BERKELIY LIBRARY or CAUKJBWA F*OM THE OPTOMCTRIC LIIHARY Of MONROE JEROME HIRSCH THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA GIVEN WITH LOVE TO THE OPTOMETRY LIBRARY BY MONROE J. HIRSCH, O.D., Ph.D. RKI! JRA A SYSTEM OF MATURE MEDICINE AS TAUGHT IN McCoRMicK MEDICAL COLLEGE CHICAGO, ILLINOIS FOUNDED 1893 CHARTERED IN ILLINOIS By Charles McCormick, M. D., President VOLUME I OPTICS and OPHTHALMOLOGY PUBLISHED BY McCormick Medical College Chicago, 111. 1916 / COPYRIGHT 1916 By Charles McCormick V. I Part I PHYSICAL OPTICS CONTENTS, PART I. NINETY-SIX ILLUSTRATIONS Preliminary Remarks . . 5 I. Refraction and Reflection by Plane Parallel Surfaces 13 II. Refraction and Reflection, by Plane Surfaces Forming Prisms 21 III. Refraction and Reflection by Single Curved Surfaces.. 29 IV. Refraction and Reflection by Piano-Convex Lenses . . 4-1 V. Refraction and Reflection by Piano-Concave Lenses . . VI. Refraction and Reflection by Bi-Convex Lenses 57 VII. Refraction and Reflection by B i-C o n c a v e Lenses 65 VIII. Refraction and Reflection by Meniscus Lens- es 69 IX. Refraction and Aberration o f Tri-Curved and Other Lenses. 81 X. Neutralization of Lens- es, Pres cription Writing, Transposi- tion and Analysis.. 87 XL Physical Construction of the Eyes, Stand- ard and Defective.. !>>'! XII. Physics of Retiryascopy and Why It Will Not W T ork Physiologically. .101 XIII. Exercises Involving the Principles . of Physical Optics 107 1.00 /.SO PRELIMINARY REMARKS. In the spring of 1895 I published a booklet of 100 pages entitled "Prac- tical Optics, for Beginnners," in which, after calling attention to the effects on the general nervous system from the efforts to overcome hyperopia, I concluded with the following paragraph : ''It is not unreasonable to assert that a very large per cent, of nervous 'diseases' may be absolutely cured without the aid of medicines, other than a pair of properly fitted spectacles." In 1898 I published "Optical Truths" in which I gave clinical experiences with epilepsy, female ills, and all sorts of nervous "diseases," explained how the nerve supply and demand could be measured, showed the fallacy of prisms as therapeutic agents, exploited the straightening of cross-eyes with- out operation and exposed ophthalmic charlatans and their practices. For all of which I was roundly abused by some of the so-called "authorities." In 1900 I began the publication of the "Ophthalmologist," a monthly, which was continued for ten years, in which I had the means of answering critics and spreading good tidings as I discovered them. In 1905 I published "Neurology and Metaphysics," a large, illustrated volume, in which were recorded in detail many discoveries beyond the field of Ophthalmology and the manner in which it was received was most gratifying. I still receive letters, almost weekly, from those who have tried out the propositions and found they all worked. In 1906 a second edition of "Optical Truths," rewritten and enlarged, was published and thousands of them 'are in the hands of practitioners who have expressed their satisfaction over its comprehensiveness, while the pub- lishers of "authoritative" text-books complain that the demand for them has "fallen off very much for some unaccountable reason." The fact that they are ambiguous and mere reiterations of one another is one of the reasons for this falling off in sales and it is highly probable that "Optical- Truths" has had much to do with it. In 1907 my "Synopsis of Neurology" was published, in pocket form, for the benefit of students and practitioners, and it has been called "the biggest little book" by hundreds who have written their appreciation. January 1910 the publication of Mature Medicine was begun as a quarterly "Circular of Information" to the profession and the public. Hun- dreds of thousands of copies are circulated every year and the results have been most encouraging. First, we have the evidence in letters from prominent laymen and physicians expressing appreciation of our outspoken 6 A SYSTEM OF MATURE MEDICINE efforts in enlightening the public generally and themselves in particular ; sec- ond we have incurred the hostility of the Medical Trust, which is interested in keeping the public frightened, the Newspaper Trust, the Religious Trust and the Political Trust, all of whom are allies of the Medical Trust, and they have slandered, ridiculed, "investigated," "exposed," "legislated" and other- wise discriminated against us, all with about the same effect rain has on a duck. All of which reminds me of the parable of the wise man and the foolish man who builded their houses upon a rock and upon the sand. See Matthew VII, 25-27. This book is the first volume of a review of what I have gathered in the past twenty-five years from practice, teaching, writing and applying myself to the study of things as they are, instead of as self-styled "scientific authori- ties" would have us all believe. From my past experiences I am as s.ure of a welcome for the work as I am sure of the pleasure and more substantial benefits in the preparation of the copy. My work was begun because of the false pretenses of the old schools of medicine and other sophistical sects and their antagonism has been my constant inspiration aided and abetted by my own enthusiasm over the truths I have found and proved. Many years ago I asserted : "Nervous strain, through defective eyes is the Primary cause of at least eighty-five per cent, of all human ills." I have never had occasion to recant. On the contrary, the opprobrium heaped upon me by my contemporaries spurred me to pile up the proofs, which I did so effectively that one of my friends, the enemy, later asserted that "eye strain is the Cause of eighty-five per cent, of all ills." His assertion was accepted as true, because he had an "international reputation" as a compiler of dictionaries. The statement is obviously false, while I shall show that my reference to it as a primary cause is rational ; and I will also show that no system of eye practice is complete until it embraces a theoretical and practical knowledge of the secondary, or contributing causes, how they may be pro- duced directly and indirectly by the primary cause, how they may be prod- ucts of habits, occupation, and other voluntary conditions, or from those over which the individual has no control. It should be apparent to anyone that if a nervous system is depleted from any of the following causes : con- genital, infection, malnutrition, physical shock, mental shock, physiological strain, mental strain, habits, occupation or atmospheric influences, or a com- bination of two or more of them, the correction of the physiological demand through the eyes would not be sufficient to restore physiological equilibrium, even if it affords partial relief to the afflicted. It is my purpose to cover not only that part of physical optics which relates to the practice of ophthalmology, and do it a little better than it has ever been done before, but to go into considerable detail with reference to the origin and exhibits of the contributing causes, together with methods of procedure in the measurements, charges, discounts and analysis of all sorts of symptoms, mental and physiological. INTRODUCTION The query "What is light?" has agitated the brains of investigators for many centuries, yet it is still an open question in some particulars. There have been exploited three theories of light: (a) The Emission or Corpuscular, in which, it was explained by Newton, to consist of "elastic particles of inconceivable minuteness, shot out with in- conceivable rapidity by luminous bodies." He justified his' belief by the facts illustrated in reflection and transmission of light with reference to transparent materials, such as glass, and by the luminosity of any solid body when heated ; as the heat radiated so did the light ; the latter being perceptible at a greater distance, signified a different property. This theory did not ex- plain what light is nor did it explain phosphorescence, nor other exhibits of luminosity, and after it dawned upon the world that Newton was not infal- lible, the theory was repudiated. But that does not prove he was wrong. As a substitute, a theory by Thomas Young, an Englishman, born in 1773, was adopted after much acrimonious bickering among the scientists. (b) The Undulatory or Wave theory propounded by Young and gen- erally accepted is that "when, under certain primary conditions, a disturbance occurs in the 'ether' light is promulgated in the form of infinitely small waves, up and down." (Just what "up" and "down" is in universal space he did not tell). This theory has been elaborated by others, who noted sound waves and those caused by dropping pebbles in the water until plausible explana- tions of many light phenomena became popular. (c) Then came the proposition that "Light is really in the nature of a periodical electro-magnetic polarity of the luminiferous ether." It is gen- erally passed because it is too indefinite. Many experiments with light have been made. Newton found it to be a composite by developing colors in passing light through a prism. Then the wave theorists declared the reason for the existence of colors is because: "Light which emanates from the sun, and, indeed, from any incandescent body, is not of one wave length, but is composed of a confused mixture of waves of every length down to a limit fixed by the temperature of the luminous body and that differences of wave lengths affect the optic nerve so, as to produce a sensation of difference in color." To illustrate, they take as a unit the 10,000th part of a millimeter, then, "light of wave-length 7 units will appear intensely red ; one of 6 units will be salmon-yellow ; 5 will be green ; 4 blue ; less than 4 it will be invisible." This reads fairly well ; but there is a discrepancy which no theorist has ever explained. Possibly they have never observed it: Chemically glass be- longs to that large class of combinations called salts, it being a mixture of two or more silicates. When silica, or silicic acid, is combined with a base, such as calcium oxide, or lead oxide, a silicate is formed. The most common kind of glass is made by melting together silica in the form of sand, lime-stone, or calcium carbonate, and sodium carbonate, or soda, the product being a silicate of sodium and calcium. The sodium may be replaced by potassium, either partly or entirely, and the calcium by lead. The propor- tions for the different kinds of glass have been established by experiment. A peculiar difference in the action of glass on light is found when lead is sub- stituted for calcium. The index of refraction remains almost unchanged but A SYSTEM OF MATURE MEDICINE the capacity for dispersion is almost doubled, therefore the dispersion of a 20-degree prism of calcium glass may be neutralized by a 10-degree prism of lead glass, bases opposite, while the refraction of the calcium glass is only half neutralized. It is this chemical property which facilitates the manu- facture of achromatic lenses. The point which has been overlooked by the wave theorists is that it is evidently not the mechanical structure but the chemistry of the combination of prisms which disperses and reunites the colors. This is the basis of our theory of color blindness, which subject will be treated in its place. Thus the wave theory gets a blow in the solar plexus. Tyndall wrote : "No human authority, however high, can maintain itself against the voice of Nature speaking through experiment." He was referring to Newton's theory and to the sarcasm of Mr. H. Broughan, in the Edinburgh Review, against Young, which prevented the acceptance of his wave theory for more than twenty years. In view of the discrepancies in all of the theories so far advanced, when put to severe tests, we have evolved the following definition of light as a matter of convenience and comprehension in introducing the subject to the student: The word light refers, physically, to anything, Natural or artificial, which renders objects visible. Regarded as a substance, it is a product of chemical or mechanical agitation, whether it comes to us in the form of in- finite atoms or otherwise is of no moment in the practice of ophthalmology. Natural light is an infinite product. Its influence on planetary develop- ments, on their movements, on plant and animal life, is beyond human comprehension. It exhibits most vividly in sunlight ; next in importance, probably, is lightning; then the vital brilliancy of the fire-fly, glow-worm and other species; finally the phosphorescent luminosity of decaying matter. Artificial lights are finite products, beginning with the torch of the aborigine, followed by the tallow dip and other oils ; then the gas period ; now electricity. The possible products of chemistry and mechanics are almost limitless. The purposes of this book confine the author to those facts which are demonstrable beyond question; hence speculation is left to those who choose mystery over mathematics. It is not intended that it shall be a popular book. It is hoped, however, to make it a work that will help some people to think and encourage them to persist in their efforts to help themselves and others. It shall not be a dry or cold book. It will, probably, be hot in places. In teaching we believe simplicity and directness are indispensable to comprehensiveness. In all of the twenty-three years of school work we have practiced this belief and -the results have been satisfactory. A teacher must get close to his pupils. Few dare do this because of a fear of the "familiarity" which "breeeds contempt." Experience has taught us that the student who grows contemptuous when his teacher appears to recognize him as human, is not of a calibre to be feared. The laws of refraction, as well as other matters, will be presented in consecutive order. No attempt will be made to be artistic in text or illus- trations. The latter will fit the former, and the student who reads should measure to be sure of an understanding. INTRODUCTION Systematic study is the only method by which one can attain competence in any line of work. Nature does things on a fixed plan and if we follow it as nearly as pos- sible we will acquire information more easily and completely. I have named the method I employ the duality system. I often use an apple in illustration before a class, dividing it in halves, then placing the halves together, turn it half around and make a second division, vertically, at right angles with the first cut; then, putting the four pieces together and turning it on its side, another cut through the middle makes eight pieces. As no other single cut will double the number of pieces again, it is a good illustration of the limits of laws and suggests that when we have reduced any subject to eight parts by the duality system, we are in a fair way to get all there is to it. The same subject may be subdivided in different diagrams, and it is often ad- visable to do it, because of the possibility of making mistakes in classifica- tion. The following specimens may help the student grasp the idea. He will never master it absolutely. I never have attained and do not think it possible for anyone to attain perfection in it; but it is a wonderful help and is as interesting as a game of chess : Natural. r Composition ..... ) Color Optics. Light. Artificial. Positive. Refraction. Negative. [ Vitality { Physiological I Metaphysical rAncient ( Torch J I Oil \Modern (Gas I Electricity r Simple.... (Transmission \ Reflection I Compound ( F ci ( Aberration (-Regular ...(Spherical J ( Cylindrical I Irregular ( Design ( Accident Then we take each word and investigate it in search for suggestions, thus: Optics is a branch of scientific study which treats of Light and Refrac- tion, from simple principles to Astronomy, physically ; to Ophthalmology, physiologically ; to General Knowledge, intellectually ; and to Health and Happiness, compositely. Light is luminosity, either direct, from luminous bodies, or indirect, by reflection from objects not luminous; it not only enables those who can see to do so, but it has an influence on the growth of vegetable and animal life, and is the greatest aseptic and antiseptic known. Natural light comprises sunlight, lightning, phosphorescent glows, and the physiological exhibits of some bugs, worms and birds. The composition of natural light is a combination of elements repre- sented by colors red and green, yellow and violet ; the first and second are 10 A SYSTEM OF MATURE MEDICINE complementary to each other and the third and fourth bear the same rela- tion. The spectral colors are products of these four. Vitality of light is that physical and metaphysical influence which affects life and mental moods. Artificial lights lack many of the qualities of the natural, but they offer evidence of mankind's capacity to imitate Nature and afford means of con- tinuing work during hours when the natural facilities are supplying our neighbors on the other side of the earth. Ancient artificial lights were the torch and oils probably ignited with a flint and steel. Modern artificial lights, gas and electric, are testimonials of the ad- vancement of the race. Refraction of light is the change of direction by means of transparent mediums presented at proper angles so that the change occurs during the passage of rays through it. Positive refraction is a subdivision of the subject for convenience and means that the change of course is in a certain direction, nearer the per- pendicular to the refracting surface. Simple refraction refers merely to the changes in course during trans- mission or by reflection from a surface. Compound refraction includes the focusing of many rays at a point or a line, or sending them away from a medium as if they came from a point or a line; also the 'chromatic and spherical aberration which is associated with refraction. Negative refraction is a classification directly opposite to the posi- tive. Regular refraction is that accomplished by spherical or cylindrical sur- faces by transmission or reflection. Irregular refraction is that which occurs by accident or design such as may occur in broken glass in the alley or in the diamond faceted by expert workmen. I have purposely given in the diagram subdivision to sixteenths; but have only made fifteen paragraphs covering Optics and its fourteen sub- divisions. The other sixteen words in the last column are merely for sug- gestions in defining the ones covered in the paragraphs. It is worthy of mention that the fourteen subdivisions of the subject "optics" are as many as the elements known to be necessary in the composi- tion of the human body. f Fundamental.... .. / Physics Theory ( Technical.... .. / Mathematics \ Physiology Ophthalmology ( Symptomatology / Objective Practice Subjective Analysis.... - / Dynamic \ Static Ophthalmology, considered properly, comprises not merely the study INTRODUCTION 11 of the eyes and their appendages: it includes the nervous and circulatory systems, the digestive and egestive apparatus, and all of the body functions, with especial reference to the manner in which nerve strain through the eyes affects general physiology and how reflexes from such affections return to the eyes. Theories are worthless unless they are founded on sound principles. Many of the errors of the old-school practitioners are easily traceable to wild ideas in which the wish is father to the thought expressed. Fundamental means a leading, or primary principle, which serves as the ground-work of a system. Physics is the science of Nature and covers the study of material things. After which we may be able to form rational ideas of subjects which are confined to the realm of speculation. Ages ago Aristotle coined the word "metaphysics," which means "after physics." He was the great agnostic of his time, a true philosopher (lover of truth), hence not at all popular with the bosses who found it to their advantage to keep the general public ignorant. Anatomy is the physical study of the body, its composition and arrange- ment. The manner in which it is taught in the old schools yields compara- tively little information and their students with whom we have come in con- tact were lamentably deficient in practical knowledge. Technical means, literally, "to bring forth ;" therefore it becomes a necessity in the study of any subject to go into great detail; yet excessive technicality may be confusing to the student and good teachers avoid it. Mathematics, as expressed in simple arithmetic, affords abundant facili- ties for instruction in all business and professional work, and the most suc- cessful men and women in all lines have limited themselves to it, excepting departures for special purposes or for entertainment. Physiology is the reason for anatomy, expressed in one word. In my school we teach anatomy, physiology, pathology and therapy all at once. It interests and instructs students, and they do not forget. Our work is so in- tensely attractive that neither teachers nor pupils are ever late in assembling. Practice is the putting into action the knowledge acquired by study, and those who have learned the principles of their profession thoroughly cannot fail to be enthusiastic, successful practitioners. Symptomatology as taught by us is as different from that of the old schools as could be imagined. Briefly, we teach what constitute symptoms of normality and that any departure therefrom indicates a necessity for prompt and vigorous action ; our proposition is based on fundamental facts. Others teach an alleged symptomatology which is purely empirical and, while rational, within narrow limits, is often positively wrong, hence mis- leading. Objective symptomatology is that which is exposed to us macroscopical- ly and microscopically. The ophthalmoscope, combined with the dioptric system of the eye, becomes a wonderful microscope. Subjective symptomatology is that which is developed by questioning patients and considering such information in connection with what we know from our training and experience. A SYSTEM OF MATURK MEDICINE Analysis of a case involves the consideration of the details of an ex- amination, separately and as a whole; it enables us to proceed with cer- tainty in practice, while "diagnosis" means working by guess, which is, to say the least, very uncertain. Dynamic means force. Any test which requires a patient to exhibit his physiological powers is dynamic and we have some very practical yet ab- solutely harmless ones. The Neurometer is based on these. Static means natural. We have such tests, which we employ to sub- stantiate or refute the dynamic showings. They are a part of the Neuro- meter, which is not a machine, as many have supposed, but is a series of tables which we employ in making analyses of cases. For general study we have the following as a fundamental proposition : f Inorganic ..................... j Water f Chemistry ! ] Salts ( Organic { Fats Mathematics <( ( Carbohydrates f ,Form.... - I Regular } Irregular Mechanics. Motion 5 Systematic Locomotor Mathematics suggests accuracy, consecutiveness, thoroughness, law. Chemistry relates to the composition of matter and the changes it un- dergoes. Inorganic chemistry is the science which treats of elements and their properties. Water, salts, air and light. Organic chemistry is the study of the composition of the structures of plants and animals. Fats and carbohydrates chiefly. Mechanics treats of the action of forces, statically and dynamically; light, gases, liquids and solids. Form covers a division of mechanics relating to architecture, and an- atomy. A form may be regular or irregular. Motion is physiological mechanics with the duality : systemic and loco- motor. If any subject be skeletonized in this manner it conduces to satisfactory analysis and ready understanding. In the preparation of copy for this work I have received much! valuable assistance from my colleague in school work, William L. Black, M. D., which assistance is hereby acknowledged with gratitude. THE AUTHOR. Chicago, July 17, 1916. N. B. Some of the results of calculations are expressed in mixed num- bers and some in decimals for the purpose of instructing students in arithmet- ical gymnastics. Some of the decimals are carried out farther than others, for the same reason. The chief object of the work is to teach principles. Common fractions are absolute; decimals are approximate. CHAPTER I. Refraction and Reflection by Plane, Parallel Surfaces. Following is the composition of four kinds of glass: 1. Sodium' Glass: Window, plate, table and bottle glass; sometimes called soda-glass, or soft glass, to distinguish it from potassium-calcium glass, which is hard. Formula: 2Na,Cp, + 2CaCO s + 2SiO 2 = Na 4 SiO 4 + Ca 2 SiO 4 + tCO 2 Washing Lime- Sand Sodium Calcium Carbon Soda stone Silicate Silicate Di-oxid The CO, bubbles off and the remaining mixture of sodium silicate and calcium silicate solidifies on cooling. 2. Potassium-Calcium Glass : Bohemian crown or hard glass is used largely for chemical glassware, because it is not so easily attacked by many reagents and withstands greater heat without softening. Formula: 2K 2 CO 3 + 2CaCO s + 2SiO 2 = K.SiQ. + Ca.,SiO 4 + 4CO 2 Potassium Calcium Silicon Potassium Calcium Carbon Carbonate Carbonate Di-ox. Silicate Silicate Di-ox. 3. Sodium-Lead Glass : A mixture of lead silicate and sodium silicate. It is softer and melts at a lower temperature than plate glass. Flint and cut glass come under this head. Formula: 2PbO + Na 2 CO 3 + 2SiO 2 = Pb 2 SiO 4 + Na 4 SiO 4 + 2CO 2 Lead Sodium Silicon Lead Sodium Carbon Oxide Carbonate Di-ox. Silicate Silicate Di-ox. 4. Potassium-Lead Glass : A mixture of potassium and lead silicates. It gives a variety of flint and cut glass. Formula : 2PbO + 2K,CO 3 + 2SiO 2 = Pb 2 SiO 4 + K 4 SiO 4 -f- 2CO 2 Lead Potass. Silicon Lead Potass. Carbon Oxide Carbonate Di-ox. Silicate Silicate Di-ox. Refraction means "to break." Refraction of light is the deviation in its course a ray suffers in passing, obliquely, from one transparent medium into another of different optical density. Chemistry and Mechanics constitute the duality of causative factors which result in refraction. Chemistry is represented in the composition of the material. Mechanics, in the form of the mediums. An Index of Refraction is the expression in figures of the Optical Den- 14 A SYSTEM OF MATURE MEDICINE sity of different transparent mediums compared with an agreed standard. Air, compared with a vacuum, has the index 1.000294; but, as air is the most common and rarest of all practical mediums, it was selected as the standard and other mediums have their indexes based upon it. Optical Density differs from mere compactness by representing the rela- tive resistance offered to the passage of light through different transparent mediums. Following is a table of indexes of various mediums : Hydrogen ._ 1.000029 Flint Glass 1.57 to 1.64 Air 1.000294 Optical Lens Glass 1.523 to 1.64 Oxygen 1.000272 Ice 1.31 Nitrogen 1.0003 Rock Crystal 1.562 Carbonic Acid 1.000439 Diamond 2.50 to 2.70 Water 1.33J Cornea and Aqueous 1.3365 White of Egg 1.351 Vitreous Humor 1.3365 Human Blood : 1.354 Crystalline Lens 1.4371 Canada Balsam 1.523 Same, compared with ' sur- Sea Salt Solution 1.375 rounding media 1.0752 Crown Glass _ 1.50 Index of eye as a whole 1.52198 The Index, or Optical Density, is, inversely, the relative rate of speed at which rays travel in the several mediums ; the denser the medium the slower the speed. Thus, the rate of speed at which light travels through air is 186,000 miles per second ; crown glass, with an index of 1.50, would offer 50 per cent more resistance, hence the rate of speed in the glass would be only two-thirds of that in air, or, 124,000 miles per second. To find the index of one medium compared with another when the in- dexes of the two, compared with a standard, are known : Divide the greater- figure by the lesser, because this keeps the rarer medium the standard. Index makes possible the location of courses of sections of rays before, during and after the passage through given mediums, by enabling measure- ments to be made of the angles formed with the perpendiculars to the .respective surfaces at the points where refraction occurs, because all measure- ments are predicated upon the resistance offered by the denser medium. Attraction is a better word than density to employ when the deviation of rays is being considered. The amount of refraction is regulated by the angle of obliquity at which a ray approaches the surface of the dense medium and by the density or chemical attraction thereof. The first is an inconstant and the second is a constant with respect to all mediums. In the definition of refraction, at the beginning of this chapter, the word "obliquely" is of particular significance, because, if a ray approaches the second medium perpendicularly to the surface, that is at right angles, it will pass through without change in its course, suffering only from reflection and absorption. The reason for reflection is that the amount of light ap- proaching is much greater than can be passed, hence the surplus is repelled at the surface of the dense medium; absorption occurs to such an extent that unless the light is very strong it will not penetrate even air any great distance. This is the reason a light from a lamp cannot be seen from more than a mile or two on best nights for the test, that is with clear atmosphere. The reason for breaks in lines representing rays, at the surfaces of mediums, is that being of different optical densities they have different at- REFRACTION BY PLANE SURFACES tractive powers, so that a ray in passing obliquely from one transparent medium into another of greater density, or attractive p^wer, is drawn toward a perpendicular erected to the surface at the point where the break occurs, making the angle formed by the refracted section and the perpendicular as much smaller than that formed by the approaching ray and the same perpen- dicular as the index of refraction of the rare medium is smaller than that of the dense and, on leaving the dense medium for the rare, the action is reversed, because the attractive force of the dense medium is withdrawn. The first deviation is positive refraction and the second is negative refraction. In the latter instance the angle formed by the emergent section and the perpen- dicular is as much larger than the angle formed by the ray in the dense medium with the same perpendicular as the index of the dense medium is greater than that of the rare. Students should note the entrance of Nature's duality system at the be- ginning and become familiar with it, because it will be found conspicuous in all departments of this and other studies. We shall employ it frequently and even carry it to the extent of diagrams, splitting subjects into halves, quarters, eighths, and sometimes even to sixteenths and thirty-seconds. It is a part of our scheme of consecutiveness. Fig. 1 is made on a half-centimeter scale. It should be studied carefully, because it illustrates the first principles of the laws of refraction, without a good working knowl- edge of which no one can ever hope to be- come a competent ophthalmologist. It is a deplorable fact that very few of the most pretentious oculists and opticians know any- thing whatever about these fundamentals. They often proclaim themselves by de-. nouncing others as "quacks." The lines marked R', R 2 and R 3 are, re- spectively, the incident, refracted and emergent sections of a ray passing from air into glass then into air again. The course of the incident section is toward C', but, as it approaches obliquely, it is refracted at the first surface and its new course is found by measuring the angle of incidence at a convenient point, as indicated by the scale, and marked If on the upper horizontal line; then, continuing it across the vertical line, P', to PI', and marking the short end 1. These two sections of the horizontal line bear the same relation to each other that the indexes of the two mediums do. From the end of the line 1 the vertical line, PI' is dropped, parallel with P'. Now measuring the distance from O, on the incident section, to the point of refraction, and dupli- cating that distance obliquely toward the line PI', it will locate the point where the refracted section will cross, thus giving its course to the other surface; the dotted line from x' marks the angle of refraction, 1.00, which is 16 A SYSTEM OF MATURE MEDICINE to the angle of incidence, 1.50, as the index of the rare medium is to that of the dense. The refracted section, R 2 , strikes the second surface at the line P 2 and the first proceeding is reversed, the horizontal line from R 2 , crossing P 2 , has its short end, 1, on the right, and its long end, 1, on the left of the line P 2 . Dropping the line PI 2 parallel with P 2 , then measuring the distance on the refracted section from the horizontal line, 1, to the point of refraction and measuring the same distance, obliquely, to PI 2 at the dotted line, x 2 , locates the point where the emergent section will cross and its course, R 3 , toward C 3 , parallel with the original course of the incident section. The angle of emergence is to the angle of refraction (the angle in the dense medium), as the index of the dense medium is to that of the rare. A is the angle of incidence ; B the angle of refraction ; E the angle of incidence to the second surface, also known as the angle of refraction, because that is what it would be if the ray approached from below; F is the angle of emergence. In refraction by plane, parallel surfaces, the angles of incidence and emergence are always of equal size ; the two angles in the dense medium are of equal size; the relation between the lesser and the greater is always that of the index of the rare medium compared with that of the dense. The angle formed by the reflected sections of rays with the perpendiculars to the surfaces is always of equal size with its angle of incidence, no matter what the index of refraction may be, and the reflected ray always passes away on the opposite side of the perpendicular. The method of making measurements, illustrated in Fig. 1, I have named the Perpendicular-Parallel method. After establishing the fact that in refraction by plane, parallel surfaces, the emergent section always parallels the course of the incident section, the last half of the method might be omitted and the course finished arbi- trarily ; but then there would be no proof that the first part of the drawing is correct ; while if, by measure- ments, the emergent section takes the course we know it should, the work is proved. Particular attention is called to this point because no method of practicing anything is cor- rect until the practitioner knows four cardinal principles : First, what he wants to do.. Second, why he wants to do it. Third, how to do it. Fourth, how to prove it. Fig. 2, \ cm. scale, shows another way to construct Fig. 1. In this, after measuring the angle of incidence at A' and dropping the parallel, PI', the point of refraction is taken as REFRACTION BY PLANE SURFACES r the center of a circle from P' through the incident section at A', where the angle is measured, to B', which locates the point where the refracted section will cross PI'. Then after erecting P 2 , measuring the angle at A 2 and drop- ping the parallel PI 2 , the point of second refraction is taken as the center of another circle from P 2 past A 2 to B 2 and the point where it strikes the line PI 2 is the course of the emergent section, R 3 . This may be used in- dependent of the parallels to perpendiculars, by merely measuring the angles of incidence to each surface and making the circles of indicated radii, then measuring on the circles as indicated by the dotted lines at B' and B 2 to get the angles of refraction and emergence respectively. I have combined the methods here to show how one proves the other. Fig. 2 illustrates the Circle method, as well as the Perpendicular Parallel one. Fig. 3, 1 cm. scale, shows a very simple way to find the course of the refracted section, etc. I call it the Chord-Arc method. After erecting the perpendicular, P', at the point where the incident ray strikes the first surface, and measuring the angle of incidence at a convenient place, C' ', take the point of refraction as the center of a circle of which A' is the arc ; then divide that half of the chord marked C', which measures the angle of incidence, so that when measured from the perpendicular toward R' the longer portion will be to the full length of the line C' what the index of the rare medium is to the dense; erect a perpendicular to strike the arc at A' ; then draw the line represent- ing the refracted section as if it came from A', proceeding in the At the second surface erect the perpendicular P 2 , measure direction A 2 , the angle C 2 from P 2 to A 3 , the full length of the line between P 2 and A 3 being to that portion between P 2 and R 2 what the index of the dense medium is to that of the rare; then, taking the point of refraction as the center of a circle of which the curved line from Rfl 2 to A 3 is the arc, and drop the short vertical line at A 3 from the line C 2 to the arc to get the point from which the emergent section R 3 appears to be directed. A portion of each ray is lost by reflection at each refracting surface, (Rfl' and Rfl 2 , Fig. 3), the angles formed with the perpendiculars by the reflected sections being exactly the same size as the angles of incidence and always on the opposite sides of the perpendiculars, regardless of the difference in in- dexes of refraction of different mediums. The amount lost by reflection increases with increase in the size of angle of incidence until, when the 18 A SYSTEM OF MATURE MEDICINE latter is about 50 degrees, there is total reflection so far as optical purpose is concerned. This is called the limit angle. The indexes of glass used for optical pur- poses are various and nearly all are expressed in figures which do not work well in making drawings such as Figs. 1, 2, 3. It would be difficult to measure 1.53 and other smaller divisions than halves, quarters, etc., so neces- sity spurred me to devise easy methods. One is presented in Fig. 4, and I have named it the Base-Line method. R 1 , R 2 and R 3 are, respectively, the incident, refracted and emergent sections of the ray. The line BL' is the base-line for finding the course of the refracted section. It is placed on the right and below R' because we know the break on entering the denser medium will be toward the perpendicular X'. This line, from the point of refraction to O' is 10 mm. long; and this distance backward on the base-line toward the first surface, marked O 2 , is the point to measure from after a calculation. Rule: The perpendicular, X', multiplied by the index, 1.50, and the product divided by the excess index, .50, will give the distance from O 2 to F', the point toward which the refracted section will be directed. 10x1.50 = 15-f- .50 = 30 mm. from O 2 to F'. The line BL 2 is the base-line for finding the course of the emergent section. It is placed on the right and*above R' because we know the break on leaving the denser medium will be from the perpendicular X 2 . The line, from the point of refraction to O 3 , is 8 mm. long; atid this distance forward on the base-line toward the second refracting surface, marked O 4 , is the point to measure from after another calculation. Rule : The perpendicular, X 2 , divided by the excess index, .50, gives the distance from O 4 to F 2 , the point on the base-line toward which the emergent section will be directed. 8-f- .50 = 16 mm. from O 4 to F 2 . It is one of the principles of refraction that the reduction in size of angle, on en- tering a dense medium from a rarer one, is less than the gain on leaving that medium. With an index of 1.50 the loss on entering is one-third and the gain on leaving is one-half. From these facts the rules given were made. Fig. 5 shows another simple method of finding the courses of the refracted and emergent sections. R', R 2 and R 3 are the incident, refracted and emergent sections of the ray. P is the perpendicular to the sur- face at the point of first refraction. REFRACTION BY PLANE SURFACES 19 . Rule: The distance from 1 to 2, multiplied by the index, gives the dis- tance from 1 to 3, from which point the refracted section takes its course. The distance from 3 to 4, divided by the index, gives the distance from 4 to 5, from which point the emergent section takes its course. I have named this the Single Perpendicular method. It and the Base- Line method work equally well with any index of refraction. Fig. 6 is given to illustrate the necessity for figuring new indexes when there are several mediums, or when air is not one of the mediums used. The Single Perpendicular method is employed to illustrate its simplicity. First the comparison of indexes is made and recorded : Air is to water as 3 is to 4 ; water is to glass as 8 is to 9 ; glass is to diamond as 3 is to 5 ; diamond is to air as 2 is to 1. R 1 , R 2 , R 3 , R 4 , R 5 , are the several sections of the ray. The distance from 1, on the perpendicular to 2, where the incident section crosses, multiplied by the index of water, 1.33^, gives the distance from 1 to 3, from which point the refracted section takes its course in the water; the distance from 3 to 4, multiplied by the index of glass compared with water (9 is to 8 as 1.125 is to 1.00), gives the "distance from 4 to 5, from which point the refracted section takes its course in the glass; the distance from 5 to 6, multiplied by the index of diamond com- pared with glass (5 is to 3 as 1.66$ is to 1.00), gives the distance from 6 to 7, from which point the refracted section in the diamond takes its course; the distance from 7 to 8, divided by the index of diamond, 2.50, gives the distance from 8 to 9, from which point the emergent section takes its course. The principles exhibited by plane, parallel surface refraction hold good all the way through the work ; but, as we proceed, we shall find new ones added, which, at a glance, may appear to supersede these. This is not true, however, as will be shown. /// i IA/iXw ! M '} ' $ 4f $ /. 33^-^6 //v 9 1 /'if *''* 20 A SYSTEM OF MATURE MEDICINE Physical principles extend far beyond purely physical matters. They work physiologically and metaphysically. They are the base of true theory and practice. In this chapter we have been introduced to Infinity and discover at once that It is something greater than any possible conception of a personal "creator" or "ruler," such as has been pictured in alleged "holy" books writ- ten by professedly "inspired" people of a mythical age. Note the law of constants and inconstants as exemplified in the constancy of the density of Natural mediums and the inconstancy of artificial ones ; also in the changeable angles of incidence and the constancy of their relations to other angles. The limit angle teaches there is not only a limit to the effectiveness of all laws,,, but a limit to our capacities of comprehension, endurance, etc. As the limit angles are different for different mediums, so are the capacities of different people unlike. As refraction is accompanied by reflection, dispersion and absorption, so is learning associated with losses, distortions and misunderstandings; hence we must have means of proving conclusions. In the illustrations we have the dualities : two indexes, two perpen- diculars, two parallels, two. base-lines, two refracting surfaces, etc. Then there are double dualities : the four sections of a ray, the four angles with the perpendiculars, the four effects, reflection, refraction, dispersion, absorp- tion. We originated and are the sole teachers of the method of straightening cross-eyes without operation, thus avoiding the possibilities of death from cocaine poisoning. We prove operation is not needed, hence is a dangerous proposition in many ways. CHAPTER H. Refraction and Reflection by Plane Surfaces, Forming Prisms. As a physical proposition prisms present many important features. As a physiological one it is most important to know why they should not be employed therapeutically. The latter phase of this subject will be attended to in detail in another chapter. The laws employed in illustrating refraction and reflection by plane, parallel surfaces apply equally well to plane surfaces inclined toward each other, forming prisms ; but the final result, exhibited by the emergent ray, is different, because of the change in shape of the denser medium. The sur- faces not being parallel the perpendiculars cannot be, hence the course of an emergent section is not parallel with that of the incident section, but is always toward the base line of the prism. Fig. 7 shows a prism, or transparent wedge. Other illustrations will show the angle of construction, or the angle formed by the two sides and the base, as may be seen in the two ends of this figure. They will also show the angle of deviation, which is the amount of change in the course of a ray passing a prism. Also other features of prisms will be shown, all of which are of great importance to the student. To be convinced quickly of the deceptive quali- ties of prisms the student needs only to look at the drawing steadily, holding a finger at the upper left corner, when he will note the prism apparently re- **/' verses ends so that the finger will be seen first on one side of the figure, then on the other. Next, lay the book on a table, sit at arm's length and rotate it, keeping the eyes fixed obliquely downward on the prism and watch its antics. These optical illusions are the complementary exhibits associated with all vision, which will be considered further in the physiological portion of this work. Fig. 8 illustrates several points: First, that portion showing above the base line, B L, is the prism, its angle of construction shown by the two sides and the base line connecting them ; second, the apex is the center of the part of a circle which cuts the base line to include the base of the prism as the chord of the circle, the arc showing just below; third, the portion of the drawing below the base line forms an air angle, which, measured on 22 A SYSTEM OF MATURE MEDICINE the vertical midline, is to the whole line as the index of air is to that of the dense medium, 1.00 to 1.50 in this instance. This gives at y the length of the base of the angle of deviation by the first surface, and at x the base of the angle of deviation by the prism. The drawing is made by the Perpendicular Parallel method, R' being the incident section of a ray, which is broken at the first surface toward the point F' on line PI' as if it came from R 2 ; and at the second surface it is broken toward F 2 , on the base line, as if it came from R 3 , which, with R' forms the angle of deviation, D, measured at a point as far from the meet- ing point of those two rays, O, as the prism is high on its mid-line. D corresponds to X on the air angle, or to the base of the prism, (the arc, strictly) multiplied by the excess index of the dense medium, .50. The line 4 P' is the perpendicular to allel ; P 2 is the perpendicular parallel. The measurements manner as in Fig. 1. The with the base line and one troduce the system of mon use. The unit is a angle that a ray entering and one centimeter from it 100 centimeters (1 meter) dis- base line 8 cm. from the dot of refraction, hence, 8 divided If the incident ray is at a great- than 1 cm. the units found by by the distance the incident ray of value. Thus, if the incident timeter from the base line and after refraction, it would be and one-half centimeters from point on the base line after re- times as strong. The angle of reflection at the same as the angle of in- the first surface and PI' is its par- to the second surface and PI 2 is its of the angles are made in the same incident ray approaches parallel centimeter from it. This is to in- numbering prisms which is in corn- prism of such a deviating f*?' parallel with the base line will be broken to meet the base line tant. This figure breaks the ray to the , on the base line marking the plane into 100, gives 12.5 units of power. er or less distance from the base line the above process must be multiplied is from the base line to get the units ray in this figure was only half a cen- had the same point on the base line only half as strong; but if it was one the base line and still had the same fraction, it would be one and one-half each surface of the prism would be cidence to each surface, and on the REFRACTION BY PRISMS 23 opposite side of the perpendiculars. They are not shown in the drawing because they ought to be understood on account of their constancy. -/Pi Fig. 9 shows the base line of the 'allel with it; other this instance a line face to the point C' long, and, with index Base-Line method as applied to prisms. The prism is utilized when the incident ray is par- wise special base lines must be supplied. In (dashed) from where R' strikes the first sur- would correspond to x' Fig. 4. It is 50 mm. 1.50: 50X1-50 = 75-=- .50 = 150 mm. from the plane of refraction to F' on the Base-Line 1 , would be the direction of the 'refracted section of the ray, as^ if it came from R 2 toward F'. Base-Line 2 is drawn parallel with the refracted section and the distance (dashed) from C 2 on that line to the point where the second break occurs, corresponds to x 2 Fig. 4, hence, 38-h- .50 = 76 mm. from the dot on the base-line below the prism to the point F 2 , toward which the emergent section will be directed. As in Fig. 8, x, on the form below, equals D the base of the angle of deviation. The angle of construction of a prism and the angle of deviation formed by it are in the same ratio that air bears to the excess index of the denser medium, hence the rule : To find the angle of construction for any required angle of deviation. Divide the angle of deviation by the excess index of the dense medium. Or, if the angle of construction is known, in degrees, minutes and seconds, or any base line measure, to find the angle of deviation, multiply by the excess index of the dense medium. This rule is exact so long as the prism is weak enough so that if a cir- cle be drawn with the prism apex for its center, its sides the radii and its base the chord, the arc can scarcely be distinguished from the chord. See Fig. 8. In Figs. 8 and 9 the portions below the base lines of the prisms are to the entire figure as 1.00 is to 1.50 and it will be noted that the apexes of the angles of deviation are at points distance from the first surfaces toward the second in exactly the same ratio, or two-thirds of the thickness of the prisms on the line of incidence. Were the index 1.52 the apexes of the angles of deviation would be 10< /]-,:> of the distance across the prisms on the lines of incidence. The total length of the lines bisecting Figs. 8 and 9 represent in units A SYSTEM OF MATURE MEDICINE the indexes of refraction of the dense mediums. The portions above the base lines represent the excess index of the dense mediums over the rare. The portions below the base lines represent the standard index of air, 1.00. In these instances, the index being 1.50, the lines are 150 points long and the base lines cut them 50 points from the tops, leaving 100 below ; had the index been 1.52 there would be 52 points above to 100 below. Then the lines at the lower ends of the figures, measured at x, a distance from the lower points equal to the height of the prisms, are always the measures of the angles of deviation, their apexes being at points in the prisms, found in the manner described in the preceding paragraph. Fig. 10 shows a prism 6 mm. thick on the line of incidence, 1 1, same as in Fig. 9. As the index is 1.00 outside and 1.50 inside, the location of the apex of the angle of deviation will be 4 mm. from the first surface, be- cause 4 is to 6 as 1.00 is to 1.50. Measuring from that point backward on the line of incidence a distance equal to the height of the prism we erect the vertical line A which is the base of the angle of deviation because the base- line of the prism, 10 mm., multiplied by the excess index, .50, gives 5, the length of the line at A. Or, we get the same thing from the line x in Fig. 9. Then, running the line 3 3, from the line A through the point located in the prism, we have the emergent course to F. All we have to do to show the refracted section is to draw a line connecting the incident and emergent sections, as shown by the line 2 2 as it passes from surface to surface of the prism. I have added here the line P, which is perpendicular to the first surface and measures 52 mm. Applying the rule, we have : , 52x1.50 = 78-^- .50 = 156 mm. as the distance on the base line, measured from the plane of refraction along the line 2 2 to a point toward which the refracted ray will be directed while passing the prism. Then at the second surface I have another Base-Line and a perpendicular, P 2 , which measures 19 mm., which divided by .50, gives 38 mm. to the point x on Base-Line'-' measured from the dot on that line in the prism. This gives the final course of the ray to F and enables us to prove the other method worked correctly. The position of the dot is found as in Fig. 4. It is a coincidence worthy of mention that rays approaching parallel with the base line of a prism of two equal sides and an index of 1.50 will emerge parallel with the perpendicular to the point of contact with the first surface. Rays approaching a prism parallel will all strike it at like angles and will be refracted the same, passing away parallel ; but if they approach at different angles the effects will be different. REFRACTION BY PRISMS Fig. 11 shows rays starting from O as 1, 2, 3, and the same lines after refraction by the prism ; 1 and 2 pass away as if they came from the point A, while 2 and 3 appear to come from point B. The amount of refraction is the same for each ray, as is shown by the dotted lines marking the angles of deviation, but the effects are different as is exhibited in the points A and B. This we will call angle aberration or maximum, intermediate and minimum refraction. Any ray from O, striking the surface above the line 2 will be refracted so that it will meet line 2 in the general direction B, a little farther away than a plane erected at O ; and any ray striking tlje prism below line 2 will be refracted so that it will meet line 2 in the general direction A, a little nearer than a plane at O. Thus it can be seen that minimum re- fraction occurs in any given instance on the ray that passes the prism exactly parallel with the base line, as 2 in this instance, and maximum re- fraction occurs on rays which pass above or below that ray, which we will call the dominant ray. In Chapter I reference was made to the dispersion of light into its elementary colors. This applies particularly to Natural light, which is sunlight, and that developed artificially, as the calcium light and the electric arc light which approach very nearly the composition of sunlight. In the early days of modern optical study, something over a hundred years ago, when microscopy was in its infancy, it was found, when lenses were made of such curves that they magnified objects as much as twenty diameters, 400 times, the virtual object, as seen through the lens, was indistinct and somewhat colored. It was soon found that the chemical composition of the lens had some part in this disturbance and that the curves of the surface did the rest. These were denominated chromatic aberration, because of the colors, and spherical aberration, because of the forms of the lenses. The latter will be explained elsewhere in this book. Experiments developed the fact that differences in the composition of the glass used caused great variations in the amount of dispersion, but com- paratively little in the refracting properties. Fig. 12 shows dispersion by a prism of "crown" glass, the seven parallel incident lines representing a ray of white light and their continuations through the prism show the different re- fractive effects on the several ele- mentary colors which result in the development of the spec- trum, comprising red, orange, A SYSTEM OF MATURE MEDICINE yellow, green, 'blue, indigo, violet. Another prism, made from "flint" glass, having practically the same index of refraction, would have nearly twice as much dispersive power; hence a "flint" prism with an angle of construction half as great as the "crown," Fig. 12, would have as much dispersive power, thus proving that it is the chemical attraction of glass which dominates in the duality regulating the amount of refraction, instead of what is ordinarily expressed as "the angle of incidence and the optical density of the dense medium." Fig. 13 shows how the two prisms may be combined to eliminate dispersion, yet secure any amount of refraction desired : Simply combine two prisms, one of "crown" and the other of "flint" glass, the latter constructed one-half as large as the other, when the double dispersive power of the "flint" will neutralize the dispersion of the "crown," while the refraction of the "crown," being twice that of the "flint," on account of its angle of construc- tion, will still render half of its original power. Application of the principle to lenses will be explained in the chapters on that subject. They will be understood better there. Fig. 14, | cm. scale, shows two combinations of prisms having, respect- ively, positive (-)-) and negative ( ) effects on rays passed through them. The two combinations are made in one drawing to show how the figures for one may be used for the other. The base line of the -+- is the apex line of the other, except that in the -- the apexes lap each other; if made absolutely REFRACTION BY PRISMS apex to apex there would be nothing at the mid-line. This will show why - lenses are a little heavier than -j- of the same power. What has been called the base line. of prisms will hereafter be called the axial line, because there will always be something on both sides of it. The ray R, connecting the two combinations, parallels the axis and the line P, perpendicular to the first surface of the -j- prism, will be used to find the courses of the rays through both combinations. After finding the course of the refracted ray in the -f- prism by the Perpendicular Parallel method, shown by the line 2 2, the line 3 3, drawn parallel with it, through the combination, gives the course of the refracted ray in that instance. Then, drawing the emergent ray, R', 'from the second surface of the -f- prism, parallel with the perpen- dicular to the first surface, to the point F', and drawing the emergent ray, R 2 , from the - - prism, parallel with R' as if it came from the point F 2 . we have the figure complete, showing a positive focus at F' by the -J- com- bination, and a negative focus at F 2 by the combination. Fig. 15 illustrates further the effect of prisms with bases together and reversed. Parallel rays, marked x, which approach at equal distances from the axial line, are refracted toward points by the -f- combination, while from the combination they pass away after refraction as if they came from the points indicated by the dashed lines. On the left we have the positive focal points of the -f- and on the right of them are the negative focal points of the - combinations, and we have the reasons for each. (Fig. 15 is not made to measure.) Fig. 16 shows, at the left, a curved surface at a little distance from the prism surfaces. The meeting point, C', of the perpendiculars, P', to the surfaces of the prisms, is used as the center of curvature of the curved sur- face to illustrate that at the points where the lines pass the curve they are perpendicular to both surface*, and at no other points would a perpendicular A SYSTEM OF MATURE MEDICINE to either surface be perpendicular to the other; hence, those points are the only ones where those prisms are represented in the curved line. On the right the curved surface is drawn so the prism surfaces are -tangents, to show that pafallel rays, striking the points where the perpendiculars P 2 are erected, would, with an index of 1.50, be refracted to the point indicated by the dashed lines, because the distance from the points of refraction to C 2 (51 mm.) multiplied by 1.50 and divided by .50 gives 63 mm. As the rest of the prism surface is cut away and other angles, really multitudes of prisms, substituted automatically in grinding the curved surface, the result is a common focus of all the parallel rays at that point, with an exception which will be explained in the next chapter. This woman's eyes were straightened instantly by our operationless methods. CHAPTER III. Refraction and Reflection By Single Curved Surfaces. All principles of laws are constant; but the manner in which they are employed may seem to modify them; and, to some extent, this is actually true. It is all the more necessary to study them closely. As was shown at the end of Chapter II, curved surfaces are equivalent to a multitude of prisms. To erect perpendiculars to plane surfaces a square must be used; and even then it is difficult to be exact; but all spherical curves have centers from which all radial lines are perpendiculars to the prisms forming- the surfaces pierced by them. The propositions offered by single curved surfaces are: 1. Rays approaching them parallel with the course of any radial line, or divergent from any such line and starting from a point farther from the surface than the principal focal distance of the curved surface presented, will be brought to a focus by refraction, if the curve be positive, and by reflection if the curve be negative. There will also be a negative focus, by reflection, in the first instance, and by refraction in the second. 2. The center of curvature establishes a starting point for all perpen- diculars to the surface. It is the optical center and nodal points, because all rays directed toward it pass the surface perpendicularly, hence without re- fraction. 3. The radius of curvature and the index of refraction constitute the basis on which the refracting power is figured. 4. Single curved surfaces have first and second principal focal distances by refraction; the second being in the same ratio to the first that the index of refraction of the dense medium bears to that of the rare. With reference to the index, the radius, and the principal focal distances we have the fol- lowing : 1. The radius, divided by the excess index of the dense medium gives the first principal focal distance, in the rare medium. Formula: R-=-ExI=F' 2. The radius, multiplied by the index of the dense medium and divided by the excess index, gives the second principal focal distance, in the dense medium. Formula: R x I -f- ExI = F 2 3. Adding the radius to the first principal focal distance gives the sec- ond principal focal distance; or, subtracting the radius from the second will give the first. Formula: F' + R = F 2 . Or, F 2 R = F' A SYSTEM OF MATURE MEDICINE 4. The radius, divided by the first principal focal distance, gives the excess index of the denser medium. Formula: R -f- F' = ExI. 5. The first principal focal distance, multiplied by the excess index, gives the radius. Formula: F' x ExI =z R. 6. The second principal focal distance, divided by the first principal focal distance, gives the index. Formula: F 2 -j- F' = I. 7. The first principal focal distance, multiplied by the index, gives the second principal focal distance. Formula: F' x I = F*. Or, the second principal focal distance, divided by the index, gives the first principal focal distance. Formula: F 2 -r- 1 F'. 8. The second principal focal distance, multiplied by the excess index and divided by the index, gives the radius of curvature. Formula : F 2 x ExI -=- I = R. With reference to conjugate focal distances, that is, points where objects and their images are located outside of the principal focal distances, we have : 1. Any distance farther from the surface than the principal focal dis- tance, on either side, multiplied by the principal focal distance on the op- posite side and divided by the difference between itself and the principal focal distance on the near side, will give the conjugate focal distance on the opposite side. Formula : Cf x OPf + (Cf ' NPf ) = Cf 2 . Or, the two principal focal distances multiplied together and divided by the difference between the given conjugate focal distance and the principal focal distance on the near side, will give an amount which, added to the principal focal distance on the opposite side, will be the second conjugate focal distance. Formula: (F' x F 2 ) * (Cf NRf) + OPf = Cf 2 . 2. The first conjugate focal distance, multiplied by the index and by the radius, and the product divided by a figure obtained by multiplying the first conjugate focal distance by the excess index and subtracting the radius, will give the second conjugate focal distance. (Cf'xI)xR Formula: , ^,, ,, =- = Cf . (Cf x ExI) R 3. The second conjugate focal distance, multiplied by the radius and the product divided by a figure obtained by multiplying the second conjugate focal distance by the excess index and subtracting another figure secured by multiplying the index by the radius, will give the first conjugate focal distance. - CPxR formula: t -^ =- = Cf . (Grx ExI) (I x R) 4. The first and second conjugate focal distances multiplied together, the product multiplied by the excess index, and the result divided by a figure obtained by multiplying the first conjugate focal distance by the index and adding the second conjugate focal distance, will give the radius. ^ (Cf x Cf 2 ) x ExI Formula: (CfxI)+Cf = R REFRACTION BY SINGLE CV:RVED SURFACES 31 5. Express both conjugate focal distances in diopters ; multiply the second by the index; add the first, to get the total power; convert to prin- cipal focal distance and multiply by the excess index to get the radius. Formula: (Cf 2 D x T) -(- Cf'D Total dioptric power. (100 -f- D power)= F' x ExI = R. The reason for multiplying the second conjugate focal power by the index is that in calculating in diopters the comparative weakness of the focusing power in the dense medium must be allowed for. 6. Having both conjugate focal distances and the radius of curvature, to find the index of refraction, the first conjugate focal distance, plus the radius, multiplied by the second conjugate focal distance will give a figure to be divided by another, found by subtracting the radius from the second conjugate focal distance and multiplying the product by the first conjugate focal distance. _ (Cf + R)xCf 2 Formula: _______= i. 7. Having the principal focal distances and the. first conjugate focal distance, in the rare medium, to calculate the second conjugate focal distance by the dioptric method: First express the given distances in diopters and take the difference between fliem ; second, as the power of the curve on rays entering the denser medium is to that on leaving it as the index of the rare medium is to that of the dense, divide the remaining dioptric power by the index of the denser medium to get the actual effect on entering it; the product, transposed to focal distance, will locate the second conjugate focal point. Formula: (F'D Cf'D) = Cf'D -4- 1 (transposed) = Cf 2 . If the first conjugate focal point is in the denser medium, the first conjugate focal distance, expressed in diopters, must be multiplied by the index of refraction of the denser medium, because the power is increased on leaving it ; then the product is deducted from the principal focal power expressed in diopters, and the remainder, converted to focal distance, will be the second conjugate focal distance. In other words, reversing the calcula- tion made above we have the second conjugate focal distance, in the dense medium, and want to find the first. Formula: F'D (Cf 2 D x I) = Cf'D. 8. The principal focus, by refraction, is an inconstant, being regulated by the index of refraction and the radius of curvature. The principal focus by reflection, is a constant, being always at one half of the radial distance of the surface presented, no matter what the index of the medium is, or whether it be glass or other polished substance. Rays form principal focuses only when they approach a curved surface parallel with the course of a radial line passing from the center of curvature through the apex of that curvature. It is known as the axial line. In Fig. 17, millimeter scale, we have a radius of 20 millimeters. To locate, by calculation, the first principal focal point, to which the ray R' will be directed, we have the law : Radius, divided by excess index gives first principal focal distance ; thus : 20-=- .50 = 40, the first principal focal distance. The points are also found by the perpendicular-parallel method and the an- gles are marked 1 and H. R', parallel with the axial line, in the dense A SYSTEM OF MATURE MEDICINE medium, forms angle 1 with the perpendicular P' in the dense medium, and refraction causes the angle 1, with the same perpendicular, in the rare medium, the refracted section going to F'. Note the dashed line, O', to the point x; it is positive reflection of a portion of R'. To locate, by calculation, the second principal focal point, to which ray R 2 will be directed, we have the law : Radius, multiplied by index and divided by excess index, gives second principal focal distance ; thus, (20xl.50)-H .50 = 60. the second principal focal distance. By the perpendicular-parallel method R 2 , parallel with the axial line in the rare medium, forms angle H with the perpendicular, P 2 , in the rare medium, and refraction causes the angle 1, with the same perpendicular, in the dense medium, the refracted section going to F 2 . Note the dashed line, O 2 , from the surface ; it is the negative reflection of a portion of R 2 and leaves the surface as if it came from x where the reflected portion of R' actually went. The reason for the two principal focal distances will be understood readily when it is observed that the angle formed by R', as it approaches the surface in the dense medium, is increased fifty per cent, as it leaves that medium ; while the angle formed by R 2 , as it approaches the surface in the rare medium, is reduced only one-third as it enters the dense medium. The relation be- tween these two focal distances is always in the same ratio as are the in- dexes of the two mediums. As we have measured from the refracting sur- face the long focal distance is shown in the dense medium. If we had measured from the optical center, C, the short focus would be in the dense medium. When we come to lenses the measurements will be from the surface in some instances, from the optical center and from nodal points in others. I l.ffO Fig. 18 shows how parallel rays, R R, entering the denser medium, are brought to a common point at the second principal focal distance of the curvature, which has a radius of 30 millimeters hence, REFRACTION BY SINGLE CURVED SURFACES (30xl.50)-f- .50 = 90, the second principal focal distance. If the rays were parallel in the denser medium they would be focused outside at 60 millimeters, because, 30-^ .50 = 60, the first principal focal distance. The point on the axial line where the curved surface crosses it is the principal point and a vertical line, at right angles with the axial line at this point is the principal plane of a surface. Fig. 19 shows how parallel rays, R R, in the denser medium, pass away after refraction as if they came from F. With the same radius as Fig. 18 the short focus is now found inside, measuring from the surface ; this is be- cause of the law, as explained by Fig. 17, that the greatest effects are upon rays leaving the dense medium. If the rays were parallel in the rare medium they would be refracted on entering the dense and pass away from the sur- face as if they came from a point 90 mm. from the surface. This is negative refraction, based on the comparative breaks toward and from the axis. In the first sentence of this and at the close of the preceding chapter, reference was made to modifications of the law r s. We have an instance of that here : Figs. 18 and 19 are not absolutely true. The law, as given for refraction by plane surfaces, is as sure as ever for single rays ; but, it will be remembered, a limit angle was mentioned, where all laws cease to apply, and the point where total reflection occurs was cited as an example. In Fig. 20, millimeter scale, we have another exhibit. Students will re- call the injunction that the amount of refraction is regulated by the density (chemical attraction) of the medium and the angle of incidence. The density is constant in a given medium, but the angles of incidence differ; hence, while A SYSTEM OF MATURE MEDICINE the angles of incidence and of refraction bear the same relation to each other, with reference to R' and R 3 , being 1^ to 1 each, the rays R' and R 2 focus at F', while those from R 3 and R' 1 focus at F 2 . So rays between R' and R 4 and between R 2 and R 3 would focus at different distances between F' and F 2 , and rays nearer the axis than R' and R 2 would focus beyond F'. Thus we discover that spherical aberration prevents the possibility of any such perfect focus as shown by Figs. 18 and 19. Concave lenses have the same faults, negatively, as Fig. 19 is the reverse of Fig. 18. Inasmuch as the central spaces of curved surfaces are utilized chiefly, and as the law of calculation fits the point F',~ supported by lenses, under practical tests, by giving the best pictures at such points, we have a pretty illustration of how Nature supplies theoretical means of learning the best practical applications of laws. Fig. 20 has a radius of 30 millimeters; the index is 1.50; hence: 30x1.50 = 45-f- .50 = 90, the second principal focal distance, F'. This is corroborated by the perpendicular-parallel method on the ray R'. But the same method applied to R 3 shows F 2 at 76 millimeters, because the angles at which rays R 3 and R 4 strike the surface are much greater than the others. The effect of the aberration, as shown, is to make all spherically curved surfaces astigmatic, that is without a common focal point, because the rays which cross the axis at many points from F 2 to F' and beyond, pass away divergent and form circles of diffusion or spots of light instead of focuses. It should be borne in mind that the drawing only shows a sectional view and that the entire front of a spherical surface would give many rays from every point around the axis, so that the lines in the drawing, before and after crossing the axis, represent the diameters of circles which combine to produce what has been termed a caustic. This is most pronounced in curves of long radius, because, when the radius is very short, the distance between F 2 and F' is so short as to be scarcely noticeable, except in high power instruments. When a lens has such curves that it focuses at about two inches the caustic is so small that the focus is nearly enough perfect that it may be used for a burning-lens. Principal focuses are fixed, or constant; always the same for any given index and curve ; because they are always products of rays which were parallel before refraction. Conjugate focuses are inconstant, or shifty. Fig. 21, millimeter scale shows the first and second principal focuses of a -}- curved surface, as found by calculation according to the rules given, namely ; the radius divided by the excess index of the dense medium gives the first principal focal distance and adding the radius gives the second principal REFRACTION BY SINGLE CURVED SURFACES 35 local distance. The negative focus of the reflected portion of R 2 , shown as the line x, is indicated by the point NF. Fig. 22, millimeter scale, shows the principal focal distance, by reflection, and the two principal focal distances, by refraction, of a surface. The ray R 2 is reflected to the point PF, one-half the radial distance from the sur- face. This is the positive focal distance. The same ray is refracted and goes toward x 2 as if it came from F 2 . This is a negative focal distance. The ray R' is refracted toward x' as if it came from F'. This is also a negative focal distance. Note that the reflected portion of R' goes away as if it came from PF, making that point the negative focus of that portion by reflection while it is the positive focus of R 2 by reflection. Also note that the long focal distance is on the outside and the short one on the inside of the dense medium; just the reverse of Fig. 21. Rays approaching divergent from the axis and from a point farther away than the principal focal distance, will be rendered convergent by refraction through a -|- surface and will meet the axis at a point which can always be located by calculation according to the rule: The given conjugate focal distance, multiplied by the opposite principal focal distance, and divided by the difference between the given conjugate focal distance and the principal focal distance on the near side, will give the other conjugate focal distance. Conjugate means, literally, "yoked together" ; hence, points which send rays to and receive them from each other, by refraction or reflection, are in conjugate focus. In Fig. 23, mm. scale, CF' is 40 points distant from the surface ; F 2 is 30 points from the surface ; the difference between CF' and F' is 20 points ; therefore, applying the rule : 40x30 = 1200-1-20 = 60, the second conjugate focal distance, CF 2 . To prove it work it backwards. CF 2 is 60 points ; F' is 20 points ; the difference between CF 2 and F 2 is 30 points, hence : 60x20 = 1200-f-30 = 40, the opposite conjugate focal distance, CF'. To calculate the second conjugate focal distance by the dioptric method, the first principal focal distance being 20 cm., or 5.00 diopters and the first conjugate focal distance being 40 cm., or 2.50 diopters, we deduct it from the 5.00, leaving 2.50 ; then, as the power of the curve on entering the denser medium is to that on leaving it as the index of air is to that of the denser A SYSTEM OF MATURE MEDICINE medium, we divide the 2.50 by the index 1.50 which gives the dioptric power on entering as 1.66f or a second conjugate focal distance of GO cm. Going the other way, 60 is the first conjugate focal distance, or 1.66 diopters, which must be multiplied by 1.50, the index, because the power increases outside ; this multiplication gives 2.50 ; the outside principal focus being 20 cm., or 5.00 diopters we deduct our 2.50 from it leaving 2.50 or the 40 cm. outside conjugate focal distance. These points being established, we know that rays from one of them will diverge from the axis until the curved surface starts convergence, when they will meet at the other, no matter where they strike the surface. This is ignoring the aberration feature, because it is not sufficient to spoil the image formed, as will be shown. Another way to locate the opposite conjugate focal point is shown in Fig. 24, mm. scale. Let CF' be the first conjugate focal point and F' be the first principal focal point, with PI as its plane. Draw the line R of D (ray of direction) to any point on the curve ; then start the guide line from the point on the line PI where the line R of D crosses, and extend it through the center of curvature at C ; then continue the ray parallel with the guide line until it strikes the axis. This works no matter what the index of re- fraction may be, because the change in the location of the principal focus to suit the index of refraction takes care of such differences. Fig. 25, mm. scale, shows a curve with a radius of 20 points ; index, 1.50; negative principal focal distances, (50 and 40; first conjugate focal dis- tance, CF', at 80 points. To find the second conjugate focal distance by reflection from the concave surface : Multiply the first conjugate focal dis- tance by the principal focal distance and divide by the difference between them. The principal focal distance is one-half of the radius, or 10 points; Hence: 80x10 = 800-;-70 = 11.43, the second conjugate focal distance. To find the direction of the refracted portion x 2 : Express the first conjugate focal distance and the negative focal distance on the same side of the surface in units based on a standard of 1,000 millimeters to the unit ; add them and divide the product into 1,000 to convert back into distance. Thus, with a radius of 20 and an index of 1.50 the outside negative focal distance is 60; the first conjugate focal distance is given as 80; each of these, divided into 1,000, gives 16.66% units for the 60 and 12.50 units for the 80; the 12.50, REFRACTION BY SINGLE CURVED SURFACES divided by the index, 1.50, on account of deficient unit power in single curves, leaves 8.33%, which, added to 16.66%, gives 25.00 units, which, divided into 1,000, gives 40 mm. from the surface to the point x', from which the ray x 2 appears to proceed. 4 Or use: Formula: (CF'xNPF)-f-(Cf'+OPF) = x'. The negative principal focal distance on the outside is 60 ; the con- jugate focal distance on that side is 80, therefore: 80x60 = 4800-f- (80+ 40) 120 = 40, or x'. c' Fig. 26, mm. scale, shows the manner in which real images are formed, inverted. The object at the left is 48 millimeters from the principal point, (apex of curvature) of a curve with a radius of 12, index 1.50, hence a first principal focal distance of 24 and a second principal focal distance of 36 millimeters. The difference between the object distance and the first principal focal distance is 24 ; hence : 48x36 = 1728-4-24 = 72, the position of the image at the right. The rays from B' focus at B 2 , according to the law as illustrated in Figs. 22 and 23. For the same reason rays from A' focus at A 2 and those from C' focus at C 2 , because the lines 2 and 8 are secondary axial rays crossing the principal axis at the optical center, while other rays, from points between A' and C', would focus at corresponding points between A 2 and C 2 , forming a complete real image, inverted, as it would appear on a screen if tested practically, as can be done with lenses. Note that the object is at twice the first principal focal distance; that the relation between the two conjugate focal distances from the surface is the same as that between the two indexes; that the distances of object and image from the optical center are equal; that object and image are of equal size. Fig. 27, mm. scale, shows how virtual objects are formed, erect, by concave surfaces. O' is the real object, 80 mm. from the surface, which has a radius of 20 mm., a long negative focus of 60 mm. in air and a short one of 40 mm. in the glass. The divergent rays. 2-2 from the axis at the real object, 80 mm., represent a negative power of 12.50 units, divided by 1.50 on 38 A SYSTEM OF MATURE MEDICINE account of the unit deficiency of the single curved surface, leaves 8. 331/3 units to be added to the 16.66%, represented by the negative focal distance of 60 mm., making a total of 25.00 units, with a negative focal point of 40 mm., which is at the plane O 2 . The rays 3-3 and 4-4 are refracted and pass away as if they came from the points on the real object from which they actually proceed. The rays 1-1 pass through the center of curvature, C, hence the course is straight back. This explains why objects seen through concave lenses always appear nearer and reduced in size. The sizes of image and object are as the distances from C to each ; in this instance, as 20 is to 60. Some writers have compared this with Fig. 26 to show that "convex lenses form real images, inverted, and concave lenses form virtual images, erect." This is a false statement. First, there is no such a thing as a virtual image; second, convex lenses form real images, inverted, by refraction, and concave lenses form the same things, by reflection. Both are positive in this respect. Both form virtual objects, negatively, by refraction, that is where the objects appear to be when viewed through the lenses. Fig. 28, mm. scale, shows how virtual objects, erect, are formed, nega- tively, by convex surfaces. The real object, at O sends rays (the black lines) to F 2 along lines 1, 1, 1, 1 and to 2, 2 in the dense medium as if they came from O ; also the clashed lines from top and bottom to C. Extending all of these lines backward (dashed) from the surface, they appear to come from the points T O 2 B, the virtual object. This explains why objects seen through convex lenses appear more distant and larger than they really are. In this connection it is worthy of note that while, as a rule, convex surfaces are positive and concave ones are negative in matters of refraction and the reverse in matters of reflection, there are times when, figuring on negative propositions, the concave is radically positive. For example, the rule for figuring the position of the virtual object for any concave lens is : Multiply the first conjugate focal distance, by the principal focal distance, (negative), and divide the product by the sum of the first conjugate focal distance and the principal (negative) focal distance. The same rule applies to single curved concave surfaces. In Fig. 27 the first conjugate focal dis- tance is 80 mm., the principal focal distance (negative) is 60. Multiplying them together and dividing as per formula, page 37, locates the virtual object 40 mm. from surface. The virtual objects seen through convex sur- faces and lenses are as radically negative. Fig. 28 shows a convex surface with a radius of 20 mm., a first principal focal distance of 40 mm., a second principal focal distance of 60 mm., and a real object 20 mm. from the surface. To find the location of the virtual object: Multiply the first conjugate focal REFLECTION BY MIRRORS distance by the second principal focal distance and divide by the difference between the first principal focal distance and the object distance. Thus 20x60 = 1200-K40 20) 20 = 60, the position of the virtual object. Or, the first principal focal distance, expressed in units, (diopters), and the object distance expressed in the same form, the first subtracted from the second, the product converted to millimeters and the result multiplied by the index, will give the same result. Thus, the first principal focal distance, 40, is 25.00 units; the object distance 20, is 50.00 units: the difference is 25.00 units, or 40 mm. ; this, multiplied by the index, 1.50, gives 60 as the virtual object distance. The reason for this proceeding is that the real object position, 20 mm., is calling for 50.00 units of power to render entering rays parallel if they were to pass through a lens; it is only receiving half of that amount, hence there is a deficit of 25.00 units ; and, as it is a single curved surface, only two-thirds of that amount is really represented, or 16.66% units, ren- dering a negative focus of 60 mm. Fig. 29, mm. scale, illustrates the formation of real images, inverted, by reflection, from any concave polished surface. Let A represent a concave mirror with a radius of 40 mm. with the object "O" at 100 mm. The principal focal point, being midway between the surface and the center of curvature, is 20 mm. ; hence : 100x20 = 2,000^- (10020) 80 = 25, the second conjugate focal distance, or the position of the image, I. The manner in which it is formed is that the rays on lines x' and x 2 are reflected straight back upon their courses and meet rays represented by lines 1 and 2 respect- ively on the same plane, at 25, while other rays from points on the object between top and bottom form the rest of the image. The angles of re- flection are not quite equal to the angles of incidence in this instance because the point at which reflection occurs is at such a distance from- the axis that spherical aberration is exhibited. The drawing was made by calculation. Concave spherical mirrors have a magnifying, erect effect when looked into from a point inside the principal focal distance, and an inverted, minify- ing effect when looked into from a point outside the center of curvature. Convex spherical mirrors have a minifying, erect effect when looked into from any distance. Cylindrical mirrors, concave or convex have similar effects to the spherical on the meridians of curvature only. Plane mirrors reflect without magnifying or minifying. Fig. 30 shows why concave mirrors have a magnifying effect when the object is inside of the principal focal distance: The- rays 1 from the top and bottom of the object O strike the surface of the mirror as if they came from the center of curvature C and are reflected back along the same lines because 40 A SYSTEM OF MATURE MEDICINE they are perpendicular to the surface; rays 2 from top and bottom of object approach the surface of the mirror parallel with the axial line, hence are reflected toward the principal focal point F as if they came from T and B at which points they meet the continuation of lines 1; therefore I is the magnified image of O. If the object be placed outside of the principal focal distance an inverted image will be formed, minified if object is outside of the center of curvature and magnified if object is between the center of curvature and the principal focal point on the same side of the mirror. Fig. 31 shows why convex mirrors minify. The rays 1 from top and bottom of object are directed toward C, the center of curvature, and the rays 2, from the same points, are directed toward F, the negative focal point of the mirror, hence are reflected as if they came from T and B where they meet the rays 1. It is easy to see that the farther the object is from the surface the smaller the reflected image. CHAPTER IV. Refraction and Reflection by Piano-Convex Lenses. Fig. 3.2, $ mm. scale, shows the principal focal points, optical center and nodal points of a plano-convex lens. Rays R 2 , entering from the plane side, parallel with the axis, only suffer refraction at the curved surface, hence the rule for finding the prin- cipal focal distance of single curved surfaces applies without change : Radius, divided by excess index, equals principal focus, F 3 . R', entering the curved surface are refracted as in single curved sur- faces, hence : Radius, multiplied by index and divided by excess index, equals the second principal focal distance, F'. But the refracted rays suffer another break at the second surface which they strike obliquely. To find the final focal distance: Divide F' by the index of refraction to locate F 2 . Or, Radius, divided by excess index, equals F 2 or F 3 . The optical center and one nodal point are at the apex of curvature on the axis, because : Radius, multiplied by lens thickness and divided by sum of radii, equals the distance from plane surface to optical center. 50x7* = _375_ = 7i ints from flat sur f ac e to O. Or, better : 50 -f- oO The nodal point for the curved surface is located by dividing the thick- ness of the lens by the index of the rare medium, 1.00 : 7iH-1.00 = 7 points from flat surface to N' which is at O. A SYSTEM OF MATURE MEDICINE The nodal point for the flat surface is located by dividing the thickness of the lens by the index of the dense medium, 1.50: 7-=-l.oO = 5 points to N. Plano-convex lenses have one flat and one curved surface. They are not used in practice, but are of importance theoretically, because they embody optical principles, hence the story would be incomplete without a descrip- tion of them. The first change resulting from adding- a plane second surface to the single curve is that the second principal focal distance is eliminated, be- cause rays parallel with the axis entering the curved surface are refracted toward what was the second principal focal point of the single curved sur- face and strike the flat surface at an angle, therefore suffer a second re- fraction, which results in shortening that focal distance until it equals the first principal focal distance of the single curved surface. Fig. 33, 1 mm. scale, shows a plano-convex lens as the segment of a globe, the dashed line indicates the circumference. R', approaching parallel with the axis, is refracted at the first surface and passes through the lens in the direction F' toward a point 90 mm. from the surface on the axis, as if it came from x, because the radius, multiplied by the index and divided by the excess index gives that figure. At the second surface the perpen- dicular, P, a, P, is drawn, with its parallel, PI, fixed by measuring the angle of incidence to the second surface, measured at b, 1, continued 1^ to PL The distance from b to a, duplicated from a to c, fixes the point on the line PI where the final course of the ray will cross on its way to F 2 . To calculate this distance without using the perpendicular-parallel method : Divide the long focal distance of the first surface by the index of refraction of the dense medium. This is particularly valuable if the index is 1.523, or some other fraction than 1.50. R 2 , entering the plane side parallel with the axis is perpendicular to the flat surface and passes without refraction ; at the second surface it is refracted as in single curved surfaces, so that the effect is the same as the two refractions give to the ray going the other way. REFRACTION BY PLANO-CONVEX LENSES Divide the radius by the excess index of the dense medium to get the focal distance, for parallel rays leaving the dense medium. The second change exhibited by the lens is in the location of the optical center, which is the crossing point of secondary axial rays. Fig. 34, 1 mm. scale, shows how to find it. The axial line P', is the perpendicular to the curved surface, and P 2 , parallel with P', is a perpendicular to the flat surface. The oblique line, passing through the lens and connecting P 2 with P', is the refracted section of a secondary axial ray. R', striking the surface at O, going in the direction x 2 , is refracted as if it came from a, going toward b, striking the flat surface at the line P 2 ; and, being refracted again, passes to R 2 as if it came from x, and as if it had crossed the principal axis at N. This point, N, may be located by calculation : Divide the thickness of the lens by the index of the dense medium, and the product will be the distance from the flat surface to N in the lens. This point is called a nodal point, which is denned as the point on the principal axis where secondary axial rays would cross if they were not refracted. The nodal distance from flat surface, multiplied by the index of refraction, locates the optical cen- ter, O. Fig. 35, 1 mm. scale, shows how the nodal point may be found by the Perpen- dicular-Parallel method : The ray R' ap- proaches the surface in the direction x' and striking it at the axial line, P', is refracted toward b as if it came from a, and at the second surface is broken again, passing to R 2 as if it came from x 2 , and crossed the axial line at N. The dis- tance from 1, on R', to O, is duplicated in the distance from O to 2, on PI', and the distance from 3, on the dashed line to O 2 , on P 2 , is duplicated by the distance from O 2 to 4, on PI 2 . It has been shown that the angle of reflection equals the angle of inci- dence, no matter what the index of refraction. This law plays an important part sometimes, as is illustrated in Fig. 36, 1 mm. scale, R is the in- cident parallel ray, the line P C is the perpendicular from the center of curvature, Rf is the reflected portion of R and passes away from the lens as if it came from NF on the axis. This is the negative focal point by re- flection from a positive surface. The cardinal points of any lens are: First, the principal points, where 44 A SYSTEM OF MATURE MEDICINE the principal axis cuts each surface; second, the optical center; third, the nodal points; fourth, the principal focal points. The cardinal planes are lines crossing the axis at right angles, at the cardinal points. To construct a plano-convex lens there are to be considered : The index of refraction; the power desired; the radius of curvature; the thickness of the lens. Having the index and principal focal distance wanted, to get the radius necessary, multiply the focal distance by the excess index of the dense medium. Having the index and radius, to get the principal focal distance, divide the radius by the excess index of the dense medium. Having the radius and principal focal distance, to get the excess index, divide the radius by the focal distance. Thus, with an index of 1.52 and a focal distance of 50 cm. wanted : 50x .52 = 26 cm., the radius. Or, having the index and radius, 1.52 and 26 ; to find the focus : 26-f- .52 = 50, the focus wanted. Or, having radius, 26, and focus, 50, to find the excess index : 26-^50 = .52, the excess index. To utilize the principles further it is convenient to have a unit of value, which has been established as a lens having a principal focal distance of one meter, (100 centimeters, 1,000 millimeters). It has been given the name Diopter, needlessly, because, when we give the sign -(- or , and the figure representing the unit, that is sufficient ; then the word "diopter" means, literally, "to see through," and does not mean a unit of measure. Sometimes it is necessary to make a false statement in order to give force to a truth. Under Fig. 32 such a false statement is made in showing how the second principal focal distance of a single curved surface is elim- inated by adding a second surface, making a lens. It was shown there that the second break, suffered by R' at the flat surface brought the focal point to the same distance from the surface that R 2 was brought by one refraction at the curved surface. This is not true, except when we disregard the thick- ness of the lens, which Nature does not do. -IV- /So REFRACTION BY PLANO-CONVEX LENSES Fig. 37, 1 mm. scale, shows R', paralleling the axis as it approaches the lens, is broken toward F', 90 mm. from the first surface, or the optical center; at the second surface it suffers another break and passes away to F 2 , 60 mm. from the nodal point, N, instead of from the first surface, because that is where the secondary axial ray leaves the axis. This is a third change made by lenses. The principal focal distance on the curved side is still measured from the surface because the optical center is there. It is also a nodal point. R 2 would only suffer refraction at the curved surface and would focus 60 points beyond it.- See Figs. 34 and 35 for reasons for measuring from N to F 2 . The fourth change made by lenses is that while in single curved surface refraction measurements could be made from either the surface or the optical center. In lenses we have to stick to optical centers and nodal points. In the matter of focal distances, all lenses are compared with the stand- ard. Fig. 38 may help make the point clear. Let -f L be the position of convex lenses and the points on the axis show the principal focal distances from the lens, 1 millimeter representing 1 centimeter. The top row of figures are all multiples of 1 and indicate the various powers of lenses stronger than 1. Any of these figures, divided into 100, the focal length of + 1. (usually written -(- 1.00 because there are fractions sometimes)., will give the corresponding figure below the axis, which is the focal length of that lens. Also, any of the lower figures, divided into the standard, 100, will give the corresponding unit in the row above. The same is true of any other system of numbering lenses. Some use the inch system, in which, to be exact 39.37 inches must be the unit, because that is exactly 1 meter. But, any focal distance, divided into that unit will give the unit, of power of the lens ; and any unit of power, divided into the above figure will give the focal distance exactly. On account of its small subdivisions in tenths, the metric system is preferable. In the matter of conjugate focal distances and their relations, in plano- convex lenses, we have : 1. The principal focal distance and one conjugate focal distance being known, to find the other conjugate focal distance: Multiply the given con- jugate focal distance by the principal focal distance and divide by the differ- ence between them. Or, express both distances in units and subtract the less from the greater, then find the principal focal distance of the difference, which will be the second conjugate focal distance. Thus, if we have a principal focal distance of 25 cm. and one conjugate focal distance of 100 cm. : 46 A SYSTEM OF MATURE MEDICINE 100x25 = 2,500 00 , ~, ,. L ioo 85 = 75 = ^ cm '' second Cf distance. Or, 25, divided into 100, equals 4 units ; 100, divided into 100, equals 1 unit; the difference is 3 units; and 3, divided into 100, gives 33i. 2. Having both conjugate focal distances, to find the principal focal dis- tance: Multiply the two given distances together and divide by their sum: ' = 25 ' the P rinci P al f ocal distance. Or, express the given distances in units ; add them ; convert the product to focal distance: Thus, 100 equals 1.00; 33^ equals 3.00; add them, makes 4.00, and 100, divided by 4, equals 25, the principal focal distance. 3. Having the two conjugate focal distances and the radius, to get the excess index: Find the principal focal distance, as above, then divide the radius by it. 4. Having the two conjugate focal distances and the index, to get the radius : Find the principal focal distance, as above, and multiply it by the excess index. An interesting exhibit by lenses is the relationship between two sets of conjugate focal distances. For example : Being given two first conjugate focal distances and the ratio of change in the two second conjugate focal distances by shifting the object from one of the two given distances to the other and being required to find the second conjugate focal distances and the power of the lens, there are two sets of procedures, each requiring two calculations. One is when the object is first placed at the farthest first conjugate focal distance and is moved to the nearest one. The other is when the object is first placed at the nearest first conjugate focal distance and is moved to the farthest one. In each the first calculation gives the second conjugate focal distance corresponding to the last position of the object, and the second gives the power of the lens. First, express the given conjugate focal distances in units and find their difference; multiply the principal focal distance of that difference by the times, the second second conjugate focal distance is to be greater, or less, than the first second conjugate focal distance; this will give the second second conjugate focal distance, corresponding to the last position of the object. Second, express this distance in units and add them to the units of the object distance, to get the poiwer of the lens. Second, to prove the correctness of such a calculation, find the first second conjugate focal distance by dividing, or multiplying, the second second conjugate focal distance by the times greater, or less, specified in the question ; express the result in units and add to the units of the cor- responding first conjugate focal distance, to get the power of the lens. If the result is the same as in the other calculation the solution is proved. To make this plainer: Suppose an object be placed 100 cm. from a lens and is then moved to 50 cm. from it, with the result that the second con- jugate focal distance is three times greater than the other second conjugate focal distance, corresponding to the first position of object; what are the two second conjugate focal distances and what is the power of the lens? REFRACTION BY PLANO-CONVEX LENSES 47 Fig. 39, ^ mm. scale, will help illustrate this. The first position is 100 points; the second one is 50 points. Let each point represent 1 centimeter. 100 = 1.00; 50 = 2.00; the difference, 1.00 = 100 F'. The change of position is said to make the second conjugate focal dis- tance three times farther, therefore : 100x3 = 300, the second second conjugate focal distance, or .33^ units, which, added to the units represented by the second first conjugate focal distance, 50, which is 2.00, we have the power of the lens, 2.33^. As the second second conjugate focal distance is three times farther than the first second conjugate focal distance, it is four times as far: 300-^-4 = 75, the first second conjugate focal distance, or 1.33^ units, which, added to the units represented by the first first conjugate focal dis- tance, 100, or 1.00, gives 2.33^ as the lens power. Reversing the proposition, making 50 the first position and 100 the sec- ond and the change to make the second second conjugate focal distance one- fourth as far as the first second conjugate focal distance, we have : 50 cm. equals 2.00; 100 cm. equals 1.00; the difference, 1.00 equals 100 cm. F'. The change reduces the first second conjugate focal distance to one-fourth, a reduction of three-fourths, therefore : lOOxf = 75 cm., the second second conjugate focal distance or 1.33 units, which, added to the units represented by the second first position, 100, or 1.00, gives 2.33^ units as the power of lens. The second second conjugate focal distance is one-fourth of the first second conjugate focal distance, therefore: 75x4 = 300 cm., the first second conjugate focal distance, or .33% units, which, added to the first first conjugate focal distance, 50, or 2.00, gives 2.33| units, the power of lens. In making drawings to show conjugate focal points it is necessary to use the law of single curved surfaces to get the direction of the ray while passing through the lens. All so-called "authorities" have neglected this, and I have traced their error back as far as 1806, to "Adams' Philosophy," where he shows refraction at only one surface, as all the rest have done since. Whom Adams imitated I do not know. H Fig. 40, 1 mm. scale, shows a ray R', R 2 , passing from F to F 2 . Its first refraction takes it toward F', because the first conjugate focal distance, 60, multiplied by the second principal focal distance, 45, and the product, 48 A SYSTEM OF MATURE MEDICINE 2 TOO, divided by the difference between the first conjugate focal distance, 60 and the first principal focal distance, 30, which is 30, gives 90 as the dis- tance from the first surface of the lens to the point on the axis toward which the ray would be directed while passing the lens. F' indicates the course. To get the final course of the ray to F 2 , divide the conjugate focal distance F' already found, 90, by the index of refraction, 1.50. Or, multiply the first conjugate focal distance by the principal focal distance and divide the product by their difference. In Fig. 40 the Base-Line method is used to find the course of the ray from the first surface. It is drawn through the optical center for con- venience, although it might be placed anywhere, just so it is parallel with the incident ray. The perpendicular to the surface at the point of refraction on P 4 is 12 points long to the Base-Line, B B , 12x1.50 = 18-=- .50 = 36 points from the mark in the lens, (which is 12 points from 12), to F' on the Base-Line, which is the course of the ray while passing the lens. Another Base-Line, paralleling the refracted ray, could be used to complete the drawing, but it is left out because the perpendicular from the second surface would fall on the refracted section and probably cause confusion ; also because it affords opportunity to remind the student that there are two ways to do almost everything and sometimes it is best to employ both. Or, the guide-line A A from where the incident ray crosses the principal focal plane through the optical center could be used and the final course of the ray will be found parallel with it. The relative sizes of objects and their images formed by lenses are in the same ratio as their respective conjugate focal distances. In Fig. 40 the object and its image would be of equal size, because the distances from the optical center on the one side and from the nodal point on the other are the same. All spherically curved lenses have the same power in all meridians, hence revolving them on their axes, directed toward any object one surface faces, would make no difference in their image-forming capacities. Another form of plano-convex lens is made with one flat and one cylin- REFRACTION BY PLANO-CONVEX LENSES drically curved surface. As a spherical lens is a segment of a sphere, so a cylindrical lens is a segment of a cylinder. In Fig. 41 the circles mark the cylinder, with the line c c its axis ; 1 and 2 mark the surfaces of the segment; the dotted parallel lines from 1 and 2 show the meridians on the two surfaces which parallel each other and cor- respond to the axis; no other meridians of the curved surface are without curve, but some have more than others. To make this point clearer Fig. 42 is submitted. It shows a plane with the curved surface, x marking the meridian without curve, and the entire surface, meas- ured on the lines 2, 2, 2, etc., paralleling x are as flat as x, although the two surfaces of the lens are nearer together as they re- cede from the axis, the line x, because of the curve at right angles with the axis, as shown in Fig. 41. The meridian M and the lines 1, 1, 1, etc., paralleling it, have exactly the same curvature, the thickest .part of the lens being on the line x. Note particularly that the meridian x has no power and that meridian M has the maximum power; all of the other meridians, a few of which are marked by the oblique lines, have power in pairs of equal value, that is, any two meridians at the same distance from the axis, x, one on each side, have the same power, gradually increasing as they increase their distances from the axis until they approach M, where they have almost the maximum power ; at a point half way between x and M there is one-half of the maximum power, hence, two cylinders of the same kind and power, superimposed, with their axes at right angles, will give the effect of a spherical lens. If not exactly at right angles the effect will be that of a sphero-cylindrical or compound lens, a description of which will be found in another chapter. Cylindrical lenses have no image-forming capacity. Revolving a cylindrical lens around its axis would be like turning a vertical section of a barrel around a post placed where the center of the barrel would be; at the first quarter turn the edge of the lens would be to- ward the object it faced in its first position. What is ordinarily termed the axis of a cylinder is an axial line, which is, at the curved surface just the radial distance from the real axis, as the surface of a .spherical lens is the radial distance from the center of the globe from w r hich it was cut. Rotating a cylindrical lens around a spherical axis has the effect of distorting objects seen through it. Fig. 41 shows how a cylindrical lens focuses rays on line 3, a plane with the axis, and c, c, c, c, represent a ribbon of light passing the axis without refraction, other ribbons, approaching parallel with this one. above and below it, will be broken to it at the line 3. Of course the use of the world "focus" for anything but points is a misnomer, but it is permissible in optical work. A SYSTEM OF MATURE MEDICINE Fig. 4:3 shows -j- and -- plane cylindrical lenses as they come from the factory uncut ; that is, not in the form of a lens. This is for the convenience of the optician, who cuts lenses by patterns of different sizes. By placing the patterns in different positions the axial line is fixed in the position in- dicated by the prescription, so that the maximum curve will be where it is needed, when the other curves will fit according to Natural law. Some- times the plane surface of a cylindrical lens is put on a machine and changed to a spherical surface, when the lens becomes a bi-curved or sphero-cylin- drical lens, with power in all meridians of one surface and with unequal additions to them on the cylindrical side. Another chapter will consider such lenses. CHAPTER V. Refraction and Reflection by Piano-Concave Lenses. Fig. ~W- ^ mm. scale, shows the principal focal points, optical center and nodal points of a plano-concave lens. Rays R 2 , entering from the plane side, parallel with the axis, only suf- fer refraction at the curved surface, at which they are broken from the axis instead of toward it, as in plano-convex lenses ; but the rule applies, only with negative effect : Radius, divided by excess index, equals F a , and the rays leave the lens in the direction R 2 on the left as if they came from F 3 on the right. Rays R', entering from the left, are refracted at the first surface as if they came from F' because that is the long focal distance of the single curved surface : At the second surface these rays are broken again, from the axis, as if they came from F 2 , because : F'-j-I = F 2 . The optical center and one nodal point are at the apex of curvature on the axis for the same reasons they are in plano-convex lenses. See Fig. 32. The other nodal point, X, is found in the same manner as for plano- convex lenses. See Fig. 32. Plano-concave lenses have one flat and one curved surface. They differ from plano-convex by being 'thinnest on the axial line while the plano-con- vex are thickest on that line. There are some other points of difference, as A SYSTEM OF MATURE MEDICINE a result of their form, which make consideration of them a necessity to ex- pound optical principles. 1 i.ot Fig. 45, mm. scale, shows that a plano-concave lens is not a segment of a globe, but is a piece of flat glass with the form of the globe segment ground into it. The optical center and nodal points are found in the same manner as for the plano-convex. The optical center is at the apex of the curved sur- face on the axis in both instances. But the nodal point in Fig. 37 is inside of the curvature representing the globe, while in Fig. 45 it is outside of that curvature. The result is that F', in each figure, is 90 points from the curved surface, while F 2 , Fig. 37, is 61^ points from the curved surface and in Fig. 45 it is only 59 points distant. In Fig. 45 the principal focal points are nega- tive; R' and R 2 representing the parallel rays entering the curved side, and after being refracted at each surface, emerging divergent from the axis. Fig. 46, mm. scale, shows rays R' entering the flat surface and being refracted only at the curved surface, pass away divergent from the axis as if they came from F', 60 mm. from O, because that is the only refracting surface in this instance. REFRACTION BY PLANO-CONCAVE LENSES 53 Fig. 47, mm. scale, shows how to find the optical center and nodal point of a plano-concave lens. The axial line is P' to the curved surface and P 2 is the perpendicular to the flat surface; the two perpendiculars must always be parallel; the oblique line, in the lens, course D D, which connects P' and P 2 is the refracted section of a secondary axial ray: Drawing- the line PI parallel with the axis, P', and measuring the angles 1 and l, the direction of the ray R' is found, pas- sing from the optical center, (which is also one of the nodal points), as if it came from x' ; the direction R 2 is, of course, parallel with the course R' r hence passes from the lens as if it came from x 2 and crossed the axis at N, the nodal point. This nodal point is also located by dividing the thickness of the lens by the index of refrac- tion of the dense medium and the quotient gives the distance from the flat surface to the point. Also multiplying this distance by the index of refrac- tion, gives the location of the optical center and the other nodal point. Fig. 48, mm. scale, shows reflection by concave lenses. R', approaching parallel with the axial line, is reflected on the opposite side of the perpen- dicular, P', and follows R' to the axis at F'. This is the positive principal focal point and shows that the principal focal distance, by reflection, of a concave surface, is one-half its radial distance. R 2 is drawn to show that the refracted portion of the ray would pass away, R 3 , as if it came from F 2 , afte r being refracted twice by the surfaces of the lens ; but that the reflected por- tion, R 2 , would go to the principal focal point. The cardinal points and planes of plano-concave lenses are located ac- cording to the laws given in Chapter IV, folowing Fig. 36. Also the same rules of construction are followed, with negative results where they are positive in the plano-convex and with positive results where they are negative in the plano-convex. Concave lenses are numbered according to the corresponding convex lens, therefore, they are theoretically the exact opposites; but this is not true, practically, as we shall see. However it makes no difference in the physiological value of such lenses as we will select from the various forms and recommend for use in practice. After having established the principal focal distance, by reflection, of concave surfaces, and understanding that it is only by single curved surfaces 54 A SYSTEM OF MATURE MKDICINE images are formed by reflection, the rules of calculation for conjugate focal distances for convex lenses apply equally well for concave surfaces. It is worthy of mention that a plano-concave lens of the same radius as a plano- convex, will focus by reflection at one-fourth the distance the convex will focus by refraction, provided the index is 1.50. With any other index there will be a change., because the focus by reflection does not change with a change of index, while the focus by refraction does. Fig. 49, mm. scale, not only shows the principal focus by reflection, but the conjugate focuses and the formation of image. The ray 1 approaches parallel with the axis and is reflected to the principal focal point, PF, passing on to meet ray 2, starting from the same point at top of object and approach- ing the surface from C, the center of curvature is reflected straight back. Ray 3 is perpendicular to the surface and is reflected straight back ; it meets ray 4, which is reflected as 4, meeting ray 3 at 40, the second conjugate focal distance. O is the object, I the image; A A are angles of incidence and of reflection ; B B are the same ; P is the perpendicular for angles A and 2 is the same for angles B. 120X30 = 3600-H120 30)90 = 40, second Cf. Or, 30 cm. equals 3.33^ units; 120 cm. equals, .83i units. 3.331 .83$ = 2.50 = 40 cm. second Cf. Real images are formed by refraction through convex lenses. Real images are formed by reflection from concave lenses. In both instances the images are inverted. Figs. 27 and 28, Chapter III, showed how concave and convex single curved surfaces exhibit virtual objects. Now we shall have virtual objects bv concave lenses. I. So Fig. 50, mm. scaje, shows why objects seen through a concave lens ap- pear nearer and smaller. O' is the real object; the ray 1 starts from a point REFRACTION BY PLANO-CONCAVE LENSES on the axis and is broken at the first surface so that it passes through the lens as if it came from F', because : (Cf'XNPF)-KCf'+OPF) = F'. The radius, 30, multiplied by the index, 1.50, equals- 45, and this, divided by the excess index, .50, gives 90 as NPF; hence: (90X90) = 8100-^ (90+60)150 = 54, or F'. To get the final course of the ray we have : 54-f-1.50 -= 36 = F 2 . The opposite principal focus of this lens would be 60, as shown in Fig. 46, therefore : (90X60) = 5400-K90+60)150 = 36, or F 2 . Ray 2 approaches parallel with the axis and is broken at the first sur- face so that it passes through the lens as if it came from the long focus, 90, indicated by the line a; the second break, at the flat surface, sends the ra} away as if it came from the principal negative focus, 60, indicated by the line b, which makes it appear to come from the top of the virtual object, just as it actually came from the top of the real one; hence the virtual object is nearer and smaller than the real one. In Chapter IV under Fig. 41 cylindrical convex lenses have been de- scribed. The same description applies, negatively, to - - cylinders shown with the -j- in Fig. 43. For all practical purposes in ophthalmology it is unnecessary to figure focal distances from the nodal points ; but in the study of principles it is very essential to be familiar with the absolute facts. Plano-convex and plano- concave lenses are not employed in practice, except when cylinders are used alone. The dioptric power represented in the difference between the curved surface and the nodal point in the lens is so insignificant that in all piano- curved lenses it is sufficiently accurate to measure the focal distance on either side from the principal point on the curved surface. Even then one of the focal distances will be correct, namely, the one on the curved side for -J- and that on the flat side for . This is because one nodal point and the optical center are at the principal point and rays refracted by the + curve as they pass out of the lens are focused positively on that side, while those refracted by the - - curve as they pass out of the lens are focused negatively on the reverse side. The same liberty may be taken with bi-convex or bi-concave lenses ; but measures should be taken from the middle of the lens, on the axis, where the optical center is located. Neither focal distance will be correct in such instances, because, as will be shown in the next two chapters, the absolute distances are measured from the nodal points. In -4- lenses there is a dead space between the nodal points, and in - - lenses that space is used twice, because such lenses have negative focal distances and each distance is measured backward from the nodal point of the last refracting surface. "With meniscus lenses it is a different matter, as will be shown in Chapter VIII. Both nodal points and the optical center are outside of such lenses, -|- or , as usually formed. For -4- lenses the focuses of which are positive, one of the absolute measures, that on the side, is taken from the 56 A SYSTEM OF MATURE MEDICINE optical center, and that for the - - side is made from the nodal point nearest the lens. For lenses, the focuses of which are negative, the focal distance for the surface is measured absolutely from the optical center to the negative focal point on the -j- side of the lens, and that of the -f- side is measured from the nodal point nearest the lens to the negative focal point on the side of the lens. Thus, the space between the optical center and the nodal point nearest the lens is utilized twice in meniscus lenses while it is a dead space in -f- lenses of the same class. In either case it is entirely wrong to measure from the middle of the lens or from either surface. The deeper the meniscus form of the lens the worse the fault. In measuring meniscus lenses the nodal point farthest from the lens is never used. We have found some writers calling it the optical center but they are very muck mistaken. Optical firms recommend meniscus and "toric" lenses, because there is more profit in selling them. They are so ignorant of optical principles they have never discovered their inconsistency in making the lenses for trial sets bi-convex and bi-concave. Alleged optical and ophthalmological journals fairly reek with adver- tisements of such lenses and with articles exploiting prisms and one-eighth diopter lenses when not one in a thousand of them could make a correct drawing of a lens if a fortune were the stake, not one in a thousand ever came within one-half diopter of the exact amount of eye error, except, pos- sibly, an accidental case now and then, and not one in a thousand could show the physiological action of a prism if they knew they wouldn't use them. CHAPTER VI. Refraction and Reflection by Bi-Convex Lenses. Fig. 51 shows the principal focal points, optical center and nodal points of a bi-convex lens. This is a reduced cut and should be made on radii of 40 mm. to fit the figures given. Good practice for the student. Rays R', entering from the left are refracted at the first surface and go toward F' while passing the lens, as if they came from X', because : Radius, multiplied by index and divided by excess index, equal F'. The same explanation applies to rays R 2 , which go toward F' on the left as if they came from X 2 . To locate points F 2 in each of the above instances : The distance from the second surface to F', multiplied by the first principal focal distance 'of that surface, 80, and divided by the sum of the distance from that surface to F' and the second principal focal distance of the surface, 120, will give F 2 . Thus: 120 -- lens thickness, 6, leaves .114. 114x80 = 9,120 001 14/ t r T72 120 234 = /117 mm - from second surface to F 2 . To locate the optical center: The thickness of the lens, multiplied by the short focus of either surface and divided by the sum of the short focuses of both surfaces, considered as single curved surfaces, gives the distance of the optical center from that surface represented by the first figure. Thus: 6 X 80 = 480 r , , =3 mm. from either surface to O. 80 -j- 80~ 160 A SYSTEM OF MATURE MEDICINE Or radii 40-J-40 = 80 and 4 % f thickness of lens fiom either sur- face to O. To locate the nodal points : The optical center distance from either surface, multiplied by F' of that surface and divided by F- less the dis- tance from optical center to surface gives the distance from that surface to its nodal point. Thus 3 x so = 340 =0% f rom e i t h er surface to N. 120 3 =. 117 The real principal focal distance is 38 11 % 17 -f-- ( Ki7 == from N to F 2 . In dealing with single curved surfaces the optical center was the center of curvature. In plano-convex and plano-concave lenses the optical center took a position at the apex of curvature. In single curved surfaces there were no nodal points, because the sec- ondary axial rays suffered no refraction and crossed the principal axis at the optical center. In plano-convex and plano-concave lenses the secondary axial rays crossed the principal axis at the new optical center, but suffered refraction at the flat surface and passed away as if they came from N, (Figs. 34, 35 and 47), thus fixing one nodal point for piano-curved lenses. Fig. 52, mm. scale, introducing bi-convex lenses, brings us back to the single curved proposition, so far as optical center and nodal points are con- cerned. They are all at one place on the axis, namely, the center of cur- vature. The drawing is not as complicated as it may appear at first to the stu- dent. The principles involved have been given in the chapter on single curved surfaces, and this figure will help illustrate the continuity of law. Considering each surface, A and B, of the circle, as single curved sur- faces, we have, with index 1.50, principal focal distances F' at O and at I. Therefore rays 1 and 1, starting from the axis at O, are rendered parallel by the surface A. and pass through the globe parallel with the axis. Re- fracted again at the surface B, they are converged to the point F' and I. The secondary axial rays from X' and X 3 to X 2 and X 4 pass through the globe without refraction, because they strike both surfaces perpendicularly. The rays 2 and 2 from X' are refracted at the surface A and pass to the surface B parallel with the secondary axis starting from the same point ; and after refraction at the second surface, converge to a point at X 2 . Rays 3 and 3 REFRACTION BY Bi-CoNVEX LENSES undergo the same experience and focus again at X 4 . Rays starting from other points on the object, O, above the axis, would focus in the same man- ner below the axis at corresponding points, fixed by their secondary axes, and other rays starting from points on the object below the axis, would be focused at corresponding points above the axis at I, thus completing the image. Again, rays 2 and 3, approaching the A surface from the top and bot- tom of the object, are parallel with the axis. They are refracted at the first surface and take the course F 2 A, because the radius, multiplied by the index and the product divided by the excess index, gives that point as the second principal focal distance of surface A. At the second surface they are refracted again and pass away, toward the points X 2 and X 4 , the first principal focal points of surface B, (radius divided by excess index equals first principal focal distance), measured on their respective secondary ax,es. Note that 2 and 3 cross each other at FG. This is the principal focus of the globe. Rays 3 and 2, from X 4 and X 2 , parallel with the axis on side B, are first directed toward F 2 B and finally toward X 3 and X' crossing each other at FG on the A side, for the same reasons. The image is inverted because the secondary axial rays and their accompanying edge rays cross the prin- cipal axis between O and I, the secondary axial rays crossing at the optical center and all the others between the two points FG, the principal focal points of the globe. The focal distances are measured from the optical center; hence the object is at twice the principal focal distance of the re- fracting system and the image is the same distance on the other side. This is only true absolutely with globes and single curved surfaces, where me.is- ures are from the optical centers. Bi-convex lenses are made: (a), both surfaces spherical; (b), one sur- face spherical and the other cylindrical. In refraction by single curved surfaces, with the center, of curvature as the optical center, the principal focal distances, measured from the surfaces, were in the same relation as the two indexes of refraction ; the long focus being in the dense medium, and the short one in the rare medium, for positive surfaces. Measuring from the optical center the reverse would be true, the short focus would be in the dense and the long one in the rare medium. Using negative surfaces, these are reversed: Measuring from the surfaces the long focus is in the rare medium and the short one in the dense; but. measuring from the optical center the long focus is in the dense and the short one in the rare medium. These points must be watched, as they are tricky. In refraction by plano-convex and plano-concave lenses the two principal focal distances become equal, measured from the optical centers and the nodal points. In bi-convex lenses the optical center takes a new position, between the surfaces. If the radii are equal it will be midway between them. If they are unequal it will divide the space in proportion to the radii, taking a position nearest the stronger curve. Fig. 53, mm. scale, shows a bi-convex lens with C' and C 2 as the cen- GO A SYSTEM OF MATURE MEDICINE \ ters of curvature; the line connecting them and bisecting the circles is the axis, on which all of the cardinal points are located. This lens is the same as two plano-convex lenses with their flat sides together, so it appears that if either would focus at twice the radial distance, if standing alone, putting them together should double the power so \ V AWfj^^** / the principal focal distance would equal one radial dis- tance. But this is not true. In this figure the optical center and nodal points are located by erecting the perpendiculars, P' and P 2 , to surfaces 1 and 2, parallel with each other; then the oblique line, in the lens, connecting the two perpendiculars and the two surfaces, crosses the principal axis, locating the optical center midway between the surfaces. Measuring the angles formed with the respective perpendiculars by the refracted section, as indicated by the index of refraction, and increasing them for R' and R 2 , outside of the surfaces, we have the course of R' as if it came from X 2 and crossed the axis at N, and the course of R 2 as if it came from X' and crossed the axis at N. Thus we establish two nodal points for bi-convex lenses and it will be found that all bi-curved lenses have two nodal points. The lines marking the points in the drawing are the planes. x In Fig. 54, mm. scale, we have a bi-convex lens with two radii of 20 points each, the same as in Fig. 53. The rays 1 and 3, approaching parallel with the axis, are refracted at surface A toward F 2 on the right, which is the long focal distance of that surface, regarded as a single curved surface, the index being 1.50, (20X1.50-=- .50 = 60) ; at the second surface this distance is shortened the thickness of the lens, 6, leaving 54 points from the second surface to F 2 , and this distance, multiplied by the short focal distance of the surface B, considered as a single surved surface, the product divided by 54 -(- the long focal distance of surface B, gives the final distance to F' : 54X40 = 2160-f-(54-f 60) 114 =18.9474 mm. "the principal focal distance from the second surface to F'. Another way to locate F' is that employed in Fig. 52, where a ray ap- proached the surface parallel with the axis, or divergent from the axis, and passed through the dense medium parallel with a secondary axis, the final focus on that secondary axis would be at the first principal focal distance of that surface. In this instance R' and R 3 are parallel with the secondary axes from X' to X 2 and from X 3 to X 4 while passing the lens, hence they focus on those lines at X 2 and X 4 , and to do so must cross each other at F'. REFRACTION BY BI-CONVEX LENSES 61 The same proceedings applied to rays 4 and 2 approaching the lens from the right side, establish F 2 and F' on the A side and finally end at X 3 and X', the conjugate focal points with X* and X 2 . Locating the nodal points by calculation : The distance to either surface from the optical center, multiplied by F' of that surface and the product divided by F 2 less the distance from O C to surface, gives the distance from that surface to its nodal point. Thus : 3X40= 120-r-(60 3)57 = 2.1052 mm. from each surface to the nodal points in Fig. 54. Adding this to the principal focal distance found from each surface, we have 18.9474+2.1052 = 21.0526 from N to F'. This is 4.95 mm. beyond the center of curvature of the first surface. A simple way to locate the optical centers of bi-convex lenses is to add their radii to get the denominator of a fraction of which the numerator is one radius, and this fraction of the thickness of the lens, measured from the surface represented by the numerator, is the distance to the optical center. Thus, in Fig. 54, with radii 20, their sum is 40, hence 2 % of the lens thick- ness from either surface is the location of the optical center. If one radius was 20 and the other 30, their sum would be 50, and 2 % from one surface or 3 %o from the other would be the same as % and % ; the first would be the distance from the strong surface and the second the distance from the weak surface to the optical center. Another method is : One radius multiplied by the thickness of the lens and the product divided by the sum of the two radii, equals the distance to the optical center from the surface represented by the radius multiplied. Thus, Fig. 54 the lens is 6 points thick : 20X6 = 120-^(20+20)40 = 3 points to O C. If one radius was 20 and the other 30, it would be : 30X6=180-=-(30+20)50=3% points to O C from weak side. Or, 20X6 = 120-H20+30)50 = 2% points to O C from strong side. In Fig. 54 the dashed lines, divergent from O, on the axis, to the edge of the lens, and convergent to I on the axis after passing the lens, are parallel with the axis while passing the lens, hence the object and image are at the first principal focal distance of the respective surfaces as in Fig. 52, but the actual principal focal distance of the lens is at F' on each side, midway between the object and the nodal point on side A, and midway be- tween the image and the nodal point on side B. The space between the" nodal points is dead. The optical center is not used in measuring the focal distances in bi-curved lenses, + or , except- ing meniscus lenses, of course. Note, Fig. 54, that the secondary axial rays from X' and X 3 are directed toward N inside the A surface. They are refracted at the first surface and broken again at the second surface, after which they pass away as if they came from N inside the B surface. Their courses on opposite sides of the lens are dashed to show the amount of the deviation. Comparing Figs. 52 and 32, we see that with the index 1.50 the principal focus at FG, Fig. 52, is a change from F-, Fig. 32, where a segment of a globe is used. A SVSTEM OF MATURE MEDICINE Comparing- Figs. 52 and 37, we find that in 62 the optical center has changed from the apex of curvature back to the center of curvature as in single curved sur- faces. The nodal point developed in Fig. 37 is lost in Fig. 52. In Figs. 53 and 54 we have found two nodal points and that focal distances are measured from them to the exclusion of the optical center, while in Fig. 37 the focal distances were measured from one nodal point and from the optical center. There will be other changes as lenses take other forms. Fig. 55, mm. scale, is for the purpose of explaining methods of finding conjugate focal distances for bi- convex lenses. The ordinary procedure is to: Multiply the first conjugate focal distance by the principal focal distance and divide the product by the difference between the first two figures. Or, multiply the two principal focal distances together and divide the product by the difference between the first conjugate focal distance and the principal focal distance on the same side ; then add the product to the principal focal distance on the other side. Thus, for Fig. 55, index 1.50, radii 20, there would be a principal focal distance of 20 ; and, CP 100, multiplied by 20 and the product divided by the difference between them, would give 25 points as the second conjugate focal distance, or Cf 2 ; but this is not a fact. First, we must locate the optical center and the nodal points : \Ye have seen that when the radii are the same the optical center is midway between the surfaces, hence, in this instance 2 points from either surface. Following the rule given at the beginning of this chapter we have : 2x40 = 80 .,-,, . , , ... , AT _ = I 1 yon points from either surface to N. \y\) - Do Second, we find the true principal focal distances : Radius, multiplied by index and divided by excess index gives the long focal distance of the first surfaces; hence : 9QX1.50 = 30-:- .50 = 60. This is shortened by the thickness of the lens, 4 points, leaving 56 from the second surface, and the final calculation is : This distance multiplied by the short focal distance of the second surface and the product &JS divided by the sum of this distance and the long focal distance of the second surface gives the final distance of the ray from the second surface; therefore: REFRACTION BY Bi-CoxvEx LEXSES 56X40 = 2240-=- (56+60) 116 = 19.31032 from second surface. adding- the distance to the nodal pt. 1.38 1 < or-^7T7rr\ from nodal points, we have the principal focal distance, 20.69032 Now for the conjugate focal points: The first one is given, 100. Following the rule for single curved surfaces : = 100 points to F 2 . 100 x 60 =r 6,000 100 40 = 60 Deducting the thickness of the lens, leaves 96, and using the rule last given above : 96 x 40 = 3840 96 + GO = 156 nodal point, = 24.615 from second surface to Cf 2 , adding distance to 1 38 7 from nodal point to Cf 2 . 25.995 The line x x is a secondary axial ray, to show the size of the image com- pared with the object O'. It is the same as the second conjugate focal dis- tance is to the first one. The word "lens" comes from "lentil" a vegetable of the bean family, which is bi-convex ; therefore, speaking strictly, this is the only form of lens entitled to the name ; but, like the word "diopter," it is applied to all spherical and cylindrical segments and their combinations. The bi-convex is, unquestionably, the best form of all because it affords the flattest possible surfaces and is, in every other way, the most practical, being nearer free from aberrations which attend all in greater or less degree. A form of bi-convex lens which is often very useful has a spherical sur- face on one side and a cylindrical surface on the other side. It is called a sphero-cylindrical lens. Fig. 56 illustrates the surfaces of such a lens. A is the spherical side, and the lines crossing the center represent the principal meridians of a normal lens. Those marked 90 and 180 are the first principal meridians, and those marked 45 and 135 are the secondary principal meridians. The spherical surface always has equal power in all meridians; but a compound, or sphero-cylindrical lens never has equal power in all meridians ; the power of the spherical side is always on the meridian corresponding to the axis of the cylinder and furnishes all of the power there is in the combina- tion at that meridian, because the axis of the cylinder is a plane surface. A SYSTEM OF MATURE MEDICINE B is the cylindrical side and the lines c c and x x correspond to the 180th and 90th meridians of the spherical surface and are the first principal meridians; c c is the meridian of maximum power and x x is the axis, which is flat, hence has no power. The oblique lines o o and o o, are the second principal meridians of the cylindrical surface. The latter exhibit one-half of the full power of that surface. The meridians between o and c gradually in- crease in power as they approach c and those between o and x gradually de- crease in power. Considered as a whole, we have the power of the sphere at the meridian on which the axis of the cylinder is placed, arid at the opposite meridian, that is, 90 degrees from the first, or axial meridian, we have the full power of the combination. Thus, in Fig. 56, with axis at 90, we have only the power of the sphere when we place them together; but at 180 we have the curves of both sphere and cylinder. The sphere has equal power in all meridians, the cylinder begins to add to that power in all of its meridians crossing the axis, increasing as they get nearer to a right angle, finally giving full power at 180. This matter will be explained more fully in the chapter on prescription writing. Proportions of Power of Cylinders at Various Degrees from the Axis : 1 .00030 2 .00122 3 .00274 4 .00487 5 .00760 6 .01093 7 .01485 8 .01937 9 .02447 10 .03025 11 .03631 12 .04323 13 .05060 14 .05853 15 .06699 16 .07398 17 .08548 18 .09549 19 .10600 20' .11698 21 .12843 22 .14033 23 .15267 24 .16544 25 .17861 26 .19217 27 .20611 28 .22040 29 .23504 30 .25000 31 .26527 32 .28082 33 .29663 34 .31269 35 .32899 36 .34550 37 .36219 38 .37904 39 .39604 40 .41318 41 .43041 42 .44773 43 .46512 44 .48255 45 .50000 46 .51745 47 .53488 48 .55227 49 .56959 50 .58682 51 .60396 52 .62096 53 .63781 54 .65450 55 .67101 56 .68731 57 .70337 58 .71918 59 .73473 60 .75000 61 .76496 62 .77960 63 .79389 64 .80783 65 .82139 66 .83456 67 .84733 68 .85967 69 .87157 70 .88302 71 .89400 72 .90450 73 .91452 74 .9260? 75 .93301 76 .94147 77 .94940 78 .95677 79 .96369 80 .96975 81 .97553 82 .98063 83 .98515 84 .98907 85 .99240 86 .99513 87 .99726 88 .99878 89 .99970 90 1.00000 CHAPTER VII. Refraction and Reflection by Bi-Concave Lenses. Fig. 57, a reduced drawing to be made to mm. scale by students, shows the principal focal points, optical center and nodal points of a bi-concave lens. Rays R', entering from the left, are refracted at the first surface and go toward X' as if they came from F' on the left. At the second surface they are broken again and pass away as R' at the right as if they came from F 2 on the left. To locate F' : Radius, multiplied by index and divided by excess index, gives F'. Thus : 40X1.50 = 6(M-.50 = 130 F' negative. To locate F 2 : The distance from the second surface to F', multiplied by the first principal focal distance of that surface, 80, and divided by the sum of the distance from that surface to F' and the second principal focal distance, 120, will give F\ negative. Thus . F' on A side -j- lens thickness, 6 equals 126. 126 x 80 = 10,080 r r -r, T- 126 + 120 = ^46 : = - %!' mm> * rom " surface to B F 2 - negative. The same proceeding applies to rays R 2 , resulting in the negative focus at A. To locate the optical center: The same proceeding as for Fig. 51: 6 x 80 = 480 r = -5 mm. from either surface to O. OU -j- ol) = IbU To locate the nodal points: The optical center distance from either sur- GG A SYSTEM OF MATURE MEDICINE face, multiplied by F' of the surface and divided by F 2 plus the distance from optical center to surface. Thus : 3 x so = 240 _ in% 23 mm. surface to N. 120 + 3 = 123 Note that the last formula differs from that for the bi-convex in that the -f- sign is substituted for the in this instance below the line in the last calculation. Note also that to get the final principal focal distance in this instance the distance from the surface A to AN and from B to BN must be deducted from the given distances 40 4 %! ; this is 40 12 % 2 3 less 1 11 % 2 3 leaves 39% 23 or 39%! as the negative principal focal distance. Bi-concave lenses are not segments of globes, but are ground on the curves of globes as if the glass lay between them. The tools with which they are made are segments of globes. Fig. 58, mm. scale, shows the optical center, nodal points, secondary axis and principal focal points (negative) of a bi-concave lens. The optical cen- ter and nodal points are located by calculation for these lenses just as they are for the bi-convex ; but there is a difference in the manner of utilizing the nodal points in the bi-concave lenses. R', approaching the A surface parallel with the axis is broken at that surface and passes through the lens as if it came from F 2 A. At the second surface it is refracted again and passes away as if it came from F' B, 19 l / 2 i points from N on the B side of the lens, because that is the refracting sur- face. The same thing happens to R 2 , which is refracted at the B surface and passes through the lens as if it came from F 2 B ; and after refraction at the second surface it passes away as if it came from F' A, measured from N on the A side. In bi-convex lenses the measurements were all taken from the nodal points to the focal points on their own sides; but these are negative lenses, hence the measurements, while taken from the same nodal points, are reversed in the direction taken. The calculation is made as for single curved surfaces. R' approaches the first surface parallel with the axis, and to find its first course after re- fraction the radius is- multiplied by the index and the product divided by the excess index; thus 20X1.50 = 30-^ .50 = 60 = F 2 A. As the lens is 6 points thick the distance from F 2 A to surface B is 66 REFRACTION, ETC., BY BI-CONCAVE LENSES 67 points. The short focus of B surface is 40 points and the long one is 60. 66x40 2640 = 20 2 %! points from B surface to F' B. 66 + 60 126 The same calculation applies to ray R 2 . The optical center is located in the same manner as for Fig. 51. The nodal points are found by the rule on the preceding page and are l 1 ^! points from each surface. Deducting this amount from the 20 20 1 leaves 19%j points from F' B to N on the B side and from F' A to N on the A side. Bi-concave lenses are made: (a), both surfaces spherical; (b), one sur- face spherical and one surface cylindrical. Fig. 59, mm. scale, shows how virtual objects are formed by bi-cpncave lenses. O' is a real object, at 40 points from the A surface of the lens. The ray, 1, approaches parallel with the axis, is refracted at the first surface and passes through the lens as if it came from F 2 on the same side, because the radius, multiplied by the index and the product divided by the excess index, gives that distance from the surface. At the second surface the distance from F 2 is lengthened 6 points, making 66, which, multiplied by the short focal distance of B surface and the product divided by the long focal dis- tance of that surface, 60 -j- 66, gives : 66X40= 2640-^(60+66)126 = 202%! from the B surface back to F' on A side. Ray 3 undergoes the same changes and leaves the lens as if it came from the same F'. Rays 2 and 4, secondary axial rays, are directed toward N, on the A side, and meet the courses of 1 and 2 at X' and X 2 , thus locating the position of the virtual object. The formation of real images by reflection from concave surfaces has been explained in another chapter, hence needs no further mention here. Fig. 60 illustrates the surfaces of a - - compound, or sphere-cylinder lens. As in Fig. 56, the circle, A, represents the spherical side and B represents the cylindrical surface. The description of Fig. 56 fits Fig. 60 as well, except that the powers are negative instead of positive. There is a law that all regular, non-spherical, curved surfaces have their two principal meridians at right angles. Cylindrical lenses are one exhibit of that law in which the meridian of minimum power is neutral and that one is always on the axial line. Spheres and cylinders may be combined -f- and +, -- and , -- and -f-, -f- and . In any case the cylinder, having no power on its axial line, leaves the full power of the sphere undisturbed ; but on the opposite meridian both exhibit full power, and if both are + or both that is the meridian A SYSTEM OF MATURE MEDICINE of maximum power; if one is -f- and the other the power of the sphere is decreased, sometimes neutralized entirely, and may even exhibit some of the power of the cylinder. Thus, if a + 2.00 sphere be combined with a -j- 1.00 cylinder, axis 90, there would be the power of the sphere at the 90th meridian and at the 180th the power of both sphere and cylinder would combine to give + 3.00 effect. The same would be true if the lenses were , the power at 90 would be 2.00 and at 180 would be -- 3.00. But if the sphere is -(- 2.00 and the cylinder -- 1.00, the effect at 90 would be + 2.00 and at 180 it would be -j- 1.00 only, because the -- 1.00 cylinder would neutralize part of the -(- sphere in that meridian. And if the - - cylinder was 2.00 it would leave the lens neutral in the 180th meridian; or if the cylinder was 3.00 it would not only neutralize the -f- sphere in the 180th meridian, but would give a - - 1.00 effect. The same results would occur in using spheres and -(- cylinders. This is explained in detail in the chapter on prescription writing. . CHAPTER VIII. . Refraction and Reflection by Meniscus Lenses. Fig. 61, a reduced drawing to be made to a scale by students, shows the principal focal points, optical center and nodal points of a positive meniscus lens. Rays R', entering the -(- surface are first broken toward F', 60 points, because that is the second principal focal distance found by multiplying the radius by the index and dividing the result by the excess index. Deducting' the thickness of the lens the distance from the second sur- face : 60 6 = 54. Then following the rule for single curved surfaces, and employing it negatively, we have : Cf x OFF Cf NPF 54 x 80 = 4,320. -= Cf 2 which gives for this case: =65%! to F 2 from second surface. 120 54 = 66 Rays R 2 , entering the - - surface are first refracted toward X 3 as if they came from F 3 because that is the second principal focal distance, negative of that surface. Adding the thickness of the lens the Cf to the -f- surface becomes 126. 126x40 = 5,040 12660 66 To locate the optical center: The short radius multiplied by lens thick- ness, divided by the difference in radii multiplied by index and half of lens thickness added. Thus : - - 20x6 = 120 - = 3 y f (40 20) 20"x 1.50 = 30 + 3 = 33 70 A SYSTEM OF MATURE MEDICINE To locate the near nodal point : The same as above, only substitute long radius in place of the short one; this gives N', measured from the -- sur- face. 40x6=240 , r , (40 -20) 20x1.50 =30 + 3 = 33 = % fl " m ~ *^ tO N ' For the far nodal point: Short radius multiplied by lens thickness, divided by the difference between the radii : 20 x 6 = 120 To get real focal distances: For R' == 65% 4 +7%i = 72%! from N' to F 2 . For R 2 == 76 4 /u 3%! = 72%i from O to F*. Fig. 62, reduced drawing to be made to scale by students, shows the principal focal points, optical center and nodal points of a negative meniscus lens. Rays R', entering the surface, are first broken and pass through the lens toward X' as if they came from F', because that is the second principal focal distance of that surface, negative; at the second surface, which is -f- we make the conjugate calculation, after adding the lens thickness: 60+6 = 66 66 g x8 7 5 ' 280 =97% from + surface to F 2 at the left. 66 120 = 54 Rays R 2 , entering the -f- side, are first broken positively and go toward the point F 3 on the left, because that is the second principal focal distance of the surface; at the second surface, after deducting the lens thickness, we locate F 4 by the conjugate method, negatively. 1206 = 114. 1 !!. X40 fi 7-^ 84 % from surface to F* at the right. 1T4 o(j o4 To locate the optical center : Short radius multiplied by the lens thick- ness; divide by the difference in radii multiplied by the index and half the lens thickness deducted. Thus : to O. To locate one nodal point : The same as above, only substitute long radius in place of the short one. This gives N', measured from the -f- surface. REFRACTION, ETC., BY MENISCUS LENSES 71 40 x 6=240 (40 20) 20 x 1.50 = 30 3 = 27 For the other nodal point : Same as for the = 8% from -f- surface to N'. 20 x 6 = 120 = 6 from side to N 2 . ( 40 -!- 20) 20 For the real focal distances : R' = 97% 8% = 88% from N' to F 2 . R2 = 84% +4% =88% from O to F 4 . Note the points from which focal distances are measured in all forms of lenses. Meniscus means "little moon," and that name was applied to the -form of lenses to be considered in this chapter. It applies properly only to the positive form ; but custom has given it to the negative form as well. There are some very peculiar things about meniscus lenses which will require par- ticular attention to master. Fig. 63, mm. scale, is for purposes of comparison. The large circle forms the surface of the -f- lens and the -|- surface of the one. The -f- lens is completed by the small circle extending outside of the large one and the - lens is finished by the small circle remaining inside the large one. The thickness of the lenses is the same. In making lenses the are much thinner on the axis than -f- of the same power ; but that does not change the facts to be shown here. Note that the optical center is not established by the refracted section of the secondary axial ray, in either case ; but is fixed by the emergent sec- tion on the strong side of the lens in both cases. N' is the course of the sec- ondary axial ray approaching the weak surface in both cases. N 2 is fixed by the refracted section, in the lens, in both cases. N 2 is the same distance from the lens surface in both instances; but the other two points differ be- 72 A SYSTEM OF MATURE MEDICINE cause of. the relative location of the two surfaces in each lens. The sur- face of the -)- lens is 4 mm. nearer the center of curvature of the -f- than the positive surface ; while the + surface of the lens is 4 mm. farther from the center of curvature of the than the negative surface. In meniscus lenses focal distances are measured from the optical center and N'. Rays entering a + l en s parallel with the axis on the + side would find their focal point on the opposite side of the lens at a fixed distance from N'; and rays entering from the side, parallel with the axis, would find their focal point on the opposite side at a fixed distance from O. Rays entering a -- lens from the side, parallel with the axis, would find their negative focal point at a fixed distance on the same side of the lens, measured from N' ; and rays entering from the -f- side, parallel with the axis, would find their negative focal point at a fixed distance on the same side of the lens, measured from O. It is important to get this straight in order to make calculations for principal and conjugate foci. N 2 is a dead point in both lenses. As mistakes are made easily in drawing, it is necessary to have formulae with which to test the work ; and, having them, better drawings are possible. To locate the optical centers and nodal points of meniscus lenses we employ the following: The lens thickness may be 4, 6 or any other figure. These calculations are to illustrate principles. For -f- lenses : (1). The short radius is R' and the long radius is R 2 . R' x lens thickness ,. , r r -7^5 TJTT T , n . -7-T-j = distance from 4- surface to O. (R z R ) x I + -J lens thickness Thus, in Fig. 61 R' is 20 and R 2 is 40 points. Lens 4 points thick. 20X4 = 80 01/ r r (40-20) 20x1.50 =30 + 2 = 32 =2/2 mm ' ft ~ m + SUrfjK * tO ' Or, (2). Using short and long focal distances of single curves, S' is the strong surface and S 2 is the weak one. F' is the short focal distance and F 2 is the long focal distance of each surface. S'F' x lens thickness , , r r , c2r , 2 c ,T-, 2 x i . -r^-: = distance from + surface to O. (S F 2 S F 2 ) + lens thickness In Fig. 61 S'F' is 40; S'F 2 is 60; S 2 F' is 80; S 2 F 2 is 120. Lens thick 4. 40 x 4 = 160 , . r - ; =2-vo mm. from + surface to O. (120 60) 60 + 4 = 64 To locate the nodal points for surfaces of + lenses : R 2 x lens thickness . . r r -\T/ -T TTT: T ! n = distance from surface to N . (R a R ) x I + lens thickness 40x4 = 160 = (40 20) 20 x 1.50 = 30 + 2 = 32 ~ r\ S'F' x lens thickness , f f -\T/ Or, . C2T72 , = distance from surface to N . (S F S F 2 ) + lens thickness 80x4 = 320 p -j AT/ = o mm. from side to N . (120 60) 60 + 4 = 64 To locate the nodal points for -4- surfaces of + lenses : R' x lens thickness = digtance frQm surface ^ ^ K. K. Thus, _^_ ~~_ = 4 mm. from -4- surface of -f- l ens to ^ 2 . For lenses: (1). _^_R^en S thickness = distance from _ surfac to O . (R 2 R ) x I ^ lens thickness REFRACTION, ETC., BY MENISCUS LENSES 73 Thus, in Fig. 62 : 20x4 = 80 =2 % mm. from surface to O. (40 20) 20 x 1.50) = 30 2 = 28 Or, (2). Using short and long focal distances of single curves: S'F' x lens thickness j- , f < /-\ (S'P-S'F)- lens thickness = = dlStanCC fr m " - = 36/7 f _ urface t (120 60) 60 To locate the nodal points for -(- surfaces of lenses : -7=5 x e nst ic ness = Distance f rom _j_ surface to N'. (R R ) x I i lens thickness ^Q x 4 __ -J^gQ (40 20) 20 x 1.50 = 30 2 = 28 ~~ >/7 r .C.2T--2 o>T'2\ i ,. < == distance irom -4- suriace to JN . (S F S r ) lens thickness 80x4 = 320 = 5% mm. from -f- side to N'. (120 60) 60 4 = 56 .To locate the nodal points for surfaces of -- lenses: R'x lens thickness _ distance from _ surface to NS> ' 1\. K. Thus, 20 x * = 8 = 4 mm - from the surface of N 2 . 40 20 = 20 To locate the principal focal distances for -f meniscus lenses: Fig. 64 is a reproduction of the + exhibit in 63, for convenience. It is a reduced drawing and should be made on mm. scale by students : As single curved surfaces, both have their long focal distances on the right side, because the short focal distance is on the outside of -f- and on the inside of curvatures and the long focal distances are on the inside of -f- and on the outside of curvatures. The ray R', parallel with the axis, strikes the -f- surface and is refracted in the direction 60, because : RXl-^ExI = F 2 , and 20X1.50 = .30-:- .50 = 60. The lens is 4 points thick, hence the point 60 is only 56 points from the surface; and to finish the calculation and locate F' on the right, we make a positive proposition of the distance 56 and follow the rule for single curved surfaces : = Cf ' Thus : - 3 "" 70 mm - positive, hence, side to F'. Adding to this the 5 points from the surface to N', gives the principal focal distance ^5. [] h-.H ig The ray R 2 , parallel with the axis, strikes the surface and is refracted so that it passes through the lens as if it came from a point 120 mm. distant, because, 40x1.50 = 60-f- .50 = 120. Adding the thickness of the lens gives 124 points to the + surface, and, following the rule, as before : 74 A SYSTEM OF MATURE MEDICINE 124x40=4,960 -,/ ... , T?, T- J = 77% mm. positive, hence, -f- side to F'. De- 1 w j uU o4 ducting 2% points for the distance from the -+- surface to O, leaves 75. Note that the principal focal distance of this lens is 75 points, which represents 13.33% units. The ordinary method of calculating such lenses is to disregard the thickness and assume that putting two piano-curved lenses together, one with a radius of 20, and a principal focal distance of 40, or -4- 25.00 units, and the other with a radius of 40, a principal focal distance of 80, 12.50, would give -f 12.50 with a principal focal distance of 80. But the drawing and calculation show this is not true. The student may take any thickness of lens and make calculations for exercise, when he will find facts which will enhance his respect- for optics and for those who spend their lives digging out the truths, and will certainly be better able to do good work by insisting that prescription houses respect him and his orders. To locate the principal focal distances for - - meniscus lenses : R 1 LJ Fig. 65 is a reproduction of the exhibit in 63, for convenience. It is also a reduced drawing to be made to mm. scale by students : As single curved surfaces, both have their long focal distances on the left side, for the same reasons given for the -f- having them on the right. In meniscus lenses they are always on the side of strongest curve. The ray R', parallel with the axis, strikes the - - surface and is re- fracted in the direction negatively 60, because that is the long focal dis- tance of the surface. Adding the thickness of lens, 4, makes 64 from the pV)int 60 to the -j- surface of the lens. . x _~^_ ~ 91% negative F from -(- side. Deducting the dis- tance from the -f- surface to N', 5%, leaves 85% negative focal distance from N'. The ray R 2 , parallel with the axis on the -f- side, strikes the surface and is refracted so that it passes through the lens toward the second principal focal point of that surface, 120. Deducting the thickness of the lens leaves 116 as the first conjugate focal distance, negative, from which to find the final focal distance : 1 !? <; X 4 ft r_ tt = 836 /7 negative distance from side. Adding the lit) DU 5u distance from the surface to O, 2%, gives 85% from O. Note that for the -f- lens the focal distance from the nodal point N' is measured on the opposite side of the lens ; and from the optical center on the same side of the lens. Also note that for the lens the focal distance from N' is measured on the same side of the lens; and from the optical center on the opposite side of the lens. Fig. 66, mm. scale, shows how to find a radius which will complete a R' approaches the -4- surface parallel with the axis, and is refracted to- real -4- 12.50 lens, meniscus form : REFRACTION, ETC., BY MENISCUS LENSES 75 -J?,3 ward point 60, as in Fig. 64. With the second surface 4 points from the first, the distance is reduced to 56. This distance, divided by the index of refraction, 1.50, gives the radius of curvature for the surface. 56-^1.50 = 371/3 radius,-f- .50 = 74% F / ,+37 1 / 3 = 112 F 2 , and, remembering it is a negative proposition, we have: Locating the optical center we have: 20 x 4 = 80 to O. (37% 20) 17% x 1.50 = 26 -f 2 = 28 4 from -[- surface Locating the nodal points we have : 37% x 4 = 149% (37% 20) 17% x 1.50 = 26 + 2 = 28 face to N'. 20x4 = 80 ,/ - 5 l / 3 from sur- The distance F 2 , added to the distance from the surface to N', 5%, gives 80 points, the principal focal dis- tance from N' If the radius is other than twice as great as the +, the procedure for finding the radius is to get the ratio of unit power, then multiply the distance found (as 56, above) by that, then divide by the index and multiply by the excess index to get the radius. Thus, the power of the + above is twice that of the side, hence : 56x2 = 112-T--1.50 = 74 2 / 3 x .50 = 37%. R 2 , approaching the surface parallel with the axis, is refracted as if it came from the point F, 112 points from the surface, because that is F 2 , negative, of that surface. Adding the distance from the to the + sur- face, 4, gives 116 points as the first conjugate focal dis- tance from the -f- surface, and following the rule : 116x40 = 4,640 _ Q0fi/ ^ -nv ^ + he , sur f ace> 116 hO = 56 Deducting the distance to the optical center from the -f- surface, 2%, leaves 80 points as the principal focal " distance, from the optical center, on the + side and from N'on the side. Note that the secondary axial ray, S', is directed toward the optical center and crosses the axis at that point; and, after refraction by both surfaces of the lens it passes away to S 2 as if it came from N'. This is the reason for measuring the respective focal distances from O and N'. The space between those two points is dead. The dashed lines along the secondary axial ray are to show the courses of the sections before and after refrac- tion, and the very slight change suffered by these rays. 76 A SYSTEM OF MATURE A!EDICINE Note also that to get the principal focal distance, 80, corresponding to 12.50 units of power, the radius of the surface had to be shortened to 37% from 40, shown in Fig. 61. Now let us see what will happen when we want to make a 12.50 meniscus : Fig. 67, reduced, to be made to mm. scale by students, shows such a lens; starting with a radius of 20, ray R' approaching the concave surface parallel with the axis is refracted and passes the lens as if it came from 60 mm. from that surface, because it is F 2 . Adding the thickness of the lens, 4, makes 64 as Cf for the convex surface. This negative focal distance, divided by the index, 1.50, gives the radius necessary for the + surface to get the desired focal distance : 64-^1.50 = 42% mm. the radius of the -f- curve. 42%x.50 = 85% F',+42% = 128 F 2 . To locate the optical center: 20 x 4 = 80 (42% 20) 22% x 1.50 34 2 = 32 To locate the nodal points: = 2% to O from surface. - 5l /3 to H' from the + side. 20 x 4 = 80 42 % _ 20 = 22% The ray R' approaching the -}- surface from 64 points suffers positive refraction but the effect is negative because the first principal focal distance of a surface with a radius of 42% is 85%, therefore : = 85% from the + surface to F. Deducting the distance from the + surface to N', 5% leaves F 80 from N'. Ray R 2 entering the lens at the -f- surface is first directed toward a point 128 mm. positive, on the opposite side of the lens. Deducting the thickness of the lens, 4, leaves 124 from the surface, and : 124x40 = 4,960 -,, r r tr i -j = 77% mm. from surface to F on -f- side. OU i I*i4 t)4 Adding the distance from the surface to O, 2%, makes F 80 on the -f- side from O. Note that the radius of the -f- surface had to be lengthened to get the actual focal distance of a 12.50. The standard meniscus lens is always - - 1.25 or -j- 1.25 on its weak side, hence, when combined with a strong -f- or curve on the opposite surface the optical center is very close to the strong side; almost the same as a piano-curved lens. There is a form of meniscus lens, which is widely advertised by manu- facturers and their allies, for commercial purposes, because there is great profit in its sale, which is actually injurious to wearers, on account of chro- REFRACTION, ETC., BY MENISCUS LENSES 77 matic aberration, while it scarcely approximates the trial lenses used in fitting, which are bi-convex and bi-concave. These lenses are made on minimum "base" curves of 6.00 units; thus a -f- 2.00 would be ground - - 6.00 on one surface and -f- 8.00 on the other. The short radius, with index 1.50 is 62.5 and the long one is 83%. Fig. 68, mm. scale, shows such a lens, made to actual measures, accord- ing to usage : Locating the optical center: Lens thickness, 3. 62.5x3 = 187.5 K - 62%) 20.83% X 1.50 = 31% + 1% = 83^x3 = 250 -j Slde - 62%) 20.8 3 y 3 x 1.50 = 3iy 4 + ^ = 32% 62.5x3 = 187.5 83% 62% = 20.83% A ray approaching the -f- side, parallel with the axis, would be refracted at the first surface and go toward a point on the axis 187.5 distant. As the second surface is 3 points nearer the distance is 184.5 : 184.5 x 166% = 30,750 Acn K { f TT -A 184.5 -250 = 65^ = 469 ' 5 fl " m ~ SUrfaCC tO F n that Slde ' A ray approaching the side, parallel with the axis, would be refracted at the first surface and go to the second as if it came from 250 points away on the axis. Adding 3 for lens thickness we have : 253x125 = 31,625 - <00 o r r T- -j - , Q - , _ ' = 482.8 from -j- surface to I 1 on that side. *&Oo lo * .O OO.D Adding to F on the right the distance from surface to N', 469.5+7.6=477.1== principal focal distance from N'. Deduction from F on the left the distance from -f- surface to O, 482.85.7 = 477.1 = principal focal distance from O. But note that a + 2.00 should have a principal focal distance of 500 mm., and this lens misses that focal distance 23.4 mm. Such a lens, if made bi-convex, would have its optical center and both nodal points within a space of 1.5 millimeters, all inside the lens. The way to treat the claims of exploiters of such lenses is to place them alongside lenses of the same unit number from the trial set. No argument will be needed to show which is the best lens for all purposes. The boasts of manufacturers go glimmering like fog before sunlight. Their published charts showing the "values" of the meniscus lenses in forming pictures is shown to be a deliberate humbug. Then it should be remembered that no lens forms the picture at the retina; lenses merely add to or subtract from 78 A SYSTEM or MATURE MEDICINE the power of the refracting system of the eye by altering the courses of rays as they enter. Fig. 69, reduced, to be made to mm. scale by students, illustrates con- jugate focal distances by a -f- meniscus lens. The first thing to do is to locate the optical center and the near nodal point; then the principal focal distances; assuming a lens thickness of 2 points: " distance from side to O. n (R R) h i. lens thickness 10 x 2 = 20 f t (20 10') 10 x 1.50 = 15 + 1 = 16 Same rule except using R 2 for first multiplication locates N'. ^* * a B r 40 . g , . 7T=2.5 mm. from surface to N'. (20 10) 10 x 1.50 15 + 1 = 16 The principal focal distance is located as follows : A ray approaching parallel with the axis from the - - side would pass the lens as if it came from a point 60 from the surface. Adding lens thick- ness makes the distance to the -f- surface 62. ^^=38.75 from -f- surface to principal focal point. 62 30 32 Deducting the distance from -f- surface to O, 1.25, leaves 37.5 as P F. Next, the first conjugate focal distance, F, is 90 from the optical center and 91.25 from the + surface. Using the rule for single curves: Cf ' x OFF rt 2 Cf'-NBF =Cf 2 , wehave: 91-35x30 = 2737.5^ 38.42 or F' toward which the ray will be directed. 91.25 20 71.25 To find the final point after second refraction : The distance F', less thickness of lens, 2, is 36.42 points. This is a surface but the above for- mula works by using the distance 36.42 as if the surface were +, and F' will be on the same side, because the lens as a whole is -}-. 36.42 x 40 = 1456.8 - DU C1 o , , '= 61.78 from the concave surface. 61.78+2.5 to N' gives 64.28 as Cf 2 of lens. Having the principal focal distance and the first conjugate focal distance of the lens as a whole : Multiply the first conjugate focal distance, from the optical center by the principal focal distance and divide by the difference between them: 90x37.5=3,375 . , r ,,, ^ ~, 2 = 64.28 points from N' to Cf 2 . yu 37.5 = 52.5 Proving the work by using the Base-Line method and starting from F 2 we have the ray F 2 B to the concave surface, which the Base-Line parallels; then, drawing the perpendicular from C 2 to C 3 and measuring from B to C 3 , 34 mm., then measuring from C 3 to A the same distance, we locate the point to measure from. Multiplying 34 by 1.50 and dividing by .50, gives 102 mm. on the Base-Line from A to the point to which the ray will be directed REFRACTION, ETC., BY MENISCUS LENSES 79 while passing the lens ; and, continuing that direction backward from the lens, it strikes the axis at F', where the refracted ray from F was directed by the first surface. Now, making another Base-Line, parallel with the course of the ray while passing the lens, erecting a perpendicular from C' to the convex surface where the refracted ray strikes it, the distance on that perpendicular is 10 points, which, divided by the excess index, .50, gives 20 points from the surface along the Base-Line to C 4 where the emergent ray crosses on its way to F. Thus the first procedure is proved. Reflection from the + surfaces of meniscus lenses is always negative and from the -- surfaces is always positive, as has been illustrated in the chapter on single curved surfaces; therefore it need not be repeated here. This is the wife of a Minnesota doctor who not only had a divergent squint but had been given up to die from tuberculosis. She had not done any work for a long time. After six months' neurological treatment, she has been doing the housework for her husband and six children over a year. These Eyes Straightened Instantly. A SYSTEM OF MATURE MEDICINE Here is a little girl who was not only cross-eyed, but her disposition was twisted so that she was a charge. These pictures were taken two weeks apart, hence it was four weeks from the first to the last and her moth- er reported there was as much change in her disposition as appears in her face. An operation might have straight- ened the eyes, temporarily, but it could not have touched the disposition, be- cause glasses are not nearly all of the neurologist's armamentarium. Ophthalmology isn't any old thing some cheap imitators choose to call ophthalmology. CHAPTER IX. Refraction and Aberration of Tri-Curved and Other Lenses. In architecture there is a half-round hoop ornament for pillars which is called a "tore." A segment of such an ornament would be regularly curved; but it would be neither spherical nor cylindrical. It would have curve in every meridian; but there would be two extreme ones, at right angles, one with maximum and the other with minimum power; between these two, as in cylinders, there are pairs, one on either side of one of the principal meridians, which are of equal power. Lenses made with such surfaces are called "toric" on account of the form. It is a law that all regu- lar, non-spherical curved surfaces have their two principal meridians at right angles, hence, when oculists and opticians prescribe cross-cylinders with axes not at right angles they prove they know nothing of optical laws and that they have misfitted the eyes the glasses are ordered for. Fig. 70 shows a toric surface. The curves II H and I indicate the meridians of minimum and maximum power; the intermediate meridians in- creasing gradually from H to I as described in Chapter IV, Fig. 42, with the difference that in this instance the curve H is substituted for the flat surface in the other cut. There the meridian had no power; here all merid- ians have power, but at H there is the least. Suppose this surface has a principal focal distance for the horizontal meridian of 16 cm., the diameter of the globe represented by that curve, and the other meridian has a principal focal distance of 7 cm., which is the diameter of that circle; then all other meridians, in pairs, would refract rays to planes at right angles with the axis at points between 7 and 16 cm. be- yond the lens, forming a caustic, as was shown in illustrating spherical A SYSTEM OF MATURE MEDICINE aberration in Chapter III, but with the difference that in this instance there is a cylindrical effect which destroys the image-forming capacity, because there is no place in the caustic where there is any approach to a common focus as there is in spherical aberration. Placing a slotted disc over a lens made in this form with the slot on one of the principal meridians will permit an image to be formed, because all light is shut off from the non-spherical meridians ; but the slot at any other meridian will give no such results, be- cause, if the slot is at the 45th meridian, for example, all light passing above the central line will be refracted toward the vertical meridian and slightly toward the horizontal, exhibiting a vertical mark on a screen. If the same experiment be tried on a cylindrical -f- lens the mark will be as long as the distance across the lens, because there would be no upward or down- ward refraction as there is in the compound or toric surface. Toric lenses are rarely needed, but many are prescribed, and they are fraudulently advertised as of special value, when, as a matter of fact they are actually harmful for the reason that they are made in the meniscus form, one surface of + lenses being deeply concave making it necessary to make the other surface more convex, as was shown in the chapter on meniscus lenses. Suppose a lens is needed with -f- 8.00 power in the vertical meridian and -f- 9.00 in the horizontal. This would need a very strong sphere and a comparatively weak cylinder. Made ordinary sphere-cylinder style it would be a -f- 8.00 sphere combined with a -J-LOO cylinder, axis 90, which would give the power of the sphere at the 90th meridian and the power of both sphere and cylinder at the 180th meridian, with the gradual increase of cylindrical power in all other meridians, which Nature takes Care of if we look after the principal ones. But, this would give -|- 8.00 curve on one sur- face and + 1.00 on the other, making an awkward appearing lens. To obviate this and reduce the aberration to its minimum, we would make the spherical surface of one-half of the power called for by the horizontal merid- ian, then make the toric surface to finish the demands of both meridians. Fig. 71, mm. scale, sectional views of the horizontal and vertical merid- ians of the same lens made bi-convex and meniscus sphero-toric. The cross at the right gives the power required for each of the two meridians. The four sections H H and V V show how that power is furnished by the two lenses ; the power units and the radius of each surface in centimeters are recorded at each surface of the drawings. The chromatic aberration of torics makes them positively injurious to the eyes and the high curves in- REFRACTION, ETC., BY TRI-CURVED LENSES 83 crease the reflection until the lenses are as conspicuous as automobile head- lights. It is a paradox that opticians who recommend torics are the same chaps who advise the invisible bifocals; but they care nothing for consistency if they can secure the extra profits of both. The bifocal mentioned is not only very expensive but it has the chro- matic aberration fault exaggerated to the limit. Even the optical houses devoted to prescription filling have announced that they "will not be re- sponsible for chromatic aberration in the fused bifocals." These optical houses differentiate between the deep meniscus and bi- convex and bi-concave lenses by calling them, respectively, "toric" and "flat" lenses. The indexes of the glass used for fused bifocals is said to be 1.523 and 1.60 ; therefore, in filling a prescription for -f- 2.00 add + 2.00 for near work, the distance lens to be "flat," there would be a power of -f- 1.00 on each sur- face, and with index 1.523, the radii of these surfaces would be 52.3 cm., because the principal focal distance of each is 100 cm., which, multiplied by the excess index, .523, gives the radius 52.3. Then, as one of the surfaces is used for the insert, the portion devoted to near work must have an in- creased power by reason of the higher index. Radius 52.3-H- .60 = 87% cm., or 1.147 diopters. The other surface of the main lens furnishes 1.00 diopter power so the total is 2.147. Subtracting this from 4.00, the total reading power wanted, leaves 1.853 to be added by the "buried" curve; and 100, divided by 1.853 gives 54.5 cm. as the principal focal distance of that dioptric power. This 54.5, multiplied by the difference between the two indexes, .077, gives 4.196 cm. as the radius of the buried curve. But they are often made "toric" or deep meniscus, with a 6.00 or even a 9.00 base curve. The lens just described made on a 6.00 base would have a -f- 8.00 curve on the opposite side to get the desired -4- 2.00. Then, if the insert be fused on the -- side the radius of curvature of the buried curve would be found as follows : The 6.00 has a principal focal distance of 16% cm., which, multiplied by the excess index, .523, gives a radius of 8.716 cm. This, divided by the excess index of the addition, .60, gives a principal focal distance of 14.526 cm., or 6.8842 diopters, an increase of the - surface, hence to regain the lost .8842 and add -4- 2.00 the buried curve must supply 2.8842 diopters, which, with a focus of 34.524 multiplied by the difference between the two indexes, .077, gives a radius of 2.658 cm. for the buried curve. See C 3 A, Fig. 72. If the addition is to be made in the -4- side of the lens we have the radius, 6.537, divided by .60 gives 10.895 cm., or 9.178 diopters, leaving only .822 D. to make the full -f 10.00 against the - - 6.00 for near work. This .822 divided into 100 gives a principal focus of 121.65, which, multiplied by the difference between the two indexes, .077, gives 9.36 cm. as the radius of the buried curve. See B, Fig. 72. Then compare either A or B, Fig. 72, with C, at the right, where the respective radii of the two sides are recorded together with the radius of the cement scale on the outside. This is practically as "invisible" as the fused bifocal, has no chromatic aberration and in case the addition for read- ing needs changing the main lens does not have to be thrown away as is 84 A SYSTEM OF MATURE MEDICINE the case with the fused. This scale should be made oval 16 mm. long, 14 mm. high and 1 mm. up from the edge of the main lens. I/ 1 c' R 6.7/6 p B In order to make the foregoing more emphatic the following drawings are given to show that when lenses are made ten times as strong as those illustrated in Fig. 72, the curves on the bi-coavex are only a little greater than for the + 2.00 "torics." ff.7' 6 Fig. 73 shows what the curves would be for the strong (20.00D) "toric," as the radii are millimeters instead of centimeters. As a matter of fact a toric of the strength indicated could not be made, for the figure shows the actual size of the lens. C' Fig. 74 shows the bi-convex as it would appear in comparison with the "toric." It could be made and used ; and it demonstrates that with the thin scales added for near work bifocals may be made for the strongest lenses people ever need without any serious aberration. Fig. 75 shows the ordinary meniscus lens as a possibility and that while it would be superior to the "toric" it has some of the fault complained of hence it does not compare at all favorably with the bi-convex. Compare the radii of the main surfaces and of the segments and it is easy to see that the longer they are the better, if the nearest possible flat sur- REFRACTION, ETC., BY TRI-CURVED LENSES 85 faces are desirable ; and we have shown why such is the case. Another form of bifocal is called the one-piece. It is a meniscus of the worst variety, that is with a 6.00 base curve, spherical, large enough for two lenses, with a weaker -- curve ground in the center, so that a -f- sur- face ground on the other side gives both distant and near power. See "A", Fig. 76, which is prepared for an addition of + 3.00. If -+- 8.00 be ground on the other surface the result will be + 2.00 for distance and + 5.00 for near work. c A IF C B * B, Fig. 76 shows how a -- lens may be made without the thick edges of the ordinary - - lens. It is first ground bi-convex, then the curves ground in those surfaces. This is on the same principle as the "lenticular" lens, D, in the cut. The opposite form of "lenticular" lens is shown in C. These are only employed when unusually strong lenses are required. Fig. 76, E shows how lenses are constructed when it is necessary to reduce chromatic and spherical aberration to the minimum. The middle piece is bi-convex, of twice the focal power wanted, and it is made from "crown" glass ; Then the two outside pieces, made from "flint" glass and each of one-fourth the power of the middle piece, aggregating one-half its power, are so placed that they neutralize half of the original refracting power, and, with their double index of dispersion, neutralize all of its dispersive power. This is called an aplanatic lens. If made from two pieces, the flint being all on one side, it would be an achromatic lens, that is, the color aberration would be rectified but there would still be spherical aberration. There are other freak forms of lenses, exploited with great claims of superiority, such as "greater field of vision," "making clearer images," etc., all of which is what is popularly called "bunk", because spectacle lenses are not used for taking pictures, but for changing the course of rays entering the eyes. None but ignorant people are fooled by such advertisements. But, as Barnum said "there's a fool born every minute." The manufacturers of freaks are getting the money and the people not only give it up but suffer for it. 86 A SYSTEM OF MATURE MEDICINE Other forms of lenses of several curvatures are the "split" and "per- fection" bifocals, the "one-piece" bifocal, made for near work, with a place ground out of the top for distant vision, and other devices of minor im- portance unworthy of mention, because most of them are no longer used. This cross-eye case responded to rational methods in a few days. CHAPTER X. Neutralization of Lenses, Prescription Writing, Transposition and Analysis. The neutralization of lenses is a simple thing yet it requires considerable care to do it correctly even when well informed in principles. The first es- sential is to be familiar with the following facts : 1. Prisms refract rays toward their base lines, consequently objects observed through a prism will appear displaced toward the apex. Rotating a prism around the visual line, that is a line from the eye to the object, will move the apparent or virtual object with its apex, thus it may be carried clear around a circle; but it will not distort the object. Holding a prism base-apex line vertical, for example, and moving it right and left or up and down while viewing the object will have no apparent effect. 2. Spherical lenses, -j- or -t-, when rotated as described above, exhibit no effects, because the same strength of prism is always present; but mov- ing them across the visual line or back and forth along it, there will always be motion of the virtual object. It will move in the direction opposite to your movement, if the lens be -)- and in the same direction you move the lens if it be . 3. Cylindrical lenses -f- or -- distort objects when rotated around the line; a cross, for example, will take the form of an "x" when the lenses are in certain positions where the axis of the cylinder and the meridian at right angles therewith are not in positions corresponding to the actual positions of the lines ; the -f- will distort against your movement and the - - with it. Axial meridians being considered. The opposite meridians will reverse these effects. 4. Compound lenses may be composed of spheres and prisms, or of spheres and cylinders, or of spheres, cylinders and prisms, when they will all exhibit their peculiarities and we must be able to distinguish not only the presence of each but the nature as to -)- and spheres and cylinders. Prisms are neutralized by using other prisms, bases reversed, until one is found which stops all rotary motion ; or, a very good way is to use a vertical or horizontal line, placing the base-apex line of the prism at right angles, noting the displacement of the line while passing the prism and put on such other prism as will neutralize the displacement. Thus, if the prism to be neutralized is base down the neutralizing prism will be base up; and the known power of the neutralizing prism tells the power of the neutralized one; but do not forget the base is reversed. Spherical lenses are neutralized by sphericals of the opposite nature. That is, -f- are neutralized by - - and vice versa. In doing this work the 88 A SYSTEM OF MATURE MEDICINE lens to be neutralized should be held as far from the observer as possible, even to arm's length as the work is about complete, or the exact power will not be found. Then the matter of getting the axial lines of the two lenses so that they are one line is important as the slightest deviation will cause a lens to cause object motion. I presume more mistakes are made in this particular than in any other in process of the work of neutralization. Compound lenses, if sphero-cylindrical, must be held so that the two principal meridians correspond to the two lines of the cross ; then it is proper to neutralize the meridian of least motion first, with a sphere and finish the other one with a cylinder. Thus, if -f 1-00 neutralizes the horizontal meridian but there is still motion to the vertical meridian, we know more -(- will be required to neutralize it, but a -f- cylinder, axis horizontal, must be used because the spherical lens which has fixed that meridian, must not be disturbed. If -f- 1.00 cylinder, axis horizontal, finishes .the neutralization, we have -j- 1.00 sphere -f- 1.00 cylinder axis horizontal, hence the lens neu- tralized must be a 1.00 sphere 1.00 cylinder axis the same. Remember that the axis is always the same but the signs of power reverse in neutraliza- tion ; but in transposition the axis always changes 90 degrees if the sign of cylindrical power reverses. If a compound lens combines a prism neutralize the prism with prisms, the sphere with spheres and the cylinder with cylinders. If either sphere or cylinder is present alone neutralize it with another of its class but of opposite sign. tUO . ^6 $0 Fig. 77 is a protractor ,0 for locating the axes of cylindrical curvatures. Sometimes they are in oblique positions on lenses and in order to neutralize them the lens has to be held obliquely on a vertical-horizontal cross placed at some distance from the opera- tor, and, when the axis is located, if an ink mark is placed on the edge of the lens and the lens laid on the protractor it will give the meridian. But here is another particular point: If the axis is oblique in any position except 45 and 135 the protractor only gives the merid- ian on which the axis will be before the eye if the up side of the lens is from the eye ; if the down side be placed from the eye the axis will be far from correct. For example : a lens marked and laid on the protractor shows the axis to be 30 ; turn the lens over and the axis will be found at 150. Or if at 60 with one side up it will be at 120 with other side up. If the same side is NEUTRALIZATION, PRESCRIPTION WRITING, ETC. 89 up it makes no difference if the lens is turned end for end. If the axes are vertical or horizontal it makes no difference which side is up or which end is toward the nose. These are the two principal meridians and the two sec- ondary meridians of lenses and also of the eyes. Prescription writing is of great importance, because, in practice, if one is not entirely familiar with it as a physical and physiological proposition it is a serious handicap. The physiological aspect will be considered in an- other chapter. Remember a spherical lens has equal focal power in all meridians while a cylindrical lens has focal power only on lines at right angles with the axial line, hence, referring to meridians, only on the meridian at right angles with the axis. It has curves in all meridians except the axial one; and they refract rays to point on the axial line, but no two rays refracted by the same oblique meridian curve will hit that line at the same place. Fig. 78 shows a cylindrical lens; lines 1 and 2 are oblique meridians crossing the center; rays approaching the surface parallel with the axis will be refracted along the lines R R R R from the points O O O O. A prescription for a compound lens is written correctly when the signs are alike, as -j- 1.00 -{-.75 axis 90 ; or, 1.00 2.00 axis 180. Also when the signs differ and the cylinder is at least twice as strong as the sphere, as -+- 1.00 2.00 axis 180. If written -f 2.00 1.00 axis 180 it would be wrong because the lens is -f- in all meridians, as analysis will show. The fact that no cylinder has any power on its axis leaves the full power of the + 2.00 at the 180th. meridian and at the opposite one, the 90th, where the cylinder exerts all of its power it still leaves a -(- 1.00 effect; therefore the prescription should be written -f- 1.00 -)- 1.00 axis 90 to be in its simplest form and such a prescription would cost ten cents less than when written the other way. Fig. 79, shows the locations of the principal focal points in Emmetropia, Hypermetropia and Myopia with reference to the retina, or posterior pole; Note that in Em. the retina is at the principal focal point; in Hy. it is in front of the principal focal point, and in My. it is behind the principal focal point. The "punctum remotum" or far point of an eye is the point with which the posterior pole is in conjugate focus when the eye is in its "static" condition, that is in its natural state, without any use of the accommodation or facilities for adjusting the crystalline lens. The old teachings are that the far point of an emmetropic eye is at infinity ; that of a hypermetropic eye is beyond infinity and that of a myopic eye is nearer than infinity. 90 A SYSTEM OF MATURE MEDICINE As a matter of fact only the myopic eye has a far point, because it is the only one which will take rays which start from the posterior pole and bring them to a point on the axis outside of the eye, while the emmetropic eye sends them away parallel with the axis and the hypermetropic eye sends them divergent from the axis. See Fig. 80. Transposition of prescriptions not only puts them in proper form and often saves money, but it is abso- lutely necessary in the analysis of conditions, not merely static, but dynamic. The latter will be treated later; the static is given here in -order to present the proposition in its simplest form. Fig. 81 shows the position of the focal points with reference to the retinal plane, R, when rays approach the cornea, C, parallel with the axis. The first three are simple conditions in which the refraction is spherical hence all meridians are represented in one angle. The last five are compound conditions in which the angles show the two principal meridians. When we take a prescription which reads -f~ ! " " .50 axis 180, for example, we first draw a line in the direction indicated by the axis and Fig. 77. Thus, 180 is a horizontal line. On it write the sign and power of the sphere; then draw another line at right angles with the first, forming a cross, and on NEUTRALIZATION, PRESCRIPTION WRITING, ETC: 91 it write the power of the -f- sphere less the power of the cylinder, in this instance, -f- .50. This shows the effect of the combination in the two prin- cipal meridians. Then draw a vertical line, like R, Fig. 81, and diagram the condition as indicated by the cross. See Fig. 82. Fig. 82. '0V To rewrite the prescription, begin with a sphere of the kind and strength indicated on the diagram for the meridian of least defect; in this instance it is -f- .50, because the points are behind the retina ; this sphere shortens the focus of both meridians, bringing the 90 to the line and the 180 nearer, see A, Fig. 83. Then give a cylinder of the kind and power indicated, -f- .50 Fig. 83. in this instance, placing the axis in front of the meridian already corrected by the sphere ; this corrects the deficiency and both meridians focus on the same plane; the result is that the combination of lens and eye gives a focus as if the eye were truly emmetropic as shown in Fig. 79. The prescription now reads, -J-.50+.50 axis 90. See B, Fig. 83. If a prescription reads -f- 1.00 1.75 axis 45 we put it on the cross and diagram as Fig. 84. /.PtS Fig. 84. + 1.06 Now, correcting the meridian of least defect will require a sphere .75, which will drive the 135th meridian back to the retina, A, Fig. 85, but it will also push the other meridian back .75 so a -f- 1.75 cylinder will be re- quired to pull it forward to the line, and the prescription will read .75 -f- 1.75 axis 135, B, Fig. 85. The nature of the error will be found by re- ferring to Fig. 81 which shows it to be mixed astigmatism. s-nS Fig. 85. It may be seen here that if a slotted disc is placed before the eye at 92 A SYSTEM OF MATURE MEDICINE the 135th meridian there is nothing but simple myopia to deal with and if placed before the 45th meridian there is nothing but simple hyperopia to measure; hence in fitting glasses in some cases we proceed in that manner to get approximately the correction for each meridian, then working from the cross we diagram the eye, put on the combination indicated and work on from that until we secure desired results. Sometimes a prescription reads like this : -\- 1.00 T*.00 axis 180. When it is put on the cross we have -f- 1.00 at the 180th meridian and nothing at the 90th, because the cylinder neutralizes the sphere in that meridian ; and on the diagram the 90th meridian would have its point at the line "R" while the other would be behind it 1.00. It is easy to see that only a -f- 1.00 axis 90, a simple cylinder, would be needed, and the saving in cost is 50 per cent. Following is the law for transposing and analyzing compound prescrip- tions as evolved from the foregoing: First meridian, Power of sphere; . To put on cross Second meridian, Power of sphere and cylinder; To rewrite the Prescription I 3 4 Diagram condition of eye as indicated by cross; 5 Correct meridian of least defect with sphere; 6 Allow for its effect on the opposite meridian; 7 Finish with cylinder, axis on corrected meridian. No one who knows his business will ever find a cross-cylinder combina- tion, that is two cylinders, with axes not at right angles to each other. There are isolated cases were cross-cylinders might be used but they would never have their axes in any position except at right angles, because of the law that toric surfaces always have their two principal meridians in that relation. For example, if one meridian of an eye called for 5.00 and the opposite one required -f- 5.00, a sphere cylindrical prescription would read 5.00 -f- 10.00 axis on the meridian fixed by the sphere ; a 5.00 axis, say 180, com- bined with a -f 5.00 axis 90, would do the work a little better than the sphero- cylindrical combination; but the expense would be greater. To transpose a prescription written arbitrarily thus, -f- 2.00 axis 45 1.50 axis 180, the best and surest way is to neutralize it, when it will be found that the prin- cipal meridians are not as indicated by the axis given, but are at the 60th and 150th meridians, that a + 1.00 2.50 axis 60 will neutralize it, hence it will be duplicated with a 1.00-f2.50 axis 60. CHAPTER XI. Physical Construction of the Eyes, Standard and Defective. Nature never fixed any units of measure, such as a mile, quart, inch, "morals," or anything else. But there are Natural standards in all things, if we can find them. In our search we are always hampered by "accepted authorities," who are nearly always wrong, and by fanatical, dogmatic, ignorant hordes who revel in their own superstitions. Taking for a standard an ideally proportioned eye, based on carefully made tests of indexes of refraction of the media and the actual measure- ments of corneal and lenticular curves, there is a length on the antero- posterior axis of % inches, or 22.86 millimeters. The posterior curve of the crystalline lens, with a radius of 6 mm., has its apex on the axis 15.66 mm. from the posterior pole of the eye; the anterior curve of the lens, with a radius of 10 mm., has its apex on the axis 3.6 mm. farther from the posterior pole or 19.26 mm. from it. This leaves 3.6 more as the distance from the anterior curve to the cornea. Therefore, to construct a sectional eye we must proceed from the posterior pole with a ray divergent from the axis and figure the effect of each surface of the lens separately ; then, finally, we find the required radius of curvature of the cornea to render rays parallel with the axis as they leave the eye. The procedure is that employed in single curved surfaces : To make it all clear to the student we must take the indexes of the various mediums and establish the first and second principal focal points of the two surfaces of the lens. Compared with air the index of the cornea and aqueous humor, considered as one, is 1.3365 ; that of the vitreous humor is the same; that of the crystalline lens is 1.4371. Compared with the aqueous and vitreous humors the index of the crystalline humor is 1.4371 -7-1.3365 = 1.0752. J, I. 7f2 \ f ' =. Fig. 86 shows the posterior surface of the crystalline lens, radius 6 mm., with F' 79.787234 mm., or 12.532 diopters, and F 2 85.787234 mm., or 11.645 diopters. The first is found by dividing the radius, 6, by the excess index, .0752, and the second is found by adding the radius to the first prin- cipal focal distance. 94 A SYSTEM OF MATURE MEDICINE Fig. 87 shows the anterior surface of the lens, radius *10 mm., with F' 132.9787 mm., or 7.52 diopters, and F 2 142.9787 mm., or 6.994 diopters. Fig. 88 shows the lens as a whole, index 1.0752, principal focus the same on either side, 49.87, or 20.052 diopters. This is found in two ways : First, by adding the dioptric power of the two surfaces, calculated separate- ly, using the first principal focal distance of each, thus, 7.524-12.532 = 20.052 ; 1 "1 10 A 1 f\ second, by adding the two radii as common fractions, thus, + -f = - 6 10 60 60 60 which, reduced, is the denominator being the equivalent of the two O. i O radii for use as a piano-curved lens, and this figure, divided by the excess index, .0752, gives the principal focal distance, 49.87, which, divided into 1,000, gives the dioptric value, 20.052 if the thickness of the lens is dis- regarded; but this cannot be ignored for the reasons to follow: The optical center of the lens, O. 6 is found by adding the two radii and cutting out the top figure, leaving of the thickness of the lens (3.6 mm.) from the weak side toward the strong one as the location of O, r 2.25 mm. from the weak side, which is the anterior surface. The nodal points of the crystalline lens are located as for bi-convex lenses, viz : The optical center distance, from either surface, multiplied by F' of that surface and divided by F 2 , less the distance from the optical center to the surface, gives the distance from that surface to its nodal point. There- fore : 2.25x132.9787 _ 299.202075 = g 12fin tQ N for 142.9787 2.25 140.7287 1.35x79.787234 107.7127659 t ^~ -x , 85.787234- 1.35 84.437234 Thus, the anterior nodal point is .1240 mm. in front of O and the posterior one is .0723 mm. behind O. Therefore, in view of the foregoing explanation, we must find the exact power of the lens according to the rules given in Chapter VI. for bi-convex lenses: 10x1.0752 = 10.752 ^ 9 , . , -^ , ,. ,, - = 142.9787 = F 2 of anterior surface. Deducting the .07D<& thickness of the lens, we have: 142.97873.6 = 139.3787, and, following the rule: 139.3787 x 79.787234 = 11120.64095151 139.3787 + 85.787234 = 225.165934 = 49.3886. PHYSICAL CONSTRUCTION OF THE EYES 95 Adding the distance from the posterior surface of the lens to the posterior nodal point, we have : 49.3886+1.2776 = 50.6662 mm. principal focal distance. 1000-^50.6662 = 19.737 diopters of power. Fig. 89, made on a scale of % centimeter representing 1 millimeter, shows a ray started from F' toward the lens and divergent from the axis is refracted at the posterior surface and passes through the lens as if it came from F 2 , because, figuring according to the laws of refraction by single curved surfaces, we have :^|^ S _orif^= 2 O.D4 negative focus. In other words: the first conjugate focal distance, 15.66, multiplied by the opposite principal focal distance of the surface, 85.787234, equals 1343.428084; this divided by the difference between the first conjugate focal distance, 15.66 and the principal focus on the same side of the surface, 79.787234, which is 64.127234, gives 20.94 which is a negative focus because the starting point is inside of the principal focal distance on that side. Adding to 20.94 the distance from the posterior to the anterior surface of the lens, 3.6, we have 24.54 mm. as the first conjugate focal distance , 24.54x132.9787 3264.54729 o -, K(t . , of the anterior surface, and : + 24 . 84 _ 142 . 9787 or 11?-4893 = 27.56 negative focus. Or, the first conjugate focal distance, multiplied by the opposite prin- cipal focal distance and divided by the difference between the first conjugate focal distance and the principal focal distance on the same side, gives the second conjugate focal distance, which is negative for the same reason the other was, hence the ray passes away from the anterior surface of the lens as if it came from F 3 . Now, adding the distance from the anterior of the lens to the cornea, 3.6 mm., we have 27.56+3.6 = 31.16 mm., which is to be regarded as the second principal focal distance of the cornea. To find the first principal focal dis- tance we apply the law of single curved surfaces that the principal focal distances are to each other as the indexes of refraction of the two mediums. Therefore, 31.16-j-l.3365 = 23.318, (43.224D), the first principal focal dis- tance; and this, multiplied by the excess index, .3365, gives 7.84 as the radius of curvature of the cornea necessary to take the ray away parallel with the axis. Fig. 90, scale % cm. equals 1 mm., shows the sectional eye complete. At 1 is the center of curvature of the cornea, radius 7.84; at 2 is the center of curvature of the anterior surface of the lens, radius 10 ; at 3 is the center of curvature of the posterior surface of the lens, radius 6 ; 4 is the center of curvature of the globe, which, beginning at the points of junction of the curves of the cornea and posterior surface of the lens, requires a radius of 10.8. The scale on which this cut is made is the same as for Fig. 89. 9G A SYSTEM OF MATURE MEDICINE It has been shown in Fig. 88 how the optical center of the lens is located. It was also shown in previous chapters how optical centers change with changes of arrangement of surfaces. Here we have a,new proposition: One single curved surface, the cornea, and one double curved lens, the crystal- line, for the same general reason that a cylindrical surface combined with a spherical one makes two optical centers the eye combination, even without astigmatism, has two optical centers ; but there is the exception in this in- stance that the optical center of the lens is put out of action. To locate the optical center of the combination we take the distance of the optical center of the lens from the cornea, 5.85 and that of the optical center of the cornea, 7.84 and regarding them as we did the two radii of the lens we add them, 5-85 7.84 t cutting out the top figure we have the fraction : . which is that 13.69 . portion of the distance from the optical center of the lens to the optical center of the cornea at which is located the optical center of the combina- tion. The difference between those two points is 7.84 5.85 = 1.99, and 784 of that is 1.138, which added 'to the distance of the optical center of the 1369 lens, 5.85, makes 6.988 mm. from the cornea to the optical center of the combination, marked O in the cut. O 2 is the optical center of the lens alone. A ray starting from the posterior pole of the eye, divergent, would be refracted as described under Fig. 89, and, finally, the corneal refraction would render it parallel with the axis on leaving the dioptric system. Starting the ray from the inside, parallel with the axis, we would have first the second principal focal power of the posterior surface of the lens : 6 X 1.0752 _._ 6.4512 oe ivoivoo/i v r Q752 or OT52 = 85.787234 positive focus. In other words : the radius multiplied by the index and divided by the excess index gives the second principal focal distance, from the posterior surface of lens. Now, deducting the thickness of the lens, 3.6, leaves 82.187234 from the anterior surface of the lens to the point found. Then we proceed : 82.187234x142.9787 , 11751.0238 ... , f = ^.13o positive focus. -8M87834+ 132.9787 50.7914 Or, the focus found multiplied by the opposite principal focus of the. PHYSICAL CONSTRUCTION OF THE EYES 97 anterior surface of the lens and divided by the difference between the focus found and the principal focus on the same side gives the second focus, which is positive. Deducting the distance from the anterior of the lens to the cornea, leaves 19.535 as the focal distance to be considered. Proceeding as before, except using the principal focal distances of the cornea, we have : 19.535x31.16 608.7106 ... , , ,. . or . = 16.09 positive focal distance. 19.535 + 23.318 3.783 Or, the focal distance found multiplied by the opposite principal focal distance and divided by the difference between the focus found and the principal focal distance on the same side gives the second focal distance, which is positive. Adding to the focal distance from the cornea the distance from the cornea to the optical center of the combination we have 16.09 + 6.988 = 23.078 as the principal focal distance of the eye outside. Deducting from the total length of the eye the distance from the cornea to the optical center we have 22.86 6.988 = 15.872 as the principal focal distance of the eye inside. The nodal points of the eye are three in number and they are located from the optical center bv calculation as follows: The distance from the cornea to the optical center is 6.988 mm. The first principal focal distance of the cornea is 23.18 mm., the second principal focal distance is 30.98 mm. The first principal focal distance of the anterior surface of the lens is 132.4787 ; the second principal focal distance is 142.4787. The first principal focal distance of the posterior surface of lens is 79.787234; the second principal focal distance is 85.787234. Following the rule given in Chapter VI for finding nodal points we have for the anterior point : The distance of cornea from optical center. 6.988x23.18 = 161.98184 30.98-6.988 = 23.992 ' The distance from the anterior of lens to optical center is 3.388, and to c. j .1 -jji A 3.388x132.4787 448.8378 . f find the middle point : , _ =3.215 mm. from anterior of lens to N. The distance from the posterior of lens to optical center is .212, and to r- , , , . A .212 x 79.787234 = 16.91489 , find the posterior point: 85 . 787234 _^ 12 = ^5^3 -.197 mm. from posterior of lens to N. This places the anterior point .238 mm. in front of O ; the middle point .173 mm. in front of O ; and the posterior point .015 mm. behind O. The principal focal distance from the optical center to the posterior pole of the eye is 15.872 mm., or 63.00 diopters. The perfectly normal eye is not only constructed according to the proportions described, but the crystal- line lens is built in layers, arranged as shown in "E", Fig. 76, except that the lens comprises many layers, doubtless for the same purpose, that of pre- venting aberration. An eye may be larger or smaller than the one described but so long as it retains the proportions given it will be normal, that is the retina will be at the principal focal distance of the dioptric system. This is called "Emmetropia" meaning literally "in-measure-eye." Departures from normal proportions are all included in the term "Ametropia, the nega- 98 A SYSTEM OF MATURE MEDICINE tive "A" being substituted for the positive "Em." The most common defects are in the forms of the cornea and globe. If the radius of the cornea is too long or that of the globe too short the retina will be in front of the principal focal point of the system and the condition is called Hypermetropia, mean- ing literally, "beyond-measure-eye," because a ray started from the axis at the posterior pole of such an eye, would be divergent after final refraction and there would be no focal point outside of the eye ; therefore the Hyper- metropic eye is a eye. If the radius of the cornea is too short or that of the globe too long, the retina will be behind the principal focal point of the system, when the condition is called "Myopia" meaning literally, "Muscle- eye," so called because people so affected have the habit of closing the lids to form a narrow slot, which improves vision ; but this habit must not be re- garded as evidence of myopia, because hyperopes with astigmatism often do the same thing. If both only knew it a card with a pin-hole in it would be better because it would only let axial rays pass and vision would be fine. Quite frequently eyes are found with toric corneas, like the surface of the lens shown in Fig. 70, so that rays passing it are refracted as by such a lens, thus preventing a perfect focus on the retina, which is the seat of the Astigmatism, as it is called, because the word means "without a point." This does not interfere with vision very much unless there is a diopter or more difference between the two principal meridians, because the image- forming power of such a system of 63 diopters, coupled with a delicate ner- vous system is not easily thwaited in that particular; but there are other features which make it important to be corrected to the point of comfort. There are five regular subdivisions of Astigmatism. If one principal meridian is emmetropic and the other one is hypermetropic, it is called Simple Hypermetropic Astigmatism. As a matter of fact it is compound, because all meridians, excepting the normal one, are hypermetropic on a gradually increasing scale to the one of maximum error. This is only a technical point, however, for the reason that the law: All regular, non-spherical, curved surfaces have their two principal meridians at right angles, takes care of it so that a simple cylindrical lens will correct all defective meridians provided one meridian is normal. If one principal meridian is emmetropic and the opposite one is myopic, it is called Simple Myopic Astigmatism. If all meridians are hypermetropic, but there are two principal ones of mini- mum and maximum defect, it is called Compound Hypermetropic Astigma- tism. If all meridians are myopic, but there are two principal ones, of minimum and maximum defect, it is called Compound Myopic Astigmatism. If one principal meridian is myopic and the opposite one is hypermetropic, it is called Mixed Astigmatism. The first two are corrected with simple cylindrical lenses ; the other three by sphero-cylindrical lenses. As a reminder of the information and skill required to find and correct errors of refraction attention is called to the fact that with a perfect dioptric system of 63 units of power the principal focal distance is 15.872 mm. from the optical center; while with one diopter of hyperopia the focal distance is 16.129 or only .257 mm. farther; and one diopter of myopia shortens the focus to 15.625 a change of .247 mm. The latter impairs vision consider- ably for distant objects, and the former causes great disturbances phy- PHYSICAL CONSTRUCTION OF THE EYES 99 siologically, proving the keen sensibility of the nervous system more than any other one thing physical. An approximate way to construct the sectional, eye, similar to Fig. 90, is to start from the axis in the same manner, but figure in diopters : The distance from the posterior pole to the posterior surface of the lens is 15.66 mm., which calls for 63.857 diopters of which the second principal focal power of the posterior surface of the lens pays 11.645, leaving 52.212 needed; this represents a negative focal distance of 19.1526 mm., to which must be added the distance from the posterior to the anterior surface of the lens, making 22.7526 mm., calling for 43.951 diopters, of which the first principal focal power of the anterior surface of the lens pays 7.52, leaving 36.431 un- paid and a negative focal distance of 27.449 mm., to which must be added the distance from the anterior of the lens to the cornea, 3.6 mm., making a total 31.049 mm., which represents the second principal focal distance of the cornea; and this divided by the index, 1.3365, then multiplied by the excess index, .3365, gives the radius necessary for the cornea, 7.81739973. Or, starting parallel with the axis inside the eye, we have first, the second principal focal power of the posterior of the lens, 11.645 diopters, with a focal distance of 85.787234 mm.; subtracting the thickness of the lens leaves 82.187234 mm., or 12.16 diopters; adding the first principal focal power of the anterior surface of lens, 7.52, gives a total power of 19.68 diopters, with a focal distance of 50.813 mm. ; subtracting the distance from anterior of lens to cornea, 3.6 gives 47.213 mm., or 21.18 diopters ; adding the first principal focal power of the cornea, 43.224, we have 64.40 diopters with 15.52 mm. focus. Adding 6.988, the distance from cornea to optical center, we have 22.508 mm. as the outside principal focal distance, measured from the optical center. Dividing by the principal focal distance inside the eye 15.872, gives 1.417 as the index of the eye taken as a homogeneous body. Of course these figures are not so accurate as those made from the single surface method of calculation, but they are given for practice work. "Authorities" have stated that the line of vision does not correspond to the optical axis of the eye, that it is really a secondary axis. Then they make "very schematic" drawings to illustrate the angles alpha and gamma, at- tempting to show that the first named is formed by the "line of vision" and the "major axis of the corneal ellipsoid"; the second by the "line of fixation'' and the optical axis; then they state that the fovea centralis is .2 mm. out- side of the axis at the posterior pole of the eye. They forgot, or did not know that while liars will figure, figures will not lie. We have seen that the principal focal distance of the standard eye is 15.872 mm. We have seen, in physical optics, that an object is to its image, in size, as the conjugate focal distances are to each other. The average pupillary distance is 58 mm.; therefore taking the usual working distance 6000 mm. and dividing it by 15.872, the principal focal distance, we have a relation of 378 between an object at 6000 mm. and its image on the retina. One half of the pupillary distance is 29 hence that is to be taken as the size of the object and 29-f-378 = .0767 mm. from the optical axis at the posterior pole, or considerably less than half the distance claimed by them, making it a matter of such minor 100 A SYSTEM OF MATURE MEDICINE importance that it would not be worth noting were it true, which it is not, being merely an assertion impossible of proof ;' and it shall be shown that the accommodation necessary for 6000 mm. is accompanied by a proportionate amount of convergence to bring the optical axes, which are the real visual axes, into position to see singly. If the crystalline lens were absent, as it is after 'cataract operation, or as it is sometimes naturally aphakic, the index necessary for normal vision would have to be 1.52198, because the antero-posterior length of the eye 22.86 mm. would be F 2 of the cornea, with its radius of 7.84, which, deducted from F 2 leaves 15.02 as F 1 , and : F 2 -^ 1 == I. Thus 22.86-^-15.02 = 1.52198, index. Emmetropia Hyperopia Myopia CHAPTER XII. Physics of Retinascopy and Why it Will Not Work Physiologically. There are a lot of mystery-lovers in the world and among them is found the Retinascope fiend. There are two classes of him : The first class com- prises oculists who declare it cannot be used successfully until after the eyes have been doped with atropine (deadly night-shade), and they are notoriously unsuccessful in fitting glasses, treating eyes and in operating, all because they know so little about physical laws and the anatomy and physiology of the eyes that it is not worth mentioning. We are able to prove this even on those who have written "authoritative" text-books we prove it by their books, compared with the truth. The other class is com- posed of a lot of self-styled "optometrists," who have spent a lot of time and money seeking legislation recognizing them as professional people when they should have spent it securing some little knowledge of the work they profess to do. They are smarter ( !) than the oculists, because they do not need atropine, they can do the job without; one subdivision of this class even pretends to do it "dynamically," which wins for them the optical dunce-cap easily. Fig. 91 shows an emmctropic eye being flooded with light .from the lamp, L by way of the plane mirror, M, and being directed toward the point O, behind the eye, it forms a spot on the posterior field of the eye. Returning, from the point F dotted lines 1 and 2 show the extreme edges of the beam, one-half being on each side of the axial line P c O. The point c where that line crosses the Optic Axis is the optical center, on which the whole matter hinges, physically. With the mirror in position M the entire pupil is illuminated and the red reflex from the retina is seen. Tilting the mirror 102 A SYSTEM OF MATURE MEDICINE to position 1 will throw the illuminated field at the retina downward, and, as the beam represented by the dotted lines is balanced on the center c, throwing the point F down will tilt the beam upward at the outer end, so that all of that half of the beam coming from the side of the axis, P c O, marked 1 will be moved upward and the observer at P only receives that from the side marked 2, which also moves upward, hence he will note an apparent shadow pass over the pupil from above downward. As he tilts the mirror back toward position M the whole pupil will be illuminated again ; but as he tilts it on toward position 2, thus raising the illuminated field of the retina, the outer end of the returning beam drops down and he only receives light from the side of the beam marked 1, and the shadow will appear to pass from below upward. In other words, the shadow moves with the movement of the mirror. This is always true when a plane mirror is used, so long as the two halves of the returning beam remain on the same side of the line P c O that they were when they left the eye. This is always the case in Emmetropia, Hyperopia and in Myopia when the far point is farther away than the mirror. Fig. 92 is a hyperopic eye and the dotted lines 1 and 2 show how the beam spreads as it leaves such eyes. The explanation of the emmetropic figure fits this one equally well so far as the movement of the shadow is concerned. Were there nothing but physical conditions to deal with there would be a difference in the result of the procedure of applying lenses. As the rays leaving the emmetropic eye are parallel with the axis P c O, -f- lenses would be placed in front of the eye until the out-coming rays were focused at the observer; if he is at a distance of one-half meter and the eye is emmetropic, a -|- 2.00 will do the work and the shadow will disappear, because the rays from the entire pupillary field are brought to the peep- hole P in the mirror. If the eye is hyperopic 1.00 D, it would require -\- 3.00 to do the same work, because the rays are divergent as they leave the eye, instead of parallel. Therefore the working distance must be considered in all cases. Working at one meter the emmetropic eye would require only -)- 1.00 and the hyperopic would require -(- 2.00. It follows that after stopping the shadow in any eye with lenses there is too much -)- in the combination of eye and lens by the equivalent of the working distance. Working at one-half meter and finding no shadow would mean the eye is myopic 2.00 D. Working at that distance and finding that -f- lenses less than 2.00 D. stop the shadow would mean that the eye is myopic the diff- PHYSICS OF RETINASCOPY 103 erence between the power of -\- 2.00 and the amount of the + lens found; thus, if a + 1-00 stops the shadow the operator being in conjugate focus with the retina must have -\- 2.00 over the normal condition and if the lens only furnished -(- 1.00 the eye must be doing the rest. Fig. 93 shows an eye which is myopic more than the working distance, as is indicated by the focal point of the dotted lines 1 and 2 between it and the mirror. In this instance, tilting the mirror to position 1, throwing the illuminated field of the retina down, will tilt the out-coming beam up, as before, but with a different result, because the upper half of the beam be- comes the lower half at x and the lower half becomes the upper; therefore, as the beam tilts up the lower part, coming from the upper half of the pupil, is all that is seen by the operator, so the shadow appears to come from below, or against the motion of the mirror. Tilting the mirror back toward the first position M the entire pupil is illuminated again, but as it is moved toward position 2, the luminous field of the retina being raised the outer end of the beam is lowered, and at the operator's eye the upper end of the beam is from the lower half of the eye, and being all he receives, the shadow comes from above downward, the darkness being due to the simple fact that the light from that part of the eye does not pass to the operator's eye. In such a case lenses would be used until the shadow stopped because the point x is moved to the operator's position ; but even then the eye is still undercorrected the equivalent of the working distance for the same reason that the -f cases are overcorrected that amount. Such glasses require the addition of -- lenses equivalent to the working distance to finish the case. Fig. 94 illustrates the concave mirror employed in emmetropia. The light, L' gives off rays a c and b d, which strike the mirror and are reflected 104 A SYSTEM OF MATURE MEDICINE to form L 2 , which becomes the source of the illumination of the eye, and a second image would be formed at O if the light could get there. With the mirror in position M the pupil is entirely illuminated for the observer because the beam is coming out between dotted lines 1 and 2 from F, at the retina. On tilting the mirror to position 1 the luminous point L 2 is lowered ; this raises the illuminated field of the retina, and, the out-coming beam being hinged on the optical center c its outer end drops so the observer only receives light from the upper part of the pupil, the shadow coming up to meet the downward movement of the mirror. Reversing the mirror movement the shadow backs off until the pupil is all red, the tilting the mirror toward position 2, raises L 2 , thus lowering the illuminated field of the retina and the outcoming beam is tilted upward so the operator only receives light from the lower half of the eye and the shadow comes down to meet the upward movement of the mirror. l! - '-I Fig 95 is a hyperopic eye, showing the out-coming beam spreading as it leaves the eye. The explanation of the emmetropic eye fits -this one so far as the movement of the shadow is concerned ; the only difference is in the amount of power in the lens required to stop the movement of the shadow. Working at one-half meter the emmetrope would require a -|- 2.00 and the hyperope enough more to correct the hyperopia. Then, from the amount found in both instances 2.00 D. would be deducted for the work- ing distance, leaving nothing for the emmetrope and whatever there is more than -f- 2.00 for the hyperope. If the lens thus found is less than -f- 2.00, working distance one-half meter, the difference between the lens found stopping the shadow and -f- 2.00 is myopia. Fig. 96 shows an eye which is more myopic than the working distance, PHYSICS OF RETINASCOPY 105 as is indicated by the crossing of the out-coming rays 1 and 2 at x. In this instance, tilting the mirror to position 1 lowers L 2 , raising the illuminated field of the retina, which lowers the outer end of the out-coming beam, and as the two halves have changed positions, lowering that end of the beam gives the observer rays from the lower half of the eye only and the shadow goes down with the mirror. Reversing to position 2 raises L 2 , lowers the illuminated field of the retina, which raises the outer end of the beam and the observer receives light from the lower half only, which is the upper half at the eye, hence the shadow goes up with the mirror movement. Of course - - lenses must be used to stop the shadow by moving the point x to the operator's position, and they must be increased an amount equivalent to the working distance to give the full correction. It makes no difference what the working distance is, the principles set forth work all the time. With the plane mirror the shadow goes with the operator's movement in hyperopia, emmetropia and myopia of less than the working distance; and it moves against the mirror movement in myopia greater than the working distance ; that is when the far point is between the operator and the patient. For convenience in putting on lenses, the half meter distance would be the most natural. With the concave mirror the movements of the shadow are the reverse of those with the plane one. As a physical proposition this is as easy as neutralizing lenses; but few can do that exactly; particularly those who pretend to be able to fit patients with the mirror, either hand or machine. As a physiological matter it is an impossibility, both theoretically arid practically, with or without atropine ; because, to paralyze the nerves of accommodation so they could not work at least a little under the irritation produced by flooding the eye with light, would result in the death of the patient in many cases; then the operator could never tell when he had total paralysis and repeated tests of patients believed to be in a state of total cycloplegia proved the contrary. Without atropine, even presbyopes have their accommodation stimulated by the extraordinary light from the mirror and the retinascopic "correc- tion" is always far from the total amount of hyperopia and always entirely too much in myopia. In all of our experience of about a quarter of a cen- tury, we have never found a case "fitted" with a retinascope to have any- thing approaching the real correction as found by subjective methods and proved after a long period of time for the nervous system to become ad- justed to the new situation. Nor have we met, in all this time, a retina- scopic "professor" who could demonstrate the theory of the proposition correctly. "Eminent" writers on the subject have exposed themselves by discussing the relative values of the plane and concave mirrors, the sizes of the peep-holes, the working distances and even the diameters of the mir- rors. Nothing could be more absurd, as the explanation of the principles will prove readily. Retinascopists are the people who talk about "latent myopia" and ar- gue that if a patient sees just as well with a -j- 1.00 fitted with a retina- scope as he does with a -f- 2.50 fitted by a rational method it proves it is as good a correction. " They do not even suspect the existence of a method of 106 A SYSTEM OF MATURE MEDICINE proving work. They are so utterly ignorant they do not want to learn. So mote it be. I see their finish. What I have said about the retinascope as a practical instrument for physiological purposes also applies to the ophthalmometer, and all other instruments and machines with which it is pretended errors of refraction can be measured accurately. The ophthalmoscope is a valuable auxiliary in practice; but not as a means of fitting glasses. The perimeter has limited uses in finding the field of vision ; but it is not worth its cost to the practitioner, because it offers no means of enlarging the field. When optical houses advertise "instruments of precision" with which to measure eye de- fects they are making false statements, which are forbidden by law. Retinascope Ophthalmometer CHAPTER XIII. Exercises Involving the Principles of Physical Optics. 1. Q. What is light? A. Natural light is a substance as is indicated by its composition repre- sented in the spectral colors. In addition to its luminous properties it exhibits effects upon animal and vegetable life and upon mental conditions. Artificial light is like other artificial propositions a weak imitation of the Natural, lacking many of its essential qualities. 2. Q. What is refraction of light? A. Refraction of light is the deviation in its course a ray suffers when it passes, obliquely, from one transparent medium into another of different optical density. 3. Q. What are the factors involved in accomplishing refraction? A. The factors involved in the refraction of light are the chemical com- position of the transparent mediums and the mechanical construction of those mediums ; or, in other words, the optical density of the mediums and the obliquity of the approaching ray. 4. Q. What is meant by "optical density"? A. Optical density differs from mere compactness in referring to the re- sistance offered by transparent mediums to the passage of light through them. 5. Q. What is an index of refraction? A. An index of refraction is the expres3ion in figures of thp relative op- tical density of any medium compared with an established standard. Or, index of refraction is the quotient obtained by dividing the size of the angle of incidence by the size of the angle of refraction when a ray of light passes obliquely from a vacuum into the substance whose index is wanted, both these angles being measured on straight lines set square with the perpendicular to the surface and measured at equal distances, along the ray of light, from the point of refraction. Index of refraction is also the quotient obtained by dividing the speed of light in a vacuum by the speed of light in the substance whose index is wanted. 6. Q. What is the index of refraction of air? A. Air, compared with a vacuum, has the index 1.000294. 7. Q. What is air, chemically? A. Air is a mixture of nitrogen and oxygen in proportions of 4 N to 1 O. 108 A SYSTEM OF MATURE MEDICINE 8. Q. What is glass, chemically? A. Glass belongs to the salts family, chemically. 9. Q. What is water, chemically? A. Water is hydrogen mon-oxide, a compound. 10. Q. Knowing the indexes of two different mediums how would a new index be established between them? A. By dividing one into the other. It is best to divide the smaller in- dex into the greater, but it works either way. 11. Q. When a ray is refracted what else happens to it? A. It suffers reflection, dispersion, absorption to some extent. 12. Q. What are the four angles exhibited in connection with refraction? A. Angles of incidence, reflection, refraction, deviation. 13. Q. What is meant by positive and negative refraction? A. As a ray enters a dense medium it is broken out of its course toward a perpendicular to the surface at that point ; as it passes from that into a rarer medium it is broken from such a perpendicular. The first is positive and the second negative refraction. 14. Q. What is their cause? A. The cause of the first is the angle of approach and the chemical at- traction of the denser medium. The cause of the second is the angle of approach and the loss of the chemical attraction of the dense medium. 15. Q. What are the four methods of making drawings illustrating refrac- tion by plane, parallel surfaces? A. First, the perpendicular-parallel method ; second, the circle method ; third, the chord-arc method ; fourth, the base-line method. 16. Q. What is the advantage of the base-line method over the others? A. It works equally well with any index of refraction. 17. Q. Why is the angle of deviation greater as a ray leaves the denser medium than when entering it? A. Because the angle of refraction on entering the denser medium is only one-third, or thereabouts, less than the angle of incidence, while on leaving the dense medium the angle of emergence is one-half, or thereabouts, greater than the angle of incidence to the second surface. 18. Q. Of what value are physical principles beyond their physical uses? A. If we apply them in the development of our reasoning faculties their value is inestimable. 19. Q. What is the difference between vertical and perpendicular? A. Vertical is always straight, up and down ; perpendicular may be hori- zontal, oblique or vertical, because it means at right angles with an- other position. 20. O. What is a parallel? A. It is represented by two lines always at the same distance from each other, as the mark = Relating to Prisms: 21. Q. What is a prism? A. A prism is a transparent wedge. EXERCISES IN PHYSICAL OPTICS 109 22. Q. What is the law of prisms? A. There are two of them : First, rays passing a prism are always broken toward the base line, hence objects seen through prisms are always apparently moved toward the apexes. Second, the angle of deviation of a ray by a prism is always in the same ratio to the angle of construction of the prism that the excess index of the glass used is to the index of air, or 1.00. 23. Q. What is the angle of construction of a prism? A. It is the angle formed between the two sides and the base. 24. Q. What is the angle of deviation of a ray? A. It is the angle formed by the course of the incident ray and the back- ward prolongation of the emergent ray. 25. Q. How may the angle of deviation be found without making a drawing? A. By multiplying the base line of the prism by the excess index of re- fraction we get the base line of the angle of deviation, measured the same distance from its apex that the base of the prism is from its apex. 26. Q. How do we locate the position of the apex of the angle of deviation? A. Take the index of air as the numerator of a fraction the denominator of which is the index of the denser medium ; that fractional part of the distance through the prism, on the line of incidence, will be the apex of the angle of deviation. 27. Q. Suppose you have the angle of deviation wanted how would you find the angle of construction of the prism? A. Divide the base of the angle of deviation by the excess index of the dense medium. 28. Q. But if you are not given the base line, what then? A. If the angle be given in degrees, minutes and seconds, reduce to the smallest division, divide, and restore to degrees, minutes and seconds. 29. Q. How are prisms numbered? A. In degrees, centrads and ordinary units. The latter is the best be- cause it is numbered similarly to lenses. A prism of such an angle of construction that it will take a ray approaching parallel with the base-line and one centimeter from it, and break it to the base line at one meter, is denominated a 1.00 prism; and any prism that takes such a ray and breaks it to the base line at any other distance bears the same relation to 1.00 that the distance bears to one meter, or 100 centimeters. Thus, if a prism breaks such a ray to a point one-half meter distant it would be a 2.00; or if one should break it to a point on the base line at two meters it would be a .50. Or, if the approach- ing parallel ray is nearer or farther from the base line than one cen- timeter, the distance from the prism at which the ray strikes the base line is first divided into 100 to get the power it would have if the ray was one centimeter from the base line on entering, then the result must be multiplied by the distance from the base line the approaching ray actually is. Thus if a certain prism breaks a ray, approaching parallel with the base line, to a point 20 centimeters from the plane of refraction, that distance, divided into 100, would 110 A SYSTEM OF MATURE MEDICINE give 5.00 as the power represented ; but if the ray struck the prism two centimeters from the base line it would mean 5.00 X 2 = 10.00 prism. Or, if it was only half a centimeter from the base line on entering, it would mean 5.00 X -50 = 2.50 prism. 30. Q. What is the difference between the above described method and the two others? A. Practically no difference up to about 10 degrees, which is the highest power ever needed. The reason for the difference then is that in the higher powers the base line and the arc of the base of the prism are perceptibly different in length and degrees are measured by the arc. The same difference is found between the centrad, or median line measure and the others. Relating to Single Curved Surfaces: 31. Q. What is presented by a single curved surface? A. A multitude of angles presented to rays approaching parallel with the axis, but at different distances from it. 32. Q. What is the object of this sort of surface? A. It is for the purpose of securing a combination of prism effects which will bring a bundle of approaching rays to a common point beyond that surface. 33. Q. Does it do this? A. Not absolutely. There is always, in spherical curves, a constant shortening of the meeting points of pairs of rays at equal distances from the axis as they are farther from it, so that there is no point common to all. This is called spherical aberration, and the distance along the axis from the shortest focal point to the longest one is called the caustic. In lenses such as are used for the eyes, how- ever, only small portions are used at once on account of the size of the pupil of the eye, therefore the aberration does not interfere with vision. 34. Q. Where is the optical center of a single curved surface? A. It is the center of curvature. 35. Q. What is its radius? A. The distance from the optical center to the surface. 36. Q. How many principal focal distances has a single curved surface? A. Two; measured from the surface the first principal focal distance is in the rare medium and it bears the same relation to the second principal focal distance, in the dense medium, that the index of the rare medium bears to the index of the dense. 37. 'Q. How are these points located? A. The radius, divided by the excess index of the dense medium gives the distance to the first principal focal point ; and this distance, plus the radial distance is the second principal focal distance. Or, the radius, multiplied by the index of the dense medium and the product divided by the excess index of the dense medium, gives the second principal focal distance. 38. Q. Why are they not the same length? A. Because there is greater deviation of rays approaching the surface EXERCISES IN PHYSICAL OPTICS 111 parallel with the axis in the dense medium than there is of those ap- proaching the surface parallel with the axis in the rare medium. 39. Q. Being given the two principal focal distances what is the proceeding to find the radius of curvature? A. The difference between them would be the radius of curvature. 40. O. What are conjugate focuses? A. They are respectively the points from which rays diverge and toward which they are converged by the refracting surface. The word "con- jugate" means "yoked together." The point where an object is located is the first conjugate focal point and the point where the image is formed is the second conjugate focal point. 41. Q. An object placed 100 cm. outside of a single, convex curved surface, having an index of 1.50 and a radius of 20 cm., at what distance in- side the dense- medium will the image be formed? A. The first thing to do is to find the outside principal focal distance : Radius, 20, divided by the excess index, .50, gives 40 cm. as the principal focal distance. Then 100X60-^(100 40)60 = 100, the second conjugate focal distance. 42. Q. Being given two conjugate focal distances and the radius of curva- ture of a single curved surface, what is the proceeding to find the index of refraction? A u (C'+R) x C 1 A. Formula : ,~ ~ ' 7 ^- = Index. (,C K.) x (^ 43. Q. Index 1.52; radius 20 cm.; find first principal focal distance? A. Radius, 20, divided by excess index, .52, gives 38.4615 as the first principal focal distance. 44. Q. Index 1.53; radius, 30 cm.; find second principal focal distance? A. Radius, 30, multiplied by the index, 1.53 and divided by the excess index, .53, gives 86.6 as the second principal focal distance. 45. Q. Index 1.53; first principal focal distance 9 cm.; what is the radius? A. Given focal distance, 9, multiplied by the excess index, .53 gives 4.77. cm. as the radius. 46. Q. Radius 24 cm.; first principal focal distance 52; what is the index? A. Radius, 24, divided by the first principal focal distance, 52, gives .4615 as the excess index, to which add 1.00, making 1.4615, index. 47. Q. Radius, 20 cm.; second principal focal distance 60 cm.; find index? A. Second principal focal distance, less the radius gives 40 cm. as the first principal focal distance, which, divided into the second princi- pal focal distance, gives the index, 1.50. 48. Q. Index 1.53; radius, 15 cm.; image 80 cm.; what is object distance? A. Radius, 15, divided by the excess index, .53, gives the first principal focal distance, 28.3 ; adding the radius gives the second principal fo- cal distance; then, if the image is in the dense medium, multiply its distance, 80, by the first principal focal distance, 28.3, which gives 226.4, and divide by the difference between the image distance, 80 and the principal focal distance on that side, 43.3, which is 36.7, and the result is 61.68, the object distance from the surface. 49. Q. Index 1.54; second principal focal distance, 24; find first principal focus? 112 A SYSTEM OF MATURE MEDICINE A. The given distance, 24, divided by the index, 1.54, gives 15.5844 as the first principal focal distance. 50. Q. Under what circumstances do the first and second principal focal dis- tances reverse their relationship? A. When they are measured from the optical center instead of the surface? 51. Q. What are the relative sizes of objects and images formed by re- fraction through a single curved surface? A. They are in the same ratio the two conjugate focal distances are to each other, measured from the optical center. 52. Q. The dense medium presents a concave surface with a radius of 20 cm. ; Rays approaching parallel with the axis will be focused by re- flection where? A. At one-half the radius of curvature, or 10 cm. 53. Q. An object is placed 100 cm. from above surface; where will its image be formed? A. The first conjugate focal distance, 100, multiplied by the principal focal distance, 10, and divided by the difference between them, 90, gives 11% cm. as the second conjugate focal distance by reflection. 54. Q. Radius, 10 cm. ; index, 1.52 ; what is the prism value 4 mm. from the axis? A. Radius, 10 cm., divided by the excess index, .52, gives 19.269 as the first principal focal distance, which, divided into 100, the standard of measure, gives 5.184 units if the rays are parallel in the dense medium 1 cm. from the axis, or base line; but as this one is only 4 mm. or %o cm. from the axis it follows that it is only four-tenths of 5.184 units prism effect, or 5. 184X-4 = 2.0736 units prism power. If the rays approach parallel with the axis in the rare medium the prism effect is weaker. To find the units divide the last figure by the index, 1.52, which gives 1.3642 as the prism units effect on rays en- tering the denser medium at that distance from the axis. Relating to Lenses: 55. Q. Principal focal distance 50 cm. ; index 1.52 ; what are the radii of four lenses, made plano-convex, bi-convex, standard meniscus and "toric," (deep meniscus), with base curve 6.00? A. For plano-convex, the principal focal distance, 50 cm., multiplied by the excess index, .52, gives the radius, 26. For a bi-convex of the same power, the radius of each surface will be double that for the plano-convex. For the standard meniscus, which has a base curve of - - 1.25, hence a principal focal distance of 80 cm., the radius of the surface would be 80X-52 = 41.6 cm. ; the other side would have to be 1.25 stronger than the plano-convex, which is -4- 2.00 in order to make up for the negative surface ; hence 2.00-J-1.25 = 3.25, with a principal focal distance of 30.769 cm., which, multiplied by the ex- cess index, .52, gives 15.999 cm. radius of -4- curve. For the deep meniscus, the 6.00 surface with a principal focal distance of 16% cm., multiplied by the excess index, .52, gives 8.66% cm., radius ; to get a total power of + 2.00 the other surface would have to be -4- 8.00, EXERCISES IN PHYSICAL OPTICS 113 with a principal focal distance of 12.5 cm., multiplied by .52 gives 6.5 cm. radius. 56. Q. With a principal focal distance of 45 cm., and a radius of 22.5 cm., what is the index? A. Radius, 22.5, divided by 45, gives the excess index, .50, to which add 1.00, making total index 1.50. 57. Q. Principal focal distance, 50 cm. ; first conjugate focal distance 150 cm., what is the second conjugate focal distance? A. The first conjugate focal distance, 150, multiplied by the principal focal distance and divided by the difference between them, gives 75 cm. as the second conjugate focal distance. 58. Q. First conjugate focal distance 100 cm. ; second conjugate focal dis- tance, 200 cm.; what is the principal focal distance? A. Multiply the two conjugate focal distances together and divide by their sum; thus, 100X200 = 20,000-f-(100+200) 300 = 66%. Or, the first conjugate focal distance, 100, equals 1.00 diopter; the second conjugate focal distance, 200, equals .50 diopter; the two added, equal 1.50 which has a principal focal distance of 66%. 59. Q. Radius 20 cm.; index 1.52; first conjugate focal distance 100 cm.; what is the second conjugate focal distance? A. Radius, 20, divided by the excess index, gives the principal focal dis- tance, 38.46 cm. This, multiplied by the first conjugate focal dis- tance and divided by the difference between the two figures, will give the second conjugate focal distance 62.49 cm. 60. Q. First conjugate focal distance, 100 cm.; second conjugate focal dis- tance, 50 cm.; index, 1.52; what is the radius? A. Multiply the given distances together and divide by their sum to get the principal focal distance ; then multiply it by the excess index to get the radius. Thus, 100X50 == 5,000^(100+50)150 = 33%X-52 = 17.33% Or, convert both conjugate focal distances to diopters, add them, find principal focal distance and multiply by excess index to get radius. 61. Q. First conjugate focal distance, 120 cm. is shifted to 80 cm. and the change in first conjugate position causes the second conjugate point to be three times farther than when object was in first position; what are to two second conjugate focal distances and what is the power of the lens? A. The first conjugate focal distance, 120 cm., represents .83% diopters; the second position, 80 cm., represents 1.25 diopters; the difference between them is .41% diopters, which represents a principal focal distance of 240 cm., but as this is a change in first conjugate focal distance and a special effect is designated in the question, we mul- tiply the 240 by the times farther specified as the change in second conjugate focal distance, which is 3; therefore, 240X3 = 720 cm. as the second conjugate focal distance in relation with the second object position, 80 cm. ; and the power of the lens is the equivalent of 80, or 1.25 -f the equivalent of 720 or .1388 a total of + 1.3888 diopters. The second conjugate focal distance found to be 720 cm. is three A SYSTEM OF MATURE MEDICINE times farther than the second conjugate focal distance for the first object position, must be four times as far; hence, 720-J-4 = 180 cm. as the first second conjugate focal distance ; this is .555 diopters, which, added to the original position, 120, expressed in diopters, or 83% gives .83%-f .555 = 1.3888 diopters, power of lens. 62. Q. First conjugate focal distance, 60 cm., shifted to 100 cm., changes the second conjugate focal distance to one fourth as far from the lens as when object is in first position; what are the two second conjugate focal distances and what is the power of 'the lens? A. This is like the other, only reversed. The two distances given repre- sent respectively 1.66% and 1.00 diopter. Their difference is .66% diopters with a principal focal distance of 150 represented. This multiplied by %, (because that is the portion of conjugate focal dis- tance lost by the change of object position), gives 112.5 or .8888 D. as the second conjugate focal distance associated with the second position of object; therefore the lens is 1.00-)-. 8888 or 1.8888 diopters. As the second conjugate focal position found is only one-fourth as far from the lens as the original second position, it must be four times the one found; hence 112.5X4 = 450, or .2222 D. ; and this added to the diopters of the original position of object, 1.66% gives 1.8888 diopters power of lens, as before. 63. O. What is the principal focal distance of a lens, bi-convex, having radii 8 and 5 cm. and an index of 1.54? A. Multiply the two radii together and divide by their sum, after first multiplying it by the excess index. Thus, 8X5 =40-;- ( 13 X- 54) 7.02 = 5-698 = P F. Or, considered as two piano-curved lenses, the radius, 8, divided by excess index, .54, gives 14.8185 cm. focus, or 6.748 D. ; radius 5, divided by .54 gives 9.26 focus, or 10.799 D. Adding the two gives 17.547 D. with a principal focal distance of 5.698 cm. 64. Q. What is the principal focal distance of a lens with two radii, one 8 and the other -f- 4 cm.; index 1.60? A. This is worked in the same manner as A. 62, except that the sum of the radii in this instance is the difference between them, as one is and the other -4- : 4X8 = 32-K8 4 = 4X- 60)2.40 = 13% P. F. 65. Q. What is the index of a lens having radii -j- 6 12 cm. ; principal focal distance 24 cm.? A. By the fraction method % Vi2 = Viz, and 12 divided by the prin- cipal focal distance, 24, gives the excess index, .50, to which add 1.00. 66. Q. An object is 100 cm. from a 5.00 D. bicurved lens of equal radii ; what is the character of the image and where is it? A. The image will be formed by reflection from the first surface, 2.50; the principal focal distance by reflection is always one half of the radial distance. As no index is given we will assume it to be 1.52; hence as 2.50 D. represents 40 cm. focus, we multiply 40 by .52 to get the radius, which is 20.8 cm : and half of this is 10.4 cm. the EXERCISES IN PHYSICAL OPTICS 115 principal focal distance. This multiplied by the first conjugate focal distance, 100, and divided by the difference between them gives : 10.4X100 = 1040-^89.6 = 11.607 cm. = Cf 2 67. O. A +2.00 lens is placed 10 cm. in front of a +2.50; what is the power of the combination? A. The -4- 2.00 starts the rays toward a focus 50 cm. from it ; -f- 2.50 at 10 cm., receives the rays on their way to a focus 40 cm. beyond it, which equal 2.50, adding 2.50 makes a total of 5.00 D. with a focal length of 20 cm. ; adding the 10 cm. between lenses we have 30 cm. as the focal length of the combination, which equals a dioptric power of 3.331/0. 68. Q. A lens is -4- 2.00; radius of one side is 40 cm.; index 1.53; what is the radius of the -4- side? A. The radius of the side, 40, divided by the excess index, .53, gives 75.47 cm. focal distance, or 1.32 D. To get the -+- 2.00 effect, the other side must be a -4- 3.32 D. with a focal length of 30.2 cm., and this, multiplied by the excess index, .53, gives the radius, 15.96 cm. 69. Q. A. -4- lens has a principal focal distance of 50 cm. ; the radius of one surface is 15 cm.; index, 1.54; what is the radius of the curve on the other surface? A. The given radius, 15, divided by the excess index, .54, gives 27.77 cm. as the principal focal length, or 3.60 D. which is 1.60 D. more than is wanted; hence the other curve must be - with 1.60 power. Its focal distance, 62.5, multiplied by the excess index, .54, gives 33.75 as the radius of the surface curve. 70. Q. The radii of a lens are -4- 8 and 6 cm. ; the focal distance is 50 cm.; what kind of a focus is it and what is the index? A. It is a lens, because the radius is the shortest. By the fraction method, % % is .equal to % s % 8 =%8 or % 4 ; and 24, the new radius, divided by the focus, 50, gives .48 excess index, to which add 1.00, making index 1.48. 71. Q. What are the cardinal points and planes of a lens? A. They are the principal points and planes, nodal points and planes, optical center and its plane, principal focal points and planes. 72. Q. AYhat are the four essentials of a perfect dioptric system? A. Transparency, density, symmetry and adjustability. 73. Q. How are the optical centers of lenses found by calculation? A. If it be a bi-convex or bi-concave lens the sum of the two radii is taken as the denominator of a fraction, the numerator of which is one of the radii ; the entire fraction represents that portion of the thickness of the lens, from the side represented by the numerator, to the optical center. If it be a plano-convex or plano-concave lens, there being but one radius, the numerator and denominator of the fraction will be the same, as % or 1( % , therefore the optical center will be the thickness of the lens from the flat side, or at the apex of the curved surface. If the lens be a meniscus, -4- or , the short radius, multiplied by the lens thickness and the product divided by (the difference between the radii multiplied by the index) - - half 116 A SYSTEM OF MATURE MEDICINE the thickness of the lens; thus; with radii -|- 20 and - 40 lens 4 points thick: 20X4 = SO-:-(+20 40 = 0X1.50 = 30+2)33 = 2% points outside the curve of shortest radius. 74. Q. At what distance from any spherical lens must an object be placed to have the image formed at exactly the same distance from the lens? A. At twice the principal focal distance. 75. O. A bi-convex lens has its optical center one-fourth of the thickness of the lens from one surface ; what is the ratio of the two radii ? A. As 1 is to 3. 76. Q. The principal focal distance of the standard normal eye is 15.872 mm. from the optical center; how many units power is represented? A. Sixty-three. 77. O. The radius of the cornea is 7.8 mm.; index 1.3365; what is the first principal focal distance. A. The radius, divided by the excess index, gives 23.17979 mm. 78. Q. An eye is myopic 1.00 unit, how much will shorten the principal focal distance? A. A trifle less than a quarter of a millimeter : .247, to be exact. 79. Q. An eye is hyperopic 1.00 unit; how much will it lengthen the prin- cipal focal distance? A. A trifle more than a quarter of a millimeter ; .257, to be exact. 80. O. What would be the principal focal distance of the crystalline lens in air? A. The two radii 6 and 10 mm. being added, %+Mo or 1 %o+%o = 1 %o'. reduced, gives ^-75 as the radius of a piano convex lens of same power; and 3. 75-f-.4371 = 8.57927+ as principal focal distance. 81. Q. What are axial, corneal, lenticular, polar errors in the eyes? A. Axial is when the eyes are too long on the axis to fit the principal focal distance. Corneal is when the fault is in the cornea ; lenticular, when it is in the lens; polar when it is in the posterior form of the globe. 82. Q. What difference is there in the correction of these? A. None whatever. It is impossible to differentiate any except the corneal deformity. Part II OPHTHALMOLOGY CONTENTS, PART II. THIRTY-THREE ILLUSTRATIONS. NIV. Anatomy and Physiology of the Nervous System 119 XV. Anatomy and Physiology of the Eyes and Their Appendages. .127 XVI. Physiology of the Eyes Utilized to Measure Nerve Supply and Demand 135 XVII. Errors of Refraction in the Dioptric System How They are Compensated for by Accommodation and with Lenses.. 143 XVIII. The Neurometric Method of Analysis of Conditions Found By Examinations 155 XIX. Cyclophoria Often the Cause of Apparent Oblique Astigmatism 171 XX. Physiological Action of Prisms with Proofs of Their Unvalue 175 XXI. Heterophoria, "Muscular Insufficiency," a Nervous Exhibit. Treatment 181 XXII. Heterotropia, Strabismus, Squint, Cross-Eyes. Treatment for 185 XXIII. Alleged "Diseases" of the Eyes. Their Causes and Treatment. .189 XXIV. Objective and Subjective Methods Employed in Eye Testing. .205 XXV. Situation in Emmetropia, Hyperopia and Myopia, with the Lens Removed 217 XXVI. Seeing, Hearing, Smelling, Tasting, Matters of Education. .. .219 XXVII. Fitting Spectacle Frames an Important Matter 223 XXVIII. General Disorders, Symptoms of Which are Called "Diseases" 225 XXIX. Human Ills and Their Causes Viewed From a Rational Stand- point 241 XXX. The Color Sense. Color Ignorance. Theories of Color-Blind- ness XXXI. Physiognomy and Craniology .Indicate Temperament and Dis- position 261 XXXII. Some of the Idiosyncrasies of "Eminent" Authors 265 XXXIII. Idiosyncrasies which Exhibit in People of Various Professions and Trades 271 Appendix 279 Eponymes Ophthalmology 299 Glossary 305 Prefixes and Suffixes 311 Abbreviations Ophthalmology 311 Special Subject Index 312 Index 313 List of Illustrations . . .318 CHAPTER XIV. Anatomy and Physiology of the Nervous System. To the Ophthalmologist and Neurologist the Nervous System is Life. All else is subordinate and auxiliary to it. All human ills are exhibited through and by it. All pains and fevers are nervous symptoms. They are the two best friends of humanity generally and of the doctors in particular. The doctor who administers drugs to allay pain is a criminal and the person who takes the dope is foolish. The old-school vocabulary is replete with such words as "myalgia" (muscle pain). There is no such thing. All pains are nerve pains, hence are "neuralgia." The nervous system is the only thing capable of exhibiting sensation. Motion may be developed artificially, but the sensations are re- stricted to Nature and to Life as exhibited in the nervous systems of plants and animals. Life is Nature's practical expression of the law of Procreation by evolu- tion. It is exhibited by the generation of species in plants and animals. It dif- fers from the inorganic combinations of elements by possessing physiological activity, hence all such products are included in organic chemistry. Death is the automatic return to the inorganic state. It illustrates the limitations of Natural laws, and teaches that the so-called "spirit," ''mind," "soul," evi- dently culminate in something analogous to the physically proved evolution and that "purgatories," "heavens," "hells" and "personal gods" are merely products of imagination. The human race has been victimized by unscrupulous, self-constituted "leaders" or "authorities" ever since there has been a human race. Endowed by the Creative Power with a mentality superior- to that of the lower animals it developed ego. Ergo, presto! it acquired a notion that it is the "image of its creator'' and to prove it wrote books and advertised them as the "word," dictated to the conspirators by the creature of their imagination and a fool people believed the stuff because it flattered their ego. They have been believing it more or less all through the ages, because of their ego. Even our good friend, Colonel Robert G. Ingersoll, fell for it when he said : "All I can say about immortality is, I do not know. There was a time when I was not. Now I am ; and it may be that it is no more wonderful, now that I have a start, that I should live forever. We love, and those we love die ; and we cling to the wish, to the hope that we may meet again. Love was the first to dream of immortality and as long as we love we shall hope." 120 A SYSTEM OF MATURE MEDICINE Poetry? Yes, to be sure. Nothing more. I can find no more reason for hope of a heaven than I have found for fear of a hell. They are both "dreams," induced by environment, fear, credulity and indigestion. None of the "words" has told anything about Life and how to preserve it, or how to propagate it. Their influence has been altogether bad. It has brought strife, blood-shed, misery, want, woe, poverty, opulence, religions, drugs, alleged "laws," unions, sluggers, murderers, politicians and movie actors. The people cater to them all and hope. Far be it from me to deny them the "blessed privilege." I have a few remarks to make in this chapter about Life, and the fol- lowing diagram is an outline of my proposition : J Cerebrum \ , T \ Ventricles Cerebellum... . / Receiver _...,. \ Distributor Cerebro-Spinal Cord. Ganglia / Large \ Small Branches... . / Sensory Motor Nervous System. . . , Systemic / Organic , General J I Locomotor / Flexor Sympathetic f Chemical.. . / Smell [ Special Taste I Mechanical / Vision \ Hearing The Nervous System, anatomically, consists of the Brain, Spinal Cord, Trunk Lines and Branches. It ramifies every structure of the body except the hairs, nails, parts of the teeth and the cornea-sclerotic layer of the eyes. The branches range in size from the great sciatics, which are sometimes three-fourths of an inch broad, to so small they cannot be traced with the microscope. At points where branches are given off there are ganglia (knots). Wherever many nerve branches meet they form plexuses (net- work). For convenience the trunk lines are divided into two sets: Cranial, twelve pairs ; Spinal, thirty-one pairs. The Cranial have names and num- bers : 1. Olfactory: Origin, limbic lobe, optic thalamus, island of Reil ; dis- tribution, Schneiderian membranes of nose ; function, sense of smell. 2. Optic: Origin, cuneus, (wedge), in each occipital lobe; distribu- tion, to retinae ; function, sense of vision. 3. Motor Oculi: Origin, aqueduct of Sylvius; distribution, to all eye muscles except the external recti and superior oblique ; function, motor. 4. Trochlear (pulley) or Patheticus: Origin, valve of Vieussens in roof of fourth ventricle superficially ; deep origin, floor of the fourth ventricle; distribution, to superior obliques of eyes ; function, motor. 5. Trigeminus (three branches) or Tri- Facial : Origin, floor of fourth ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM 121 ventricle ; distribution, skin and muscles of face, tongue, upper and lower teeth and the eyes, via third nerves; function, sensation and motion. 6. Abducens: Origin, fourth ventricle; distribution, external recti of eyes ; function, motor. 7. Portio-Dura : Origin, fourth ventricle ; distribution, face, ears, palate, tongue, etc. ; function, motor. 8. Auditory : Origin, restiform (cord-like) body of the Medulla Ob- longata; distribution, internal ear; function, sense of hearing. 9. Glosso-Pharyngeal : Origin, fourth ventricle; distribution, tongue, pharynx, etc. ; function, sense of taste. 10. Pneumogastric or Vagus or Par Vagum: Origin, fourth ventricle; distribution, oesophagus, lungs, heart, stomach; function sensation and mo- tion. 11. Spinal Accessory: Origin, fourth ventricle; distribution, sterno-clei- do-mastoid, trapezius muscles, etc. ; function, motor. 1~>. Hypo-Glossal (under tongue): Origin, fourth ventricle; distribu- tion, hypo-glossus and hyoid muscles; function, motor. The Spinal nerves are subdivided into: Cervical (neck) 8 Dorsal (back) 12 Lumbar (loins) 5 Sacral (sacred) 5 Coccygeal (beak) I 1 Total 31 Their distribution is by way of ganglia and branches. The ganglia are: Superior. Middle, and Inferior Cervical, twelve Thoracic, five Lumbar, five Sacral, on each side of the vertebral column and one Coccygeal, or Impar, on the Coccyx. These ganglia and their connections up and down either side of the spine afford a circulation to and from the brain independent of the cord, and, with the peripheral unions of a plexiform nature constitute what is known as the Sympathetic System. The principal Spinal nerves are the Splanchnics, Superior, Middle and Inferior, from the middle and lower Thoracic Ganglia to the abdominal viscera (organs) ; the Obturators, from Lumbar Region to hip joints ; the "Sciatics, from Sacral Region to legs ; the Anterior Crural, from Lumbar Region to thighs ; the Dorsal, to muscles and skin of trunk ; the Pudics from sacrum to the sex organs and anus. Physiologically the nervous system consists of the distribution of elec- trical force, acquired from Chemical Reactions on food and from the Me- chanical Friction of the body particularly the muscular division. The energy generated is first sent to the Cerebellum and from there it is dispatched to all parts. The current toward the brain is called afferent; that from the brain is efferent. The structure of the anatomical system is white and gray matter; the first fibrous, the second cellular. The Physiological Nervous System is the electrical current operating the functions of Sensation and Motion. It is derived from the body and food 122 A SYSTEM OF MATURE MEDICINE elements, of which there are fourteen, representing eight chemical groups: 1. Nitrogen and Phosphorus. 2. Oxygen and Sulphur. 3. Hydrogen. 4. Iron. 5. Chlorine and Fluorine. 6. Potassium and Sodium. 7. Calcium and Magnesium. 8. Carbon and Silicon. Nitrogen, Oxygen, Hydrogen, Fluorine represent Life. Phosphorus, Iron, Sulphur, Chlorine ) ,. ,-, , . , r . represent sustenance Potassium, Sodium, Calcium, Magnesium] Carbon and Silicon represent fat and waste. The forms in which these elements are delivered comprise mixtures and compounds. Air is a mixture, four-fifths nitrogen and one-fifth oxygen ; water is a compound, eight-ninths oxygen and one-ninth hydrogen. Water, hydro-chloric acid, sodium chloride and a few other combinations are simple compounds ; the rest are all complex salts, such as nitrates, sulphates, phos- phates, etc., formed by the action of active principles on the metal bases, potassium, sodium, calcium, magnesium and iron, and on the non-metalic base, carbon. The latter being an essential in a limited degree, after which it is a trouble maker. But this story is too long for this volume and will be reserved for Volume II. In the earliest stages of the development of the anatomical brain the cerebro-spinal structure is called the Neural Tube, which gradually enlarges, dividing into three Vesicles, or cavities. Later these develop into the Ventricles of the brain and from the thickening of the walls of the tube are developed the Lobes of the brain and the substance of the Spinal Cord. The membranes, or meninges, are the Dura Mater (hard mother), Arachnoid (spider's web) and Pia Mater (tender mother). The first is a layer of protection to the brain and cord; the last is a convoluted (rolled) layer; the Arachnoid lies between the others, separated from the inner one by a lymph space ; it does not dip down into the fissures between the con- volutions of the Pia Mater; it does extend around cranial nerves until they emerge from the skull. The Dura Mater includes : The Falx (sickle) Cerebri, an arched pro- cess, or partition, which dips down between the two hemispheres and con- tains, in its upper and lower margins, the Superior and Inferior Longitudinal Sinuses (canals), substitutes for veins; the Tentorium Cerebelli, a plate supporting the posterior lobes of the hemispheres of the Cerebrum, covering the Cerebellum and enclosing the Lateral and Superior Petrosal Sinuses; Falx Cerebelli, a partition between the Lateral Lobes of the Cerebellum extending from the Tentorium to the Foramen Magnum (opening for cord to spine) ; Diaphragma Sellae, a horizontal circular fold which forms a roof for the Sella Turcica (Turkish Saddle) which contains the Pituitary (phlegm) Body, in which some profess to believe the soul is housed ; the Pacchionian Bodies, near the Superior Longitudinal Sinus, the function of which none know. ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTF.M The Sub-Arachnoidal Space contains Cerebro-Spinal Fluid as do also the Third and Fourth Ventricles and the Aqueduct of Sylvius which con- nects them. The Pia Mater is highly vascular and nervous, receiving blood from the Internal Carotid and Vertebral Arteries, it distributes to the hemispheres through great numbers of plexuses by dipping down into all the furrows (sulci) between the convolutions (gyri) of the substance of the hemispheres which consists of a medullary (marrow) center of white matter covered by an outer layer of gray matter known as the cortical (bark) stratum. The blood circulation is worth more than a mere passing mention at this point. The Vertebral arteries enter the skull through the Foramen Magnum, pass upward and forward in front of the Medulla Oblongata and unite to form the Basilar artery, which has five branches on each side : The Transverse, Internal Auditory, Anterior Inferior Cerebellar, Superior Cerebellar, Posterior Cerebral. The Internal Carotid arteries enter through canals in the petrous portions of the Temporal bones, then branch into eight on each side : Tympanic, Arteriae Receptaculi, Anterior Meningeal, Oph- thalmic, Anterior Cerebral, MirMle Cerebral, Posterior Communicating and Anterior Choroid. The Circle of Willis is formed by an anastomosis (con- nection by special branches) of the Internal Carotids with the Basilar; the object is, evidently, to get around the upper body of the Sphenoid bone, the portion known as Sella Turcica ; it is formed in front by the Anterior Cerebrals and Anterior Communicating, on the sides by the Posterior Com- municating to the Posterior Cerebrals, which, with the end of the Basilar, form the posterior portion of the Circle which, no doubt tends to equalize the circulation. The Middle Cerebrals are the largest branches of the In- ternal Carotids; they pass obliquely outward along the Fissures of Sylvius and opposite the Islands of Reil divide into terminal branches. The Ophthalmic leave the Internal Carotids as they emerge from the Cavernous Sinus and enter the Orbits through the Optic Foramen below and outside of the Optic Nerve. The Anterior Cerebrals and all other branches an- astomose freely and finally end in Terminal Arteries, that is those small vessels which have no further branches. The Posterior Cerebrals and other branches of the Basilar supply the Cerebellum and posterior portions of the Cerebrum. The Veins of the brain do not accompany the arteries ; they are without valves and are called Sinuses (canals), but need not be confounded with cavities in bones, also called sinuses ; they are Superficial and Deep, of course. The first named are also called Cortical and the second are known as the Veins of Galen. The latter pass out of the brain substance at the Great Transverse Fissure, about the middle of the under side, after receiv- ing branches from all directions, and empty into the Straight Sinus, which, with the Superior and Inferior Longitudinal, Lateral, Occipital, Superior Petrosal, Circular, Cavernous and Inferior Petrosal Sinuses deliver venous blood to the Internal Juglar Vein. The Circular Sinus is formed by the two Cavernous Sinuses on the sides and the Anterior and Posterior Inter- cavernous Sinuses which connect them, in the same region in which the Circle of Willis is located, and it is, doubtless, for the same purpose. The External Carotid Arteries and their corresponding Veins supply the neck 124 A SYSTEM OF MATURE MEDICINE and face; they will be treated in Volume II, which will, necessarily devote much space to anatomy and physiology of the entire body. The duality of the brain is the Cerebrum and Cerebellum or the In- tellectual and Mechanical. Its quadrality is completed when we refer to the Two Hemispheres of the Cerebrum, the Cerebellum and Medulla Oblongata. The duality of the Cerebrum is its Hemispheres, and its quadrality is completed by Lobes and Ventricles. Each hemisphere is divided into seven Lobes; the two hemispheres form seven Ventricles in the space between them. Really there are only four Lobes on each side : Frontal, Temporal, Parietal, Occipital; the Central (Island of Reil), under the Parietal, between the Temporal and the median line, the Limbic, under the anterior beak of the Corpus Callosum (callous body) in the middle head, and the Olfactory, under the Frontal centrally, are merely processes of the other eight. The same truth applies to the Ventricles: The Fourth is lowest, lying down be- tween the Cerebrum and Cerebellum, over the Medulla Oblongata; above it and slightly forward is the Third, connected with the Fourth by the Aque- duct of Sylvius; a little further upward and forward are the Right and Left Lateral Ventricles, connected with the Third by a Y-shaped opening known- as the Foramen of Monro; the other Ventricles are merely clefts between the anterior portions of the hemispheres. The Third and Fourth Ventricles and the Aqueduct of Sylvius contain Cerebro-Spinal Fluid; the others are empty, unless they fill by a rising tide in the lower Ventricles dur- ing excitement. I have a theory that something of this nature occurs and that the Lateral Ventricles are for the purpose of maintaining equilibrium of the Spinal Fluids just as the Circle of Willis and the Circular Sinus bal- ance the arterial and venous currents. The absence of such an arrangement, or the deficient development thereof may account for the exhibits of cerebral distress in some cases of indigestion or other physiological irritation ; for "strokes" of "apoplexy" and for the paroxysms of "epilepsy," which a Cin- cinnati Medical Trust doctor says is caused by a bug. The contradictory evidence I have found against my theory is our successful treatment of "epilepsy." Still we have always cautioned such patients to be constantly 'on guard against over-eating, indulgence in sweets and starchy foods and gave strict injunctions to avoid excitement, such as exhibits in anger, politics, etc. The Fissures of the Cerebrum are for the purpose of blood circulation. They are the Longitudinal, separating the ? hemispheres, (the Corpus Cal- losum forms the floor of this fissure in the middle head) ; the Fissures of Sylvius on each side, separate the Frontal from the Temporal Lobes and carry the Middle Cerebral Arteries; the Fissures of Rolando, on the superior surface of each side, from the Longitudinal Sinus, about its center, down and forward, separate the Frontal and Parietal Lobes; the Parieto-Occipital or Lambdoid are short ones, on each side, separating the Parietal from the Occipital. These four are all of the external ones. There are similar pro- visions on the internal or under surface, the principal one being the Trans- verse Fissure, of a horse-shoe shape, which transmits the Vena Magna Galeni, or Veins of Galen, mentioned in another paragraph. The Cerebellum is composed of white matter, centrally, and gray mat- ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM 125 ter, externally. It is not convoluted, but is more like a knotted cord. It comprises a central division, the Vermiform (worm-like) process and two Lateral Lobes. It is the storage battery of the nervous system. It has fissures and lobes to the number of nineteen and its connections with the Cerebellum and Medulla Oblongata are as complicated as the most intricate electrical apparatus. No one has yet mastered its mechanism. The Medulla Oblongata or Spinal Bulb is the lowest division of the Power House and is the beginning of the Spinal Cord. The Pons (bridge) Varolii is situated on top of the Medulla and is really a part of it, being the connecting link between the Cerebrum, Cerebel- lum and the Medulla Oblongata. It is almost cubic in form, one and one- half inches on each side ; it lies between the hemispheres of the brain ; it is full of nerve cells and may be regarded as the switch-board of the system. Ganglia are miniature duplications of the Cerebellum and while an- atomically natural products, the same as a knot in a tree where branches leave it, they have a physiological function similar to the regulators of electric curents at points where they are taken from main lines into build- ings. There are a great many of these and sometimes they are formed in plexuses, the branches of nerves acting as roots from which the knots are formed. An example of this is found in the Solar Plexus, which is a general term covering the Phrenic, Renal, Gastric, Splenic, Hepatic, Superior Mesen- teric, Aortic and Supra-Renal Plexuses, in which they are many small ganglia and two Semi-Lunar (half-moon) ones, which are the largest in the body. This aggregation lies behind the pancreas, in front of the crura (legs) of the diaphragm, close to the spine and aorta, just above the kidneys. The connections with the spinal ganglia are such that in cases of diarrhoea pres- sure put on the spinal column in the lower dorsal region will arrest the trouble by stopping the runaway current. The treatment must be firm but gentle. There is no need of hurting patients. For babies I slip my hand under the back as they lie and put on the pressure by lifting; for others I seat them in front .of me and have them lean back over my knees, aiding by pulling upward and backward under their arms; when it. begins to hurt I relax a little, and, holding my knees steady, rock my body back and forth, sidewise, carrying the patient with me. One or two treatments is usually sufficient to stop the worst case. The so-called Sympathetic System is simply the Physiological differen- tiated from the Anatomical system. Its general function is Sensation and Motion, or Systemic and Locomotor, the first applying to the organic and vasomotor currents ; the second to the muscular flexion and extension re- quired in our daily work. Its special function is that of feeling, including chemical senses of smell and taste and the mechanical ones, hearing and seeing. There are so many contributing causes of nervous derangements in con- nection with eye defects, which ought to be looked after by the Opthal- mologist, that it has been deemed advisable to present this brief outline of the nervous system in order to encourage more thorough preparation than is usually found to have been accorded by those in eye practice. 126 A SYSTEM OF MATURE MEDICINE This plate shows the relation between the two eyes and the arrangement of the muscles, which, with the exception of the inferior oblique, arise from the cartilaginous substance in the apexes of the orbits. 1-1 : External recti ; 6th nerves ; turn eyes out. 4-4 : Internal recti ; 3d nerves ; turn eyes in. 3-5 : Superior obliques ; 4th nerves ; prevent eyes rolling on their axes, outward at the top. The inferior obliques, not shown in plate, arise from the orbital plates of the superior maxillary bones, about opposite 3 ; they are operated by the 3d nerves and are active antagonists of the superior obliques. See Chapter on Cyclophoria. 6 : Superior rectus of left ; 3d nerve ; turns eyes up. 2 : Inferior rectus of right ; 3d nerve ; turns eye down. 7 : The optic or 2d nerve, to the retina ; visual sense. 8 : Optic nerves commissure or switch-yard, where the nerves divide and cross over; the macula of the right eye is supplied by the left nerve and that of the left by the right nerve ; the nasal half of the retina of each eye is supplied by the nerve from its own side of the head. It is through this nervous arrangement that binocular vision is possible. 9. Optic nerve sheath enclosing optic nerves and retinal vessels. The levator palpebrae superioris muscles, not shown in plate, also have their origin in the apexes of the orbits. CHAPTER XV. Anatomy and Physiology of the Eyes and Their Appendages. The orbits are the two pyramidal cavities in the skull which contain and protect the eyes. The openings into each are: The optic foramen, for the optic nerve and opthalmic artery; the sphenoidal fissure, a triangular- shaped opening, also known as the foramen lacerum anterius, which trans- mits the third, fourth, sixth and branches of the fifth nerves, the orbital branch of the middle meningeal artery, a recurrent branch from the lachrymal artery to the dura mater, and the ophthalmic vein; the spheno-maxillary fissure, for the passage of the orbital branches of the superior maxillary nerve, the ascending branches from the spheno-palatine (Meckel's) ganglion, and infra-orbital vessels ; the infra-orbital canal connecting with the face through the infra-orbital foramen; the canal for the nasal duct; the anterior and posterior ethmoidal foramina for the ethmoidal vessels and nasal nerve; numerous small foramina for the transmission of vessels and nerves to nourish the bones forming the orbits, which are eleven in both orbits, seven forming each, but three cranial bones, the frontal, ethmoid and sphenoid, form part of each orbit while the facial bones, superior maxillary, malar, palate and nasal, are rights and lefts. The roofs are formed by the orbital plate of the frontal and the lesser wings of the sphenoid, the latter behind. The outer walls are formed by the malars in front and by the greater wings of the sphenoid behind. The floors comprise the orbital pro- cesses of the superior maxillary bones, principally, with small portions of the malars in front and of the palates behind. The inner walls are formed by the nasal processes of the superior maxillaries, the lachrymal, the os planum of the ethmoid, and the body of the sphenoid. There are depres- sions in the roofs for the lachrymal glands, externally, and for the carti- laginous pulleys of the superior oblique muscles, internally. The apexes of the orbits are directed backward and inward, but it does not follow, as a corollary, that the optic axes of the two eyes are divergent, as has been stated by garrulous anatomists and reiterated by others, as we have shown reasons why such a condition would be incompatible with Na- tural laws. The orbital fascia, or connective tissue, forms the periosteum of the orbits. In some places it is membranous, in others cartilaginous, tendinous, and even muscular ; it includes Tenon's capsule, which surrounds the pos- terior two thirds of the globe, (sometimes called Bonnet's), sheaths of muscles and the muscles, nerves, vessels, areolar tissue and fat lying between the eyes and their orbits. 128 A SYSTEM OF MATURE MEDICINE The muscles of the globes, superior, inferior, internal and external recti, superior and inferior oblique, and the levator palpebrae superioris, originate in the fascia in the apexes of the orbits, with the single exception of the in- ferior obliques, which have their origin in depressions of the superior max- illary bones just in front of the equator of each eye and pass outward and backward under the eyes, having their insertions on the posterior external sides of the eyes between the inferior and the external recti. The functions of these muscles are respectively: The superior recti, to raise the eyes to any desired plane ; the inferior recti, to lower the eyes' to any plane ; the interni, to converge the optical-visual axes for near work ; the external recti, to restore parallelism of the axes after convergence and to rotate the eyes outward, one at a time in connection with convergence of the other ; the superior and inferior obliques, to hold the eyes in balance on their axes not to rotate them obliquely, as is stated by nearly all anatomists. II their story was true, when the inferior oblique of the right eye pulled that eye in and down behind and out and up in front the superior oblique of the other eye would have to push out and down to turn the front of that eye up and in. In the chapter which treats of oblique astigmatism, these oblique muscles play an important part. The nerve supply of the eye muscles all comes from the third cranial nerves, except that the fourth nerves supply the superior obliques, the sixth pair supply the external recti and the ophthalmic division of the fifth pair reinforce the third. The blood supply is from the ophthalmic arteries, from the internal carotids, from the common carotids, from the aorta, from the heart. It returns' through the ophthalmic veins, to the cavernous sinuses, to the petrosal sinuses, to the internal jugular vein, to the subclavian vein, to the superior vena cava, to the heart. The orbital arteries, from the temporal arteries, are distributed to the upper orbital margin. The blood supply is distributed chiefly to the muscles and to the second layer of the globe, the choroid, which is the medium of nourishment and nervous activity of the optical apparatus. The ophthalmic arteries leave the internal carotids just as those vessels emerge from the cavernous sinuses and enter the orbits through the optic foramina just below and outside of the optic nerves; they then pass over to the inner walls and divide into branches which are nu- merous and may be classified as the orbital and ocular groups; the former comprise the lachrymal, supra-orbital, anterior and posterior ethmoidal, in- ternal palpebral, frontal, nasal, and they supply the parts indicated by their names ; the latter include the long, short and anterior ciliary, muscular and arteria centralis retinae. The last named enters the globe with the optic nerve through the porous opticus and immediately divides into superior and inferior branches which spread into nasal and temporal branches and capillaries which nourish the retina. The branches of these arteries do not anastomose with each other hence are called "terminal" arteries. The ophthalmic veins, superior and inferior, begin at the inner angles of the orbits, have the same courses, reversely, as the ophthalmic arteries, but the superior pass through the sphenoidal fissures and empty into the cavernous sinuses ; they receive from the lachrymal, anterior and posterior ethmoidal, THE EYES AND THEIR APPENDAGES 129 muscular branches, and veins from the eye-lids ; the inferior sometimes pass through the spheno-maxillary fissure and empty into the sinus by separate openings ; an unimportant matter save that it illustrates the inconstancy of some anatomical features. All anatomies contain such exaggerated descriptions and illustrations of the structures of the eye that they are confusing to the student, hence worse than worthless. Fig. 97 shows a horizontal section of the eye enlarged for convenience. A is the aqueous humor, filling the space between the cornea and lens, in which the iris, 10, floats. C is the crystalline humor which forms the lens, contained between the anterior and posterior capsules 2 and 3. V is the vitreous humor which fills the globe. 1 is the cornea; 4 the retina; 5 the pigment layer; 6 the choroid ; 7 the sclerotic; 8 the optic disc, where enter the retinal nerves and arteries and where the veins of the retina find their exit; 9 is the canal of Schlemm ; 11 the canal of Petit; 12 the zonule of Zinn ; 13 the suspensory ligaments; 14 the ciliary processes; 15 the circle of Zinn, around the optic disc field where the choroidal vessels pierce the sclerotic ; 16 the equator of the globe in front of which are the chief attachments of the rectus muscles and behind which are the attachments of the obliques. The Sclera (hard) or Sclerotic Layer, which is the outer one of the globe, extends forward to the cornea, constituting about five-sixths of the layer of protection; it is practically without nerves or vessels, is a dense, fibrous 130 A SYSTEM OF MATURE MEDICINE structure, with a lymph space between it and the Capsule of Tenon; it is perfectly smooth except where the muscles have their insertion ; the recti are attached about three-eights of an inch from the sclero-corneal margin, the obliques on the posterior temporal sides. The Tunica Albuginea, or "white of the eye" covers the muscles anteriorly. Posteriorly and on the inner half of each globe the sclerotic is pierced by the optic nerve and its accompanying vessels at the porous opticus, or what is seen with the ophthalmoscope as the optic disc, and in a field around this, the circle of Zinn, by the vessels to and from the Choroid. Anteriorly, at the edge of the sclera is the Canal of Schlemm which receives vessels from the interior of the eye and communicates with the conjunctiva externally. Ordinarily this is invisible, but in severe internal congestion it sometimes becomes injected and appears as a bright red ring around the margin of the cornea. The Cornea (horn) is transparent to admit light to the interior of the globe; it is of sharper curvature than the sclera to make up in angle of inci- dence what the refracting media lack in density. It comprises an anterior epithelial layer, an anterior elastic layer, (Bowman's), the substantia propria or cornea proper, a posterior elastic layer and an endothelial layer. The posterior elastic layer is known as the membrane of Descemet or Demours. The imagination of anatomists has been overworked to describe the purpose of the separate layers but it is safe to pass it as part of the plan of Nature and confine ourselves to matters within our comprehension. The cornea contains no nerves or blood vessels except such microscopic ones as are necessary to its nourishment. In rare cases of long-continued injection of the vessels of the orbits, eyes and lids, corneal vascularization develops and almost always destroys vision permanently. This is one of the- many reasons why the public should be taught to have the eyes looked after by competent practitioners before the evil days come. The second layer is one of nourishment and mechanical activity. It in- cludes the Choroid, Ciliary Body (Processes) and Iris. The Choroid is prac- tically all vessels and nerves, the veins being multitudinous and arranged so they converge toward four or five centers about the equator of the globe where they form large trunks, the venae. vorticosae, which pierce the sclera and communicate with the ophthalmic veins ; the arteries extend forward into the Ciliary Body accompanying the Ciliary Nerves and branches of both are sent to the Iris, particularly its margin, where they connect with the Canal of Schlemm, which also connects with the anterior chamber through the spaces of Fontana. The veins of the Ciliary Body are also numerous and empty into the choroidal veins of which they are a part. In cyclitis, from long continued efforts to overcome hypermetropia, the injection of the Ciliary Body -becomes a hypertrophy and if not reduced will develop what is com- monly called Glaucoma and the eye will be lost. This trouble appears first in the fixing eye, because, while both are injected the fixing eye is the first to demand help; as a result the other eye is usually saved. The public should listen to reason instead of to rascals who, claiming to be "authorities," decry the wearing of glasses, particularly if fitted by non-medical practitioners. It is a humiliating fact that the average oculist knows absolutely nothing about physical or physiological optics, and really believes that the fitting of glasses THE EYES AND THEIR APPENDAGES 131 is a minor matter, that sore eyes need medical treatment, when really properly fitted glasses and a few days rest is all that is needed in nearly all cases. The Ciliary Body comprises folds of Choroid, the suspensory Ligaments, a cartilaginous zone radiating from near the edge of the crystalline lens, being separated from it by the Canal of Petit and the Zonule of Zinn, the first of which is like a pneumatic tire around the edge of the lens and the second is a network of fibres connecting the tire with the suspensory ligaments ; the office of the first is to pull against the suspensory ligaments which it cannot quite overcome, hence, without assistance from the sphincter muscle and its nerve, (Muller's Muscle), interwoven circularly with the suspensory liga- ments, which completes the mechanism of accommodation, the lens would remain in a static condition. In old age, when the "pneumatic tire" loses its elasticity, the sphincter muscle and nerve are unable to do all the work and artificial assistance is required for near work. This is called Presbyopia, the vision of old age. The Iris (rainbow) is a muscular curtain, formed of radiating and cir- cular fibres, with an adjustable opening in the center, the pupil. The circular fibres are innervated by branches of the ciliary nerves and regulate the amount of light admitted by contraction and relaxation; the radiating fibres, being elastic, are the dilators, without innervation. The structure is invested with a pigment layer varying in color from black to a pale green. The very dark ones shut out all light except that which passes through the pupil; the lighter ones admit some light through the body of the iris. In rare cases there is no pigmentation, the iris hangs in the aqueous humor like a lace curtain and the retina is so overwhelmed with light that it actually dances from the irritation this has been called a "disease," "St. Vitus' Dance." Such condition is called Albinism and because of their white hair and general lack of pigment in the skin such people are called Albinoes. The Iris is a continuation of the ciliary body but is connected with the posterior elastic layer of the cornea by the pectinate ligament. In this ligament are the spaces of Fontana, mentioned in a preceding paragraph. Much has been written about Iritis; it is largely humbug. The Iris hangs in a chamber filled with salt water and only its edge could be involved even in the worst cases of cyclitis. Operations are never needed and could do no possible good. See chapter on "so-called diseases of the eyes." The Tapetum Nigrum or layer of pigment lines the Choroid and extends forward through the Ciliary Body to the Iris. Posteriorily it is a layer of cells filled with granules, evidently for the same purpose that the ground is used by electricians to take care of surplus electricity and prevent burning out of the delicate visual apparatus of the retina. Some anatomists describe this layer as part of the Choroid; others as part of the Retina. It is clearly neither, but is a distinctly separate layer. The Retina (net) is the innermost layer and comprises a network of nerve filaments, arteries, veins and capillaries beginning- at the edge of the optic disk and extending forward to the edge of the Ciliary Body about on a plane with the posterior surface of the lens. So far as the nervous portion is concerned it is entirely invisible with the ophthalmoscope, only the vascu- lar stratum being seen. Technically, as learned from microscopic sections 132 . A SYSTEM OF MATURE MEDICINE the Retina consists of many layers of nervous structure, which are listed from without inward as follows : 1. Layer of rods and cones, (Jacob's Membrane). 2. Membrana limitans externa. 3. Outer nuclear layer. 4. Outer molecular layer, or granular layer. 5. Inner nuclear layer. 6. Inner molecular layer. 7. Ganglionic layer. 8. Stratum opticum ; layers of nerve fibres. 9. Membrana limitans interna. 10. The fibre of Muller (or Henle) connecting the above. The Optic Disc is about one-eighth of an inch in diameter and is approx- imately its diameter from the posterior pole of the eye on the nasal side. The field around this pole comprising a space about twice as large as the Optic Disc is called the Macula Lutea (spot-yellow). It is the portion of the Retina on which images are formed chiefly, hence is most highly devel- oped. There is no visible spot, notwithstanding the asseverations of Som- mering and the reiterations of anatomists who never saw the inside of an eye. The "fovea centralis" is located in the same manner an engineer locates a section line, not as an alleged "authority" locates a glass of beer. The space in front of the lens and behind the cornea is filled with Aqueous Humor and the Iris divides it into anterior and posterior chambers. This humor is the only one of the three included in the dioptric system that is changeable and renewable. It is connected with the lymphatic system and receives from it, discharging through the spaces of Fontana into the Canal of Schlemm, thence into the venous system. In operation for cataract this humor is all lost but soon refills the space after the cornea is replaced. The Crystalline Humor which, with the anterior and posterior capsules, forms the lens, is composed of many layers, beginning with a bi-convex nucleus, like the "aplanatic" lens described elsewhere, and finishing with anterior and posterior layers of negative meniscus form, the whole being soft and adjustable to changes in the capsular surfaces caused by pressure of the Canal of Petit, or "pneumatic tire," during accommodation. It was, doubtless, made thus striated for the same purpose the "aplanatic" lens is made, namely, to prevent chromatic aberration ; hence "color-blindness" is most likely due to homogenity of construction of the lens rather than to any abnormality of the rods and cones of the Retina, as proposed by other writers. The Vitreous Humor, which fills the globe, is a semi-fluid of vesicular structure ; it is evidently in constant motion, because in some conditions of body chemistry there appear to the victims "floating specs" which are opaque vesicles, and these opacities are dissipated by systemic treatment. It is the development of this humor which fixes the status of the eye in many in- stances with reference to Emmetropia, Hyperopia and Myopia; its overde- velopment occasionally produces Malignant Myopia and Posterior Staphy- loma, a backward bulging of the globe until the Chordid and Retina are torn THE EYES AND THEIR APPENDAGES 133 from their attachments to the Sclera, destroying the Macula and, of course, vision. The Hyaloid Membrane lines the entire cavity of the globe, surround- ing the Vitreous Humor. In embryo it was a canal leading to the Crystalline Lens ; after the lens was fully developed it enlarged with the filling in of Vitreous and became a membrane ; it is still, probably, a source of nourishment to the Vitreous. The Appendages of the eyes are the Conjunctiva, Lachrymal Glands, Lachrymal Sacs, Nasal Ducts, Eyelids and Eyebrows and the Muscles operating them. The Conjunctiva is the mucous membrane which lines the lids and covers the anterior portion of the eye. It is a highly vascular and nervous structure, for protection against foreign bodies, and, being lubricated by the flow from the Lachrymal Gland, the Lids work smoothly over it. The Lachrymal Gland is situated in a depression in the upper, outer angle of the roof of the orbit, receives its supplies from the Lymphatic System and delivers through several small ducts piercing the Conjunctiva. The Lacus Lachrymalis at the nasal end of the opening between the eyelids, with its puncta lachrymalia or openings leading to the Lachrymal Sac and the Nasal Duct, take care of the flow of tears ordinarily. When there is an overflow for any reason it is no excuse for probing the Nasal Duct. Usually the cause is uncorrected ametropia, which is easily and permanently fixed with glasses. The Lids or Tarsal Cartilages (Palpebrae) for protection from light and other harmful influence and for the distribution of the lachrymal fluid, are composed of skin, superficial fascia, fibres of the Orbicularis Palpebrarum Muscle, palpebral and orbito-tarsal ligaments ; the upper lid also contains the Levator Palpebra Superioris Muscle. The lids are supplied liberally with nerves, blood vessels and lymphatics ; in addition there are Sebaceous Glands known as Meibomian Glands, which lie in grooves on the inner surfaces having the appearance of bunches of small pressed grapes ; their ducts open on the free margins of the lids and their secretion is utilized to moiste'n the edges. What is commonly called a Stye or Hordeolum is usually a Meibomian Cyst. The Muscles of the Lids are : The Orbicularis Palpebrarum, which,, as a part of both upper and lower lids, appears to be more for elasticity than any- thing else ; it is supplied with energy via the Seventh Cranial Nerves. The Tensor Tarsi, usually described as a short muscle attached to both lids at the inner canthus, or angle, really composes the entire edge of the lids; it receives its nerve supply from the Third Cranial Nerves; its office is to hold the edges of the lids tight against the Cornea and by intermittent jerks from the nasal side, (winking), distribute the lachrymal fluid and draw it toward the Lachrymal Sac. The Levator Palpebra Superioris, is an orbital muscle, originating in the apex of the orbit and coming out over the eye is inserted into the upper lid as a suspensory antagonist to the Tensor Tarsi (Horner's Muscle) ; it, too, is operated by the Third Nerves. The Corrugator Super- cillii are scarcely eye muscles ; they are situated between the brows and 134> . A SYSTEM OF MATURE MEDICINE have slight attachment to the inner upper corners of the lids; their contrac- tion corrugates the forehead, hence their name; they are supplied by the Third Nerves. The student should observe the muscles in the performance of their functions, remembering that all depends on their nerve supply; noting that sometimes two similar muscles work together, as the internal recti in con- vergence, and sometimes they work singly as in looking to the right or left one external and one internal rectus work together. All of the extra-ocular muscles, the Recti, the Obliques and the Levator Palpebra Superioris, spread out over large fields in their insertion. A muscle is only a medium through which nervous motor force is utilized. The two principal kinds of muscular tissue found in the body are voluntary and involuntary. The first are known as striped or striated and get their names from the fact that they are controlled by the will. The second have not the cross-striped appearance, hence are known as unstriped or unstriated. They work automatically, chiefly, hence are classed as involuntary. The muscles of the heart differ in some respects from both of these groups, hence are described as cardiac muscle fibres. As this is a very extensive subject and as histological detail is not essential in this work, it will be reserved for Volume II. CHAPTER XVI. Physiology of the Eyes Utilized to Measure Nerve Supply and Demand. In a bank the first thing a clerk must learn is to know what. constitutes good money. In all other businesses there are equally sound standards; therefore it is natural that the physician should have them. In old school teachings there are standards of temperature, of heart beats, of respiration ; but they are not utilized practically save to employ departures from them as means of frightening patients. To the average physician if the heart skips a beat now and then it is evidence of "mitral valve disease." If respira- tion is too rapid or too slow it is a dreadful pathological symptom. Night sweats mean "tuberculosis" to them ; and afternoon rise in temperature is further "proof." All such stuff is humbug, and, unfortunately, pathetically, the doctor who believes it humbugs himself. We have proved this abun- dantly during the last twenty-five years, by correcting eye defects and other causative factors, when all patients who followed instructions became per- fectly well. Another chapter will go into this matter more thoroughly. We have found in the normal eye a guide to the establishment of stand- ards of measurement of the nerve demand and supply under normal and abnormal conditions. To comprehend it we must know the physiology of the eyes : Nearly all people, including physicians, are under the false impression that good vision means perfect eyes. This is far from the truth, because careful statistics of 10,000 patients and 3,000 students has developed the fact that less than one per cent, of all eyes are really normal ; ninety per cent, are hypermetropic and the balance myopic or blind. Approximately seventy- five per cent, of all hypermetropes have normal vision and of the remainder we have been able to give normal vision to all but about five per cent. The normal, or emmetropic eye, is physically perfect in its refracting qualities and physiologically perfect in its other functions, such as retinal acuteness, rotation of the eye-balls, action of the lids, lacrymation, pupillary adjustability, accomodation, nerve supply and blood circulation. Absolutely normal eyes have their optical axes exactly parallel and rays starting from points on the retinae will pass away from the eyes, after re- fraction, parallel with each axis. The visual axes are identical with the optical axes. The old-school teachings are opposed to this, but we shall prove them wrong by their own figures and by the logic of the situation. First, the alleged "authorities" say that the "visual" axis of each eye 136 A SYSTEM OF MATURE MEDICINE forms an angle with the optic axis of 5 degrees. At 6 meters, which is com- monly called "infinity," the "visual" axis would be 523.5 mm. from the optical axis, because : The distance from the posterior pole of the eye to the optical center is 15.872 mm., which, divided into 6000, (the distance from the optical center to infinity) gives practically 378 to 1 as the ratio of the two conjugate focal distances, hence represent the relative sizes of object and image so located. The distance of the "visual" axis from the optical axis at infinity, representing 5 degrees, is 523.5 mm., because a circle with a radius of 6,000 mm. has a diameter of 12,000 mm. and a circumference of 37,699 mm., which, divided by 360 (degrees) and the quotient multiplied by 5, gives 523.6. Regarding this as the size of the object we divide it by 378 to get the distance, (regarded as the size of the image), from the optical to the "visual" axis at the retina. This division gives 1.385 mm. As the average pupillary distance is 60 mm. we take one-half of it, 30 mm., as the distance from the optic axis of either eye to the median line of the head ; deducting that amount from 523.6 leaves 493.6 mm., from the .median line at 6 meters; then adding 1.3865 to the distance from the optical axis to the median line, 30, we have 31.3865 from the visual axis to the median line at the retina to compare with 493.6 at infinity, which is as 1 is to 15.72. The distance from the retina to the point where the "visual" axis crosses the median line represents one conjugate focal distance and the distance from the crossing point to infinity represents the other one. The first men- tioned is to the second as 1 is to 15.72 ; and dividing the sum of the distances, 6015.872, by the sum of the ratios, 16.72, gives the distance from the retina to the crossing, point on the median line, which is a fraction less than 360 mm. or about 344 mm. from the optical center of the eye, a point approximately 14 inches from the face. This proves the "authority" story is false. Now, taking the 30 mm. from the optic axis to the median line at infinity and dividing it by 378, the ratio between the two conjugate focal distances, we find the distance from the "visual" axis to the optic axis at the retina would be .0793, a trifle less than 8/100 of a millimeter. Inasmuch as the entire macular field is highly sensitized in order to receive images at all, this would be negligible if there really was a "visual" axis. But we shall now see that it is not, because it would not be logical in view of the relation between accommodation and convergence : Six meters is one-sixth of a diopter, and, for an emmetrope to fix on a point at that distance, such an amount of accommodation (adjustment of the crystalline lens) must be em- ployed. As convergence is absolutely necessary for near points and comes automatically with the act of accommodation it would be remarkable indeed if it delayed action while the accommodation worked one-sixth of a diopter; but, worse than that, if the emmetrope wanted to look at a remote distance he would have to exert nerve force through the external recti muscles and diverge the optical axes ! Would any reader be foolish enough to build such an apparatus when he could make it more effective by making the optical and "visual" axes on the same lines? We do not believe you would and we are sure Nature never did such a thing. The optical and visual axes of the eyes being on the same lines and the eyes emmetropic, there is no demand on the nervous system when look- MEASURING NERVE SUPPLY AND DEMAND 137 ing at a distance. To be absolutely exact there would be 1/1584 of a diopter demand for accommodation in each eye and half as much for convergence in each, when fixing on an object a mile away; 3/1584 of a diopter in all; but it is not worth counting. 5 5 V To get a good idea of the mechanism of accommodation let L. Fig. 98, represent a side view of a bicycle tire, c, held in suspension from the outer rim, s s s s s, by the radiating lines, which being elastic but of greater con- tractility than the bicycle tire, keep it stretched to a greater circular diameter than its own elasticity would otherwise permit ; then let the circular lines be connected with the radiating ones and let them represent one continuous line, like a watch spring and be provided with an electric current to wind the spring so that it will pull on the radiating lines lengthening them toward L thus relaxing the tension on the bicycle tire and it is plain that the tire would contract by its own elasticity, so that a bag having spherical curves attached to the tire at its edge would change in shape from L' to L 2 , shown at left. Then let the outer circular line represent the attachment of the suspensory ligaments at the outer edge of the ciliary body, the radiating lines to s s s s s s locate the position of the suspensory ligaments, attached to c, the canal of Petit, and the circular lines indicate the arrangement of the ciliary sphincter muscle, which upon contraction, releases the tension on the bicycle tire, c, and it contracts evenly from all directions, s s s s s s s, thus changing the shape of the crystalline lens from L' to L 2 , at the left, which are edge views of course, A and A representing the line of attachment corre- sponding to to s s s s s s.s in the drawing at the right. By this ingenious arrangement Nature relieves the nervous system of a lot of strain ; the bicycle tire almost overcomes the suspensory ligaments and only needs slight help from the nerves operating the sphincter muscle to increase the lens power. The proofs that this is a correct explanation of the mechanism of accommo- dation are : First, the anatomical arrangement ; second, the fact that a sick child may lose the power of accommodation temporarily from loss of nerve supply, but it is as good as ever on recovery ; third, the decline in accommo- dative power with the arrival of old age is not due to loss of nerve supply because many old people are stronger than they were in youth, hence their loss of accommodation can only be due to loss of elasticity in the tissues of 138 A SYSTEM OF MATURE MEDICINE the suspensory ligaments and bicycle tire, with the result that the resistance of the suspensories is greater and the contractility of the tire is less, and the sphincter nerves and muscles, never having been required to do all of the work refuse to do it and artificial aid must be supplied by lenses for reading. The normal -capacity for changing the power of the crystalline lens ranges from 16.00 diopters at five years to 1.00 diopter at 60 years. The exertion of the full power at any age is exhibited on accommodating to the nearest point possible to maintain clear vision ; this is called the near point, or punctum proximum. With the nerve supply shut off the eye is adapted to its far point or punctum remotum. The distance between these two points is called the range of accommodation and the number of diopters power ex- hibited is the amplitude of accommodation. In establishing a standard of measurement of nerve supply and demand I have proceeded as others did in fixing standards in other business, except that I have followed Natural law while they had to work arbitrarily. I started with the physical fact that a lens of +3.00 power would take rays coming from a point 13 inches away and render them parallel; hence, an emmetropic eye, receiving rays from such a point, which is the usual working distance, would require a -(-3.00 lens to give it the parallel rays for which it is adapted, or it would have to change its crystalline lens approx- imately that amount, because that is the only part of the dioptric system of the eye which is adjustable. Therefore, when an emmetrope reads at any distance we can tell exactly how much work he is doing with each eye in this respect. Fixing on the same object with both eyes necessitates con- stantly increasing convergence as the object is held closer. As the distance from the face is measured in meter-angles, one meter being one meter- angle, half a meter is two meter-angles, one-third meter is three meter- angles, etc., and as these meter-angles are compensated for in diopters we have, respectively one, two and three diopters accommodation in each eye for those distances. We also have one, two and three diopters of con- vergence, with this difference : the two eyes divide the work each turning in half way ; hence the demand for convergence is only one-half as much as for accommodation in each eye for any given distance. Thus, for fixation at one mile the demand would be, for accommodation 1/1584 of a diopter in each eye and 1/1584 of a diopter for convergence in the two eyes, the total demand being 50 per cent greater than the demand for accommodation. For work at the average near point, one-third meter, the ratio is the same : Accommodation }" J'Jjj /K.. o.UO Automatic |L 1.50 Convergence JR. 1.50 Total 9.00 Now, for convenience and comparative calculations a unit of time is necessary to measure the current, so I chose 1 second as the unit and 3 hour? as a day's work; therefore 9x60x60x3 = 97,200 in the three hours of actual close work averaged daily by average people. This all comes from the branches of the third cranial nerves operating MEASURING NERVE SUPPLY AND DEMAND 139 accommodation and convergence only. There are other branches of the same pair of nerves to the superior and inferior recti, the inferior oblique, the levator palpebrae superioris, to the lachrymal apparatus, to the Meibomian ducts and to the tensor tarsi ; then there are the fourth pair to the superior obliques, the sixth pair to the external recti, the second or optic nerve to the retina, all of which receive some nerve supply which we have not been able to measure exactly, but, compared with that we have measured it is so slight that it might be ignored entirely. However, as I need 2800 more units to make an even 100,000 daily demand for the average day's work for an emmetrope I have credited that much to those parts, and as this addition remains in all calculations it is impossible for it to affect the calculation of ratios, which is the object of the standard. The eyes receive their supply through four and one-third pairs of nerves, the latter being the ophthalmic divisions of the fifth, or.trigeminus, the other branches of which go to the upper and lower jaws. The total number of pairs of nerves in the body is 43, of which 12 pairs are cranial and 31 are spinal. Dividing these into ten portions we have an average of approx- imately four and one-third pairs to each portion. Allowing for each sub- division the same amount of energy we have figured for the eye division gives 1,000,000 as representing 100 per cent, daily supply and demand via the nervous system in an ideally perfect person. Now, let us take a hyperope of 1.00, and consider all other parts as nor- mal. In order to see at an infinite distance, that is adapt his eyes to prac- tically parallel rays, he must accommodate 1.00 in each eye; but, as we have seen, the provision for convergence with accommodation is automatic, hence, there is a convergent effort toward a point one meter distant, which, if permitted would cause diplopia, or double vision, therefore the convergent effort must be neutralized while accommodation is continued and the only way this can be done is to exert a negative pull by way of the sixth nerves and external recti to hold the axes on the point accommodation has adapted the dioptric systems to. This involves an extra demand on the nerve supply and it is an especially irritating one, because ordinarily the sixth nerves are only used alternately to turn the eyes outward in looking to the right or left. The total demand is expressed as follows : jL. 1.00 | accommodation j Third Nerves Accommodation ^ T> Automatic (L. .50 i L - JR. I Convergence (R. .50 Sixth Nerves, Negative Pull / \., .OU Total 4.00 As this demand is to overcome an anatomical defect it is continued during all the hours one is awake, an average of sixteen daily. Multiplying 4 by 60 by 60 and 16 we get 230,400 diopters, units, or amperes, as you please, as the extra current demanded daily over the normal 1,000,000 or 23.04 per cent, for each diopter of hyperopia, up to the limit of capacity to overcome such errors, which is about 5.00 diopters. 140 A SYSTEM OF MATURE MEDICINE Anyone can see readily that such a demand must have either an enor- mous reserve to draw upon or work the producing facilities above their normal capacity. Some have a large reserve and continue a long time with- out feeling serious effects ; others begin to feel it early in life. The eyes are the only organs having facilities to conceal their anatomical defects, hence they have a greater influence on the general system than any other part ; and, that influence being exerted insidiously, does lots of damage before the victim seeks help ; then an old school doctor "oculist" is usually called on, who, knowing no more about eyes than his patients do, proceeds to treat the effects instead of removing the cause, with the natural result, failure. This, and the fact that ninety per cent, of all eyes are hyperopic, constitute my reason for saying that the primary cause of eighty-five per cent, of all human ills is nerve strain through the eyes. The manner in which these ills develop is that when the excess current to the eyes is turned on the entire system is increased in voltage, with the result that normal parts receive too much current and the increased tension interferes with their work. It is this tension on the sphincter ani that causes so-called "muscular imbalance" and much of the .constipation, indigestion, piles, "appendicitis," etc. ; on the sphincter uteri it interferes with menstruation, causing at least great pain at the catamenial period and often stops the function completely, devel- oping complications from hysteria to "hasty consumption" or neurasthenia. It interferes with circulation by first increasing vascular tension and finally the insufficient supply to the heart causes it to exhibit weakly even to the skipping of beats. So-called "diseases" of the eyes are nearly all due to uncorrected errors of refraction. They exhibit inflammation, suppuration, granulation and ulceration as the four stages of progress externally; inter- nally, the most common exhibit is cyclitis, or inflammation of the ciliary body, from an injection of the vessels associated with the extra supply of nerve force in overcoming hyperopia; then there are retinal exhibits caused by general systemic affections involving body chemistry and mechanics. No treatment for these .troubles is worth anything if it is not accompanied by correcting glasses. Having the nerve strain caused by 1.00 diopter of hyperopia and having learned how to calculate the strain for any given amount it is only neces- sary to add that, as the accommodation is equally applied to both eyes, if there is a difference in the amounts of error, we figure nerve strain as if both eyes had the same amount of defect and we base our calculation on the fixing eye. It is discovered by having the patient place his finger on the tip of his nose, then point straight away at arm's length, both eyes open, until he thinks he has it directed at your right eye, the left being closed. You note which of his eyes the finger is in line with as you see it. In compound cases the -(- sphere will always represent the amount of error in the most hyperopic meridian, as the prescription comes from the trial frame and we use that as the final basis of our calculation. Thus a hyperope, L.-f-l.oO, R.-J-2.00, R. the fixing eye, would be figured as 2.00 D. hyperopia in each eye; or L.+2.00 .50 axis 180, R.-J-1.50 .75 axis 180, R. the fixing eye would be figured as if it was a case of simple hyperopia of 1.50. Of course in pre- scribing we would give the full correction, with the prescription transposed MEASURING NERVE SUPPLY AND DEMAND 141 to L.-J-1.50+.50 axis 90, R.-f-.T5+.7o axis 90. Or, if a patient is blind in one eye we figure his nerve strain the same as if he had two eyes alike. In myopia there is no nerve strain through excess demand, unless there is an unusual amount of close work, when, by reason of the very near point at which work must be held there may be some excess demand ; but the incoordination between accommodation and convergence and the inability to see well at reasonable distances often causes mental worry which is one of the worst forms of nerve strain. A myope of 3.00 would be able to work at one-third of a meter were it not for the necessity of convergence, which brings with it, automatical accommodation, just as accommodation in hyper- opia brings convergence automatically ; hence such a case, converging to the near point would accommodate approximately 3.00, and this added to his myopia brings his far point, which was originally at one-third meter, up to one-sixth meter, or about 6f inches, requiring still more convergence, but enabling him to see coordinately because the ratio of excess accommodation over convergence could not be maintained above a point farther away and the myopia is substituted for it so that the points of fixation by the dioptric systems and the axial convergence are the same. Myopes should always be slightly under-corrected for distance, that is, do not permit quite normal vision, because there is great danger of over-correction which would create artificial hyperopia, a worse condition than the real thing because it puts a sudden strain on a system entirely unprepared for it. For a similar reason we correct hyperopes in full, that is, we want to save all of the excess demand, and the accommodation resists so we have to apparently overcorrect at first. In other words our first object in prescribing glasses is to relieve the nerve strain of hyperopia; second, to improve vision, when it is below normal with the naked eyes. In cases of myopia the object is to improve vision without causing any nerve strain. On the pages following will be given details with reference to the re- lations of nerve strain through the eyes as causative factors of all sorts of symptoms, from ordinary, dull headaches to periodical sick-headaches ; from simple indigestion to "chronic dyspepsia" ; from stricture of the esophagus to constipation ; from amenorrhoea to menorrhagia ; from a rough skin to psoriasis ; from simple conjunctivitis to "trachoma" ; from dry, itchy eyes to epiphora ; from simple nervous irritation to neurasthenia ; from vertigo to epilepsy ; from tonic spasm to paralysis ; from mental irritability to melan- cholia. The table of accommodation, to be found in the chapter describing the Neurometer, affords some interesting information with reference to that apparatus ; first, it will be noted that between the ages of 5 and 20 years, the decrease in power is 6 diopters, or at the rate of a loss of one diopter every 2% years. From 20 to 30, there is a loss of three diopters, or one diopter every 3% years. From 30 to 40 there is a loss of 2% diopters, or one diopter every 4 years. From 40 to 50 there is a loss of two diopters, or one diopter every five years. From 50 to 60 one and one-half diopters are lost, or a rate of one diopter every 6% years. Thus the loss is more rapid in youth than in old age ; but when we remember that the near point at the age of five years is 2% inches, and at twenty years is 4 inches, we see that the loss A SYSTEM OF MATURE MEDICINE of six diopters only moves the near point from the face 1% inches, while between 40 and 50, with a loss of two diopters, the near point recedes from 9 to 16 inches ; and between 50 and 60, with a loss of 1% diopters, the near point recedes from 16 to 40 inches. In order to make all points as clear as is possible in a book, the same propositions are presented occasionally in different places in different lan- guage. It should be understood by readers that nothing" can take the place of personal instruction, under conditions where the student is at liberty to ask questions freely; that while it is our purpose to give all the information we can, in the simplest language at our command, there are as many different applications of fundamental principles as there are patients in practice ; that the amount of information one gathers from a book is governed largely by the manner in which it is studied ; that superficial reading is all right for a novel, but in learning technical work, each department, even to chapters, should be studied and mastered. If the reader has applied himself to Part I as he should, he will appreciate the coming chapters much better than is possible without an understanding of fundamental principles. The anatomy and physiology of the eye combine the principles of mechanics and chemistry to such a degree that our course in Ophthalmology is the foundation of our general course. We have, almost daily, applications from doctors of other schools of practice who want to take Neurology and skip Ophthalmology, because they "do not care to do eye practice." We refuse all such propositions, because they could not learn the other work without having Ophthalmology first. For the same reasons the student of Ophthalmology must learn Physical Optics first. CHAPTER XVII. . Errors of Refraction in the Dioptric System How They Are Compensated for by Accommodation and with Lenses. Until very recently it was not uncommon to hear the expression "merely fitting glasses," by oculists and physicians in referring to the work of opticians. In one sense they were right ; the average oculist and optician merely fits glasses ; he assumes that any glass he puts on, through which the patient sees as well as without, is a fit. In another sense they were entirely wrong; for there is no major surgical operation requiring as much genuine skill as the correct fitting of a pair of glasses. It is not a job to be done in a few minutes, except in a. very few cases. It cannot be done under an anaesthetic, nor even under the influence of a cycloplegic. There are oculists and opticians or "optometrists" as they call themselves, who pretend to do this work with a mirror (retinascope or skiascope). These fellows differ vitally in their opinions : The oculist, who is a licensed physician, usually without any special knowledge of optics or ophthalmology, says the mirror method works only when the patient is under the effects of atropine ; this is because he is permitted "legally" to use the drug, while the optician is not. The "optometrist" says he can do it without the drug. He has "static" and "dynamic" skiametry, and one "optometry" school advertises that it teaches how to add for reading with the mirror. 1 doubt very much if any of them .ever fitted a pair of glasses correctly. I have proved by many tests, with and without atropine, that the use of the drug is a mistake. I have found that those who employ it do not know how to tell when a patient is completely under its influence ; they know little mechanical ophthalmology and they rely on what their preceptors have told them. Often, after the pupils dilated and accommodation appeared weak, I have found by physio- logical tests that it was easily excited, hence would deceive any but one who knew how to make the tests ; it is therefore unreliable. As to the claims of those who do objective testing, it makes them ridiculous, because it does not even work subjectively, where we have auxiliary means of holding the nervous system in check, and working with the mirror is always an irritation. The method of procedure I propose to describe does not require or permit the use of drugs ; indeed we could not complete our work under such con- ditions, nor secure any proofs that our procedure is effective. The oculist assumes that because he does the work it must be correct, because he is following "authorities" ; the optician imitates the oculist as far as he can. 144 A SYSTEM OF MATURE MEDICINE We have methods of proving every step in our work, whether it be physical, physiological, temperamental or therapeutic. The others do not believe such things possible, and refuse to investigate. To do a thorough job of fitting glasses, the operator must know : First, the physical laws governing the matter; second, he must be well trained in physiology and the mechanism of the accommodation and convergence apparatus; he must know anatomy, symptomatology, dynamic and static tests and what they mean under all sorts of general conditions ; he must have anticipated many situations and have decided what he would do if he ever met them. To illustrate : About fifteen years ago an elderly man came to my office and asked me what I could do for a peculiar condition he ex- hibited, namely, he had lost not only his power of accommodation for near points but his ability to converge the axes of his eyes for near points was gone, so that even with added power of lenses for near work he could not do it for more than a minute, when he saw double. I told him I could fix it in a minute. He doubted, of course, because he had just come from the then "greatest" oculist in Chicago, and he asked how many cases like his T had handled. I replied: "I never saw one before." He was evidently dis- appointed and wanted to know how I knew I could fix it. I told him I knew the law, because I had anticipated such a case and had it all figured out. Then I proceeded to place a five-degree prism, base in, before each eye, in combination with his glasses for near .work. The job was done. He sat in the office for two hours, reading the morning paper with comfort for the first time in months. I took the scales off his distance lenses and gave him a prescription for grab fronts containing his reading correction in combina- tion with the prisms. I informed him that if his power of convergence returned, which was possible, all he would have to do would be to have the reading glasses made without the prisms. He lived several years and never had to change them. I have never seen another case and scarcely expect to. It is the only time I ever prescribed prisms, and it was not done to treat the case other than as giving an artificial leg to replace a missing one would be treatment. No other sort of case will ever need a prism. See chapter on prisms. The true ophthalmologist must take into account many other condi- tions beside eye defects, because if he does not, even if he could correct the errors, he could not hope for good results in more than a small per cent, of his cases. We take careful notes on the appearance and the history of each case; make an ophthalmoscopic examination to find systemic conditions; employ tests of vision, accommodation, with and without glasses, static tests, and record each item carefully to be used in analyzing the case. All of these essentials are absolutely unknown to the oculist and optician. They cer- tainly "merely fit glasses," if we stretch a point and admit the "fit," which is a farce. If their methods constitute a system of special practice our Ophthalmology is a system of general practice. It is very doubtful if one in a hundred of them could measure the test letters they use and assure themselves of the correctness of the sizes. Very few of the test charts are correct and every practitioner should know how to measure them. A one-minute angle is the smallest that a normal eye ERRORS OF REFRACTION 145 can utilize for visual purposes, as has been proved by repeated tests by skillful men. Test letters are made on a five-minute basis because the hori- zontal lines in the letter E, for example, are three in number and the spaces between them, two, being" of equal width, each representing a one- minute angle, constitutes a standard of five minutes. To find the size of type for any distance : Take the distance as the radius of a circle ; multiply its diameter by 3.1416; divide by 360 degrees; divide by 60 minutes; multiply by 5 minutes. Thus, the usual working distance is 20 feet, or 6 meters ; the latter equals 6,000 millimeters as the radius of the circle ; doubling it gives the diameter, 12,000 millimeters ; multiplying this by 3.1416 gives the cir- cumference of the circle at 37,699.2 millimeters; dividing this by 360 gives the number of millimeters per degree, 104.44; dividing this by 60 gives the millimeters per minute, 1.74; multiplying this by 5 gives the size of the space occupied by a correct test letter, 8.7 millimeters. The reason I have reduced the figures to one minute is that it enables me to tell quickly the error in a letter which measures wrongly. On many cards the six-meter letters measure 10 millimeters; and this, divided by 1.74, gives an angle of 5.7471 minutes, or 5' 42". A short way to get the five-minute angle, is to divide the circumference of the circle by 4320 ; this is because the five-minute angle is one-twelfth of 60, therefore multiplying 360 by 12 gives 4320, the number of five-minute angles in any circle. In Chapter XII the proportions of the normal eye are given and refer- ence is made to defective ones. In the first paragraphs of this chapter the "mere" method of fitting glasses is mentioned unfavorably. Let us now pro- ceed to examine the matter in detail : In Fig. 99 we have an emmetropic eye, adapted to parallel rays R R, which are focused on the retina at the posterior pole of the eye, without any effort whatever. Also the rays divergent from F are focused at the same place, provided the mechanism of accommodation changes the surfaces of the lens to the positions of the dotted lines. Of course no one will under- stand that an eye can adapt itself to two positions at once. When it is in its static, or natural condition it is adapted to the parallel rays; when its dynamics are applied to the lens it is increased in power and is holding the retina in conjugate focus with F. The particular point to be made is that accommodation always makes the lens more convex and withdrawing the nerve impulse only permits the surfaces of the lens to resume their natural relation. There is no capacity for making the lens of less power than it has naturally. When an emmetrope exhibits his maximum power of accommo- dation he fixes on his near point, or "punctum proximum," as would-be impressive doctors call it ; the effort is called his amplitude of accommodation and is expressed in diopters ; the range of accommodation is the distance be- tween this near point and infinity, which is his far point, or "punctum re- motum," as the aforesaid would-be calls it. 146 A SYSTEM OF MATURE MEDICINE fa. /Off Fig 100 shows a hypermetropic eye ; without accommodation the principal focal point is at F behind the posterior pole ; with accommodation, as shown by the dotted lines at the lens surfaces, the focus is at the posterior pole. This accommodative effort is necessary in order to enable such an eye to see well. Ninety per cent, of all people are hypermetropic, more or less. All such form the habit of accommodating and develop extra strong muscles and nerves in that department. Of course when the defect is great the excess demand on the general nerve supply tends to weaken the whole system rapidly and other functions become involved ; incidentally the accommodative power lessens, and after a time the entire error cannot be overcome, hence vision is affected. When -\- lenses are accepted readily, with good vision, the power of the strongest lens so accepted is the measure of the manifest hyper- metropia; when stronger lenses can be forced on by any process and vision become normal after wearing them for a few weeks, the difference between the stronger and weaker lenses is the measure of the latent hypermetropia, or that which was concealed by the active accommodation. Many people, par- ticularly those under mature age, conceal all of their hypermetropia, yet ex- hibit general disturbances which tell the ophthalmologist that the eye defect exists. It is our business to make the total amount of the error manifest. This takes time, because of the habit of constant accommodation ; to make it manifest with a cycloplegic would not be satisfactory, because as soon as the effects of the drug wear away, as they do in a few days, any glasses found while the accommodation was paralyzed would not give vision and would not be worn by the patient. There have been many foolish notions exploited by writers on the subject. Some advocate for children one-fourth of the full correction found under atropine ; for young adults, one-half, and for older ones, three-fourths. That sort of practice would never accomplish anything for those suffering from general physiological disturbances, because of their eye strain, for the reason that the eye strain would not be removed. All it would do would be to make a partial saving and give good vision. By our method of procedure, we get good vision in a few weeks and insure full benefit to the general condition by our auxiliary methods of handling cases ; so that our ophthalmology is, really, a system of general practice. Fig. 101 shows how the hypermetropic eye sees perfectly with the cor- recting lens after we have induced the permanent relaxation of the nerve tension on the lens, so that it remains in its static condition, except when it is necessary to accommodate for near points, as in Fig. 99. A fantastic idea of ERRORS OF REFRACTION 147 oculist authors is that, if the error is corrected in full it will cause atrophy of the accommodation from non-use. Any novice ought to be able to see that emmetropes do not exhibit atrophy, and .we have only made the hyperme- trope an emmetrope. As a matter of fact, after a hypermetrope has been corrected at a reasonable age, he is the last to exhibit the presbyopic condi- tion incident to old age ; this is because "his department of accommodation was developed above normal before we corrected the error, and under nor- mal conditions he naturally holds out longer without assistance for reading than any other class, emmetropic or myopic. The common name for Hyper- metropia is far-sight, but it is only true in the sense that his nervous system is irritated until vision is a little keener than normal. Fig. 102 shows a myopic eye, with the parallel rays, R. R., focusing in front of the retina because of the excessive power of the static dioptric system. Accommodation would only make the focus shorter and the resulting circle of diffusion at the retina larger, hence the only way such an eye can be ad- justed so the retina will be in conjugate focus with the object is to bring the object to F, when there will be sufficient divergence to the approaching rays to put the focus back to the retina as shown. For nearer points the myope must accommodate, of course. The common name for myopia is near-sight. It will be seen readily that myopia is always manifest; the only possibility is that one who is doing much near work might exhibit some spasm of accommodation and manifest more myopia than really exists. There could not be any possibility of latent myopia, as anyone with a little optical education can see readily. Yet there are alleged "teachers" of optics running at large who assert latent myopia is common. They also teach that if a myopic patient sees as well with a 3.00 as with a -- 2.00 the 3.00 is the lens to prescribe. Anyone, even a fool, ought to see that the extra 1.00 would create an artificial hypermetropia and cause trouble as sure as there is such a thing. Such "teachers" are of the class who fit glasses with mir- rors and machines. This modest book is so much Greek to them. Fig. 103 shows how a lens takes the rays R R and sends them to the eye as if they came from F thus enabling the dioptric system to focus them at the retina so the wearer can see at a distance. Great care must be taken to not make the lens too strong or it will create artificial hyperopia and cause nerve strain. In the course of our work we classify our cases many times : 148 First, as good, fair, medium or bad, in appearance, with reference to health, development, proportions, temperament, disposition, mental balance, physiognomy, social status, etc. All opinions are subject to alterations in the final analysis, because we have learned to not believe our own eyes, ears, or other senses without corroborative evidence. No true ophthal- mologist forms conclusions upon which he acts until analysis develops proofs. Second, family history and details of each case are necessary to establish or refute what the appearance tells us. After hearing a patient's story we cross-question to bring out all of the facts. Sometimes one merely repeats what he has evidently been told by some doctor who failed on his case and even made it worse for us by leaving bad mental impressions. It is this that taught us the fact that the mentality is always in as bad condition as the physiology of the body, if not worse. The other fact that people grow angry when told that such is the case is what proves the truth of the first proposition. Third, the ophthalmoscopic examination tells us the number and calibre of the vessels in all cases, gives us a general knowledge of the circulatory system throughout the body, the quality and quantity of blood in the arteries and veins, and discloses any local features which may chance to exist to offer possible interference with our work ; sometimes telling of congenital causes of conditions which may cost the vision of the patient ; in other cases we find evidence of systemic changes, which, if not arrested, will cause serious complications. As a means of measuring the errors of refrac- tion the ophthalmoscope is of no use whatever. We may, incidentally, recognize high amounts of hypermetropia or myopia, but that is all. There are people who pretend to fit eyes with the ophthalmoscope ; but they are deliberate liars; a statement which I stand ready to prove. Fourth, by a series of dynamic and static tests we measure the nerve supply as well as the eye defects and the auxiliary causes of the ills ex- hibited, and by our final analysis, from the data obtained, we find the High, Safety, Danger and Low lines of each patient ; and, if we take the case, we stipulate just what Nature demands the patient must do to get good re- sults, knowing what we must do at every stage of the proceedurc, even to what charges to make for our services, which fees are collected in advance that we may have a guarantee the patient will do what is required and not disgrace our system of practice by dishonest conduct. We know the laws will work if given fair opportunities, and we know sick people are weak in will power, hence are unreliable. After the preliminary examination, which includes an examination of the ears, nose, mouth, teeth, heart, lungs, etc., we proceed with the detailed eye examination, which, with us, is a general test of the nervous system. The vision test means much to one who understands its classification. First, normal vision does not mean normal eyes, but it tells us there is very little if any astigmatism ; there may be lots of hypermetropia. Second, better than normal vision, say 20/15, is proof there is no astig- matism worth correcting, and that there is at least 1.00 D. hyperopia. Third, less than normal vision simply indicates that fact ; it may be hyperopia without accommodation ; it may be astigmatism ; it may be myopia ERRORS OF REFRACTION 149 and may be an affection of the optic nerve or the media through which light passes to reach the retina. Fourth, the same vision in the two eyes does not prove they are alike in their refractive conditions. The dynamic test also has its classifications : First, those under approximately 20 years should show at least 12.00 D. accommodation without glasses, and after correction of hyperopia should show less than at the first test; not because they have less, because we know they have the amount of the correcting lens more than they showed at the first test, but because of the nearness of the near point at the first test and the prismatic effect of the -f- lenses at the second test they should not equal the first showing. If they do equal or exceed it we take it as a symp- tom of weakness and act accordingly in prescribing. Second, those between approximately 20 and 35 years should show ex- actly as much increase at the second test as the correcting -)- lens amounts to. They should show at the first test not less than the amount indicated for that class in the Neurometer. (See chapter on the Neurometer). Third, those between 35 and 50 years should show considerable increase at the second test, even to three times the amount of the + sphere in the correction, if it is comparatively weak, and twice as much if it is strong. Fourth, those over 50 are often presbyopic and" cannot register at the first test ; but they will usually register after correction. If they do not we add for reading and then make the test getting the maximum power indicated by the near point from which is to be deducted the amount of the lens added for reading, the remainder being the dynamic showing. Anyone who exhibits the symptoms of a person of a younger class is giving evidence of nervous irritation ; and any who exhibits the symptoms of an older class than that to which he evidently belongs, is certainly below normal in nerve supply. The static test also has its classifications : First, with the red glass on the right eye and the Maddox double-prism on the left, in such a position that the patient sees two lights in a vertical position at a distance of fifteen or twenty feet, where only one exists, we un- cover the right eye, when three lights should be seen in a vertical line, with the red one exactly midway between the two white ones. If it is seen there it is orthophoria, that is the eyes are in balance. If the red light is not in that position it is heterophoria, a tending out of balance. This only exhibits under the test, when the eyes are practically thrown out of gear. This test may be made with the Maddox rod over one eye, but it is uncertain be- cause if the patient turns his head it will deceive the operator ; and, it has to be placed in two different positions, vertical and horizontal, to complete the test. Second, if the red light is seen to the left, the axes are tending toward each other because of a nervous spasm exhibiting through the third nerves and the internal recti ; if it deviates up or down, as well as to the left, it merely indicates that the spasm is erratic. As a whole it means that there is a spasm of accommodation, not only in the eyes but all over the body; such cases will have constipation, bladder trouble, womb troubles, and other 150 A SYSTEM OF MATURE MEDICINE evidences of tonic spasm. We call this the -|- impulse, and if it remains after the refraction test we know we have to take time to conquer that spasm, so we give temporary lenses and order rest, baths and anything else that will conduce to general relaxation. The lenses should blur vision con- siderably, too. Say to 20/80, and the patient must not look over or around them. He is temporarily nearsighted. He can see well if he gets near enough the objects. They cannot possibly do harm. They sometimes frighten patients who do not understand what is being done and they work themselves into worse spasms, which irritate and inflame the eyes, but a repetition of instructions will suffice to get people of intelligence to follow instructions and they will always come out all right. Third, if the red light appears to the right it is the impulse and means the nervous system is weak, exhibiting through the same channels as before, namely, the third nerves and the internal recti. If the deviation is upward or downward as well as outward it simply means the weakness is erratic and intermittent. Temporary lenses and rest will do such cases no harm and results will come quicker and better by taking time to the case. Fourth, If the red light deviates up or down and neither to the right or left, it indicates a doubtful tendency ; another day it might show to the right or left. We handle it as if it were a -(- impulse, to be on the safe side. All of these deviations are merely symptoms of the nervous status and never indicate muscle weakness or strength. Whoever says it does would better study anatomy and physiology and learn that muscles are only mediums through which nerve force is applied; that there is no such thing as a weak or strong muscle ; that to treat such cases with prisms is a crime and to operate on the muscles is a double crime. Having finished these tests and made notations for reference both while making the refraction test and in completing the analysis, we proceed to put on -f spherical lenses, settling on the strongest + sphere the patient can see the 200 type dimly with. This tells us something important : A + 1.50 will fog an emmetrope to 20/200, hence if a hyperope can see that well with a + 3.00 he must have at least 1.50 hyperopia ; in other words, after finding the strongest -f- sphere with which a patient can read 20/200, deduct 1.50 and you have the minimum hyperopia. There may be more, but never less. That bit of information is worth the cost of the book, no matter what you paid for it. In reducing fogging lenses it must be done deliberately and with skill or the nervous system will be irritated and the accommodation will act vig- orously. Here is where knowing the value of the test card comes in. Re- member the patient is not under an anaesthetic and when you have found that .25 or .50 brings the 200 line clear and the next line dimly you must know the value of the distance between the first and second line ; also the value of the differences between all of the other lines ; then, following the principle all the way down the card, you will know at once when the ac- commodation is beginning to act against the unfogging. If - - .50 brings vision from 200 to 120, that is 80 feet, theoretically, the next distance, to line 80, is forty feet and an additional - - .25 should bring that line into view, but, as we start at 200, there is an element of uncertainty in the amount that ERRORS OF REFRACTION 151 brings the second line clear, and we can only be certain by having the patient read aloud and as soon as a line appears dimly have him try to read it; if he misses no letters it is counted, and so on down two or three lines, when we are sure we have his accommodation in control or have positive evidence we have not. Then we simply prescribe temporary -|- spheres and have them worn several days to break down the spasm and build up the nerve supply by rest. Unfogging must be done deliberately and with skill. Sometimes it is good policy to come back with two lenses of the same power, say 75 and - .75, after having tried weaker ones and shown the patient that vision is always better with the second lens at each trial. I have taken cases from 20/80 to 20/30 with the same lenses, pretending; to change them but coming back with the same ones several times. This has to be done diplomatically or it may arouse suspicion and antagonism, unconsciously, of course. Never reduce the vision to a point better than the exhibit with the naked eye until after you have changed the fogging lens for one representing the -f- diff- erence between it and the unfogging lens and have made search for astigma- tism, when, if none is found, leave that eye and take the other through the same process. Then if vision is not normal with the two eyes it may be necessary to reduce the spheres. If vision was normal at first never reduce to 'better than 20/30 in the unfogging; and if it was as bad as 20/60 do not reduce below that point until you have eliminated the astigmatism. There are so many little details about the fitting process that it is practically im- possible to give them all except in clinical demonstrations during personal instruction. If -f- lenses will not be accepted and we find no evidence of nervous spasm, we use the stenopaic disk, or the slot, to find if there is any meridian at which vision is better than at others. If there is one we make a note of its acuteness of vision, then reverse the slot, that is put it at right angles with the first position and hold spheres in front, increasing them if neces- sary until that meridian sees as well as the other did without a lens. Then we put on a cylinder, axis on the good meridian, removing the slot. If vision is not normal with it, spheres may be added, always using the weakest possible to get the desired improvement in vision; as a rule do not give myopes better than 20/30 vision unless they are old people whose ac- commodation is not liable to deceive you. If -f- spheres are accepted and the search, for astigmatism is to be made, do it in the manner prescribed in the preceding paragraph, because your patient is an artificial myope with your -j- sphere on. Never permit a patient to make comments during the test ; require him to read the smallest letters he can at each change of lenses ; have him read aloud, that is not second-hand information, in legal parlance. You know what you want. He does not. Therefore stick to your plan of work and insist that patients do as told. Use 8-point Roman type in making all dynamic tests, because the Neuro- meter is based on that. In testing young people have them hold the paper as close to the face as possible ; then slowly push, away and begin reading aloud as soon as they can see clearly, stopping at that point. Measure it 152 A SYSTEM OF MATURE MEDICINE in inches or centimeters and express in diopters. For mature people, say of 30 years or over, have test paper held at the usual reading point and then drawn to the nearest point at which they read aloud dimly. Take measure as before and express in diopters. Occasionally there is a case of nervous ir- ritation in people over 30 where it is necessary to proceed as with the young- er class in order to secure a reasonable registration. Fig. 104 illustrates an astigmatic chart in common use. It is usually made suitable to the 6 meter distance, 'and should conform to the measure of the lines on the letter chart for that distance. It is extremely un- reliable : One without a particle of astig- matism may see the vertical lines much the plainest because of the habit of looking at vertical objects has developed retinal sen- sibility in that meridian over the others ; Another with considerable astigmatism may see no difference in the appearance of the lines. The test with the slot and letters is the best of all ; but there are people who cannot use it. Then cylinders must be used, and, after it is found they will give more visual improvement than spheres, the weakest one which will give the desired improvement must be used. My method of proving a cylinder is to first hold in front of the complete correction a + .25 cylinder ; if it improves vision I weaken the cylinder in the correction ; (by the proceedure described as the fitting process I always have cylinders in the trial frame); if it is worse I offer .25 -- cylinder; if that improves vision I compare the -- cylinder with a -- .25 sphere, if the sphere is best the cylinder is proved ; if not I increase the cylinder .25 and repeat the prov- ing test. If the final cylinder is as weak as .50, even if I have proved it, I sometimes remove it for a minute, then compare it with a - - .25 sphere and if patient says the sphere is best I steal the cylinder and befriend my patient. Sometimes, if vision is good and the same with each eye, I fog and unfog both eyes at once, in order to save time. Of course when the astig- matism hunt is on I have to take, each eye separately. After completing the refraction test and proving it as far as possible at that stage, the dynamic and .static tests are repeated and the data recorded for later use, as described in the chapter on the Neurometer. To put, the entire story, of the procedure of fitting glasses, so far as the refraction test goes, into the smallest space possible we have the following: Look for: First, -|- spheres; the strongest the patient can see almost as well with as without. Second, cylinders ; the weakest that will ac- complish the purpose of improving vision. Third, -spheres; the weakest that will give the vision desired. Possible results : First, a + sphere alone, indicating simple hyperopia. Second, a -f- sphere and a cylinder, the first to save nerve strain and the second to improve vision ; indicating simple hyperopic astigmatism, if the cylinder is of the same power as the sphere ; compound hyperopic astig- ERRORS OF REFRACTION matism, if the cylinder is of less power than the sphere; mixed astigmatism, if the cylinder is stronger than the sphere. Third, a -- cylinder alone, in- dicating simple myopic astigmatism. Fourth, a cylinder combined with a - sphere, indicating compound myopic astigmatism. Fifth, a - - sphere alpne, indicating simple myopia. The second of the possible results is the only prescription that ever needs transposing and never needs it if the cylinder is more than twice as strong as the -f- sphere. This is a purely physical proposition; as a physiological one we often do transpose them when the cylinder is" more than twice as strong as the sphere, but we always have abundant reason for such proceedure. Never use cylinders in temporary lenses except where there is so much astigmatism that there is amblyopia and the cylinder is put in to improve that condition. Temporary lenses are employed to break down spasms, to build up weakened systems in connection with rest, sleep, baths, wholesome food, etc. \Yhen we have completed one examination we usually have sufficient data to make an analysis ; if we have not we order rest and return for further examination. Some writers, in fact nearly all of them, have advised against correcting anisometropia, (differences of error in the two eyes), and particularly against correcting it for reading, giving as a reason that it makes patients dizzy and uncomfortable generally. They have also made the same statement with reference to oblique astigmatism, saying "patients will not tolerate such cor- rections." This is all nonsense. I began killing their idols, 25 years ago, and have never had a single failure, because I know the reason for the alleged intolerance ; that it was not like the intolerance of drugs, which are poisonous; that it was merely a matter of readjustment of the nervous sys- tem, which might be termed another form of accommodation. I have always given full corrections, explained to patients the various things likely to happen, from a trifling inconvenience to pain in the eyes, dizziness, and even sea-sickness ; but I always assured them that if they would persist in wear- ing their glasses, the effects would soon pass away, and they would be delighted ; that if they looked over their glasses, or took them off, it might take months to become adjusted, while, by following instructions, they would be all right in two or three weeks. Nearly all did as directed, and the results were as promised. Even those who did not follow instructions came around all right eventually. Eyes without glasses become presbyopic in the following order: hyper- opes first; ametropes next, and myopes last. This refers only to the wearing of -f- lenses for reading; the myope has less accommodation than the emme- trope of the same age, but his myopia does much of the reading work for him, so that he rarely needs lenses at all, and never unless his myopia is less than about two diopters. If the ametropia be corrected as early as 25 or 30 years of age, the order of presbyopia' changes. The myope comes first, the 15-i A SYSTEM OF MATURE MEDICINE emmetrope second, and the hyperope last. The reason for this is that in over- coming his hyperopia with his accommodation, the ciliary muscle and nerve supply becomes stronger than normal, just as any other part becomes stronger from extraordinary use, and he retains this excess development for near work after being relieved of the distance strain. Much has been written about spasm of accommodation, the varieties described being almost as numerous as the writers. As a matter of fact, there are but two kinds : One is the spasm of the vigor of youth ; and this is present often even in sickly children, so that we would better say the vigor of the youthful eye ; this is always so strong that unless the operator is thoroughly conversant with possible conditions and causes, that is, knows thoroughly the physics and physiology involved, he will often fail to get good results in nervous disorders, and will assume that there must be obscure contributing causes, when he has not found nearly the full amount of hyperopia. The other form is the spasm produced in older people by the continued effort of accommodation in overcoming hyperopia and doing a lot of near work in addition. This variety is also found in the very young if they have much hyperopia, and it is practically the sole cause of strabismus, which is described in another chapter. In either of the varieties mentioned, the spasm may be clonic or tonic. The first may be normal, that is, not pathological ; but this is the case only in young children. The second is always pathological, because it means the nervous system is so intensely irritated that it cramps; indeed it is often indicated by pain in the eye- balls some writers have denominated this "rheumatism of the eyes." We have referred to this feature in the chapter on alleged "diseases" of the eyes. There is no sharp line of demarcation between clonic and tonic spasms, be- cause they are like the colors of the spectrum, they blend together; some clonic cases will develop a tonic condition while we work on them, and some tonic spasms will break down to the extent that they become clonic while we work. The use of atropine, or other cyclopegic, is not only of no value in our method of practice, but they cause inconvenience to the patients, and would actually interfere with our analysis of our cases. CHAPTER XVIII. The Neurometric Method of Analysis of Conditions Found by Examinations. The Neurometer (nerve measure) is a product of Natural laws, sup- ported by years of careful application of the principles, proved by statistics from clinical records. It is most useful in practice because we are not only able to analyze each case so that we do not prescribe by diagnosis, but we find the Natural resources of patients, make certain prognoses and fix the fee in each instance. Having found positively what Nature can do if given the opportunity it is then up to the patient to follow instructions and we collect our fees in advance as a guaranty against disobedience and the in- fluences of "meddlesome Matties." Some things can be figured theoretically and some are found only through the developments in practice; hence, Theory and Practice are the two legs we stand on professionally, and to make them equally good each must support the other. Theoretically, youth is physiologically more elastic than age. Practi- cally, persons under about twenty years, in average good condition, show less accommodation after correction of hyperopia than before. Of course we know that in making the first registration of accommodative power the effort includes overcoming the error if it is hyperopia, which does not .ex- hibit in the registration, and we add that amount to the first showing to get the total dynamic capacity. There are two reasons for the exhibit of this class : First, the nerve supply is so great that they can accommodate to the limit of capacity for convergence before correction ; second, in making the second test, with lenses on, there are the effects of prisms bases out, so that there is more convergence and accommodation being done than is indicated by the distance the card is held from the face, because the rays are broken outward by the inner halves of the -f- lenses and appear to come from a point much nearer, the distance being regulated to some extent by the dioptric power of the lenses. When we add the amount of error to the first registration, we have taken care of that point, and only need to remember that this is the standard status of this class and when anyone shows more accommodation after correction than the first showing, plus the amount of hyperopia, the whole is an indication of weakness and the dynamic symptom is marked "bad." Between the ages of 20 and 35 years the average good condition exhibits dynamically by showing an increase at the second registration over the 156 A SYSTEM OF MATURE MEDICINE first of exactly the amount of the hyperopia. If any patient shows less in- crease than this it is an indication of nervous irritation which caused too great a showing at the first test ; and if one shows greater increase than the amount of the hyperopia it is evidence of weakness, too small a showing, at first test. Between 35 and 50 years is a period of variations. During the first half of this period the showing at the second dynamic test will be from two to four times the amount of hyperopia increase over the first showing; but during the last half of the period this will be reduced until, sometimes, when there is a great error, there will be no registration at the first test and we have to accept the second test at its face value ; or, if there is a register at the first test the increase will only be equal to the amount of hyperopia, or a little more, at the second test. After 50 or thereabouts, if there is much hyperopia the first test will give no registration because the accommodation is so weakened that it can- not register near points ; and, sometimes, there will be no .registration at the second test, proving great weakness ; but the weakness is not nervous deficiency, it is from loss of elasticity in the suspensory ligaments and bicycle tire the loss of accommodation incident to old age, which is called pres- byobia'. In these instances we add -(- 3.00 to the distance correction and then require the patient to register. Taking his near point we express it in diopters and deduct the 3.00 we gave when the remainder is the dynamic showing. Recapitulating, we have in the foregoing the standard in each of the four classes ; therefore, when, by the dynamic test any case registers in a younger class than is actually true it is an indication of an irritated nervous system ; and if one registers in an older class than is really true, it means nervous weakness. Also, if the effort of accommodation causes pain in the eye-balls it is an indication of irritation and if it causes nausea it is an evidence of great weakness of the nerve supply. As a theoretical standard of accommodation for normal eyes, doing a nor- mal amount of work, an average of three hours daily at approximately 13 inches, at different ages, Table 1 is submitted with the explanation that the age figures are the bases made for dynamic tests, to which are added certain amounts in years, months and days, for physiological strain and mental temperament, after which deductions are made for symptoms exhibited in the several tests. It is a significant fact that in utilizing the Neurometer practically we have found that we cannot add anything for temperament in cases under approximately 20 years of age. This is not because they lack intelligence or common sense ; it is because they have not yet arrived at the point where these factors are working to any great extent, being smothered by love of frivolities and ego children always think their elders arc old fogies who cannot appreciate modern conditions, when, as matters of fact, the older ones have been all around the same old circle. The weakness of the older ones is they are fanatically intolerant and that only works against their influence with the younger ones. When I get in such condition I am unable to show the young ones tricks I'll hang my harp on a weeping willow tree and hie NEUROMETRIC METHOD OF ANALYSIS 157 me to a hermitage. My influence with the young is that I encourage their "foolishness" but take the conceit out of them by telling them I have been worse than they are, and proving it. Then they come to me for pointers and I utilize my opportunities to get them interested in real, natural, rational things which help them to grow, mentally and physically. TABLE 1. Nea Poi] 2f 3 4 .r at. in. in. . . . , Diopters. 16.00... 14.00. . . Years. 5 10 Age. Months. Days. 0.. ()-. in ....... 13.00... ,. 1200 . 12 15 6. 0. 0.. 0.. in in . . . , 11.00... , 10 00. . . 17 20 6. 0. 0.. 0.. 4 5 6 6|- in. . . . . . ., 9.00. . . 23 4. .0. . in. . . . 8.50. . . 25 ..... 0. . in. 8.00. . . 26 . . .. 8. 0.. in. 7.50... 28 4. 0.. in. in. , 7.00... 6.75. . . 30 31 0. 0. 0.. 0.. in. . . . , 6.50. . . 32 0. o. . in . . ' 6 25 ... 33 . . 0. . in. ... in. . . . 6.00... 5.75. . . 34 35 ...0. 0. 0.. 0.. 7 71 8 9 10 11 12 13 14 15 16 in. . . . 5.50. . . 36 0. 0.. in. in. . . . 5.25... 5.00. .. 37 38 0. 0. 0.. 0.. in 4.75. . . 39 . . .0. 0.. in 450. .. 40 0. 0.. in .425.. 41 . . .3. 0. . in. in 4.00... 3.75... . . 3 50 42 43 45 .. 6. 9. 0. 0.. 0.. 0.. . 3 25 . 46 . . .3. 0.. in ... . 3 00 47. . 6. 0.. 2 75 48 . . . 9 .. 0.. in. ... . .., 2.63... 2 50 49 50 4. 0. 15.. 0.. 18 20 22 26 32 40 in. 2.25... 2 00 51 53 8. 4. 0.. 0.. 1 75 0. 0.. 1 50 56 . . .8. 0.. in. ... in. 1.25. .. , 1.00.. : 58 60 4. 0. 0.. 0.. 158 A SYSTEM OF MATURE MEDICINE TABLE 2. If our patient is an emmetrope but works extra hours over the average three upon which this table is based, we would add to his showing by the dynamic test: For 6 hours extra, 10 years, months. For 5 hours extra, 8 years, 4 months. For 4 hours extra, 6 years, 8 months. For 3 hours extra, 5 years, months. For 2 hours extra, 3 years, 4 months. For 1 hour extra, 1 year, 8 months. TABLE 3 A. All calculations where hyperopic errors -of refraction exist must include an item from the following table with variations, unless especially exempted : ADDITIONS FOR HYPEROPIA. For 1.00 D. add 10 . . .0. . For .75 or 1.25 add 8 . . .9. . For .50 or 1.50 add i 7. . . . .6. . For 1.75 add 6 .. .3. . () For 2.00 add 5 . . .0. . For 2.25 add 4 . 7. For 2.50 add 4 . . .2. . For 2.75 add 3 . . . 9 . . For 3.00 add 3 .. .4. . For 3.25 add 3 . . .0 . 20 For 3.50 add 2 . . .9 10 For 4.00 add 2 . . .6. . For 4.50 add 2 . . .3. . For 5 00 add 2 . . .0. . This table is subject to alterations for conditions found by the examina- tions and tests : TABLE 3 B. If the patient is a hyperope and is working extra hours, too, it is evidently just that much worse for him, so we figure the extra hours equal to more error, thus : 6 hours extra equals 1.00 D. more hyperopia. 5 hours extra equals .75 D. more hyperopia. . 4 hours extra equals .75 D. more hyperopia. 3 hours extra equals .50 D. more hyperopia. 2 hours extra equals .50 D. more hyperopia. 1 hour extra equals .25 D. more hyperopia. If the hyperopia has been corrected in full for a year or more and the error is less than 1.50, we add to Table 1 exhibit for extra work only, as if the case was emmetropic. See Table 2. If the error is more than 1.50 add for NEUROMETRIC METHOD OF ANALYSIS 159 the hypermetropia, even if it has been corrected in full, then add for the extra work as per Table 2. If the hyperopia has been partly corrected add for the uncorrected error, Table 3A, plus the extra work, Table 3B. If a patient has been wearing lenses when -f- were needed there is an artificial hyperopia to be added to the real, so we add for the sum per Table 3A; and, if there is extra work, we include it as per Table 3B. If the dynamic test in any case, with the correcting glasses on, does not show a registration of at least as much more than at the first test as the -(- sphere represents we add that much to the first showing, because the pa- tient must have that much more to overcome the error before beginning work for a near point. If the second test shows more increase than the correc- tion amounts to we accept it because the patient must have it or he could not show it, after being made emmetropic with lenses. If the static test shows a + impulse after correction to normal vision with the strongest -f~ spheres we can force on, we add to the power of the spheres regardless of the vision it gives, because we know there is a spasm of the entire nervous system and that it is exhibiting through the third nerves to the internal recti muscles and of course involves the accommoda- tion. If the + impulse is anywhere from 1 to 3 degrees we add -f- .50 to the spheres ; if it is 4 to 6 degrees we add -f- .75 ; if it is 7 to 10 degrees we add -f 1.00; if from 11 to 14 degrees we add -f 1.50; if more than 14 degrees we add +2.00. The relation between the dynamic and static tests is a most valuable one, because one is a voluntary exhibit and the other is involuntary ; in the first we require the patient to exert his fullest capacity ; in the second we put him in a situation where spasm or weakness will exhibit in defiance of his efforts. This has been called a "muscle" test and what we call the + im- pulse is what the "muscle" testers call exophoria, meaning a tendency to turn outward from weakness of the internal recti ; which is a mistake, for it is really a tendency inward from too much inervation of the internal recti ; if we were naming it as they do it would have to be esophoria. Our impulse is an outward tending from weakness of the innervation to the interni and we would call it exophoria; the others call it esophoria, from weakness of the externi. Then they prescribe prisms and even operate, invariably making trouble unless the correcting lenses do more good than their prisms or opera- tions do harm. This matter will be taken up later. The temperamental influences on the nervous system are remarkable, particularly on people of mature years. There are four general classes : Good, Fair, Medium, Bad, with three subdivisions of each, as shown in Table 4. It is also a notable fact that the temperamental condition is almost invariably on an equality with the physiological one, the exceptions being due largely to dispositions developed by environment. The dynamic registration with correcting glasses on is the patient's Low line; adding to this according to the other tables gives the High line; the Safety and Danger lines are found by making equal divisions of the differ- ence between the High and Low lines. Then Class 1 is above the High ; Class 2 is High; Class 3 is below High but not half way to Safety; Class 4 is more than half way to Safety; Class 5 is at Safety; Class 6 below Safety 1GO A SYSTEM OF MATURE MEDICINE TABLE 4. Physiological Classification Fee Disposition and Temperament Class Add to Age for Temperament Add to fee for Disposition 1. High + 125% Good A -4- 12. . .0. ..0 2. High 100% Amiable Thoughtful A 10. . .0. ..0 25% 3. High 150% Considerate A 8. . 9. . .0 4. Safety + 1 175% Fair B+ 8. . .9. . .0 5. Safety 200% Honest Critical B 8. . .1. 15 50% 6. Safety 300% Reasonable B . 7. . .6.. .0 7. Danger + 8. Danger 9. Danger 450% 600% 900% Medium Careless Heedless Dishonest Silly c+ c c 7...6...0 6. .10. .15 6...3...0 75% in T nw 1 Bad T^ 1 6. . .3.. .0 nT.nw 94003^1 Stubborn Fanatical L> + 5. ..7.. 15 100% 12. Low- 500O% Deceitful Vicious D 5. ..0...0 but not half way to Danger ; Class 7 is more than half way to danger ; Class 8 is Danger; Class 9 is below Danger but not half way to Low; Class 10 is more than half way to Low; Class 11 is Low; Class 12 is below Low. When a patient is older than his High line it indicates a dangerous spasm condi- tion, and he is really as much below his high line as he appears to be above it. If one is at Low , or Class 12, and is still able to get around, there is something wrong with his registration. Ophthalmologists do not take cases who are physiologically below Class 6. They are for Neurologists. To utilize these tables there must be a regular procedure, indicated by the following blank forms, which are filled and the records proved before we can begin the analysis of a case : Symptoms. Appearance : History : Ophthalmoscope : Vision : Dynamics : Statics : Correction Vision : , Dynamics : Statics : Pupillary Distance : , Nose High : Base Wide : Crest : . Size of Lens : Between Lenses : . . . . Temple Distance : Style of Guard : . . . Discounts for Symptoms Points in Ten: Good, 1 to 2. Fair, 3 to 4. Medium, 5 to 6. Bad, 7 to 10. , Symptom Classification: Pts. App His Oph. Dyn Stat Total Points Per cent, of 50 . NEUROMETRIC METHOD OF ANALYSIS 161 Finally, the case is analyzed by using the next form, getting the data from the forms above. Discount temperament half as much per cent as for hyperopia and extra work, because the strain is not so direct nor so constant. Years Months Days Years Months Days Dynamics : D Hyperopia : D less % Extra Work : Hrs less % Temperament : less % High Line Safety Line Condition ...... Danger Line ' Low Line Date of Examination Remarks : Patient Born : Age : If the condition, with reference to the High, Safety, Danger and Low lines does not put the patient in the same class the actual age does, and within a few weeks of the same date, there is something wrong with the calculation or the work. See Table 4, physiological classification. If the patient is actually younger than indicated by the Condition we may have erred in adding too much for temperament, or we may not have discounted enough for symptoms. As these are the only two points where judgment is used the only other possibilities are clerical mistakes or carelessness in making the dynamic tests. Temporary lenses, approximating the correction are given together with such instructions as the analysis dictates, and a later examina- tion is made under better conditions, because the patient will not only im- prove physically in the meantime, but, having learned that the process is not a dangerous one, the mentality will be more composed for the second examination. An important feature of the Neurometer, exhibited in Table 1, is that theoretically, no glasses will be needed for close work only until about the thirty-fifth year, because the reserve, after accommodating for the 13-inch point, is as much as is being used. Practically, when the additions to Table 1 for temperament and hyperopia, when the latter exists, are considered, we find that no person under 45 years will ever need glasses for close work only. Those who ignore errors of refraction and prescribe glasses for near work cannot fail to cause trouble for themselves and their patients, because they do not touch the nerve strain produced by the effort to overcome the errors ; they only save a very small portion of the extra demand for the near work. The following specimen cases will contribute to a detailed understanding of the Neurometer, and the more it is used the greater will be the apprecia- tion of it. In forming an opinion with reference to temperament, we must utilize the appearance and history together with a knowledge of physiog- nomical indications, which are discussed in another chapter: Case I: Male. Appearance: About 5 ft. 8 in.; well proportioned; 155 pounds; complexion, medium (neither blonde or brunette) ; smooth face, well developed ; brown hair and plenty of it, parted on the left side; intelligent above the average ; neat ; healthy. 162 A SYSTEM OF MATURE MEDICINE History: Never been sick; neither smoked nor drank; expert accountant, worked nine hours overtime daily; good, practical education; normal interest in sports, passing events, etc., but no fads ; liked good literature ; at school was particularly interested in mathematics, geography, his- tory and business. Ophthalmoscope : Vessels numerous and of good calibre ; contents of arteries, good quality and quantity ; veins the same ; fundus normal. Vision : Normal with either eye. Dynamics: Near point 5 inches, 8.00 diopters. Statics: Red and white lights in line, O. K. Correction : None. The case proved to be emmetropic. Vision, Dynamics and Statics, same as at first test. Symptom Classification: Appearance, History, Ophthalmoscope, Dynamics, Statics, all Good, hence no need for discounts. Analysis:... Years Months Days Dynamics, 8.00 D 26 8 Extra work and temperament 12 High line 38 8 Remarks: An unusual case, hence 20 per cent, was added to the max- imum for temperament in lieu of adding for extra work, because that amount of work, while developing apparent excess accommodation, is not conducive to long life even in a normal person. The examination and analysis were made in August; the subject said he would be 39 in December. Case II: Female. Appearance: Medium height, about 5 ft. 6 in.; weight about 110; eyes blue ; hair light brown and thin ; complexion below normal, indicating malnutrition ; classification, 2, between 20 and 35 ; bust development small ; nose pointed ; lips thin ; medium chin ; ears without lobes ; hair dressed in prevailing fashion ; clothes neat and clean ; hands slender ; finger nails clean and polished; no jewelry; average intelligence; neither pretty nor ugly ; carriage erect and evidently in fair to good condition, comparatively, that is for one who applied for treatment. History : Stenographer and bookkeeper, working eight hours daily ; noth- ing congenital ; no infection ; malnutrition -indicated by indigestion, headaches, constipation, scant menstruation, deficient appetite ; no physical shock ; no mental shock ; physiological strain from evident re- fractive error and probable overtaxation at work ; no mental strain, except some worry because she had not found relief elsewhere ; no bad habits save wrong eating; occupation rather trying at times; atmo- spheric conditions such as are common in city offices, with improved conditions at home ; lived with parents in suburbs. Ophthalmoscope : Arteries pale ; veins a trifle dark ; vessels small but average number; fundus pale. Vision : Normal with either eye. Dynamics : Near point 4 inches, 9.00 diopters. NEUROMETRIC METHOD OF ANALYSIS 163 Statics : A impulse of 4 degrees. Correction: L.+1.50; R.+1.50. Vision : Normal. Dynamics: Near Point, 3^ inches, 11.00 diopters. Statics : A impulse of 1 degree. Pupillary Distance : 57 mm. Nose : High, 3mm. ; Base, wide, 16 mm. ; Crest, back 3 mm. Size of lens : eye ; between Lenses, 18 mm. Temple distance : Medium, 6^ inches. Symptom Classification: Discount. Appearance, Fair 3 History, Fair 3 Ophthalmoscope, Fair 3 Dynamics, Good 1 Statics, Medium 5 Total Points 12 Per Cent, in 50 24 Analysis: Years Months Days Years Months Days Dynamics, 11.00 D 17 6 17 6 Hyperopia, 1.50 + extra work 4 hours, equals .75 less 24% 3 5 24 Hy., or a total Hy. 2.25 470 less 12% 6 7 6 Temperament, B 7 6 Condition 27 7 High Line 29 7 Year Month Day Safety Line 25 6 2O Date of Examination 1914 8 22 Danger Line 21 6 10 Patient Born 1887 2 2 Safety Line 17 6 Age 27 6 20 Remarks : Physiological class 3. This patient came with -|-1.50 pre- scribed for near work only, by an oculist. We ordered them worn constantly, stopped work for two weeks, changed diet habits. At the end of a month all symptoms had disappeared, she looked well, felt well, registered 12.00 dynamically and O. K. statically, all headaches, constipation and other dis- orders gone. Taking the dynamic showing, which indicates 15 years and add 12 years 1 month we have 27 years 1 month as her high line and she is a trifle above it. With a word of caution we let her go. CASE III : Male. Appearance : Height, 5 ft. 7 in. ; weight, 140 ; complexion, dark and sallow ; evidently "grouchy"; something lacking in youthful opportunities or training; has in him the making of a good citizen. History: Headaches for twelve years; dyspepsia; dates his trouble from beginning to wear glasses, but can't get along without the ones used; was dull in school and finally quit a sixth grade because he couldn't get along with teachers ; burned his books and defied his parents. Exhibited antipathy to doctors while being questioned; insisted he knew more than any.. I stopped right here and settled that matter by telling him to go to the devil and treat himself; or, behave him- self and give me a guaranty of decent treatment by paying my fee at once in advance. He cooled down, became tractable and remained in that condition. Occupation, grocery clerk. 164 A SYSTEM OF MATURE MEDICINE Ophthalmoscope: Vessels abundant; arteries and veins in good condition, except veins a little too dark ; fundus O. K. Vision : Very bad, 20/200 each eye. Dynamics : No good ; couldn't register. Statics : Normal. Correction: Required +7.00 each eye. Been wearing -f-5.50. Vision : Normal. Dynamics : Near point, 4 inches, 9.00 diopters. Statics : Normal. Pupillary Distance : 60 mm. Nose : High, 3 mm. ; Base wide, 18 mm. ; Crest, back 3 mm. Size of lens, 00 eye; between lenses, 20 mm. Temple distance, 7 inch. Symptom Classification: Discount Appearance, Good 1 History, Good ^ 1 Ophthalmoscope, Good 1 Dynamics, Good 1 Statics, Good 1 Total Points 5 Per Cent, of 50 10 Analysis: Years Months Days Years Months Days Dynamics, 9.00 D 23 4 23 4 Uncorrected Hy. 1.50 .... 7 6 less 10% 6 11 Temperament, B 7 6 less 5% 7 1 15 High Line 38 4 Condition 37 4 15 Safety Line 33 4 Year Month Day Danger Line 28 4 Date of Examination 1913 5 29 Low Line . 23 4 Patient Born 1876 3 19 Age 37 2 10 Remarks : Physiological class 3 ; this patient is an illustration of how mental conditions contribute to the disturbance, reflexly, after the physio- logical strain has set up the original irritation. His story was not as bad as it sounded. We got his final correction at one sitting and he was soon a different person. Case IV: Female. Appearance: Height, 5 ft. 6 in.; weight, 115; brunette; moody; sallow. History: Never been well nor happy; found fault with her husband and everyone else, unless she could have her way ; was under my observa- tion for three weeks before examination; indigestion and bad dispo- sition. Had grief periods and wailings. Ophthalmoscope : Vessels normal size and calibre ; number normal ; arteries pale; veins O. JC. Vision: Normal. Dynamics : Near point 5 in., 7.00 diopters. Statics : A impulse of 3 degrees. Correction : Required +2.00 each eye. Been wearing -(-1.25. Vision : Normal. NEUROMETRIC METHOD OF ANALYSIS 165 Dynamics: Near point 4 in., 9.00 diopters. Statics : A impulse of 3 degrees. Symptom Classification: Discount. Appearance, Good 1 History, Fair 3 Ophthalmoscope, Good 1 Dynamics, Good 1 Statics, Bad 7 Total Points 13 Per Cent of 50 '. 26 Analysis: Years Months Days Years Months Days Dynamics, 9.00 D 23 4 23 4 Uncorrected Hy. .75 8 9 less 25% 6 6 21 Temperament D 5 less 12i% 4 4 15* High Line 37 1 Condition 34 3 6 Safety Line 32 6 Year Month Day Danger Line 27 11 Date of Examination 1909 2 7 Low Line 23 4 Patient Born . . . 1874 11 2 Age 34 3 5 Remarks: Physiological class 4; the discount figures show 26 per cent., but for convenience I sometimes call such a case 25 as it figures easier. In this instance it figured within one day of her age. Had I figured the 26 and 13 it would have given 34 1 27, putting her in the same class. Case V: Female. Appearance : Delicate ; 5 ft. 4 in. ; weight about 100 ; blonde ; actions in- dicate a nervous temperament; intelligent. History; Dysmennorrhoea, with; flooding every three weeks; headaches; indigestion and bloating; pains in the back; been treated medically but never operated, although, advised that was the only help; un- married because she realized she was not fitted physically for that re- lation ; school and college education, but did not graduate from college on account of ill health. Eyes inflamed, with granulation; been in the care of oculists who used silver nitrate, atropine and other drugs, without relief. Appetite irregular and morbid; prefers sweets and starchy foods; lives with parents and assists her mother in household cares ; they keep servants. Ophthalmoscope : Vessels few in number but of fairly good size ; arteries pale ; veins medium ; fundus pale ; blood quantity below normal. Vision : L. 20/30 ; R. 20/40. Dynamics : Near point 4 in., 10.00 diopters. Statics : A-f- impulse of 4 degrees. Correction: Accepted +1.50 .75 axis 180; R.+1.50 1.00 axis 180. Vision : Normal. Dynamics : Near point 3| in., 11.00 diopters. Statics : A+ impulse of 3 degrees. 166 A SYSTEM OF MATURE MEDICINE Symptom Classification: Discount. Appearance, Fair 3 History, Medium 5 Ophthalmoscope, Fair 3 Dynamics, Good 1 Statics, Good 1 Total Points 13 Per Cent, in 50 26 Analysis: Years Months Days Years Months Days Hyperopia 2.00 D . . . 5 6 less 26% 3 8 12 669 Temperament B . . . 7 less 13% High Line .. . 27 6 4 2 Condition 25 2 21 Year Month Day IQIO C Q Safety Line . . . 23 Danger Line . .. 19 Low Line . .. 15 1 8RS 2 7 Age 25 4 2 Remarks : Physiological class 4. The dynamic test after correction showed only 1.00 diopter increase, when it should have been at least 1.50; the static test showed a -(- impulse before and after correction, proving we did not get all of the hyperopia; therefore, adding -4-50 for the 3 degrees spasm, -{-2.00 spheres were prescribed, regardless of vision, for temporary wear, and that amount was added to her first dynamic showing to get the evident dynamic exhibit, because the hyperopia had to be overcome before starting on the 10.00 diopter showing at the first test ; ordered rest ; change of diet ; hot baths and plenty of sleep ; physical exercise at monthly periods ; cold salt water as a collyrium ; return for report at weekly intervals. At the end of three months menses were regular and floodless ; headaches and other symptoms all gone, even to the eye granules ; had gained six pounds ; reg- istered 13.00 with final correction on; L.+1.25+.75 axis 90; R.-f 1.00+1.00 axis 90 ; static test O. K. Case VI : Male. Appearance : Tall ; slender ; delicate ; face and hands ashen ; black hair and eyes ; intelligent ; would be fine specimen if well. History: Indigestion, etc., from sedentary habits; occupation, teacher of phrenology ; gave many free lectures when he should have been on sick leave ; not been well for several years, but never consulted physicians; only came to me because one of my pupils and his friend insisted on an examination. Very little to his story to suggest the condition found. Bad eater. ( )phthalmoscope : Vessels large and numerous, but arteries nearly empty and blood away below normal ; veins dark and sluggish ; fundus, dull. Vision: Normal. Dynamics: Near point 10 in., 4.00 diopters. Statics : A impulse of 10 degrees. Correction: L.-J-1.25; R.-f-l.oO; R. the fixing eye. NEUROMETRIC METHOD OF ANALYSIS 167 Vision : Normal. Dynamics : Near point 6 in., 6.50 diopters. Statics : A impulse of 10 degrees. Symptom Classification: Discount: Appearance, Bad 7 History, Bad 7 Ophthalmoscope, Bad 10 Dynamics, Fair 3 Statics, Bad 10 Total Points 37 Per Cent, of 50 74 Analysis: Years Months Days Years Months Days Dynamics, 6.50 D 32 32 Hyperopia 1.50 D 7 6 less 74% 1 11 12 Temperament A -f- 12 less 37% 7 6 21 High Line 51 6 Condition 41 6 3 Safety Line 45 Year Month Day Danger Line 38 6 Date of Examination 1903 5 20 Low Line 32 Patient Born . . . 1862 6 3 { Age 40 11 17 Remarks: Physiological class 7. Close to his danger line by actual measurement, taking the best possible view of the case. He was told he must stop all work at once and begin a series of most careful treatments, as his body chemistry was bad and if he neglected it longer it would grow worse rapidly; that if he neglected the warning he would die inside if sixty days and would, exhibit what the health office would call a bad case of smallpox, but he would be conscious to the last minute, because the trunk lines to his brain were able to carry nourishment there but the lack of quantity had re- duced the pressure until the capillaries of the body generally were not used, hence the skin exhibit. He smiled benignly and told his friend later that I was a bright man, but too enthusiastic over my Neurometer. The friend cautioned him, because he was an old-school doctor of many years practice and had taken the course with us. He did not follow instructions and died on the forty-fifth day. The health office pronounced it smallpox of the most virulent type and quarantined his office and residence for two days, when they heard of my prognosis and withdrew the quarantine, changing their "diagnosis" to "neurasthenia." His widow told me he was conscious to the last minute and talked to her up to an hour before he died. Case VII: Male. Appearance : Short ; fat ; happy-go-lucky ; nervous temperament ; good color and would be called well by all except those of us who know that no person under 6 feet tall and over 200 pounds weight can be healthy, Neurologically. History: Good, except his manner of living; hearty eater and considered himself an epicurean ; a Homeopathic surgeon with a big practice and overworked. Ophthalmoscope : Good showing, except blood plethoric. 168 A SYSTEM OF MATURE MEDICINE Vision : Normal. Dynamics : Near point, 6 in., 6.50 diopters. Statics: A-J- impulse of 3 degrees. Correction : L. and R.-J-.75. Vision : Normal. Dynamics: Near point, 5| in., 7.00 diopters. Statics : A-f- impulse of 5 degrees. Symptom Classification: Discount. Appearance, Good 1 History, Bad 7 Ophthalmoscope, Fair 3 Dynamics, Fair 3 Statics, Good 1 Total Points 15 Per Cent, of 50 30 Analysis: Years Months Days Years Months Days Dynamics, 8.00 D 26 8 26 8 Hyperopia 1.50 D 7 6 less 30% 5 3 Temperament A +...... 12 less 15% 10 2 12 High Line 46 2 Condition 42 1 12 Safety Line 39 8 Year Month Day Danger Line 33 2 Date of Examination 1903 3 16 Low Line . . 26 8 Patient Born . . . 1860 6 6 Age 42 9 10 Remarks : Physiological class 4. The bad features of this case were that his nervous tension was so great that he could not register properly dynamically; adding .75 to the -J-.75 correction accepted, because of the + impulse, making a total correction of 1.50 needed, and adding that to his first showing we got the dynamic 8.00 ; then his attitude toward our methods and toward himself told us he would not follow instructions if we gave them ; his blood pressure was great and the sort ofi food he was eating tended to reduce the resistance of the vascular walls. There was nothing to do except to tell him we understood his skepticism and took no offense because he evidently intended none ; but, we did tell him that he would die of "apoplexy" within three years. He laughed, slapped me on the back and told me he would outlive Methuselah's record. Two and a half years later I received a paper from his home town announcing his death from "apoplexy" and comment was made on the fact that a Chicago doctor had told him he he would go that way within three years. Now let no one get the idea that because I have foretold the deaths and manner thereof in some cases in advance that it is claimed possible to do it all the time. That would be foolish. I have had thousands of cases and have only had comparatively few such. Happily I have had a considerable number who were in bad condition but followed instructions and recovered. It is a coincidence wor- thy of note that in not a single instance among those who died did I get a fee nor would I if they had followed instructions, as they were all friends of myself or my students who were brought to the college as clinics. I have found that those who are concerned enough to pay a fee will do as they are told. The moral is : Always get a fee. NEUROMETRIC METHOD OF ANALYSIS 169 These specimen cases are sufficient to show that no two cases are alike ; that the practice of true ophthalmology is not to be compared with the work of oculists and "optometrists," and that retinoscopy is a joke. Important features of the Neurometer are: First, the dynamic test after approximate correction of the errors, in- dicates a certain age by Table 1; to this add for the hyperopia and extra work, if there be any, Tables 3A and 3B, and the total will indicate the patient's physiological high line. If his actual age is below that the case will be found near the danger line in the final analysis. Second, taking the total, as found by the addition for dynamics and hyperopia, as above, and if the real age is above it the difference indicates the temperament, by Table 4, less the discounts for symptoms, physiological and temperamental. For example: With a -\- 2.00 correction a patient registers 10.00 diopters which indicates by Table 1, 20 years, months, days ; to this is added 5 years for hyperopia, Table 3A, making 25 years. Pa- tient says he is 32, a difference of 7 years, hence this is his temperament, Table 4, except that we have found the symptoms indicate a discount of 30 per cent, physiologically and 15 per cent, temperamentally, therefore 7 years, plus the 30 per cent, discount from the 5 years added for hyperopia, is only 85 per cent, of his real temperament; Thus, 7 years plus 1 year 6 months is 8 years 6 months, or 102 months ; this, divided by 85 and multi- plied by 100 gives 120 months, or 10 years, Class A as his normal tempera- ment. Third, when the condition found by analysis and the patient's actual age differ more than a few weeks, if the age is below the indicated condi- tion we prescribe by that ; if the condition indicated is lowest we prescribe accordingly, thus we are always on the safe side for both patient and our- selves. Fourth, If a patient is found near his high line we may allow considerable liberty, unless he is above the high line, when rest is imperative. If near his safety line advise rest for a week. If at his safety line or below it order rest and refuse the case unless orders are obeyed strictly. If near the danger line an ophthalmologist may prescribe glasses and rest but should also send the case to a Neurologist. Fifth, there are instances, such as the last two of the specimen cases, where there are special reasons for regarding the situation as dangerous, even when the patient makes a pretty good showing by the tests. It is only by training in physics, anatomy, physiology, symptomatology, analysis, dietetics, metaphysics and prognosis that the practitioner is able to attain skill and diplomacy in handling such cases. Sixth, It is our policy to exercise care with even the most ordinary cases, in order to form the habit ; then, while we do not believe in doing or saying anything that will frighten a patient unnecessarily, we can not avoid telling the truth as we find it by analysis, and, as a rule, our patients appreciate the fact that we are measuring, not guessing. Seventh, The fee column, Table 4 starts with 100% at the high line. In Neurological cases $100 is the indicated fee. In ophthalmological prac- tice it is less, of course, and it is left to the practitioner to substitute his 170 A SYSTEM OF MATURE MEDICINE minimum fee in this place and the others will adjust themselves according to the per cents, specified. Eighth, the addition to fees for disposition is an important matter. Even Class A may be influenced by outsiders, jealous doctors, or just fool laymen, hence this is a reminder to look out for that and protect yourself and Nature by getting all fees in advance as a guaranty instructions will be followed. You know the laws will work, if given opportunities, and you place the responsibility where it belongs with the patient. The very best feature of the Neurometer is that it works best when it doesn't work. By which statement I mean that if a patient is in such a state of nervous disorder that our analysis develops High, Safety, Danger, Low lines and a Condition indication at variance with his or her actual age we are able to utilize the data to find the reason for the showing, the details of which can only be demonstrated clinically ; but the reader need not fail to profit by this paragraph because such a showing in any case tells at once that the patient needs immediate care, temporary correction, rest, etc. If a patient is actually older than the years, months and days given as his High line, take the difference and subtract it from his high line, when it will, as a rule, correspond to his condition showing. It means that his system is in a state of temporary irritation and we put him in class 1, physiologically, which is an abnormal state, 2 being the High line or normal physiological condition. CHAPTER XIX. ^ Cyclophoria Often the Cause of Apparent Oblique Astigmatism. Cyclophoria is a rotation of the eye-balls on their longitudinal axes. It is of two varieties, corresponding to the -f- and - - impulses described else- where. The first is produced by nervous spasm exhibited through the in- ferior oblique muscles. The second is nervous exhaustion exhibited through the same muscles. It is discoverable only when there is astigmatism ; many cases of apparent oblique astigmatism are due entirely to it, and the great discomfort produced by lenses prescribed under such conditions puzzled oculists and opticians, many of whom have been forced to regard such as "difficult" cases. The inferior obliques are supplied by branches of the third nerves, hence, when the efforts to overcome hyperopia have so reduced the supply that the general nervous system has become irritated, exhibiting spasm of accommodation and -f- impulses by the static test, it is only natural to expect the inferior obliques to be involved ; sometimes spasm only exhibits in these muscles, because the other branches are under control, and it is, therefore, an important item for consideration aside from the fact that it presents false axes for the astigmatism. Fig. 105 shows in solid lines the normal positions of the vertical and hor- izontal meridians of the two eyes as they would be seen with patient facing the operator. With a spasm of the nervous system, exhibiting through the inferior obliques, these two* principal meridians will be shifted to the dashed lines, and the test may show the deviation to be anywhere from a few degrees to as much as thirty. Whenever such a case is found the proper thing to do is to prescribe temporary spheres and order rest for a week, when it will be found in a vast majority of instances that upon reexamination the two meridians will be vertical and horizontal and the patient will invariably A SYSTEM OF MATURE MEDICINE accept more -|- sphere in the correction than at the first test, thus proving doubly the existence of spasm. Fig. 106 shows the reverse condition, from nervous weakness ; the supply being deficient, the inferior obliques have less tension and the natural pull from the elasticity of the superior obliques roll the eye-balls inward above so that the principal meridians appear as the dashed lines, the amount of deviation being regulated by the amount of the deficiency of course. As has been shown in the chapter on tri-curved surfaces, all regular, nonspherical, curved surfaces have their two principal meridians always at right angles ; hence such a thing as regular astigmatism with the two prin- cipal meridians not at right angles is an impossibility. It is also a fact that in all toric surfaces, such as are presented by all astigmatic eyes, the secondary principal meridians are exactly half way between the primary principal meridians. Thus, the primary principal meridians being at vertical and horizontal positions, the secondary meridians will be at 45 and 135 respectively. The anatomical arrangement of the rectus muscles is such that when there is true oblique astigmatism it would be most likely to have its primary principal meridians on the positions of the secondary meridians of the regularly astigmatic eyes, because of the vertical and horizontal pull of the tension of the recti muscles. Fig. 107 shows the second probable position of the principal meridians and the positions they would be shifted toward in cases of spasm. I had one case, a student, who had been wearing an over-correction of compound myopia with the axes of his cylinders at L. 150; R. 30. He had worn the lenses a long time and exhibited many symptoms of hyperopia, such as irritability of temper, headaches, indigestion, etc. He had been in optical work nearly all of his life and was skeptical when told that he was a hyperope with his glasses on and that he must be cyclophoric because of his complaint that object appeared distorted. He made a fine clinical specimen for the class because of his assurance and the manner in which he was handled. No attempt was made to give him good vision at first ; but he was given lenses CYCLOPHORIA AND OBLIQUE ASTIGMATISM 173 of sufficient power to enable him to go about safely. After a week or two we went over the case again and secured normal vision with very much weaker lenses than he had been wearing. As a matter of precaution I re- moved the astigmatic charts while making the refraction test, in order that we might give him the surprise I was sure was coming. His principal meridians were vertical and horizontal and when I attempted to shift the axes of the cylinders to the positions in which he had been wearing them he set up a mighty protest, declaring he could see nothing. It was very evident he thought the axes were in the same old place and that I was trying to force them to my chosen position. The other students enjoyed it all immensely. When I said "Well, if you must have the axes on those meridians we will have to let you have them" he let out his enthusiasm over my supposed de- feat. The class fairly howled: "Take off the glasses and look where the axes are." He was rather stunned to find he had been fighting for my position. But he joined the laugh on himself and made a good student. Fig. 108 shows the reverse condition, when the nerve supply is weak. All four illustrations are products of nervous conditions exhibited through third nerves and the inferior obliques. I do not mean to say there is never oblique astigmatism with the prin- cipal meridians at other positions than the four meridians given; but there is so much danger in prescribing oblique cylinders when the meridians are not at 45 and 135 that it is safe practice to proceed with care and temporary spherical lenses. There are instances of high amounts of astigmatism in which the axes are at other meridians ; but in the lower amounts, where it is not sufficient to impair vision greatly, cyclophoria will be developed as the cause of the unusual axes in nearly all cases. Lest some reader assumes I have forgotten something I will add that no treatment is needed other than the temporary spheres and rest until the nerve supply is reinforced. It is the same with all other so-called "muscle troubles," even to cross-eyes, as I shall show in another chapter. We do not need any tests for cyclophoria because we are after the Causes. One of the old-school oculists proposed a test as follows : "The eye under examination should be covered and the Maddox double- prism placed before the other eye. A card on which a horizontal line is drawn is held 18 inches from the eyes, and the patient fixes upon the line, when two lines are perceived by the action of the prism ; then the cover is removed from the other eye and three lines are seen, the third or new line being between and parallel to the other lines if orthophoria is present. If there is any imbalance of the oblique muscles, the third line will be tilted 174 up or down obliquely." He says if the nasal end tilts down it means weak- ness of the superior oblique muscle, and if it tilts up it indicates weakness of the inferior oblique muscle. There are two weak spots in his proposition : The first is, of course, the fact that the muscle is not at fault, because its actions all depend on the nerve supply. The second is that if the vertical meridian of the eye was the one of greatest power, what he says would happen would be true ; but if, as is sometimes the case, the horizontal meridian had the maximum curve, the reverse would happen. Again, the two lines seen by the eye wearing the double-prism would not be at all likely to appear horizontal, unless there was no astigmatism, because like all other "muscle troubles," it is nerve trouble and both eyes would exhibit it. They have "clinoscopes," "cyclophorometers," "cyclo-duction" and other "tests," with mystery galore. They operate and prescribe prisms ! The latter proposition suggests cork-screws to me so forcibly, I cannot refrain from recommending them instead of the prisms. They would certainly be as consistent with common sense. They remind me of one Gould, compiler of dictionaries, who in col- laboration with "L. Webster" Fox, once perpetrated the following "bull" in a quiz compend : "Astigmatism is an invisible and elusive imp of mischief, requiring much patience and keenness to hunt him down. His hiding place is the ciliary muscle; his disguise, amblyopia. He hates atropia as his father was said to hate holy water." Now, anyone who knows anything about physical optics and eyes gen- erally, knows that astigmatism is not an "invisible, elusive imp" ; that it requires no "patience to hunt him down" ; although it does require some skill, but not nearly so much as is required to get all of the hyperopia. Any competent Ophthalmologist knows that instead of a "disguise," amblyopia is the thing that exposes the astigmatism, and he knows that astigmatism is not affected one whit by atropine. The whole story is crooked, clear down to the "holy water." Don't let anyone deceive you about cyclophoria, reader. Whenever you find oblique astigmatism, practice the temporary lens and building-up-the- nervous-system method ; you will win all the time. CHAPTER XX. Physiological Action of Prisms, with Proofs of Their Unvalue. L 1 1 1 . I r t fc 1 1 * 1 % 1 1 1 Take a piece of white paper four feet long and with an ordinary black crayon draw a diagram after Fig. 109, making the vertical lines four inches apart; have a small candle or electric light in front of the line L. Then seat a person fifteen or twenty feet from the light; put on the trial frame; adjust it so the patient looks through the centers of the cells; cover the right eye with the black disc; put the plane red glass in the cell behind it; put the double-prism on the left eye and adjust it so two white lights are seen, one directly above the other ; uncover the right eye and the red light should be seen in line with the two white ones and half way between them. As a general rule this indicates normal balance of the nervous distribution and is known, with reference to the eyes, as orthophoria, meaning correct tending. Any deviation will exhibit a displacement of the red light and it is termed heterophoria ; but it is subdivided, according to the. location of the red light, into esophoria, inward tending; exophoria, outward tending; hyperphoria, upward tending; cataphoria, downward tending; hyper- esophoria, upward and inward tending; hyper-exophoria, upward and out- ward tending; cata-esophoria, downward and inward tending; cata-ex- ophoria, downward and outward tending. We do not use the terms above described, in order to avoid confusion. If the red light is seen to the left it is a + impulse ; if to the right it is a impulse ; if above or below the center, but in line, it is or , the dot locating the position of the red light above or below the center ; if above the center and to the right or left it is indicated - or _^; if below and to right or left it is r or^ ; the latter deviations mean an erratic distribution of the nerve supply. We never prescribe prisms for such symptoms any more than we would prescribe hypodermic injections of morphine for pain or internal medicines for corns. We will show plenty of good reasons why Nature is leading us aright while the self-styled "authorities" are persisting in wrong-doing be- 176 A SYSTEM OF MATURE MEDICINE cause they are ignorant of Physics, of Anatomy, of Physiology and hence, necessarily, of Therapy. To ascertain the physiological value of prisms, take as a subject one who is practically emmetropic and orthophoric, and, when he has fixed on the diagram, seeing two with the double prism on left eye, place a 4-degree prism, base out, before the right eye, then uncover it by removing the black disc; have him locate the position of the red light with reference to the numbers on the left end of the chart; now remove the trial frame and have him hold two strings, one under the center of the pupil of each eye ; have an assistant take the other ends and hold them, the one from the left eye on the line L where it crosses the horizontal line and the other on the hori- zontal line at the point designated by the patient as the point where the red light appeared; these strings represent the two axes of the eyes and the point where they cross each other will be found approximately 1 meter from his face. This is the angle of convergence caused by the prisms, and re- quires a convergent movement of .50 diopters by each eye. Theoretically this brings with it, automatically, 1.00 diopter of accommodation in each. Practically, the capacity for adaptability prevents this from exhibiting in all instances, but emmetropes have always exhibited a decided dimness of vision on the letter chart when a 2-degree prism was placed before each eye, thus proving the theoretical proposition ; and even others who see pretty well with the prisms on, over their corrections, soon complain of the strain, adding corroboration to the emmetropic showing. Therefore, taking the 4- degree exhibit as a basis, we have: For convergence : . . . / L. .50 Automatic > T ' .,'QQ Accommodation < D ' ./_ ^ K. 1.00 Total 3!00 Figuring by the second, as in other calculations, we have : 3X60X60X16 = 172,800 units demand per day of 16 hours, or 43,200 units per degree, up to the limit of capacity of the patient to adapt himseH to them and see singly with the two eyes. The average capacity for prisms in this position is about 20-degrees, or 864,000 units daily, or the equivalent of 3.75 diopters of hyperopia. It is not remarkable then that the prism fiends found that patients would not "tolerate" strong prisms, nor that Maddox says in his book on prisms, page 28, that 4-degrees is the maximum prism to be used, no matter what the degree of "muscular error." If the prisms are placed bases in, the demand is altogether on the sixth nerves, which have no other nerves associated with them, so only the .50 divergent pull by each eye is needed, hence, theoretically, the demand is only one-third as much as when the prisms are base out; but, inasmuch as we did not charge anything for the evident strain through other branches of the third nerves, with prisms in the first position, we have placed the demand for bases in at one-fifth as much as for bases out ; this gives strain as 8,640 per degree, and the limit of capacity is about 8-degrees. For prisms base up or down the demand is on the third nerves again, and while it has not been possible to measure the strain exactly we have PHYSIOLOGICAL ACTION OF PRISMS 177 estimated it at one-third as much as if base out, or 14,400 units per degree, with a capacity limited to about 4-degrees. Now take any person who exhibits deviation by the test, but who holds his eyes in line when the test is removed, so that he sees singly, the effect of prisms would certainly be identically the same as for the emmetropic and orthophoric person. Even an "oculist" or "optometrist" ought to see that clearly. I have been practicing on this proposition nearly twenty-five years with uniform success and I have yet to prescribe my first prism for " 'phoria." It is only one of the many symptoms patients exhibit to prove the strain is from the effort to overcome the error of refraction. I have had hundreds of cases where prisms had been prescribed, some with very bad effects, others with slightly bad effects, others with no apparent effects and others with "good" effects. I was interested to learn the reason for this variety, admitted by the prescribers and attested by the victims. Investigation yielded fine results. One case of "good" results is worth giving in detail: Away back in 1895 one of my former pupils came into the school-room one day and proudly announced that he had seen my prism story knocked into a cocked hat by a correspondence graduate ffom Dr. Allen's "school." His cousin, a young lady, who had 16 degrees of "esophoria" had been "cured" of 12 degrees of it in one month by a pair of 2-degree prisms base out. That was a stunner ; but as it came from a man who had been a farmer and graduated as a horse doctor after drenching a horse once, became a druggist and jeweler by purchasing a store, and a photographer because he sold kodaks, I had the impertinence to ask him for a bill of particulars. He produced the prescription. Here it is : R.-J-2.50, 2-degree prism base out. O, 2-degree prism base out. Then I went for him. He had been taught in my school how to figure the strain from hyperopia, and was giving credit to the prism for the good ef- fects when it was very evidently due to the -4- 2.50 spherical len'ses ; but like a great many others who have been taught the truth and had it proved to them, he preferred to accept the bluffer's story until after I had finished with the "following explanation. The strain on the patient, uncorrected, was : t- A L. 2.50 ror Accommodation : .............. -p 59 Automatic Convergence : ........... :~ IV. I ..-' Negative pull 6th nerves : ....... L- 1-25 R. 1.25 Total ....................... ? 10.00X60X60X16 = 576,000 units, all of which was saved by the lenses, making patient an emmetrope, pro- vided 2.50 was the total amount of hyperopia. Then putting the prisms on caused a strain of 172,800 units daily, which, deducted from the 576,000 saved by the lenses, left a net saving by the lenses of 403,200, in spite of the prisms. That was why the prisms did "good" in that case. He saw the point and came over to my side at once. Then I knocked him down with the follow- ing proof that the prisms really did good in that case : 178 A SYSTEM OF MATURE MEDICINE I proposed that we consider the patient a hyperope of 3.50, because I knew no Allen graduate ever came within a diopter of a correction; there- fore the strain would be: For Accommodation : L. 3.50 R. 3.50 Automatic Convergence : L. 1.75 R. 1.75 Negative pull 6th Nerves : L. 1.75 R. 1.75 Total 14.00X60X60X16 = 806.400 units. Of this amount 576,000 was saved by the + 2.50 spheres prescribed, leaving a hyperopia of 1.00 diopter uncorrected, necessitating the strain : For Accommodation : L. 1.00 R. 1.00 Automatic Convergence : L. .50 R. .50 Negative Pull 6th Nerves : L . -p R. 50 Total 4.50 ; but, the 2-degree prisms bases out, made the .50 convergence in each eye a necessity, while the accommodation took care of the hyperopia so no negative pull was needed ; thus the prisms actually saved one-fourth of the day's strain from the uncorrected error, or 57,600 units; a total saving by lenses and prisms of 633,600 out of the total strain of 806,400, leaving a balance of 172,800 strain which could be saved by leaving the prisms out and adding -)- 1.00 to the lenses. He went home and made a test by our methods, found the hyperopia 3.50, prescribed it and in a week all the "muscle trouble" was gone. Incidentally it may be remarked that for any amount of hyperopia trie prism which will necessitate the convergent pull which is due automatically with all efforts of accommodation, will save one-fourth of the strain caused by the error. Anything else will cause trouble, either by adding to the strain or not saving as much as could be done with the right prism. But who is fool enough to relieve one-fourth of the strain with prisms when he can relieve it all with the correction in full? If 2-degrees on each eye will save one-fourth of the strain on a hyperope of 1.00 all that is necessary to find the prism for any amount of hyperopia is to multiply 2 by the number of diopters of hyperopia in the fixing eye and put that much prism on each eye. Even if there is a diplopia it does not mean prism or operation. It means that the patient is in such a state of spasm or weakness that' abso- lute rest is needed. And, let me remark here, either exhibit is proof of insufficient nerve supply; but the spasm indicates nearer a normal supply than weakness does. See the chapter on cross-eyes. Now we come to another side of the story. I am almost ashamed to tell it. If it had not been proved so positively and in so many ways I would keep quiet : The "accepted authorities" did not and do not know Physics, Anatomy, or Physiology. First, they declare that when the lights deviate in one direc- tion the eyes deviate in the opposite one. As a physical proposition this could not be true and both eyes see equally well. Physiologically, all that is necessary to prove it false is to take a case that sees the red light to the right and drop a prism, base out, in front of it, when it will turn in per- PHYSIOLOGICAL ACTION OF PRISMS 179 ceptibly, proving it must have been turning out before, and proving that if their claim was true the turning in of the eye would put the light farther to the right, which it does not do but does the contrary. They, evidently, never watched the eye, but assumed that because a prism breaks rays to- ward its base and the eye sees through the prism in that position it is proof the eye turned in; they forget that the eye saw before they put the prism on as well as after, hence must have adapted itself to the new arrangement. Therefore, what they call esophoria is really exophoria; what they call exophoria is esophoria ; what they call right hyperphoria is left hyperphoria, etc. In short, the eyes deviate in the same direction the lights do in all cases of 'phoria. Note that I say eyes; for they are wrong a second time when they declare one eye alone does the deviating. Never. Try this experi- ment: Have a subject take a 10 or 20-degree prism and hold it base out in front of his right eye, the other being closed, and you will see the eye turn toward the nose decidedly; now have him open both eyes and repeat the performance on the right eye, but you watch the left and you will see it turn first toward the left, with its fellow, but immediately it will con- verge with a jerk and he will tell you he sees singly; now, have him remove the prism suddenly when the right will turn out to its normal position while the other will first turn in, then let loose its convergence and turn out to its position. If you want any better proof that both eyes turn, come to me per- sonally and I will supply more it couldn't be better. Third, after "diag- nosing" and declaring prism treatment would do the work and finding it failed, of course, they resorted to operation and "graduated tenotomies" became a great fad, until the oculists became involved in damage suits; then they stopped with suddenness and one very prominent man in New York told a friend of mine that prisms and operations are no good be- cause he had tried them and found it out. Yet he talked and wrote against "empirics." Fourth, and worst of all, they did not and do not know that muscles are only the mediums through which nervous energy is applied, hence their talk about "muscle troubles." If they knew anything of anatomy and physiology they would not expose themselves ; this is the only reason I have not denounced them individually as criminals for their operations and prism "exercises." Ask any prescription house and you will be informed there is not one prism prescription comes in now in proportion to twenty- five a few years ago. That is the final proof of my contention. When I published my little primer, "Optical Truths" in 1898, their "eminences" declared I was a number one fool. But I had the truth and could prove it. I got my story from Nature, not from alleged "authorities." My ex- periences have taught me to advise my pupils that the greater the "author- ity" the more watching he needs., Another hobby of the "oculists" and their imitators, the "optometrists," is the "Duction Test" of the Muscles : Adduction is caused by placing prisms, bases out, before the eyes and finding the strongest a patient can overcome with his internal recti and see a light singly at fifteen or twenty feet. The "rule" is that if the interni can- not overcome at least 20 degrees prism they are too weak and their an- tagonists, the externi, must be cut; but if they overcome more than 24 de- 180 A SYSTEM OF MATURE MEDICINE grees they are too strong and must be cut. Imagine a muscle too strong, if you can. Abduction is produced by placing prisms, bases in, before the eyes and finding the strongest the externi can overcome and maintain single vision. The minimum is 6 and the maximum 8 degrees, and the penalties are : if the externi are too weak their antagonists, the interni, must be cut; but if they are too strong they have to be knifed. Sursumduction is effected by placing prisms, base up on one eye and down on the other, to test the capacities of the superior and inferior recti ; the minimum is 3 and the maximum 4 degrees ; penalties similar to the others. An amusing feature in this connection is that in cases where the so- called "muscle test" with double prism, or Maddox rod and the colored glass shows "exophoria," a weakness of the interni, according to them, the Duction test always shows the same muscles too strong; and when the same test shows "esophoria," or too strong interni, the duction test proves them too weak. More proof that their 'phoria story is the reverse of what they claim. "It is to laugh." The "optometrist" is not authorized by "law"' to operate, hence he pre- scribes prisms, as do also some oculists. But if either were required to demonstrate, theoretically or practically, the physical or physiological value of prisms they could not do so, even were their lives at stake. Another fad is the "Dot-and-Line" Test. They take a small card and make a dot on it, place the double prism before one eye, the other being covered, and have the patient find two dots, in a vertical position ; then when the other eye is uncovered it sees a third dot. If it is exactly in the middle of the space between the other two, the eyes are o. -k. ; if the third dot is seen on the left by the right eye, they say that eye is turning out ; if it is seen to the right,, the eye is turning in. In the first instance it is said to be from weakness of the interni, and in the second it is weakness of the externi. Then they make a second test with a line drawn through the dot, when, in many cases the third dot is seen on the line when it was not in that position before, because the right eye had something to guide it to the place. As a matter of fact the test is all bosh, because the muscles are not being tested at all. It is merely their voluntary nerve supplies which are being tried and the symptoms are interpreted wrongly, because: First, both eyes are equally involved : second, in the first instance the supply to the interni exhibited strongly on account of having no guide to tell when to stop con- verging, and it means a good supply, while the outward deviation is because the nerve supply is too weak. They have the foolish idea that the objects seen by the eyes in this and also in the "muscle test" deviate in a direction opposite to that taken by the eyes, when the reverse is true, as we have shown elsewhere. One thing few prism writers and users know is that the angle of deviation caused by a prism is only about one-half as many degrees as the prisms used. The exact amount may be found by multiplying the degrees of prism by the excess index. CHAPTER XXI. Heterophoria, "Muscular Insufficiency," a Nervous Exhibit. Treatment. Othophoria means correct tending of axes. Heterophoria means incorrect tending of axes. Esophoria means convergent tending. Exophoria means divergent tending. Hyperphoria means one axis tends above the other. Hyper-esophoria means a compound tending. Hyper-exophoria means a compound tending. Cyclophoria may be present with either of the above or alone. ("See special chapter on it.) An alleged "authority" says : "We must confess that our knowledge as regards muscular asthenopia and insufficiency of convergence is still in its infancy. The nature of this affection is still obscure, and trustworthy observations of the results of operations, with a view to cure it, have been neither numerous nor in accord with each other." Then he indulges himself in a long dissertation on "the absolute or relative weakness of the adductors or upon their insertion." Not a word about nerves. There is a reason for this. It is to be found in the following diagram : Xatural Therapy. . Artificial (Air Nitrogen Chemical. . . . Oxygen Water McCormic Salts Medical Baths Mechanical. . ( Drugs Physiological . . . ("Prevention". . . Exercise. . . . Systemic. . . . Mental "Vaccine". . . "Antitoxins" College Methods The "Cure" ... "Specifics". . il.... Surgery , {Commercial "Tonics". . . . Individual. . . Trust Old School Necessary Repairs Relief.. Methods There is a duality in therapy as in all other matters. The two legs are Natural and Artificial. The old schools are addicted, hopelessly it appears, to the latter. Neurology is founded upon the former. The old schools have their "muscle" test, their "duction" test, their "dot-and-line" test. The first is the same as our Static Nerve Test, that is the double prism or Maddox rod on one eye and a colored glass on the other. But they do not use it correctly. 182 A SYSTEM OF MATURE MEDICINE First, they assume that if the red glass is on the right eye and the red light, at fifteen or twenty feet distant, is seen at the right, it indicates an inward tending of the right eye, from weakness of its external rectus muscle, when, as a matter of fact, this is absolutely false in every particular. Both eyes are tending, both are tending outward, and it is not from muscular weakness, but is from a weak general nerve supply, exhibiting through the internal recti of both eyes. It is not an "affection" any more than headache is an "affection." It is a symptom to guide us toward a cause. Second, if the red light is seen at the left, they "diagnose" the right eye is turning out, from weakness of its internal rectus. This is wrong. Both eyes are turning in, from nervous irritation, spasm, exhibiting through the internal recti. This exhibit is always accompanied by tonic spasm of accommodation which conceals much of the hyperopia. This is easily proved by using strong plus spheres as temporary lenses, together with rest, sleep, baths, etc., until the general nerve supply is built up and the spasm breaks down, when the "exophoria" (really esophoria) is gone and even "esophoria'' (really exophoria) is exhibited sometimes, while the plus lenses accepted, with normal vision, are often several times as strong as at the first test. They are equally wrong in "hyperphoria" and the compound "affec- tions." To be right the student should reverse all of their statements as to the direction of deviation, and remember that both eyes are always involved, that it is not "muscle weakness" in either instance, but is spasm of the nervous system in convergence, weakness of the same in divergence, and an erratic distribution in the compound exhibits, due to irritation or weakness of the nerve supply, a matter to be settled by other symptoms. Their "duction" test was devised by the "commercial" surgeon who was so eager to operate for the fee that when the "muscle" test showed orthophoria he could still find an excuse for operating. This test comprises "adduction," "abduction," "sursumduction." The first consists of placing prisms, bases out, before the eyes, the patient looking at a digtant light, and if he can overcome 20, or up to 24 degrees, and see singly, his internal recti are all right ; but if he cannot overcome as much as 20 degrees, the "muscles" are too weak, and the externi must be cut. If he can overcome more than 24 degrees and see singly his interni are too strong and must be cut. The second test is with prisms, bases in, or toward the nose, and the test is on the externi, their minimum is 6 and maximum 8 de- grees ; if they are below 6 the interni must be cut, and if they overcome more than 8 degrees the externi must be cut. The third test is for the superior and inferior recti, and one prism is base up, the other base down ; if the muscles under the apexes of the prisms cannot overcome as much as 3 de- grees, their antagonists must be cut, and if they overcome more than 4 de- grees they must be cut. It is easy to see how prolific a source of revenue such a "test" can be made. When the student tries the "muscles" in this manner and finds how they can be trained to adapt themsleves to almost any amount of prism, base out, and that the "abducting" and "sursumducting" range is very limited; then considers the normal daily demands for each, respectively, it HETEROPHORIA A NERVOUS EXHIBIT 183 will be easy to see why the author quoted had to report that "trustworthy" observations have "not been in accord with each other." I once had in my class a physician who showed such weakness at each of the three tests that the indications were all of the "antagonists" would have to be cut. I wrote one of the enthusiastic "professors of duction tests" and inquired respectfully which muscles should be cut. He did not reply. I didn't cut any and the doctor is all right to this day. The fact was the man was presbyopic and growing old, hence could not have exhibited up to any youthful standard of nervous demand. Third, if the first two "tests" fail them they have the "dot-and-line" scheme, which is a dot on a card, held a few inches from the face, the double prism on the left, eye, the other being covered, and when the prism eye sees two dots, vertically, the other one is uncovered, and if the dot seen bv it is at the left of the others, the convergence is weak, so the externi must be cut; but if it is at the right, convergence is too strong and the interni must be cut. There is a saving possibility, however, in a second test with a line drawn through the dot; then, when the second eye is uncovered, if it sees three dots on one line, no cutting is needed, but if the single dot and line are at the left, it is "insufficiency" of the interni, and if at the right it is "insufficiency" of the externi. The whole test is a farce, and they are wrong again in their "diagnosis," (which means two guesses.) When the left eye has fixed on the two dots at close range, both eyes are converging, as can be seen readily; but the cov- ered eye, having nothing to guide it, converges too much, if the patient is young and vigorous, so that when the eye is uncovered it sees the dot out of line at the left, or, .if old or weak, it will not converge enough and will appear at the right, just the reverse of what they "diagnose." Then, when the line is added, a vast majority will adjust their eyes at once to all three dots on one line, because the controlling center in the brain has something to guide it in stopping convergence at the right place. If there is an irritated nervous system the left eye will see two dots on its line and the right will see one dot on another line, at the left; or if there is weakness it will see its line and dot at the right. But in no instance is there any warrant for operation or "prism exercise;" they are all symptoms of causes which are to be found in errors of refraction primarily, and in several pos- sible contributing ones, secondarily. The various "phorometers" are all based on these alleged principles, hence are worse than worthless, because they mislead a class of practitioners who will not read this book until the Christian adopts "The Age of Reason" as his rule and guide, and the "Christian Science Healer" has ceased to chase "material" dollars. Operations for heterophoria are criminal. Prism exercises are foolish, and prescribing prisms in correcting glasses is a display of ignorance of anatomy, physiology, physical laws and ophthalmology generally which is disgraceful. The true Ophthalmologist learns his business, Theoretically and Prac- tically. Then he is able to find causes and remove them without drugs, 184 A SYSTEM OF MATURE 'MEDICINE operations, prisms, or any other nonsense. Nature will do the rest if patients will afford the opportunity under proper instructions. Our static test is solely for finding the state of the nervous system by putting the eyes in such a situation that the controlling center, in the brain, is not in command; then the exhibit is an involuntary one and is fairly reliable. However, we do not reach final conclusions without further tests, which are described in their proper place; and, after having completed our analysis we have never found any reason for prescribing prisms or opera- tions. We would as readily prescribe headache powders for cases exhibit- ing that symptom. I know it stirs up the wrath of the old-line practitioners -to be criticized, but when it is so easy to prove they are wrong, and to prove by their own works that they have merely reiterated one another's assertions, evidently without making any critical tests of the propositions, it becomes a necessity to expose them. The little fish who ape the "authorities" are even more virulent than the big ones they are the "optometrists" who have been made "professional" people in a night by acts of legislatures. My sympathy is with the public. We are all liable to errors, which are pardonable; but to put assertions against mathematics is foolish, hence unpardonable. CHAPTER XXII. Heterotropia, Strabismus, Squint, Cross-Eyes. Treatment Therefor. Orthotropia means eyes' axes parallel at rest. Heterotropia means eyes' axes crossed. Esotropia means convergent axes. Exotropia means divergent axes. Hypertropia means one axis up, one down. Hyperesotropia means a compound turning. Hyperexotropia means a compound turning. Normally the eyes, when at rest, or in their static condition, have their axes parallel. This is orthophoria, also orthotropia. When they are not parallel it is heterophoria or heterotropia ; the former if the deviation is imperceptible to the observer, the latter when the turning is apparent. Cross eyes mean crossed- axes, and it is the only correct term to use. The several names in the title of this chapter and to be found in books are merely "scientific" expressions for use by those who cover a lot of ignorance with a lot of bluff. If the axes turn toward each other, horizontally, it is convergence; ii they turn from each other, horizontally, it is divergence; if they turn up and down but neither toward nor from each other it is hypervergence ; if they turn toward each other and up and down it is hyperconvergence ; if they turn from each other and up and down, it is hyperdivergence. The first three are simple turns, the first exhibiting nervousi irritation through the third nerves branches to the interni ; the second exhibiting nervous weakness through the same channels; the third may be spasm, or weakness of .the nervous system and it is exhibiting through the third nerves and the superior and inferior recti. The last two are compound turns: the first of which indicates nervous irritation because of the inward turn, but a ten- dency to weakness because df the up and down turns, while the second in- dicates weakness because of the outward turn, but a tendency to spasm because of the up and down turns. There is no difference of opinion between this writer and others in the matter of "diagnosing" the 'tropias generally, because even they can see the eyes are turning in, out, up or down. But in the details there is a chasm as big as the Grand Canyon of Arizona. "Authorities" define strabismus as: "That abnormality of the eyes in which the visual axes do not meet at the desired objective point in conse- quence of incoordinate action of the external ocular muscles." Then they 186 A SYSTEM OF MATURE MEDICINE subdivided the matter into classification as follows : "Alternating, one in which either eye fixes alternately; Concomitant, one in which the squinting eye has. full range of movement; Convergent, one in which the squinting eye is turned to the nasal side; Divergent, one in which the squinting eye is turned to the temporal side ; Paralytic, one due to paralysis of one or more muscles ; Spastic, one due to spastic contraction of an ocular muscle." They say, only one eye turns, usually, that hyperopes have convergence ; myopes have divergence ; that operation by advancement or by tenotomy is the only treatment; that paralysis is one cause, amblyopia another, a lack of equilibrium between accommodation and convergence another. They have a plan for "orthoptic" training at a "reasonable fee" per train to "pre- pare" patients for the operation or to find how much cutting is needed. The same general denunciation applied to them in the chapter on heterophoria applies here. There is but one exception, and that is obvious to any intelligent person : when there is divergence and one eye is blind an operation is permissible and even advisable for appearance. We insist that the primary cause of all cases of convergence is hyperopia, the accommodation effort to overcome the error is the secondary cause and systemic conditions are contributing causes. In quite a number of cases the latter act suddenly, as in the convulsions of whooping cough or other spasm- exciting derangement, or the same suddenness may be caused by weakness from acute, nerve-weakening derangements as the fevers. That amblyopia causes it we deny. Of course if an eye is amblyopic its connection with the controlling centers in the brain is not such as well tend to make it act co- ordinately with the other, hence it might be imagined a cause of the turn- ing; but that is not true because not only do emmetropes with one injured eye not have cross eyes, but ametropes with crossed eyes, one being amblyopic, straighten by our method almost as readily as if there was no amblyopia. The first case I straightened, twenty-four years ago, was, and is today, amblyopic to the extent he couldn't differentiate between a cow and a. street car with the bad eye. As strange as it may appear that boy grew up, took an old-school course, and is a rear rank member of the Medical Trust today. But his bum eye remains a testimonial to Neurology. Divergence is often the result of operation for convergence; sometimes from a general weakness of the nervous system, exhibited through the third nerves and interni, and accompanied by weak accommodation and other symptoms. It might come to a myope, but it would be very rarely and with contributing causes of importance. As, in convergence, hyperopia is the primary cause, accommodative effort the secondary one, with the other possibilities as contributing causes. Hypervergence is accounted for in the same manner and by the probability of intra-vascular obstruction putting pressure on a nerve sufficiently to shut off the current to superior or inferior muscles. As in the 'phorias both eyes turn. The reason one exhibits it all, usually, is that if the victim permitted both to remain converged or diverged or hyper verged he would see double and have difficulty in seeing clearly because the images would neither be on corresponding points of the two retinae nor would they be near the centers of the maculae, hence would be CROSS EYES AND TREATMENT 187 very indistinct. Therefore, in order to see clearly he fixes with one eye and forces the other to do all of the turning. This is easily illustrated in a nor- mal pair of eyes. Have such a person hold a finger one foot from the eyes and it. will be noted that he converges with both; now take hold of his finger and pull it over until it is in such a position one eye is looking straight away on its normal static line and the other will be seen doing all of the convergence for the finger distance. In cross eyes the person is merely looking at a distant object with the fixing eye and the other is exhibiting ail the turning of both. Or take a cross eyed person and have him fix with the eye the others say is turning and you will see a reversal that proves our story. When a case is presented, no matter which classification it belongs to, we first cover the fixing eye and ask the patient to fix with the other, with- out turning his head. If he can do it we are ready to proceed at once. If he cannot we put on temporary, -}- 3.00, bi-convex lenses, direct that they be worn constantly, and that he make frequent efforts to use the non-fixing eye; we may even order a patch worn over the fixing eye; hot baths, rest, proper foods, rotary exercises of the eyes, separately and together, stoppage of all close work, plenty of out door exercise. After he can fix with either eye at will the battle is half won; next he will begin to see double; then is the time to let down a little on the fogging to encourage the controlling cen- ters to work. In some cases several changes of lenses are necessary during the period of treatment ; but that is one of the things we are paid for. The reason for the failure of our imitators in this work is their ignorance of the laws governing such matters and it is not possible to give them in a book; it must be done clinically; but two points can be made emphatic, namely: They do not correct all of the hyperopia, and they do not know how to find the contributing causes. As each case has its own peculiarities in the latter respect it can be seen how impossible is the proposition to de- scribe them here. Our procedure is the same for convergence and hypervergence. For divergence we fog the fixing eye the most, as in other cases, but we under- correct the non-fixing eye a little leaving enough hyperopia to set up some accommodation and convergence, unless the patient is too weak ; then we would, of course, build up the system first in the usual Neurological manner, after which the rest is easy, except in the rare cases of divergent squint with one eye amblyopic, when, if we could not develop vision enough to help us, we would not continue treatment. In all such cases patients are told of the odds against them at once. In the matter of fees: It is worth $100.00 to straighten a pair of cross eyes and anyone who does it for less beats himself. Those who get more earn it if the person is able to pay it and appreciates what it is worth to him. Some patients will say: "I can have an operation for $50.00." We reply: "You ought to get it free, or at most for $5.00, because it only requires two minutes of the surgeon's time and you take all the risk of cocaine poisoning, of blood poisoning from other causes, of failure, and you have nothing to protect you. The oculist will not guarantee a cure, neither will he guarantee you against harm. We will do the latter. He will not pay any attention 188 to your general condition, which is often a very important feature. We take weeks, sometimes mcmths, to get patients in shape. If the oculist's clip is worth $50, our method is worth $5,000. It is a crime to cut the muscles when only the nervous system is at fault. The use of prisms is foolish because they have no possible chance to work. It would be as intelligent to give medicine to straighten the eyes. Some rascals have advertised to straighten cross eyes with "oils." etc., and people took the bait. Barnum made a famous remark which applies to all such, both advertiser and victims. We offer a rational proposition, and we feel that we and our graduates are entitled to remuneration commensurate with the value of our services. The Ophthalmoscope. A Pterygium. A Central Cataract CHAPTER XXIII. Alleged "Diseases" of the Eyes. Their Causes and Treatment. So-called eye "diseases" are given great amounts of space in the text books, and alleged text books, which they do not merit. In every one of them, while we find abundance of "therapy" in the form of nitrate of silver, sulphate of zinc, mercury preparations galore, atropin, leeches, and opera- tions for which it is- frequently admitted they have no reason, we find noth- ing whatever about errors of refraction as even possible causes. The oculist has gone mad on "infections" with "bacilli" as causes, and he has about fifty- seven varieties of the latter. It is the purpose here to eliminate as much of that stuff as possible. Unfortunately, we have to refer to some of it in order that our readers may know what others mean when they refer to the various conditions by the, names the writers have given them. The very fact that so many of these alleged "diseases" have been pro- nounced incurable by the authors referred to is sufficient practical evidence that they must be wrong in their diagnoses. Theoretically we have the evi- dence that all ills, save those which come from injuries, are due to a com- paratively limited number of causes. Speaking generally, all possible causes, including accidents, may be classified under ten headings : congenital, infection, malnutrition, physical shock, mental shock, physiological strain, mental strain, habits, occupation, atmospheric influences. While some eye troubles may be congenital, some from infection, and some from physical shock, at least ninety per cent of them are products of physiological strain, due to the effort of accommodation to overcome hyperopia. We shall undertake to prove by the following pages, and the practices of the readers thereof, that the books referred to are wrong, that the applica- tion of drugs is dangerous, and that the persistent practices of oculists along old lines is conclusive evidence that they are either so dogmatic they do not want to learn or so criminally commercial that they cling to willful mal- practice for the dollars there are in it. We shall show that graduates from our school, and others who employ the methods described herein, have a wider field of practice, hence a more liberally remunerative one, because they are taught to take into consideration not only the effects of errors of re- fraction upon the eyes themselves, but upon the general system ; and they are also taught how systemic disorders may be contributing causes to eye troubles when the errors of refraction are the principal cause. We shall show that by giving attention to both classes of causes we accomplish, with- 15)0 A SYSTEM OF MATURE MEDICINE out drugs or operations, not only what oculists have failed to do, but what general practitioners have been baffled by. Among these are such general disorders as amenorrhoea, dysmenorrhoea, menorrhagia, indigestion, con- stipation, skin eruptions, headaches, and a great many other nervous de- rangements. It is our contention that the human body, and all of its parts, present Natural chemical and mechanical problems by reason of derangements and disorders ; but we have been unable to find any reason why we should em- ploy artificial chemical combinations at all, and we find very few occasions when it is necessary to resort to operation. Our successful practice for over twenty-five years has demonstrated to our satisfaction that our theory is correct. We have no dogmas, nothing but our philosophy (love of truth) to guide us, and we have learned to trust it implicitly. This does not mean guessing at a proposition and calling it natural. We figure on everything and do not accept it until we have proved every point by our double check system, which prevents the possibility of error. Eye disorders are of several classes. First we have the external exhibits. Second, the internal ones. Again we have those in which the symptoms are acute, with inflammation externally and pain internally. Again we have the external swellings, as puffing of the lids, and growths, such as tumors and pterygiums. W.e have those accompanied by painful vision, and those which are not so attended. We have those in which there is internal vascular dilation, and those with a decided deficiency of blood supply. The internal exhibits are studied through a knowledge of the anatomy and physiology of the eyes, and with the aid of the ophthalmoscope. ' Our treatment may be given in advance for all conditions : First, we give at least temporary correction of errors of refraction by putting on more -f- sphere than is needed in all cases where we are unable to approxi- mate the exact correction ; second, in cases of external inflammation or symptoms of internal ones we order absolute rest from all close work, and direct the patient to remain in-doors where the temperature is even, sleep as much as possible, apply hot water to the face, and even take hot all-over baths if possible, followed by the instillation of cold salt water, (about a heaping teaspoonful of salt to a glass of water), if the inflammation is external ; third, we regulate the habits of diet, and particularly the use of intoxicants and tobacco. Fourth, we give instructions to return when the inflammation is reduced, or the pain subsides, which should be in about a week pos- sibly less. Slight injuries to the eyes should be let alone, except to remove any foreign particles that get under the lids, and remain in-doors until they heal, using salt water injections and keeping the eyes closed. A laceration of the conjunctiva will heal in a few hours if let alone. For the more severe in- juries patients should be sent to hospitals where they can have surgical care, and let those in charge assume responsibilities we do not care to. It is no credit to any practitioner to lose a case, and our universal success is assured by our refusing all cases where we are not sure we can win. We are per- fectly willing to accord praise to the orthodox surgeon who exhibits skill ALLEGED EYE DISEASES 1U1 enough to save even the stump of an injured eye, so that an artificial one will be scarcely noticeable. The eye lids are formed by the tarsal cartilages. They include the orbicularis palpebrarum, the tensor tarsi and the levator palpebrae superioris ; they contain the Meibomian glands and the ducts therefrom which pierce the tensor tarsi, having about thirty openings on the edge of the upper lid and half as many below ; they are lined by the delicate membrane, the con- junctiva, which also covers the front of the eye ball. The third nerves, which operate the accommodation and nearly all eye muscles, also control the openings of the Meibomian ducts, and, in the excessive labor required by hyperopia the entire nervous system becomes irritated, over-heated, cramped, and this spasm extends to these ducts, interfering with the discharge of the sebaceous matter, or salve, which is secreted by the Meibomian glands, so that the edges of the lids become dry and scaly; or there may develop cysts or styes ; or, the edges of the lids may become puffed, with heavy discharges during sleep, and a drying of the matter, causing the lids to stick together in the mornings. This is readily removed with hot water and a soft cloth. Sometimes the edges of the lids double on themselves, turning outward, ectropion, or inward, entropion. Sometimes they develop pea- like tumors, chalazions. Sometimes there are to be found under the lining of the lids granulations, because of the hardening of matter which should have been discharged by way of the Meibomian glands and ducts, but which has accumulated on account of the closure of the ducts. This granulation is known as "phlyctenular conjunctivitis," "granular con- junctivitis," "trachoma," etc. The books referred to above describe it as "conjunctivitis catarrhalis acuta," "conjunctivitis chronica;" "conjunctivitis gonorrhoica," "trachomatosa," "eczematosa." And they claim it is all due to bacteria. Nevertheless, we take all such cases, and with our system of general treatment, we have fine results all the time, even with "herpes zoster," which was never known to yield to local treatments, but which we reach by removing the causes. Ptosis, or falling of the lids, is treated by others operatively, and they leave the eye with inability to close the lids, while we fix it without operation and leave conditions normal. Conjunctivitis is, literally, inflammation of the conjunctiva, the mem- brane which lines the lids and covers the front of the globe. The palpebral section has already been referred to. The part that covers the front of the globe is called the ocular conjunctiva, which fits the globe tightly, and is not so liable to exhibit the granular deposits as the palpebral division, for two reasons. First, there is not the lymphatic circulation there is in the other. Second, the compactness of the structure would prevent ; but occasionally there are such deposits even here. The main features are the connection with the internal eye, through the canal of Schlemm, which surrounds the cornea at. its margin, and which sometimes becomes injected from pressure within the eye until it appears as a bright red ring. This will be mentioned again in referring to "Iritis." The lachrymal apparatus begins at the upper outer corner of the orbit, in a depression of which lies the lachrymal gland which lubricates the eye by way of several little ducts controlled by branches of the third nerves ; in cases of hyperopia and the accommodative effort to 192 overcome it, when the spasm stage is reached these ducts refuse to deliver, so that the eyes become dry and itchy from friction; in Nature's attempt to relieve this the blood vessels of the conjunctiva become injected. Over in the nasal angle of the lids there is a prominence called the "lachrymal papilla," highly vascular, in which are little punctures which lead to the lachrymal canal and nasal duct. Sometimes an ordinary cold will be suffi- cient to set up a disturbance, and when the vessels of this lachrymal papilla become congested it closes the little punctures so that the tears cannot pass out in the ordinary manner, hence overflow on the cheek. This overflow is called "epiphora." It may also come from another cause, viz : when a per- son's nerve supply is weak the mouths of the ducts from the lachrymal glands relax and flood the eyes with tears in greater quantity than can be carried off, hence they overflow. Returning to the congested lachrymal papilla in which there sometimes develops a tumor or cyst from starchy deposits in the blood presenting a very angry appearance which has fright- ened patients and doctors needlessly : doctors have named it "Dacryocys- titis," and that of course adds to the patient's fright. Sometimes this con- gestion extends into the vessels of the conjunctiva and is directed toward the oornea, developing such a vascular thickenmg that it looks like a little muscle with a translucent point on it something like a finger nail a sort of ad- vance guard, which pushes on ahead of the injection, and when it gets up over the cornea in front of the pupil, it will of course obstruct vision, because it is not transparent. This growth is called a pterygium, meaning, literally, a little wing; some doctors have "diagnosed" it as cataract, which is foolish because cataracts only form in the crystalline lens. The old way of treat- ment for pterygium is to dissect it away, but this does not remove the cause and it returns. Our method is, in addition to the general treatment described in the beginning of this chapter, the vigorous application of strong salt water with an atomizer; the astringent quality of the salt combined with the cold empties the vessels and prevents their being refilled, because we have the errors corrected and other causes removed, so that in due course of time Nature restores normal conditions. Some express doubts about this because the habit has been to assume that when things go wrong Nature gives up, but anyone who has seen Nature handling a boil, getting rid of the "core," then healing the opening, nearly always without leaving a scar, will be reminded that Nature knows how to do the work. Everyone should be cautioned against allowing any such conditions to develop to the hyper- trophic state, because the more malignant they are the longer it takes to handle them, and a "chronic" case, that is, one which has been neglected or mistreated, is liable to develop a net-work of vessels all over the cornea, and, as it is a sore, it will naturally develop ulcers, the ulcers produce scars, and years will be required to reabsorb such tissue ; indeed it may never be ac- complished. This net work is known as "pannus," and the treatment for it by the old schools has been the use of caustics, such as sulphate of copper, which treatment is sufficient to produce ulcers, and to intensify them if they are present. All such cases if treated in time by our methods, the patient remaining indoors, are relieved without possibility of injury, and usually without leaving scars. This is always the case if we get them early ALLEGED EYE DISEASES 19! enough. Patients are always frightened, sometimes until they are "sick at their stomachs," and they are usually hard to handle, because they have an insane desire for drug treatment. If they insist on it, send them to the other fellow, and tell them to never return, no matter what happens. The books tell us that most of these troubles are gonorrhoeal. One Dr. Fuchs gives the following childish explanation : "The poison can be introduced into the eye from the genitals directly, generally, because an individual (whether man or woman) affected with gonorrhoea touches the eyes with unclean fingers after these have been in contact with the genitals." How marvelous it may be done either by a man or a woman ! Ophthalmia neonatorum is the conjunctivitis exhibited in the new born from a local infection, by uncleanly delivery, or it may be from atmospheric influences, and for this reason the old schools recommend that a strong solution of nitrate of silver be used in the eyes immediately. This is criminal, although not legally so regarded. A good hot bath, followed by the in- stillation of cold salt water can do no possible harm, and no infection, bug or otherwise, can survive in salt water. The so-called diphtheric and eczematous conjunctivitis are due to errors of refraction, associated with systemic disorders, and they are not amenable to treatment with drugs, but yield readily to our general system, including special diets. There are oc- casions when the ocular conjunctiva is injured by accidents, but a*s has been remarked before, any ordinary laceration will heal itself in a few hours if let alone. The Cornea and Sclerotic constitute the outer coat of the eye and are as tough as leather; the cornea gets its name from the word "horn," and the word "sclerotic" means hard. Neither of these parts of the eye has any nerve or blood vessel worth mentioning, except that around the edge of the cornea, including the canal of Schlemm, there is a fairly good supply of each, and the sclera is pierced by vessels about the equator and posteriorly. The cornea is constructed of several layers, some of them cellular and some fibrous, and, being live tissue in contact with the ocular conjunctiva, there is a possibility of corneal structure being involved in cases of ulceration, but we have our doubts whether this would ever occur if escharotics were not used. The books devote much space to keratitis, inflammation of the cornea, and sclerotitis, but without any reasonable ground for it. They also say that there is "photophobia" (painful vision) in conjunctivitis, when any- one ought to know that painful vision should not occur from such a cause, but only from inflammation of the retina. Of course, conjunctivitis might be present at the same time, but it has nothing to do with the painful vision. There are some things that happen to the cornea, such as assuming a con- ical form called keratoconus ; then there is a sort of degeneration of the tissue which sometimes occurs, called "keratomalacia," in which it assumes a semi-transparency, and these are both conditions for which no one has yet been able to do anything good. The Iris, Ciliary Body and Choroid constitute what is called the uveal tract, because when this layer is exhibited alone it is about the color and shape of a grape. This is a highly vascular and nervous layer, excepting the iris, and in the ciliary body lies the mechanism of accommodation which 15)4 A SYSTEM OF MATURE MEDICINE operates the crystalline lens. In the chapter on Anatomy of the Eye will be found the anatomical details. Physiologically the effort of accommodation to overcome hyperopia being such an unusual demand upon the nervous system, and meeting with the resistance it does in the suspensory ligaments, there is a heating, the same as in an electric battery, under similar condi- tions, and in order to keep the eye cool an excessive amount of blood is sup- plied automatically. This not only causes increased tension of the eye ball, but the cramp which often occurs in the sphincter nerves causes pain. The old schools have denominated this "rheumatism" of the eye. It is really neuralgia (nerve pain). These are several possible results, one is that the congestion and overheating develops a hypertrophic condition, which, if not relieved, may reach a stage where it breaks down, that is, atrophy begins, and in such cases the whole interior of the eye collapses, destroying it. Hap- pily, being well protected from outside influences this does not often occur. The preliminary stages indicated by the pain from tonic spasm, and in- flammation of the retina, developed sympathetically, together with painful vision cause the sufferer to seek aid, and when the errors of refraction are corrected the cause is removed, when, if a reasonable time is given for the inflammation to subside, normal conditions will be resumed and there will be no further, trouble. The first stages are all included in the word "cyclitis," but when the extraordinary stage is reached, it is known as ''glaucoma. 5 ' The old schools ''diagnose" glaucoma when it is simple cyclitis, just as a young doctor diagnoses every case of bilious fever as typhoid. Almost any old doctor will say he had more cases of typhoid fever the first year of his practice than he has ever seen since. So it is with young oculists. They find an abundance of glaucoma where we older ones only find cyclitis. There is this difference, however, that all of the old-school oculists young and old 'find the glaucoma. It is only Neurological doctors who differen- tiate, and we declare that a genuine case of glaucoma cannot be cured any more than life can be restored to a dead person. The same people are always finding iritis, and they have eight kinds of it. Viz: syphilitica, scrofulosa, gonorrhoica, rheumatica, tuberculosa, acute infectious, disorders of metab- olism, traumatica. As a matter of fact, there is very little iritis, because the iris is scantily supplied with blood and nerves, and because it hangs in a solution of salt water, the aqueous humor. In a preceding paragraph the canal of Schlemm was referred to, and instances of its injection with blood, an overflow from' the ciliary body. This exhibit is the old-school reason for diagnosing iritis. It always means cyclitis, and instead of being treated with atropin and other drugs, the proper and only treatment is that described above as our general treatment. It is true that the administration of atropin would have a tendency to paralyze the nerves of accommodation, and, incidentally, give temporary relief, but that is not removing the causes of trouble ; and, as soon as the effect of the drugs disappears, the trouble begins again. This is why the old-school doctors have "recurrent" cases. We never do. Their treatment includes bleeding with leeches, confining ALLEGED EYE DISEASES 195 in a dark room, colored glasses, etc., all of which are harmful because they are not rational; can do no good, hence do harm. The Crystalline Lens is the adjustable part of the dioptric system, and to be useful, must remain transparent. It is subject to the development of an opacity called cataract, a name that doesn't fit it, which is of four varieties : congenital, present at birth, when the lens is as white as ivory ; traumatic, caused by injury, may develop in a night from a blow on the eye ; systemic, one which develops from derangements of body chemistry, and may occur at any age ; senile, that which is incident to old age. The latter is always found to have a history of hyperopia, and it is possible that it is due to the heating of the entire internal eye. Sometimes this opacity comes on gradually, and in the form of a spider's web ; sometimes it begins in the middle of the lens and gradually spreads outward until it involves the whole lens. Sometimes it is soft and sometimes it becomes hard. Some- times it begins at the anterior pole of the lens; sometimes posteriorly; and sometimes around the edge. As a rule they develop slowly, and may be in one or both eyes. Again, in very old people who grow suddenly fat, they first develop emmetropia where they have been hyperopic, so that they leave off their distant glasses; later they leave off their reading glasses, and examination shows they have become myopic, yet the lens remains transparent or very slightly cloudy; occasionally it becomes opaque. In such cases it tells us that dissolution is taking place, and that the patient has not long to live. In cases of slow development they may live many years. The old treatment was operation, and in many cases that is the only thing, but some cases have been treated successfully by the instillation of a drop or two three times a day of succus cineraria maritima, or oil of thuyit occidentalis, or a : saturated solution of common salt, or undiluted lemon juice, all of which cause an intense burning sensation for a few minutes, during which the eyes should be kept closed to keep the tears from washing the application out. We have seen some very excellent results, and we have seen cases where it failed utterly, which proves again the uncertainty of anything applied as drug "remedies" are employed. Operation is the only sure thing to get rid of the cataract, but this does not mean it is sure to give vision, because the retina may be involved. It is advisable to let them alone as long as one eye remains good. There is no possible harm can come from this, and there is absolutely no pain during the development of the cataract, or after it is developed, because there are no nerves in the crys- talline lens. The operation for cataract is painless, so that those who find it necessary need have no fears on that score. After operation, of course, glasses will have to be worn in order to have any distant vision, and a second, stronger pair, will have to be used for near work, because the power of accommodation is gone. In cases where one eye is injured, and cataract develops, the best thing to do is to let it alone and give attention to the other. One case in my experience was that of a stenographer at the Stock Yards who attended a wake, and a frivolous young man sailed a hat across the room, which struck her in the eye, so injuring it that a cataract developed the next day, and there was, incidentally, a considerable external inflamma- tion from the injury. After a few days her family physician brought her to 196 A SYSTEM OF MATURE MEDICINE me, bewailing the loss of her two eyes, as she could not see to get around without help. After questioning I decided to investigate the uninjured eye, when I found she was myopic about six units ; I gave her a correction with almost normal vision, showed her she had never been using that eye be- fore, which eased her mind, and she has been content to forget the cat- aractous eye. An operation would have been a very doubtful one in that case, and if the eye had been usable afterwards, it would have required a very strong -f- lens, while the other one, using a strong , would have given her a very queer appearance indeed. The Vitreous Humor is liable to opacities, which exhibit in the form of floating specks called "muscae volitantes." We have found these attended by history of very wrong living in the younger people, that is, they indulge in too much sweet and starchy food ; but by correcting the errors and chang- ing the diet we get good results very quickly. When they appear in older people it is an incident to the chemical changes of the body, due to age, and while we have secured improvement, we have rarely been able to eliminate them entirely. The Retina has been the subject of more slander than any other part of the body. In the first place, the macula lutea (spot yellow) of Soemmering is a fraud, there isn't any such place, except that -there is a field around the posterior pole of the eye which may be regarded in a general way as a spot, but it is not marked by any lines, colors, or anything else whatever ; in the text books it is pictured as a brown spot ; it is neither brown nor yellow, but is simply a pinkish color like all the rest of the retina. One noticeable thing about that field is there are no large vessels, rarely any large enough to be distinguished. Fig. 110 shows a normal retina, the optic disc showing a well defined edge, the vessels meeting in the center and disappearing. The lighter ones are arteries, and the darker ones, veins. This was drawn from the right eye of a normal person, hence the macular field is on the left side of the disc as we look at it, and may be said to include a space, beginning at the edge of this disc, H times the diameter of the disc ; in the center of it is the posterior pole of Fig. no the eye. The fovea centralis is at the pos- terior pole, and not at a point 5 degrees outside of it, as some have asserted. Many people have been deceived by the books, which have led them to believe that the pictures of retinae are photographs. I doubt very much if there ever was a photograph taken of the eye, with one exception, viz., my own, and we didn't get a good one then. I made and patented a machine for the purpose and for use as an indirect ophthalmoscope, but have never recom- mended it, because the direct method is much better; indeed, nothing can take its place. The reason I undertook the photograph proposition was a wild-eyed story that was printed in the Literary Digest fourteen years ago, purporting to come from Germany ; it pictured an apparatus, and it struck me as funny that any person pretending any scientific knowledge would perpetrate such a ALLEGED EYE DISEASES thing, because it had a half dozen batteries of lenses in it, and according to the drawings a picture would have been an impossibility. It was proposed by a German authority as a valuable thing to study the progress of "diseased" eyes. My machine consisted of a tube, shown in Fig. Ill, with a direct illumi- nation and an adjustable sliding arrange- ment, with a -f- 8.00 diopter bi-convex lens in it. With the aid of an assistant, I succeeded in having a picture made of my own retina, with considerable pain to my- self, enough to satisfy me that it would not be very pleasant to a person with a diseased retina. One difficulty is in get- ting the eye to hold still long enough to get a perfect picture. We tried a dozen Fig. 111 times before we got one. The Ophthalmoscope is for the purpose of studying conditions of the internal eye ; but not nearly so much for local "diseases" as it is for daily use on every patient, to note the quality and quantity of the blood which is circu- lating in the body, the size and number of vessels, which range in number from six or eight to thirteen good-sized ones. In some cases we find the number comparatively few, but of good size and the contents good. Normally the arteries have a distinct white streak down the center, occupying about one-fifth of the diameter, hence we say the blood is 80 per cent red. The blood is so nearly transparent that, if the vessels were square, we could scarcely see it, but as the vessels are round we only get the axial reflection because we are perpendicular to it alone. If the light streak occupies one-third of the space, it means only 66 2/3 per cent red blood, which is a low quality, and, of course, quantity. Practice enables one to become so expert in estimating the quality by this method that the slow process of counting corpuscles is done away with, and when others have made the count after us, they have corroborated us every time. There are generally two or more veins for each artery, and they are somewhat darker, because they carry waste from the body ; but in young and healthy children they have a distinct light streak, and the- only way we can tell the difference between them and arteries is that they are larger. There is a difference, too, in the showings of healthy people of differ- ent complexions, because in some there is more coloring matter than in others, but the operator soon learns how to regard these slight differences. Some- times we get surprises : patients will come with a fairly good external appear- ance, but when we examine them with the ophthalmoscope we find at once they are deficient in blood supply, not only in the quality and quantity of blood in the vessels, but in the number of branches exhibiting in the eye, which is a fair sample of the general distribution, and when we finally meas- ure the nerve supplies of such cases, we invariably find them below their dan- ger line. It fell to my lot to make such a discovery in my own brother, and according to the analysis of his case, he had less than six months to live, unless by strict obedience to instructions indicated, he might have regained his nor- mal status. Like a great many others, he could not believe it possible that 198 A SYSTEM OF MATURE MEDICINE anyone could analyze a case with such a degree of certainty; he had important business affairs to attend to, and he took the chance. He lived four months. In many other cases conditions shown by the analysis were startling, and like the one mentioned, the victims could not be impressed with the impor- tance of heeding the warning. They all died within the time predicted. There are two symptomatic points which must be regarded in every case, one being the quality of the blood, both arterial and venous, and the other the quantity, based upon the apparent supply in the vessels and the number of vessels compared with the average number found. Qualitatively, if the light streak in the arteries occupies one-fifth, we record it -)-. If it is more than that, we record it ; if the veins are so light colored that there is a pale streak down the center, we mark it -(-, but if the vessels are very dark we mark it , except in cases of very old people, when we expect to find both the arteries and veins somewhat below normal, viz., the light streak in the arteries wider and the venous blood darker. Quantitatively, we record the number of ves- sels found, specifying the number of arteries and veins separately, and make reference to the calibre. Occasionally we have exhibits of retinitis. It begins at the edge of the optic disc (sometimes called papilla, sometimes the blind spot), and extends radiantly outward, the congestion sometimes being intense enough to obscure the edge of the disc, as shown in Fig. 112. This was a case of so-called "Optic Neuritis," or "Neuro- retinitis," produced by reflex in dysmenorrhea. It is purely mechanical and is commonly called "choked disc." Note how dark and congested the veins are, and how light and empty the arteries. The primary cause was the accommodative effort to overcome hyperopia, which set up such an intense 'Fig. 112 general nervous spasm it involved the sphincter nerves of the os uteri, and when the additional pressure at the catamenial per- iod was added, it reacted and put the nervous system into a worse spasm, this time involving the sheath of the optic nerve, whicli also encloses the retinal vessels, and pinched so tightly arterial blood couldn't get in and venous blood couldn't get out of the eye ; there was also tonic spasm of accommodation, ac- companied by great pain. A patient had been told that an operation on the eye would be necessary (just what the nature of that operation was the pa- tient was unable to report) ; but having noted the special exhibit in the eyes at her menstrual periods for a considerable time she mentioned that fact, and while the oculist told her it had, no doubt, something to do with the eyes, he did not tell her that the menstrual trouble was due to the eye error in the first place. He did not know it. We found a high degree of hyperopia, and in two months had her all right in every particular, vision normal, and no pains whatever at her monthly periods. There are other cises presenting a similar appearance, except that the large vessels are neither empty or congested, but the inflammation is more wide spread ; they come from chemical changes in the body, and it is very important that they be looked after in a broader way than the Ophthalmolo- ALLEGED EYE DISEASES 15)9 gist can do, therefore, if no Neurologist is near, the patient should make the journey to see one, because while it does not always mean that form of toxemia commonly known as "Bright's disease," or "Album- inuria," it is very likely to be something of that na- ture. If, in addition to the inflammation around the disc there be yellowish patches, from the size of a pin head to much larger, as shown in Fig 113, it means kidney trouble in the second stage of progress. If, in addition to the inflammation and yellow patches, some of the patches are white, it indicates the third stage, and if there is the addition of black patches, as shown in Fig. 114, it indicates the last stage of so-called "Bright's disease." The Ophthalmologist should have nothing to do with either of the last two stages. It will do no harm to correct their eye defects, but that would not be sufficient to do much good in a general way. In what is commonly known as the "diabetic diathesis" the patient will complain of seeing float- ing specks before the eyes ; we may see nothing with the ophthalmoscope, although there is a prob- ^"^J^BP*^ Kiu; 114 ability we will find a dappled appearance of the retina. However, the float- ing specks are sufficient to tell us what the trouble is ; the patient is eating too much sweets, fats, starches, and possibly using liquor. A patient may have quite an acute retinitis so that vision is painful and there be no ophthalmoscopic appearance indicating it, but we know it is there and that only the nerves are involved. This is usually found in connection with ex- cessive accommodation to overcome hyperopia. In some cases of congenital syphilitic infection we find children going blind, and upon ophthalmoscopic examination we see streaks of retinal pig- mentation, or in other words, streaks of pigment are seen where the retina has become atrophied. This trouble begins anteriorly and works backward, and by the time we find it, it is too late to do any good. The books call this "retinitis syphilitica," but "retinitis" means inflammation, and we do not find inflammation in such cases unless the kidneys are involved, too, which is very rarely. Fig. 115 shows a plugging of a vessel, known as a "thrombolism" or "embolism." If the plug is at the end of the dilation, toward the disc, it is in a vein, and manipulation may help get rid of it. If it is at the other end, it is in an artery and manipulation would cause trouble : hence, the best way to treat such a case is to stop all work with the eyes, have the patient indulge in many hot baths and get thoroughly relaxed, when the P^g w iU work its own way out. Sometimes when the vascular walls are weak the vessel will burst and give an appearance like Fig. 116. The patient may be temporarily blinded, 115 200 A SYSTEM OF MATURE MEDICINE but in time absorption will occur, if the patient is careful. There are comparatively few retinal exhibits ol eye pathology, and hundreds of so-called "dis- ease" pictures are pure humbugs. We have seen some cases of anatomical freaks in which, while there were remarkable appearances of black, white, greenish and variegated deposits, there were no signs of there having been inflammation 'pig lie or other trouble, and the patients either had good vision or possibly none at all, but had always been that way. Referring again to "glaucoma" : It has been asserted by the old-school doctors that there are certain symptoms which always indicate that "disease," namely : patients complain of seeing halos around lights, tension of the eye- balls is hard (some say soft), there are increasing exhibits of manifest hyper- opia, and the ophthalmoscope shows a deep cupping of the disk, with some or all of the vessels turning in at the edge of the disk. Many years ago one of my pupils brought a case to the college, who exhibited all of the symptoms enumerated. He was a student at the Physio-Medical school on the West Side, Chicago, where the professor of ophthalmology had pronounced it a gen- uine case. Fig. 117 is a drawing I made at the time, and it is accurate. The young man who brought the case was also a student at the P-M, and had found first, .50 hyperopia, then 1.00 and finally 1.50. On account of the symp- toms, he referred the case to the professor; but after hearing his diagnosis and suggestions of enucleation, he brought the case to me. He had normal vision with naked eyes, and, having worn + 1-30 for several weeks, was in good condition to accept full correction, which I found to be + 2.50. It was a case of tonic spasm with some cyclitis and pain at first, both of which disappeared quickly with complete re- moval of the cause. I found, by questions that he had always practiced the habit of staring at lights, which accounted for the halos he saw ; ^^^^^^^^ his tonic spasm accounted for the pain and for the extra tension of the eyeballs ; his cyclitis naturally involved some retinitis and the variable vision h,e had exhibited before wearing glasses. The only conclusion with reference to the cupped disk was that it was an anatomi- cal freak. I met the man often during the next four years and he was all right. Since then I have occasionally met similar cases and have known many who had been told they had "glaucoma" who recovered very quickly under rational methods. In January, 1916, one of the students in our Department of Ophthal- mology met a man in a barber-shop who was wearing smoked glasses and whose eyes were inflamed and granulated externally and who complained of the light hurting his eyes. Upon questioning him it was learned that he had "trachoma" and was then suffering one of his periodical "back-sets," according to his oculist. Only that day, in the class-room, I had asserted ALLEGED EYE DISEASES 201 that the "trachoma" fad was worse than the "glaucoma" one, because there are more cases of it. The student took advantage of the opportunity to "try me out" as he expressed it. He boldly asserted the case wouldn't last a month under our methods. The man came around that evening and made an appointment for the next day. Examination revealed a "typical case" with the addition of a well marked ptosis. He had a pair of -f- .50 "toric" lenses, to be used for- reading only, and wore smoked glasses for general use. He said he had been treated for over thirty years. Naturally he was not in condition to be fitted with glasses;^ he was highly nervous, and vision was only 1 % - I put on + 3.00 temporary lenses, stopped work for a few days while he took hot all-over baths, hot towels to the eyes, followed by cold salt-water applications, plenty of sleep and wholesome food. In four days he reported the painful sensations from light had disappeared and the external inflammation was much reduced. Three weeks later he was dis- missed, sound as a dollar, wearing + 3.50 bi-convex spheres and reading the normal line on the test card. Exophthalmic goitre is a protrusion of the eyeballs associated with en- largement of the thyroid glands. It is a symptom of disorder, the causes of which are generally so obscure they have never been located. I have found that one of them is hyperopia, because many cases have yielded readily to correction of that eye defect and with the additional help of baths, diet and general hygienic measures the neck exhibit disappeared. My first case was about eighteen years ago, when a woman came to take a course in Ophthal- mology. She was about twenty-six years old, weighed about 180 pounds and was wearing 2.50 lenses, prescribed by a western oculist. She was a mother and had undergone a hysterectomy, after which the goitre developed. Her glands were both greatly enlarged and the eyes protruded decidedly. Examination proved her to be a hyperope of 2.50 instead of a myope of that amount, so that with her lenses on she was a hyperope of 5.00. In three months the exhibit disappeared and we reduced her weight to 140 pounds. I have seen her nearly every year since and there has been no signs of re- turn. Other cases gave equally good results, while some still retain par- tial enlargement of the glands, although they have suffered no inconven- ience therefrom. Progressive Myopia is one of the conditions which demand considera- tion in this chapter. It usually develops between the ages of six years and maturity; it is marked by high tension of the eyeballs, demand for increased power of the lenses at frequent intervals and the ophthalmoscope reveals a white crescent on the polar edge of the optic disk while the large vessels turn abruptly toward the nose before disappearing. It is due to systemic changes which increase the volume of the vitreous humor, putting such pres- sure on the posterior pole of the globe that there is a bulging (posterior staphyloma) ; this pressure and consequent bulging first stretches th% layers of the globe until it is too long on the axis for the original lenses and strong- er ones are required. If this condition is not arrested the final result will be that the retina, which has already been torn loose from the edge of the disk when the crescent is seen, will be destroyed entirely so far as the macular field is concerned. When that stage is reached the ophthalmoscopic view 202 A SYSTEM OF MATURE MEDICINE discloses the white sclerotic and fragments of the pigment layer, with some- times clots of blood from the torn choroid if the rupture is a recent one. Of course nothing can be done for such cases in the latter condition. If taken early the correction of the error of refraction, out-door life and proper food will stop progress permanently. All cases of myopia in children should be corrected carefully, using the weakest -- lenses that will give 20/30 vision and the above programme suggested. It is an aged axiom that "an ounce of prevention is worth a pound of cure." Epilepsy is one of the exhibits in children due largely to hyperopia as a primary cause ; the effort of accommodation to overcome the error involves such demands on the general nerve supply that other functions become dis- turbed. Indigestion is one, bed-wetting is another, mental irritability or dullness is another. If a child habitually exhibits excitability and temper, with bed-wetting look out for convulsions. Sometimes they occur soon after going to bed, after which the child sleeps soundly until morning. Others do not reach the stage of convulsion and relaxation until toward morning. Morning head-aches in children are indications that there have been convulsions during the night. The Ophthalmologist can reach the cause of practically all of such exhibits in the young; but when they are found in persons past the age of puberty it becomes a Neurological case and requires months to remove the causes so they will remain normal. Reference has been made elsewhere to the bad effects of chromatic aberration in "toric" lenses and in "fused" bifocals. In the latter the inset portion is of "flint" glass which has double the index of dispersion of the ordinary glass used for spectacle lenses and wholesale optical houses have announced they will not be responsible for the aberration, thus proving there have been many complaints. As to the "torics" one instance will be sufficient to show the damage which may be caused : Some years ago I had a case of anisometropia requiring 4- 4.00 for one eye and -f-- 8.00 for the other, which had been considered blind and had not been corrected. I ordered frames and had the lenses made as thin as possible, bi-convex, to avoid aberration and weight. The bad eye came along all right and in a few weeks was as good us the other; both practically normal. The girl and her father were highly pleased ; all was well. A few months later her father ceased speaking to me. He was a drinking man and I supposed he was tipsy so paid no attention to the matter. A few days later he began abusing me in the elevator of the building where we had our offices ; he said I had put his daughter's eye out. I told him to bring her in and 1 would replace the one I put out. That afternoon they appeared and both expressed them- selves vigorously. Then I began an examination. The first thing I struck was when I removed her glasses : I found they were skeleton "torics." I asked where she got them. She replied that she. saw the advertisement of an optician, (who advertises with a bird's beak to symbolize his name), and when she called to see him he told her they were the "last word in lenses." I told her I thought so too ; that she would better go and vent her spleen on him ; that I would have nothing more to do with the case ; and I showed her and her father the way to the door with the admonition to vacate and do it quickly. From experience with other cases I have no doubt that the ALLEGED EYE DISEASES 203 chromatic aberration gave her eye a set-back; it might have been repaired and it might not ; I took no chances under the circumstances and at once in- creased my fees so that when I take a case it pays me enough at the begin- ning to warrant it will stick to me to the end. Menstrual derangements are such a common exhibit from the nerve strain of hyperopia that parents should have their daughters' eyes examined by a competent Ophthalmologist at not later than the tenth year, so that the function may come on naturally. Amenorrhoea, dysmenorrhoea, men- orrhagia, respectively, no flow, painful flow and too much flow are the ex- hibits. They have puzzled the old-school doctors always, and the whole bunch have never done as much good with their tampons, curettements. etc., as any one of our graduates accomplishes every year. The old notion that pain is a natural incident to the function has been knocked into a "cocked hat" by our brand of Ophthalmology; and our Neurology even carries the war to the limit by eliminating the pains of parturition. Cor- rection of the eye errors, diet, baths, manual treatment and education of patients is our armament. It has always been taught by the doctors and the wise ones among the laity, that after the "change of life" in a woman, her physiological ills usually disappear; but they always add: "provided she gets through that period with her mentality intact." The proposition appeared reasonable be- cause it was backed by exhibits ; but when we observed that men with "grouches" parted with them at about the same age as the women, the thought came to us that the cause was not what had been claimed ; then when we found that by correcting the hyperopia and performing a few other easy, natural repairs on the human machines, male and female, we got all of the results formerly left to Natural infirmities, we thanked our heterodoxy and handed the evidence to our students. Quite frequently, in cases of nervous exhaustion, the sphincter muscles controlling the mouths of the lachrymal glands become so relaxed that the tears flow faster than the nasal ducts can carry them away. The oculists call this an operative case and pioceed to probe the ducts, sometimes even inserting tubes. It is not only an exceedingly painful procedure but it is absolutely foolish for anatomical and physiological reasons which any oculist ought to know : First, the structure of the tissue in the canals is similar to that of a sponge, for the purpose of absorbing a reasonable amount of fluid; then the processes of breathing, coupled with body heat, cause evaporation. Second, operation lacerates this structure and scar-tissue forms, which, not having the capacity for absorption the normal tissue had, makes it im- possible to accomplish good by operation. Putting in tubes is worse, be- cause, being foreign bodies, Nature endeavors to expel them by the usual process and hypertrophy ensues. The simple way to fix all such cases is to correct the hyperopia and build up the system, when the lachrymal glands will work normally. In cases of spasm of the nervous system the mouths of the glands often close too tightly and do not discharge enough fluid to lubricate the 204 A SYSTEM OF MATURE MEDICINE lids, and the eyes become dry, itchy and inflamed. The same treatment suggested for epiphora will cause relaxation and correct the xerophthalmos. The many phases of alleged "diseases" could not be given comprehen- sively in a book ; but if the practitioners who read will qualify and try what has been stated here, they will find their confidence in Nature growing, their success increasing and their worries decreasing. Too many physicians appear to be under the impression that ophthal- mology is a branch of medicine. When questioned they admit they acquired the belief because very little was taught about eyes in their schools and all of that was about eye "disease" requiring the attention of specialists. The joke of it is the specialists were their teachers. Another joke is : the teachers know nothing of real Ophthalmology; they go out and practice as medical specialists, using cycloplegics and the "code of ethics" to bunko a practice out of the field which should be taken care of by the general practitioner. As the old schools teach and practice it, ophthalmology is a fraud. As we teach and practice it, Ophthalmology is a system of practice as independent of medical practice as is dentistry. As we teach and practice Neurology, or Mature Medicine, Ophthalmology is a branch of it and a very essential one. As we teach our work to old-school doctors Ophthalmology becomes a root of their work and the most important one. Our Ophthalmologists are not practicing old-school medicine and violating "law" when they relieve human ills after the old methods have failed. Statutes which have been employed to persecute old-school competition have always proved boomerangs to the persecutors. We have a supreme contempt for any man or woman in any trade or profession who would invoke the aid of unfair "laws" to protect them against competition. We regard such conduct as a confession of incompetence which is disgraceful. CHAPTER XXIV. Objective and Subjective Methods Employed in Eye Testing. More skill is required to fit a pair of glasses correctly than to perform any major surgical operation ever attempted. Anatomy is practically constant. Major operations are performed under anaesthesia. Therefore surgery is simply a trade. Some surgeons are more skillful than others, just as some butchers are more "handy" with their tools than others. The surgeon does his work. If the patient survives it is her- alded as a "triumph of science." If he dies it is charged to "the shock of the anaesthesia," to "neglect by patient", to "the will of God", etc. Physiology is always an inconstant. The contention of oculists that cycloplegics are essential to good work in fitting glasses proves two things : First, that they do not know the physiological relations between the eyes and the general system ; second, as a sequence, they believe that when the pupils dilate and the accommodation is apparently paralyzed, the obstacles are all removed and finding the full correction is like neutralizing lenses. Their practices are more condemnatory than their theories, because : First, they do not practice what they preach, for they do not atropize more than one-half of the patidnts who patronize them; second, when they find patients do not "tolerate" full corrections after the effects of the cycloplegics have worn away, they weaken the glasses to suit the pleasure of the in- dividual, thus letting him fit himself, as he might do at a department store counter; hence little benefit is received, and sometimes actual harm is done by their giving lenses where -f- are needed. "Optometrists", not being licensed to employ drugs in their practices, have gone as far as they dared and profess skill with the skiascope, or mirror test, which they call an objective test, when it is actually the very worst form of subjective test, because, the intense light thrown into the eye by the mirror irritates the optic nerve and it communicates with the little devil inside, who controls the iris and the accommodative apparatus, with the effect that there is a first-class spasm in about two seconds, which remains either as a tonic or clonic exhibit, during the entire procedure of making the alleged test. The "optometrists" even go the oculists one point better they claim to have a "dynamic" skiascopy which enables them to "find the errors of refraction without asking patients any questions," and while they use their accommodation any old way. The funny part of it all is that many oculists have been deceived by the proposition and accept it as 206 A SYSTEM OF MATURE MEDICINE true, proving again their utter ignorance of the simplest principles of physiology. Oculist professors in the old medical schools have given testi- monials to the manufacturers of retinoscopes as accurate means of finding the exact correction. A Philadelphia professor, whose books "have been trans- lated into Chinese," according to his own boast, has the following to say about the value of the method, all of the quoted paragraphs are on one page of his latest book : ''The wonderful advantage of retinoscopy over other methods needs no argument to uphold it; the rapidly increasing number of retinoscopists testify to its merits." "With an eye otherwise normal except for its refractive error, and being under the influence of a reliable cycloplegic, there is no more accurate ob- jective method of obtaining its exact correction than by retinoscopy." "The exact refraction is obtained without questioning the patient." "Its great value can never be overestimated in cases of nystagmus, young children, amblyopia, aphakia, illiterates and the feeble-minded." "From what has just been stated, it must not be understood that the patient's glasses are ordered immediately from the findings obtained by retinoscopy, for, on the contrary, all retinoscopic work, like ophthalmometry in general, should, when possible, be confirmed at the trial case." Rather inconsistent is he not? First it is exact. Finally it needs con- firmation at the trial case. He says it is great for nystagmus, children, etc. Nystagmus is an oscillation of the eyeball and he would have no more chance with such a case than the Dutchman had to catch his famous flea. Children and feeble-minded people will stare straight into the mirror despite the efforts of all the -doctors in the world, when nothing can be seen; beside that they would accommodate just the same as sane grown people, no mat- ter how much dope was put into their eyes. While this oculist knocks the dynamic skiascopist by insisting on atropinization, he makes himself ridicu- lous by contradicting his first assertion of exactness and by calling the test valuable for feeble-minded, etc. He couldn't fit anyone of any age or frame of mind with a mirror. Nor can anyone else, for reasons which will be shown very shortly. "Instruments of precision" is a favorite expression of oculist and "op- tometrist." It sounds mysterious "don't you know." We even read in "optometrical" literature of the "value of the sphygmomanometer to the "optometrist." Verily the love of mystery is second only to ego in man- kind generally. The situation makes it necessary that all of this matter be handled with- out gloves or mincing of words. The public pays too dearly for its foolish- ness in licensing classes of people to practice professions and alleged pro- fessions with immunity from liability for the damage they do and liberty to persecute honest men and women who are of superior qualifications but who are not in favor with the powers that be. Few readers may believe it, but it is a fact, nevertheless, that the alleged "laws" for the "protection of the public" are purely political, secured with exactly the opposite design by those who spend time and money to get them through the legislatures. The people who father them and the law-makers who pass them are "crooks" OBJECTIVE AND SUBJECTIVE EYE TESTING 207 if ever there were any such characters. Take the "Pure Food and Drug" law, passed by Congress, for an example : One of the big promoters was Dr. Charles Page, member of the Medical Trust, Boston, Mass. He sent out a circular letter to all, or nearly all of the doctors in the United States urging them to push their representatives in Congress to pass the bill, promising them that if the job could be done it would put patent medicine manu- facturers out of business to the tune of $165,000,000 annually, which neat sum would then be the plum to be divided among the doctors, who pre- scribe the same old stuff. Was not that patriotic? I have no use for patent medicines. I have no use for prescription medicines. If compelled to take one or the other I would take the patents, because they are made to be harmless, while the average doctor, protected by his license is too much in the habit of giving lethal doses. If the public is foolish enough to take either, I recommend the patent. Which is the worst for the victim : to take a medicine manufactured by a physician and sold in car lots to department stores, where it sells at 69 cents a quart, or to take another, made by non-medical men and sold to physicians and drug- gists in liquid, tablet, pill and powder forms, at tremendous profits, to be peddled out to the public for other profits? Prescriptions have caused more people to form opium and cocaine habits during the past ten years than have all of the patents ever sold. It is reported by Medical Trust journals that about one-third of their own members are dope fiends of one sort or another. Are they fit to be licensed and trusted with the lives of citizens and their children? But worse than the devilish dope they give in competition with the patent medicines, is the stuff they want to shoot into people with hypo- dermic syringes. A youth leaves his country or town home and comes to the city to a medical college. The first thing he does is to get into a "frat" house to have a good time. If he was set to work at his studies as we do in our school he would have no time for carousals ; but, the number of doctors is too great and it must be kept down by keeping the rising generation in school four to seven years, while his father and grandfather finished the same work and did it better in two years. After he has spent four years in one of the old schools of medicine he comes out absolutely unfit for any- thing, because his ego and prejudice have so deranged his brain cells they inspire him to join the A. M. A. (Medical Trust), part his whiskers in the middle, or trim them to a point, look wise, carry his medicine ca-se a la mode and starve to death "ethically," or, at most, average $700 a year. They catch the infection early too. Occasionally a party of "freshies," from one of the "orthodox" schools in Chicago, drop into our offices and pro- pose to "look us over" and to ask us to "explain our work" to them in a few minutes. I ask them how long since they were weaned. The kids have natural talents, probably, but after they have been in an orthodox school a year their highest ambition is to go down "Peacock Alley" at the Congress hotel and hold a riot; which idea their professors encourage with bail bonds to keep them out of jail. Fathers, do you want your boys edu- cated that way? If you do don't send them to us. We do not stand for such nonsense two minutes. 208 A SYSTEM OF MATURE MEDICINE Hero-worship and a craven desire to imitate somebody constitute a, baneful duality. The church, on the social side, and the self-styled "regular" medical sect, on the professional side, have had their day. Nature is too big for both and is surely coming into the ascendancy in the very near future. Progress is hampered by the foolish imitators of the older sects, but they are so damned foolish they make the whole scene ridiculous enough to make the dullest see through the grand farce. It was not medical science nor Christian science that conquered yellow fever in Havana, in Rio de Janeiro and other Southern cities. It was drainage. It was not mosquitoes that caused the fever. It was swamps, sewage, in- sanitation, that cause both mosquitoes and noxious gases, the last of which set up acute malaria with malignant toxaemia which killed thousands, while yet other tens of thousands were killed by fear. "The Spirit of the Plague entered the city gates. "One, watching, asked : 'How many wilt thou slay?' " 'A thousand' quoth the Spirit, and passed on. "The Plague had ceased ; the Spirit passed the gate. "The watcher cried ; 'Ten thousand didst thou slay !' " 'Nay ; one.' the Spirit said ; 'Fear killed the rest.' " The rite of vaccination has produced dozens of new diseases ; antitoxin has killed thousands by causing tetanus. The people know it ; yet when one raises his voice in protest, some newspaper doctor will assert that "anyone who disputes the efficacy of vaccination needs an inquiry into his sanity." This bluff works oftener than it fails; and if it does not, the scamps figure that they have the advantage in publicity and in compulsory "laws." Look at the death notices of "regular" doctors : Pneumonia, cerebral hemorrhages, heart disease, cancer, erysipelas and suicide are the principal causes given in the Journal of the American Medical Association every week. Dozens of them under fifty years of age. They can't even take care of them- selves. They are not good as general practitioners ; they are bluffers and empirics in specialties. Now, to return to the thread of our narrative in the so-called specialty, Ophthalmology. With us it is not a specialty ; but is a system of general practice, limited, it is true, to a certain extent, yet it is more practical and useful in a general way than any of the "systems" in vogue from time to time. It is not a new system. It is as old as creation. We have been teaching it for twenty-three years and practicing as well as studying. What we have to say here is all demonstrable clinically. It will be seen that it could not be done with a retinoscope, or any- other machine : Our patients are all awake and exhibiting all sorts of symptoms, from inflamed lids to cyclitis ; from clonic spasm to cross-eyes ; from simple head- ache to chronic dyspepsia ; from the amenorrhoea of young girls to the hys- teria of elderly women ; and a hundred more alleged "diseases" which are due primarily to nerve strain in the efforts to overcome hyperopia. Our Ophthalmologists have to know how to find the contributing causes and re- move them in order to get the desired results from the glasses. To do all this they have to know general anatomy and physiology differently and bet- ter than the old school general practitioners know those subjects. That is why our Department of Ophthalmology is not simply a leader of optical OBJECTIVE AND SUBJECTIVE EYE TESTING 209 schools but is a leader among general schools of practice. Our entire Neu- rological course, including Ophthalmology, of course, is in a class all alone, and if others continue to stick to their fanatical notions about long terms of attendance and their crazy-quilt methods of instruction, with their students stuffing themselves with false notions of importance, Greek letter societies, etc., we will always occupy the entire field. The reader will see already that if we do all we have claimed in the last paragraph above, the retinoscope, or any other instrument, would not cut much of a figure. Our work embraces the duality objective and subjective tests. We do not want any machine that will do the work without our ask- ing patients questions. We want to use our brains and we want our patients to use theirs. Our subjective tests are not such as the "optometrist" and oculist employ. We do not hold lenses in front of the eyes and ask patients "do you see better with this," as the others say they do in such tests. We have test cards and we know what they mean. We know the value of the distance represented by each line of letters ; and we know how to measure those letters to find if they are of correct size. We require patients to read the letters aloud. We do not permit them to commit the letters to memory. If any give us such symptoms we require them to read the lines backwards. Our testimony as to what the acuteness of vision of any of our patients is would be accepted as first hand information in any court in the world. Yet the "optometrist" calls it second-hand information. The manner in which he gets it is second-hand ; but because he does work that way is no sign that subjective testing by others is incorrect. The oculist and "optometrist" talk about Fogging as if they knew how to do it. As I originated the Fogging System, and the others admitted it long years ago by calling me "Old Man Fog," my rights are established. I am ready now to tell them they know nothing about Fogging. If they will read this carefully they may get some ideas about it ; after which I have something else in reserve for them : First, merely putting on strong -\- lenses and reducing them with - or by changing the + f r weaker ones from time to time, until the patient sees as well with lenses as with the naked eyes, is not fogging. Second, putting on strong -f- lenses and weakening them until vision is as good as possible ; then increasing them gradually by the changes until the strongest the patient will accept and see well is found, is not fogging. Third, putting on strong -(- lenses and after weakening them by several changes in which, with one lens in each hand, one a little stronger than the other, the second one always gives the best vision, so that the patient has come to expect it, the coming back with the same lenses and asking him to read another line, which he often does, sometimes suffering himself to be deceived into relaxing accommodation so that he comes from 20/80 to 20/20 without further weakening of the original lens, is not fogging. Some who have seen me do this called it a miracle ; but when they learned better they knew that was not fogging; and they knew that our imitators have never been able to do this little trick. Fourth, having a system of procedure which tests the elasticity of the tissues and the nerve status, the quality and quantity of nerve supply, the 210 A SYSTEM OF MATURE MEDICINE disposition and temperament of our patients, so that we can prescribe Tem- porary lenses, together with such other instructions, which, if followed, will permit Nature to get the general systemic conditions in form for us to complete our work, is not yet fogging. Hence the joke is on our imitators, who have written much about fog- ging when they knew nothing whatever about it. Fogging, my lads and lassies, is what we have been doing to you all in general, and to those who came to us as students, in particular, for twenty- three years. We have also been fogging the public. Fogging, my dears, is Educating people. We have kept the oculist, "optometrist" and optician guessing as to what we were going to do next. Alleged competing schools have addressed correspondents, telling them they taught what we do. Re- sult, many of the recipients of such letters came to us to get the subject at first hands. The optical journals and medical journals vented their spleen in a manner that showed their readers we must be some pumpkins. "Opto- metrical" and medical speakers and writers criticized our conduct in shatter- ing their old idols and even attempted to smother us with ridicule. Oh, we had 'em Fogged "to a frazzle." We had our own papers and books with which to answer them, too, and we have circulated those papers by the hundreds of thousands, Free, to the General Public. We had no advertising space to sell. We had no "Kryptogram" or "Keytole" or "Medicated" lenses to sell. We had no "Dynamic-skiasco-meters" to dispose of to suckers. W r e simply paid the printer and wrote the truth as we saw it and could prove it. We impressed some studious, ambitious minds that we were not in this work for mere dollars. We impressed them that we knew what we were talking and writing about. Many who had attended the alleged optical schools, and the old schools of medicine, came to us and took our work. They got the evi- dence at first hands and they got the proofs so they know how to use them. As another result scarcely a day passes that we do not receive letters from all directions saying: "I have seen- the work of your graduates and it is something marvelous. Have you any representatives in our vicinity?" Ah, that's Fogging, children, and "He who laughs last, laughs best." I will not rub it into my gentle adversaries of the past any harder. Now, as the prestidigitateur says, "Watch my hand and I'll show you just how I do it." The following is the Fogging System: When a patient comes into my office it is a pleasant place, neatly but not gaudily furnished ; a polite lady is in charge and knows who have ap- pointments so there is no delay. If it is a new case, she arranges for an examination, gives necessary information and collects the examination fee. She uses her discretion in questioning prospective patients and saves much time by her reports to me. When the patient gets into my private office he, or she, is made as comfortable as possible, facing the window, while I have my back to it so I can study expressions of countenance, complexion, proportions of development, general physiognomy, disposition and tempera- ment. I invite confidence and become a good listener, while the "tale of woe" is recited ; after which I hold court and cross-question the witness ; finding, many times, that some statements have been too strong and some not strong enough ; all of which is duly recorded as we proceed. Next, I OBJECTIVE AND SUBJECTIVE EYE TESTING 211 have a distinct understanding that all of our dealings are confidential : that I do not discuss my cases with other doctors and I do not permit my patients to consult other doctors or listen to other people's comments about the case so long as it is in my charge. This saves a lot of annoyance from meddlesome Matties. Next, I show that there are many, or few, contribut- ing causes to the conditions exhibited, and that it will be useless, or prac- tically so, to take the case unless I am to be permitted to cover all of the causes, thus insuring good results to the patient and protecting the reputa- tion of Neurology. Next, I use the ophthalmoscope to ascertain the quality and quantity of blood in the general system, the number and size of the vessels, the relative number of veins and arteries, and if there are any local visible pathological signs or anatomical freaks, I find them. I use the direct method always; then I see the real things right side up. My mys- tery-loving brothers argue for the indirect method, because they have not yet been Fogged enough. Incidentally I get close enough to the patient to note the body odors, if any exist and I know what they mean also the odors from the nasal passages and the mouth ; I know how to distinguish between catarrh, bad teeth, whisky, tobacco, cigarettes, chewing gum and a sweet, healthy breath. Next, I listen to the heart and lung action I wouldn't give a damn a dozen for stethoscopes and sphygmomanometers ; I keep my ears clean and in working order ; I can stick a stethoscope against a brick wall and hear rales and murmurs. I know what good heart and lung action is ; hence I know what bad action is. I also know that a lot of the so-called bad action according to accepted "authorities" is nothing more than the simple product of eye strain. I have had many a case of "mitral valve disease" and "tobacco heart" that proved to be nothing more than a natural result of excessive nerve demand for the eyes. I have also often found such patients wearing -- lenses of considerable power when they needed -f- lenses of greater power, hence they were in a worse condition with their lenses on than without. I have found them wearing compound lenses for near work only when anyone with brains enough to drive geese to water should know that anyone, under about forty-five years of age, who needs glasses for near work needs them for constant wear, and that anyone who has astigmatism should wear glasses constantly. Next, I take the acuteness of vision of each eye separately and make a record of it for reference 'during the test and for future use. If my patient reads the 20 line at 20 feet I know vision is normal ; but I do not know the eye is normal ; I know it is not myopic ; but it may be very hyperopic. If only 20/30 or worse is re- corded, it may be myopia, or hyperopia without accommodative power sufficient to overcome it ; it may be myopic astigmatism, hyperopic astigma- tism, mixed astigmatism, retinal atrophy or hypertrophy. If it is 20/15 or better I know it means at least 1.00 D. hyperopia and possibly as much as 2.50 ; and I know there is no astigmatism worth looking for, because I know that a whole diopter of error in an eye only changes the principal focal point about a quarter of a millimeter, hence a quarter of a diopter of astigmatism would only change the focal distance in one meridian a quarter of a quarter of a millimeter, or 1/16 mm., hence would not impair vision. I know the chaps who talk and write about correcting one-eighth 212 A SYSTEM OF MATURE MEDICINE diopters error need more fogging. Next, I make a dynamic test of the nerve supply ; some call it testing the accommodation, but they have no tables or other records to go by and the test is not worth anything. The Neurometer is based on this and other tests. I know exactly how much my patient should show to be normal; I know about how much is going to be shown; but I make no guesses ; I make the test and record it. Then comes the static test, which is an involuntary nerve test ; it is a check on the dynamic one and if it disputes that test I believe it most until the other is supported in the final analysis. This test is made with a double prism so placed in front of the left eye that two lights are seen where there is only one at the usual testing distance of 15 or 20 feet, and they must be in a perfectly vertical position ; I place on the right eye a dark disk and behind it a colored glass, usually red, but any color will do, as I must be able to know for sure which eye is seeing the light that should be in line with and midway between the other two.. If the red light is seen out of position, on the right, it indicates a weak nerve supply generally and it is exhibiting through the third nerves by way of the internal recti muscles ; if it is out of position, on the left, it indicates nerv- ous irritation to the point of tonic spasm, and the exhibit is by way of the same nerves and muscles as before ; if it is out of position, above or below the mid-point, but in line with the white lights, it is an indication of an irregular distribution, exhibiting by way of the superior and inferior branches of the third nerves to the superior and inferior rectus muscles; if it is out of position obliquely on the left, it is an erratic distribution with a tonic spasm ; if out of position obliquely to the right it is erratic dis- tribution with a tendency to weakness, and we record the exhibit for use in the final tests and in analyzing the case by the Neurometer. All of the symptoms exhibited in these several tests are preliminaries which could not be found in any other manner. No instrument or machine would even approximate them. Without them no one could proceed with a search for the amount of the refractive error with any hope of certainty. Some of them are objective and some are subjective. To be able to make these tests without ( knowing their full significance would not avail the practitioner a particle. They are not available to us until after we have made the refraction test and have repeated the three last tests, mentioned in the preceding paragraph, with the correction found before the eyes. Then we make our calculations as described in the chapter on the Neurometer, making certain additions for physiological demands and certain other ad- ditions for temperament, then certain discounts for symptoms, when the final figures tell us whether we have something near the correction of the error, and also tell us exactly the condition of the patient. In seventy-five per cent, of all cases we find it necessary to order temporary lenses which stop the nerve strain through the eyes while we attend to the contributing causes of the entire situation. This is what makes our Ophthalmology a system of general practice, while the alleged systems employed by all others are "merely fitting glasses," under conditions which render it an impos- sibility to find anything approaching the real amount of the error ; and if they could find the full amount and prescribed it, patients would not get more than partial results because the contributing causes have been ignored. OBJECTIVE AND SUBJECTIVE EYE TESTING 213 "Dynamic skiascopy" would be a joke were it not that its advocates take themselves seriously and the public are the victims of misguided practices. In other chapters it has been explained that the eyes in their static condition, that is with their accommodative apparatus at rest, exhibit the minimum -f- power; that the nervous system is so sensitive that the pupils close automatically the instant the light becomes uncomfortable ; that the nerves which operate the iris also operate the accommodation; that continued ac- commodative efforts are always accompanied by reduction in size of the pupils ; that any test which may involve the accommodation as an antagonist is a subjective test. In the last point mentioned we have the reason retino- scopy is not an objective test. As shown in Chapter XII the theory of retinoscopy, as a physical proposition, is all right. But we stated there that physiologically it is a colossal humbug. Here are the proofs : An emmetrope, looking at a point 20 feet away would have to accom- modate one-sixth of a diopter to see clearly; hence, an operator working at one meter would find the reversal point with + .83%. The "experts" always claim they find it with -f- 1.00, showing they do not even know the theory of their business. As a matter of actual fact, they often find lenses necessary to reverse the shadow, as we have found many of their victims wearing lenses when they needed strong +. A hyperope looking at 20 feet would accommodate the amount of his hyperopia and one-sixth of a diopter more, making him present exactly the same proposition to the observer as the emmetrope did ; even if the hyperope relaxed his accommoda- tion in order to see at the distance with the -f- lenses he would not be nearly so liable to relax it while a fierce light is being thrown into it as if there was no distributing factor present. A myope cannot see at 20 feet until - lenses are put on, and when that is done there will be accommodation for the same reason there was in hyperopia, namely, the excess light ; hence more - - would be demanded and we find, invariably, myopes are sadly overcorrected, which makes them hyperopes, and hyperopes are sadly un- dercorrected, even to being given lenses, which increases their hyperopia. A Chicago retino-medico-optometrist, who is regarded as a great teacher by the unsophisticated, all over the country, advises full corrections in myopia and under-corrections for hyperopes. He has also "seen" latent myopia; he told me so himself. His fund of misinformation is only equalled by an- other Chicago "optometrist" who says he has a "method of fitting hyperopia and myopia with the ophthalmometer," known only to himself, and by a California "optometrist" who knows we are all wrong when we say the images on the retinae are inverted and reversed. To anyone who has the slightest knowledge of the nervous system and of physical and physiological optics and ophthalmology, the "dynamic skias- copy" story is too ridiculous for further mention ; but, as nearly everyone engaged in the practice of "optometry" and oculistry, know so little of the fundamentals that they are mislead by those who have the nerve to make a pretense of knowing, a little more space will be devoted to the dymanics : A patient who is not most thoroughly under the influence of a cycloplegic, (and it is dangerous to life to attempt to put one in that condition, as all oc- ulists who argue for "reliable" cycloplegics are compelled to admit), will 214 A SYSTEM OF MATURE MEDICINE use his accommodation, under any test, as naturally as he will use his lungs ; therefore any test of the dioptric system stimulates accommodative effort, no matter how mild it may be ; and, of course, any test with which the patient is entirely unfamiliar, such as throwing a beam of light into the eye, will be especially aggravating. It invariably brings on a tonic or clonic spasm and deceives the operator every time. The pretense of some that they have a way of having the patient fix on different points while they make the test from different distances and thus corroborate one test with another is pure "bunk," too silly to be considered, because if they could fit a case at one distance they could do it at another, hence would not need to experi- ment. Some of those fellows who have been taunted by their friends with my invitation to come to my office and fit me and one other with glasses, correctly, and receive therefor the sum of $500, have replied : "Who is going to decide when the job is done correctly?" and the bluff appears to have worked, from all I can hear. Now, let it be understood that any person who thinks he knows how to prove his work, as those selfsame fellows say they do, when they are talking to the public, or to "optometrist" suckers, should bring that knowledge with him and come after me. They do not appear to realize how illogical they are. By our system we prove our work absolutely before we discharge a patient. It appears they know so little that they do not imagine it is possible to prove anything. I fear they are so ignorant I could not show them the simple laws which prove they are mistaken, unless I could have them with me several weeks and first teach them the optical alphabet. One set of chaps who came after the money once, declared in the presence of witnesses that if a person can see as well through a + -50 lens as through a + 2.00 it proves it is as good a correction. The man who made that declaration is today a licentiate in Illinois by "ex- emption." Optical houses who advertise retinoscopes, ophthalmometers, ametropo- meters, etc., as "instruments of precision" know they are liars when they do it just as they are liars when they tell our prospective students that we work people to death in our school. They dare not say we haven't a good school ; but they do not like us because we do not encourage our students to load themselves down with debts and such instruments. We do recommend that each student possess and use an ophthalmoscope ; one cost- ing $4 is as good as is made and is never out of order when wanted, as the "luminous" ones often are. We recommend a good trial set ; the one I devised many years ago is most convenient ; and there is not a "sott-markee" in it for us whether they buy that style or not. We tell our students that a comfortable operating chair is worth a wagon load of instruments ; that for purposes of study and profit in information, a clinical thermometer is a con- venience, as are also a urinometer and a stethoscope; but they are not absolute necessities, as are the ophthalmoscope and test lenses. An office scale for taking weights and measuring heights of patients and a smaller scale for weighing foods are great conveniences. There are no "instruments of precision" except those with purely physical functions, and few of such are absolute. Our method of pro- cedure with the eyes is much the same as our method of making general OBJECTIVE AND SUBJECTIVE EYE TESTING 215 examinations ; it is systematic and we only arrive at final conclusions after we have had the case in charge until its physiological capacity for adjust- ments has adapted itself to the new situations and the symptoms of disorders have disappeared entirely. Then and not before, we have the proofs that our work is correct. We endeavor, during eye tests to induce the accom- modative power to reverse its engines, that is, to relax and reveal the full error ; but it occurs only when the patient is of such an age that presbyopic tendencies enable us to settle the matter, and even then we often insist upon second and third visits. We do not employ cycloplegics because : First, they are both dangerous and unreliable ; second, even when they take partial effect they interfere with our repeating tests after we have finished our refraction test ; third, many people object to them not only because of the discomforts they produce, but they know those who use them do it for ad- vertising purposes at their patients' expense; fourth, we have a method that is decidedly satisfactory to ourselves and our patients. The machines used for testing the refractive qualities of eyes are all makeshifts and the subjective ones are dynamic, two faults which render them unreliable. They are expensive and using them consumes valuable time which can be utilized to advantage in proceeding by our method. Many of them were devised by authors for the purpose of impressing their colleagues and the public with their alleged knowledge of the subject. The others are made by manufacturers to sell at enormous profits. If any doctor wants to try one all he need do is to advertise for a second-hand one and he will be flooded with replies from those who have learned by ex- perience the truth of my statement. The prisoptometer was one of the first ones. It is made with a revolving double prism and a target four inches in diameter, to be placed at a speci- fied distance and the patient is to tell the operator when the two targets, seen through the prisms, are touching, lapping, or separated. The first is said to indicate emmetropia, the second myopia and the third hyperopia. If there is astigmatism the targets may touch at one position and lap or separate at another, as the prisms are revolved ; or they may lap or separate at one position and lap more or separate more at another ; or they may lap at one position and separate at another, indicating respectively, simple, com- pound, and mixed astigmatism. The bad feature of the machine is that it is the most "subjective" of all known "instruments," because the operator is compelled to let the patient decide the matter without previous experi- ence ; and, as a matter of fact, no operator could ever become sufficiently expert to measure his own errors, for the simple reason that none can tell when the two targets are just touching. The retina-ophthalmoscope which has been so vigorously advertised dur- ing the past eighteen years, was first made from a pattern constructed from ordinary mailing tubes by the writer, who, by that means, satisfied himself of the impossibility of machines ever being practical. The contrivance was thrown into a closet and lay for months, when one day the head of the optical house exploiting them came to visit me and suggested that I get up a machine and they would make it. I produced the apparatus and gave it to him with the injunction that I would not care to have my name attached to 216 A SYSTEM OF MATURE MEDICINE it. So it was named for a noisy oculist who was prominent at that time and a great many of them were sold. As I could not endorse it and was placed in a position where I had to denounce it, by the claims of retinoscope fiends, the friendship and business relations of my school and the firm were broken. All other subjective machines, whether for testing the refraction or other eye exhibits, are of no practical value to the operator who understands his business. When the argument is offered that "it is a good thing with which to get a quick idea of the nature of the condition" it tells at once that the speaker or writer hasn't the faintest idea of practicing according to a system. No rational, educated Ophthalmologist cares whether it is hyperopia or myopia he is going to deal with ; he regards it as a waste of time to powwow around a patient with mirrors, machines or lassoes. He has all the facilities he needs in his trial set, his ophthalmoscope and his training. The objective machines are represented in the various ophthalmometers, or keratoscopes. There are several of them, all constructed on the same principles, of course. One of their weaknesses is that the radius of the curve of the surface on which the mires are placed is fixed and the radii of eyes to be tested are not; another is the difficulty patients have in holding the eyes in position, in proof of which statement one has only to test an eye several times in succession; another is it is a monocular instrument; another is that while the principal meridians of an astigmatic eye may be found, the amount of the error is very indefinite, and even the meridians located may be oblique during the test, but when the correction of the eyes is completed they will be found vertical and horizontal. CHAPTER XXV. Situation in Emmetropia, Hyperopia and Myopia, with Lens Removed. Aphakia means absence of the crystalline lens. It presents some inter- esting conditions for calculation : We found, page 95, that the power of the crystalline lens, in its posi- tion, in Emmetropia, is 19.737 diopters of the total 63.00 diopters com- prised in the entire system. Removing the lens from such an eye leaves the center of curvature of the cornea as the optical center and all nodal points. The radius, divided by the excess index, gives F' and adding the radius to F' gives F 2 ; hence : R, 7.84-f- .3365 = 23.298% F',+R, 7.84 = 31.138% F 2 . A ray starting from the posterior pole, 22.86 from the cornea, divergent from the axis would still be divergent after refraction by the cornea, be- cause the distance, 22.86, multiplied by the opposite principal focal distance, 23.298%, and the product divided by the difference between 22.86 and the near principal focal distance, 31.138%, gives a negative focal distance of 64.3349, thus: 22.86X23.298% = 532.60752 22.86-31.138%= 8.278% Placing a correcting lens 5.6651 mm. from the cornea and adding that amount to the distance found, gives 70 mm. or 14.25 D. as the lens required. It might be believed that if the eye had been hyperopic or myopic 1.00 diopter the above figure would require 1.00 more or less; but that is not so. Suppose the refracting system to have been normal before removal of the lens, but the eye was flattened posteriorly enough to cause 1.00 D. hyperopia. That means the combined dioptric power of cornea and lens would have to be 64.00 D. or 15.625 from optical center to put focus on the retina. Adding the distance from optical center to the cornea, 6.988, gives 22.613 mm. as the antero-posterior length of the eye; and, proceeding as be- fore: 22.613X23.298% = 526.852749 - 22.613-^31.138%= 8.525% = 63 ' 3619 negative F. Adding the same distance from cornea to lens as before, we have : 63.3619+5.6651 = 69.027 mm. or 14.48 D. lens required. Now suppose the cornea is deficient 1.00 D. but the antero-posterior length of the eye is normal, 22.86. That means a 62.00 D. eye, with a focal distance of 16.129 from the optical center. Adding the distance from optical 218 A SYSTEM OF MATURE MEDICINE center to cornea, 6.988, gives 23.117 as the distance from the cornea to the principal focal point, with the retina .257 mm. in front of it, or 22.86 from the cornea. The deficiency being in the cornea, the first principal focal distance of which is, normally, 23.298% or 42.93 D., to find the radius necessary for the calculation: Deduct 1.00 D. from 'the normal, leaving 41.93 D. with a first principal focal distance of 23.849 mm. This, multiplied by the excess index, .3365, will give the radius : F', 23.849X.3365 = 8.025 = R, and F' 23.849+R, 8.025 = 31.874= F 2 The distance from the retina to the cornea is 22.86, and, as the lens is out, we are dealing with a single curved surface again : 22.86 X23.84<9 545.18814 . , , ,. , A ... . ,. . j_ r-rrr- = 60.482 negative focal distance. Adding the distance or if the fits do not exhibit until maturity, the situation is harder to handle. Practically all of these cases are Neurological ones, but as Ophthalmology involves much of the mechanical part of Neurology, no harm can come from what Ophthalmologists do, and they may save parents a large part of the expense in treating children, who, as a rule, yield more readily than older patients. Habits. These range from the talk habit to the cocaine habit, and cover a multitude of mental and physiological misdemeanors. We regret to say tHat the chief causes are : First, general ignorance, even among so-called educated people. Second, the practice of drug doctors who give medicines which develop drug habits insidiously. Third, a general indifference to GENERAL DISORDERS CM LED "DISEASES" 237 the study of those things, to do which and secure permanent health would require the practice of a reasonable amount of self-denial. Fourth, and last but not least, uncorrected hyperopia, which is the primary cause of 85 per cent, of all human ills, by reason of the fact that it institutes an extraordinary nervous demand for accommodation, which first irritates and then weakens. Among the symptoms of irritation are uncontrolled desires for something, the individual does not know what, but he automatically turns to stimulants, liquor, tobacco, drugs, social excitement, religion, politics, adventure, even to committing crime. It is the province of Neurology to call attention to these things in language that even children can understand, and we teach our students to advertise in what we regard as a legitimate manner, not vaunting themselves, but by giving people information. This naturally introduces them to the public, and if any readers find they have conditions which they are unable to control, they naturally consult one in whom they have con- fidence. In writing these circulars of information, our doctors educate them- selves, as well as the public, just as we educate ourselves in teaching our students. Heart Disease. See Angina Pectoris. In this connection it is proper that the reader should have some information. The heart is a big muscle, comprising four compartments, the two upper ones are called auricles and the lower ones ventricles. Into the right auricle flows the blood from all over the body, through the superior and inferior venae cavse. From there it passes through the tricuspid (three-leaf) valve into the right ventricle; then it passes through a series of semi-lunar (half-moon) valves into the pulmonary artery, which distributes it throughout the lungs, where carbon- dioxide is discharged and oxygen taken on ; next it is delivered by way of the pulmonary veins, as arterial blood, into the left auricle, from which it passes into the left ventricle through the bicuspid (two-leaf) or mitral- valve ; thence by way of a series of semi-lunar valves into the aorta, which passes up over the left lung and down behind it, giving off branches as it goes and finally after passing through the diaphragm close to the spinal column, it bifurcates into the two common iliac arteries, and each of these fork again into the internal and external iliacs, the first supplying the abdominal viscera, and the second going largely to the legs. The heart oper- ates by two motions, systole and diastole. It is a sort of combined pumping and syphoning process, the contraction being first at one end and then at the other. When the dilation is at the lower end, the contraction is above, thus the ventricles fill ; then as the contraction below takes place, it pumps the blood to the lungs and to the aorta, while the dilation of the auricles causes suction, which draws the blood from the venous system and from the lungs. This action alternates like the beats of a clock, and should be as regular, running 70 to the minute in adults, normally. When it runs too fiast or too slow, or misses beats, it is not the fault of the heart, but of ir- ritation or weakness of the nervous system. If the valves leak, it is not "valvular disease," but is simply due to enervation, which is deficient in- nervation. Our Ophthalmologists have corrected more of this trouble than all the old school doctors ever will. When the old schools win a case, it is purely accidental. 238 A SYSTEM OF MATURE MEDICINE Headache is also called migraine. Sometimes this exhibits merely a dull, continuous ache. Sometimes it takes the shooting-pain form and is called neuralgia. The very fact that the old schools have given coal tar products, morphine and other drugs to suspend the sensation of feeling, and called it a headache "cure" is sufficient proof of incompetence to warrant the passage of laws forbiding the employment of drugs. From the Harri- son anti-narcotic law much benefit has resulted, and more will result, be- cause when people wake up to the fact that cocaine and morphine users are not the only victims of the drug habit, but that women and children by the thousand are being doped for headaches, that will be stopped, and the causes of the aches and pains will be remedied. The doctors will have to learn Neurology, or go out of business, whether they learn it from us, or from our books, or from the sheer force of necessity, because they will not be allowed to maltreat patients any more. It has to come. Pain and fever are Nature's two most conspicuous beneficent provisions against dis- order, because they automatically warn us when anything goes wrong. It is a shame that the old schools of medicine, instead of teaching how to utilize these things to locate causes and remove them, have taught the use of the hypodermic syringe and internal medication to suppress those exhibits. When a burglar proposes to rob a bank, he cuts the telephone wires runing from the bank to the detective agency. We never hear of the fire department cutting its own wires, or of the detective department cutting wires. It is only "scientific medical" men who commit such foolishness. Hypochondria is a state of melancholy into which certain classes of cases fall from long continued disorder, and while, as a rule, these are all Neurological cases, the Opthalmologist may do an enormous amount of good by correcting the hyperopia, and giving instructions how to take baths and exercises. Of course, in considering hyperopia as a cause of nervous disturbances, it must always be remembered that the greater the amount of hyperopia, the greater its potency as an exhaustive feature, and the less the amount of hyperopia, the less potency there is ; but when we remember that one unit of hyperopia causes 23 per cent, increase in the daily nerve demand, and every additional unit adds 23 more per cent., its potency as a trouble causer may be appreciated. Hysteria is the opposite condition to the one named above, and this class of cases, while making much more ado than the other, is many times easier to handle, so far as physiological control is concerned. Occasionally, when the melancholy ones have not lost their mentalities to a large extent, so that they have no ambition to get well, they are easiest to handle. The hysteric must be handled gently but very firmly, and, as a rule, when they are impressed with the fact that our analysis is not a diagnosis; that there is no guess-work or opinion by us; that it is a message direct from Nature through their own nervous systems, interpreted by us after being care- fully trained for it; that it is law which must be obeyed; that in order to insure Nature will not be tricked we require them to pay a good fee in ad- vance as a guarantee they will obey the law, we win all the time. Insomnia, sleeplessness, is one of the frequent symptoms of nervous irritation caused by excess demands, and it is often accompanied by a resort GENERAL DISORDERS CALLED "DISEASES" 239 to coffee, tea, liquor and other stimulants, for which we substitute lemon, pineapple, and other fruit juices, while readjusting the nervous system, after correcting the hyperopia ; we also direct the taking of hot baths just before retiring, or sometimes a walk in the cool night air, so that the re- action upon returning to a warm room induces sleep. Leucorrhoea is not what it has always been considered by the phy- sicians. It is simply a local exhibit in the vagina, produced in much the same manner that a coating of the tongue is produced ; and the coated tongue will always be found in such cases. It is. simply a stage of debility, and it may be present in several stages, that is, it may be the only symptom, or it may be present and there be also prolapsus uteri, a falling of the womb. The only treatment that can possibly do any good is to get the system built up nervously, and the process of doing that develops good blood, good bone, good muscle, and a good brain. Many of these cases are purely Ophthalmological, because they are associated with hyperopia, which is the chief causative factor. The patient can give herself the local treat- ments, which consist of baths and injections of strong, warm salt water, twice daily, after which rest should follow. One of the douches may.be taken at one or two o'clock, and the other at bedtime. Menorrhagia is another menstrual exhibit, meaning too much flow. There may be dysmenorrhea at the beginning, followed by excess flow, or the flow may be too frequent and too long-continued without pain. All such cases are dangerous, and if the Ophthalmological routine does not give marked results in a month, which it often does, the case should be sent to a Neurologist. Morning sickness is a very common exhibit by pregnant women, but it is often exhibited by other people, particularly girls, between 14 and 20, whose nervous conditions are below normal. Some of them have developed ovarian or abdominal tumors, and gossipy neighbors have caused their humiliation, even disgrace, by charging them with "immorality." If there is any such a thing as ''immorality," I would apply it most strenuously, and as the rankest exhibit, to those whose slanderous tongues are always ex- pressing opinions about matters which are none of their business, and of which they know nothing. According to their own estimate of the word, it fits them perfectly. Ophthalmologists can take nearly all of these cases, and by the usual correction and suggestions bring perfect relief quickly. Pneumonia. This is not caused by hyperopia, although a person whose system is already weakened by the strain from that error is less liable to resist the atmospheric and other conditions which produce pneumonia. The reports show that about 15 per cent, of the drug doctors who die, the causes of whose deaths are given, are taken by pneumonia. This is absolutely disgraceful. Anybody and everybody ought to know how to take care of pneumonia. Hence this paragraph : At the first indication of sore throat, or congestion of the lungs, the victim should get into, or be put into, a hot bath, and the heat increased until profuse sweating results, then dry quickly, and put to bed ; take a good sized bath towel, and soak it with cold, salt water, wring it out a little, and lay it on the chest and neck from the breasts to the head. The objects are, first, the heat relaxes the nervous 240 A SYSTEM OF MATURE MEDICINE tension, reduces the fever to practically normal in fifteen minutes, and dilates the caliber of the trunk-line blood vessels. Second, the cold ap- plication to the lungs causes a contraction of the vessels, stimulates the nerves locally, and relieves the lungs from congestion. If, after an hour or so the fever comes up again, and there is further congestion, we know the dose was not strong enough, so we give another one, and keep it up as often as is necessary to conquer. Usually three or four baths are sufficient; often one. No doctor is needed, but if one is called, he should at least have com- mon sense enough to know what to do. In the way of medication all we give to such cases is all the fruit juices they want to drink, lemon, orange, grape fruit, pineapple, mixed or separate, and patients should be kept in the house for several days until the system is restored to normal, and has had a rest. The system of practice which we call "Mature Medicine," and of which this volume is the mechanical section largely, is based upon mathematics, used in as simple forms as possible, and with all the common sense at our command. CHAPTER XXIX. Human Ills and Their Causes Viewed From a Rational Standpoint. All of the Ills of Humanity are due to Nerve Shock or Nerve Strain, taking the proposition as a fundamental one. The following diagrams are to aid students in comprehending- the Duality System of Analysis: Causes (Congenital Deficiency Chemical Debility Body Infection. . Idiopathic {Systemic Inoculation Internal Mechanical. . . . Organic External Sensory Ills . . (Emotional Motor Hysteria Real , Melancholy Accidental Shock Mental Strain (Education Benign 1 False Malignant I Environment (Mental , Positive Negative Shock ( Congenital Physical Strain Malnutrition {Voluntary. . Infection Habitual 1 Acquired Occupational T 1 Atmosoheric r Skeletal Accidental Fractures Anatomical.... [ Muscular Dislocations Cuts (Systemic Sprains Nervous Physiological. . Organic < Vascular Real Imaginary For many years I have asserted that there are ten Possible Causes of Human Ills, all of which are subdivisions of the Duality mentioned above. Of course there are innumerable possible combinations of these causes; but all involve the original Duality; hence my claim that all Ills are Nervous Ills, and my differentiation of our methods as Neurology, a System of Ma- ture Medicine. I would not be understood as making any claims to absolute perfection. This is impossible for two reasons : First, Nature, alone, is infallible. Second, a mature individual is always capable of adding to his store of information and it follows, naturally, that Systems of Practice may be Mature, yet be susceptible of Improvements. It is with the hope of 242 A SYSTEM OF MATURE MEDICINE stimulating investigation and aiding in the advancement of Natural Laws as the most promising study, that this book and the one to follow are pub- lished. The Ten Causes are: 1. Congenital, due to conditions pre-natal. 2. Infection, at the moment of birth or any time thereafter. 3. Malnutrition, from lack of food or from improper food. 4. Physical Shock, by accident or design. 5. Mental Shock, such as fright or appalling news. 6. Physiological Strain, as from hyperopia or over-eating, etc. 7. Mental Strain, as suspense, anguish, anger, etc. 8. Habits, drug, liquor, or dissipation of any kind. 9. Occupation, involving worry, hazard, etc. 10. Atmospheric Influences, exposure, climatic and otherwise. The following paragraphs refer particularly to the diagrams on the preceding page. There are sixty-three of them, one for each subject in the diagrams ; each is for the purpose of illustrating the application of the word as it appears in these arrangements, not necessarily the literal mean- ings of the words, nor what they might mean in other diagrams. It will even be noted that when the same words are used in different columns they have different significance : The ills of humanity have been due, in all ages, largely to ignorance. As far back as history goes, there is evidence that there were a few people who sought to educate their fellowmen, not only with reference to the hum- buggery of spiritual fads but also to those of all medical fads. Even the two factions, medical and religious, fought among themselves. The spiritual faddists who wrote the bible made frequent references in disparagement of the medical profession. In one place it says : "King Asa fell sick and called not upon God, but upon the Doctors ; and Asa slept with his fathers." A great many years ago an eminent student asserted : "Where you find a dozen doctors in company, eleven of them will be atheists." The average physician of today, old-school, is a member of some church organization, for business or social reasons ; many of them have so stated to me per- sonally. There is scarcely one of them who does not ridicule Christian Science and all other "faith cures ;" yet every one of them exhibits the most stupendous faith in the "curative" qualities of drugs. We Neurologists do not believe any of the nonsense about "cures," whether they be faith or drug. We know that after we have analyzed a case, and found it within range of recovery, if the patient follows our instructions, faith or no faith, there will be recovery. Hence we not only believe, but we believe because we know that the processes of Nature all tend toward good. The body includes a head, trunk and appendages. The head and trunk contain organs more or less developed, and this development is altogether dependent upon how the apparatus is cared for in the matters of supplying nutrition, seeing that waste is properly discharged, that there is sufficient exercise to promote development where it is most needed, and that excesses are not indulged in. To take care of this matter, each individual is provided with a Men- HUMAN ILLS AND THEIR CAUSES 243 tality, which is something we all know exists, although it has never been located in the process of dissection. In it we have evidence corroborative of a proposition we have often made, that a truth is anything which can be demonstrated physically or physiologically. We know anatomy is truth because we can demonstrate it physically. We know mentalities are a fact because they are demonstrated physiologically. The thing itself might be called by any other name, but it would still be true. Animals, for instance, have mentalities, not as highly developed as the human race, but there is no question about their capacity to think ; I have seen animals perpetrate jokes deliberately and laugh about it ; I have seen a live dog tackle an iron dog in a yard, and when I laughed at him, he actually blushed ; he was a white, tramp dog; we became warm friends and were on familiar terms for months. These mentalities are representatives of Infinity, residing with us during life. What Infinity is, we do not know, except as its laws are demonstrated to us physiologically by the movements of planets, the de- velopment of vegetable and animal life, and regular seasons, and the eventual evolution of all life back to its elemental state. The various theories de- veloped through imaginations of these mentalities are not provable either physiologically or physically, so long as they refer to the possibility of a. future life, reward, punishment, etc. This we know as well as we know anything, and we know that we or anyone else would be wasting time trying to effect a compromise with imaginary gods, or devils. We have evidence that such theories are very dangerous in the effects they exhibit through many mentalities. The insane asylums are full of religious fanatics who became dangerous to themselves and others. The morning this is written we have an account of a religious fanatic who murdered five people before he was killed by the police. It is a curious thing about these fanatical minds that they are apparently absolutely devoid of analytical capacity. For example, they write in the bible that the devil took Jesus Christ up on a hill and pointed out the beautiful landscape to him, offering it all if he would become a devil, and the readers point with pride to the reply of Jesus, who said, "Get thee behind me, Satan." Yet all through that bible we find bribe after bribe offered "to those who love me and keep my command- ments," and threat after threat to those who disobey. To a rational mind all bribes appear much alike. The devil did not do any threatening, and of the two propositions his is the best. He promised something tangible at once. The other is like life insurance one has to die before it falls due. Chemically the body comprises 14 elements in tangible quantities, some of them very small, and traces of a number of others. In an average body of 154 pounds, there are 3 pounds of nitrogen ; 111 of oxygen ; 14 of hydrogen ; 21 of carbon ; 2 of phosphorus ; 2 of calcium ; while of iron there is 100 grains ; fluorine 100 grains; silicon 2 grains; magnesium 12 grains; sodium 2 ounces, 116 g"ains ; potassium 290 grains ; chlorine 2 ounces, 47 grains ; sulphur 2 ounces, 110 grains. These are the constants. The inconstants are the same things in greater quantities, which are used up partly to replace tissue, and partly to perform the work of digestion. The old-schools teach the carbo- hydrate theory of diet. We teach the nitro-phosphate theory. Theirs has been a failure for generations. Ours has been a success for more than a 244 A SYSTEM OF MATURE MEDICINE generation. The reason is, ours is consistent with Nature, while theirs is purely artificial. As a matter of fact the~e is but one kind of chemistry, physically, and that is inorganic. The so-called organic chemistry, desig- nated as the chemistry of the carbon compounds, is a purely artificial classification, and is consistent with only one thing, which is the artificial idea of medication to "cure" disorders produced by deficient proportions of the body elements, instead of studying how to supply that deficiency naturally. The only true organic chemistry is physiological and it is en- tirely different from the physical. The mechanical body is sensory and motor, systemic and organic, in- ternal and external. Each division has its peculiar functions, some of which are voluntary, under control of the mind ; others are involuntary, unde*- con- trol of instinct, or an automatic action, which is maintained so long as life lasts. Congenital ills are 'those derived from the parents, and established in the child before birth ; they may be physiological, physical, or mental, or a combination of two or more. The word "heredity" has been used to express the idea promulgated in the bible that "the sins of the fathers shall be visited upon the children even to the third and fourth generations ;" thus scaring the public unnecessarily, because the public does not think, as a rule, or it would discover at once that the vileness of a pretended good god is exposed by his proposition to afflict the innocent, unborn and unconceived child because of a spite against the parents. A father may transmit to his child a syphilitic in- fection, but that is not any god punishing the child, it is a natural law, and when people understand how it works, they will either avoid acquiring such disorders, or, having them, will absolutely avoid procreation ; thus rational people can see that it lies within the power of man to defeat the alleged god who makes threats against his children. A child may be born deficient anatomically, yet Neurology will take it, and by natural methods often re- move anatomical defects, and nearly always eliminate 'the physiological troubles, thus proving that the spiteful gods are not in the running with those who understand Nature and her laws reasonably well. Deficiency may be mental, anatomical, or physiological, or a combina- tion of two or more. This is why a doctor must be posted with reference to possible causes, such as have already been enumerated. Debility in a child is often due to lack of preparation on the part of par- ents, particularly the mother, before conception and during the period of gestation. The mother may eat wrongly, or have insufficient food, or over- exercise herself, or commit many indiscretions through ignorance. We insist that the child has a right to be born well, and by that we do not mean simply its physical and mental condition, but that it should be born into comfortable surroundings and opportunities, and we believe that every male and female should be thoroughly informed on the subject at the very earliest possible age, which is about puberty. We know of nothing that has been fraught with such bad results to the human race as ignorance of the matter of pro- creation, and of sexual indulgence, and that ignorance has been intensified by an alleged "moral" code, prepared and promulgated by those who profess to believe a personal god engineers everything for the best, makes every- , HUMAN ILLS AND THEIR CAUSES 245 thing good, yet they commit "blasphemy" by asserting that the sex organs are obscene, subjects unfit for conversation between the sexes. Could any- thing be more silly? Infection, as we have shown, may be derived congenitally. It may also develop from wrong living without any "exposure" to any "contagious" disease ; or, it may be acquired by vaccination, anti-toxins, or any other form of serum therapy; or, it may be a result of accident, such as running a nail in the foot or a splinter in the hand ; or, it may be "caught" through using poisonous drugs. In any case of infection, of any sort, if the victim will take plenty of hot baths to keep relaxed, there will be no fever or congestion, and if he adds to that treatment restriction of his diet to fruit juices for a week, he will find the so-called attack a very light one. If it is a case of skin eruption, like small-pox, erysipelas, etc., a small sack of table salt dissolved in the bath water will save others from possible infection, although the danger is very slight in any event. Idiopathic ills are those which originate in one's own body from such derangements as those which cause indigestion, and many of the other symptoms called "diseases." Inoculation may be by accident or design. It means that anything which shocks or strains the nervous system, in such a manner as to bruise or lacerate, may develop infection. The rite of vaccination, and other similar practices, are monuments to medical ignorance, and the statutes- pro- viding for compulsory vaccination are disgraces to legislatures and courts who uphold their acts. The Illinois Supreme Court, and a number of others, have honored themselves, and protected thousands of people by declaring that "a healthy child is not a menace to its fellows in school," and that any school board which refuses such a child admission to school because it has not been vaccinated, is liable to a suit for damages by the parents. In England, where they "discovered" vaccination, and made compulsory laws in favor of the Doctor's Trust, the results were so appalling, as exhibited in the rapid increase of cancer, syphilis, erysipelas, and other malignant dis- orders, that they repealed the law, and all efforts to reinstate it have failed. American liars have asserted during the great war that inoculation against typhoid and small-pgx are compulsory in the British Army and Navy. I have a letter, dated May 10, 1916, from the office of the Registrar General, London, saying the story is a lie, that "the matter is absolutely voluntary, although the rite is accepted in the majority of cases." That is not astonish- ing in view of the ignorance and credulity of people. They say prayers too ; then they go into battle "damning Hell out of things." The mechanical body includes all parts which operate wholly or partially in a mechanical manner, whether it be locomotor or otherwise. The systemic body is divided in two classes, the internal and external, and each of these has the duality chemistry and mechanics. The internal systemic body comprises nerves and blood vessels, a digestive tract, a system of lymphatics, and several egestive provisions, in all of which mechanics is exhibited in the motions, from molecular vibration to osmosis, which is the passage of liquefied matter through the walls of vessels, and through the structures of tissues. A SYSTEM OF MATURE MEDICINE The organic body comprises the organs of special sense, the brain, lungs, heart, stomach, spleen, pancreas, liver, kidneys, bladder and sex organs. Some of these are mechanical and some chemical representatives. The eyes and ears are mechanical. The organs of taste and smell are chemical in their action. The lungs act mechanically to discharge carbon-dioxide, and take on oxygen, hence they are chiefly mechanical. The heart is mechanical, being nothing but a pump and a syphon. Internally, not only means within the cavities of the body, but it means within the cavities of structures within the body; also it refers to a position on the side of a body within the body, such as internal recti of the eyes, where we have also the external recti, and other muscles on the outside of the globe, all of which are called extra-ocular ; then we have the internal muscles of accommodation, etc., which are called intra-ocular. We also have the internal and external carotid arteries, and the internal and external iliac arteries, with veins to correspond. External is the opposite to internal in all respects mentioned above, and we are able to form some opinion about a person's condition from the ex- ternal exhibits ; but they are not final, nor analyzable, until we have gone the limit of a detailed examination. Sensory refers to not only the special senses, but the general sense of feeling, and it covers a very broad field. It is the connecting link between chemistry and mechanics everywhere in the body. It is mental, as well as physiological, and the mental dominates in a manner very fortunate for us, because it enables us to prove to people that many of their ills are due en- tirely to ignorance, and to a weakened condition of the mental sense by al- leged education, and we prove it in this way : Patients come to us with tales of woe that would make a cigar-store Indian weep; they evidently regard their ills as valuable assets ; they are even proud to report that all the doctors have said their cases are incurable, and so long as we tolerate it, they will rattle away ; we may s^ay all kinds of mean things about the bugs and the cruelty of the disease ; but when we tell them, blandly, they are cer- tainly in as bad a fix as they claim, and even worse than they realize, that their mentalities are in just as bum a condition as their physical bodies, they snort ; ego comes to the front, and, in their ignorance, they make the fool assertion that their mentality is all right. We then tell them that practically all insane people say the same thing. Then they get angrier, but when we tell them firmly, that we know all about their situation, and know it is so bad we do not want their cases at any price, they generally come down off their high horses and beg. Having won our point, we quickly proceed to clinch the case by getting a guarantee fee that they will follow instructions, and we win every case. The motor apparatus of the body is locomotor and vasomotor chiefly, although some people can work their ears, and all of us work our jaws. Also, as remarked before, too many wag their tongues, spreading vile tidings, and inoculating innocent persons with fake religions, ''morals," and other stuff, which amounts on the whole to the worst kind of a mental disease, developing the symptoms suspicion, jealousy, and all that goes with them. Real ills are those giving off physiological symptoms, which we find by HUMAN ILLS AND THEIR CAUSES objective and subjective, dynamic and static tests. They may be real body ills, or real mental ills. In either case both will soon be involved through their status of inter-dependence. Neurologists and Ophthalmologists are taught all of these details with great care, and, while we think our graduates are far and away superior to those of other schools, we regret to say that we frequently note a tendency to carelessness, not toward their patients, but toward themselves, among our graduates. We mean that they do not take the interest in adding to their fund of knowledge that they should. If this little "crack" at them will wake them up, and get them to work, the space is well given. Among the real ills are those caused by the emotions, and we have found that nervous strain through the mentality is about the worst form there is. It is like burning ammunition on the ammunition wagon ; it goes and there is no result except the loss of the ammunition. We seek to gain our pa- tients' confidences, and are often able to suggest something which diverts their attention from the cause of worry at least temporarily, and sometimes we have been able to make it permanent by reasoning with them, and by attending to the causes of their physiological derangements. One of the extreme forms of mental ills is hysteria. Speaking strictly, this would only apply to women, but it is usually used to describe mental excitability in both sexes. It varies in degree from that violence known as insanity to simple fits of temper, fear, hilarity, etc. Such patients are some- times hard to get under control, and we have to be very firm, but so far as their deranged physiology is concerned, they are comparatively easy. The other extreme of mental troubles is melancholy, which is bad be- cause it is a condition far below normal. Patients often lose ambition to get well, and if we cannot restore it after a few weeks, we may still be able to partly restore the physiological body; but such are not easy cases by any means. Happily, there is a class who are intermittently hysterical and mel- ancholy, which is analogous to clonic spasm physiologically, and our efforts in both hysteria and melancholy is to get that intermittence going, when our case is practically won. Accidental, as used in the diagram, means incidental as well as the popular understanding of the word. Accidental real mental ills may come from the shock of fright, or from the receipt of appalling news, and there have been cases reported in which patients died instantly; but we do not believe such effects possible if the physiological body is in good condition. Strain upon the nervous system through the mind may be -accidental, that is, it may come to a person through no fault of his own, and it may be so great as to simply exhaust the nerve supply. Just how it is done no- body has yet discovered any more than they have discovered how certain chemical elements control the rearrangement of other elements in forming new combinations ; so far as the physical exhibit goes, they take no part in it, yet we know they are necessary because the other combination will not take place unless those elements are present. False illnesses are very common, chief among which are those who have been reared on the theory of hope and fear; who are so ignorant and A SYSTEM OF MATURE MEDICINE heedless that they listen to everything every gabby person says, anft with a peculiarly constituted mental apparatus, their sympathy develops what every- body else has, either in order to be popular, or to give a physical demonstra- tion of their sympathy. Some are actual malingerers, and we believe we have the only system of practice that will catch them. We have had a lot of fun with this class and have done a lot of good, gaining the thanks and appreciation of the afflicted relatives and friends. Education along false lines predisposes people to certain classes of ills. In the old schools of medicine, it is notorious that the majority of students develop symptoms of nearly all the ills the lecturers talk about during the first year, and many find themselves so totally unfitted for the work they drop out, never finishing the course. Another sort of education is environment, that is, where people are hearing all kinds of complaints ; reading silly newspaper stories, particularly by the "health editors" and by city health commissioners, who are usually cheap doctors and tricky politicians. Education and environment have sometimes a benign effect, that is peo- ple only have mild cases of disease-phobia, and with a little reasoning, either through circulars of information, or personal talks, they recover before much damage is done. On the other hand there is a malignant development in some people to such an extent that if told they have been "exposed" to small-pox, they will develop cases in a few days. Happily there are only a few who are so easily affected bodily through the mind, but there are thousands, yes, hundreds of thousands, whose mentalities develop something analogous to small-pox sim- ply through fear superinduced by credulity. They are permitted to run at large, but are liable to become violent at any moment. Positive influences may be good or bad. The patient is generally affected by the bad one, and we must produce the antidote in our own positiveness. If we can make a patient's position, with reference to his imaginary ills, absolutely ridiculous, we can win all the time. Then there is a negative class who develop imaginary ills from subtle influences in a sort of a negative way. As a rule, they are dull, could not see a joke until the next day; could not learn mathematics of the simplest kind in any time ; they are devoid of imagination. Our only possible nega- tive treatment of these people would be to refuse to touch the cases. Neu- rology is always positive, and positive to the last ditch. This is the reason we insist that all students in our school make a grade of 100 per cent, in physics in order to graduate, and it must not be understood for a minute that our physics is a simple thing. The first hundred pages of this book will give a fair sample of what our physical optics is, compared with others, and when it comes to physical chemistry, we have greater complications. But people who know physics, know how to be positive and make good. Causes of human ills have been classified in ten departments early in this chapter, and all of them have been condensed into the proposition, nerve shock or strain. The second diagram subdivides the subject of causes, and the words apply in a general way, at least, in accordance with the coming paragraphs : HUMAN ILLS AND THEIR CAUSES 249 Chemical causes are in considerable variety. These may be divided into two classes; Congenital and acquired, and each of these is subject to further divisions, as will be shown. Body chemistry is a very complex thing. It may be put in a state of confusion by the presence of too much of one ele- ment or not enough of another. This has been one of the great weaknesses of old-school medicine. They paid no attention to the chemical qualities of food, and do not know enough about the subject to realize the possibilities of combinations of food and medicine to develop very dangerous conditions. They have learned that when they give mercury, the patient should not eat sweets or sours, nor drink hot or cold drinks, but that was no more than any layman might learn by experience. We teach our Ophthalmologists a sufficient abstract of dietetics so that they know how to keep their patients going in the right direction in food matters, although it is not possible in the Ophthalmological course to give details chemically, because it is necessary to know more about general anatomy and physiology. Hence, only Neu- rologists are able to call themselves dieticians, and we advise them not to do that, but to refer to their dietetics as Neurologists' Materia Medica. For the same reason that we have congenital ills, there must be con- genital causes, and they have been mentioned in a preceding paragraph as a deficiency and debility resulting from improper care, education, diet, and general habits of living. The mentality as a factor in causing ills, congenital or otherwise, is a very potent one. Mothers may brood over troubles, or be mentally affected by gossipy neighbors, during the period of gestation, or a child, while grow- ing up, may have foolish advisers, or foolish parents who neglect to advise them at all, and may allow his passions to get him into trouble, or his emotions may be involved until his mentality is warped. Mental shocks upset the nervous system almost as badly as a rule, and sometimes worse than any physical shock would. As stated elsewhere, we do not believe that if a child was rightly reared, and his physiological errors corrected, there would ever be any danger of death from mental shock. We teach our students and our patients to cultivate a fine mental control, which will render them immune from such bad effects. To illustrate this, I have had the shock of losing two sons within a week from diphtheria, which baffled the old-school doctors in charge completely. One of the boys was seventeen, and the other fifteen ; the elder one died standing on his feet, holding me by the coat lapels, and begging me to save him he was chok- ing to death from antitoxin. The other died just a week later from kidney trouble, which frequently follows diphtheria. If I had not cultivated self- control, those deaths and surrounding circumstances would have unbalanced my mind, but I reasoned, and that saved me. Not only that; it made me determine to go ahead and study and develop what was then a system of optical practice into a system of general practice, which would be so nearly perfect it would teach people how to live so they may be completely immune from all such possibilities. It is still a fact, however, that no one has ever yet found a specific cause for the so-called childrens' diseases ; they develop from obscure causes and run their course quickly. We are able to say that there has not been a case of diphtheria, scarlet fever, measles, mumps, or 250 A SYSTEM OF MATURE MEDICINE anything similar in any of the families who have lived Neurologically during the last seventeen years. Therefore, we believe we have the nearest a per- fect system that has ever been offered. Mental strain sometimes comes without shock, and sometimes follows shock. One of the commonest causes of strain is familiarly known as the "green-eyed monster," jealousy. This is the most annoying, disgusting exhibition of self-love that we can conceive of. Some have claimed jealousy of :-- I-" 7 r _: :- ' r.-:i n :,;-' : '.-.-*' ~ ---. or Mkid irr - - Ml - - - - :, f - - V: : -.- - - - - - . - : - - 7 -- ------ - -- , 132, MS :- r.'^...;f- _ __, -- :-:i r* : -: :_- I . : r x - '-. :' ": EH -Merriy fittvp :-. V -. :-- f :-: -:-T:-::T- i --.- : - : >: ;.:,: :, .-. Bag Asa 42 : . - : -; i:v :r 1' -: ' -... ". : - - - - Bi-cercx 5T, . 27 - : : 1-.-- : - : v. -: - : --. - a .- *: - -- 9 1SS m 316 A SYSTEM OF MATURE MEDICINE Oblique muscles 268 Oblongata 123 "Old man Fog" 209 One minute angle 144 Operations, criminal 202 Opium habit 207 Ophthalmology 10 to 300 Ophthalmologist 119 Ophthalmometer 106 Ophthalmoscope 106, 197 Optical Axes 99, 135 Centers 29 to 99 Density 14 Firms 56, 276 Journals 56 Truths 5 Optic disc 132 Optic nerve 126 Optic neuritis 198 Optics 13 to 116 Optics, diagram of 9 Order of presbyopia 153 Organic chemistry 119 Organic body 246 Organic ills 254 Orthodox '"freshies" 207 Orthophoria 149 P Pacchionian body 122 Palpebrae, elevator 126 Palpebrarum, orbicularis 133 . Paralytic squint 186 Patients' condition 161 Penalty 235 Period of variations 156 Perpendicular-parallel 22 Petit, canal of 129 "Phenomena of vision" 221 Physical eye 93 Physical optics 13 to 116 Physics, defined 11 Physics of retinascopy 101 Physiognomy 261 Physiology, nervous 119 Pia mater 122 Pin-hole 266 Pituitary body 122 Planes, cardinal 43 Planes, conjugate 30 to 79 Plexuses, nerve 121 to 125 Plus impulse 150 to 159 Pneumonia 239 Points Cardinal 43 Conjugate 30 to 79 Focal 29 to 99 Near and far 138 to 145 Nodal 41 to 97 Principal 44 to 53 Rays from 25 Poles of eye 89 Poly-want-to-uria 234 Pons Varolii 125 Possible results 152 Posterior chamber 132 Posterior staphyloma 132 Power Creative 119 Cylinders, all degrees 64 Eyes 93 Lenses 44 Pow-wow with mirrors 216 Practice and theory 155 "Precision" instruments of 106 Preliminary remarks 5 Presbyopia 131, 153, 282 Prescription writing 87 "Press Bulletins," A M A 226 Primary cause 6, 140, 186 Primary colors 256 Primary meridian 172 Principal meridian 172 Principals, cardinal 16 Prisms Angles of 21 Construction of 21 Deviation of 21 Physiological action of 175 Tests with 149 Progressive myopia 201 Pull, negative 133 Puncta lachrymalia 133 Punctum proximum 89 Punctum remotum 89 Ouality 197 Quantity 197 Questions 106 R Radii 29 to 99 Range of accommodation 138 Ratio of indexes 14 Rays, lines representing 15 Real ills 246 Real images 37 Relation of special senses 222 Reflection 17 to 39 Refraction Denned l.i Eyes 93 Indexes of 14 Lenses 41 to 92 Plane surface 13 to 20 Prism 21 to 27 Reflection 17 Registration 159 Remarkable "xperiments 283 Results, possible 152 Retina Em., Hy.. My. 89 Layers of 132 Normal 196 Retinal arteries 128 i Retinascopy, a joke 168 Retinascopy, physics of 101 Retinitis 198 Retreating forehead 263 "Rheumatism" of eye 194, 232 Rods and cones 132 Rules 14 to 99 S Sac, lachrymal 133 Scales, bi-focal 83 Schlemm, canal of 129 Sclera 129, 193 Sebaceous glands 13." Secondary axes 37 Second object 142 Secondary meridian 172 Sectional eye 129 Sections of rays 15 Seeing 219 Segments, bi-focal 83 Senile cataract 190 Sensation 121 Shadow movement 105 Shadow test 101 Sheaths 126 Shock, mental 249 Short focus 29 Single curved surfaces 29 Single perpendicular 19 Sinuses 122 Skeleton bridge measures 224 Smallpox 232 Smelling 219 Spaces of Fontana 130 Spasm, nervous 149 to 171 Spastic squint 186 Special sense 125, 219 Specimen cases 161 Sphincter muscle 131 Sphenoid, wings of 127 Sphenoidal fissure 127 Spherical aberration 34 Sphere-cylinders 49 Spherical lenses 41 to 79 Sphygmomanometer 211 Spinal nerves 121 Spirit of plague 208 Squint 186 Standard eye 93 Stages of retinitis 199 Standards in practice 285 Staphyloma 132 Statements, false 44 Static condition 149 Static nerve test 181 Stenopaic disc 151 Stethoscope 211 Strain, mental 249 Strain, nerve 140, 247 Striated muscles 134 Stye 133 Supercillii. corrugator 133 Supply, blood, nerve, of eye 128 Suppuration 140 Supreme Court decision 254 Sylvius, aqueduct of 122 INDEX 317 Sylvius, fissures of 123 Symptom classification 162 Sympathetic system 121 Syphilitic retinitis 199 "Synopsis of Neurology" 5 System, body 245 System, nervous 119 Systemic cataract 185 T Tables, neurometric 157 to 171 Tapetum nigrum 128 Tasting 219 Tear duct, closed 203 Teeth 148, 262 Telegraph code 220 Temperament 160 Temporary lenses 150 Ten causes of ills 242 Tensor tarsi 133 Tentorium 122 Tests Cyclophoria 173 Dot-and-line 180 Duction 179 Muscles 182 Nerves 182 Refraction 143, 205 Test types 144 Tenon r s capsule 127 Theory and practice 155 Therapy, diagram of 181 Thickness of lenses 279 Thrombolism 199 Tinitis aurium 236 Tissues, connective 127 Tonic spasm 154 Toric lenses 81, 281 "Trachoma" 200 Tract, uveal 127 Transposition 87 Tri-curved lenses 81 Traumatic cataract 195 Trusts 6 Tyndall 9 U Ulceration 140 Unfogging 157 Units of measure 22 to 44 Uveal tract 127 V Vaccination 208, 233, 254 Vaccine, hay fever 293 Variation, periods of 156 Varolii, pons 125 Veins 123 Vena vorticosa 130 Ventricles 122 Vertebral arteries 123 Vigor of youth 154 Virtual objects 37, 67 Vision, classes of 148 Vision, tests of 148 Visual axes 99, 135 Vitreous humor 129 Weakness, nervous 149 Willis, 'circle of 123 Wings of sphenoid 127 Work, extra 158 Xerophthalmos 204 Young 7_ Youth, vigor of 154 Zinn, circle of 130 Zinn, zone of 131 W LIST OF ILLUSTRATIONS Page Perpendicular-parallel method of measuring refraction 15 Circle method of measuring refraction 16 Chord-arc method of measuring refraction 17 Base-line method of measuring refraction 18 Single perpendicular method of measuring refraction 18 Same applied to several refracting media 19 A cross-eye case 20 Form of prism 21 Angles of construction and of deviation of prisms 22 Same by baseline method 23 Showing calculation of apex of angle of deviation 24 Showing apparent displacement of objects by prisms 25 Showing dispersion by prisms 25 Showing how dispersion is eliminated 26 Two combinations of prisms in one drawing; figures apply to both 26 Similar drawing showing positive and negative focuses 27 Showing how prism principles are involved in lenses 27 A cross-eye case 28 Refraction by single curved surfaces 32 Focus by a single curved surface 32 Negative focus by single curved surface, reversed 33 Different focal points by central and edge rays 33 First and second principal focal distances by single curved surfaces 34 Principal focal distance by reflection from concave surface ''>'> Conjugate focuses by single curved, convex surface 35 Guide-line method of locating conjugate ' focal points 36 Conjugate focus by reflection from concave surface 36 Formation of images by single convex surface 37 Virtual object, reduced by single, concave surface 37 Virtual object, enlarged by single, convex surface 38 Formation of images by concave mirrors 39 Magnification of objects seen in concave mirrors 40 Minification of objects seen in convex mirrors 40 Refraction by plano-convex lenses 41 Same with variations 42 Perpendicular method of locating optical centers 43 Perpendicular-parallel method of locating optical centers 43 Negative focus by reflection from convex surface 43 Showing the true principal focal point on flat side of plano-convex lens 44 Showing relative focal distances of different lenses 45 Illustrating "an interesting exhibit in conjugate focuses" 47 Law of single curves used for finding conjugate focuses 47 Showing segment of a cylinder 48 Showing meridians of cylindrical surfaces differ in power 49 Showing forms of -4- and cylinders 50 Refraction by plano-concave lenses 51 Showing first and second negative focal points of concave lens 52 Showing ray entering flat surface of lens only suffers refraction once 52 Showing optical center, nodal point, secondary axis of concave lens 53 Conjugate focus by reflection from plano-concave lens 53 Formation of image by reflection from plano-concave lens 54 Virtual object as seen through a .plano-concave lens 54 Refraction by bi-convex lenses 57 Refraction and formation of image by glass globe 58 Principal points and planes of a bi-convex lens 60 Formation of images by bi-convex lenses 60 Showing how location of object fixes position and size of F 2 62 Showing spherical and cylindrical surfaces of a bi-convex lens 63 Refraction by bi-concave lenses 65 Optical center, nodal points, negative principal focuses of bi-concave lenses 66 Virtual object seen through a bi-concave lens 67 Spherical and cylindrical surfaces of a bi-concave lens 68 Refraction by + meniscus lenses 69 Refraction by meniscus lenses 70 Comparison of structures of -f- and meniscus lenses 71 Principal focal distances of a -j- meniscus lens 73 LIST OF ILLUSTRATIONS 319 Page Principal focal distances, negative, of a meniscus lens 74 Details of calculation for a + meniscus lens 75 Details of calculation for a meniscus lens, negative focuses 76 Advertised lenses shown to be faulty in construction 77 Conjugate focal distances of a + meniscus lens 78 Two crosseye cases 79 Three pictures of the same cross-eye case 80 Showing a true tpric surface, sphere and cylinder on same side of lens 81 Comparison of bi-convex and meniscus sphero-toric lenses 82 Comparison of meniscus with bi-convex bi-focal lens 84 Showing very strong lenses could not be made meniscus form 84 Showing the same proposition as could be made bi-convex 84 Showing ordinary form of meniscus could be' made, but is not good 85 Showing several forms, surface and edge of freak lenses 85 A cross-eye case 86 Protractor for finding the exact axes of cylindrical lenses 88 Showing principal and secondary meridians of a cylindrical surface 89 Emmetropia, hyperopia and myopia 89 Showing myopia is the only condition having a far point 90 Showing the focal points in the several eye defects 90 Compound hyperopia 91 Showing steps in correcting the above 91 Mixed astigmatism 91 Show-ing steps in correcting the above 91 Posterior surface of crystalline lens and its focuses 93 Anterior surface of crystalline lens and its focuses 94 The crystalline lens as a whole, with its focuses 94 Crystalline lens enlarged, beginning construction of a sectional eye 95 Showing the physical construction of a sectional eye 96 Retinascopy with plane mirror ; emmetropic eye 101 Same ; hyeropic eye 102 Same ; myopic eye 103 Same, with concave mirror ; emmetropic eye 103 Same ; hyerpoic eye 104 Same ; myopic eye 104 Retinascope and ophthalmometer 106 Relation between eyes ; arrangement of muscles 126 Sectional eye, enlarged 129 Mechanism of accommodation 137 The emmetropic eye, at rest and accommodating 145 The hyperopic eye. at rest and accommodating 146 Same with correcting lens in position 146 The myopic eye, showing its far point and where parallel rays focus 147 Same with correcting lens in position 147 Astigmatic chart, reduced 152 Cyclophoria and oblique astigmatism, simulated in spasm 171 Same, with exhaustion of the nerve supply 172 Same, with real oblique astigmatism, but out of position from spasm 172 Same, with displacement reversed on account of weakness 173 Prism chart for measuring actual deviations of the eyes under i static test 175 The ophthalmoscope 188 A pterygium 188 A cataract 188 A normal retina 196 The author's ophthalmoscope 197 A case of neuro-retinitis 198 Albuminuria (2 pictures) 199 An embolism 199 A haemorrhage 200 Cupped disc 20O Image in emmetropic eye 220 Telegraph code 220 How a printer reads type 220 Image in front of retina in myopia 221 Image would be behind retina in hyperopia "if it could be formed 221 PRINTERS KABLE BROTHERS COMPANY MOUNT MORRIS, ILLINOIS MSS RETURN OPTOMETRY LIBRARY TO* 490 Minor Hall 642-1020 LOAN PERIOD 1 F^MF IKC 2 f 3 4 5 6 ALL BOOKS MAY BE RECALLED AFTER 7 DAYS RENEWALS MAY BE REQUESTED BY PHONE DUE AS STAMPED BELOW UNIVERSITY OF CALIFORNIA, BERKELEY FORM NO. 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