The wachc unit, formerly used, represents the electric energy in volt hours multiplied by 1000. A common dose of emanation is a liter of water containing 000 mache units, and this may be given several times a day. About 2.~>00 mache units equal 1 microcurie. The number of mache units in a glass of water may be directly measured by a special electroscope called the fontactoscope. Tubes of emanation (dosimetric) are sold. They are full of air as "oniplt'trly saturated as possible with the emanation from pure radium bromid. They are either capillary glass tubes or hollow needles. They are specified 1o contain a certain number of millicuries and are equal in effect to thai number of milligrams of the purest radium. Hut their radio-activity is very quickly lost and is reduced one-half in three < >r \< >ur days. ler subcutaneous injection ot ."> or 10 c.c. of water emanation t he t issues of t he (Mil ire body and even to be radio-active. This extremely rapid diffusion n l he case of oil sat u rated wit h the enianat ion, which, a si ronger local effect . Experiments by the Author Februray 24, et seq., 1904 > with a Solution Exposed to the Radiation from Radium.- The solution was made by immer-um' a sealed lilass tube conta (i ll2t')S Mi:i)I( Al. KLKeTKHTrV AND H<">XT< I KX RAYS i(i. (I pel 1 cent. XaCl) for fourteen davs. The \vhole was kept in a small iron safe \vei;hin; 7~i pounds. Tested in a variety of ways this solution seemei 1 not to be radii i-act i\'e. The solution was not luminous in the dark. It was not fluorescent when exposed to f;asli. /. -March 5. I'.iOl: A cat \veiji'hinji '_' I 1 ."> Lnn. received in the back a hypodermic injection of \ ouii''e of t he above solut ion. A ral>bit \\cmlnnL!. !*!)() ;j.'m. recei\"ed a similar injection, ', ounce of the same solution. Neither of these produced any local irritation, but there was slight temporarv intestinal trouble in the cat. Ej'fit i-imi nl .\u. -'. March 1 1. I'.lDl: A do^- weiu'liin.u' about UK!! 1 uni. was ethei-i/.ed and the riirht carotid arter\- \vas o pencil and connected wii h a manometer which registered the ire.-r-ure upon a chart. '1 he lett femoral vein was incised, and at re, of the above .-oluiioii was injected. A lew minutes later a iiinl of the solution was injected. I lie do^ \\'as not incon- in any wav at first, and was presented at a meeting oi the ition of the (ireatei' ('it\' of \eu \ ork a few e\-eiun.L;s ' lime he trott ed a round. \\ a ,'j '_: m ^ his tail, and apparent ly i'h. but he died a fe\\ days later, evidently in coiisecjiienci. 1 h. bui ' , ' ,vh\ it was difficult t o say. i-nts ilescribi'd above the only symptoms at the ;m \' i re tliu.-e direct Iv at t rilnit able to the saline solu- Hi o| bloii(l-|!res.-iire. There were none a] >par- KADI I'M 12(i ( .) RADIUM THERAPY '1 his consists most commonly in the application of a radium prepara- tion as directly as possible to a local lesion and leaving it in contact for minutes, hours, or days, according to the radio-activity employed and the extent of the tissue changes desired. The more filtering material is interposed to arrest the less penetrating rays, the longer the application may last and the greater is the deep effect secured. RADIUM IN THE TREATMENT OF LUPUS A radio-activity of 20,000 is applied for about twenty-four hours and causes ulccration, which heals slowly and leaves a cicatrix having a natural appearance and probably completely free from lupus. This is the ulcerative method as distinguished from the dry method. The latter method seeks to modify the diseased area without destruc- tion of tissue. Radium of an activity of 200,000, 300,000, or 1,800,000 (pure radium bromid) may be used in applications of from one or two to five or six minutes each day for several days. A irlass tube containing 20 mg. of a. radium salt of 2.000.000 activity owned by the author can be applied five minutes only once in three weeks to any particular spot, but if filtered by -j* mm. of aluminum the applica- tion may be either three times as long or may be made once a week. The results have not been so good in deep ulcerations from lupus or where the mucous membrane of the nose or mouth are involved. Radium is applied especially to the nodules left after Rontgeno- therapy, Finsen therapy, or other treatment, and which are often the site of recurrences. RADIUM IN THE TREATMENT OF SKIN DISEASES Verruca.- Young warts yield readily, but older ones may be resist- ant even if the horny layer is cut away. The exposure should be equal to four minutes with an activity of 1,800,000 and a weight of 10 or 20 mu\ Radiodermatitis. The author's own hands and face and numerous other case< which he lias successfully treated were cured by applications of a u'la tube containing 20 mgm. of 2,000,000 activity for thirty minutes or so. 1 lol/knecht has cured about .">() castes by a different method which applies only the iramma rays. A flat applicator i- coated with 4 mii'in. of radium per square centimeter of applicator surface. The filters used are 0.2 mm. silver. 1 mm. aluminum. 1 mm. copper, and a thin layer of cotton. The duration is from one and a half to eiu'ht and a half hour-. Eczema. Radium has not -ucceeded as well as the r-ray in ec/ema and prurin'o. It is only to be recommended for -mall chronic and very circumscribed area-, especially about the hands and fingers, which have per ha ps failed to re-pond to the .r-ray. < >n< 1m ha- cured an old case oi nniriui- ani by two ten-minute applications ten days ap^rt. The radio-activity was 1 .soii.iliiit. wiLrhi 2-~> mu'.. enclosed in glass and alum- inum, allowing .,',, <>f the total radiation to reach the -kin. This fraction con-isted practically of iramma rays. Another method is 1n Use a -heel ot' celluloid Y;i I'll 1-1 led with a 1'ei lllcei 1 HI ( 1 io-a ct IV i t y a ! 1 1 ! separated from the -kin by pa ratlin paper and held in place for some hour-, or until the appearance oi a -liu.'hl reaction, by strip- ol adhesive plaster: recurrences arc' prevented in thi- way. 1270 MEDICAL ELECTRICITY AND RONTGEX RAYS Psoriasis.- As to psoriasis, radium therapy is indicated for patches upon the face and about the nails. According to Helms, a two- or three-minute application of 1,SO(),000 radio-activity to a patch of psoriasis causes reddening followed by dis- appearance of the spot . The results so far have not been gratifying in xycoxis (but Blaschko reports o cures out of ti cases), acne, or inipctiyo. Radium Proposed for Hypertrichosis.- A plaque 1 inch square coated with 20 mg. of radium element is used and recommended by Dieffenbach. 1 The hair is first removed by forceps: for young persons the radium is left in place over a zinc oxid plaster, as a filter, for one hour, and possibly for two hours in women over fifty years old. In- tense dermatitis results, with a crust that falls off in three or four weeks. The margin of the lip must be shielded by thick lead. Telangiectases sometimes result from the application and require catelectrolysis for their removal. The author's experience shows that a glass tube con- taining 20 mg. of radium element can be used in the same way: moving it to different parts of a square inch area with the adhesive plaster filter; the author would not advise more than twenty minutes for the first application. The final effect of this should be observed before treating other areas. Radium has the great advantage of accuracy of dosage 1 and accurate positioning, but. like the .r-ray, it presents some uncertainty as to per- manent destruction of the hair and as to freedom from a red shiny after-appearance of the skin. My judgment would be that an operator should gain his first experience ujxjn some hairy part of the body, and not until he has obtained results there which would be entirely satis- factory to the patient should it be used upon the face. Pigmentary nevi require an ulcerative effect, but raxculur ncri det;i rays are absorbed bv a sheet of rubber i mm. thick. I he i arise from this are diffuse rays of slight penetra- nt their reaching the skin an additional covering of A di-k I) cm. in diameter, coated with 0.10 gin. of activity, is applied for two hours over each ol lour out the joints on the same day. The same applica- \inf-i I' n| 1 1< >IM< -opiitliy. al>-t. AtinT. .Imir. Klrctrollirrupv and ,-(.!. \\xvi. No. I. p. i:..l. RADIUM 1271 tions are made over other areas on the following day, and still a third series of four applications is made over other areas on the.jsucceeding day. Two of these applications over the same areas would cause only a slight erythema without any bad result. Wiekham and Degrais have shown the increased benefit derived from applications of very great strength through lead \ inch or more thick and lasting forty-eight hours. MALIGNANT DISEASE Robert Abbe, of Xew York, has published the case of a child with apparent sarcoma of the jaw cured by radium. This is about the only supposed case of truly malignant disease which has been cured. Weaker and longer applications appear to be the best in cancer cases. C. Esdra 1 reports the cure of an endothelioma of the face by appli- cations of radium bromid :> nig. were used thirty-five times, for an average duration of thirty to forty minutes each time. Epithelioma. All forms of ''benign" superficial epithelioma ulcerative, papular, or exuberant are cured by comparatively mild applications of radium. Malignant epitheliomata, like those of the lip and tongue, are benefited, but so far have not been cured by radium, and the same is true of carcinoma. A. Blasehko- finds that there are some recurrences after "euro" of epithelioma by radium (one personal case). Ulcerated forms are more accessible than non-ulcerated, but the latter can be cured without de- stroying the skin (young proliferating cells being more susceptible). Darier 3 treated a case of recurrent epithelioma of the cheek, the side of the nose, and the upper eyelid by applications of radium 5 mg. of radium sulphate (activitv 500, 000) varnished on a copper plate 25 mm. square was applied for thirty minutes to each of the three lobes of the growth. These applications were repeated three days later and every eight days thereafter. The subsequent applications were 1 over different scattered nodules, which represented invasion around the growth itself. The tumor fairly melted away (in ten days), and healed without any scar tissue and with the loss of only a small portion of the tarsal can ilago. McKen/io Davidson reports J4 cure.-, of rodent ulcer (epithelioma) by the application of the radiation from radium enclosed in a glass tube. 1 Francis II. Williams and Samuel W. Fllsworth' use a capsule con- taining 50 mg. pure radium bromid covered with celluloid for skin cancer, etc. It is applied two to ton minutes twice a week, moving it about to secure uniform action. K. Sch iff' reports 2 cases of opitholioma of the face cured by radium. Ho believes that excision should be resorted to if prompt improvement doc- not follow radium or .r-rny applications. Radium Dosage in the Treatment of Epithelioma. Kpithelioma requires applications equal to a -ingle one of about ten minutes with pure radium bromid, activity l.SOO.OOO, weight 10 mg. 1272 MEDICAL K1.K( TKiriTY AM) HOXTC.KN KAYS A Case of Recurrent Fndothelicma of the Vestibule of the Vagina (Fig. S/V4).- The disease had recurred very promptly after operation and in three weeks had regained its original size, about 1 inch in diame- ter. Secondary infection had required the removal of lymphatic glands in both groins and these also had recurred. The author's treatment consisted in the application of radium-coated celluloid with a radio- activity of 2"), 000 for from ten to twenty minutes, once in eight to fourteen days, to the vulvar tumor, and applications of the .r-ray to the inguinal glands. There seemed for about two months to be an arrest of the progress of the disease. The vulvar tumor became flatter with- out any apparent change in breadth. Then there came a time when the tumor gradually increased in size and an irritating discharge began to flow from its surface. During the course of treatment, which extended over a period of about four months, there was no material extension of u'. s -">4. Kii'lnt hrlioma of the vulva. Treatment \>\~ radium and the .r-rav did not the inguinal enlargement, but the patient's general condition gradually became worse. She abandoned treatment then for the purpose of seek- in LL the benefit of count ry air and a va cat ion from her duties as a school [principal and died in a couple of months. The case was referred to the tthor b> Dr. Hoag. A Case of Disseminated Carcinoma of the Breasts and Axillae Treated bv Radium. The man ~ho\vn in Plate K \vas referred to the author bv 'ler. I he right mammary gland and nipple had ulcerated away and \:i~ another ulcer below that region. Hoth were adherent and ci i id n red parchment -like epidermis, and were surrounded IA !'. ' ' i margin project um' ', inch above the level of I he >kin. (ilandulai larger than a hickory nut but -mailer than a hen's eu. ( i \ven Mih axilla' and were widely >ca I tered over 1 he front of the cli riirlit -ide of the che~t the >kin over many of these; was red. and ':,< \\.rr<- evidently i" '' wav to break down into ulcers. P1.AIH RADIUM 1273 On the left side the nodules were' smaller, white, and extended from the nipple in a cord-like mass up into the axilla. The disease had been of several years' duration; no operation even for removal of a microscopic specimen had been permitted. There was no history of syphilis, and two careful \\assermann examinations were negative. The clinical diagnosis had always been carcinoma, and if so, it was evidently similar to the cases of epithelioma cicatrizans, which are sometimes active for as long as eight years before causing death. My patient had lost weight and strength, the skin was adherent to the chest wall, and the use of the right arm was interfered with. Treatment was by contact applications of 20 mg. of radium of 2, 000, 000 activity in a sealed glass tube -, :i n mm. in thickness, enclosed in aluminum \ mm. thick and in thin, soft rubber. Treatments were three times a week for a month and after that once a week. At each treatment several individual nodules or parts of the nodular borders of the ulcers received an application equal to a total of fifteen minutes in each place. During the first month every growth on the right sick 1 had been treated in this way, and also the floor of the ulcers, but the left side had not been treated. At the end of this time all the nodular masses on the right side were perfectly flat, the cicatrized ulcers were no longer adherent, but could be raised and bent double. The arm could be raised to the greatest extent. The patient felt stronger and had gained 5 pounds in weight. The left side, untreated, showed marked improvement, strengthening the author's belief that the application of the .r-ray and radium rays to cancer develops some 1 antibody, which is carried through the system and in proper dosage produces benefit to cancer foci beyond the effective reach of the direct rays themselves. Treatment was begun upon the left side, and the subsequent course of the case has been one of steady progress. For a cancer of the jaw in a delicate old gentleman with heart disease, an entirely unfit subject for resection of the jaw, two applications of a tube of radium placed right in the broken-down cavity in the jaw-bone will effect a symptomatic cure. The glass tube, containing 20 mg. of 2,000,000 activity, should be enclosed in an aluminum treatment tube, and this may be applied for a total of from twenty to forty minutes, de- pending upon the destruction of tissue which is considered desirable, in addition to the specific effect of the gamma rays upon living cancerous tissues which are to be converted into living healthy tissues. If no destruction of tissue is desirable, a lead filter may be added and a soft rubber covering, and t he length of time or t he quantity of radium greatly increased. Fuimatinu' epitheliomatn are usually treated by 'U'ickham 1 by direct contact, except for a thin rubber covering, with a flat disk varnish ap- plicator, 1 inch in diameter, containing 10 mg. of pure radium salt with a certain amount of barium and other impurities; its radiation consists of ( .M) per cent, beta and 1(1 per cent, gamma rays. This is applied for an hour at a time every third day until about thirteen applications have been made. Stronger radium m>trument>. like glas.- tubes containing '_'() or more milligrams of t he pure radium salts, are effect ive with shorter applications, and. of course, weaker instruments require longer applica- tions; but in any case the destruction of fuim'ating epithelioma make- j;rais. UadimnthtTapy. Kndish LMition, published by Funk A: HUH. ;ni fin icli-niakinir \v<>rk. 1274 MEDICAL ELECTRICITY AND RONTGEN RAY'S an unfiltered radiation desirable. The destruction is a molecular one, not accompanied by sloughing. Kpitheliomatous ulcer of the side of the nose which had not healed permanently by .r-ray or cautery was treated by Wickham with an apparatus varnished with 10 mg. of pure radium salt, covered with T ^ - mm. of aluminum and 1 cm. ( , 4 inch) of cotton-wool as filters. Seven applications of one hour each, spread over a fortnight, were followed by gradual closing up and healing of the ulcer without any inflammatory reaction. The cure is apparently permanent. Small idccraihnj and crust-forming epithelioma has been treated by Wickham with ~\ mg. of pure radium salt without any metallic filter. Five .applications of forty-five' minutes each were made in the course of seventeen days. Decided reaction followed, with the development of a crust which, where it came away, left a perfectly sound surface appa- rently permanently cured. Papillomata and senile warts are easily cured by a single strong application of unfiltered radium rays. The author has treated many cases of epithelioma of the face by a single application of 20 millicuries filtered only by the glass wall of the tube and the thinnest rubber tissue or paraffin paper. Twenty- five or thirty minutes ordinarily results in a permanent cure with- out any scar. If there should be an incomplete removal or a slight recurrence, another radium treatment will be effective. The skin around the lesion is protected by lead T ! t) inch thick. The Mayos say that this treatment is preferable to surgical removal. Carcinoma of the face with extensive swelling and ulceration was greatly improved by Wickham under applications of GO mg. of pure radium salt through a lead filter 2 mm. thick for seventy-two hours over the center of the mass, and 15 mg. through the same thickness of lead over all other parts of the growth for fifty-two hours each. Epithelioma of the parotid region was successfully treated by Wick- ham, using a cross-fire method by surface applicat ions of four inst ruments containing 25, 25. 10. and ~\ mg. respectively, filtered by 1 or 2 mm. of lead, at different parts of tin- periphery all night for a fortnight and changing to other parts of the skin each night. Besides this an unfiltered application of 50 mg. was made over the ulcerated center of the growth for three hour- altogether: and. in addition, a radium tube of 10 or 20 mti'. of 1 he pure salt screened by 1 or 2 mm. of lead and giving only highly penetrating rays, was inserted into the substance of the growth for four periods of twenty-four hours each. The growth broke down and -loughed out through t he ulcerated place, and its base became movable, whereas it had formerly been adherent. Cancer of the Breast. Wickham's experience shows thai it is better not t,, expose the lung to too much radium rays, but to use a cross-fire in 1 ' ' nd. )! ven when the -kin is red and looks like an abscess 1 he e fleet of radium may be obtained without ulceration by a cross-fire method with 2 mm. or more of lead and long application.- of strong specimens. \\if*kham's u.-e of radium in cancer of the breast is confined to the following ea-es; 1. "\\ hen the patient firmlv refuses an operation. 2. "\\hen the surgeon founders the case inoperable. '>. ". \Jfir complete -urirical removal if there are enough very power- ful radium in-t ruments t , , cover a la rtre ext ent of the surface; ol herwise. UADITM 1273 the .r-ray is more effective. Sometimes in a young patient refusing mutilation by the loss of the breast, the surgeon may remove the whole subpeetoral and axillary chain ami the breast itself be treated by radium." Figures S .")."> Mil) >how tin 1 beiirfirial effect in a case of tumor of the orbit diagnosed as sarcoma. The patient \vas referred to the author by 1 )r. ( leo. II. \\f\\. A d iff i 1 rent pail of t he t umor received an hour'- a]>p!i- cation once a week for a total of twelve treatments. A 20 mu'. tube (>t 2,000.000 activitv was enclosed in an aluminum treatment tube, niid 12il> MKDICAL KLKCTRH ITY AND HOXTOKN RAYS that iii thin .r-ray metal, and that in thin rubber. After the complete disappearance of the tumor the eyeball, which was sightless, was re- moved as a matter of precaution. Applications of very powerful specimens of radium have been re- ported by Cameron, of Pittsburgh. lie saw very great temporary im- provement in a case of cancer of the rectum from applications equal to 200 in"', of radium screened by 1 mm. of lead, and "Teat reaction, fol- lowed by improvement after eight treatments of an hour each, in a case of cancer of the laynx. He has observed the same toxic condition noted from .r-ray applica- tion- upon a large cancerous mass, and it is sometimes even fatal. Cau- tion must, therefore, be used regarding too long or too strong applica- tions. \ on Franque reports the effect of radium upon an advanced pave- ment epithelial carcinoma of the cervix removed the day after the last treatment. The epithelium of the uterine glands in the immediate neighborhood of the destroyed malignant focus was unchanged, while the connective tissue seemed to be undergoing active proliferation. In some place- the connective tissue looked like young granulation tissue and contained abundant mult inuclear giant cells, probably engaged in the work of disposing of dead carcinoma cells. 1 This will be seen to be ;> favorable interpretation of the effect regarded as unfavorable by Ki-enl >rey. In a case of carcinoma of the cervix previously treated by radium and in which a hysterectomy was done later Kisenbrey'-' considered that radium has caused irritation about the edges of tumor and stimulated if- uTowth. RADIUM PUNCTURE FOR CARCINOMA Celluloid needle- coated with radium of various radio-activities may be in-erted into the substance of a tumor, and will cause sloughing of the tissues, -d that the tumor may be extruded < n ///HN.-.Y . \ radio- activity of 25,000 requires to be left in place for two or four days and the mass -loiiu'hs out a few days later. Stronger preparations may be used with a correspondingly -holler exposure. Cancer cell- are more sus- ceptible than normal cell- to the influence of radium, which, therefore, mav IK- considered to exert a -pecific action. This, however, doe- not extend much more than ', inch from the radium-coated -urlace. and il -eems doubtful whether treatment by radium is an\ le-- likely to lie ftillowed by recurrence than suruical treatments. A large tumor, for ce, of the breast would have to be punctured in a number of |i rent places, ;md thi- would require a general anesthetic. Two !!.") MIL:, u'old needles of radium or two :'>."> millicuries of emana- ueedles mav be left in a cancer of the tongue for -ix hour-: ed two week- later. lladium is applied to the cervical 1 an exci-ed later:' 1 in-ert- radium needle- into carcinoma of the pro-tale, but left h mi; enoiiiih i" cau>e -loiiuhini:. ( 'arcinoinatous i i' -mailer or disappeared. It i- not -uited to very la rue In \i:i ( 'a ivim 'ina of the 1 ilai 1' ler vieli led ill t he RADIUM 12,7 same way, and one had, at the time of the report, remained cured for ten months, as judged by cystoscopic examination. THERAPEUTIC USE OF NORMAL SALINE SOLUTION EXPOSED FOR TWO WEEKS TO THE RADIATION FROM RADIUM A ease in which t he aut hor employed this solution was that of a young woman who was seen in consultation with Dr. H. ^Y. Hall. She was suffering from pyemia resulting from an abortion. There were alce--e- about the hip and other large joints and a very high temperature. The treatment recommended consisted in cureting the uterus and admini tering an ounce of the radiated normal saline solution by hypodermic injection in the back. An immediate fall of temperature took place, and from that moment the patient began to improve, and though one or two more abscesses developed, there were not of a serious character and the patient was soon entirely well. The case is not regarded as demonstrat- ing a therapeutic effect from the solution, but it may have been of bene- fit in connection with the surgical removal of the source of infection. RADIUM IN EYE DISEASES Colin and others have found radium the best means of treating trachoma, conjunctivitis, and catarrhal folliculit is. A glass tube con- taining radium, or a small metal ball on the surface of which radium is varnished, may be rubbed over the affected mucous membrane for a few minute.-. K. .lacoby 1 has treated S cases of trachoma and '.] of follicular con- junctivitis with radium. Several series of four to eight application- of fifteen minutes each were made with 2 mg. of radium in a glass tube. lie does not report as good results as those obtained from surgical treatment and ehemic applications, but it is to be noted that his technic differs from that which is employed by the numerous, other ophthal- mologists, who report almost a specific action. Vernal Catarrh Treated by Radium. Tin 1 author has employed two different technics. In or.e the upper eyelid is everted, an eye-shield i page 1140) protects tiie eyeball, and the radium tube covered by thinnest rubber tissue is applied directly to the plaques of granulation tissue. The glass lube contains 20 mg. of radium salt of 2.000.000 activity and the usual duration of application i- thirty or thirty-five minutes. Another technic dispen-e- with the eyeball shield. The radium tube is in an aluminum treatment tube, and that ha- a single wrapping of thin .r-ray metal, over which there is double coaled adhe-ive plaster. The latter serves partly as a filter and partly as a means of keeping the radium in contact with the right part of the upper eyelid. ] or 3 inch from the free border. The application lasts an hour. The oculists who have sent the-e cases to the author report a cure following several treatment- at intervals of several months. RADIUM IN UTERINE FIBROIDS I ferine fibroids have been treated by curetage; removal of polypi; insertion tor three hours of ill Hi to -~>IH> millicurie- of radium emanation covered with a rubber col on the end of a sound. Kxternal application, in-lead, may be one or more liram- -uitably filtered over various ab- dominal point- tor several hours. Immediate re-ult- are nau-ea for about one day. abdominal tenderness for -everal day-, occasional leukorrhea f< >r several weeks. - : Dclll-rh. M,.,l. \\urh.. Jail. 1 1. HMIti. 2 II. A. Kelly, Virdnia Medical Monthly. April. lOlv 1278 MKD1CAL KLKCTHICITY AND ROXTGEX RAYS I. ('. Feinbery; 1 reports a case of degenerating uterine fibroid that showed tendency to malignancy: red cells 2, .")()(),()()(), hemoglobin 30, treated weekly with radium soft rays; in six months the red cells were 5.000, 000, hemoglobin SO, and the' weight increased from 102 to 140 pounds. RADIUM IN NERVOUS DISEASES Helms shows that exposure to radium tends to bring about a return of seii-ation in the anesthetic areas, in loeomotor ataxia. Zimmern and Raymond call attention to the relief of the lightning pains in the same disease. Abbe reports a case of exophthalmic goiter reduced in size by making a punctured wound in the thyroid gland and introducing a glass tube containing 0.10 gm. of a radio-activity of 300.000. Darier has cured a case of supra-orbital anesthesia from a wound by two applications of radium. There is a beneficial effect upon para- lytic and painful conditions of the nerves, and also upon certain nervous states which accompany convulsions or epileptiform attacks. A case of tic douloureux which was treated unsuccessfully by applications of radium and of the .r-ray, and which recurred after a resection of the inferior dental nerve, was treated by the author with encouraging re.-ults. The .r-ray was applied to prevent the regeneration 01 the excised portion of nerve. Capriati reports th< j cure of a case of facial neuralgia by applications of radium. TONIC EFFECT UPON THE HEART This has been observed by Tonta (Congress of Radiology, Milan. 1900). Ionic Radium Treatment. Radium is carried into the tissues by ,MI electric current , regardless of t he blood-current, quite deeply, and may remain fixed in the muscle or bone sufficiently to have a therapeutic effect. 5 Hadium ion- passed through the tissues by electrolysis produced no effect- appreciable ,-ix or eight weeks after the last ioni/ation." Radio-active waters are carried into the tissues by the constant current .' SUBSTITUTES FOR RADIUM I "rani un i and t horium are not successful subst ii utes for radium even in larger quantities, to correspond with their weaker radio-activity. Mesothorium is an extremely valuable substitute for radium. It '.'.;:- discovered bv Ilahn as a transformation product of thorium, and i- .. :>. I'M I not at all in the state of purity attained by radium. The thorium now in u-e iherapeutically consists O f ;i large amount of iii' :' matter, about 2"> per cent, of radium, and less than 1 per cent. icerl am. but it is calculated t hat jrv, vnl, \\\vi. No. :;, M.Mvh. 1'Jls, RADIUM 1279 is 300 times as active as pure 1 radium and that it loses ">() per cent, in five and a half years, while radium takes 1900 years to undergo an equal The mesothorium in use costs about two-thirds as much as a pure radium salt and requires a somewhat larger dose. Tested with an electroscope it shows an equal amount of gamma rays and can he dis- tinguished from radium by the method on page 1245. In actual treat- ment it is found to be more active superficially and somewhat less active through a great thickness of tissue. Kronig and (Jauss have made extensive use of it in the treatment of uterine cancer and fibroma. In both these conditions it has been ap- plied inside the uterus combined with the re-ray directed through the abdominal wall, the perineum, and the back, to secure a cross-fire. Their success has been almost invariable in fibromyomata and has been good in cancer in an early and operable stage. At this stage the radia- tion treatment, preceding an operation to obliterate the lymphatic and blood-channels, offers the best chance for a permanent cure. The ex- tensively disseminated inoperable cases are materially helped, but a permanent cure is seldom to be expected. One requires for this work from 20 to 80 mg. of mesothorium in a glass tube, with a filter of aluminum and lead or gold and an outer covering of rubber or cotton, to arrest secondary rays. NDEX AnnoMKx, fluoroscopy of, 1017 radiography of, M !. 1017 Abdominal neurasthenia, elec- tricity for, 525 Abnormal electric react ions, 300 Absce-s, dental, in carcinoma of breast, !M2 hepatic, radiography of, 1021 high-frequency current .for. 030 of lung. i>lcurai effusion and, differentiation, 1010 thickening and, diifer- entiation, 1010 pyopneumothorax and, dif- ' fcrentiation, lOO'.l radiography of, lOO'J of tooth, radiography of, 942, !)43, !U4 retropharyngeal, radiography of, !>'.>:. Accessory electrode in .r-ray tubes, '700 Accidents, death from electro- medical apparatus, 302 electric, author's experiments on, 303 manner of occurrence, 350 prevention, 35s from electric-lighting cur- rents, 377 from live \\ires, 377 from telephones, :JOO Accumulators, '.t'.i. See also X!iirn>75, N~l> for plate.-, ssH, ss}, SSS for prints, ss:i, S,s4 protecting metal from, 213 wood from, 213 radicle of voltaic cell, s;-; solutions and skin, currents from, 2ii;i Acid-]iroof insulating cement, 28'.l Acids, fatty, decomposition by Acn. . diathermy for, 03s 1 elect ro!\ -i- in, I Is high-frequency c'urrent for, (121, 1)2."), 1172 radium rays in. 1 270 ro-acea, ca'aphoresis with er<_" in in, ! is static elcctri'-ity for, (27 x-ray in, 1 172 Acromcgalv, radiography in, 1 1< n; Actinium, pure, effective ema- n:it ion from, 12.">2 ray-, 121 t Actiii 'ter, I 1 ,.-).". B_eru. line's. 1 I."i7 Acti' m, current- iif, 27:i in plant-, 2M) local, 2M piis-aue throui;h trans- Adams' thermome_tric measure- ment of .r-ra\ ,711 Additiotial outlet, tapping line lor, 2l:{ Adenitis, chronic suppurative, iodin ana|>lior"sis for, 400 tubercular, jr-ray in, 1 ls<> Adhesion^ of trench foot, static wave currents lor, 71 Adnexa, suppuration of, livdro- electric -it,--baths for, H7 Adrenalin cataphoresjs, 4(r2 Ai'-roferric type of maunet, 11:1 After-fluctuation, positive, 2s:i Aire, anatomic, determined by Air, absorption of beta ravs bv, 12 !2 of .r-rays by, li'.Kj as conductoi 'of electricity, 25 as dielectric for condenser, 24") atmo.-iiheric nitrates from, means of obtainitiK, "iS compressed, for drvins? static machine, 10 compr-es-ion of, analogous to electricity. 52 constant discharge from stir- fa f earth to, 51 contact of metals in, elec- tricity from, !>7 effects of static discharge on, 57 hot, moisture in static ma- chin- and. to insulation. 22-'i ioni/.ation of, by .r-ray, ti-to conductivity and. ill 1 therapeutic use-, litii near earth, radio-active ema- nation from, 1252 normal ionixation over earth, 54 regulator for r-ray tubes, V-;t; Albuminoid- in stomach, radi- ography of, 102s Alcohol injections for trigeminal neuralgia, 505 nervous C'onductibility and, :i 12 Alcoholic facial palsy, 471 Al''oholi.-m, epithelioma and, 1211) Alexander's plastic radiographs, SS.~) Alkaline demarcation current, colloids and, 273 Allan! and ( 'aiiv\ '- treatment of locomotor ataxia, 515 Alloys, fusing points of. 20'.' Alopecia, taradic current for, 127 hii;h-frei|iieiic_v current for, radium rav- in. 1270 static bath- tor, 127 xinc cat-iplioresis for. 10s Alpha-radium rax-. 12-12 pr< idui'I ion of irimma rays by. 1212 -imilat to .-anal rays, 1212 Alteration negativity, -igniti- Alternating currents, accidents -.vith, :i77 charginu' from, KKi death from, :)", : j i72, :i?:j d'vnamo, power of, i:',2 effective value of, Hi2 effects on heart, :i7:-i electromagnetic interrupter for, s.->7 for high-freara- tus for, t'.U maximum value of, 102 muscular contraction with, 3 15 100-cycle, 101 110-volt, 213 oscillatory current and, difference, 552 oscilloscope connected with, 70s path'. 'Ionic effects. 3t')5. 372 physioloL'ic effects. 2',U. 2'.'5 rate of flow of. 101 rectifier- for, 723 respiratorv paralv.-is from, 372 secondary, high-frei|Ueiicy j--ra\- tube for, 734 sell-induction to make con- tinuous, 140 shock from, 3(iO, 307 tlierai>c",:tii- Use of, I''i2 to test conductivity of liquid-. Is2 transformers, 102 for .r-ray work. Ititi-lGO sei'oniiary current in. Ill 1 Villaril interrupter for. v~>ti electric-light current, char- acter of, 101 Aluminum cassettes :us plate holders, sltj cell, mo eli'ctrolytic rectifier, 723 in ( 'alih'-ell interrupter, >54 cup of x-ray tubes, ti'.l'.t filter in j-ray treatment of skin disease.-, 1171 in rnnstruction of stati 1 ' ma- chine, 3!l screen, secondary ra\ - from, nu to protect from r-r:!\' b';rn~. 7'. 's voltage required for. 0'.'7 Alveolar absc(>s- cause of tub'-r- culosis, :'53 localization of, !>45 1281 Amak'am, !u-ib',e, 2011 V ik iiiiMtiini .'I' /inc fur vol- taic cell, VI Amaurosis, h.\ stenc. -is:; Aiiu'iu irrin a, mercur\ . vap, >r li-ht baths tor, lis'.l' Ammeters, 11>1. See also. 1m- Ammonia, synthetic manufac- turr, of, .")S Amperage, I'.' different kinds of, -HI factors intluenrum, ."ill, 51 [i >r dire, : elect rotherapeutic applications. 201, 205 measurement, !'.' of bio-electric currents, 271 of hinh-frequency current, mcasunni:, 7.'!s if secondary current, 7o5 of voltaic cell, si, v,-, relation to physiologic effects, 2i<5, :;ot Ampere, -in, Kill, 172 theory of mairnetisni, 11-1 Amperemeter, 1!M d' \rsonval, 110, l'.i:{ foi .r-ray work, s.",o -hunt circuit with, 20:1 . \inyi nitrite, etTect on reflex r-ardiac st i:uiilation, :',,',> Amyotrophic lateral sclerosis, bulliar paraly.-is in, 47.") elect ricity for, 51 1 . \nachlorhydria, radiograph v in, Hi: ;n -tatic electricity in, 7.") Anaphoresis, -toil ' iodin, ton Anatomi'- as_'e determined by radio], (ry, 11211 An: lotm, radiography in, Ill's Anclectrics, HI Aneiectro'omis, 2S2 excitability and, 2S-1 -"vtiL'th of, L's:', A: inia, faradic current for, I 1! in leukemia from .r-ray, ll'O.'i mercury vapor liirht bath- pernieiou-., diphtheria anti- Toxin in, 1 lux ./-r:i- in. 1 I'.is Ane-the-ia. blue-lipht, list; trii-, r.L'.S See aKo Rltr- Ir,, .,,',, ,,. faradic current for, 17O i .i irreiil for, ,-i2!) local, iron, interrupted ual- \-auic current-, .",:i(l ii -ina pec. or,-. ;,:jO lor bronchial a-thnia, :,:',0 Anfriokeratosis, elect rolysis in, 1 is Ant;ioina eavernosa, elect rol- \.-i- for, -till Aiijtlf, sine oi, lno, llll tangent of, 11MI Animals, development of, I.ixluc current and, till r-tat ic elert rieity and, 7 1 elTei-ts of hij-'h-l'recmency cur- rents on, "i7:( of radium on, 12(10 flcetrie currents in, L'(i7, 2liS cause, L'Mi measurement, 174 si^e of, death from condenser discharire and, o7 1 tissues of. effects of electricity on, 21K) electrolysis of, 21)7. See also 'El,, -troli/sis of ani- ittnl tixxurx. vital processi's of, static elec- tricit\ and, ."i-l Anions, 21s, 2.":i discharge of, 2r,9 formation of, 2">!l Ankle, radiography of, 1071) .-prained, static wave curn>nt for, 7-1 Ank\ losis, chlorin cataphorcsis 'tor, 1(1.") of lower ,ia\v, radiograpliy of, 1K17 Anodal closure contraction, H31 dilTusion, 2">H, 2(7 ojieninn contraction, .'i.Sl Anode, 2l,s application in nerve-blocking for neuralL'ia, .'{S") of electrolytic cell, phenom- ena at, 2."ill transmission of current from, 25!) x-ray tubes for radiography, 7(10 heavy, 7(10, 7(11 Antagonistic muscles, stimula- tion of, :-', IS reaction, .H!)7 Anterior cornua of spinal cord, (ranjrlion-cells ot, source of elect ricity, 21 VS i rural paralv sis, 171 poliomyelitis, I'eekham's method in, obi superior spine of ilium, mus- cular fracture of, radiog- raphy, 1071 Anteroposterior radiography, cardiovascular topog- raphy in, 1002 of chest, 1001- KM).'! of ethmoid cells, H7O, US."), !i si; of frontal sinus, '.'70 of maxillary sinus, 1170 of neck, HVI ot -pherK.id cells, ;isf, (,! thirh, 1072 Anthrax, galvanic current for, 12s Anticathoile for heavy currents, 7iK i nl < .inliilni tube, 77(1 of j--r:i.\ tube, li'i'.i, 7OO, 7 ."ill \\ ithout, 772 Ant 1-1 pt ics, elTect ol, 2(17 Antitoxin of -arc,, ma, 12:i2 \: . . , nyema of, i:nlioir- Antrum, radiography of, '.I'M, !i.">l, !i."i2, Utis.'liM for comparison, Hs:5 stereoscopic, 1IS7 Anus, fissure ot, hij/h-frequency current for, (112 Aorta, aneuivsm of, radiog- raphy ol,' 1(H)1, 100(1 Huoroscopy of, KIO.'i radiotrr:i])hv of, 1001, lOO.'i, 100(1 Aortic atheroma. triphase baths in. I IS Aperiodic interrupter, 112, 72S Apex of luiifrs, tuberculosis of, 101 1 Aphasia, electricitx 1 for, ,"i!7 Aphonia, hysteric,' 17.">, ts:{ Apical forame:!, dental radioj;- raphy to locate, ll-lll Apostoli's bipolar vaginal elec- trode, :s, Tungsten electrode, (1(11) lights, bath, physiologic ef- tects, (IS.") Ho)iue, (iliCi, (itiS Kinsen, tit)."), titiC) I-'in.-en-Heyn, (1(1(1, (1(17 1'itTard, (Kill rays from, reflection of, '(iliti, (KiS tests of, (loS thera]>etitic, 6(55 uses, liSS voltaic cells as power, 205 production of, 2()(i rectifier, mercury, H):i Arcet's metal, fusing point of, 2( 11 1 Arcinn at swiK'h, prevention, 135 in primary coil for .r-ray work, 7:U Arm, arteries of, injected, radiograph of, 1 121! Armatures, 12o of electromagnets, 1 12 Anester. licht ninj;, 220 elect rol\ tic, 227 Arrhenius' theory of electric- it; , S2 Ar-emate to seiisibili/e tissues to licht. tis2 Arsenic, radium-bearing, 12(1(1 Artefacts ii]ion film, si 1 Arterial h.\ perteii- ion, diath- ei m\ in, (10(1 electric st imiilat ion for, liili lion for, .").",:; hi>.'h-tre,|uency ciirrent in, inducto-i-e-onator etlluve for, 7ii stal ic electricity in, 7 1 ii\ pole tisii in, lii^li-tre(|llelicy current in, .",27 stat ic elect riritj in, 7 1 ten-ion, low, static electricity I.NDKX Arteriosclerosis, high-frequency Autopondensation, application, current fur, 575, (.(Hi .").").''> triphase baths in, t Is i-oueli, .Mr,, .",4(1 Arthritic diathesis, migraine of, for arteriosclerosis, o'Od salie\ lie cataphoresis fur, tll'.i for calculi, .".Mi Arthritis, blcnnorrhagic, ga!- for diabetes, ">!I7 v:iiiic current tor, I-' t tor I)npu\tren's contrac- chronic, bipolar d'. \rsonval tion, .V.7 current static inducto-res- for gout, tiO."> (inator for, 75 for neurasthenia with hy- detonnans, .r-ray in, lli'O pertension, ."..sit sinusoidal current^ for, t 1 I for obesity, I.O.'i diathermy for, (i:i7 for pulmonary tuberculo- gonorrhea!, of knee, iodin sis, DOS anaphoresis for, 107 for rheumatism, .".(I!) radiography of, Ills diathermal currents for, (iill' livpert rophic, radiography in. for Kaynaud's disease, f,8:i '1117 for sciatica, .".it.") radium in, 1270 effects of, ;,17 rheumatoid, clilorin ionto- Xacelschmidt's, f,'M phoresis in, -II 1 l.ad, irArsonval current by, faradic current for, 421. .".77 radiography in, 1 1 Iti, 1117 for hypertension, 577 sacrococcvpeal, salic\lic cata- Autoconduct ion by double Guil- plioresis for, 40'.l leminot spirals, .">.".:{ aphoresis for, lO'.t by (iiiillemuiot s spirals in arterial hypertension, ")">i syphilitic, radiography in, age, /H7 111.', 111:} aiiplication \iy, 'i-'t'.'i tabetic, of knee, ioditi ana- contraindications, .">77 phorcsis for, 407 Doumer's results with, in tubercular galvanic current measured electromag- for, danger of, 4L'(i netic field, .">7S uriea, sinusoidal currents for, for arteriosclerosis, (>()."., tiilti -141 for calculi. .".Mi .r-ray for, (>:H for diabetes, ,">7it, ")!)7 Articular front, radiography in, for Dupuytren's contrac- 1 1 Hi tion, ,")!I7 rheumatism, radiography in, for pout, (!()" lilt) for hypertension, .">7(., 577 Articulations of lower jaw, for neurasthenia with h\'- radiography of, i>li.">, 'M'.ti pertension, 5SS A-cendinir aorta, aneurysni of, for obesity, (>():{ radiography of, 100(i for paralysis, 5'JO Asphyxia in electrocution. 5.'i(> couch, 545 Astatic inairnctie needle, )7.'i effects ,,f, .",17 Asthma, electricity for. 4M4 from d' Vrsonval's large so- high-frequency current for, lenoid, .-,.",:{ .")7."). tiO7 lighting by, 517 interrupted galvanic current measurement of high-fre- as local anesthetic in. 5:) quency current in, 5 17 Atheroma, aortic, triphase therapeiric effect of diather- baths in, 4tS mic current in, ti.'i t Atlas, dislocation of, radiog- Auto-intoxication in arterio- raphy in, ii'.u sclerosis, tint) Atmospheric air, nitrates from, static wave current for. 75 means of obtaining, 5S Automatic rhythmic rheotome, < learing from static discharge, 4 VI 50 timers for .r-ray exposure-. moisture, difficulties of ,r-ra\ SOU work in tropics due to, MM Avopadro's law. 255 Atom, constitution of, till! Axial current of rest in muscle, number of electrons in, (112 272 Thomson's theory of, 1112 in nerves, 272 Atonic constipation, electricity for, Cil dyspepsia, electricity in, IM1 H \iu\sKi ret!. A. 177 int errupter, 142, 72S IVtch 'intl \M (r e! Schmidt's I'tmti for, ilii'.i li'.MI static ele 'tricit\ in, 7:> for skin diseases, (i'.K) Atrophv. chronic, electricity Ma.'k-ur. and milliamperi's in a for, :,1 t Ccicilidpe tube u it progressive muscular, bul- changed li'ament in- bar paralysis in, 17."> i-an.li -ci nee, relation be- hemilinirual, 17:, tween, Mil muscular, four-cell bath for. in a gas-filled tube with un- 1 1:> chamred vacuum, rela- T ion bet \\ I -e! Stil current for, til s Hacteri.-i.lal effects of liigh- of uterus. ,-terility from. fre-iueney sparks, 5ti!t, electricity for. !.;:; 571 1 progressive mu-eular, elec- of radium. 125^ trii it\ for, 51 ! il j-ra\ . 1 150 Attractive fnrce of magnets, Rak> r paper di-k static ma- 1 12 chine. :;7. :is Audit -;. n :.-- lire, ISO -tat: n ine for j-ray pn>- nerve, react i< >n > M , Iti'.t din tii.n, 715 I'aldness from r-ray, 1 1.' '.."., 1 K'.H 1'andage for immobih/.at ion, ID! 1 5 Hang's iron electrode lamps, (it'.7, l.lj.s, liliit Hario vacuum j-ruy tube. 71; t Harium meal for ga.-t ro-intes- tinal r:nliograph.\-, KW.". platinocyanid, M).l Sab(,uraud and N'oire pas- lilies of, radium meas- urement by, 121s screen for measuring j--rav do-age, 1155 sulphate and fermillac meal for radiography 102:', in stomach radiography, 1021 Hath, arc-light, physiologic ef- fects, (is:, blue-light, CS7 cabinet, electric, temperature in, i.s5 elect ric-liirht, (i.'.il, (i(i(). See also Elirtric.-liijlit Imtli. l-'ranklinic, f.O h\ (Iro-electric, combined with electric-light bath for obes- ity, liss mercury vapor, (iss radium, 12til. static, liO in obesity, 7'.', ultraviolet ray, physiologic effects, tisl' Math-tub divided by dia- phragm, 1^7 for hydro-electric bath, -IHC, Hattcries, storage-, ill). See also Xt treatment of intercostal neu- ralgia. 507 of obesity, 12s of triu'eniinal neuralgia, 51 1 1 Herleiiiout's x-ray tube uith ai-cessory electn.de. 7titi Heta-raduim rays, 1241, 122 and gamma rays, compari- son between absorbabil- ii., of, 125:; absorption by air, 1242 effect on plants, 12ti() measurement of velocity of, 1212 oriu'in of, 12 i:i production of secondary gam tua rav- by, 1254 Mi-anodal .r-ray tubes, 75'.' Mi-electropraphs, ti'.'s Miehromate cells, uiiper, radiogr:inh\' of. '.I.-12 unerupted, radiograpln INDEX Hi: ocal tube for radiographs', Touse\ 's, 770 Bilateral facial pa!.-y. -171 Biliary calculi, penetrability of, ' 105,1 radiography (if, 101s, UUO Be 'k's techim, IOHI cast's, 1020, 1002 po-ition , ,f patient, lOl'.i technic, UUs value, 1020 Bilinkin's teolimc for cataphore- si- in t:-tula in ano, IH7 Binding-p"-ts of secondary coil, 1 17 trie currents, 20s amperage of, _'7 I nieasureineiit of, L'7."i registering, 322 source of. 2sn Tchiriev's conclusi ms, 2'.'0 voltage of, _'7! Bip"'.ar bath 1:1 s'-iatica, 5os i'leetri<' stimulation, law of, 32s I ir galvanopuncturc, 3s3 ... 3s2, 3 s3 faradic roller electrode, US.') i in zai . ni fi i': incipient cancer of breast, Kit n - mator, ( I'Farrel and Lebailly's, 551 i hidin, 55o, 503 spiral,, 00.-, static inducto-resonutor et- : iv, Mr low blood- pressure, ,(i tor paralyzed and atn>- phied muscles frolll war injurie~, 70 Birthmarks. See .V, Bi-muth emulsion, ;i'.i 1 for stomach radiography, 1021 '. 1022 Bi-.-.rie'- electrode for prosta- uti.-. 5s7 Bi-ulpha'e of i|iiinin, x-ray .vitl , 1235 Black it Hi oxid in radiograjlhy ich, 1022 Black, ninir of .r-ras tubf.-, ^ in liladder, foreign' bodie- in, ,f, lOot, lii.lt hitrh-: : eiiuency appliear i-m- .' , .-:- of, hitrh-fre- rri-nl for, osl : - lor, lo_' , r ,., lt . Jxj rtlu ti-, B :tt- irr-m : ir, 1J1 ' , 'in i-!,., 'trod, (Hi . IJ10 . . ; 1 - irretit . in, Blood-cell.-, Xenist's method of mea-unn^ electric resistance of, :I7 Blood-pressure condenser, dis- charges and, :>7_' d'Arsonval current and, 57-1 digitalis and, o7,") hinh, electricity for, tiO.'i Jii^h-frei|iiency ciiiTent and, 573, ,">71 in neurasthenia, .">!'- in sinusoidal hydro-electric baths, 1!.\ 440 low, in tropi'-s, ti7ti low-tension currents and, 2'.4 Blood-vi-ssels of nose, dilated, electrolysis for, 11!) thoracic. radionra])hy of, 10O3. loo.'i Blotches on j.lates, XII Blower, l.'l Blue Hcht anesthesia, tisti baths, Ii.x7 penetrating power of, tj>_' treatment, i'i^7 Kaiser's method, tiv7 with heat, tis7 Blurring from ditTu~eil radia- tion, M'3 in radiograph'.", diaphr.'it'ii.- for, M-'l, M'o Board compressor, Tousey's, in radiographs' of urinary cal- culi, KM'.i Bobliin, filling, to certain re- sistance, L'L'O Body as electrolyte, !'.> ilensit\- of part:- of, M7 eleetlicity of, Jti.S insulation of, I'M resistance of, IMS, :i77, .'iMi ar-a of electrode.- and, :i^7 electrolysis and, 301 I'.ogue's arc lamp, t'liiti. (ids Bones, changes in, after castra- tion. 1107 diseases of radiographs- in, 1 10.1 gumma of, radiography in. 1 1 10 hs pi-rtrophied, turbinated, ioni/ation for. 107 necrosis of, radiography in, 1 HI; syphilis of, in animals, ra- diogi;iphy in, 1111 radiographs- in, 1 1 10 tuberculosis of, radiography in, 1120 s-r:\\ in, 1 is; i tumors of, radic igraphs' in, I 1 i ).> Bo - r, loo B' >r3 tumors of, electricity in, ol.S radiography in, dot Brass bru.-h electrode, 43 point electrode, 43 Break current, production of, 134 shock, effects, 374 .-witch tor-direct current, 135 Break-finder, 211 pole detector as, 211 Breaking of current, contrac- tions at, 331 Breast, cancer of, cataphoresis for, 403 dental abscess in, '.'42 figuration for, 5(13 high-trec|U( ncs current in, 1 224 inoperable, j--ra\ in, 1223 prognosis, 1227 radium in, 1272, 1274 dosage, 12C,.i recurrent, .r-ras- in, 1222 x-ray in, 1 Kit),' 1222, 1221 teclmic, 1221 Breeze current, application, GO- OD static, direct, (is indirect, iii, (is overhead. 07. !','! Bn-itunp's telephone for test- ing hearing, 1 si i Bremer's formulas for ojitic reaction, 4(is Brickner's tube-stand, S17 Bromid negative jirints, ss.", of radium, 123'.! jiaper.-. SO'l. ssl jirints directly from jiatient, ss5 of hand, lO'.U Bronchi, calcareous, radiog- raphs of, lOO'.t radiograjihy of, 1OO2 Bronchial asthma, local electric t ri 'ill lies, I'hvonic, .-tat ic wav> currents s\ ith ozone in- halation.- for, 77 Broiichiectasis, radiograjihs- in. I I I 1 .1 Broiii'hiti.-, galvanic current lor, 131 hig'n-.'reqiiency current lor. Bronz.ing from j--ray, 1 131 and >harp s\ ire gauges, .Ms Bn, i. stains on j)late-, so] B: u.-h, collect ing, i it stat ic ma- chine. 32 disc), arge, fox-tail, Is oj static electricity, 57. 5S pencil, tor herpe- zoster, 73 electrode.-, 3S3, :;sl bra--. 13 Brushes, 121 Bucca! root-, radiographs-, (do Buck;.- cellular screen for arrest- ing -econdarv ras's from ti. -lie-, S3! diaphragm, s_vi I.XDKX 1285 Bullet in lir:iin, ladiugraphy in, '.mi probe, telephonic, 17K Kunscri cell, '.'1 Hum- troni conduclin^-curd, .1.11) from electricity -'"'>__ in electrotherapy, :;T.s prevent ion, Mss Kontnen-ray, 11 t.'. See nix. in radioL'faphv of stomach and in- test ine-, i .">.") radioirraphic expos- ures with, 7.1.1 therapeutic do>e from, 7.1:; table of voltajres, 710 tran-fornier, Salionraiid do.-e with, 7"> 7 Cadmium standard cell, li:> in Mat ic machine. Mil oxalate calculi, penetrability lit', Hi.">ii Calcium-tiiiiL'-tate -creen, s()/i urinarx , radi> ^rrapli > of, 1 1 1 is. -. . -ical, radii ijirapli; of, 10.1(1, I i ii ; 1 . : I . 7-'(l, 7^ with :iluminu:n 'ci.!l,~s.-) t ul uterus, cataphoroi.- for, 401 me-otlioriiuii for, 1^7'J .:'-l:r. in, i-'-lU radium in, 1J71 ))iinctuve for, !_', (i of, 17.' . :: " :-i;niiL r , -'! t it-, _' ! 1 1 raph\ of, III)! irode, 177 MTl'lHe'ele'ct rode', 177, 17S . 17:; Canal ra v- .-imilar to alpha rays, 1 _' ! J ( ' lie, |jo i- ; : bone, radioi;f:ip|,\ in, 1 I In Canc.-r cau.-rd \>. .,--ra\ , 7n7. I i 17 troly-i.in. 1 1 _' - trie.'./--] iind in, H.TL' iritiary, n ' -for, < ; ( , iii lit, ul breast, btpolai < int ract ion, :;iu :. 17 1 '-. 17 1. 17.'. Mom'ach, L'l I-' lirapliy of, lull.' topom'apii.\ in anteropoMr- rior railio(rrapli.\ , 10(12 Cane-, fluoroM-opy in, '.Us C'arnotiti-, production of ra- lion, K)."i in srlerodactylia, 10") in sclerosis, Uto cocam, m phaL'edenic chancre, ! Ill cocaini/ation by, 10."> copper, for jaw tiMiila.-, K)."i for infected punctun-il wound.- with fistulas, l()t> electrodes f..r. with lui;h- fre,| leu ;, i-urn ::'-. 11 1 experiment.- in. Ion fixat p 'ii ' 'I ion- after, ion . pi cia, ins for ank\ losi>, in:, liim: I i.-sues, 1(1.1 lor cunci'i- di brea-t, (o:; nj neck of Uterus, 101 nf ut i i.-, lot for catarrh of I!i;Machian for I )upu;. t ren's cont ract ii in, ! i i.l ia, Io7 ; :i-tu ; about jau , lil.l . )o7 : ' . - -. I Is wit'n . rt'oti:; inacne rosac-ea, 1 Is la !., . 107 in 1 unetri- ti-, ins -. : : f artliril I! -1-, III'.) 12SI) INDEX : lee, IMS I'm .-emit , toil for u art-, pit. . : trout, IDs mai_'ne- , tor 1 ' 'A arts. Ill : nc litiu w:irt>, IMI; im-ri'uric-, J.V.i, !()_' Ma--. \ '- te'-hmr, i"-' li-tini-tioii, loj iiiniii, ' :' 111! ' li hen ruber, 11s h'-;. \\' . fill ..!_" tiip ni .- for :.. i:i.:il >::,. Hl-.t ti rini . !"J |' . .-.- - 'in i , ;DJ :. 11 1 v.ii - - r, ID) zin . i'H :iinipi-c-ia, His i u:i, 11)7 handle, :!M in brani-hial neurit i>, .",11); traii.-tonniT. |ii:{ voltaic ci II for, .MI, ss f'anvy aii'l Allanl's t rcati of loi'oniotor ataxia, ."' 1 ~> C< 11-baths, pHJvanic, !:; : ii in uriti.~, ! \~> in loroiiiotor ataxia, I K5 >inu>oiea.-e, KHi") IIOMIinl, KID') arterie.- oi. injeeted, radi- ou'raph of, \\-2-l l,loo(!-ve~'.- !.- 01, ra-Hoj-'raphy of, KHI:;, HID.", ej ithelioma of, jc-ruy i:,. U2.3, I _'_'7 in pulmonary ti.bere-iloM-, ID! 1 radiosrraphy of, '.Hid anteropoVterior, IDD1 uith (date in front, !DO_', KID:', expo-iin for, slij for liini.'.-, lllll). See also not in -afittal pl'u . KID:; c.l ii.n:e, MHKi, ID"! top '-raphir value-, IDiil witli p'ate 1" liind, Kinl is. 1, HUM in front, Kinl. H)0'> topography in and rc.posto- rior r-idioi.'raph\-, KHil CI ri.l of i idiiiin, l-'.''.!l ... -: 1-1 I . !C', '' ' ol /!'!' brJoT.' r-ra\ i', epi- th, Itonia, I.-K) Up, ,,! loi ,-l , |D| IN* I) EX 1287 Chloroform .-vncope, faradic Clav electrodes, :',Sl Colitis, r-ray lor, C, 1 1 current for, 12!) C'leveite, 7C.."i Collecting brush ot static ma- Chlnro-i.-, merciir-- vapor light Clip, film, Tousey's, !K7 fracture of, ratliography of, Combined pand%>es, 17s .r-ray in, 1 17!> ! 0117 Comedones, electrolysis for, 11s Ciliary ho.lv. foreign body in. Coefficient of dissociation, 2.if> Commutator, Ms, 121 radiograoliy in, '.'Id of i-\t inet ion. o.s;l interrupter tor r-ray work. Cine;; atttgrapliy of stomach, Coil, ehokf, i:;7 727 author opposed to, 1 0: for .r-ray coil, i:<7, i:!s Compass, III"./., SIHI Circuit-breaker, 121, 20s, 217 separate, m Compound-wound d.'/namo, 125 automatic. 21li cutting lines of force, genera- Cnmiires-ed air for dr\ ing u.-cd in automatic ut-ofT, 217 t ion of electric currents in, static machine, Id Circuits, capacity of, 2 1'i 122 gas in ( iaitt'e's trail-form--:-, conduct ivitv of, law of, 1 ss faradie. l:;i, 1 HI. See also 71 t derived. 1st;. ls7 /'.;.'<;./.- mil. Compression band. 105d, 105! division into de'ived circuits. galvanometer, d'Arsonvai'.-. and inflatable bag in renal IMi p|.i radiography, 1051 insulation, resistance of, movable, angle of deflec- ir 1 radiography of hip- n ' e a - 1; r i 1 1 < ' . 212 tion of. in:; jnint , 1 diis one -imp!'.- and two derived, insulating varni-'nes for, in renal radiography, 1O5O Iso. ] ss 212 cylinder and iHaphraL'tn. 7. -5 principal. 1 s7 heater, platinum, 2iil in radiogr:>piiy ot urina.'y law of, Iss' heuting ot, by current, 222 high-frequency, 5C.5 Schf'inberg's.in radiography short , 2dl fl'irtion niii. diaphragm, 7 P.5 fire from. 20C, length of wire for, 220 Inofah -;,"!:-' with, 7!ld shunt, Is, , 21 1:; primarv. See I'rinuir.'/ roil. Sch.inl.erg-.-, in radi-'g- in electrotherapeutics, 20:i resistance of, 2.'-!2 raphv. S21 starting from battery, ISS t ot -d i mpedcnce in ] }d determining, 221 P.dntgen-rav. See /,'<',/'/<,-' ,,- o; air, analogous to electric- undivided, not forming de- reac'tion of, :i:i2 rived circuit, !ss H/,1 mkorff, 115 ( '"!,--, -ntra'ion i-eil, Horuttll l's Circular elect n,!\ sis, Xewman's, secondary, 1 15. S<-c:iUoX.<- obsi rvations, 2s,; for e-oph;ige:il stric- iii'lnr'/ mil. example , if, 2s,; ture, 121 self-imluction, l.'il Concentrator, 1 1 for urethral strii'ture, 12d Tes a, 511, 542 Condensation of steam by mi!-. 22-! t"sting cat.acitv of, 2:iii, 2-'), sta' ic discharge, 5'i Circ::lai ion, effects of stati total weight of, 221 Condenser, 1 (s. 2M5 i lect ; icity on, 72 varnish for, 212 air as dielectric- for, 215 influence o|, oti ner\-ous ex- haustion, .Sl.'i .r-ray, 151. 'See al-o 1,,,','i ;, ,- paratu.-, 1H7 in neiir-ist h"tiia, ."i22 r // mil. capacit \ of. 2M5 in neu'-omuscultir prcpara- Coin in esophagus, removal. !i!>2. ! a , 215 tioi . maintenance , if, :i 1 ' '. i'. i:! testinn 1 lirect di Cir.-ula'orv disorders, static ( 'oin-catcher, '.ml -.; , electricity in, 7! C. Id ere;,,,, for r-ra\ keratos, -. by Thomsnirs method. diathermy for, ii.15 1144 2:iii effect of stimulation of cer- current- produced i''. ap- char_ r im.'. 2 Id vical sympathetic, I! IX :U!' ]i icat ion t a m rve. :',2s formula' : ' <:'. 2 ! 1 Cirrh i.-i- of liver, hyper'rophi -. diagramn iti.- - piese! 1 stal ic --A avc i urrcnt for , .'< '.] ; 210 Cl:ipp-I-'.:i-t!iai i coil, ..--ray from. la:;!0- tni 1 c\ sti ,sci ipje woi is, disi'luirges, applieation, i' 1 -" 7 12 r,.-,s at hiirh poti'inial from Clark'.- magneto-electric gen- miisc'ilar contraction and, -tat ic machine, :-!ii'.' i Is :; ! 1 .1, a;h - mi. :iti'', :;::;. :;7! i - - . int. -; ittenr. In - s i /< oi inn a n.i , :, 7 1 in of :;.'.- , drn-fara.lic bath for, 111', Cole'- irrai ; nt ' i t rae- i, m in. :'! 1 Claii-iu.- 1 theor.\ of electroly.-is, ;: i ' igraphv . In.;'. effects of, .Sd7 2."io , ,1,... r. v: n ,, ,,,, , ,,, ..,.,-, ,ndarv modification of, -',\ 1 Cla\ic! , -- n ture ;. !lu..ro.~ ; t ~ on bl 1. :;i2 p\ in. HN.i ! . cur- on 1.1 ;-:-, -.-- - . ,-. radingrapln ..!, KI-.IN ,r. '.Id on heart, :;72 radiography of, 1002. KM):;, membranous i'!ectricit\ for, elecrroth, ; ip, ir , Id: is i;-;i of pa'h' iiogic eii'e, ..;. ; INDEX ! faction, :!!) .c. :i7 lii ill ir.ii: . M1O lion b\ . Is.', Hi rvi-, MO! I ' :'. ' - \ - ironi. ' ill 1 . 1 ' . mi pnmarv current induct ion-coil, 'L'4:; i-!i ' ': t'.ou into and nut of. Jlii Ic-. :;s4. ('IN r'k,' :,<;:<,. .vii, ;,t\:, ' . :',s'.i ' ork,' '2: J ,\> ation, 1 Is i excite .-"-ray tube, [it, r-. s.-,7 oil, 7M1 . I '.I.', ,Ti,-, tit.'. i : . l . ' - Is! r n lit.-, of i..i,i/,.,l air, c,l I tcasc>, f, t:i of liquid, cli'finitioii, ls() t:iHcfs for t. -tin<.'. Is ( tclcphoin- i\f tot, 1st, Is.-, t.-tiiiL'. INJ. l.sil vessels for. Is:-; \\ lieat>tone bridjie tor, I.N.') ot iin-tal wires, _'l!) of solids, _':i:i oj urine, iMi dt water, 1'L's tlii'ory of elc-rtrotoiiiH, L's.~, Conductors, I'.',, _<:;:;. lii'.i c:ip;icit.\ of, tr>iin<_' liy rin.iiisonV metliod, L'Hli copper wire as. Hi! I !. c-ondiu tion throuirli, Conn,.: ' litrlit, (is:; il ::.. U77 - iroh -I- i: ; . 1 l!i COIIIM ction-, I 1 ..',, till ' . -, - - - tor, -MO ' I live ti.~ne, dil/ -tion of, iL-raph; and, III:"' li n'ial d.\ namo, \'2~> li| at ii in, atonic, elect ricity i, ;.:] habilual. ell ctrieitv fof. I-M for, i:;:; radio;-::, pi.-. ,,[, llljs H, 7:; rreni for, '-,,. ,, dvanieeur- rreni for, i;0.- from intermittent current li.\- >elf-induction. MO patliolojiic efTeds, :f7_', ::7:{ C'ontraction. fihrillar.v, in elec- trocut ion. .-).':] . ."iUli from >! iinulal ion, '27 ~t, '27 (\, ipncity and, :-! H f '(intrust in,' IDL'l ( 'out n-iniiiilin interrupter, "L'.s [.(due modification, 14 t radioplioiometric metliod of 1 I.-.C. Cnntu-ion>, galvanic lairrctit for, lL'(i static breeze for, 7'.', C'onveciion, charjre b\', L'l C'onvectiye discliari.'('-, L'-t. (. See also Mfitt'r n;,,, ntrnnt. f'onverter, rotar\', 1-'!1 ( 'onvul>ions, epilept ifonn, from cort ical -timulation, o.'i!! Coolidne lube, Ki'.l, 77t and tran-tormer for dental radioirraphy, \i:$7 anticathode, 77ti div-tnirtion of, throuj-'h fihunem current, 7so for dental radiography, 7s_> j/roimdin^, 7s_' inrandi scenee, 77ii n.anipiilai ion of, with in- duction coil or Malic machine, 7s.~> with Tousey's yvncrator ol con-tant hi^'h-ien- >ion current or ith transformer and hiL'li- tcn-ion rectifier, 7.sl motor L'i -in rat 01 and ; rans- fonner for, 7,s) pioductioii of ./'-rax in, 702 il ion nt, _7_77 sell'-rei ' if \ iiiL', 77 ~> .-p:irL-L'a]i ami >pintre- mctcr \\ ill,. 77'.l T. iii-'\ V -\;L"-' >1 ion lor', 777 \ aeiiu'm, 77 about ' 11. tor, i::i -. , ; ind \ oltamete,-, iM'.l I, ind re- -i.-tance of, i.'JJ nice ol. _']'.! , '"., f'on-d conductor, conduction L'h. L's.-,, L'NIi ( INDEX 1 2M) 1001 in pulmonary tuberculosis, 101 1 radiography of, 1001 Cotton insulation for .r- ray con- ducting cords, 7:i7 Couch, aiitorondrnsation, ."it.") autoconduet ion, 5 1,", for high-frequency treatment, 515, .vi t; indurated fiber, 540 Couirh, galvanic current to pro- voki-, 4li4 , C'oxin, S71 Cracks in tilin from develop- ment SOO Current of action, local, 2X1 passage through trans- former, 271! in muscle during tonic contraction, H27 in ureter, H27 of rest, 270 produced by cold applied to a nerve, H2S by stimulation of nerve without change in col- loid appearance, IW 1 strength of, average, 72li testing for, 210 triple phase, 12.X unit of, 171 Cuspids, lower, radiography of, llli") upper, radiography of, OH2 Cutaneous area.-, ^pinal-cord segments and, 170 te-ting, L'li! I, 270 nerves, 170 tenderness, areas of, .".01 Cut-off, automatic, circuit breaker used in, 217 Cut-outs, L'OS. C.\anid process of obtaining nitrates, 5 IS Cycle of alternating current, Kil Cyst, hydatid. x-ray in. 11S."> in bone, radiography of, 1 lOfi sebaceous, electrolysis in, 4 1!) tooth, radiography of, !*4~), Hlf, Cy-tin calculi, radiography of, '1057 Cystitis, high-frequency cur- 'rent for, . r >Mi C'ystoscope, Brown's, ()">7 ('\-stoseop\-, protargol as pro- ph.\lactic alter, lOtiO D\MI'I.;I> oscillations, .">3!) Daniell cell, !M DanneV varnish for radium application. 12til> Dark-room, .sJO liu'ht for, ,s70 mercury vapor liirht for, \7() \\"e!sba'ch li'irht for, s7O u indow.- of, ^70 d'Arson\-fl current, indirect., effects, .".71 ozone inhalation^ \\itli, f>."i with t -lass vacuum elec- tro. le, effects, o7 I , .".72 ilnpolarizablo electrode, 271 large solenoid, .",11 autoeonduction from, small solenoid, 510 application of current from, 55:; transformer for abscess, oHO for cellulitis, ():',() for chorea, 5112 for constipation, OH) for epithelioma, 021 for gout, 005 for high-frequency current, 544 for lumbago, 5(15 for neuralgia, 5!)I5 for neurasthenia with hy- pertetiMon, 500 for painful flat-foot, 500 for periostitis, 020 for rectal diseases, 014 for rheumatism, 000 for sciatic neuritis, 505 muscular contractions with, 570 with .-mall solenoid, 500 voltmeter, 107 Daylight plates for radiography, M ),s Dead-beat niilliamperenieter, 1 1 1. 'o:i Deafness, electri-'ity for, A'.'A phonoirraph for, ]x() tele]. hone in treatment, 1x0 voltaic \-ert iiro as test, H05 \"ates method of t roatinir, 4.'-i5 Dean's ,r-ray tube. 702 Death after .r-ray treatment of exophthalmic iroiter, 1 l! Do la Hue'- voltai.- cell, '<;; Delherm's contraction ;t ppur:i- tu-. 1x7 sialvanic meth(.d for troii'.r- rheal rheumatism. 125 D. lirium r-ordis in ele tl -.ion. 51-n. :,:!(-, : , L'xx . ,,, n, ,1,1- : U ,,l. .'7:-; I ):-: iij rill n lit, _'l'l .- ' .. .;i>-> .,l li, ii.1, ixu 1 Dental : ' -',-- in cardni ,ma ' ' I'n [-, method ,,I calculation, or,o. !u;i w ',, ; :.ii:i; i if. I), in I'n ial :': nf, '.'til ,:tt;. p:.. :, - -. Id.") . devdnpint! dip- fur, n:;x ,; vcli ipnn-nt : . in ,_".:... Dental radioirrapln. keratosis j Dpsmoid tost, Schwartz's, 1030 nt tini_',T- frnin, '.rj, | Deprez electric .-innal tor tim- mc-i-un-meni- in, 'i.V.i in m.\ otrraph, :; Is, :il!t. ol'l). of antrum, '.'.">(), '.(.11, '.!.">_', :iL'l '.Mix Dc.-truction of :-;0-milltampere of ;ipic:d foramen, '.U'J radiator Conlidne tube of bicuspid-, unerupted, : through overheating, "So Dr-tector. ]inle. extemporized, Develop,-!-, X7.S il canine teeth, unerupted, , choir-t- of, x7s. x.x'.l '''>'> containing no hydrochinon, if flariiiL' foramina, !'IM XXL' if toramina, '.14 :.', '-'i:i eikon .f inferior canal, '.nit. 'JG."> for forced development, xxx maxilla, '.'O.~i for screen plates, x()x nerve, '.Mi t Ka.-.-abian. x'.M) M. Q., ssl inetol hydroquinonc, ^ ortol, S.S'L> pyro, x7> pyrocatcchin, vs -_' fhrolkeld-Edward.s SOS It vdopn.i lit It ir, ''.,'' r>',- '. . ['ini.-i - '-. '.'-'n. '.'.'1 - "i>y, '.'^2 in id .; , '.'17 ."._:.':_ flunn i.-i't ipf ill, '.'_". '. :::.' ' } til : , ' -: ,.::.^-. Hl'.i -.,:' nintr ni rrt tii. '.'17 IC'll. '_'! iiir-ri.pl It, tli, '.Us I-'.:.! .' -i-tci-ttjl fill I,, .n -.-. int of lower teeth, '<:,'! of nerve, '.I.V_' interior, '.nil m pulp. <<:,_> ol pulp-r-tone, \>:>2 n; root-canal, '.M'.i Developing clip- lor dental ol roots nt crowned tooth, factor, lL>. x7x '.'-VJ powder>, Ka-tman r-ray, xx_> temporary tooth. '.)~>'.i tank, paragon stone, xx] n; unerupted teeth, (i.Vi tray fol dental film.-, ::'.'.> lower, '.Itili, '.KIT Deve'lopinji-out pajn-i>. xx ( mea.-iiremr-nt by, H. r i."i De\-elnpm,-nt. blotche, on of i.pi'er teeth, '.<-'.-', plat,.-, x'.i] nn horizontal film. '.'_'! in film. x;i() pap, -i fol prim.-, xii'.i. '. 1 1:-; defed., in. xxi;, x'.M) pcr-pectivc in, '.'.)>, '."'.:. '.If 11 ex) ilana t ion, x ( . m pi im . examination, !H 1 exposure to ruby liL'ht. x71 -ter,-i-copii'. '.Mil fadiiiL- ni imaL-c, xx7 storage nt ]ilate>, x'.i:] film uadied nlT duriiiL', x!)0, . "__'. !W) x'i] \enii-al film-carrier in, . in nverexposure, xxx !'L'7 in ' rojiii-al r-rjiintrie>, x'Mi ei : diascope, 771, 772 influence of .r-ray duriny, -XM! ol dental film.,, jii'-' a.- ' la !./' : -,..-:.: .-, '.<'.V> I . '-'_' : - etli d, ''liH 1 )( tit i-t. techiiic tor, in dental brom iti papt r lor. xii'.i -- ., ,] . . o:;x ' . ' . 7xJ I i - : . - , ' ['.In, iiirht thcrapx- and r raii-int mer lor, u itli h'-at in, 'ix7 !:iT D, p i / r, olid, double-fluid !, "22. 1 ! Hi eel!.- uith, ','1 i tor, xjj l)epo,it- ii lube.-, MO i.c . x'.i:; J), ,,; i irar-tnre oi -kull, rc-tnrim.-. xxx : . - : . . n, nil ratlioirraphj in, '.'I'-' '.Mil .-andy depo,it.- in, ,x! '.!! I), n-um'- di-c;,-,., ./.|a\ in. Derived I t,, |xli, Ixx . 'tjl ivn, and on, -imple, ]xii. . '.'27 Ixx '.-;i '.'17 !). -. 7'.'1 - - : i t, !<.,_' Den iiiti'- from fluoro,t -, 1J.V7 |ii!litii, elect -tain,- on plate.- rlurinir, x'.il tank. x7'.i xx] I'm films, XMI n nla lor, xxu py, tt ni'-, -7:; ti-mpel .'. I, S'.lO t line Ic. ,1111, -d. xxil. xx] tadu iphv ot, I ), . ation- m na.-al -,-,,1.111., | I ect , .,1 b\ n m of, teeth, '.)(;_' i., dm .;.'.' . -. Mint, I ), \Vattcville current. Set . ii 1 _' I )e\t r,ir-al i , Ii\, ]>n-il inn oi ... . . . , i, Hi rr.-nt thn :-!.. Hix oi km -I.,! t'h-!r, IU.TI 1 Ii ib, I, -, a itnconrluetion ' < i at i, n.aehint . d'.V r-onval ctu rent for, ",7'.' 1 ), |\ - : ent of, 7.', i i. I t,--t hich-frei|iienc\ current for, : il currents for, I !_' INDEX 1201 Diahcte~, static electricity in, 71, 7.') .r-ra\ for, ,"i7'.t, o!l7 Dialietic L'an! lead. 7! niovi'iiii-nti ot, 10(11 of .r-ra\ metal, 7'U <.I,...tro, 'i:-;7 for arterial hype: tension. i()i; for ai thi'i'i.-, ii:;7 tor i-h iiv:i niim n , i;:;> for rlir.iiiii- pro-ia! i(i>, [i:{7 fi ir i-irc-,ilatoi'\ di~< inlrrs, ii:-!."i tor di>i :i-i- i if uoiiicn, i'.'-17 fi ir i-piliirinii. '-> s i. it L'onorrhi-a. ti:;7 fm irut\ .1. p..r-it>, ill).", .... . ,;.;s r] d-. li i-i n , hnir of. IM'.I for impot.Ti.', . '.':, 100 Diflcctrir, .",'.! air a-, L'l.'i li.|iiid.- ionixcd hy ultra- violet ray.-, t')7C, hy .r-niy.-s V,ns riL'idit\ . _'l:; ' rapliy, ^2L' DifTusion, anodal, LN7 cxtr;t])olar 'i;r:cnl~ of, dire tion, _'^_' Dijre-tive disorders, diathcni for, <;:-;r, rurrent. hreak -wit.-h chariiiiiK from, lo_', !0:i "i(H)-vo!t, L'l I for electrol herapeut ie,-. L' 1 ", hiirh ])otentia! for j-ra\ , 7">0 motor generator for x-ray work, 7r.o |()()-Volt, L'O.'i disdmnre to tesl capacitx of condi'ii-ers, -Mil Statie lllee/e. Ii7, IIS Disehartre, . Huh n>i r. See ' ', - l)i ' in, n. .liatl 1 ) in iitinti nt atlas, radiot:- . . ,.,.- 11. Y.I ai-t inometer to measure 11.-)- liariuin plat inoe\-anid sereen for ini-asurina, 1 loo Hi r Castex's method of m. ;i>- uriiii.'. 1 1 ->7 lire, 1 I." t C'ontremoiilin'- rnetJuxl o; measuring, 1 l.'r, furehod's methorl of niens- urinu. 1 l.',7 electroseope to mi ni:;, ii.is erytheniti, at various radio- irra]>hi'- strengths. 1 li'i'J in onlinary therap .' strensrth] lHi_' l-'rank!iu'> elect roscoj>e to measure, 11. '>s (iaifTe's method of n . :is- interruptions in primary current and. 1 I HI .1 . .... . .,.,... nririL', 1 I.V) Kii-nlmek'- i|uatititoineter to mea.-ure. ! i:,s I.iira, hi', mi tliod , 111.', -.:.:.!. 1 lot qiiantitomcti r to tii' ilsli! . ! l. r i> ra.l ipl loini'tric 11 tl 1 ineasiirinn. 1 lot; Sa!. onrau. 1 and No i method ol : , 1 l.-,x. MM Sehuart/'- n.,-t! INDEX phy of, I >: IL'S, :: - ular ci i!:traet ions Dry",', : tes tor radii ,irr:iph\ . MIX iond unpolarizable . !,- trod.-, 1274 - i] -tiinuiation, 31l2, 334. EAR diseases, electricity for, 43 1 elect roiliat'iio-is in, 3'.!.") h'.L'li-lreijUeticy current for. lilil impeding circulation of, cf-re- bral rataphoresis and, 101 middle, diseases of, combined d'Arsonval and (Midin methods for, 43."i l-!arth, constant di-char<_'e from surface to air. ."> 1 as storehouse of electricity, internal structure of, railio- activity and, 11213 in irn.al ii mizat i' 'ii ' :' air over, '' /:.' rent for, t'.L'ii n nl . ."17 medical ; real ment. r,L'7 i . 1 1 i i' 1 1 - KHiow. normal. 10(10 radiography of, 10SS exposure' for, Ml' tuberculosis of, radiojrraphy in. Ill's Electric accidents, manner of occurrence, .'{."ill of i)revention. :i."s Tou.-cy's experiments on, olio anesthesia, local. .-,:;() apparatus, Mor-e'- .-iirL'imr, -139 arc. production of. 1'llii capacity, inrasurinp, I'.'il unit of. Ill charge, normal, of earth's surface. .->4_ carried hy rain. ~>\ conductivity of cows' milk, 397 of human saliva, 397 of liquid.-, 1^1) of solids, 1'33 currents, attraction between, cai-ryiiiL' )iro!)erties of, l'."i7 detection of, lli'.i di\-idin.!i of. IM! from niajrnetir-ni. llii ficncration in coil utuim line.- of force. !_'_' heat produetii.n b\ , 1'iil" in animal, 17 1. i'ti7. 1'ti.S in plants, 17!. i'i!7, I'llx induction of d\ namic elec- tricitj by, i' :',!' mea.-ureiiient of, Hi!) of -kin. I'li'.l rcL-uIation of, L'Ol ^-treiiL'th of, 139 unit of, l!l death, .")30. See also El.r- triiriiti'tiH. dial\ sis, frclatin delnineralized douche for torj>or recti, -t3L>, 433 for chronic constipation, inte-tiiial dou. -he-, -|:;L> litrht, r,;,j acci.lent- from, 377 and telephones, accidents bath, I ','..9 i '.(I! Hi-../, iit-.j c-abinet, r,f,n, f,r,l temperaturi' in, lis/i c.nnbined uith hydro- . I. . trie bath lor obi - it\ , I'lS-, I ol lUL'il : i ...-..: '.-. i,ss tor arieriosdi'i-osis, lidii INDEX ttiiecmc iignt natn, ponarjie, tit'lL', 001 IMeciricitv lor amvoiropnic lateral sclerosis, .'ill jLjjeeineiiy 101 pseuuoiaoes, .11-1 recumbent, (Hi], 002 for aphasia, .">17 for renal pain, .IK) bulbs, nitrogen-filled, 0.1s for atrophv, .11 i for sciatic neuralgia. .101 conjunctivitis from, OS3 for Bell's palsv, 172, 373 for sciatica, .107, .10s current, alternating, char- torbrachial neuralgia, 501, 500 for sclerosis, amyotrophic. acter of, Itil neuritis, .100 .11 1 POS1 III', Mi for brain diseases, 510 for -pinal diseases, 51 1 for radiography, 71 1 tor bulbar paralysis, 475, 470, for s-. ringom\ elia, .11 .1 heat production of, Mi, s7 .11 1 lor tabes dor'salis, .11 1 induction-coil operated for cerebral growths, .~>1X for test icle neuralgia. 11 1 bv, tor x-rav work, 71!) for cervicobrachial neuralgia, for torticollis, .11!) lamps* 210 50(i for trigeniinal neuralgia, .101, service, 207 for chorea, .11'.) .101 sockets, -M<> for eoccygeal neuralgia, 501 for wry neck, .11!) tests of, fi.">7 for cranial paralvsis, 170 forms of. Is measurements, 111!) for diffuse spinal disease, 515 frictional. Is, 1!). See also motor, 120 for diseases of central ner- Slnhr rlrctririty. power service, 207 vous system, l.V>, .11 1 from ganglion-cells of ante- unit of, 171, 172 of eve-, '130 rior eornua of s]iinal cord, reactions, abnormal, .'5(11 of motor ganglia, 51 1, 51 1 20 S normal, 3sO of pyramidal tract. .~>1 t generating, means of. Is resi-tance. 10!) of sensory patlis, 51 1 harmful effects, 3.11 of blood-cells, Xcrnst's for cnterocolitis, 131, 433 heat production by, 202 method of measuring, for epilepsy, 51s history. Is 397 for exophthalmic goiter, 520 in animals, 171, 207, 20s of lymph, 3!)7 for facial neuralgia, "j()l in eye. 20s response of nerve, delay to paral\"-is, 172 in nature, .1 1 second stimulus, 343 for fourth-nerve paralysis, in plant-. 171, 207. 20s sleep, 4!)3, .12s 171 in radio-active substances, current for, 12S for habit spasm, .~>l!i 1211 I.educ's, 4!)3, 528 for hemipleii-ia ."> 1 "i!7 in radium, 1211 sparks, nature of, 27 for herpes iTciiruliria, "nil, :,0l ionic theory, 1!) stimulation of olfactory cen- for high blood-pressure. 00.', life and, 207, 2(is ter:- of brain, 3.13 tor hvpoLrlossal paralysis, 17") local action of, 303 of optie nerve, no sensation for hysteria. ">21 Lodge's theory of transmis- of light in, 3.13 for infantile cerebral paral- sion through gases. 01(1 ten.-ion, liydraulie pressure vsis, r>17 magnetism and. relation, 107 and, comparison, 7S, 7!) sjiinal p:iralysis, "il 1 manifestations of, Is tetanus, 330 for insanity. .">22 mechanical equivalent, 123 production, 337 for intercostal neuralgia, .107 medical, detinition. 17 subniaxhnal, of striated for intraspinal disease. ">l"i negative. Is. ](i. i>.-,;i muscle, 337 for lateral sclerosis, .11 1 non-conductors. 2.1 thermostat, Kegaud's, 203 for locomotor ataxia. .11.1 one-fluid theory, 1! units, 4s for lumbago, .110 passage through body, 300 C. C. S. system, 170 for mental disorders. .122 through conductor, 2.1 variations in heart, 27S for mult ip'e sclerosis, .11 1 through Crooks' tube, 040 vibrator for massage, ()02 for musciilocutaneous neu- through gases, phenomena welding, Mi ralgia. .101 of. 12 Electricity, air as conductor, 2.3 for myelitis, .11.1 through non-conductor. 21 animal, cause, 2Mi for nerve injuries. 1.11 through solids. 201 burns from, 2! Mi for neuralgia, .10 1 through vacuum. 04.1. ii.11 bv elcetromagnetic induc- for neurasthenia. .123. See pa-Mtig through patient, cal- tion. Kill also \,'tira*th,-iiin. culating. 1 H coagulation from, 31)0 for neuritis, .10 1, .103 pathologic effects on blood. compression of air, analogous for occupation neuroses, .11! I 3i i to, ."> 2 for ocular paralysis, 171 on power-house workers. conductors of, I'.I, 2.1 for organic diseases of central 3OO cooling efTects of, 2til nervous system, .11 1 physiologic efforts of. 21)2 death from. See /.: ' (- for ovarian neuralgia, 101 densitv of current and. (inn. for paralysis, 1.1.1 302 detinition. 17 combined, 17s on vertebrates, 2!'3 discharge of, 17 Krb's, 177 position of electrode- ilynamic, 78. See aNo !)>/- hysteric, Is3 and. 303 ntunii- tlu-tririfi/. infant ile, .111. .117 relat ion of amperage t. >, earth as storehouse for, 21, musculospiral, 17!'. IM) 2! 1.1. 30 t 221 obstetric, 17!" of voltage to, 2!'.1. efTects of, 17 of anterior crural nerve, 1M 31 1 1 harmful. 3.1 t ill deltoid, !7s positive. I'l. 210 on animal t issues, 2! Hi of iiura~]iinatus. ! , s quantitv of, unit of, 4!' on blood. 300 ol median ner\ e. IM) resinous, I'.i on elands, 302 of obturator nerve, 1^1 resi-tancc to pas-age of, unit on heariiiL'. 302, 303 of plantar nerves, 1^2 of, is on heart, 2O3 of p. ipliteal nerves, l^i static. Is. 2.1. See also Slut on microorganisms, 2!)2 i if scial ic nerve, l v 1 < I. r-tririt't. on muscle, 3O2 . il serratus itiagnus, 17s theories of, I'.i on nerve-fibers, 3O1 ol sixth nerve. 171 through straight wire, mag- on respirat \- >n, _"' 1 i>f es. 302 of third nerve. 171 transportation of matter b\ . on tactile sense, 3O2, 303 of trape/, iid, 177 21)!) on taste, 3O2 of vaiius, 171 two-fluid theory. 1'.' electron theorv of. 213 peroneal, 1M units of, 171 . 1 1 2 faradic, is. See also /' for paraplegia. .11.1 : . ( i . | ,1,,-trint;,. for poliomyelitis, .111 voltaic, 'is.' See also i for abdominal neurasthenia, : u progressive muscular ./.-:, -, 52o atrophy, .11 i Electrics, I'J i'J'tl I.NDKX :- trilied body, attraction of, Electrodes, carbon, 43, 3x2 Electrodes, shovel, for hydro- for other bodies, 2t> cla\ . 3s[ electric bath. -13x of pi'h-bal! by, 20 condenser, 3x1, ll'X size for bipolar application, :i:L-ing other bodies, with, for high-frequency current . (13") I'l ~>l 13 ->i 1 1 "ill "i .-kin and, difference 'ii poten- loss . : . harge of. 23 for surface applications, tial between. 31HI I lect roca rdii 'gram ' H ' 1 3' ' ". 3xO ti30 -park indirect d7 [ration of heart operation ,,f, .MKI -pong,.. 43 -'Hind-. .;_'7 at distance from pat lent , and in.-ulated handle, 3X1 in ai terii isclen i-i-. 3 I'll .-,1)1 spray, li'.l in cardiac neuroses, 3_'ll cords tor, -13 static, 13 in cardiovascular diagnosis. detector, extemporized, 212 Tousev s. o.VI _". '1 exploring, Tousev's, -I.V.I exploring, 4. V.I 1 :.:il trouble of auri- external. 3s(l tor fulguration, 'illl', .">(13 cle-. 327 faradization by rolling, 3S.3 indirect sprav, till in hypertrophy of auricles, Ml'ii for cataphorcsis with high- vacuum, ".!.-> < it let t Vent ri'de. 32". frequencv currents. -11 1 i >: i itri. 1 vent nc';e. 3l'."> for cutaneous application. in neurasthenia. 3_'ii 3x0, (130 vaginal, 3x2, 3X3 in organ 1 .'- arti ria! di-ease, 327 Wehin-lt interru])ter in, virtual, 33X cardiac disease. 32il 3.s(l with glass sleeve, .~>s7 in rapid pulse. 327 for diagnosis, 3SI1, -l.'.S wood ball, 43 in vascular thyroid disease, for diathermy, Ii32 hollow. 111) 32ii for electn.diagnosis, Toiiscy's, point, 43 of possible lesion of right 3'. r 2 Klectrodiagnosi-. 3xil limb of Tawara, 327 for electrolysis of animal tis- and physiotherapy in war Pai lion's left lateral decubi- sues, I'mi, 2(>7 injuries, l.'il tus desirable tor, 327 for faradic bru-h, 3X3, 3S4 condensers for, 3(1!) ; ha.-es ' if, 32."i currents, 3x0 discharges for, 3sx showing irregularities of aor- for fulguration. .".Hi', .")(i3 electrodes for, 3xtl, 4.VS tic insufficiency, 327 for galvanic electricity, 3s(), Tousey's, 3H2 of cardiac rhvthm, 327 3S3 in alcoholic peripheral neu- Electrocardiograph/DuhamelV, for galvanopuncture, 3x3 ritis, 31i.") 327 for gums, (117 in ear diseases, 311.") Nicolai and Huth's. 17.1, 32-4 for high-frequency currents, in eye diseases, 3H3 Elect rocliemic cauterization, -133 3,s(), 41 (.s motor reactions in, 1 .">."> equivalents, I'.M, l'.V2 in pyorrhea. (117 neuromuscular reactions in, Elect ro"oagulat ion, (13!) for hypertrichosis, 3s3 45(3 of degeneration, 31'1, 3H2 a-pl.yxia in, .")3li for liiggs' disea.-e, I'd 7 of m\ asthenia. 3'.).") hy alternating current. 372 for skin, 3sli. H30 jirognosis based on. 3117 b\ condenser discharge, 3li'.i, bipolar, 3si>, 3x3 record of examination, 31H1 37n. 372. 37:-> \Vehnelt interrupter in, 3s() Electrodynamic indui-tion, di- b\ ''.ntinuous current, 372, for static electriciu , 43. 3X1 rection of current, 122 37:> for surface application, 3s(). E lect rod vnamomcter, 11(3 t,;. crossed wires, I'll.", i ;:in Siemens', 1K4 b\ high-tension currents. I'll.") for testing conductivity of Electrolysis, IMS bv industrial currents, 3ii'.l liquids. 1x3 bulbous-pointed needles for, b; I .-due current, .V3U. :,:>,\ for urethra, 3X3 411) causes of death, .'.:-; 1 for uterus, 3.s3 burn- in 37x changes in, .'.32 glass, filled with liquid, -I'.HI by voltaic cells, XX, I'.Vl delirium cordi.- in, .".31, ."3i> vacuum. 3s) circular. New man's, 120 diagno-is, .'.30 handle- for, 3xi conductivity and. 31)1 ir\ contra' t ion in, ">31, for galvanopuncture, 3x3 connterelectromot ive ton-e ."i3(> in.-ulated. 3Sl during, 2">() hi - ' in, .">3o interrupt ing, 3s."> current for, strength of, 413 hemorrhage in, .">33, r,3 1 lion-interrupt ing, 3s."> deep, strength of current for, . :;::,, :,3i i Hart'.-, for fulguration. .",1)2 41 t -"'"' hollow wood, use of. (Ill dest met ive, 377 effect on body resistance, 301 ".--, '."31-.-.3I tial at single electrode, Faradax 's law.- of, 2.M -. ;,:{() 17s impolarizable, 27 1 for acne, llx for angiokerat o-is, -IIS p'h\-i .-! death. d' Vrsonval's, 271 t' ir angioma cavenn isa, 1 I il ':,:>, i 1 )u Hois-Heymond, 271 for birth-marks, 117, 117x :....-. : .;. ith, -".-:( lie.-, nault's, 271 tor cancer, 1 1 2 [.ii idet.-imcter, K.-iioist, . n in elect r,,!;, t ic cell, phenomena for comedones, lls 1 .. ; -, . ;-u at . 2.Vi for c.iniunctivitis. vegetative. ' - - >r\ . :n .r-ra\ tubes, 7'iO mt raga.-tric, 3x."> UK .. kaolin, 3x2, (His for cysts, sebaceous. 1111 -:. -... n . 1's.-, lamp, (Hi. i'. II tor dermal it i- papillaris capil- p, ' .:.. '- - . Ill 111 massage roller. 13 litii, 4111 . -. Iain - ol b'.ih materials for, 3x11 for e.-ophageal stricture, 121 mi Millie use.-, 3sn. :;xl lor exophthalmic goiter, .VJO : lie roller, 3s."i ne. die 3s:; for folliculitis vulva-, 120 ; .- ., 3s:; ot voltaic cell. VI tor hairs ne\ i, lls . - . |ilr -ii .: >gii 33s for hyp'ertrichosis, :-',oo. 3S3, . ;s.j platinized, 1X2 113. 311, 11.-. 1 e. v e , for . lei troly.-i-, 2''7 for h\ pertn. ph\ of no-e, llx for ele.-trol.vlic cell. 2. V.I for keloid, 4111 - po-itini : -. I on elect ri/a- .; la'-rimal -i ricture, 121 ! ii'. n. 303 lor lupus er\ thematosiis, -llx : t . t . 1 . 1 ! - '. l.t'i d :-, 170 for I-, mphaiigioma, 1 lo : ' . vi. 3-1 r. . tal, 3xi' for liiacroglossia, 121) : l)oiinn r's, .'.-.-, for nasal deviations, -till el. 177 vacuum, id 1 polypi, 1 111 ...... . 3x3 -purs, !!'< ingn .... ic, :>;, for in vi, 1 lo, 117, 1 17.x INDEX Electrolysis for ozena, 110 for pigmented ncvi, I IS tor p'llypi, n:i.-;il, 410 fur port-wine .-tains, -117, 11\ ! 17.S for sebaceous cysts, -11!) for strictures, esophageal, 121 o! lacrimal duct, 121 of urctlira, 420 for sycosis, 4 IN for tattoo-marks, 418 lor vascular ncvi, -t Hi tumors, -I Iti for vegetative conjunctivitis, 41!) for verrtiga, 41'.) for vulvar diseases, -12(1 for warts, 4 111 Fort's linear, 420, 421 indications for, 410 ionic medication by, 300. mechanism of, 2,1(1 medication by, ionic, .'500. _See also Cataphortsi*. Newman's circular, 420, 421 ot animal tissues, 206 burns from, 208 electrodes for, 20S coagulation necrosis in, 207 polarization in, 200, 301 products of, 207 appearance at, elec- trodes, 200 secondary, 208 uses, 300 of dilated blood-vessels in skin of nose, 410 of pases, 044 of li.iuids. (544 of solids, (144 of water, 218 platinum electrodes for, 297 product.- of, 248, 207 theories of, 2.13 Clausius', 2.13 Grotthuss', 2.13 urethral, high-frequency (air- rent after, .ls(> voltage for, 2.10. 2.11 Electrolyte, s2, 2r>l, 2.13 body as, 2.1s for .r-ray interrupter, 721 ioni/ed 'iias as, (144 ion> in, velocity of, 2(11 jelly. 2(11 outside battery, passage of current through, teniper- ature changes, 2(i."> oxidation of positive ion in, 2.10 pa -.-age of metal ions into, 2.10 passing current through, 2.10 plienomena in, 2.10 precautions in mixing, 0.1 reduction of negative ion in, 2.10 sulphate of copper as, 01 testing for, 2.10 Electrolytic action of x-ray in causing erythema, 1 1 1.1 cell, anode of, plienomena at, cathode of phenomena at, 2.10 connected by asbestos M rands, i_>.">7 countcrelectromotive force of, 2.10 electrodes of, phenomena at, 2.10 Electrolytic interrupters, 1 1.1 for 'x-ray work, 720 mercury, care of, 727 jet ,'721 turbine, 72.1 principle of, 720 rectifiers for, 723 Hopiijuet's, 72.1 Wehnelt, 722, 723 polarity of, 721 lightning arresters, 227 medication in gonorrhea, 407 rectifiers, 10(1, 723 aluminum cell, 723 Elect romagnetic effects of static force. 1 13" factors governing, 1 12 in hollow cylinders, 1 13 in .-olid cylinders, 113 galvanometer, 173 Snooks', SC,0 Weston's, SIH) induction, electricity by, 10(1 in power-house, 21(1 static electricity from, .1.1 interrupter for alternating current, S.I 7 for triphase current, 8.17 vibrating, 141 wheel type, 1 13 system of C. (',. S., 171 waves in universal ether, 115 Electromagnet ism, application of, -1.13. -l.lt effects, 4.14 Electromagnets, aeroferric type, 110 armatures of, 1 12 ferric type, 110, 120 field. 123 for powerful currents, 113 for removing foreign bodies from eye, -154 iron for, 1 13 law of attraction of arma- ture, 113 maximum efficiency, 111 non-ferric type, 110 physiologic' effects, 4.13 poles of, determination, 100 power of, 111 therapeutic effects, 4.13 volume of, during magneti- zation, 1 13 Elect romechanotherapy, 4s3 CailTe's apparatus for, 4s7, 4ss, 4s!) in chronic articular rheuma- tism, 42!) Tousey's apparatus for, Isil Elect roinedical apparatus, death from, actuated by electric-light current, 3112 Electrometer, 717 capillary, 171 LipmannV, 174. 17.1 Einthoven'.s string. 17.1 for measuring voltage of r-ray current. 73s Nicolai and lluth's, 17.1 quadrant, 101 Elect romet ric apparat us. Curie's. 1241 'hart-. 320 measurements, 2sO Electromotive force, 2(1, .10. Electron. 17. Is, 2.13 .r-ray in, 7O2 in metal-, vi locity of, 2(11 theory of elcctri' ity, 2.13 E.Vctropathology, 3.1! Elcctrophorus, 30 charging of, 30 ctn and ionix.ation chamber for mea.-urement of radio-ac- tivit\-, 12'tS current, of /eleny, 1211 for measuring x-ra\ il(j-age, (113, 11.1s PilTard's, 121.1 static, 1211, 12 t.l to test radio-activitv, 12)1 Wulff'.-, 21 Electnjstatic capacits' of gutta- percha, 22.1 testing, 23-1 induction, .11 system of C. (.',. S., 170 voltmeter, 217 for x-ray current, 73s Elect rot herapeutic apparatus, absein'c of pathologic effect.-, 37.1 applications, amperage for, 204, 20.1 voltage for, 204, 20.1 bath-tub. 438 table, Tousey's, 445 uses of heat generated by re- sistance, 2U2 Electrotherapy, burns in, 378 experiments, 378 prevention, 380 condensers for, 300, 40.5 definition, \, dynamo for, 1211 ' machine for, 40.1 examples of faradic, 422 galvanic, 422 sinusoidal, -122 Elect rot onus. 2s2 anesthetics and, 283 conductivity theory of, 28.1 currents of, 282 direction, 2S2 effects of, at various dis- tances, 283 Hermann's theory, 2SH modifications of, 2s3 nerve as cored conductor and, 2 S.I nervous conductibility and, 284 excitability and. 2S.3, 281 physiologic effects of, 2s3 polarization theory, 2stl po-itive after-current of, 28.3 theories of. 2-S.l Elephantiasis, galvanic current for. 127 Elongation of muscle, reflex, 3-17 Emanation, radium, collection of, 11.11 Emanatorium, amount of ra- dium required tor treatment in 12(17 Embryo, effect of x-ray on, 1 1 :-; i , n 33 Empyema of antriim. radiog- raphy of, '.i.ll, o:>2, OtiS, !is_' osi; of ethmoid cells, radiography in, !is( of lung, radiography of, 1013 Emul.-ion of bismuth, ''.MM Knallaxatone current. 4v.l apparatus for. 4VI Endodiascopr, 771 therapeutic u-e, 772 Endoin(>tritis, hemorrhagic, zinc cataph.,r.-i- for. (iis En"> and, 'ill.", 4 .V. 1 to seii-:bilize tissues to light, Krythemat odes, high-frequeney Kxposure, duration of, sll (Is 2 current for, (121 with induction-coil and Epl, Title sellslbl 1 It V, -P.'., -t imulatioii and. Kill Ervt hroc\ tes, effect of r-ra\' on, iin gas-filled t ubc, Sll with transformer, Si 2 Epididvmiti.-, acute, diathermy Erythromelalgia, galvanic cur- holders for films, S10 for, H.S7 rent for, -127 table for Hontgen-rav ther- diathermy for. d/!7 Erythropsia from ultraviolet apy, 1 HIS high-fre. iiieiicy current for, rav, (is:-! radiographic, Tousey's, .->V'! Erythro.-in for sensibili,:ing S90-902 r-ra\ for, ",s:i Epilation, diathermy for, doS tissues to light, (isl Eseuhn with r-ray, l'2'M I-!xtemporizels ,VU Extra ravs 7111 See al-o .s' r- Epileptiform convulsions from 99-! cortical stimulation, .'i.'l'.l foreign bodies in, localization. 1 'x! ra-uterine jiregnaiK'y, radi- Epiphyseal injurv at shoulder, i ji i 1 ' t' r ' '| l IS 'I' 1 1 ographv in. 10(17 radiography "of , 101C, radiography of, with tube Extremities, lower, fluorosoopy line i 'I hand, radiography of, behind, 1004 of, 10(iS 1 11)1 stcno.-is of, elcctricitv for, radiography of, lOHS Epithelioma, alcoholism in, i:U) radiography of, bromid paper 1210 electrolysis for, 121 for, Mill Hat surface forms, 1211 from mediastinal tumor, exposure for, S12 fulguration tor, .">lil, ."ili:-! radiography of, I'll.', UJiper. congenital le.-ions of. tunirating, radium for, 1273 radiography of, !i!i"> radiographv of, lO'.l.'i high-fre<|ueticv current tor, Ether, nervous conductibilit v fluoros.-opy of, 10S(i (121, 1210 and, :i42 fractures of, railioscopy of. of che-t, r-ray in. 122.,. 1227 Ethmoid cells, empyema of, 101 IS of ear. r-ray in. 122.', radiographv in. Msl radiography of, 10SC, of eyelid, r-ray in, 12H1 radiography of, U7(), HM, Svhdnbcrg's compression of face, .r-ray in, 121:,, 122.",, '.IS.',, I'Sli cylinder in, lO'.'l 1 22 1 i if '. >ret,ead and nose, radium a nt i Topo-t erior , .1 1 0, 'SI, for, 4:',d for. 1211 lateral, list, '.IS.', elect rodiannosis in, :ili:5 1 pa'ate. r-ray in. 121.", ]''.u-tachian tube, catarrh of, high-frequency current for, ills of inner canthu-. r-rav in, cataphoresis for, 10.", luminosity test in, :*!)! 1212 Evaporation of water, electric r.ai lium in, 1 2dl of lip. r-ray in, 12Ui charge and, (14."> effect- of lightning-stroke on, ol nipple. r-ra\ in, 12i:i Examination, ultra microscopic ds:i of ii,,.-e, r-rav in. 121 1, 121.", stimulation of nerve-liber of radium on, 12(11 nl orbit, r-ray in. 121'i. 127.", under. :1 of ultraviolet rav on, ds2 nl pan i! I' 1 regii ,n, radium lor. Excitability condenser, .'Jsll of r-ray on, 1 WS 1271 degree of, :;:; i electric current.- in, 2dS of peni-, r-rav in. 1217 tatadic, :jMl lixalion of, for Dixon'- local- i idium in, 1271 galvanic', :{Mi izing method, I'll, '.'i:i irn nee after exci-ion, 1 2O'.i law of, :;i.-, foreign bodies in, localization . idium for, 1271 mii-ciilar, nature of. :i:il of, 111 IS I-', i Hi.',, 120'( ner\'ou-, alter transplanta- radiography of, 1'OS -tic before, 1210 tion. :',lf> muscles, movements of, under ' |,l 1 ',1 /.iliC be),, re, 1210 at different parts, .'ill! corl ical ,-timu at ion, li 10 do-age. 7011 cold and, :;i:; pal-ie- of, 171 ,gic change-, 1210 elect rot on I!.- and. 2s:{, 2M ne|-\ e of read ion of, HIS pic change-, 12lo faradic, Pio radiography of, alter injury lapli re-i for, Io7 anomalies of, Kil fat iL'Ue and. '', \'.\ seei itn larv react ion i ,1 . M'.' 1 . 1 27 1 galvanic, 1.1s. Kil steel part ides in, elect romag- 1 i! lion metho.l ol heal and. '.',W ni 1 ic extract ion of, 1", 1 oltage, 111.-, inlluence of drug- on, :!12 Eyeball, diameter of, !M."i '!,. t hod .,: mca nature of, :{:;! pet fora t ion of, radiography ' Ige pli', t racl ion and. .'! t:i for, Mid Erb - ' ItiJ ol ! cart in lock-jaw, :i.",1 [iroti-d ion of, from r-ray, ; of motor nerve-, variations 1 Kill, 1 1 10 : ' ' in. :;12 Eyelashes, effect of r-ray on, ' ot -pina 1 cord , Mil Wei '- law of, :U.'i Eyelids, cancer of, r-ray for, . . ' 1 ,\' itomolol effect of -tat 1C elee- effect- on eve, 1 l.'i'.l . : i : . Iricit \ . 7:; epithelioma of, r-ra\ in. 1 21d .V_'.-| i .-.. . faradic, Id! I'- -. 17! galvanic, Kil I-' U'l., epithelioma of, r-rav in, 1 , : d -" ' lei ler degree ot, f.Hl 121.!, 122.",. 1227 1 _'.' 1 nervi m-. inlluence of circii- sinu-e- ot, pneumatic, fluo- rrent lor, ' _'d lation on, :{]:; ro-.opy of, '.Hill 12! 7 Face, sinu.-es of. pneumatic, radiographs' of, diagnostic value, '.Mid ' Facial nerve, branches of, test- ing of, 173 le.-ion \\ ithin aqueduct, 473 parah.-is of, 172 alcoholic, 171 bilateral, 171 diptheria, 171 elect ricity in, 172 herpes and. 471 involvement of sixth nerve, 171 lesion within pons, 1 , I otitic, 171 reaction of degeneration in. 473 without taste involve- ment, but loss of hear- ing, (71 stimulation of, for dry otitis media, 131 trunk of, stimulation, 3S.s netiralgia, electricity for, .~>01, high-frequency current for, .V.I3 radiography in, diagnostic value, 907 radium in, 127S ultraviolet ray in, 1193 j-ray in, 1 Id2 paralysis, static wave; current tor, 473 Factor, power, 7.">S Fading of image during devel- opment, s.s7 Fahrenheit and Centigrade Fallopian tubes, < Midin and I )' Ar.-onval combined method for. 43li Farad, Id. 172 Faraday, 2ol, 2.V2 Faraday's laws, 2.'>1 Faradic brush electrode, 3>3, MS 1 coil, 131, 1 Id Helmholtx, l.-),s, I.V.I interrupter for, l.VS interruptions in current, ion nature of current, IfiO ordinary arrangement, 1-Vs, I.V.I j)rimary waves of, 1(10 rapid interruptions in pri- in, Iti'l) source of imperfection in, i.vs with Wanner hammer in- terrupter, I .Vs. I.V.I current and vibration for obesity. tLN electrodes for, 3s() for alopecia, 127 for anemia, I 1 1 for anesthesia. 170 for bulbar paralysis, 170 for chloroform s\ tieope, 12'' for constipation, 13 1 for cutaneous gangrene, 127 for diarrhea. IS.' for dry otitis media, 13 1 for Duchenne-Krb palsy, 179 Faradic current for hemiplegia, 517 for h\ drart hro.-is, 12U for hysteria, .V2 i for hy.-teric aphonia, !7.~> contraetures, 4*3 paraU.-is, 1S3 for ichtiiyosis, 127 for incontinence of urine, for intermittent claildica- tion, 13d for liche,,, (L'7 for lumbago, old for motor disturbances of stomach, (3D for muscular contractions, 11)1) for miisculospiral paralysis, ISO for mya-thenia, 39.') for neurasthenia, ~S2.~> for neuritis, .V.I3 for obesity, 42s for obstetric paralysis, 479 for ocular paralysis, 171 for paralysis, 100 for pemphigus, 127 for perforating ulcer of foot, (27 for poliomyelitis, "ill? for prurigo, 427 for rheumatoid arthritis, 426 for sciatica, .~>07, oOS for secret orv disturbances of stomach, 430 for spasm of external sphincter of urethra, 130 for sternomastoid paral- for stimulation, 33S for stricture of esophagus, 430 for testing branches of facial nerve, 473 malignancy of lump in breast, 101 neuromuseiilar appara- tus, IV.) sensory react ions, 107 for torticollis, old for trape/oid paraly.-i-, 177 for triireminal neuralgia, for urticaria, 127 for \ itiligo, 127 for wr\ neck, ol'.l from lonir seeondan coil with iron core, strenirth of. Id2 galvanic current wit h. See general indications for ef- fec*s of, 121 illilui-ed. 217 Ledue curretH and. coni- pari-on, Id2. Id3 ir contractions h\ modification- in effect-. 107 ime for, automatic, |so stimulation by, 1st therapeutic effects of, 122, 12.; indications for, 122. 423 tn itn cut by, I.Vs L'I oi mi asui 217 ', ctri.-it\ . Is tinit'i ni, Is thi-rapy, < xampli - of, 122 Faradic excitability following de-t ruci ion of motor area of brain, 312 loss of, in oxalic acid poi-- oning, 3 12 exhaustion, nil hyperexcitahility, 39(1, 401 h\ -po-excitabilit v \\ith gal- ' vanic formula, 3dO loss, 40! roller electrode, 3s.'> Faradimete:, _' 1 7 Faradization by rolling elee- Faradogalvanie current for atonic dyspepsia, 131 for entcroeo'it i.-, 131 , 133 for facial paralysis, 472 for hemorrhoids, 012 for lumbar sprain.-, 130 for menorrhagia, 131 for motor disturbances of for neurit i-, ")03 for renal pain, ">] 1 rheotome for automatic, 489 stimulation hy, 4s.~> Tou.-ey's tech'nic, l.SO Fatigue, influence on contrac- tion, 333 negative variation in nerve and, 2SO nervous excitability and, 313 reaction of, 3d2 resistance in muscles, _static electricity showing, 71 static electricity and, 71 Fats in -tomach, radiography Faure's aciaimulator, 102 l-'avus, x-ray in. 1 174 Feet, radiography of, bromid paper for. s()d expo-lire tor. M2 Femur, neck of, fracture of, radiography of, lOOs ununited. radiography in, 1071 Fenwick's phlebolith catheter. 10.VS Fermillac and barium sulphate meal for radiography, 102:', Ferric t\ p- of magnet, 1 Id, 120 Ferrie's ondometer, "il7 Fery's dry cell, do l-'ctii-, effect of .r-ray on, 1 131, 1 133 radiograph of, in utero, 1007 Fibrillary contraction in elec- troeution, .V.il. .V3ii Fibrillation in heart from elec- tricity, 3-V2 l-'ihroids, uterine, radium i'l, 1277, 127s Fibromyoma. uterine, Apo-toii treatment. 133 (iau-.-'s rontgenotherapx for, 12H7 mesothorium for, 1209 radium for, iL'O'.i rontgenothera]\v for, Toii- se\ '- teehnic,' 12(17 Fihrou- coinlitions. high-fn- iMirrent for, ">d7 Fibula, fracture of, Pott's radi- ography of, 107s r:nlioL'raph>- of, 11170, ](i, , radiography of, ll>77 liznets. 123 I d-plates of static m: 31 Fi:t\ -centimeter .:-- INDEX Files, plate, 893 Fleming rectifier for high-frp- Fluoroscopy of heart, 007 Fihi.L' bobbin to certain resist- quencv current, .",30 of humerus, 1080 . -'-'n -tandard cell, 92 of knee, 1072 Film, xi ix Flexible contact diaphragm, 801 of leg, 107.") arti facts on, M 1 Flexions of uterus, high-fre- or lower extremities, lOOx celluloid, inflammability of. quency current for, .">s2 of lungs, 000 810 Flower- of sulphur in tinea cap- of maxillie, 917 clip, Tonsey's, 038 it is. 11x3 of neck, OSS, 001 di nl ,. di v.-liiping clips for. Fluid in sphenoid cells, radi- of pelvis, 1017 !H ;x ographs of. 9x7 of pneumatic sinuses of face, ili \ 1'ipment <.f, judging. Fluorescence, nature of, 0.">3 972 930 ' nl" tube. 709 of pulmonary lymphatics, duplimed. 910 Fluorescent medicines, behavior 10OX, KHIO gla-s mounts for, Totisev's, of, 1230 of radius, 1080, 1090 911 bi-ulphate of quinin, 1 23."i of shoulder. 1080 t ra\ devel, ipment fur. 030 e-culin. 1230 of special parts, xo.-, development of. x7ii. x77 fiuon-cin, 1230 of stomach. 1021 Fastman duplitizod jr-ra\ . for gastrodiaphany, 1230 of thigh. 1071 810 radiance from, 1 230 of ulna, 10x0, 1099 xposiire tiolder for, xl<) slowing effect, 1230 of unempted teeth, 91S, 010 file, xo.; with x-ray, 123.") of upper extremities, 108(5 : '::._- if, x93 Fluoresein, dosage of, 1 137 of ureteral calculi, 10.V1 t> ir 'i' ntal ;n lii igraphy, tank. internallv to sen-ibilize tis- of urinary calculi, 10",4 .levelo,,ment, xx(i sues to liglit, iixl of wrist, '1080 frilling of, X'.ID. x'.il radiance from, 1 137 prolonged, X9."> horizontal, radiography of with x-ray, 123.", room for, 711 teeth on, 021 Fluoroniete'r, Tousey's, 841 stereoscopic, SIS ii -t ml me' ms, M 1 Fluorophototrraphy, 803 technic, 710 nl -, celli: 1. 041 Fluoro.-cope, 709, XIK; to differentiate hematoma glas:-, oil attaehn.i-nt for. , .",0 from fracture of skull, packet-, ductile. 92:i author opposed to u-e of, in 004 tooth, overdeveloped, reduc- gastric diagnosis, 1034 from hernia cerebri, 004 tion of, 9:iO box, 709 to estimate size of heart, 1007 ragi of, x'i:-; in radiographv of foot, 10x0 to test lung reflex, 101.", tank develi pn cut of, xxli in renal radiography, 10.V1 usefulness, x9."> n cr, l' u-tinan, x]ii care of, 709 Flu.-h receptacle, 2O7 I . ; h ' S , '. ' 2 X dangerous, 114.") Flux, magnetic, 11.",, 1 19. See ' ' :'.. 927 dental. Tou.-ey'-, 920, 021 aL-o Mnamtic Jinx. Filter and cellular Mucky screen deterioration of, 709 Focal infection of teeth, 029 : rarrcstinKS-ei '.ndary ray- John-ton. 710 Fogging, x79. SOI . issin -. C'h' lice be- magnifying, Tousev's, 021 chemic. S70 twi :.. x:;l operating, 710 due to envelopes, si t, M.", fi , - , j-ra - 7'ix SalviniV, 922 in -torage from jr-ray, X 93 Toils' . '-. clo.-e to plate tor screen of, color, 7O9 Follicnlitis, radiutri in, 1277 re--ing -ccondary rays illumination of, intensity vulva', electrolysis for, 120 fiuoroscopv Touscy's dental, 920, 921 Food- tuffs passing through of, 111 '2 : gnifving, 921 stomach, radiogr:i]ih\ of, 102x gr i pi :. 1 102 1 luoro.-cop\ . 7MI l-'oot, artel ies of, injected, radi- gl ph of. ! ' 19 1 In fore radiograph\ of frontal ograph of, 112x - - :: p, e.e,:,, tiiii; sinus, 973. 971 fluoro-copv of, K)x(l m lupus. 1 Ix:-; danger or. x9.",. 1 1 10 pertorating ulcer of, high-fre- 1 ins. -!; :. lamp. 017, MX dental, 922. See also Dint'il qtiencx- current for, 029 . iting, 200 ' . , <,-,,,,. radioL-iaph\ of, lllxii - / is. '.I'M ili nn :i tit is from, xo.", tuberculosis ol b. ines of, radi- : . ' ' .", J in brain tumors, 9O1 ographv in, 112x i ol. 1121, 1122 in carie-, olx ulcer oi, perforating, faradir i ' . * , } . - "] _] T-(.( 1 ] |(' J Jl'\ m pneumonia, 1O1 I current for, 127 rn-nt for. ol_> in pregnancy, 1 133 l-'oramen. a],ieal, dental radi- : . bo n ' ,v . copper cat- in p:'lmonar\ tuberculosis, ography to locate, 04s KI.-J 1011 mental, in radiograjihv ol in softi iiing of ti-fth, Olx lower bidi.-pid, 01. "i -7 '' 1 x 01 abdomen, HH7 Force, 170 1 . , , . , . ; . f,,r, of juitrum 9x1 Forearm, arteries of, radiograph 107 ' ol aorta, 100.", of, 1121 of che-t, 090 fluoroscopy of, 10x0 - ... . .. .,.,; normal, 1O90 ... : shoulder, igiaph\ of, loxs, 111x9 1102 |-"on ILTI bod\ in . ilian ! il\ , bow, 10x0 radiography in, OH1 ; current. 211 ol fi 10! . Inxii in cranium, localization, t herapi-ut i'>, - it tori at in, lose, 9(1 1, 9ll."i. 91 Hi . . n e-opha- radiographv lor, 0(11 1 r Dixoi '1. 992, 993 -ti-i eosci ,p]c i adiograph;. . ' ' i ! , ' * 1 J ! .. 991 triangulation in, 9OO i :,-, o n i - ri nt cl;,i ic)e, Kixii in e-ophagu-, localization, ; . . . 1 linger-. 1 102 991. 902 i.l hun.eni-, IOXIJ, 109X, in eye, radiography of, 008 . in inic-tin.s, loi nl, !O2x n g, - '.II' Hii:, ol lit a.' 1099 in neck, radiograpl . '91 . . . ...-,., - - : efore radiog- in orbit, radiograph;, of, ' !( )^ ' , - ''/--- r,f, pHiri 1299 Foreign body in stomach, local- Fracture of scaphoid bone, 1111- Frontal sinus, radiography of. ization, 102S united, radiography of, 1 100 with patient seated. O7.'i radiography to locate, x<>4 of scapula, fluoroscopv in, 1 < )Sd transiliumination of, OS] rornialtn in development, S'K) undiluted, for .r-rav warts. radiography of, 100s 127 1111 of skull, fluoroscopy in, 002 Figuration, odl Formula for "ikonogen-hydro- hematoma of scalp and. electrodes for, 5(12, 5fi:', (|iiitniiic developer, SS2 fluoroscopv to differenti- for cancer of breast, ~>W for hvpo, SSt ate, 004 tor epithelioma, 5(11, 5(i:( tor M. (2. developer. SM hernia cercbri and. fluoros- lor tuberculosis, 5d2 for ortol developer, SS2 co))v to differentiate, 001 for r-ray dermatitis, 5(12 for pyro, S.7S radiographs- in. 002, '.Hit warts, 1111 for pyrocatechin developer, of tarsal hones, radiograph v Hart's electrode for, 502 SS2 of, lOSt, l()s.-, Tousey's electrode for, 5(12, for tank developing, SSO of tibia, 107"), 107(1, 1077 5(i:{ for tropical developers, SOO of tooth, radiography of. 050 Functional angle in pulmonary intensifying, sso of ulna, radiography in, 1000 tuberculosis, 10M Forschhainnier's formula for of wrist, radiography of, 1000, Fungating warts, magnesium sensibilizing tissues to light, 1 100 cataphore-is for, 10(1 (IS 2 united, radiographic appear- l-'uniciilitis, acute, diathermy Fort's linear electrolysis for ' ances after, 1 101 for, (1M7 esophageal stricture. Frame for holding plate in an radiant liglit and heat for, 51(1 420 inclined po.-ition for gastro- Furunculosis, cataphoresis in, for urethral stricture, 420 intestinal radiography-, 10:i!i US Four-cell bath, connections tor, Franklin as unit of density ot galvanic current for, 4^7 444 static charges, 70 high-frequency current for, for muscular atrophy, 44") electroscope for measuring (121, (127 for Ka\ naud's disease, 44.1 x-ray dosage, 1 15S -tatic electricit\- for, 78, 427 for rlieuniat ism, 444 Frank'inic bath, (10 Fu-e wires, 200 Sclmee's, 4 1 1 Freckle.-, red light tor, (1S(1 Fused salts, conduction by, 2(11 sinusoidal, 4 45 Freezing mixture for moisture Fusing-]>oints of alloys, 200 I-'ourth nerve, paralysis of, 471 in static machine, 10 of metals, 200 Fox-tail brush discharge, 4S Freezing-point of solution-, 2'itl, ("Factional volt selector, dental, 2*17 for cataphoresis, 404 Friction spark, (1(1 GAO-XKHK'S plate-holder, S]5 Fracture, callus after, radiog- type of static machine, -im- (laitTe's a[>paratus for using raphy of, 1104 ' pie, 31 alternating current Trans- Colics', radiography of, lOS'.l, Frictional electricity, is, p.*. former for x-ray work, 1(17, 1000, 1000 See also Stutir ilidr^-iti/. Ids Tousov's positions for. resistance, 220 arrangement of ventril tubes, 1090 sourc(>s of static electricity, 55 7ss functional results after, 1104 Friedlander shield as dia- contraction apparatus, 4SS of acetalmlum, radiography phragm. 701 hot-wire galvanometer, SdO of, 1070 water-colored x-ray tube, 7d3, method of measuring .r-rav of anti-rosiipcrior s])ine of 7(14 dosage, 1155 ilium, radiography in, 1071 Frilling of film, SOO, SO 1 transformer, 748 of carpu.-, radiography of, Frimaudeau's interrupter, 102 outfit for high-frequency 1000 Frog's legs, contract inn of, (!al- work, 5i:-; of cervical vertebra", radiog- vani's experiment, M14 principle of, 744 raphy, of 001 Frontal sinus, fluoroscopy of, safety-valve of, 715 of clavicle, iluoroscopy in. b 'fore radiography, Call-stones, radiography of, lO.Sd O7.'i -07(1 inis. S>e a so biliary of coccyx, radiography of, danger in, 071, 07.~> calculi. 10117 ' liigh-friMiuency ( urrent to, Calvanie cell, S2. See also Vol- of fibula, radiography of, 1120 tiiic r.ll. 107."). 1(17(1, 1077 normal, OsO cell-baths, 14:-!. 415 of finders, fluoroscopv of. of empty skull, OSO, '.M tor chorea, 510 1102 radiography of, OHO tor locomotor ataxia, 443, radiography of, 1 102 anteroposterior, 071 5 1 5 ot humcni-, iluoro-copv in. dUiphragtn for, 07S for neuritis, 1 15 Ilisi;, 100s distance from tube to current, Benedikt's applica- radiography of, lOOs pate, 07H tion, 5(10 of inferior maxilla, radiog- fluo-oscopy before, 07:;- electrode- for, ,'isO, .'-',x:-J raphy in. Ols 07(1 expectorant effect, 134 01 li.uer ja\\ , radiography of, lateral, 0(10 faradic current with, stim- 0(15 plast ic, ssil ulation by, ls.5 ot mctacarpal bones, radiog- raphy in, 1 100 position for, 07:!, 071 ftir acute gout. 125 for anthrax. 42s of metafarsa! bones, radioLT- of operator in, 07s for atonic dyspepsia, 431 raphy in, lUv~, relat ive po-itioll of tube, for blennorrhagic arthritis, of neck of feiuiir, radiography )i ate, and iiat ient 's 121 in, Kins in ad, 072 for bronchitis, 43 i ununited, ra diographv stereoscopic, i>7."> tor broni-hopne unonia. 134 of, In71 tei-hnic, 0, s for bulbar para ;. -is. 17(1 ot odontoid f)roeess, radiog- time , [ exposure, 07S fi ir C( rvici ibrachial neural- raphy of. 001 Toll-ey's device tor po- gia. 50(1 ot i ilecranon process c .;' ulna. Mnot;inir ,r-ra\ tube for cicatrices inter b'.irn.-, radii igraph v in, 1OOO for 'dl 127 of patella, radioLTapln in, head trnueto indicate fi if con.stipatioi . -431 107 1 m ei 1 i a n o ' : i n ' ' 7 * in Iieurasthenia, 52'1 unio,, . shown bv radiog- !at, ral plat. '-holder in, : >r ci iiit u-ion-. 42d raph;, . H)7:. 07 1 for cutaneou- gangrene. ;27 oi phlanges of foot, radiog- t TI ::' illg ' it plate, O7'l for deafness. 1M1 raph;, in, Ins.", v a 1 ii i , 07'.' ti 'i- dr\- otitis ::. dia, ', ' of hand, tluoroscopy of. \\i: i pati, nt lying face for Duchenne-Krl p - . ! 1 1 12 do-A,,. 07H, 071 170 radi..grap!.\ of, 1 1O2 fare Ul>, '.'71 for Dupti;. tri'ti's :." - dt radius, radiographs ot, b 100 on -id,-, 070 tion, 12ti INDKX " r ( ;'.;'.--:!->-, (ialvaii!' 1 riirri-nT lot tubotvm- danniia-radii; m ra\>. 1211, 1 JU !.;i paiiiti.-, i:-;t ab-orption b\- ua>e> and : - liyi si -. l_'o for nr: ii-aria, tL'7 liyht and lieavv .-ub- fin :. : i, i_'7 fi r \ ii iliL-i '. 1_'7 stances, !J7,:; for eczema, (_', for \\ nlfi-'- i-rainp. .", I'i origin of, ]_M:-! for electric baths. 1 1-'. See jimiTal inihi-at ions for rf- ])roilneed bv alj.'na ravs, . ' fci-tr- of, !-'t ! _' 1 _' lira\'\ , lor roiiMipation of secondary, l.'ol for ' lephantiasis, 1-7 IH'i:ra~! hi'iiia. .">_'i'i produced bv beta ra\'s, 1 - .-. 17'.i inti-rruptcil, Im-a! anc-tln'- 1 1'.'. 1 for i-r>>ip.-'ia.-, L'7 ~ia from, 7,:;n (ianclion-eel!- of anterior i-or- fc ir er\ tiiT' imelai!_ - ia, 1_'7 for lii-oiii-hial a-th- nua oj -pinal cord, electricity fur exophthalmic Boiler. ina. .".:!( I from. L'lis o_'l ' fi ir i;,!::: ;i ini-, o-'.i > ( laiii-'ri nc, ciitanei ills, slat ic f ( ,r facia! neurahna, ,">()!, iiioilififil li\- i-onili-iiM-r.- in elect rieit\- for, 4J7 .".1 !.". parallel, 1st diabetic, roonator etlluve ., .- ,' -is 17-' rlit'otoint 1 Is 4S'J svmmetric, iralvanic cnrretit for traiiL'reiic. .- \-iniin-tric, >tiinulatioii by, 1M for, !L'7 t_'7 tlicra])c-utii- clTci-t^ of. }.'_', Oarment>. j--ra\- proof, s(l_> : ira.-tri ilisi a.-cs, 1-1 l.'.'i tias-eiifrine, iKnan.o driven bv, fur Hi iin irrheal rheumatism, to pneunifipar-trir nerve in i_'i; }J1 L'a-trir diseases, tMl Clases, elect roly.is of, IJ14 for headache of nervous in neurar-tiienia, '>->>, ioni/ation of, iil_'. Sec al-o dyspepsia. .-,:>ti ."i_'7 ]nni:'it'"n "'' '.,"' ft. for hemipli iria. ~>17 trratnii-nt l>\-. 44ti ion> in, velocity, L'lil - :..;..-/ .-t. . i-. electrotherapy, examples of, transmission of electricity for hydrarthrosis, l_v. I.'.' through, ])he!iomena of. for h'vpiTpla.-tic utitis, 4:?4 exritahility, .'jss til_' for hysteria. 5L'] anonia!ie> of, !iil Clas-fille.l IJi'.nttren-ray tub". for hysteric contractures, exhau-tion. 4iil advantage of, 7^'. 4s:; formula, laraili'- liy;>o-ex- .-ea^onintr, .s:5!l paralysi-s Iv'i citahilitv with. :-','.n ' \\ ith iinchantred vacuum, for i'-htin ,-.-. !_'7 hyperexeit'ahility, :i'M tnillainpcre.-. and back- for impotence in neurasthe- hypo-excitability with nor- up in, relat ion bet w ci-n, nia, .">:>.-> mal formula, faradic hyjio- s:il !L".I inver.-ion, Jiil -pi i-d of, MIS' for infantile i-cn-hra! palsy, los.--, 4f,l Gastric. See Slmwirh. .M 7 [iiiiM-iihir valve, ^'7M Gastrodia])haiiy, tluore-cent for it.'hiiiL' of lichen nihcr, ,-i-ali- of IK uri unuscular <-x- media for, 1 j:C> tl'7 citability, 4.,f, ( la -tro- intestinal ra for lichen, 4_'7 Clalvai autery, JO:-; CJa.stroptosis, tadiourapliy in. for ! icomotor ataxia, ~>l~> blade>, :;s:-;, :iM K ):{(), 1 ! ni ,.-!.:.!!. ~i'2~i, "i_'ii !'>:; (lermatit i- in, 1 L'I I'.i cephalic .W, in.-uiat inii \-ariii.-li'-.- lor, iieero-i- oi inte.-t ine in, : tn irii -. :,MH L'lL' 1 _'(M 1 : - . tL's (l'Ar>onv:ir.- movalile coil, tn tment 1 ubi . 1 Ji 's : oli-ti-fri'' para!y.-is, 47'.i !'!.' (lei.-- ler decree ol exhaustion. pi - '. 1J7 i lei-troina^'iietic, 17:> 1 i 1 1 i for p IMVI ti-, .'. ! 1 Sn . ; -'. siiii tub. s, tin; i . oil \VeMo.r-, vt',0 as vacuum electrodes, ti.". 1 : i pi irii; ., 1J7 ( laifTe'- hot- ire. Mill effect o; iiirht on nciuhbor- : - i: - . , .11- i-i.. l_"i hot uin . 171, -ii(j iiiL' (lases, Ii7i; : -:. i! '. . IJii mirror, I'm ; -.-..!-. eharned particles : r roatini: - .r-, 1.11 needle, 17:i in, 7l:i in . , - . :, 1 1 j di \ iation- in. UK) showing cathode stream, : 1 1 i i ." i 7 , .",i i -. n -i-taiie, ,,:, 171 I',.",] roii.-rii.a, 1 J''. shunt n-i-tiinre and, rela- -pccial form-, ii..l tion. |--x, Is'.) (ielatine. demineralized, elec- . - Ii, _'n:', ,' 't'r'i'e'd'ialy-is, L'.")S ' ' -;.'!-: o! i \ 1 1 r ! 1 1 -ill! . I'.'l conduct ivity of, L'.'is - . : .:.. i:;n . 17:; . . -I ropositive. _'.".-. . !.'..! Snool . tn.i iirni tic, Slid ( 1. m latintr electricity, m< m- toi.l palaK - fan-." nt, I'.'H .-:. Is ; 77 liven. of. I'M ( lelicrator, elect ric, Jioitabli-, . .,.,' 'I In : p onV i: irror. I'.K) foi ..--: iv vvi .; k, T':'i'i to men in nterii 1 ' re- -ttince motor, direct current, lor : - -.",;] ol VO lair eell, '.Mi vo'tai to r. 'ii;cc t iol !e\ -car eur- i. lit. L'l.'i two-Ill . die. 171 unfluctuat mi' lii)'li-|.otciit ial U i -ton'- i l.-etto! iirin ti' . t.ani r-iirrent, 7o" >!,! 1 , lllllectilied tl ' 1 ; , , 7 < ,..-.:: o... n . . eli-'trode- a-'. 7 i:i ; , ,, ;;s:; i .. ilate iranu'Hon, inflan ma- '.7 . . - - ; 17 1 ' 1' (I,.,,,, .... ,;,.... .'i : . 1 1 ii ',.-;,,)' ciii " nt foi , .".v; . . , i - 1 : ;.,__' rent lor, ,",s:i INDKX flenito-urinary tuberculosis, filass \-acutim electrodes with Grounded body, induction in, 23 hinh-frequency current tor, d'Arsonval current, effects, ( Iroundirm a Coolidj/e r-ray 5S 1 .">71 tilbr-, 7s_' ( Inn; valu'iim, rai lit >trraphy of, Glossolabial paralysis, 17.'. one- ],o!e oi a batten , :;i,l 1H7.". (;loss\- velox paper lor dental of a step-down Iran-for- ( lerman hiirh-frequcncy appara- radiographs, '.i-:5 mer, 'Hi.") tus, 552 (Hove.-, protective, in dental static machine, :j(il s-i'.vcr, fusitifr-point of, 20'. i radioj-'raphy, !'_'."> Grove cell, '.H win-, resistance of, -1'.', 2:5:5 j--ra\ -proof, Sl)2 (luillemmot spirals, ~>~>~> ( ,i station, radioL'raphv in, 1 1 .'i 1 (How discharge of static elec- double, autoconduction by. Gilbert, 12ii tri.-i: \ , .".. ).>.! Gland-. elYect of electricity, .'502 ( Hyceriii, nidiferous, 12(i(i hifih-tension current- from, ( llandular secretions, static elec- Ciiiter, exophthalmic, hi^h-fre- .").")."> tricity and, ,"1 qilenc\ current in, ll'.Mi- technic in arterial hyperten- Glass electrodes filled with 1 l'.i>, sion, '>'>'-> liquid. I!'!' radium, in 1U7S Guillox's stereodioKraphy with- in hij_'h-frequeiic\ apparatus, r-ra\ in, 1 I'.ni out stereoscope, sis 22(1 ioiiiu anaphoresis for, 100 techni<- for cataphon-sis for insulators, resistance of. 221 x-ray in, I'.i. trout, IDS, mount for dental films, Tou- Cioldber-'s law, (l.sl) .r-ray tube, 7715 se\ '.-. Mil Coldstein's kanalst rahlen, 712 Gumma of bone, radiojrraphv plates, force required to ro- Goljri method in studyiii}: cell of, 1 1 in tate. .">(! chaiiL'cv- from elect roi-iit ion, r-ray in, 117!) tor -tat ic machine, .'51 , 37 .-,;;;; Gums," electrodes for, (117 tube.- for radium treatment, Clonorrhea, diathermy for, (io7 epitheliuma of, x-ray in, 1215 1 _'! i I lo.-s of vacuum of. electrode hi^h-lreoi eiicv current tor, 5S4 h ifih-1 n 'qiiet lev current to, (11.-) properties and. 5(1(1 r-my for, "),S5 Gundelach's \vatcr-cooled x-ray vacuum electrodes. :>s|, ,">!) 7.\!\i- elec:ro!\'tic medication tube, 7ti:; connected with induc- in, !l)7 x-rav tube. heav\- anode, 7(10 tion-coil. .")(')( i (lonorrheal arthritis of knee, 'light anode, '7(12 with pole of Tesla iodin anaphoresis for, Gustatorv nerve, reaction of. transformer, 5(15 11)7 17(1 with stati" machine, radiography in. 111^ Gutta-percha as insulator, 225 5(15 rheumati.-m, caivanic cur- (k'ctrost;itic capacity of, 225 and I.eydeu jar, rents for, !_'.") for iiisiilat iiiL', 5'.i 5ti(i stat ic wave to prostate for, insulation for j-rav conduct- effects through clotliinsr, 77 inn cord-, 7:57 ."7i i (ior! ultraviolet lamp, I'iffard's resistance of, 221 for abscess, WO nuxlification, H7(l Guyon'.s treatment of incon- tor acne, (125 Clout, articular, radiograph'.' in, tinence of urine, (2(1 for alopecia, H25 11 Hi Gvmnotus, static electrieitv in. for ai>pendi"itis, (ill elect ric-li<_'ht baths for, 40s. '.".1 for calculi, 5sr, (i s ^ (Jynecoloiry, high-frequeucy for ccllulitis, <12!i galvanic currents for, 42."i current in, 5s] for chilblains, (i2(l hifrh-frequency current for. h\-ilro-<-lectric sitz-baths in, foi chorea, 5 '.12 ,")7."), i;u.") ' 447 for colitis, ti in lithium cataphoresis for. His for constipation, 1110 merciirx vapor liL'ht tor, tiv.l for diabetes, 57'.', 5!l!> radiosrapliy in, 1 ! Hi HAIIKI; process of obtaining !i r 1 )upuyt n-n'.- contrac- radium i rinkins;-\\ ater for. nitrate- from atmospheric air. tion, 5117 l_'ii.") "jS l'o'- eczen a il'M rheumatoid, radiotrraiiliv in. Habit spasm, electricity for. 51!) fur cpithelioma, (12! 1 1 Hi, 117! Ilaljitual constipation, elec- for furunculosis, ti2i tissue oscillator for, (id! tricity in. !:;! for trout , (i(l."> (lout \ deposit-, thermopcnetra- Hair, loss of, from x-rav, 11:55, for hay-fever, HI 1 .) tion for. ill).") 1 l:-is for herpes '/.( istel . t>27 to,, hu-, 1117 standini.' on end from static fdi indurated cicatrices, ( Irai .. 17-i electricity, 21 Ii27 ( : .:::.-' . :;:-. ill nl . L'lili 1 lair. !: \ i, i-lectrolj -i- for, 1 IS for larynsrit i-. oiv.i C nun-ion, -'liii x-ra\ for, 11s lor lupus er\ t hematosu-, ( Inim-molecule, L'liti Halation', SOU i i 2 v (Iran -[Kirtice. L'lif, experiment, 7'.'2 tor molliisciim conta- '.'. r.'ii Hallux valjru.-, radiotrraphy of. tr i o s u n . o _' s , !_'.'. KIMI KIM I, - : ,,'.. -it; . ll(i:5 l'"l. P<< - - h; . llami 1-1 inn rn:])ter, 141, 112 for painful fiat-foot, .">!! i 127, !Js \Va-n.T, with faradic cur- tor peril j-i i' i -. ii_". i ( Iran liar iid-. hi- rents, !5s. iiin for phlebitis, ii:5O iirri'in !' ii . lils llampson radiomet, r, 115s ''-^ i ; i x Han.l, :'..;,, .;, injected, - . jnj : -.11 25 n 1 p!.-tria. !77 - - . 1 i 1! > 1 for n ' ' -i ' di-i a-i -, >'d 1 lefon if, radi- 1 1 1 ' 1 ' ' i ' ' - ' ' ' i - < ' - 1 tile -..-... li.-,s ..--tt,', -. in. 10H7 ' (ill-' 1 TIM. ; i i i - 1 ! ] ' ' ' ' til 1 : 1 - 1 i. ins.-, ,0s! . ' ' ' ' .... . 1 ' ' - ' .:.! : ':' ' - <> 1 ^ . r:;n s| ! I'M I ' - . ' _' i :. . HIl! pha'aiiL'es of, :- . - '.':' o-i ' oil 1 i , - - . ~:,( i ! , !..- p . 1 '"- i , 1 ,." 1 7l'ii ndi iirra) i . . . ij;,> 1 1 02 "'~- !,-. . ; : ; ; ';-,^!, ll:i ,, 7 . (i . .- ' ' . , Jlli r. MJ 1302 IXDKX Hand resonator, "..'>() Heart, size of, estimation of. Hemorrhoids, diathermy for, 630 raphv'to show, ll'tt and, 1007 rent for, 012 x-ray dermatitis of, 1 1 Ci position of patient in, faradogalvanic current for, Hanfeid tis.-ue o.cillator. 00 current for, 012 H:ii'i>oon and cannula method modified by poisons, 3.")2 sinu.-oidal current for. 012 o* localization. Mi'.i pneumoga.-tnc and, :5"<2 ultraviolet ray for, 001 Hart', electrode tor lulguration. teleradiography of, KMI7 with venous congestion, high- method of liigh-tr.-quency of, 1007 Henry, 141 .-park, lor cancer, .".111 Heat and light, radiant, for Hepatic abscess, radiography Ha\ -lever, high-frei (iieney cu r - war wound,, (iMi of. 1021 Hea.i bri e'zi . 12. I')7-6'J blue-light treatment with, calculi, high-frorjuency cur- rent for, ."iMi po-rioii i,f, in paralysis of from electric current, 210, 202 x-ray for, . r >,s'7 -pmal acce,,ory, 17". from ,-tatic discharge, oS Hering'.- double myograph, .'52,>> radiography of, M t, 002 from x-ray, 71:5 Hermann'.- theory of electro- exposure for, ML' latent. L'Oo ton u.-, L'Mi sen.-ory -\ -teni-, Hi.">, liiii mea.-urement of. 173 Hernia cerebri, fracture of skull Headache in ri'Tvou- dy-pep,ia. mu,ciilar contraction and, and fluoroscopv to differ- galvanic current for, ".20 :;ii entiate, 00-1 ,ick. c :l taphore,i, for, 100 nervous excitability and, :{-l.'5 hematoma of seal]) and, p, . ; it\ and. 40 of ionization, 20o Huoroseopy to differen- static iu.-ulation and head production b\' electricity, 202 tiate. 001 ' breeze for. 71 by electric-light current. radiographv in, 004 Hearing, effect of electricity on. regulation, Mi, s7 Heri.es, facial palsy and, 474 '>' >'2, M'l.'i b\- voltaic pells, 07 neuralgia, clectrieitv in, .".00, lo.-.- of, in facial paralv.-i,, regulation, Mi, S7 501 171 in bod\ , .-tatic el(*-tricit\- zo,ter, galvanic current for, sen.-i s of, I',' 1 and. 71 427 telephone as te-t, 170 in conducting wires. 221 high-frequency current for, Heart di.-ea-e, high-frequenc\ ra\>, therapeutic uses i."..") 022, 027 current for, .".M of gri'at wave-lengtli i,o!a- radium in, dosage, 120.". hydro-electric bath, in, tion of, 00.") static re-onator etlluve for, -inusoidal, H'i. 117 , tatic electricity from, ."."> 7:5 rapid -inu-oidal current unit of. 17:5 ultraviolet ray for, 001 for, 1 in. 1 ! 1 I leater coil of platimun, 201 H.-rtxian waves, ."".1. ".00 .-inu-oidal current in. 1 12 Heating effe,-t.- of static di Hertz', experiment with cath- static elect ri'-it \ in, 7 1 charge. .".', ode rays, 712 till ' - : dtern it inn currents ol 1 L--UC, b-. electric current-. Heterodyne, Cabot. 7.".0 on, :',72 20 ii High x-ray tube-, 70:5 of break-r-hock on, :',7 1 Heberden's nod.-, 1117 re-ult, from, xlO ..:.: k on, :-:7l Hefner, li.'.7 High-frequency apparatu,. .">:{!) o: c,,n,|en,er di.-charge- on, HI ineeke'- experiment, 011 et- conden-er, for, :;7.".. 107 ;-;71 fect ot x-ray on marrow, 1 1 12 I.evden jar, as, L'i'.O rj| :.:...,,.- i-irn r.' on, l|e:i.z-Haui r <|iialilncter, s. I. lioehetort', monolith, 2oO ,7. , X \~t d A'-onval. oil. .".10 of high-tension current - on, Heliotherapy in chronic' in- effect- of working near, :i()7 20". fect ion- o,teomye!iti>, 001 Cerman, .V.2 of 1 A -ten- ,1 , - on, H. Ii in from radium, 1 2..2 gla- in, 220 20.' ga- in j--ra\ tube-. , .;.", l.e-,ien jar, as part of. ot ri aki -hock on. :;7i producfioii of, 12.'.2 107 (.en ing -1 . :. ,;7 i quantity of, 12..2 i ludin, .",11. .".is ot '-Mi'.'ulvi'on ~'l cervical Helndioltx laradic coil, l.'.s, l.'.O Tesla'.-, ,')(], ."..".1 -,-. ,1 ; i > rent lor -t imu'.at ion, .',.','> coil, :.;.". ... .' _, 7s II, rnaton a o! -i alp, fracture ol : , work, Ti l:t, 712 i it ol, in lock jaw, -kull and, fluoro.-copv to current, r.itx. See al,o Ui- . IT. r. ntiate, O> 1 1 ;,.,,. een |,ri and fluo- ,;//,. rn, i. flei irethal ,','' rol\ -i-, r-o-cop\ to din. i, ntiate. . ''07 '.ill 1 alter rial ing dii rent tor, .". 1:5 -. :/ . . |IK)7 .... . , in) amperage of, m> a-uring. ri, .",.;.', Her . 17." 7:,s 11 ... tubel II, miplegi ,. 170, 177 ane-thetic effect of, after . >..> urethral ele. lrol\ -i-, ,".Mi ' ...-.. lor. :,lii, r.17 application, .V.2 1 1. tin ,gl 'bit., . tie. t < ,! x-ra\ on, [ J, .more, ci ' au't'ocon'du', ti,m cage 1 ,r, ortl . ', O'i, . '('.is Hcmorrhagi ti in hiL'h-ten-ion .",17, .",."..'. , irrellt-, L"i."i, 2'i bacterial effect-, .",1,0, bipolar rr-,onator lor, .".."il, ... . , . . ; , , i ; , , . i . ; , T i ,, .... [ i in . 1 o i.i : . ..--,., ]_ ' effect- ot, r,17 IN'DKX 1303 High-frequcnoy 'current by auto- High-frequency current for epi- Iligh-frerjuenc\- current for pul- conduction, 553 lepsv, 501 monary tuberculoMis, H07, capillarv vasoconstrietion for epithelioma, (121, 1210 11. SO from,' 579 for erythematodes, (12! for pvorrhea alveolaris, H|5 rataphoresis with, 4 1 1 for exophthalmic goiter, for Ravnaud's disease, 583 condenser electrodes for, 520, 1 IDS, ] 100 for rectal diseases, (111 563 for eye disease, (Us technic, til 1 large size 5(15 for facial neuralgia, 503 fistula, (113 crown cfiiuvcr tor, 5(13, .If 14 for fibrous conditions, 597 prolapse, (112 d'Arsonval, application, for fissure of anus, (112 stricture, 013 351 for fistula of rectum, 1113 ulcer, (113 ozone inhalations with, for fiat-foot, painful, 50(1 for renal calculi, 580 Go for furunculosis, (121, (127 for rheumatism, 575, 509, small solenoid for, 552 for gastric atom , (KM) 1100 transformer for, 511 diseases, 009' Tousey's technic, OCX) definition, .'50 for gcnito-urinarv diseases, urine in, (100 desiccation by high-fre- 583 for Kigg's disease, (115 quency sparks, 5(10 for gonorrhea., 58), 585 for sciatic neuritis, 505 for hemorrhoids, (112 for gout, 575, (105 for sciatica, 507, 508, 503, for hvpertrophied tonsils, for granular lids, CIS 504 fi 1(1 for hav-fever, tl]l for seborrhea, H28 discharge of, simple, 53s if t , -j(\(: for heart disease, 581 for sinusitis, (11!) cilects, ouo dee]), 5(10 for hemorrhoids, (112 for hepatic calculi, 58(1 for ^kin-grafting, (12!) eliminative, .170 tor herpes zoster, (121, (127 for spasmodic stricture, 584 general application, 571 for hypertension, 57(1, 577 for sphincter ani paralvsis, local, frtlX, 570, 571, 57:{ for impetigo, (121, (127 613 on animals, 573 for impotence, 5S7, (113 for sterility, 433, 5S2 on bladder, 570 in neurasthenia, 525 for stricture of rectum, (113 on blood, 571, 575 for infantile paralysis, 570, for sycosis, til'l on hypertension, 57(1, 577 500 for svnovitis, rheumatic. on man, 573 for insomnia, .">!>( 500' on mucous membranes, for intestinal diseases, (i'vt for telangiectasis of nose, 5(1!) for joint injuries and dis- (121 on skin, 5(18, 574 eases. 583 for tinnitus aurium, CIO on urine. 575 for k-loid, (127 for trachoma, (118 pathologic, 3H7 for keratosis, (124 for trifacial neuralgia, 503 physiologic, .'5(17, 50s for kidney disease, 575 for trophic diseases, 583 systematic, 573 for larvngeal cancer, (100 for tuberculosis, 570, 580, thermal, 575 tuberculosis. H07, t'l'ls (107 eflluver for, crown, 5(18, 5(14 for larvngitis, 00!) genito-urinarv, 584 electrodes for, 380, 408, 545, for leukorrhea, 581 of bladder, 584 55! I for locomotor ataxia, 515, of kidnev, 584, 1180 eliminative cfTeets, 570 502, 1102 of larynx, (107, G08 Fleming rectifier for, 53'J for lumbago, 5!!3, 501 of rectum, 5s 1, for ubseess, (130 for lung diseases, (107 pulmonary, (107, 1 IS!) for acne, 1121, tli>5, 1171' for lupus erythernatosus, for ulcer, (120 for alopecia, 1121, t'i_'5 H2s of rectum, (113 for anal fissure, (112 vulgaris, (121 for uterine malpositions, for angina pcctoris, 581 for mediastinal Ivmphatie 5s 2 for appendicitis, lil 1 tuberculosis. ll'SS for varicose veins, 57n, tii'O for arteriosclerosis, 575, for met rorrhagia, 5.S2 for vcsioulitis, 5s(_i 600 for moles, (121 for warts, til'l for asthma, 5, 5, Ii07 for molluscum contagio- for weakness of sphincter for atony of stomach, fiOH snni. (12s ani, c.12 for atrophv *:< d'ArsonvalV, 05 for eervicobrachial neural- for ozctia. 'il'.i (laitTe's transformer for, gia. 50i i for pain. 5'.i(, 505, 50il 513, 713 for chilblain, ti.'il for paralx sis, 5O( I general applicatiuns.effects, for chorv:,, 50l> agitaris, 501 571 tor cicatricul conditions, infantile, 501 (lui leminot's, for arterial 5' '7 of -nhincter ani, (113 h\ perten-ion. 553 for colitis, till) for I'a'rkinsi n's disi a . 501 ted, m.. 553 fur cniistipal ic m, 57 hand resonator for, 55'i tor const itutinnal disease-, for pert'i .rat ing ulcer i >i foot , high-tension. 551 507 (120 effects. 574 f, ,r c; -1 :i is, 5.X<) for periostiti-, 1120 local, 5118 for defective metabolism, for phlebitis, 5, (>, (130 in gynccology, 5M 5 7 5 I'* if pli-urit ic pain-, 5'.Kl indurated-iiber couch for, fur dial). 1 >-. ."'7'', 507 fur i'! ign ssive rnusi . 515 : 11 I Jupuvtreri's coin rac- atrophy. 51 t large si ilenoii 1 : ,r. 553 tion, 5'.)7 for prolap-e of rci-turn, lighting ineandcsei ut . for d\ -pi'p.-ia of neiira. ('.!_' bv, 511 thei :. 527 .t ititi-, 5.M1 l,,,,il effects, 5lis, r,f,0, 573 for ear disea-es, til'.l tor pruritus, i',2s locally, 55H for I'c/ema, I'rjil ani with cr/cma, (113 measurer:,, nt in aut' n-on- with priiritu- ani, 013 for p~, iriasis. (ijs n, 517 for epidid\ rnitis, 5SJ t' ir piilnn inary diseases, 'ii >7 of os ' . " i , 1:504 INDKX liph-freimency current, mf-tal IIiph-ten--ion currents, thera- Hydro-electric baths for progres- c-..nili II-.T electrode- for, peutic applications, harm- sive muscular atrophv. . , . ,d I, ., 1. --n,-- of, 21 ; :>] \ l of appl;. iiiL-. .-.",7 hiph-freiiuency current, VV 1 for >kin disrascs, 42G mon. .lnh condenser for, VV2 effects, V7 1 four-cell, liili rnu- .: ;i ' ,nl racl i, ,n.s by. local, VliS nalvanic, 1 i:i .". 7 ii for neiira-t h"iiia, V20, V27 for litihtiiinp pains of lo- < >udin. ."..M t ran.-former, 7 1-i coinotor ataxia, 4 4:j re.- nator for, ."4s, VV:-> Hip-joint, di.-location of, con- in sciatica, 44){ ,i : .r. WO genital, radionraphy in, phvsiolopic effects, 442 o-cillatory character of, V:-;s 1071 i)olarit\ and. 4 l.i os, ill., -cop,- f,,r studying. radiography of, l()(is induced, 442 7:;s tuberculosis ot, displacement.-; larne silicic, 4^7 m, VO'.i in, 1070 shovel flc-ctrrxle for, 4:js patln doiric effects, oO'.i MeCurdv'.- transpelvie .-inu.-oidal, 44.") penetration- of, ."7 line in, 1070 blood-pres.-ure in, 4iV, per;- 4 dti eft, cts. .",7 1 radioL'raphv ot, loii'i ! Hi plr, -i ,|i mi ', -. ,'jlis, VOx roiiiprc'r-BUjn band for, effects of, 440 rectiiii-r tor, Kleinm", Vi'.i 101 is in cardiovascular dis- re-.iiiators :or, .Ms, .V.."., plate-tunnel for, 10(is ease, 44V, 440 ,Vji; reduced radiability in, U','.i in In-art disease, 410. rheo-tat for, 7.;o -ipn.-, lOii'.l 417 Koch. .Jon resonator for, ]\irr/. compa.-s, x(i!t pruritus from, 1 10 .,...,, . . o Hodckin'.- di.-ea-e, /-niv in, uses of, 110 it ion conden-er elec- 1 ins switch-board lor, livS trode for, V01 HotTa'.- tcchnii 1 for injer-tiim triphase, 417 solenoid tor, small, W2 ox\-(ren into joints, 1074 effect-, 417, 44S i-park di>i liarpi-s from, ef- Holder-, exposure, for films, sin tub tor, 4:i< fect-, vo'.' Hollow \\ooden electnxle, u.-e with negative electrode at -ystematic , fleet-, :,7:-', of, t'.S dorsum, 4 Cj Ti .-la, WU 11 An. ,-tat.ic machine, :', l-ii7 with positive electrode at Texeira tran.-former for, -tartitifr of, :;i. 11 niicha, 1 i:', .).").") Toepler machine to ex- sitz-bath.-, 447 thej-mal effect, V7V cite, : j ,2, :-;:! Hydrogen electrode for mpas- T ' ' trOll til! -Ill . - , 01-', ' -' 1 - u. n .-. 01." 1 1 ' >'./. K IK ' 'I i* - ' '! i roniorjicixoi) i- eter, 1 lV:i. 11V1 e eetrode, 17s Iran -lor sner for,d'Arson\~al, unit- at nkin di.-tanee, 11VV r-ntrance trf, into ar-ray tube. V 1 1 treatment of fa\ii.-, 701 1 C, dffe's, vi.;. 71:; 1174 liberation of, in voltaic cell, s:> Te.-la, VV1 HoorweuV formula for ,-tLmula- to reduce vacuum in x-rav T. -... ira, VVV tioll, oSS tube, 700 unda:: p.-d ' ,-ci]lati, IHS in. 11 ,r-.-power, 171 x-ra\- tube, , 07 c,:-;.' Hot air for moi.-ture in ,-tatic ]I\ dronei.hro.-i.-, radiography of, vaci.um electrodes for, ."IV, machine, 40 1002 .V.'.i. See al.-o i Hot-wire galvanometer, 1 ,4 Hydrophobia, radium in. 12(11 . . - ( :..,:;. '-. si;ii H\ peiaciditv, radiocraphv in, vr.lt ac" of, measurinir, 7:;s r r . , , i 1 t , . r - r ' rnilJampercmcter, ]~>\ '102!' 1 1\ t M Te\ ci t at ill it \~ .^''1 401 .. - , ' ' ' 1 . C ' I , . M , if, .".:;' alt, inatintr current, 21 1 ilyperidrosis, x-rav treatment .:. ' ' . HI ../. VV'i IIour-irla>.- -toma-h. radion- 'for, 1 177 linn of term, l''s raphy in, Hi:iO, KCil 1I\ ])( rstatic cutr nt, ."4 , , Vis -et , .". t 1 Hnl!'- apparatiL- for x-ray work, 'transformer, Piffard, Vis -; irk- i - can r, ."'.1 7V s II.;, rti i. -ion. arti : ial, dia- dc-icr-ii ion : -kin from, Hul-t'- teehni' 1 tor fra-tric radi- thc rmy in, (ioO ipraphy, 1(1 CniUeniinot'- autoconduc- ,.-; , - : -. .VKI II in n li-.-ue-, ab.-orption ot t ion for, Wi . . d".i- - 1 . , .,7 inducto-resonator eflluvc - .". si ; Humei fillo: . i[)V of, lOsi; for, 7(1 for pa;! : tuti of, fluoro-'-opy in, aiitoeonden.-ation pads tor, .-, VOO - i ner, ID'.I'.I aiitoconduction cafe in, V7o. .!.. -,Vii radioci : of, 1 0'.i'.l V77 - : '-, 7.;.; .- tel ' ,,..,-., -It \ 01 ! rh- frei |iienc\ cuncnt in, -.- 7- ... t, 1 f. Id! IS .'. 7' ,. V77 - -.'. iry ol, i. nttri nization of snptarc nal . 7 . ; .- 'raph.\ . 10:0 , ap-ule for, 1 KH . T .'-,' Ial current.- for, 1 1 1 . KISS '. , 1 1 M , : 1 1 I o i , V s , ' ' ' 7. 1 - , t;;r< .,!, radi :'- 11;, p, -h\ loidi-m, iodin !;. ' .7 KI'I'.I II; pell 1 , cll-etl . - , - , - M. . . . , I 1 -. ", - . ^. \ t! 'ity lor, e! i;,,l; -i- tor, ".no, :>:;, 1 1;;. ; i ; , 1 1 v . in -in, 12,ii a in. 11 7:1 : . 117 : liver, -talic -A IXDKX Hypertrophy of tonsils, high-fre- Incandeei-ent lamps, reflector Induction-coil, manipulation of l|llelie\ doiccation ill, li Id tor, non-loi-iir-intr, tiii.'j Coolidge tube witli, 7s.", uf ; n i buiated In me--, ioni/a- resistance of, (;.")S operated bv <-l<-etri'- light 'ajr- tinii i ir, Hi7 rub\, s71 I.I', 7 1 ! 1 !!\ pnotie effects of .-tatic elec- tot's of, I')."i7 1)V galvani'- cell-, 717 t;ii-it\ , 72 tl;era[ieiitie, (M.S-lil'il power of, Io2 Hypo, artior, of, S71, s7.">, ('77 voltage of, li.").S soft-iron con- of, 1 17 lor plalo. ssl with reflector. C.."S Spot ti.- wood's, lot for print.-, ^M li^l.T bath. ].h\>io!oL'icefTects, 12-ineli rheostat lor, 7.',0 foniii;!.-! lor, N77 ti.S'j voltage of, i.v; Hvpo-aeidit v, radiographv in, temperature, lis.'i watts of, i.-)2 '10-'! 1 therapeutic effect > of, (iMl without iron core, -eparate Hypochlorhydria, static elec- Inci])ient cancer of brea.-t, bi- electromagnet for, Io7 tricity in. 7"> polar ioni/ation for, 101 Inductive capacities, ,-pceial, Hypo-excitability and shi<_ r <_'ir-h [ncisors, lower, radiojrrapiu- of, 21 o contractions, :-!!il s:j4 re-i.-tance, ."> 1 , ",!( faradie, uith galvanic for- uppc-r, r:idioyraph\- of, (l.'il of voltaic cell, !K) mula. ii'.M Incontinence of urine, elec- Inducto-re-onator aetuated by galvanic, with normal for- tricity for, 7:i, 42M static machine, , o mula, faradic hypo-excita- Index-finiier, reduplication of, effluve, bipolar static, for low bility with, :park-, 'ili and breeze, tis tor paralyzed and atro- phied n.u-cle- from Hypothyroidism, iodin in, Oo7 electrode, 117 war injuries, 7(> 1 ly.-teria. I'lcrt ricit y in, ">21 spray electrode, Tousey's, 0!) for arterial hypertension, in paralvsi.- after injury, ma- .-tatic bree/e, (Hi, (17 7ti lingering in, -iCO for neurasthenia, ."i2t for asthma, 70 for brorchiti- 70 primitive character o!, ->21 p.-vchoneiirosis anil, differ- Induced currents, l-^.'i cause, 1M:< for diabetic gangrene, 7(i entiation, .">21 faradic, 1> 1 7 for ton.-illiti.-. 70 syinptiinis of, treatment, ,~)21 for ,-horea, r>10 ftr<},,.ir\,. li.i t ti ll'> Indurated cicatrice-, hii_'h-fn- Hysteric amain'osis, lv> aphonia, 17.">, is:-! ior electric Darn, \\ for exophthalmic goiter, .">20 j-ra\' for, ti27 bnlhar palsy, 470 for neurasthenia, ~>'2 \ Indtirated-fiber couch, old contracture's, ISi for poliomyelitis, .">14 Induration in traumatic arthri- paralysis, l>o for s'-iatica. .">()! i tis, static wave current and vomiting, IV! for stimulation, .S.'is, l!)o sparks for, 71 in parallel wire-, l.' Indii-tria! currents, death from. in ,r-ray primary coil, S.'iS o:;o. ooo, o.'-;o isolated shock.-, curve of, Inert ia,- maL'netic, 1 1 t li HTHYOMS, static electricitv ISS of water flowing through in- tor. 127 for facial paral\'sis, 4 i 2 clinetl tube. 247 Ileum, radiography of, 1020 for incontinence of Infant stomach, radiographv Ilium, anterior superior spine, urine, 42!) of, I02!i mii-eiilar fracture of, radi- stimulation bv, ">()!) Infantile bulbar pal.-\-, !7ii ography. 1H71 laws of, i: c.rcbral pa'.-v. elect ricity !' >r, [linn matioii, vacuum tubes for, static, ',.",. See also St " 517 o.">2 ;,.,/,;,/ current. paral;. -..-. high-frequency cur- Image .-how ing on ba. k of film, study of, T.-JS rent for, o70, .">!'(i 040 to heart, :{ol static wav current for, .'>13 Immobilization, methods of, undiilatorv nature of, loo spinal ]iara!\>is, elei tricity 10! 11' Inductanc,. rcjrulator, oil fi if, ol 1 . r-ray and, !2o*- unit of, 1 11 Infected plinct t;r>'il \\-i ii;nd- Impetigo, hiL r Ii-frci|iie;:i-y cur- Induction, charge by, 21 wit! fistulas, copper rata- rent for, 021 . 027 electromagnetic, in powor- - -i- for, tut 1 , radium ra\ - in. 127c housc. 2Ui Infection, dental, symptom.- and -tat i' 1 elect ricit \ 1< if, 127 in ttrounded body, 2M lesion- due to long Impolarixahlc electrodes, .'74 1 1 * \ ''-' |T 1 V ' ' ' ^ ' '7 ' in itiMilate.l bodies, 22 standing. "2'' n-i danger - : '- 'i;;i i 1 > , l; is-He; nioi .1, L'7! elect ric eiirn-nt-, 1:12 his.'li-fre(iuene\ ("irrent for. In.luctic.n-coil, i:;:; iti .." ;!.-. reatment, "'.' osti, i;iu and stora ire-battery for .r-ray I nfectious di.-ea.-i -, .r-rav in. in ncurar-th'-iiia, L'alvanie work, 71S I2.SS curn i.i ; ii . ."ijli i ir, 2:;o. LM2 Inf.-rior dental canal, radiosr- urn nt n. Its 1> if, " L'I'I i maxil . >ic if, . ;:- l,'i \ naiilt 's, L'7 ! 212 ' , "i 7 1 Iicaip le-rence, t'i,"i."> win n n ijuired, 2!o it i. 'ii of, radii igraphy inten-it; ot, li.Vi ' - . 1 .Vi law oi. i ;:,.-, i. 212 pi r. i : tun nf. d.Vi . i .':.'. _' :.: [its [,,, ..,,! | . r ,l,y of, !IJx, -.,-, i'.'i_>, iv;i '.II- tierv . den-td; rad :rap] . i i . 7 1 _' ; .711 ".I . ( ' ' x . , i ,'' '" ' : '''-."'' '.' '' : -'- r i.'i s .... . . . ' ' . ' - . - - , , . - - ' , .... - _ 1 ,, ,. , . .' ' ','-" ! ' - - '-.! 131 Hi INDEX Inhalations, ozone, with static wave currents for chronic bronchial troubles, 77 Inhibitory nerves, absence of, in voluntary muscles. .'Mil Injury tiom .r-ray, 1 1 Hi to brachial plexus, static wave current for, 47H war, physiotherapy and elec- trodiagno-is in, -151 Inner canthus, epithelioma of, .r-ray in. 1212. 121d Innominate artery, aneury.-m of, radiography of, lOOti Insaniu , elictricity for, 522 In.-ide wiring. 2OS In.-omma, high-frequency cur- rent for, 5! Ml neura-tlienic, static in-ula- tion and head breeze for, 523 Matic electricity in. 72 insulation with head breeze for, 72 Instantaneous radiography of In.-ulatcd bodie-, charge by in- duction in, 23 physical effects of Mafic electricitv upon, 55 ele.-trode handle, 3S1, 5511 high-l'reijueney tube-, 551 metal hall inside hollow metal sphere, 213, 214 platform, -11 In.-ulation, air, 223 cement, acid-proof, 213 materials, 5!, 212 of heavy currents, 215 of human body, 211 - ot .-ilk, 212 of wire-, 223 material- for, 511 of wood, 212, 213 of j--ra\ conducting cord-, 73d paper/212 requirements, 20 s, 201 re-i-tance of any circuit, measuring, 212 testing of, 20H -tatic, d() effects, 305 in obesity, 73 tripe. 212 In-u!ator-, 25. "id'.l, _': If la.--, re-istancc of, 22! / , : pereha, re-i-tanee of, 22 I pi reel lin, :e-i-t;, n --e of, 221 Inten-ifii r-, -elenium cell, to Interrupter, aperiodic, 142, 72S atonic, 1 12, 72S Heaker. 720, 723 ('aid well. 720, 722 interruptions of, S52 with aluminum cell, S54 Carpentler's, 72S commutator t\ pe, 727 condensers for, S.">7 ( 'ontremoulin, 727 I.educ modification, 144 Draulfs wheel, s:,.-, electrolytic, 1 1') for r-ray work, 720 mercury, care of, 727 dip, 722 jet, 721 turbine, 725 principle of, 720 rectifiers for, 72:! Hopiquet's, 72,") \V clinch, 722, 723 electromagnetic current, Sf>7 for triphasc current, ,s.">7 vibratinfi, 111 wheel type, 113 fc;r alternating current, elec- tromagnetic, S.")7 Villard, Soli for faradic coil, 1.">S for triphase current, electro- magnetic, S.")7 Villard, Soli for r-ray work, 1U7, 720 electrolytic, 720 mercury, care of, 727 dip, 72:i jet, 721, S.")!) turbine, 725, S5G principle of, 720 rectifiers for, 723 Hopiciuet's, 725 \\ehnelt, 722, 723 Frimaudeau's, l'J2 hammer, Ml, 112 Wanner, with faradic cur- rent, 15s, I.V.I Johri.-ton, 727 interrupt ion- of, S57 I.cdu. ,111, 15s, 101 liquid, 1 15 mechanic, 1 I 1, S54 conden-er- for, s57 mercury, can- of, 727 jet, 725. -.511 turbine, 725, S5(i metronome, lor tiiuiti^ my- ojiraph, ,'ils pi-tnlulutri, tor timing myo- trraph, Mis polaril \ of, , 21 (jllc -en \ ibtatilij.', S51 ribbon, 1 12 \Velinelt, 510 . t!i' n w\ of, i :',(', in ciitaneoii.- application- :;si I parnll. 1.' rapid r'adioirraph> v.ith. 71! /-ra\ wall m-t a Hat ion with Interrupterless x-ray apparatus, Kny-Scheerer, 747, 71S Interrupting handle for elec- trodes, 3S5 Interruptions, cliarac-ter of, S52 in primary current, rate of, x-ray production and, 11114 of mercury interrupters, Soli rate of, S51 Inte-tinal diseases, hijrh-fre- quency current for, (iOit disorders, diathermy for, (i3li douches, ^ elastic, 432 obstruction, electric douches in, 132 secretions, static electricity and, 75 InteMine, adhesions of, radi- ography in, 102(1 cancer of, ,r-ra\ in, 122!) effect of j-ray on, 1 111 finding- in, 1023 fluoroscopy, dangers of, 1033 foodstuffs passing through, radiography of, 102S foreign hodiers in, localiza- tion, 102S obstruction of, radiography in, 1023 radio-cinematography, dan- gers of, 1033 radiography of, 1021 bismuth meal for, 1022 intensifying ,-creen in, 1033 technic,' 1030-1032 TouscyV position for, 1010 small, effects of stimulation of pneumoga.-tric, 3411 Intracardiac electrization, 350 IntragaMric electrization, ef- fect.-, 431 electrodes, 3S5 Intraspinal di>ease, electricity for, 515 Intrathoracic tumors, radiog- raj)liy of, 1010 Inverse current in .r-ray tubes, 7O(i, 707 di.-diarge, 115. I 1H in radiograi)h\ , suppres- sion, sill of r-ray tubes, 7si> regi>t ration of, Mil) spark-gap.- for, 7sH ventril tubc-s for, 7Sli, 7S7 Involuntary mu.-cle, contrac- tion of, 331 lodin anaphore-ia for adc-niti-, Kill for goitcT, IOC. for- gononheal arthriti- of knee, 107 for tabetic- arthritis of knee, 107 for h\ perth\ roidi-m, >',:',, ioni/ation for acute ton.-il- liti.-. IO7 Ionic medication b\ electrol- \-i- :-;il!l. See al.-o C,il- ;,,,w._w.v. in ear diseases, 131 imlii at ions for, 11O theor\ of elect ricity, 111 loni/.al ion, bipolar, lot incipient cancer ot breast, 1O1 burns due to, 3711 b> cathode ia>-, 713 b\ radio-active .-ub-tance-, ' 1211 by ultraviold ra\-s, (175 b\ j--ra\ , '',' is conduct i\ it \- of liquid and, INDEX 1307 lonization, heat of, 205 Johnston interrupter, 727 Knee, iodin, for acute tonsillitis, 407 interruptions of, 857 fo metallic, therapeutic applica- method of immobilization, tube tion, 297 1094 in of air bv x-rav, 043 of measuring x-ray dosage, Knee-c conductivity, 043, 044 1155 See ; over earth, 5} Joint diseases, high-frequency Knifes therapeutic uses, 013 currents for, 583 doul to render conductor, 25 of gases, 012 radiography in, 1105 injuries, high-frequency cur- Knock by channel rays, 713 rents for, 583 1075 bv ultraviolet rav, 643 Joints, oxygen injections into, Kny-S by x-ray, 013, 098 1074 _ x-ra\ conductivity of, 043 rheumatism of, radiography Kodak processes for, 042 in, 1115 Kroma of salts in cells effecting stim- stiff, static wave currents for, ulation of nerve and mus- 74 cle, 331 tuberculosis of, radiography Ionized gases, electrolytic qual- in, 1120 ities of, Oil x-ray for, 1 IS!) Ions, 2 IN, 012 tumors of, radiography in, fixation of, in tissue, after 1 1 05 cataphoresis, 100 Jones' (L.) table of duration of large, produced bv x-rav, 698 condenser discharge, 390 LAC-RIN metallic, 259 test for paralysis of serratus elect migration of, static elec- niagnus, 478 Lalaiu tricity from, 55 Joule, 172, 371 I.allem negative. 043 Joule's law, 215 work reduction of, in electrolyte, Lane's 25!' put of metal electrode, passage KAISKK'S blue-light therapy, 087 I.anolu into electrolyte, 259 Kanalstrahlen, 049, 712 1144 positive, 043 Kaolin electrodes, 3.82 Large and negative, at, same dis- pads, 382 au charging point, 320 Kassabian tropical developer, Laryn^ oxidation of, in electrolyte, 890 rent 259 Kathions, 248. See also Ca- Larynx small, produced by x-ray, 09.x tions. transportation of, rate, 400 Nations, 248. See also Cations. hi velocity of, 200 Nave's halation experiments, in electrolyte, 201 793 rei in gase-, 201 Keating Hart's electrode for ful- X- Iontophoresis, chlorin, in rheu- guration, 502 dise: matoid arthritis. 41 1 fulguratton for cancer, 501 99 for sterilizing root canals of Kellev-Noett titubator, 8X3 norn teeth, 105 Keloid, electrolysis for, 418 para Machado's table of indica- galvanic current for, 427 pin i t i tions t< ir. -110 Iridoplatinu u n lie for gal- . 027 T 11 oe vanopuncture, 410 radium rays in, 1270 Iris diaphragm, 791 static electricity for, 127 In effect of r-ray on, 1 139 thio-inamin for, 027, 1170 Iritis from ultraviolet ray, 0x3 x-ray for, 027, 1 170 .r- 1 atent machine, influence of, so ution expo.-ed to radium perit 122 rays, 1 L'O.X tii soft, 1 17 Keratitis from ultraviolet ray. Int in primary coil, 1 5, 0x3 electrode amp, 007. OOx, 009 Kerato-is, high-frequency cur- La t era for electromagnets, 113 rent for, 021 og magnet i/i n g effect of dynamic X-ray, lanolin tor, 1111 plan elect!i'-it\ upon, 107 Key receptacle, 20, parti'-le- n eye, electromag- Kidney diseaser-, diathermy for, i net ic extraction, 151 "030 ' radi. voltage re niired for, 097 high-frequency current for, Isolated condenser spark.-, ap- 575 of plicatio i, 195 effect of .r-ray on. 1111 of induction .-hock.-, curve, of, ra liography of, 1019 ixs re-u t-, looo of for facial paralysis, 172 tr. len-ulo-i- of, high-fre- of for incont ineii'-c of urine, quency current tor, 5s). 129 1 1x9 of stimulation by, tx 1 radiograpln of. 1O01 of Leyden jar .-park, application, x-ray in, ! 1x9 of 190, Kici bock'- quant itometer to j scler Isolation of calorific ray- In measure x-ra;. do-age. 1 15s 51 qua'-!/ len-es 005 Kilowatt. 172 Law's L-oni'.-tnc contraction, :;10 Kilowatt-hour, 172 volt; I. -' itonic contract ion, 3 1 5 Kincte- ,-nerg\ , 171 chan It'-hing. x-ray in, 1 17s l\t:e-. anteropo-ierinr radiog- Leach'- raphy of, Hi7:; Lead b arthriti.- of, gonorrheal. iodin diapl .1 v\ys. See .U./x-V/,,. anapliore-i- for. \(\7 lejunum, radiography of, 1020 nitoro-cnpy of. 1O72 s] fellinek'- ob-ervatio,,- on dec- hydro-art hro.-i> of, faradic Leaker trical accident- 35O-305 uiTent for, 120 ilc Jelly electrolyte, 2O 1 oxygen injection- into. In, 1 . Leathe John-ton !!uoro-cope, 71o radi 'graph;, of, 1072 ray.-, Knee, radiography of, exposure for, 812 tuberculosis of, radiography in, 1 120 Knee-cap, radiography of, 1071. al>o l'ot,-ll,i. switch, 130 louble-pole connection.- in, 223 Knock-knee, radiography of, 1075 Kny-Scheerer interrupterles.s x-ray apparatus, 748 Kodak film for radiography, s()x -r's mercury vapor lamp, 072,' 074 for diseases of skin, 090 for trachoma, 090 therapeutic u>e- of, 690 INDKX Le ( ' :. he - - 11, "1 is :'..r low-ten- sion int. rrupti-el currents, I'M to te-t mu.-cular contra. - . t."i7 current-. |sv. I'll. r,_'s . devi lopinent and. I'.U ter of. 1''2 development and. l"t di-ael' ant ure - I, I'-:; . ITe. ' on rabbit-. I','! elect i . -'.2s laraeli" current und, ontn- paris in, I'.tL', I":; e-the.-ia, 5:;n it ion, ,".:;u, .".:;i liter. 1 i 1. L'.S, t'.l] low-tension in'errnpte-d r/ur- re-nt lor -i iatie-a, .".07 me tin.'! of ondo-opii' pho- totrraphy, .'.'O e-ular contract ion, 157 iti e-nt eii trijre 'i.mal neu- ralgia, .".01 Left-] mile i spiral, matrnetie' pol.-- induc.-d bv curn-nt ... |(r|li ,, lx I.et-al electrocution, 2!'.-. I.. :--. art. rie -of, inji e-teel, radi- otrraph; of, ] 127 be, we el, rail .. 107.", i .p; of, M.7.". ' . ,. LM ph - "'. 1075 |Us apparatu.-, -t'.l7 capacity of, L' :',."), 2t:{ formula, 2-1.". charuiiu.', 20, 210, 211 formula', 2 ! 1_ di.-i'harire- ot". L'i , 2S etTe-cts of, 27, W.I on blood, :;12 from statie- mae'hine, .'i 1 o.-e'iuate.ry nature-, 2H in treatment by static electricity, 12 pathologic 'effects, absence potential of, 2t:', ffirimila, 21.") shock from, 27 .- ispended, -park.- from, is t herape-utie- va'ue, 27 Li'-hen planu-, radium rays in, rube r, L'ah anic curn-nts 1'or ite-hintr of, 127 inin .-at aphore.-i.s for iti'hintr of, 11s radium in. 127(1 tie elect I i'-it \ tor, 127 1' . inn nl for, Ols .r-rn\ lor. lils Life, e . ciric th. '.ry of, 2(17 LiL'ht and In at. nnliant, lor ua I-. lisii , -7' i iron ' i eii-i hare.'. -, .".7 iandar.1 of. '..",7 o; elilT. . ni ''olor, pi-ia tratin; p patient ami sensations alter, ii.'l i ITee-l on ,-\ e, (is:{ markinjrs in, :;.".t t ii-atment. :{."ili -ray in, iL'Ki Lipmann's capillary e-lectre.m- .1.1. 171, 17.". Lipe.ma, r-ray in, 1 17tl Liquid interrupter:-, 1-15 o-i-tance tor (iailTc'- trans- te.nncr, 71 1 rheo.-tat, 2O2 \olt-contre.ller, ISl u in.- .-tains. 1 1 s Liquid.-, conductivity of, 1 sO. ,V me thod of ap- pKi'njr radiojrraidiie- ali> . Mi! i -M, Ill's me thoel, SC.S I ,->- m.-tl o.l, Miti I e-ali/e r. Mack, n/h - I >a M, l-,,n. Locolliotof ataxia. radium ill. LllIMls, clirettaL'c for, statie i-lee- Magnetic pole- induced by cur- 127x I ricit\ alter, l_'7 rent ihrouirli de\- sinusoidal run-rut tor, 1 1 1 er\ themato-U-, elect ro \ -1- in, trorsal helix, HIS static spark- for, 7:; 1 IX through loop o! win-, wave current i'ur. ">l.'i liiirh-l 'rei|ueney current lor. 10X ultraviolet ra\ I'm-, Cixx lil'.x tliroiiu'h sini.-tnir.-al vesical criso in, galvanic' radium in, 127(1 helix, ]0x current till', .11.1 -tat ir elect ricit v lor, !_'7 throiiuh spirals, ]ox, j--r:ty in, .11.1, .102, 1 I'.cJ j'-ra\ in, 1 l.M ' 10!) Lodge's theory nl' transmission FiiiM-n liuht in. 1 lx:; throiiL'h .-traitrht wire. nl electricity through gases, fulirurat ion for, ."iii2 107 lilO nicreiiry \'apor li^lit for, (ISO liv laser- of v, ire about valve tut).-, (110 radium' rays in. 1270 '-pool, 100 I.niiL'itiiiiinal rrartii.n, till uviol lamps for, lix'.i position ol, when stniiirht Loofah spnnire with compres- vi Ijiaris, iii^h-frequcney cur- wire passes under iron sinii diaphragm. 70ii rent for. (121 bar. 107 Limp of \\ ire, current tlirouirh. phototherapy for, (17(> properties of voltaic cell-, 1 |ll pnsit inn nf masr.net ie pules :n- ultraviolet ra\- tor, (17(1 rays, ii.1O (llieeil li\-, 10s z- 'ay in. 1270 reluctance, 1 1 1, 120 I.iivil>iul-( 'nrhett tintometer, Luraschi's method of i iea.-ur- unit ol, 120 1 1 .1 x ini: r-ray dosage, 1 135 riim transformer, dosed, to Low arterial tension, hiirh-tre- Lux. (i.-)7 reduce trol!e\-car current, i|uency current lor, .127 L\-mph, electric resistance of, 2 1 .1 potential wave of, 27.1. See M07 whorls about current of elec- also '<(' of m nut in- mria- I.\ inphan^ioma, electrob>is for, tricity, 1 10 tiiin. ' in; Magnetism, Ampere's theon, l-ray tubes, 70:> Lvmphatic elands, etTects of 1 1 t 're-nits from. S}|> x-ray on, 1 b'17 elect ir currents from. 1 !(> Low-ten-ion currents, death mediastinal. tubercular, x- elect ri<'it\- and. n-la'ion. H '7 from, :',(17 ray in, 1 Ixx remanent. 1 1 1 effects of, 203, 201 of neck, tuberculosis of, Mairnet ixins.' durini: flow of cur- on blood-pressure, 201 .c-ra\ in, 1 lx(i rent, 1 10 on lieart, 20 i pulmonary, fluoroscopv of, etTects in power-hoiiM--, 2H1 on respiration, 204 lOOx, loon of dvnamic electricitv, 107 tetanus from, 201 ra.lioL'ra)ili\- of, 1OOS Mairneto'cathodic rays, (1.10 unidirectional undulatorv, tuberculosis of, .r-rav in. Magneto-electric ma'dunes, 1 17 too 1 lx:,. 11 Ml, 11x7 iron core in, 1 22 interrupted currents, I.educ Lvmphosarcoma, x-rav in, MaL'iietos:rai)hs, (lox apparatus tor, 401 'lio.s l-';i:> M^Mgnetolnotlve torce, unit of Lower extremities, fluoroscopv 120 <:f. 10HX Mairni:\-ing fluoroscope, Tou- paralysis of, Ixl sey's, !<21 radiography of, lOtiS MACIIAPO'S table of indications Make -hock. etTects on heart. Lumbasro. faradisation for, .110 for iontophoresis. Ill) :;7! galvanic current tor, .10,1 Maehe unit of radium emana- Make-and-break current-, I:-',! high-treiuiencv current for, tion. 121 17 Makinir of current, contrac- .i'.i:i, ,104 Machlett's hiifh-frequency .r-ray tions at. :;:;! statie electricity for, 77 tllbes. 7li(i Malaiiuin'- transformer. 7 (('. Lumbar reirion, muscular rheu- water-cooled .r-rav tube, 7(i:-', Malingering in hysteria after matism in, salicylic cata- Mackenzie-Davidson loralizer, injun . M'M; pliore-is for. lO'.l ' S(i4 in paralysis after injiir\ . :!!ili sprains. electricity for. loll Ma.-kerel brine for chilblains. Mamaral depre. ive insanity. vertebra', radiography of , 10(17 (12(1 electricitx- for. .122 Lumen, <>.17 MacroL'lossia, elcctrol\--is in, Marble, insulating proper; i.- Lumiere Sitrma jilates for radi- 420 if, lo-s 111'. 22.1 ography, xi m Matrenhhise, HKil absor))tion of moisture liy, Luniinosit\ test in eye dis- Mafrne-ium c:ita]ihi uv-i- for tia 1 L'_'l. ea-es. :',[>'.',. .'-'.'.I I wart-, (Oil Marconi wireless telegi iph . Liinisden's method of measur- for funi-ratiim wart-, 1O(1 ,1117 ing voltage, 1'.I7 Mairnet, Hi7 Marey's dnitns, JJlfi. 3\7. :',!x Lung abscess, pleural eiTu-ion attractive force nf, 1 1 2 Mane and Hibaiifs table for and, differentiation, deflection of cathode ray by, -tero-copid radio'Tapli- x]il 1010 fiJS Marker, lead, t'nl plat.-s. xjo, x20 thirkeninir and. differ- lifting pi WOT of, 1 12 Maniui '- tri'at iiH-nl for inc. ,n- entiation, HUH p.. i - of, 107 tinelire I ' lirille. 12'.' pneumothorax and, differ- rintr. do-ed, transformers Marmw, effect of j'-rav on. entiation, lOO'.l and, 120 1 IM'i. 11.-17, 1 1 12 radioirraphy of, loo'.i Magnetic effect of discharges. Masking of wave ot n-gative ape\ i>i, tuberculosis of, lull .-|."i. .'ill variation by superposition, diseases, costal aiiL'le and. :: 1, separation of radium 27 x 1 00 1 ravs In. 1211 Massaire and radiant heat for hinh-friiiurni'y current 1' ir. l!ux, 1 1.1, 1 I' 1 cicatrices of war wound-. r,( 17 id linition, 120 llxii eti)|i\ ema of, radii nrraphv i if, direct ion i if line-, 1 1 i auditory. Ixll l(ii:i fonuula of, 120 electric, in rhi umati-m, (102 flllor pv of, 'l'n; measurement of, 121 vibrator for. (1O2 bodies in, railiimraphy i ,f -; , p-di i-,\ n ' : : ; n c inj 11 ies, 17,1. :.12 ;:., 101.1 ]>,:, in - i a t i i i , .110 1\ n.pliat ics of, fluoroscopx of. ui it of, 120 i tro Ii . i:; IllOx, llHI'l in. rtia. 1 1 1 static, for iii'iirastKenia. 121 radio!'raph\ of. IIIH-N i lie. a-tatic, 17:; MUSS, X '- method of ,:. ntdiuirrapliy of, H'.i'.i, lnn2 elTects ol ,lynaii;ic elee- ralai- hor.-i-, (O2 . loir, .ln7 Ma-toid cells. radioL-ra] die; 1, test of, '.MIT, 17:; on; tumor- '. : rraph; (u mi ' .\. 121 M a s i i d i i . . '.:_'. HUD p -, ui t, 171 it for, os,, Lupus, blue-liirht treatmeti! determinat ii .n, mnemonic Maxilhe. tist il L- ': :;, for, i' P x7 mi thud, lo'.t cataphor,-i- for, lo.l INDEX Maxillrr. fistulas and necro-is of. Mercury vapor lijrht for tuber- Milliampen- and hack-up in .-- ipliy of, 1147, 'Ms culosis, larymieal. Coolidtze tube with un- ' ..-: p\ "f. !Mti til 17. tills, tiss' changed filament incan- int. rii -: . fracture of, radiotr- pulmonarv, (il)7. tins descence, relation be- tapln in. '.' Is local effects," (is!) tween, sir, radioLTaphy of, '.ui., therapeutic u-es. tis'.i in a jras-filled tube with un- r;i -is nf, rai [ii _:-.; '!iv ..f, vacuum tub-- as double- changed vacuum, rela- ''17. '.'Is current rectifier, llil tion between, Mil - i- 'ina >:'. .."-ra;. in. 1-'M_> Mc-othorium. l_'7s Milliamperemeter. Ill), 144. KM Maxillar\ -inu-. radio!.'raph\ "f. cost of, ll_'7il d'Arsonval. K.H' '7i 1. ''sj . See a!-> > .1 '.-. electroscope test of. 1L>7'I dead-heat. 14 t. K:< ... lor uterine cancer, IL.'7'J hot-uire, l.'i-l. still Max. ii.ua/ > fli.'-ienc-y, calcula- for fihromyoma, iLMMt for mea.-urinn intensity of tii ''i. s7 Metabolism,' defective. hinh- alternating: current , _'l) law . if, s7 ivequeiicy current lor, ,~i7."> to measure .-treiiirth of sec- troma^'iiets. n 1 eftect of r-ra\- on. 1 1: J ,II ondar\ current, 1-">M M i mly's tratisp. Ivic lin.- for M.-taearpal bone-, supernu- Use of. 11 t'l hip displacements, In7'i merary, K)'.i7. Hl'.is Minin lamp, tis7 M ; '-h p.'K .-in.- generator, Mi-taearpu-, fracture of, radi- Mirror L r al\ anometer, Thomp- ; m ography in. 1100 son's. I'.KI M .-I. -. - ; .._'. f. r. tisf, radioL'raiihv of, lll'.i:-! slereo-cojie. Fifeon'-. Sl7 Me i- .-- mi nts, < '. I .. S. system, TOUSCN-'S method, 1101 Mixinu battery fluids. ])recati- |s tiiherculosi- of, radio^rapl.\- t ions, '.d trie, is in, llL'd Mm-monic tliairrams of direc- ..I v, I--- in of .r-ray. 714 Metal, acid-provintr of. 21o tion of currents inducinn M- .-.'".ru insulation re-istaii'-.- backin" for plate-, spi north and south magnetic : : .'.'._'!_' ball, insulated, inside hollow 1 10 arity, Hl'.l M- : - . livalent of elec- n eta! sphere. -MM. LM4 Modern static machine, :i(). See , ity, !_'.; i-onduction through. L'."i.s also Xtufir nuK-fiiii' . .:.' rr inters, 1 H. s.-, } electrodes for hiL'li-frequenc\- -toraL'i-hatter\-, 100 ndensers for, s.',7 work. .!,:'-. .-f,4 Moi.-tuie. absorption of, b\- iral force.-, -tat!'- rlec- for recta! diseases, f.14 marble, L'L'f. . . from, ,">4 uses, iist ). :-;sl static machine and. 41 fee' it'n-r lor alternating cur- electrons, velocity', L'lil j--rav jilates and. .s'.Cj ::.'-. in." figure.- for luarkiiiL' plate-. Molars, radiography of, '.150, rru]>li% of, IMSO Moon vai mini litrht. (\:>2, o."M '.:-: .-. .-- i\ fib.-. 70:; Metol hycirinnimone developer, Mn, m '.- method of ondoscoj.ic .' in. !:>: ss] photography, ,'.'() is, . tnpha.-e baths m. Metric measures, J-lnulish equiv- Moriix s orthoradioprapln oi . : - alent-. _'_'s heart, !(l(i7 . ;' :- ir, 1M 1 M. n 'Home interrupters for Morjihea, galvanic cvirn itz-1 :. for, timini: rn\oirraph. Mis, :-;p.i l.'ii '. 17 Metro- : '. ijiia, i i(fh-ln -ta1 ic e!i ctricit v for. -t_'7 M- Mai di-ord. i>, i i. "trii .1;. for, current for, ,"s^ Morpliin, n.-rvou's c'ondudibil- "_'_' Ml, ., is] it\ and. ::;_' fora n. en in I tio|_'raph oi Mi'-a [) ate- lor stai ic machine, .Mor.-e's suiL'inu ' le'-tric appaia- . . -.1.-, M7 tus. IMC ' ! -.- -.-. ciiia, i- Mi- mil .later, l.'l Morton mi -hod . ,f seiisibi'.i/inn /. 1 _'<,'. M -,- ..i. r.-'. 17.' i i.-.-iies to licht. lisL' - 1 - , 1 1 I I 1 1 f e 1 e c - \\-\- e ] Tre 1 T 1 ' i "-' e 'd-O . !0-J ' . -.-.-. 1',.; . :. .:.. on, !_'."'' . - - tube in epithelioma. . on, 1 1 MM IJJ.'i - - - - s.',li \lidd!.-.-ar' di-ea-e. catapliore- \1; ti area of brain, '] -truction . 7 _'7 in.", A eil 1 lo- - |,i, - 7 _' ! - ! --:' loc ,] , !, ,-trii aiie.- evitabiliu , Mil.' . . . :--: cen-il-, diseases of, 170 irrent ;or, .Mill spinal paralysis of. Is] . ranial nerves.'dis, a 1. I7n 7_'.i, - ",i , ;,,, -, . ,,-, tit'.. ibanci 7 J. ' in. 1 \'M ' 1. ctricii\ for. IMd '.'--- ' - . -.-... ..... . ...... . . -7'i I - : 1 1 o ! : - , .Vi j.neumoL'astric ' 1 , -'-'M . Ml'' ' ''",,' M ----. I'M. M - - " ' on MI MI ".- .- . . . -. n on , ,-lric. ! _'ll INDEX 1311 Motor generators for Gaiffe's transformer, 743 for r-ray work, alternating current, 740 direct current, 7.~>0 to reduce trulley-car cur- rent, 21."> nerves, degeneration of, elec- trodiaunosis, 3'J1, 392 excitability of, 312 of lower ext remit v, paral- ysis of, IS1 of upper extremity, paraly- sis of, t77 peripheral, diseases of, 470 paths, diseases of, electricitv for, 51 4 points, 335. :iS(i value of, in testing muscu- lar apparatus, 458 polyphase, 127, I'M reactions in diagnosis of pe- ripheral diseases, 455 voltaic cells as power. 205 Mottling during development, 890, 891 Mounting; prints, SS4 Mouth diseases, high-frequency current for, 015 radiography of, endodiascope for. 771 ' radiotherapy of, endodia- scope for. 772 .r-rny tube for, 771 Moving train, telegraphing from. 13:5 M. Q. developer. SSI Mucous membranes, currents of rest in, 271 effects of high-frequency applications to, 509 electrodes for, 382 Miiller water-cooled .r-rav tube, 703 Multiple galvanopuncture, 41(i neuritis, Schmidt treatment for. 502 sclerosis, electricity for, .".14 spark-traps, 701, 7M> Muscarin, effect on cardiac stimulation, 352 Muscle, current of action of, 273 of rest, in 271 effect of electricity on, 302 elongation of, reflex, .'i 17 normal, tonus rhvthms in, 345 paralyzed, extensibility of, 333 static induced current for, .', 1 3 polarization of, 27."> reflex elongation of, 347 relaxation of, in stimulation of nerves of animals, 317 voluntary, absence of inhib- itory nerves in. 340 wave 'if negative variation in, 271. 270, 27!". 330, 331 Mu-cular adhesions, static wave currents for, 7 1 atom . -tat ic spark for, 73 atrophy, chronic progressive, bulbar paralysis in. 170 fr.ur-cell bath for. 115 progressive, electricity for, 51 1 abnormal', "3'Jl' " after death, 31 1 atmdal closure, 331 opening, 331 :;t breaking < <\ constant cur- rent. 331 at closure of con-taut cur- rent. 33] by condenser discharges, ls.5 Muscular contraction by d'Ar- sonval transformer, 509, 570 bv elect romechanotherapv, ' 4 S3 bv high-frequency current, ' .509, 570 bv isolated induction ' shocks, 484 bv monopolar stimulation, ' 33 1 , 335 bv peripolar stimulation, ' 338 by tripolar stimulation, 338 cathodal opening, 331 cold and, 311 curare to prevent, 314 currents of action during, 327 d'Arsonval's method, 344 Delherm's apparatus, 487 designations, 331 differences in electric con- ditions and, 331 Du Bois-Revmond's law of, 334 furadic, 4S."> and galvanic combined, 4S5 anomalies of, till current in testing, 459 in myasthenia, 3!)5 modifications in effect, 47 faradogalvanic, 4s5 fatigue and, 333 _ from condenser- in parallel with galvanic currents, 311 of larger capacity parallel to patient. 391 from drugs. 315 from rapidly repeated con- denser discharges, 311 from series of stimuli, 330 from stimulation, 313 Oaiffe's apparatu.- for, 4S7 galvanic, 400. 1st anomalies of, 401 heat and, 313 height of, 335 hysteric, faradic current ' for, 4S3 in degenerated muscle, 3,45 in disease, 457 in striated muscle. 32S after death, 31 t siibmaximal. 337 in unstriared mu-cle, 3,2S inhibition of, apparent, 315 isometric, 3 Hi i-otonic, 315 latent period of, 321 registering. 321, 322, 329. 3:-i() laws of, 331, 3Mi F.educ, I'.c; beL'innintr of reaction, t'.M table for mensural ion of, 157 longitudinal reaction, lii! maHngeriii!.' and, 3!)ti MareyV drums to study, 317 maximal. 335. 33ij nien.-uration of, 157 motor point.- for. 335, 3Si;. 15s nature of current tor, 33'. i o! int-iL'oni-t ic muscle-, 3 17 of muscle -epatated fn/m body, 341 o-motic pri's-urc dunii!:. 334 I'fliiu'erV laws of, 3S6 Muscular contraction, points of election for, 335, .'{Mi polar, nature of, :',2S (juality of, in disease, KK) (Hiantity of, in di.-ease, 400 refractory period of, 321, 322, 320 resi.-tance and, 333 serial, 330 sluggish, diagnosis from, 3!tl stimulation of, by -ingle condenser discharge, 310 of nerve and, 334 therapeutically, 483 strength of, 335' submaximal, 337 temperature and, 332 testing of, 450, 457, 458 tetanus and, 33li therapeutic production of, 4 S3 threshold of, 335 tonic, 345 Tousey's method of test- ing,' 458. 45!) wave of, 330, 334 galvanic, 273 with alternating current, 344 with faradic coil. 100 currents, registering of, 322 Tchiriev's observations, 2s!) pains, acute, static >parks for, 73 mild, static breeze for, 73 rheumatism, incandescent lamps for, 001 salicylic cataphoresis for, 409 sinusoidal currents for, 441 Musculature, effects of .-tatie electricity oil. 71 M iisculocutaneous neuralgia, electricity for. 501 Musculospiral paralysis. 47!' Mya.-theniu, electrodiagno-is of, 3! 15 gravis, 470 reaction in, 403 Mycosis fungoides. galvanic current for, 427 x-ray in, Ils3, 1233 Myeliti.-, electricity for, 515 Myeloid gumma of bone, radi- ography in, 1 110 Myocardium, effect of stimula- tion. 352 Myograph, 315 chart- of, 320. 342 effect of speed of paper upon, 321 of temperature on, 342 Deprez electric signal for timiiiL', 31s. 3111. :>,-2(\ 321 for reL'i.-terint: isometric con- tractions. 315 isotonic contractions, 315 Herintr's double. 32s pendulum interrupter for tmiini:. 3,1s timing mechanism for, ols 1 to register elei'trometric cur- rents. 32(1 latent period, 321. 322, 329, 330 tuninir-fork for tiii.inir. 31s, Myographic c\irves, 2so Myositis, high-frequency cur- rent for, 50) Mvotonic reaction. 3!i3, I 1 ''-' Myxedema, d'Arsoi.v:! .'.:: ut 1312 INDKX X \'.l 1.7.1 !!\H!' r's Illlt Ilden- Xrrvrs, anlrrior crural, paral- Xer\-e, sensory, react ion of, 40-1. -at 1' ill ..'. !,. i '..;:; yr.is ..;. 1-1 Sec a!-o .-' ;, -..// ni-rnx. effect on wave .if as I'orcil rondurtor in i-lcc- sixth, involvement of, in live V.'ll iat 1. .Ii. J-.ll trotonn.-, J\.") facial paralysis, -17-1 l.i" ..: nervou- conductibilit v auditory, react ion of, -lo'J spma 1 acce.-.-orv, paral\>i.- of, . .: u ci-rvicai >\ nipatiiet ic, -I iin- 17.", Xa.-al deviations, cle.-troh -is ulation of, :-!ls, :{t'. s]ilanchnic, stimulation ol, inr. It'.' condenser di.-charne llirouirh. ira-tric effect-, :{.-,() poh 1.1. . Icctroh >is fur, ll'.i .'ill', i stimulation ot. See Xtimtiln- .- ; LIIII, .1. . :::' inn.- in, cor- conductivitv of, effect of cold li'ili, IK 1 inns. rected by regulation i.f on, :;!! ulnar. paraly-i.- of, -1x0 i-th, '"._' electrotonus and, Js \ vapus, parai.\.-i.- of, -171 radii .L r raph v .if, '.e-7 lo-r- ot, from narcotic-, iilJ \\ave of ne^a!i\e \ariation -pur-, electro'ly.-is tor, ll'.l in ane-the.-ia, :11J in, J7ti, J7S National Board aUie- of, -170 elTe.-t of narcotics on, <-:ipa. it\ i)l '.'. ire>, JJJ current of action of, J7o L'-O \ tin il Miurces of .-tatic elec- current:- produced by cold fatigue and, 2SO : . i ' . .",i applied to, :{J^ Xervo-st retching for .-ciati.-a, X'e.-k broken from diving, of re-t in, J71 r,io radiography ot, ov.i fffccts of electricity on, :i()l Xer\'ou- di-ease-, treneral, elec- rail. -IT of, radiography of, excit;i'hilit\- of, after tran trieity for, ."il'.l 'I'l.". plantation, :-;ti hicli-freijuenc\- current for, fluoroscopy of, 'J-s at dilTerent part^, old 5S7 i' .n iirn In ulie.s in, radiog- cold and, :',i:i radium in, 127s raphy of, '..111 clcctrotonus and, J-:i, J-l di-oider- from pol\ plia.-e cur- lymphatic- ol . t iiberculo-is fati(llf and. :>,\:>, rent.-, i:',i of, j--ra\ in. 11 si; heat and, Ml:! .-inu-oidal current^ for. 111 . : : iniir, fracture of. radiog- traction and. :m dyspepsia, headache in, gal- raph;, in, luiis <-xhai;-tion, in'hicnce of cold vanic curn-nt for. ."ijti iinunitcd, radiography on, :',\\ symptoms from s-r;i\, 11 Us of, 107J facial, paralysis of, 17J. Sen system, disea-c-s of, elect ricitv of uterii.-, cancer of, cata- also Fncinl n.rn, pnrnl- for, l.V), .'.1 1 phore-is for, in) .'/"(' ".' effect- of electromagnets radiography of, !ls'l Miinulation of, for drv on. I.',! .r of, i idiojrrui)hy of. ( .i'i.~ otitis media, 1M1 of jr-r:i\- on, 1 1 10 Xecro-i- and li-tula of ja\v, t nmk ot, .-timulation, o->. of power-house operative-, irraphy of, '.H, , '.Us CU.-tator\-, react ion of, 170 Jlti coagulation, in clc'-t ro';, .-i-. hypof.'10-.Val, paraly.-is of, 4.V) peripheral, di.-ease- of, eli'f- J' . 1 7 inhibitory, ab.-ence ol, in trodiagnosi.-, 1 .").") of 1, :.. . radiography in, 1 107 voluntar\- tnusr-les., .". 1H Xeuralgia, blue-light bath.- in, of juw. radiography of, '.Ho, Latent period of, effect of (is7 lit 7 alternating current and, brachial, e!ectricit\- for, .">0ii of t....tli, radiographv of, '.117, '.MO cataphoretic cocainizat ion '.Us median, paralysis of, -!-0 for, 10."> X'ecro-perrnia from .r-rav, 1 !:.,, stimulation ol, :',s(i eer\-icobr;ichial, ."ilMl. See 1 l.Js motor, exfitability of, varia- al-o Crrrirobwhi'il ln- Needle, bulbou pointed, for tion.- in, '.', 1 J r'll'iia. . Ii tr.il.\ -i.-, ll'i ol lower extremitv, paral- cutaneous tenderne-- in, ."iOl .!<. 'trod.-', :ivi VMS of, 1-1 deltoid, .".or, i . . inopiiri'-turo, :-j^:', ot" ujipi-r extremitv, i>aral- diathermy for, C,:',s . 17.; y-i- of. 177 electriciu tor, ."ill! rli-viation. in. I'.tO peripheral, diseases of, 170 facial, el.'-ctricity tor, r,01, .",0.", -. !:< obturator, parak .-i.- of, 1-.1 glass vacuum electrodes X. L' ltiv<- cll-r-tri-'iTy, Is. 10, J.!!', ocular, jiara v.-is. '.ii') oji! I.-, no -i-n-at ion of li_'ht in liigh-tre'iuenc\- current for, . , x ^. ^ e]. I-T ri' 1 -t im ulat ion of. .)7(l ."i'i:{ :,'i.'- -'<-', incande-cent lamp for, Cii',1 .-. ntuatc fr-a- arrophy of, hiLdi-fre<|ueni'.\- illterc.i-tal, eleclricit\- for, ."i07 1 :,'. - ''7'' curn-nt tor, (i 1 - rn-rvi- blocking in, Js.', - froi r-ray, 1111 elTect ol s-r:i\ on, 1 1M' iieuriti- and, dilTerent iat ion. . . radiography in, .. ict ion of, I'i- :.' 1 1 I in, ; j/hj.-hi.'. -i imul.'ii ion of, i'.Mi Of te-ti-, :,11 - -''. '''' ''''' . lor i-|.|i irolorm -;. ncope, 1 J' t ).' !. ic, in iieura-t hc-tiia, iii- duced ciii'reijt tor ->J1 .,J., . plantar. ] ir.-i] -i- of, 1-J railium ra\ - in. do-age, ] jr,." . '7 pneumot'a-tric, fal\ aiiic cur- referred pains in, .",()! ' rent lo, in L':I -i ric rii-- -'la ' 1C, .",( l7. See a !-l . .-' tlltirfl . . i:: nHiralt'ia, .-;: -. - . l.'.l static induced current lor, 71 lion of, cITect on -park for, .Mi:; tion of, -tudn- heart. :;"iJ Ihermopenctrat ion for, '>'<> va-omotoi c!T.-ct- on t : i' r cn i i na 1 ."i ( 1 1 .V )'' >i .- a l-o . u inte-t me, :; I'l 7 . ' . i/ . inil'ii'i. / ' i' .n o! , J7."i \ i,ceral di-iuibanc,.- and, 7,01 ',, .;.;! i- ol. 1-| .. "i-. eMimination oi teeth i: . . re||, x -Mm ilation ol, :;io in'. .'iHJ ','.] !.;' j--ra; for, '.'..; , . '', Xeura-lhi nia, abdominal, elec- tot tricit lor, .'ij.'i 1. :;).', Alpii,.- '- ra\ing for, c,!il of, 1-1 i,|.,...| ,,.. -UN in. :,JJ .' : ' ' . ' n .-'" va.-o- c.-rebral, gal-, anic cm ier,t tor. d'Arsonval current for, :,_>o d\.-pep-ia in, liiKh-frriiuriu cunvn! for, o-'7 it v fcir, .ii':; laradic current lor, .")_'! galvanic current for, .~>l>."> cephalir,.-,:.'l> impotence in, o-o Neiiro.-e-. occupation, elec- I ricit v for, "ill i Neiiro>thenia, .V.M) Neurotonic n-:n-tion, liiii Nculr.-il win- of electric-Unlit r-ervice, _'n7 i-urrent for, ">!' ! piiciinii>L':i>tric n;ilv:iniz;il io for, .li'il .-inu-oiilal currents for, I I 1 static l>:ith for, ">L':i luve/j' tor, .'>L':i electricity for, .")_'; friction tor, .">24 inilii'-eil current for, "i- I itir-uiut ion for, ")2:i ni:iss:ijc for, .">2 1 spark for, o.'l urine in, o_'_' in, l-'i:, Niton, 1L'.-,1 atomic theory of, 1 _'.M Nitrates from iitniospheric air, means of olitaininu, "is r-ynthetic maniifact ure of, .">7 Nitric acid a> electrolyte, '.'!_ from stal ic (ii-cliarj.'!'. ~>7 ton. i' of. liot i'Xcn-1 ion. jr-ray and, 1 l.->'i Nitn.iren-fillcd 'electric H-lit Nil r-. . Ken tulie rcpuluti >r, , li'.i tests of, by Mutscheller, "(5(1 .r-niy tube, 7*'^ Nitron.- acid from ultraviolet ( ihmic resistance, ")'.> electricity lo-t liy, -'Hi of voltaic cell, !M| ( )!d grains, x-ray in, ll'M ( Heat.' of mercur\ , raduim- i I'K cran in pn icess oi ulna, fi ic- ture of, radioj:ra]iliy in, ln'.i'. I ilfactor, centers of brain, elee- tric -timulation of. :;.",:; ( indotneter, Kerri<>'s,' o!7 ()n.lo>cop ( ., 7!H). .-,^a;-.-" - , -i 'i-is it. ..,:( tre- ' '-. di-ea-e- oi central rier- ie \\ ave cur- ! ' >r, i'<_'l - ten,, electricity for, \ ! -. l^'lll .'.I i h- in. HS N . oi , , 11 ii i . \, ,,, -,,: . I irtl - ' . "'.'7 <' mea-u:-e'>i/e ol heart, Ino7 X n i rit ion, 1 ./--!!> for, :>.W 1") N . . , ' ;... Lralvanii 1 i'U r rent in I"-t itiL*. ' 'Hi -I rv. I ' rironie'- tn itn te-tinir, I." 1 -. l.V.i - I . lie, loo [i ' - . it ion in, maintenance of, 31 ! complete. :;il , I, pie. ,;il v; t'rtl ii.hot.iLn-aph; , : it i Moritz'-. lon7 . :j- Kii d, r'-. loos ' ' ' ' . ' : : : p. ... HIM INPF.X (i-:. -:-, J."i 1 .'-.: rapln in, . j-r;i '. : : . 1 _'-> x ' " : : " :. ( P\ ill liijih-I'r('(]U<'ii'-y rurrcp.t for, .V.I}, .")!C), .V.'li I'alutt . luird, i';iitlif!i(iliiH "f, .r-ru\ in, iL'l.'i Milt, p;ir:i!\M- uf, 171 i '. '.- ii clinic fin j-rav in . :: : ,:'. iLM ii Pap !. !,r.,iiiio lailiun, for, 1J7 1 I'aqui : - liiini fin !.!:!' inc .-men ful::t(jr, Ttil Pi'.rtiholii' rctici tor, (i.">!l i ' 1:1 i!i -' '.' ' Ii '. cli 'Mni: tank. ftcr ii ' . h\>tcri;j ii. ii; injrci inp in, --i' 1 !) aL'itan-, liit'h-l'rcijucncy cur- n n' lor. .V.il }' '.-, clcdii it- in, 172, 17:; Diii'lii tin. i rh's, 17-, 17(1 . . . tricin i''. 1 .')."> 1. '}'-. !7s, 17!) : !. .-tatic .: :;\ i curn ii; for, 17:; : nadic ( nil for. K'.O Irol : ::';:-. \~~>, 17o -.nil : :.. 17c. . ; - -i, and, dif- ;. :, ntiatioii, 170 .::. I'or, ntci r ci iial, 1^1 : . I 7 > i . 170 dir.jihriit'ii . radiotrr; : 1 I'll 1 :.. 172. Si c :v . / I ..'. 1315 Paraly-i-of infraspin.ltus, ITS of fan MX, I7t nl lower extremity, !sl nl median nerve, 'so 111 motor niTYC- lit lo-Aef CX- Uemities, isl i if upper exl remity, -177 t obturator n,. rv, ._ |s'l 111 ocular nerv-, ! . 1 electricity in, 171 .it peroneal, 1*1 ot popliteal nerves, Isl n!' sciatic nerve, Isl .if serratus ma-mus, !7s . : -i\th nerve, 171 of soft palate, 17! nt' sphincter ani, hitdi-fre- i lueliey curret:! for. olM 1 1| .jiituil accessory nerve, 17") motor centers, IN! nl' -ternoma.-toid, 177 nt siipraspinatus, 17s u! thinl nerve, 171 of trapey.iu-, 177 ut ulnar nerve, IM) , ; ipper i-xtremily. -177 cil va<.MIs. nel ve, 171 i rtranie, -I7ii funct lonal paralysis and, differentiation, I7ii plantar, >s2 lobulbar, in:;. 17>i respiratory, from alternating currents, M7M from hiL'h-ten-ion current, sinu-oidal current- for, -1 11 slow sinusoidal current for, 1 ID Paralyzed muscle, exercise of, I>v stal ic induced .-park-, .VIM extensibility of, MMM from \\ar injuries, liipolar static inducto-resonator efiluve for, 7ti Pal Liiiafriu ti substances, 121, 122 Paraplegia, electricity for, ">!."> Par!.in-on's disease, atit duetion for, ."."1 Pa-tinn storage-battery, 10(1, 101 Patella, dislocation of, radiop- raph\ of, ID, :, fracture of, radiography of, K)7! f, 1074 !i x after lic;hi iiii,<_'-st rok<-, :):,! late appearance of, electric ':,.; I , Pe:i"U in oy>ter<, radio_-rapliy i :. 1 i:-;o , . . . ; . . .. . . , of, for chlon ili inn s\ neope, 42! i Pi d incul.-.tcd warts, electrolysis f i ' . 1 1 ! I Peltier':- cro-s, 2'i! Pelvic hones, radiography of, Kit Hi , I ,',::. h; ... I statie , : tor, 7! C'XtH late.-, lii!_'!i-i i ". lueney cur- : . . .'.'/;.::. i , i . : -'..- : u>, : . vapor li^ht i' : ' f. 1(117 radiniri ip . ni, 1017, Hi'iii in ir, M2 PI :i.p!ii . Peni-, ejiit helioina of, .r-r:r. in, 1217 Percutaneous eli-c' ri/at ion in Perforatin;; nicer of loot, faradie curn nt for, J27 liit'li-freinienev r-nrrenl in. I IM; Perincphritis, r!iirraphy in, 1 i n i: ; Periostea! piinnia, radiography in ! I 10 Perio-ti! i-, hiuh-fri'iiuen. radionrapliy in, 1 10s .r-rax for, liljij Periphi'i"! 1 nioti 'f ic rve-, di. eases of, !7O ncv\,' trans])!antatiori, excita- bility after, :;io Ui'tiriti's, alcoholic, i lectro- diaL'iio-is in, :'}'.>'> .-en-orv nerve-, diseases of, 170 PC ripe ilar -t imulat ion, M:is Perisiaisi-. hitrh-ft >' :;i-'iicy cur- rent for, "i71 llation of, before .c-ra\ exam- ination of. 101s Peritonii i-. t ul ii : cular, r-ray in, 1 iss Perinaneiit teeth, r:idio::r:iphic inea-iureiiiont bffort- c ni|i- i i. ''., o.-,.- Pernicious anemia, clijihtiieria ant itoxin in, I I'.is x-ray in, ll!s Pcroneai paralysis, Is] Perspective in dental radioir- iy. il.Vi, !ll)4 Per>pira'ioii. effect on plate-, SI!), VI2 from c-oi :ir:il stitnulat i> in. '.'> 10 PliaL'i'dcpic cliancrc, cocain eat- iresis in. till corro-ivc' -ublimate cata- piioresis ill, 1 1!' Phalitnire- ol :'.,.'. I.- : ... ni, :-.. in, IDS.', ,. ].;. of, 1H- radii iL'raph\ .it. 1 1O2 radi i : f. !': : .-. .,..-. I'iil'eb ' i'.-r for, lor.s . : ..r !' : mi.L'i-ap'h : .- .: ifn. --. 1 si I . -To Pin.-],: ' ' . . : " -ur, -. l.'Ms Pi . . ' - ' ..-. i'. I ! i -in ' . . '.': '' of l.cyd ..17 Photometer irrease-spot, Oo8 Phototherapy, ll.V) I'.i ri"i:in'-'- act mometer in, i ir.T colored screen.-, for, Wr, disea-e- benefited In , Uss L'esI ion, '.7, t. .1 kin diseases, !L'S, r,7r, for -mall-pox, o7'i. i;si; physiologic etfects, .,77 prmcipli - of, r,,o liM Phrenic nerve, stimulation of, MS.', for chloroform syncope, 1 L" ' Phy-ica! reconstruction after vVar injuries, -lol Pli; , .i,l. .trie ellects, secondary, ol .!; itherm;, . M\ of ele.-i i-i' ity, _".':-', '< i~i density of current and, Ml 12 rela ; " .n of ampcrat-'c to, " nttanl arc Ian, p. l,l,!l electroscope, I-".:, !.-. ] ii-rstal ic tran.-foriner, 70, ' .' ; 7 ion i.i ( i,",rl ultra- violc t lamp, i;7D : Ti -la apjiaratus, .Vj] PIL'I mi's mirror stereoscope, s]7, vis HS .r-ra\ for. 11s Pin is: i -si ] iliajiiis, !I'.)M in larynx, localizal : m, ! |l| l I':- In les in jilatc-. V'l m radioirraiihs, s7 j Pifchbli tide, radiui i:.. 121!) : . itraction of, b\ Ii - .1 bin i \ , 21 1 . i ir- of, radi- h tli, Muoro, 'iijiy ,.'. ol'. 1 'lam ' '- t. ''I.i, v f. if faradie ciir- renl ' Intrt hro-i.- : knee, P' mi ir pa 1 d\ -:-. 'sj PI - (,' ~ : - ; i-i. ; . -batti rv, W Plant -. u'rn nt s of a :. in, 2s] : t of bet ra\> Iron ra- on. 12110 - idii-.in on, 12HO ... . '. . | _'. ,M ' -.:..!!.._ electricity ill, ." I. _V>, , J'N : !.' - . : i :-. . ',, . ss. 1 , . si.', aluminum cas-i tt< s : r, s]ei Int. I. in r thiirl . 1072 lentil ition i.l, sjo :d, s,.7 .;, >!)7 - .;' lie fur, si '' . : . ; ir ii|enti;ic.-it i m. -._. in hind, Ms II, n intact u il li. sit .sp.i I . sill I i-! -nil -.1 inn n, ark- mi, sl'.i, MT:ifli-lii:irks nn, s'.rj - :iml. M'l |)i-i-,l.i!,c,)lii- ;,,> : vith nlh.T p!:,T,.s n . !i -. -I ! :. in's treatment. ". 1^ : i nil'. Snow's lliethml, ol.'j electricity for, .'.11. .".1 I ], ::;:!;,-:-' from. 17.'). 17'i :ilisnrj)1 inn of, 1 -'< 1 Polyu-.-tlii-ioscoiH' ot Arriiro . [i:i-:.!,i !i ctroly-isfni, H!> I', ..... , Mclnto>h, I'll' I'nij-, !. -; -n \', 11 li'tti, fai'ial p-ira!- : . - . . i 7 ! I'llphn of, ;M I'niv,.l ;; ii, iii^!i!at..r-, re i>1;uice ni, --' i gradient, 1M ni l.eydi n jars, '21.', ' ' forniiila, LM.*) unit nt. -I'.i I'oteiitiometer, I'.'.'i, ll'ii I'litt'.- di>ea>e, r:ulioi;r:ipliy in. 101(1 fracture of lihula, radiosrra- pli\ in. Hl7- 1 i:;:; I'reL'iiant cat, radiof-'raph of, 1 1:11 Preiiiycoj-i-, j--ray in, 1233 Pressure, nerve-fibers of, Inn arcuiL' in. 7;i 1 condenser for, 7:11 variable self-inductance in, 7.SH .-nf:-iron cure in, 1 .")7 inriii. lilt inti rrupt ion in, rate i >', in- on i|uantit\- of j-ra\ produced. ! H',i iiatun' of, I.V., l.'.ii. i:,7 ,,1 induction-coil.-, [011- ileiiM-r> for, L':; 1 ' elleet dl cnndeii-er on. ; it. . ssi ! -,,! -n trie p. I.. i, sx] ... i ss| ! ',(, e, II, 'HI |. ..... . .... ,|i,_ . . . : ... ss| . ....;.., on. ss| tional an^le in. IDI I healed, radiography nf, IDI 1 heart in, IDI I ill 17. I is'i merriiry vapor li<_'ht fur, 1107, r.i IS, li.s.s of apex, IDI I radionrtpln in, KID], ItKWi, ; Kudiatoi i . pe of ( 'oolidtre tube, '1 1 idio-a'-tiv.. solution, I-'.--' H e-, !_'.;'!, !_'.",_' I'll etrie ehar<:e of, I _M 1 ioni/m el-feet- of, ] _'1| properties of, 1_MD i|iiant ital ire (e~t . I _M 1 radiation from, 1 -' 1 1 water, i _'.;,D In- to measure, 1 Jll internal -trurturc of earth and. Ul:; . merit, !_'!! ' tion i-hamber, li'ls in paral ive, in l.'H, n! radiun . \~SV.I test lor, IJil :. 1J.",7 liiiih-frcn.ncticy i-ur- ri-nl : >r, iil:{ f-ru\ for, ! . ' from hydro-rlci-trii- l>atli: . I M : rei [Hcncy i-iiri > :.' >t;i: ii- l.ath for. 7:1 radium rays for, l-7_ (^uantitonii-ti-r to ini' Imlhar paralysis, Hi.'i, 17'. I'-, uiloli ilk. ini.'i, .r-ra\ in. 1 HIS, IL'IIJ . ,r. 51.-i ri-fn : , i-iii-- _' s ii i - in, ]L':H t ri ' : . _'i : 17", lilt! ; . s|7, sl> n,l N -, . . s ..; . - . : "_> o! '-. 1 n. : 1318 IXDKX . s _' 1 irreiil ' - s ; [ .-;-.- - . |,. : ,-,;:, S 1 1 . I iuli t -current tor, 711 pi . : ; . 7 7 1 . 7 7 _' .- -ur. n. Ml, s.l :.-. io.;o in an ; : ,:". . KUII ton . 1 l_'s in :-:,- ' -. izoiiorrhea!, Ills hypern - hie, 1117 : .-' . i! .,;. 1 1 1.', 1117 in '.:'. t.'ll l."j iti-n . 1 1 Hi in b -:.' ill-,-:.-.-. 1 1 1-- tumor-, 1 HI:, in l)ov.-li L--. 1111. 11 I.". ; - - , r ,, Ml|| i-i.-, HI].-, in bur-Mn<_' fi turi t ic valm . '-'o7 in i '.-te, i-an hrii is, 1117 in oMeomyeliti.-, 1 1 o7 in perforation of ,-\ ,-ball. ("Ill in perinephriti>. lor,:; in pi rii i>teai minima, 1 1 HI in perio-titi.-, 1 los in pneuni:! ' ic sinu.-es of face, iliamn --; i \ nine, '.'lid in imeiiinonia. loll in postmortems, 1 1 2s in I'ott's di.-ea.-e, loir, tract lire of fibula. 1O77 in pregnancy, lo:;:;, 10'i7, 1 l.'il K-Oii. !01 1. S,-,- also I'ul- m,,h in renal tuberculosis, Hliit in iheumatic -out, 1 1 Hi. 1117 atisn .an ii-ular, 1 1 Hi nl joint-, 111.'. miatoid arthriti-, 1 1 1~>. 1117 in rickets, 1 1 l-"i in sco!io-is. 1017 in skull fractures, '.MIL'. <<)! in -pina vi-n'o-a -vphilitica, 1 1 !_' m -t rictnre < <: e.-i iphairus. '.''' t in sr.pi)iiration ol antrum, ij. - pi.:'.:- i if 1 --, 1 1 H 1 - : il.-. 111-1 in tab,-';,- joint, ills in talipe- , mini;-, losi_> in tutierculo-i- ol bone-, 1120 nl can. i..-. 1 120 --: , llinw, ! 12s '.112" nf kidm , KHil 01 knee, 1 120 ol ii ,-tai arpu-, 1 120 in lun.or- ol bom -. 1 lo:, nt-', 1 H'-, . 7 ; i . x.,.: it, IP, ' ajipar: tu- duriiiL'. si:; ::--.-,, ' ': for, si 1 - - |no:-;. ii"-:. of innon.inate arter\ . H ni . KIM) of ank\ !o-i- of lower jaw, ','i',7 of anterior -uperior -pine of ilium in mu-cular t'ractuie, 1071 of antium, '.isl. See al.-o nl ai ,rta, loo:, i : aortii aneiirysni, lool, of apex of h;iiL-> in tubercu- lo>is. Kill ol appendix. H'2, ol articulation- of lower jaw, of atlas dislocation, '.''.'I of bilian calculi, 101s. Sec a!-o li;i;,ir ; i r'tlculi. ot bladder, lo:,t ofl.lood-vessel.sof chest, 1OO:5, 1 1 H >'} of boner- alter ca.-tration, 1 HI7 ol In -.:::, ail in ventricles of, '.'i <~i of bronciii, 1O02 call areou-, 100'. I of bronchopneumonin, lol." of cnlcareous bronchial glands, KIOH pro-tatie. Kiii.") renal. !O)s. See also L'ri- ;,-/;/ i,,\, nl,'. ureteral. lo:,l. lO.Vi - - . los. Seealso I'ri- . H"H nl callus aiti i fracture, 1101 of cancer of bone, 1 1 Oo oi neck, ''"'< of cafl.ohx drate.- in >tomach, 102'.' area, lool ai i:.-'--. loo2 '-: carpu.-, in"--; ol ceciim. !02s i ,: cer\ teal ftadure, '.('.'I rib-, i's'.i of ,-he-t, d'.i'.i. Se, al.- ,<>-, K '-'' hi : : ,- cm -tipatio] . K'L's ,' , !:-\ :--],- H 02. loo:; .-, al ill-location, 10C.7 fad ;re. loo 7 - ( - los'i. n",'' i, .chni . io' o T, - po-ili.,1 lo: II ,1 colon, 1027 b\" lo_'7 adioL'raphv of dislocation of Radiography of fracture r I !;adioL f raph\- of metatai -a! frac- eiii-ej \, ]dii7 toil! pro'-oss, '''.'I tun . ins:, of dhow, 1 Id:.' of patdla. 107.", of mouth, endodi i-cope for, of hand, 1 10M of phalanges of ham . 1 1 ()_' 771 of hip, KHis of phalanx of toe, K s:, of na-al -eptnm !'s7 of low IT jaw, !!''.<'. of radiu-, lO'.l'.l of neck. !iss. See al-o .V.r/f-, of patella. 107.-) of scaphoid hone, ununitl 'i. rmli'o if n ill, a . oi radius, 1 lo_> 1 1 1 10 nl femur, K.I.S of shoulder, 1 lo_> of scapula, 10'is oi obstruction oi colon. ]n_'7 congenital, lO'.i.". of siir-ical neck of humerus, oi odi intoid fracl lire, '.'' 1 of divert icula of esophagus, lO'.ls oi paralysis of diaphra-rm, (MM of tar.-al hone-, lds(, Ids.', 1 00 1 of dorsal vertebra*, Iddl of tihia, 107."), 1D7H, 1077 of patella, 1071. See al-r, of dry pleiiri-v, lOl.'i of ulna. Kl'.l'.l /'.;'. II, I. of duodenum,' loi'ii. loi 1 of wrist, lO'.i:), 1 10O of pearls In o.\ -ters, 1 |:-;o of car. '.Mo imite,l. appearances, 1 KM ol pelvis, !o!7 Lance's method, !U(i of fracture-dislocation of e - cxpo-urc for, slj Stewart's method, '.'Hi bow, 1 m:; ot phul:iii<;i - ol loot, KisO, of dhow, loss of frontal sinu-. 11(1.'!. S 'e also Ills.-, dislocation, 1 IdL' frmit'il xintt*, ral"j of land. 10!i:i expo-nre for, s 1 _' of pii i-holiths, 10.-) 7 of empycma of IUIIK. 101:! of -rail-stones, lOl.s, See al-o of pii in larynx, !i'.i I of epiphysea! injurv at shoul- Hilary ,-nli-uli. of )>itiiitarv tumor-, !'17 der, lO'.i:, of L'cnu valL'iim, 107o ol pleural adhesions, ]n]:>, of c-ophaL'cal dilatation, spin- of [in-al thoracic vessels, topo- i ffusion, 1010. loi:-; dlc-shaped, !) tliiekcniiiK< Kilo. Kii:; divcrticula. '.I'll vessels, Kid.'!, 10O., of pl.-un.-y, dry, KH "> steno-is, !)!i.-) of lifccn-stick fracture of of pneumatic sinu-. [leeessory, of esopliacu- with tuhe he- radius. Id'.i'.l !isl hind. 1001 of minima of hone. 1 I Id t >po exposure for. s 1 L> of p.Mipneumothorax, 1 ( 1 1 o lower, Kills of heart in mot ion, sill' of r;e ills, Kls'.l upper, lost; normal, appcaranec, 1dd.~> of ranm- of lower 'aw Cil". of eye after iniurv from for- ohlio.iie. topography, loo:; of renal calculi. 104s. S, eign ho, lv, '.I].". ' traii.-po-ition, 1007 1 --,-'.. of eyeball perforation, !U."i ol hepatic ab . 1021 oi ret ri iphar; ii(.'i al abscess, of fats in stomach. 1()L".I of hip-joint. Kills. Sec also ! I'l.'i of feet, hromid paper for, sou IHll-johlt. of rihs, 10IIL' exposure fo: . xlL> of hour-Ma. -tomach. !(() cervical, (is! I of fern if, neck of, Idt'.s of humerus. Kiss of rotary dislocation of atlas, of fetus in liter.,, 10ii7 of iie.im. KlL'H '.I'M of til, ula. 107.'). See also of infant stomach, !0_".' of sarcoma of hone, 1 1 o" /' i if inferior maxilla:". . !lli"> ot -eai ihoid fracture, i;n- , njrers, IdlM of int.-t inal adhesions, lo_>>; 1. 110(1 of first molar, '.:> rcci;mhc:it po.-iti' i in, nl - i inal ve-icles. KM,-, of fish, 1 IL'J. ll-'s lOL'H nl septum nasi, !-s7 of flat-foot. IOSD of inte-tines, IOL'1. See also of shoulder, 10XC, of tluii in sphenoid cell-, (1x7 /,e'., ,','.,.. di-!ocation, 1 ld_' ot food passing through stom- of mi rathoradi tumors, Id] ) eo I1L nnital. 10!'.-) ach. IdL'S of jejunum, lo_''l exp .sure for. si _' c.f ;, ,i it, KIS'I of kidne\ , KM'i of splienoid i-e!!-. osii % Illli iroscopi ex i tioi results, ;; " ' ' of . t ,ii :' cai ;'. 1017 damn r. i- i'.. 107'J of km ,107^ ill -:- - dli -sh iji : - - ,ph iceal of fureai m, Ids'l ; nt. rop ,..- rior, 107o dilai ninn. ''"! of foreign h' nii -s in .-. ipha- e\p -lire for. s 1 2 1.1 .pin.-, looi. loo:;. KUd. i-'Us. !'!l 1 . ',i''_' of knei -cap. 1071. See also Si . also >;- in eye, '.nix />:>>' '!.;. o! ste losis of CsophafTllS !)!)!, in intestines. lo_'s oi kno 'k-knei.. K 17". '.''.", in '. i ; 1 1 _' . 1 o 1 ." . -ioi -. ' 1.1 o: -t. rne.m. KHiJ in : i 'k. !l'.i] ' ' i7."i - ' h. lO'Jl, 10!!. See in p Ivic iriraiis, lOCni - iii s t o n i a c h , K ' J s ,..., -_ ] 00 V o f s u i ... - i n u - , of fra 'Hire, Colics', los'i, r , [, ..',, ' I., ! Os ] See aUii .1 /' .".-'.-. i- lO'.'ll ja-A , ) .-it ion of 'iiln ; ;:. ' ! ^.-> ' , >'. technie, iOiin mi ,l:i r-. '.'Ml of su] mum. rar t" ,ne-, K i"'i ur, en-tick, Id'.".' o1 lui har v rt. line, K'i',7 oi -\ mi,hy-i- pt;l i-. loii'l 1 ilnm. 1070 :-.'''. loo_- Se, - ' ! fracture, Ids 1. Ills.-, i,:' anteri.ir sup rin pim / ol lar-us. K's:; . 1071 : : ' ' l!ld-, pUl- of teeth. '-- , .. . . ., HI'.... . H ills ... , ' ertel .".e. '.I'.ll ..-.'.' 1 ' . , l] .'.->..' - ol davi.-le. IMS f ! . , '"s. IM r, . : ri : .-:.. lo;j INDKX ' : ".;losis, pulmonar\ . litnl. S, c also of tun irs. intrathoracic, 1(110 - . : _ . I o 1 1 . of in k, !".'.". ol piti:itar\ b..d\ . "17 of s] , '.'xti cil ' '.' bin ited i.. Hi. -, "-> 1 uf 1 ph id s] in. . ln!7 ol u'liia. HIVI -. til. "'.7. "ex oi up].er bicuspids, v:;.' -. "'..1 r-, '.'.;_>. 'i:;:; i ter. ln.-|| ol u ret i ra! a! Ii. 10.VI, In.,.-) ul urinal . lii. lolx. See - : -', lllx'.l til re. KI'.I'.I . . phi . ' '7. St'.ix .-.. M. ,-ure in. xii' . lili.l injections into joints ; .:.-, 1071 . . . vl|l , peic trai n oi lay and, -.;.,, Kadioi:raph\ . \'acuum in tube utricles of brain in. '.Mil \\ith hii.'ii tubes. x:;r,. s)C, u ith low tubes, sijii. xlu with siimlc Hash, -~,,_> impulse, 711 _ Radiology, determination of anatomic a<_'e b\ . 1 ll".i Radiometer.- for' r-ra\ work. 1 l.il', 1 I.".:* Hampson, 11. Vx Sabouraud and Xoire's, 11.1s, llx] Schwartz's, 11. Hi Ti .iisi ;. 's, in frontal sinus fluoroscopv . '.i7x Walter's. M:'l Hadiometric tints, Bc.rdierV 1 lol. Hadiophotometric m.-tho.l ol Hadioiiuaiit itomi tcr, 1 1" 1 Radiosclerometer, 1 Hit : : . . -.':,.' pcnetrat :< n < .; endodiascope for._771 \-entl'i! tube- ill, , XII i-adio-activitv . ll'l'i ba-ed on can:n:a rays. 1 1' 1 1 i '-* s iler-ompo-ition oi tatty acids i . ! IT,.) . ! Ic'.cithin 1" . IJ.Vi di-co' er\ of. li'pl lli-illteet'io! . '. i.'i.: ' . I I'd--. II-. 1 1'ti.-) Radium in earth, ">_', ll'lii in pitchblende, 11' lit in solution. 1 !'.".( I, 1 _'">_' apparatus for. 1 1'.'iU induced radio-activity from, influence of thickness of layer internally, dosaire, l_'ii.> iuiii/ation b\ , ll'l 1 measurement l,\ Sabouraud and Noire pastille- of ba- rium platinocvanid. l_')x metallic, produced b\ distil- lation, li'ln ointment, li'iiii oriLMn of, li'ls produce. 1 from cariiutite, ll'll* production of helium b\ . 1 .'.", I properties of, !_' in puncture for carcinoma, 1 l'7'i ].ur... effective emanation radial i. .n :n ,m, ! _' 1 1 pigmentation by. l_'lil railio-activiti, of. li'S'.i ra\ s, ab.-orption of, ll'."i:i b\ skin, li'iii' alpha, ll'll'. \'2\'.\ ajiparatu- for. ll'i'.ii api)licati..n, li':>x bactericidal effects, li'.'S ben. : .al . ::'. cts, l.'.Vl, ll'lil) beta. !.'ll. ll'll' ehemic eiTects, l_>.-)5 decomposition of -odium iodid l>> . ll'.V, derinatitis from. 1 1'.'.x divided applica'ion-, 1 _'.",x dosaire, I I'll.-,. S,,- also lh ' on animal's'.' 'll'iTll'" on (leveloiimeiit, 1 I'l'i.' . ll'C.l on growth, ll'iil' on heart, lL'7-~ eN]iosure . .1 ni il'lnal -a hue . ll'f,7, U77 camn.a. ll'll. ll'll' irl is.- ' . 1 1'ii 1 . ll'.V) in acne. I i'7H : ii i ia. ! _', I' IP ait hriti-, i l 1 Jl IXDKX in nervous diseases, 12, s in neuralgia, 12t>-~> facial, !27s in nevi, 127(1 in papiiloma, 1271 in pruriK", l-ii'.i in ]>nirit us vulva', 127 in psoriasis, 127n in radiodermatitis, 12i>',) in rodent ulcer, 1_'71 in sarcoma, 1271 in 7-cnilc \varts, 127 1 in skin cancer. 1271 diseases, iL'd'.i in -mall cpit liclioma, 127 1 in sycosis, 12711 in trachoma, ll'til, !_'77 in triircmiual ncuraljiia, .")Ur., 1 l!t:5 in tumor of orbit. l_'7."i in urcthral diseases, Ulio in uterine diseases. !L'ti5 iihruids, lL'77, 1L ) 7^ in vernal catarrh, 1 277 in verruca. 11s, l-'li'J in warts, 1 Is, iL'li'.l ays, caluritie, isolation by i|iiartx Senses, till.") magnet i--, (-,,-,() mau'ic-tocathodii', li.'iO ld(i 12H1 radiography by, 12">ti resistance of seieniun and. 12,-).") rhinitis from. 12.".s for hiL'h-fre(|Uency current, secondary, 1 2o 1 Flfminjr, .",:;'. I separation by inatriietie for t ripha-e current.-, 10.") stnmir application, 1 2.",s theory of, 12.')7 treatment !,y, |2f,:!, 12(i!l (.; -olut ion of, !2or, standard. iiit.>rnationul, 12tti -uliMinitc- for. 127s use of flunrr.srorH! daiisrer- ou- in, in' t Iti-iiiiai' seb'-rcetifyim; jr-r;iy Hc-iiioiis cli-ct rieity, 1!) student.".-, 2MI, 2:',2 tiliinu' bol>i,in to. _'20 for GaiiTe's transformer, 74-1, 7 (.", in i.'ah-anoineter and shunt, Iso in voltaic cell, ,s.",, si; ind ictivi . :<}. "iH ::-.;:: ,c in of circuit . mea.-ur- 1322 . . Io-t by, -..Mo : - : -' .' inir. 17^ ::.- .-. :. _'Ji ; - : _ : u :i. _'_'* unit , 171. 17.'. _'l'.i -.- :. -. If, K. tii. L .-tT.-t of i l_'f._' [,'!: :or, H7 H. .....-:_.. b-ei --. r i li- T '-.' '< ' iinir, fiOO iirim . f,0 ;. rr .: , -.a;,, .r ii^'it l". ir. tiVl r-alnpheii for, oiil tripha.-e eell-bath- fur, 1 IN ti;l" : il;ir, /--ray f, '.'. 1 1VI x-ray for. lilKI, tiOl, 1 iv.t, 1 1'Hi EUii'Uin H oil 1 :irl '.:.' -, ,rin inntophuroi- ii,. 1 1 i iliatin-nn : ii . 7'i fariulir' current [i ,r, iL''i H()s faradic current in o'-ular par- . 171 f, ;^ii Hibbon inter] iptrr, 11- . ,.-tat, -"I". 202 Hib.Mit and Marie's table lor . sltj Kill-, cervical, radiography of, traphy in, 1 ! I. 1 hi irt, ion-, 'I'. ';--.V inetliod of dorago, 1 I'.l voltajif for, 7.V> liiniueii-ray, (',.",( i. r,:i_' ab.-orptio'n "f. li'.i.") \>\ air, f,'.i.^ n i n : r.f, 71 I after nerve re-ectiun for tic alterr-ttiiiL' ci;rreiit trans- toimer for. Ififi- Uis nnirnint of, tor treatment, 1 17,2 renif-tfi for, ^."iO ami ili.-rh:.i-L'e rays, 71.-, am n '/: from, in 1> ukcniia, anode of, u-e of alone, 7f>0 fif, ()!!), 7(10, 7.7J n, 7'io n],parat'.-. injury To. in radi- radioL'r:tp}i\- in. '.'!'. ;iproii- proo! atrain-t, M)2 ; tube for, bactericidal valm . 1 l^'l ol.V baliin,-- from, 1 \:>,:>, 1 lo- m, 7H1 pi.!- pha-e cm rent- ir . 7 ! l-'7 ., , 7 :l t. ::.-' ' . ,-ed ma.-net, - - . 7 : : a- unipolar. , , ', :. MO II-..; l.r.-akiiiu :. .:> Mrickm i 4 - -land tor, M7 . , ted !, 71 I'.l ill- oi, TIHI -tn : . ;: . 7" ; chan of, 70-' IXDKX RontRf-n-ray, bipolar, electric IlontKf-n-ray, |hi[io!ar, punctur- 1; int irr-n-ray, hipol tr, v. it!, in- generator.- for exciting, iiiL' "i, 7"i-.i i . r-urient. 70(1 71.", I'upin'.-, 77:1 with o-mo-rcirulator, 701 1 i-ndodiascopic, 771 (jueen self-rejjiilal IIIL', 7i'>:i, without ant icnthode, 77_' excitinL' nf, d'.l'.l, 71"> 7(11 i\ ithoul internal elect rudi-s, hv indl|ctioll-coll oper- n-lu-:iiL' to tniii.-mit cur- 77:; ated by cliM-trir- rent. 7"i7 w it re; lor, liirht ' current, re-rn!.i:ion of, for nnliotr- .vi-riiit', -Hi 71!' raph.v, 7n i rai.-iiiL' vacuum ui xnr. l).v naivanif cells rc-i-t.'ini'c in, tor radioL'- hi-i;h,l,:itc oi nuinin with, 717 rap!iy._x ; U !_':;.", hy r.oyden jars, 717 lirotii! - . 1 i:;i h\- static' machine, (ill'.). "'I'iiTaril'.^O.-) hum.-, 1 1 ]_'. See :! 1-.. /,'', i- 71.'). Sec a so &/,; secondary current from, '/ n-fii'i -'' rni'iti't. . Hindi in' for .r-nnj ii'orl;. volume of, s ."i'.l Caldwell interrupter for, 7 JO, hy jr-ray coil, li'.i'.i' rays from. 7dl. Sec id.-o 7_'_' exhau.-tion nf, Vlx 'Sn-ntnlnri/ ni'/x. interruption- oi. v.'.j extra rays from, 7','1. Sec si-lf-n-milatiiiK, 7i)l wit!, alumimin c, ... s.-,l also Si-raii'liiry riiy*. ( v )uecn, 7i','.',. 7H! cancer from, ,0, , 11 )i; r>0-i-f>nt inn-tor, 7.">s, 7o'. Thompson's, 7iit cathode ray and, liol) fluorescence of, 710 Dimple form, li'.Hl changes in torm of stomach for mouth. 771 sinjjlc-focus, Tou.-c\'-, 7H7 : i hy, IHL'1 for radioirranhv, 7"iX 7iil_' small, 7.-.s in niotiiit\- o: rcfiulatl !', 70d ' soft, 7o:; found hy, IOLM Tousey's, 7f,7. 771 .-l)ark-i_':ip- for, ,01, , M'. icterist ic honii iL'i-iie, , :-, for treatment, 1 1.~>1 sparkiiiL', leimth of, 7: 11 i i 1 ii i Friedlander's water-cooled, seconilan-, voltaRc of, produced hy heavier 7(>:-l, 7o [ 7:;i metal-, (".'.til ' pas in, v'.'.i stand for, M7 C'liarijonneaii's trati-f' >i mer helium, 7f,."i ^t:^r ic ncu'lii ic for -xcit iiiir. for, 71'i "in-- i if, 77l_' 71.',. See al.-o St.,/;,- mn- chi mic elf, 'ts nf. 1 l.l'l Gu'iilciz's. 77:-! rfii/ii for x-ray TO/-/,-. mil, l.'l. 7:>n, 7:11 Gnndclach, heavv anode, Stern's unipolar, 77:! choke, 137, l:;s 7(M) Morair.-ha'tery and in l".c- effei'ts of >. orkin" n >ar :)' i7 liirht anode, 7di> tion-coil for '-xcitinst, 7 IN for hiL'h-frequencv n n;, water-cooled, 7f,:i tariret ot, li'.i'i. 70!) :, i.; liard. 70M, s:-i 1 tcchnic of u-iiiL'. I'.'i'i Pill .-i safety-tnhc -. hit, heavy anode, 7o(), 7i',l Tcslu's unipolar, 77:', 7i)o liiirh. 7n:i, 7(H 'rhompson'- .~e!f-reL;nlat- self-induction in primary results from, Md imr,'7i; 1 of, Kill, l:-!7 hijjh-fn-eiueney, 7dd Ton-";. '-. l-'lx xcit.il hy, opt-ra- lllti-l tiat iiiL' M'Cotidary hifocal, for radiography, . ! i 11 ciirri-nt, 7.'-i."i 771) winding or, ].-,! hydrogen in, 7dO dosaiie with, iL'l'.i conductin,; cord-. 7:io .. ; , ~' ] t' 1 ! I ipcl't 1 'i '! 1, il 1 - ill. t Ol t induction-coil and storage- 1 ' >r j i v iiT it L ;L Mlvffjlun.-, Dili t eel- lor, ( - ,o battery for e\i-i-inir, : ir " nlii ijtraphy, 7i7 1 t T . 7 ! ', 7lN trained. ^ to : - . ' tin n . . i' 1 ' ! operated hy plcctric- tunir.-t 'ii target, 7ii_' cumiil :-r e cffi et. ! l:,l. ] 1 |.: liirht rurrent for cx- type of, 7JS curatn-e value ot", 1 loll citinc, 71!) unipolar, 77:1. 1 I'd cure in cancer < if lip, li'l'i injury to, in radiosiraph, MM vacuum of, loweritiL: 7'i'i. ;n tit. voltut'e , :. tin - '- inver-" ciirren! in, 7' ; ''i. 7d7 7i)l . ^ 17, S:IN M'l , 1, 7:> dischanre of, 77H iiM"i-uriiiLr. N:>:;. ^:i 1. so.'i, dare'i ' '.:. u-e o , 7' '' ' suppri'sMoti, Mil M:: to liand^ from, 70ti hi IX-. 7AS rmli iifruph\- an 1. s:i) il:i;._'e!on- in production of leaker, li ''i rai-inir. 7lU, 7i',_', :',<\ -teri'it.' . 1 1 17, ! _':> : lion, 7ii'< l.i" id '] iar- to exciie 717 wi 1 1 u 11 1 1 n -sii i . ~> ; , ' ' ' i : . . 71*) . tl, from. HID line IM di inarcat ; m in, 7'in. - : -. 1 l-'ii. ^: i^ rai-.-, s:iii di :.-,;;. and. I'.'.i.'i, li'.ij locaiizini;, 77_' valves of, 71 17 ., i ].;_' !.,-, 7n;; \ iiricl ; . -. ti'.>'.l 11 ' 111! -cri'i I! t ' P'. - . 1 1 '. -,-, - , 7l ls > n. Mti -.71! - '. i i ; ; Maclil, i; hiL'h-tre.iiieUcy, vi-ntril tnli. - i::. 7v : 1. n-i tin ir\ ,.:', UM7, , liil -eric- \\ itli 7x'l 1 " s water-cooled, 7t,:; Nlllard's ..MHO , decrees of. 11 i:; iiieditiin. 7IM for, 7ol, vsii tro! . radii 'sirapli' . x i - Morton, in ,-: iti fliojna, with , -- : _ - - ;.'."_ 1 1 .". 1 ~ ' i ' > : - . [jni Miiller's 11 11 Volt-' '!.::. 7f'.l -en-. ii - prevent, water-eo,,led. 7>;:; Wat C--CI ,, ile, , , l'i ! ," i i] , .rat ii ii .-. li ' i u at i !:.':. ' .. li c; i,~,-i!!o.-.c..pe in si !.- . i . ' . 77J o : hand-. 11!:: -' r,-i;!-tior lor, 7f,l - , ( i - :>. 1 1 (: ;-.:' . , 7 ' ' * , 1 I ! 7 it, 1 1 !J -. itr,.. i i !_' . nil i I. !i:ii) "i rnea, I |:!'.i on ei - i!lii , ' n-. 1 1M' oi erytli'ro -, 1 1 !_' on e.\'i . 1 i:-Js 'i M.;, i i:;t;, n:-;7 . i i.i.i 1 i: 1 :-; : - -;, -tern. 1 I H) ,,[,tic :.. : e. 1 l:;o ! 1 .''.'- in indurated cleat rice:-, <',1_'7 1 iou.- di.-ea>c-. l_':-;s in int. reostal neuialL'ia, .".(i7 in iti liinK, I I7s n ii Hit tubcrculu.-is, US'.) it. fiL'7, 117i, in kidney tuhi reulo.Ms, 1 Is'. in lar\ nueal cancel, r.d'.l tuliereuloMs, <',ds. r.d't in lat. ral selerosi.-, oil :-.-.: an.] relati L'a-t,'ic tindins.!.- with, 10L':: i:iireeti!;ed t ran.-fonner as, 7 i:; hand for totinir rjualitv , Ml in, 71.; In ' roi_'eneoii>, alj-orpt ion 1,\ utei ia],-, i'i'.'7 iciic; coil ior, "J'e-la. 7fJ |,i-t, ],, L ric effects of, 11 U :-. tuliei .iilar. 1 Isii rea I a . 1 1 7r, ... ..i KIS ii irthriti- "d, '.:::. MI-. ! I'.id . 1 17s 1 Is.',, 1 is,;. ] ]x7 in lyuiplu^arcoina, 1 I'.is, ll'IW in maiiunaiit di-r a.-e. 1 lijo . ! l'.i:J ' in moles, 1 17s in ii:\e,,M.- luniroides, lls:{, I.'::.; in neu-al-ia. .Vi3 facial. 1 I'rj iriti.-, '>'.<'.', . Us, i 17s in old -i, ram-. 1 I'O in nfi-liiti-. ."is:; . iti.-. tul.i n iilar, ll'.Ki in o-t.-nmaiaeia. lj:;s in periadeniti.-. t i:l/ereu'ar, in ],en!i,:;eal tuliercu!o.-is, 1 iss ; iss i:. pi rnieioa- anemia, 1 l''s . , 1 I'.t'.l in p "-v. .!. -:: ; m-. I 17s in pn in; c,,-i-, !_':;;{ in pro-1 a ' ie I . ; .1 : t n ,] ih\ . i r.-i. 1 1!'.-. i pi -1 . -. ! !'<:. 1 p..:, 1 1 1 p 1 1 ; r i t u .- . i 1 7 v . I . .-, 1 1 1 . in ih, uinati m. ill Ml. Hill, 1 I'.' her' ir. 1 I'.'ll ei,,! ,117(1 11 i; : '.. ' a-, . oil. INDF.X in minor i. in ul. -cr.-. 1 [7!l rodent, I-'KI ii: \ crrujra. I 1 X 117s in warts, I Is. 1 !7s in \: 1 1 1 1 1 1 1 1 1 1 1 ;i : 1 1 1 1 ! ! i 1 1 1 1 \ . 1 1 L". i induct ion-coil and - r "l: battery for cxcitinu operate.] by electric lii'lit cnvrciit for, 7 !'. In- jtMlvaiiic' i-i-ll>, 717 sci-oii(lar\- curn-iit of, , .'i, iiillurin-r of, ilurinir dr-vi'lop Hontnen-ray, lenkotovin from, j liontifti-ni . re-i-tano- t' IJIi:; ' rheo-ta! lor. s.', ] I.eyden iars for, 717 I.,-'- nt r-'iiht from. 1 l:i'i on, '.Mill injection of photodynamic substances before exposure, | !L'::s injiin , \rnei ican radiologist.- I mtrn.-ity nt. s |s MIT-L'''!^!^'- Mctinoinctcr to linr i if (in-atcst, s Is rent and. stll_ intcrniplcf, \:',7, i _'(), s.'c> Hcakcr, 7L'D. 7i':; C.-dd\vi'!l, 7L'0. 7l'L'. s.'ii'. s."> l uilh aliiininu!!! i-i-ll, s.M C'a'-pi-nticr'.-, 7_'s character, s.'i_' ci in inutati ir i ypc, 7:17 C'ontn 'Moulin; 7Js Drault's, s:..-, LC, iniTcury, I'ari' r. r'!s - .-..::. -' '_ liiciu . 7! ! metal, 71 I diaphrau'tn, 7'M mild applications, phy-in- imrir . tTi-i-t.-, 1 i:;n 1 1 I'.i ill-.' urri'iit, 7-n'i 7 -Hi direct current, ")() nephritis from, 1111 1 i:;s : -cul'ir t ronhic ac' ii m li ir >a.-r. '\I-YK bra! art liri- ti>. in; i I'm- n<- dnti'ouri'iix, ln;i line -nlutinn- inn! -kin, cur- rents : : ,, L'ti'.i lectt i'- rnniluetivity of, :;'.'7 :. rcrvica! s\ mi. at! etie, M I' 1 Inphen in rheuinatisin, r.nl - - . f.,r. 1 1 ~f, : . : b<.ne, radionraphy of, 1 lor, ..i ;;.,>,. --: .:.. !_::;.! . 'p. ;at inn 1. .r, i -'Ml ' !_':;_' in. 1L'71 '.11 lili, 1 I'M] : ' ' ' ' ' . ' ' . ! -''' alp. : :-. 'i.- nf, j-ra\ in. 1171 ' .] tnnia -, ;'ra I ire oi -, !id, f! ill nji\ tn n ntiate, '.(il < .sr-ntiv tn dilVeri lit iate, Sciatic in urit i- i,->ti'il by Matii' \v:n c , urrcnt, ..il'.i hijxihir liritli fur, "ills li!i:i -iiLriit hath- in, tN7 i-utniihi.n > : .> I'nr. .Ml'.', ."10 clirnnic, .Ml^ I'.dM-ilkit'-. trciitlnciit, .Ml'. I I'lrrtl - for, 507, .".II 1 . 1 nr.iu-ni! liica.-uri's, "illl - . '. i i : : .: : . ."()!) 'tit H. !;..i,- cul rent fur, .Mis iliatli. nny !<.r, i',:;7 i'!cctric-it\ for, .Mil, :>(it> , M i7 laradii' current fur, .Mis r i .:.:.' ' -..Mil )iitr)i-!rci|iicliry curn-nt f..r, atlis in, I !:; !!l.ii]c..il ci;lT(-nt !'. if, .Ml'. I I! :,--:.-. I'nr, ."ill! ni r\ i --t n t.'hiiic lor, .">IO inn fnr, .".in .'|..u'ii.,-i-. .IK) , cii '. Icrina circr,ii!.-cri].t a. L'al- iirri-ntr- for, t_''i tra!\ anic current i'nr. -IJii static i iri-1 1 i<- : ! y : .1 . ! _'7 j--r:i\ in, ! Is] y.-V-'in, 17.-)" I'li'nrin ca':i]ilinroir. fnr, 1O."> latcl , i-li ..... .".11 iniiltil.lc, clci-lri-'-ity :..:. ."! ! i.-, r:'dinfrra]ili\ in. 1017 li-h-n ark.- nn |il;itt^. s;ij creens, I'l.rium platinncyanid, .-: : work. ll.V,' . iar. l'.U'-k\ . fnr am -1 ::._' -i i . .111 |ar\ ra\> fmn ti. >UI -. . l.'.icc of, sjx ' ' s_M 7'.' I .;. f-,i i , r-ray expo-un^, Tnn-rv '>, HMt -P. . itod in, 7:;_t strength, mca-iinni.', !">:;, ir,7, ios rays, 7!U ari-iiiL r it. tissues, suppl'c -ion of, filter i-l '- plate lor, ,V>0 Cole'- observations on, 7'.i7 derma, 7!M S, retii in ciirrenl -, _'7o Secret. ir\ di-t iirbances . if ;n-li, electricity for, i:iO e effect of ta'.ic protoplasmic, 1<;:,, -Jlili rea .finn of, till, H',7 .-L" .'-'it; 1 ! distribution of, K>7 for, .",! ! iort-circ'iiit, -HI (ire from, I'm; of volatic cell-, no I _,._!; j rlisliii-atuin of, I'adiotrrapiiy of, HIM", 110:3 radio-.-;, pl.y ,,f, (fl'.l.'i epiphy~eal iniui al raj/hy of, MMi.'i rluoios.'. u p\ of, III-M; '. K'l'.Hi ob-cutv dUea-i f, rad r- rapli.s in, 1 Hix Seed .r-ray plate and Ka.-tman (iup'.itizecl .r ray film, tive speed of, M 1 relative -p.-ed of other plat, - and films com- Shove! eleetrode ;, fiy.l pared with, s| I : , , : - S, i-Ii ;. .. :'.;, apparatu.-, -o" Sli nil eii i;it. |s7. L'l i. ; Selenium cell in'ellsitler to ' 'n eleet rother;,pei;ti. , -'' mea-ure ^-ra\ d, .>ai:e, re- i-tanei : . L'a 1 ] 1 00 : id in r:i .- ind, IL'.V) S, f-inductanee in prinnrv coi api ral ,~. s.">s KI'.I - li-iiidiii-tion coil, 1.,: - : troi; . !:;o, | ;u o,i .......... . . ,. . en-. I in .in- iiiiL- c,,rd.-, 7:,o ihiru.- el, .-I,], ii.-, ".t ilver el,!,, rid c, !|, MIJ, !i:j meter, L'4'.l ine fralvanometi-t>,'l!u" of :iwr!c . Mill, I'.il I). !Mi!l. s'ee al.-o ' /'-''./ trail-illumination of, ( -x! anti r'opo-t 'lior, '"'.'.', !i70 sujx-rior, raili .1:1 t| I'M. See !il.- . Ai 'rum, tor chon a. 111 for , OOo for diab.'t'e-. 1 !_' for hi : :.--.. 112 ills. '.I-' for h.\-])ertension, I II ;, r liicoinotor ataxia, 1 1 1 : - :. rvtm- di-ord, rs, ; 1 1 n -thenia, 111 for neuril i-. .")( lor p iral; -is, I l_' I'-ir >einti:-:i, o, is fn ,;:; rot, -IP. converter, !"._' _, n. ral ij:'li 'at i, in.- :. T .1- !, t- Ml. Ul ind iti in- f. .r 1 (_' N 1 .:!!, rliythmii' variation, !ss i therapy, jamph-s of, 1 "_' 11 i. :,'!,. Mo : Uaynaud's ! I .") !-.. ,rie bath-, ft.', prii i| . Ill 1 in -.117 .tin pa ral -i-, ! H ' in-ill :-, 1 III : : : ' :.-i- , f, _.7l I'ele - t>l 111. -'''' 1 N i > \: X . 1 _' . 1 St i 1 - ' . . 1 ! . :._. IJ'.J - . :. I'll I ill nl, ' n ' : ml, Sulr Icatln-r a- -'Tern f-.r -oft . .>_'. :;v, : . ..-; \\ - -. - ;.,-, .- ,,, t -r in, ; ' i .- ' _ ' ' . ' . - 1 a I II. 1 IV, v, :; ',, ..'.id - . HIT, 711 .'.-...- of, ':;:; (-1,-rTroly-i- .,!', li'l \ ),;,--;: -of ,\ ]) in, IliKI if, 17."i i-aiial, hulli ' in, T , ilii iri in, KU7 r'olun.n, lati'Tal '-1:1 val iri . 1017 I' ( ,ir- di-,.:..',. of, radinir- raph; ::.. KlUi radi.ipiaj>h\- uf, 1 ni 1 1 , Ion.;. i o i ; plirat'ii) lor, HHii I U'l ipll il KU7 i -. pl;nid. radii itrraphx - .: . 1017 ford, ili.-i-a-..- of. i-I..i i . x - - : .,-.:;!! in- ..t, UN in :, and, ::l 1 lati-iit pi-i ioi! di, :;.;u . . , -lilt" ''.. '': 1- inncrvati'd liy, tulilc, ',< INDKX po,,_;e electrode-, \.\ .M. ,M ic elect i i.-ii \ . circulator-. Static cleclricitv from -ound 55 and in.-ulat.-d handle, .;x| functions and. 72 from uind', 51 >oni;\ platinum, x:!7 condensation ot -team b\ , from wood splitting 51 ...I ti-\\ood's induct ion-coil, 5d p-neial stimulation ] ro- 151 counterirritant ii-e. 50 duced by, 71 principle of electrolytic in- death from, .".(id glandular secretion- and 71 terrupter-, 7211 definition. 17 irlow discharge of, 57 .rains, lumbar, elect ricit \ for. discharges of, phy.-,ir.-,l ef- heat from discharce of. 5s CM fect-, 55 piodu.-i ion in l.o.K a nd. old, r-rav in, 1 I'M dosage, 70 71 .ra\ director, (Id measuring, 17 heatmvr effects of dl.-ch.- re,'' electrode.-, (id unit, 711 of. 511 indirect, Tousc\ '-, lid d- namic eleel rieity and, ll.\ pilot ic effects, 72 H'lne; catarrh, elect rol\ ->i - in, comparison, 2H, 7.x effect-, :{()5 i n elect ric eel, 5 1 fish, 51 >rintremcter, 7:!1 electromagnetic, 57 in t:\-mnotus, 51 aininc solutions, X72 , -\citomotor, 7:5 in nature-, 54 ains on plates, Xdl on air, 57 in plant life, 51 and, .r-ray, Used by TOII-C\ , on mii.-i-nlature, 71 in Kaia torpedo, 51 XI )( 1 on .-kin, 220 in Siluriis elcctricus, 51 Clark's, d2 physiologic, 71 in torpedo, 5-1 induced, 112. See also >'.' lit, Fleming's, d2 thc-apcutie, 71 utilurttl fiirrrnt. condenser, 2:ili electrodes foj-, :5 for contusions. 7:1 7:;. I2d ,-edative effect of, 71, 7 _ tor ccchx mo-.-. 7:; lot- insomnia, 72 se:isor\ stimulation b-, , 71 for cry-ipcla-, 7o t,.r k<- oid 1 '7 -ourcc- of, 51 for habitual con-t ipa 1 ion. tor lichen, 127 -jiark.-, application, (HI. i.ii. t:i 1 for low arterial ten-i.ni. , 2 value, 72 for infant ile cerebral pal--. , for lupus er\ thcmatode-. -landiim of hair on -nd 517 127 from, 21 for mild muscular pain-. 7:; tor iiiorph.-a, 127 stimulative effect,-. 72 for ncurasfl enia, 522 for ne ira-thcnia. 521. 525 t lierapeut ic indie-it ion- for neura-t icnic insomnia. t . n* oh.'-it \-. 7M 72 52:-! for ..xaluria. 71 tissue chanties under. 71 for oxaluria. 71 i. ir pelvic disorder- i' h treatment by, 5d, Hu for pruritu- vulve, 7:i. 127 Inperemia. 71 accessory apparatn-. 1! for sciatica, 51 )x tor_ pro-tan.- In p.-rtroph.. . electrodes for. lo for -kin diseases of neiirot ic 1 .eydrn jars in. 12 origin. 7:1 -or pruritu-. 127 position of patient. 1 1 12 for suppura inj; wounds 7:> ;. H- p-ona-i-, 1 2i universality of. 51 for torticollis. 51d tor radiodermatitis. ! 27 u ave current. ii:f. >.-. ; Is' ' tor u"ica.-idemia. 7 I for -ciat ica. 77. 50d Stu'i,- inin i-iirn ><>. t. ir wr\ nee ^, 5 1 d tor sderoderma, 127 . lectrodcs, C-; indirect , lili, H7 for -cxual impotence, 72 electroscope. 1211. 1215 -park an. 1. fix for -kin di-.-a-.--, 7:',, 12i. ia-ad breeze, 12 hartr. . unit of d.-n-m ,,t. for -luiriri-h w.nind-, 127 induced current, ii:i, (15 71) for -pa-m of external application of. li], \\> -, , |. HI. 'Ill's III . .bc-l| \ , ~.', -phincter of urctl ra. l:;n effect-. :i05 ' '" '"'' '"> - ls - -'"' d .uloureux. 50ti I-!.-. -trie c. nti.-ct ion '"- tor varicos. veins, 127 torfunincles, 7n and u a t.-r conipa n-,| 5i 1 5 1 "i -tiona! -our,-,-, 55 tor motor distu'-bat animal _TOH ; h and. 71 'rom ch.-mic process,--. 51 o; -toiua.-l,. i:;| vital pr e.s and. 51 Irntti -ont ad , it . li--m for n-i, sei lar paral; -, . ipplications of, .Ml metal-. 55 :, 1 :; iii.-t h. .. 1-. o 1 un .-ry-i al'.ix.at ion. 55 lor neuralgia. 71 -Ml.ipsl-, 111 in.ni elcctroinatrnc! ie in- for neurasthenia, 52 t IN'DKX ^ par.itii.-. 'l! ill con.-tnict l and I ". 'I'M jar- arrant: 1 in. ir L'l I-- Vacuum el trode- cuiiiicct p- I fr-.m, Is .in mL-ement .if, Ml H ik< r, for s-ruy produc- tion, 71.1 paper disk, :7,:.x t..r UnntKcn-ra\ work, .i7. .{.s - il.-initi chlnrid as desic- cator fur. .i'.i i in- Hi. I'.i carriei ' if, -'_' i haiL'inL' I ,i'\ d'-n jar from. _'tl - l.ru>h i.f, :i-' conio iif, .'har^' in. :il rond.-ii-.T di-chari:,- from. at hiL-h potential. .'id 1 ' "lull ii-' r- in connection with, application. 4'.i"i application. 'ill : \r~onval hich-fre,|tienc;. desiccator for, :v.i di-chart."- between pole- of, J 7 . _' s drying. l>\ compressed air. (0 , .. -.p... -'1 efficiency of. 1.1 ti.-l.l plat.-- of, .;i [or radiocraph.% . 7Hi ior s-r -. work. 71.".. 1 I'll miiliampermc, 71'. panllr-l -park with, 71'. 1 1 i in. 71'. li. tn .-,11. .M7 : Vr-onval. H.', Ho _', :i:i netic extraction of. -l.lt un-laked lime a- de.-iec:iloi Stein'- phi-tic radiographs , ss.",, for. 10 xxi i voltupc of, 717 j Steno-i- of e-ophacu.- from m, - diiistmal tumor, radioj:- raphv of, (l! 1.1 radiography of, '.'.'! .r-ray tube connected with. >icp-doun transformer.-, llij, 70:5 in:-!, in:,. 71:; excited in . opera! ion. a.- rectifier, 111.1 li'.i'.i uroundint: one hole of. :-H,.1 modiditie- for pre. lire in- Ste]i-up trail-formers, 1',-'. lti.1, filtration with jiain, 71 7t:', re-onator eflluve for hr-rpe- : current from, I'ld zoster, 7:-; .r-ray work. ll',i'i_ -park, application, l!i.1 Sten-odiojtr:ii)hy, s]7, x]s eounterirritation from. 71 value of, s]x effect on ali.-orptiori of exu- without -tereoscopc, MS d.ates. ~'2 Stereoscope for exiiminiiiL' raili- lor acute muscular pain-. ojrraph-.sl7.xls. 7:^ mirror. PIL-. on's, x]7 for chronic constipation, 7:< -tereodio^r:iph\ without, sis for exophthalmic t'oit,-:-. Stereoscopic fluoro-copy, MS .IL'H plate-holder. ''7.1 radionr.'iph\-. sir, in dentil! work, !M,| of ant rum. !'s, of conirenilid i|i.-li " at ion of hip. 1071 of ,-thmoid c.ll-. !ix7 of forcimi liodie.- in ra- n m n.. 'ii i', in neck. '.''.'1 . l!'s of frontal sinus. '.', .", revuL-'ive .and d.ti\:i'i\' of lower jaw , !Hi.1, '.Hill effect.- from, 7! of pneumatic -mu-c.. '1x7 -tiniulu.- to resi.-tanci ,,i ur'm:ir\ calculi, lo.lii ayaitist di-> :,-, . 72 St, rilitv froi'i atrophy, el, - Ionic ,-ff, ct- of. 7-' vasodilatation :i ,, coi .1 n , ffect of, 71 ,lt meter to m, ii.-un diff, r- . lie, in l,ot.-nti.-,l at pole- of f.lbe, Sol rho-i- of livr, 7:. - - induration in tt m .71 .11 i 1-.. b- i;al\i,ni. ciirr. nt. 1st t, d induction -ii' 11 1-. , |s| i.- l.ecln 'iirrent, t r '.: I. vari.-ible current-, law of. INDIOX Stimulation, cerebellar localiza- Stomach, cinenialogt ,phy of, tion bv, 310 author opposed I i, 1033 cortical, 33!). 353 diseases, galvanic c urrent to eye muscles in, 3IO pneumogast ric tiers e in. perspiration from, 3 10 131 current for, 331) high-frequency ci nent for, degree of excitability, 335 (109 l)ii Hois-Hevmond's law, 312, electrization of, 130 313, 3X7 ' effects on secret ii n, 350 effect of carbonic acid on, fats in, radiographs of, 102s 312 fluorescent media ii , 1235 Hoorweg's formula for, 3SS fluoroscopy of. 102:' in neuromuscular prepara- author opposed t< , 1031 tions, reactions to, 331 foreign bodies in, localiza- law of, 312, 313 tion. 102S Du bois-Kevmond'b, 312, function, desmoid test of, 313, 3S7 radiographs- in. 1029 monopolar, 331, 33.") electricity for, 13 ) motor points for, 335 hour-glass, radiography in, muscular, 335 1030 contraction from, 313, 335. infant, radiography of, 1029 See also Muscular con- nuliocinematograph vof, dan- traction. gers, 1033 in scries, 33ti radiographs- of, 1021, 1032, monopo ar, 335 1033. 1011 body, 31 1 Slid in 1 <'.~t Hies, i tion for, 1021 Cst posi- nature of excitability, 384 applied to desn oid test, peripolar, 33S 1029 tetanus from, 337 bismuth emulsion in, 1023, through unbroken skin, 335 ' 1021 tripolar, 33S meal in. 1021 nervous, 353 fixulst utTs passing through. application, 335 102s bv currents of brief dura- intensifying scree T in, 1033 ' tion, 315 iron oxi'd in, 1022 duration of, 3 Hi metallic emu sion in. 1023 Hoorweg's formula for, 3SS position for, 1021 1022 laws of, 3S7 technic, 1030 motor effects on stomach, zoolak in, 1022 350 secretions, elect riza tion and, nature of excitability, 334 350 peripolar, 33S ulcer of, .r-rav clia inosis of, reflex, 317 1025 s]iced of, 3-l(i ! Stomach-bubble, 1031 tripolar, 33s and induction coil for x-ray two successive, response to, work. 71S 313 care of, 102 wave of contraction and, charging of, 102 331 from alternating current , Weiss' formula for, 3SS 103 of cerebellar peduncles, 310 from direct cun cut. 102, of cervical sympathetic nerve, i 103 effects, 3!s, 319 rectifier for, 103 of facial nerve trunk, 3Sl> chlorid type, 101 of heart , 350 construction of, 101 , KH reflex, modified by poison.-, cooling of. while s i, Iding cur- ; > 5 2 rent, 1OO of median nerve, 3sii Kdi-on. 102 of myocardium. 352 l-'aure's, 102 of nerve-center, 352 tirids of, 100, 101 of phrenic nerve. 3xi', m multiple. Hit; of pneumogastric nerve, effect in parallel, lot; on, 319 351 in series, 1 do of sciatic nerve, reflex va.-o- dilatation from, 35O of spinal cord, 311, 352 peripolar, 33S pi unts of elect ion, 335 reflex, 3111 t rausmission of, i ime re- quired. 329, 330 t ri] ii ila r, 33s \'. i i--' formula for, 3xx Stini/iiiL r 's table of faradic ex- citability , UK) of neuromuscular excita- bility, 45li Stokes' theon of ,r-ra\ . i'i!i I Stomach, albuminoids' in, radi- ography of, lO2x atom of, high-frequency cur- rent f. i'-. tiO',1 carbohydrates in, electricity for, 130 radiography of, 1029 ;i iL-hl w in . n.:i:: dia-c d by dei trie IT, rent thnmgti, H'T netie pole-, 1 1 C nt. rnal i;-. . d7 I Stricture of esophagus, elec- lricit\ ior. 112 electrolysis lor, 122 radiograph v in, (I'.ll of lacrimal d'uct, electrolysis for, 122 of urethra, electrolysis for, 120 electrolytic dilatation of, 120 rectal, high-frequen<'V cur- rent for, (i!3 spasmodic, high-frecmenc\ current for, 5M String electrometer, Kintho- ven's, 175. 323 Strohl's method of localixat ion, MIS Student's resistance box, 232 Submarine cable, 235, 21s Substitution to test resistance, 22s Sudnik's high-frequency treat- ment of gonorrhea, 5S5 Sulphat- of copper as electro- lyte, !(1 of radium, 123!l radicle, liberation of, in vol- taic cell, SL' Siil])hur, effects on plates, VI3 Sulphuric acid a.- elei't rol\ te, i)0 Sun-bath in chronic infectious osteomyelitis, (i!U Sunburn, red lij-ht for, (isti Sunlight in treatment of tuber- eulosis, (i!U Superior maxillary sinus, radi- ographs' of, 981. See al-o Att'mm, ,aral\ ,-is of, 17s Surging currents for flat-foot, 1 10 electric apparatus, Morse's, 13!! Sweet's apparatus for localizing foreign bodies in eye, 90'.), !MO locali/ation chart, Weeks and Dixon's modification, !I1H localizer lor foreimi bodies in c; e, '.)()! I Switcii-board for electric bath s-urrent-, 13s Switclies, 135, 13ti, 21 is arcing a', prevent ion. 1 35 135 for condenser discharges, double-pole, 3X9, 390 knife. 13C, S\ i . -i-. elec'trnlysis in. Us hiL'h-trei|uet:cy eurreiit for, radium ra\ - in, 1270 x-ra> in, 11 75 > lunietrie gaiiLTeiie, galvani' ui-retit for, 127 Symphy-i- pubis, non-union of, 1( li ill tiurtnal, Hlon - paration of, Kir.ii . t,. ope, .-hLiroform, farad - urrent for, 12'.' i:oviti~, bipolar, d'\- current statie ij,d id .-n-s iii, 1 I 1-'. I 1 l:: iiifi:tni!ii:itiiiii <>! bunes, radi- um iphy in, 1 1 l:; rhino..c|eroma, j-rav in. I 17!' rinumnyi'liii, electricity fur. ['abeti" arthritis uf knee, iudin anaphoresis fur, 1(17 ' , radiography in. Ills I'alipe- ei|umu.-. radiography in. lust l'ani:ent L'alvanumeters, 1HO, I'M uf an-].-, nil ink development. s7H-xs] :pe. irisi.latim:. -Ml.' ippitiL' line fur additional nutlet, L'l:j irm i i >f jr-r:i.\ tube, li'.' 1 .', 7(K) !-! bones, fracture (if, ra'li- oj.'raph\ uf, lost. Ids.-, irsiis, radiography uf, IDS:', e-te. effect uf electricity on, result- in study uf muscular current-. -'s;i TI-I T :., i :-. it i' - I?:, fluuroscopy e;. -- a! roots, tuberculosis from, '.>'>''> , :. - of imperfect develop- mi-n'. I 1 ' 1 " . . u-tion . if, painli -s, 'i^ii fluon.-copy of. '.'17. S..<. ul.-o l>-" !'.<<"r ...... !:!. rial.- by . toplion -i- for, in.", iiii-n:pi.-il, : ; . ' >-' ; '] 7 ''I 1 ' i, .'iO_' 'I . ' . ' ' ' : .. , ....... ,;j| , : ' -:. Jl, moving r-liTtrolytrs outsiili- bat- tery, L'li'i in battcrii'>. L'lll cfTiM-i on m\-o(rrapliic diart, X I _' on rc.~i-tancc, L'L'I niii.-''u!ar contraction anil, :;x:i, :wi ii'-inini.'. '.is of cuiiihictini: wire-.. L'lM 'I'l-mpurary U-cth, railiuirrapliy uf. '.I.',:; 'IVndcrnc'ss, cutain>(m> an^a- uf. .'>( 1 1 Ti-nu-yiiuvitis, diathf-rmy fur, 037 Tcn-iun. Itiii rlectri' 1 . hydraulic pi'c.--un- and, comparison, 7^, 7'.i Tola coil, .Ml hijrh-froriuency apparatus, o."i] coil for .r-ray work. 7!_' current, .I'll applicatiun, ~>~>l type of portable j--ray out- tit, 7:-;:-; transformer, .'i.'>l <.'la.~s vacuum electrode eunnected with ]>u!e of, i.iiipi Jar ./"-ray tube. 77o \ acuum liplit', ii.")-', o.M Testicles, effect of j-ray oil, 1 1:, 1 ::il neuralfria of, .',1 1 TeMiiiL' for nerve injury, -I'll nerve at time of uperatiun, l.M Tetanic contraction for .-inu- soidal cnrri'iit.-, ! 11 Tt tarn;.-, electric, :-;:',( i c-xcitabilitx rif heart in, .'J.'il from low-tension current.-,-".! 1 reflex, :;i7 Tetany, l'.r\> reaction for, l~>7 . ~>~>~> Theory, Nenist'.-, :;:!! 'J'hermo-eleetric jiile, US thermometei . ( .'^ Thermo-eleetricit\ . '17 Thermographs, lifts r l"hc'nnoluminescen<-e, . \~> lllTIIIOH 'l el He, '^ I'heri ejrii' n.easurenn-nt ..' .r-ra\ .711 Therniup, :.. rial on, 1 1:11. S. . also l>:.i'>:.rn, l. \ at, . lei trie, I:--. on T-. niiei . |uei|i current for, ilu'M ! : nrl . irterie, ,,f, iadio(.nipli.\ of. 1 !.'. i! up\ n!', 111, I ' pi of. 1(17 J |,,.-. '- lateral plate- el . HI7.' rhiuMnamiii !oi keluid. C.L'S, ! 1 7', II rd nerve, paral.s -i- ut, 171 ,.!,.;-, I'.MI llie, 7'll I ' un p-un iluu-lun tura-e- ri'si-tance ot fralvanom- eter, j:;:i Tluirimn, !L'7'.i pure, etTective emanation., from, ll'.'.L' ra.\-, IL'H Thr.'lkeld-KdwardH devel,,|ier. SO" Thresliold of cuntractiun, Mr, Thumb, double, 10H7, Kills Th\ mus trland. hypertrophy of, j--ra\- in. 1 l^S Th\Tuid secretion increased by (iiathenn\ . l'iH5 Th\ roidectumy, effect upun ipi!i-ps\- induced hy stimula- tion, :i.'lll Tib:;i. fiacture of, radiofrrajihy of, 107.'i- 1077 uniun with malpusitiuu, radioi-raphyof, 107r,, 1077 Tic d' iiiluureux. See '/>"/'"'- inn! , ' :i Tin-fuil as screen fur .-uft ray.-, 71 is Tinea capiti.-, (lowers of sulphur in. 1 Isij reinfection from, 1 Isii .r-ray ill, 11s] of beard, .r-ray in, 1 1 s:i Tinnitu- auriuni, hi^'li-frc- (juency current fur, lil'.l Tintuniete-. r.ovibond-Corbptt, 1 1 :>s Ti-siies. anima!, elect rul> -i- of, L'H7. Sec also El<-ctrn!u*i* mat tixxiii*. am .-tint; seeundar\- ravs frum, choice of filter or cellular Biicky screen for, SHI chanties under static elei - t ricit y . 71 effects uf electricity un. -".'o influence un j--rays, s:-;:j usci'lator for iruut, r.ut fur obesit\ . i'ili:i for uric-ai'id cases, HOI Hanfeld, no:-! secondary rays aiisintr in. sUppre.-.-i i; in, lL'1'11 . M in, IL'O I'ul ' . 1H7 . . .. |>equenc\ ,|, I | !..r. OKI I 1,1,11 .'1 1m- l. ettiei,, and, .M I'urpur r. cti.ele.t'lii I INDEX Touch, sense of, effect of dec- Tousoy meth77 portable j--ra.\ t.utlit, 7:il hacking for radii, f raphie po-ition- for radiograph; plate, MiL' ( 'olles' fracture, ID'.IO bifocal tube for radiographs , j power of /-ray from vat bllie-lighl therapy with heat, ' precaution- in ca-e of break- Iis7 board eompres.-or in radiog- raphv of urinary calculi, 111.-,! I, in:, 1 [( llular diaphragm dangerous in renal radioiiraph\ . It >.".."> contact diaphragm, SOI dental flii.,ro-cope, C. (|iienc.v work, ~>\'.\ for attachment to tube riiuj, clo.scd magnet, 1_'O, lU."), stand, M-'Ct to JT-Tiiy tube. ^l\ u.-ed near or at ladietl to x-ray tube, sj.s screen, placed between patient anil plate, H2N radium applicator, anal\'.-i.- of radiation from, I -'17 Kit) to reduce trolle\--ear eurrent, _']."> rotary, 1J7 to 'reduce' trolley-car cur- rent, I'l") .-te])-down, 111.'. ]>;:',, 1C,.-,, 71X a.- rectifier, 10") step-up, IC.L', }>;'>, 7t:: current from, lliii for j'-ra\- work, I till elect rotherapeutic table. 1 !."> experimi'iit.- upon elect rir a' 1 - cidents, :;c,:; with solution expo-ed to radium rays, lL'('i7 film clip, !i:j.S !:.i. r close to plate for -up- ari-imr in tissues, v:-;il flui.ro meter, s| 1 frame applied to head to indi- rate median [.lane for -inn- radio.:rapli\ , !)77 for holdiiiu' [ilate in an in- il po-it ion for L'a-t unreel ified, as r-rav fenera- tor, 7 1M ventnl nibe- and. 1C,, for lii<,'h-frei|uency treat- \Vaite, , ~i() merit of rheiima- \Vapi)ler, 7."i() ti-m, C>()0 Transilkimination of frontal of -ciatica, .VI") ,-imis, !isl for i-olated l.e\'den jar Trari-illuminator, C'oaklev '-, .-park. l!i!i H>I for ront-renothe'-ap.v for ; Translucency, C,!)2 for j-ray application forleii- ' placements, 1070 kc'iuiii, 1 L'l T> Trail-plantation, excitability test of loss of detail in in- . after, 340 ten-it > intr screen-. Mill : Tran,-ver.-e ;irch of aorta, aneu- nte.-iiiial radiography, ' t liio-ina ruin treatment of ke- r\ -m of . radiography of, 1 1 K 1C, l(i::'.i loid. 117C, Trajx'zius, paralysis oi', 177 unit oi power, ll'lC, Tray development for dental and [|tiantit.\ . 1 IV.i , films, '.W use ill triple pha-e currents i Tfencli foot, adhesions of, static in an .r-ray generator, 1 1'> wave current- for, 71 vacuum electrodes, ot.'i, 'I'M Trianiiiilat ion. loealixation by, vertical liltn-currier, !C' '.'Oti, ti rad i iph of iliijrh, Io7_' ' " u-e altandoned ' b' au- thor. '.'.'1 mea.-uremi nt t ,1 ,r i:r, p, iwer, I 1C. I I_'C,II mi Iff - ml, li.",7, 1 I.V.I Ti-i. h, a, radiorr:i| e.|iiivali nt- o!, 1 lliD H I' 1 1 manenl dental ardi, !IUH, ,r. ills !Hi| Kroti a . ei Ian p f..r, C.V.I ol do-au'e in P : i liu-u" in. I Jill . ! J77 dcohol injection- for, .".o." Befconii'''- treatment . .',1 1 1 c-ataphoresis tor. .".(U cont inuous current for, .V i.", elei t ricitj for, .Mil , :,i i| di-tributii.n nt current, .VI.",, effect.-, ."id.") endodia-cope in, 77-' larailii i irrcnl lor, .Mi:; hiL'h-voltaire t teat merit , .",( 1 1 I.ediic 1 - treatment. .".(II aft. r, 1 I 1 ':; radium lor. .VI"., U7- inir c-ur- :-alic\lic ,-atapliof. inn 1C,C, I tvi -tatic dectri. in I r, .mi ' Tt'l -. !1- LiT.-iit, i.;j. ; -7 for pn.irn -sin inu-enlai l-Jll, 1C,:,, atioph ..",11 terrupl . IXDKX lOii by, disruptive nature of, (>,"il t libel cailar sera, ti7,X h\ dro-elee; rie bath-. 117 .r-ra\ . Sec l\<~uitiii ii-rm/ tttl'<*. (in ant is ciioms, (177 Tri|ile phase current-. 1 Jx ' Tubot ympanit is, elect ricits for, on bacteria, ti77 and ineeli:!nical move- l-il on chlorin, fiT'i incut, comparison be- Tumors, intrathoraeie, radi- on chlorophyll, (177 tweell, 1 Jx ovraphs of, 101!) on cobra venom, d77 in an j'-ras generator, . mcdiast irial, csophaL'cal ste- on colon bacillus in cul- Tou-es 's u-e ..:. 1'jx no-is from, radiography ture. Ii7! ll-c of, 1 J'.l ill, '.l!)"> (in diastase, Ii77 Tripolar stimulation, MX radiography of, 1010 (Hi dielectric liquids and Trollcs -ear current-, _' 1 1 (if bones, radiography in, 1 10~) solids, C,7(i circuit-breakers for, J17 of brain, radioirraphy in, !Klt on esc, li.xj for elect rot licra pent ics, Jl.~>, of joints, radiographs- of, 1 10.") on .rases, t',7.1 Jir. of him.', radiography of, 101(1 on human blood serum. rails, ground connection of, of neck, radiography of, !Ki."i (17,X L'lii of orbit, radium in, l_'7."i on inulin, (177 Trophic disease:-. hiuh-fre- of pituitary body, radiou.- on inscrtasc, Ii77 queney current for, ox:; raphs in. (M7 on micro-organisms, on \\assermann reac- abscess, (i,",:-; Turner's method of measuring tion for syphilis, (177 figuration f,,r, "ii'il 1 resistance of blood, M'.Hi erythema from, (177 irenito-urinars , hit:h-fre- 'l'o-f!uid tlicory of electricity. ers 1 hropsia from, (isl> quelicy current for. ox I 1(1 fixation of microbes b\ , C,x() hirh-fie,iuenc\- current for, T\ phoid -nine, radioirraphv of. fluoroscence^if, Ji71 :,7n. ."x'i, ii(i7 1017 for conjunctivitis, (ixS joint and skin, blue li./ln for conical ulceration, ti.xS treat nient for, i',x7 for facial neuralgia. 1 1!U lar.MiL'eal. mercury vapor tor locomotor ataxia, ti.xs liL'ht for, lixx 1 n HI; and cancer of stomach. tor lupus vultraris, (i7ii mercury vapor Unlit for, ()."io dilTerential x-ray cliaynn- for nciirit is, oOJ of bladder, hi^h-frequcncx -1-, lO-'.'i for scalp treatment, (iM cm '.-lit for, :,x! from radium rays, 1 L'."i7 for sciatica, ."i()S ol bone-, radioL'raph\ in, 1 1 JO hi;/ i-frei iiieney current for, for skin diseases, -1JS .;' -l fl . in, 1 1 Jx lij'" for sterili/al ion of milk, ot carpu-, radiotrraphs' in, of cornea, nil ravii.ilet rav for. ! 1 l.llji -. , hifh-l requeues 1 Ud'l ii it is fiom, ti.xS o(rrapi\ n, r:idinirrapli\ of, Kix'i I Ina; nerve para I \ -L- of, Ixii I llia\ iolet la, ,,|.. Haeli and It , I i'.K I ' lorl' , I'ilTard's modiliea- 1 ic in. ii7i ) ph>Mo!ocical ell', cts, l',77 positi\c and neyatue i.ms produced b\ . Ii7."i properties ot, li, ! i. st tor, r.7l' therapeutic use ot, C,7!t therapy, I'.'.HI lieatment by, . r i."il \\ ater I laiisparent In, t'.xll I n. lamped o.-eillations in dialh- eim . o::j. f.lo I ndeldevelopniellt, .XX7 I ndercxposure, de\-clopment in. IXDF.X I "ndcrexposure, development in, lank, x7'.i, xxo I'ndulatorv current for elec- tric baths, I !_' .if low |iotenti:il, I'.M) nature ot induced currents, I .v> I n. i ipted teeth, fliioroscopy nf, '.Us, '.Mil radiographs of, '.:,:: measurement, !l.">.~> I'nipolar .;--ra.\ tubes, 77:t, ll.'il I nit magnet ic pole, 17 I rnited States \:ilion:d Hoard uf l-'ire I 'nderu riters, regu- lations, of, 207 20'.l 1 'nn-et ilird t ransformer as .r-ray generator, 7 IM I'n-iaked lime as desiccator tor -latie machine, II) I "n-triated iiiiiscle, contraction of, :;:d I pper extremities, congenital le.-ions of, radio^raphv of, 10'. i:> fluoroscopy in. 10xC, fractures of, radioscopy of, 1 ( )! l,x paralysis nf, -177 radiography of, 10X(> Sclionberii's compression cylinder in, lO'.tl T'ranium, 'l27,x r:iys, ll'.'i'J. See also lirr.- ,,urrrl run*. rrhaiitschitseh's telephone tor ti'-t itlLC lleanilL'. I I '.' I'reter, currents of action in, :i27 radiography of, Kl'it I reteral calculi, fluoroscopy of, 1051 positions lor, !<)."> 1 iadio.;raphy of, HI.Vi, l().~i(> results, i()li() catheter for phlelioiith-. bl.'x in radic.m-aph.\, lO7,x I'rethra, electrodes for, :iK< external -phmcter of, spa.-m of, electricity for, I'-IO hifih-frequenev elec-tn.de- for, 5S1 stricture of, elect rolv.-is tor, oseop\ m. liCil lor. lO.'i I '. of, lll.'ili iu-r:ipli\ of, Kllx n band and mil. Hnble |,;IK for, 1 1 >:, 1 . ll)!i. luM I ToUM'.y'sinetliodoflocal- i/alion. ]U.',7 .r-ray 'or, ,">s7 I'rine, conduct ivil\- of, |M> ell'ect.- ol hi>;li-fi : e<|iieiic\ eiir- icut on, .")7."i incontinence of, electricity lor, -IL".) in neurasthenia, ol 1 '-' in rheumatism under liijrli- freiiuencv treatment, ti()() resistance of, M'.Ki I'rtiearia, static- elect rii-it\ for, 127 I'terine contraction from >lim- ulat ic m of r-pinal cord, .i I 1 fibroids, radium in, 1277, 1LI7S .r-ray for, 7U7 fihroiii'yoinatu, Tousey's tcch- nic of ronttri-notherapx' for, 12(17 r-ray for, 707 inflammation, Matic .-park for, 71 40") x-ray in, 1 _>:$() di>ea>es of, radium ra\'s in, electrodes for, Ms:l libromyoma of, Apo>toli treatment, l.'i.'! foreign bodies in, radiojrr.iphy nf, luiiti imperfect, >terility from, elce- trii-ity for, !:>:;' ret ro II, -\ion of, hydro-clee- li-ic- sitz-baths for, t 17 I 'viol lamp. i').~>:{, i)7_', r,7:i, r,7s for lupus, (is'.l leuree of, iinporlai in r- my treatment, I l-'iJ lectrode, I'.ix, t'.i'.l application throiiL r h e],,th- illL', ."l."l c . ', ol'p' I (fleets, local, ol'px for hiL'h- lre-|ii,-ir- . r, nts, .v,'j ,1,,-trn ! i handle for, .Vi't Iliah fre,|Ui-Uc\ . .Vt'.l partial, r,i:, perfect, l',."il re. !:n. i, I 1 for internal HM-, r,7 I mercur\ vapoi-, a.- double- curri-nl ivi-tific-r, lot po-it ivcl\ chained part ie|i in, 7l:i .-tatie wave current ap- plied by, (if, transmission b\ , disrup- tive nature of', li.M .r-ray s w ithin, 71 1 Vagina, endothelioma of, radi- um in, 1272 foreign bodies in, radioyra)ih\' of, KWili \'acinal electrodes, bipolar, :;s2, li.si; trlass electrode for hij.'h-1're- queney current, ."iM N'at'Us nerve, ]iaralv.-is of, (71 N'alve tubes, 7s7. See al-o \'rntril liilji:". Van't 1 lolT's lac-tor, 2oo law, :;i t obsei-vatioiis on soluble MI!>- tumors, el,-c-ti'ol\-sis of, tlli Vasoconstrictioli capillary, from hi(.'h-fn-i|iienc\ cur- rent, .-)7!> N'asodilatation. reflex. from si imulation of sciatic- nerve, :-',:>o \i<- p-hartri . 7xt;. 7x7 Villard, 7x7 \\ i-hiii-lt. 7xo '. rnal catarrh, ra.lium in. 1277 static \\ave current applii-d N'erntca. .-titaiihoresis for, -toil /h. i'.:. - - - lor, 1 1H 1 '-. "il.'i. .V)!) radium' for, ! Ix, rjnii I, ."iM ..-ra\ . 111! "-'''' r-r:ij for, II x. i I7x i ,c-ra; ' \i -. -. i. -.* : ;:..-. x.;7. , \'ersions' of uterus, hiirh-fre- n :- :''-. s., ;. x ; ( . s ;:,. \, ,",''.bne. ',','', 'vi'c'a ]."!-'.' " x|:; r -,dio i;raph\ . ,1 . W] -. x:;7 d.pf-. .rail 1 ! I, 71'. lumbar, radioyrai.h ' . Ioo7 ' ' ilator, low- r:iilii lt tr:i|ili> of, c\p,.- . lor, i- au'i .1' ele.-t ric it -. i hi- iijcli \'ertebrate>, i-lTeet - .1 - .!, HIT. ity on, Mill I, '-"-1 \ erfi i I'ulatoi tor Nitro Ken j i r, -07 I \. - - : .:-.', IXDKX Vc-ical calculus, hich-frc.iuency Voltajre of r-ray current, meas- Voltaic cell, voltage of, measur- -park I, >r freeini;, :>xi> uring, 7X1, 7:iS ing. 1)2, 1HX radiography of. lo.'iil. luill ozone production and, 4"i() volt-amperage of, XI, S.'i, SC, cn-i- in locomotor ataxia. physiologic effects of elec- watt.- of, X". calvanic current for. o 1 ."> tricity and, :>() I /.inc in, XH \'e-iciihti-. hiL'h-lrequcncy cur- reduction of, in j--ray work, consumed in, H,", Mill |. ,: . ,"iSti x.,11 couple, XH Vihrat ini; mierrupter-, x.",7 relation to capacity, in pro- currents, IS dec! romau'iiet ic. 111 ducing contraction, 1511) nature of, l.'.l. (Jlleen. So) to physiologic ctTects, 2H.", pile, original, H7 \ibrati,,n and taradic currenl telephone for measuring, 17s vert \t!<>, .'i'.).") loi , ibesit.% , Us unit ol, IH, 171, 172 Volt-amperage of voltaic cell. Vibrator for mechanic mas.-ace, Voltaic cell, S2 si, x:, xil oi 12 acid radicle of, S:i Volt-controller, 202 \ ibrat, ,r\- cm rent. ."12. See action of, x:;, xl i',|uid, 1 x| also Stulii- inin rurn nl. local, Ml Voltmeter, 170, l!i:i, 21H \ illard's in-trumenls tor mea. amperage of, Xl, So copj.er, 2111 urini; r-ra> . 1 I'll arc-lamps run b\ , 20.") d'Arsonvul's, 11)7 inlerrupter tor alternating; bichromate, HO ' electrostatic, 217 current-. s:,i, Biuisen, HI for r-ray work, 7XS lor tnpha-e current-, Soil cadmium standard, 1IU for r-ray work, 7XS, Sol) osino-rejrulator for r-ray cliarninn condciisi-r from, in -econdaiA circuit to meas- lubes, 7H1 2! 1 ure .r-ray dosage, 1 l.",7 t, , rai.-e \ aciium, s:;r, chemic action in, S2 measuring resistance b\ , 22H radio-clerometer for mea. chlorid silver of, 112, '.:{ silver, 21H uriiij-' penetration of .r-ray, Clark's standard, 112 static, to measure dilTerence si:; component parts of, XH in potential at poles ot \ ai\ c or ventril tube, 7H7, 7l IH condenser in shunt to, tube, Xlil ,,-ci||oscope connected W llll, chai'Kinfi from, 24 1 utilit\ of, 211) 7, Is Dan, ill, HI water, 2-11), 2.".0 Vent -il tub,, 7s7 l)e l.a Hue's, H.'i VolM >hm r-ra\ tube, 7(11 r-ra\ tube with accessory detail.- of various kinds, HI Vomit inn, h.vMt'oric, -ls:i electrode, 7l,H discharging condenser b\ , N'ulva, diseases of, electroU'sis \'illet'.- laradixation for chloro- 212 for, 12(1 ncope, 12H double-fluid, HI endothelioma of, radium in, Violet-rav from irla.-.- vacuum economy of, H."> 1272 electrodes, effects, o72 Kdi.-on-I.alande, H2 treatment, V.1 electro0 1 J7 Klemmjj-'- standard, H2 Walters' radiometer, Xt:{ \ ilreolls eli ctricitx . 1!) for cautery, xt;, xs \\ ajip'er interrupter, mterrup- Vocal cord-, pandysis of, 17.', for electroplating, Xll tions of, x.",l radiouiaph\ of, HHI1 for r-ray work, xii sinusoidal apparatus, Kill Volcker and l.icht, nbery's pye- gravity,' HI tiaiisfonner for r-ra\- work. phy, mi,.; ( Irovi . HI 7.",(l Volt, IH. itl'.l, 172 licat production by. H7 \\'ar injuries, physiotheratiy con, roller with mercury 1 ur- regulation, Xli, S7 and elect rodiajMio.-is in, 1 in, m'. rrupti r, 7J7 hi.-tory, H7 1.", 1 eli lor, d, ntal tract ional. hydroiren liberation in, s.'j l{,,ntt:en-ra\ therapy after, foi eataphore-is, In:, in multiple, si 1 isli, 1 1HO Volta contact -eric-, H7 in parallel, XI wounds, radiant liyht and e, H7 in series, si heat for. 11X11 induction-coil fed b.\ ar- \Varml h, wa\ e ol nci;ati\ e vari- ( : iTm'tiu, distinction, i:, rangement, 1 Is at ion and, 2so i'i, S. unit. 171. 172 operated b\ , .r-ra\ work Warts, diatherm\ for, (IISH , . 7- with, 717 electrolysis lor, III) jnl r.alandc-Kdi.-on, H2 flat, magnesium eataphoresis 1 . n of, 17 I.e Clanche, HI for. 1011 I'icto! - intluencinj/. :,n, :,1 local action of, Ml lunt'al inn, inacne-ium cala- i-. 2 M i j:, 1 magnetic properties of, 1 10 pholesis lor. 111(1 r.-ipeiil appli- maximum el!icienc\ , sr,. x, , hi^h-l'iei|uenc\ currenl lor, motor- inn b\ , 2(1.", i,2l ,' ! ". v '!, -,,- ope, : ,u, lt . eleetro!\lic cell, radium for, IIH, 12I1H ' ' ''7 1 part- of, XH '.; ra\ 'for, 1 1 s, 1 17s polari/.ation and, SI, ss Wasserman'n reaction, efTecl ,,t n , nl, J 1 7 pole- of, HO nil ra\ lolei ia; - on, i,77 inn nt. U'alch, irregular il \ ol, in power- , , ", hoe-, s, 2111. :;oi'i imp-, I'..',-, i, i lance in s,; Watei coiiihicl i\ u\ ot, JJs II;.; '10! : . |.">2 inductive, 'DM electrolysis of, 2JX , , t . , i :, j miei nal, HH e\ apora'tion of, electric chart',. tub, ,,1,,,, -j:i | and HI.", i, Hi i llowini- Hinnmli inclined o! latic i -hoii , ircuilint' of, HO nibe, inertia of, JI7 ; '-. , i chloiid, 112, H:', radileron.-, 1 2HH lec || ,id, HO baths in. 1 2HI1 -Inee. 'Ill n , .tance of, 2JS le-i-t H im di- lance of. ss static elect (icily compared , ,nd iid cell- t,, measure tlieri'iioini ler. 1 vollameler, 2 I'.l, 2.',O \\ at, i cool, ,1 r-ra.\ lube-, 7HI \\ atel jacket lube loi rectal \V:tll, Si. .S.'i, 172, 2OO \V'i'Stili)jhi)ilse-\erns1 lamp, ii7."i Woo.l. insulation o|, varni.-h fot U attinetef, 2OO Weston's <-lectromat'iH'tic gal- 21 2 Watts ..f dynamo, calculating, vanometer, SIH) point electrode, |:; 12:5 Wheatstcme hridw, 20(1 -plittmj;, static electrii if. of induction-coil, i:._', I .-).'{ equivalent, 2:;o from, .".1 \\a\e current, .">() for testing eonilnctivit \- of Wood's allo\, h;-.iiiL^point o> Morton, li:j. See al.-o SI'il- li.iuids, IS.') 21 1'. 1 {< inii'< nirri'iit. resistance of ^aU'anom- Work, definition, 171 stilt ic, li.'i. Sec also S/ntir eter, 2:J2 Workroom, ozone production uiirr nirn nl. measuriim resistance liv, tor, 11!) of conti-action, :0 2:!0 Wounds, r>um-tiin-il. infect. -d of low potential, L'7."). See to measure internal resist- with fistula-, copper cuta- also H'.in of ni't/ilticr r-tri- ance of voltaic cell, '.Hi phoresis for, I0r, ntiiin. Wheel interrupter, I'.ll shifuish, slat ic ele.-i i icit \ fi,r, of negative variation, 27~> with mercury jet and illu- 127 alternating relative po- minating nas arc sii]i- suppurating, md\-anic ftir- tential of, durum ad- ]>ression, ,s .->.-) rent for, -121) vances 277 t\i.c' of elect r.,niamietic in- war, phvsiotherapv and elec- cold and, 2SO terrupter, 1 1.'! trodiatrnosis n, l.".l. .M2 duration, 277 Wideninn of dental arch, bene- radiant lij-'ht at d heat for. fall and rise of, -'77 fi.aal elfect of, (Mil fiSli first, current durintr, 27d \\inisliurst static machine, :;:', \\'ri.-t, fluorosi-op-. of, Hlsr, forward progress of, 277 \\'ind, static electrieit\- from. fracture of, OilW, lai,,,i from reflex stimulation, .Jl radioyraiiliy of, 1001 :M7 Windint' secondarv coil, 117, radio|rrapli\' of, 10!l() in muscle, ~~~>, 27X, 2sd l.-.O l.->2 radio^rapliy of, Ills') in nerves, 27t>, 27.S ,r-ra\- coils, 1 .", 1 . !.",_' ' Writer's cram]), traK'ani.' r-tir- effect of narcotics, I'M) WindowH of dark room, S70 rent for, ;,]'.! fatijiue and, 2.SO Wire, 2IS \\ r\ neck, electricity for, old masking of, by superpo- carr\ IIILT capacity of, 22^> sition, 27S coils of, heatinir b\- current, point of origin, 2S1 222 processes takiim place conduct insr, heat ])roducl ion X \\-nil.l..\sMA, diathc>rm\- for, during. L'Sl rate of progress of, 2sl in, 221 'empera'ure of, 221 f '.'>: i Xanthin calculi, railioyraphx oi. relative potential of, 277 eoniliiction throutrh elei-- 10.".7 velocity, 2S1 troiles applied laterally, 2s:, Xanthoma multiplex, hiirh-tte- warmth and, 2SO copper. See ( 'n/i/n T inr, . (]uenc\ current for, Ii2:t Weber. 121) cross-sections of, I'l'.'l jr-ra\- for, Ii2d Weeks and Dixon's modifica- for coil, lenj_ r tli of. dctermin- .V-ray. See Roiituin-rny. tion of Sweet's locali/itiK inu', 220 chart, Dili number of turns, deter- AVehnelt cathode, 7i:i mining, 221 "\'ATKS method of treatinc deaf- interrupter, .",(1), 722, , 2:> natiL'es, 21s ness. i:;.'i efficiency of, l:ili in secondary roil, 1 17 'S'ellow licht, penetrating jH.uer in cutaneous applications, in.-u at ion of, 22:i. See also of, Iid2 :iso Inxnlntii.i, <,f ,rir,x. ^'ohimbin and protoveratrin. interrupt ions of, s.">.'j live, accidents from. :',77 studies of, in nerve stimula- parallel, rapid radiotrraphv metal, conduct ;vit\ of, 1' 1 H tion, :; 12 with, 711 resistance of, 21'.i, 22(1 variat ions in current with, rheostat, 2O1, 2O2 727 rubber-covered, 2Os .r-ra\ .wall installation with. ~ize of, 2IS /i I.I:N^ . current > lect r> i.-ei ip> i if. 7 in Win-N-sS teletirapliN , l.'iM, .V.I, 121o rectifier for alternating cur- .')(') 7 i Xinc, amal^an.ation of, for vo - rents, 72:> U'lrimr for installation of 1 Ill- taic cell. s:i \ elitril (lilies. 7sd volt direct current, 22l outside, 207. 20s for hemorrhage , ndome- nt' sciat ii':i, .V.l.'i toroinply with 1 . S. Xation.il tritis, 40s \\ i ;--' formula for M imulation, Hoard of I'ire 1 nderwritiT.*, for ulcer of let', ins .",ss regulations, 207 20: i cotisutned in voltaic cells, d.") lau of excitability, :{(."> \\ oltT's electroscope. L'O diaphraum, 7d 1 Welding, electric, si; Wood, acid-proving of, 21:', elect ri il\ t ic UK dient ion in \\ . Isl.ach licht for dark-room, hacking f<.r plat. . sp.i Koiiiirrhi a, !07 s7l) hall i-leetrnili . 1 Zirci>niun oxide in stomacl \\ i ; ti lu ;house electrolytic lurht- elect rode, hollow . Use i if, ti'.l radiography, 1021 tmm arrester, 227 iiisiilal ion of, 21 2. 21o Xo.,lak, 1022' THE LIBRARY UNIVERSITY OF CALIFORNIA Santa Barbara THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW. A 001 454738