IMAGE EVALUATION TEST TARGET (MT-3) 1.0 I.I Ui»2A |25 Ijg ^^ ■■■ 2.0 lU Ki lis 14.0 IE i^^li''* 1!-^ ^ 6" -^ HiotogFaphic Sciences Corporatton 23 WIST MAIN STUIT «VIISTIR,N.Y. 14SM (716)t72-4S03 CIHM/ICMH Microfiche Series. CIHM/iCIVIH Collection de microfiches. CaiMdiah ImtituM for Historical Mieroroproductlom / liwUtut caradlon do mlcroroproductlom hittorlquoo Tachnical anci Bibliographic Notas/Notas tachniquaa at Mbliographlquaa TlH toi Tha Inatituta haa attamptad to obtain tha baat original copy avallabia for filming. 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Original copiaa in printad papar covars ara filmad baglnning with tha front covar and anding on tha last paga with a printad or illustratad impras- sion, or tha back covar whan appropriata. All othar original copiaa ara filmad baglnning on tha first paga with a pr!nl«d or Illustratad impras- sion, and anding on tha last paga with a printad or illustratad imprassion. L'axamplaira film* fut raproduit grica A la g4nAroalt* &r. BibliothAqua nationals du QuAbsc Las imagaa suivantas ont At* raproduitas avac la plus grand soln, compta tanu da la condition at da la nattat* da l'axamplaira film*, at en conformit* avac las conditions du contrat da fllmaga. Las axamplalras originaux dont la couvartura en papier est imprim*a sont fllm*s en commenQsnt par la premier plat at en termlnant soit par la darni*re page qui comporte une empreinte d'impression ou d'illustration, soit par le second plat, salon la cas. Tous las autres exemplaires originaux sont film*s sn commanpant par la praml*ra page qui comporte une empreinte d'impression ou d'illustration at en terminant par la darni*re paga qui comporte une telle empreinte. The last recorded frame on each microfiche shall contain the symbol — ^- (meaning "CON- TINUED"), or the symbol ▼ (meaning "END"), whichever applies. Un des symboles suivants apparaftra sur la darni*re image do chaqua microfiche, sslon le cas: la symbols — ► signifle "A SUiVRE". le synibole ▼ signifle "FIN". Maps, plates, charts, etc., may be filmed at different reduction ratios. Those too large to be entirely included in one exposure ara filmed beginning In the upper left hand corner, left to right and top to bottom, as many frames as required. The following diagrams illustrate the method: Les cartes, planches, tableaux, etc., peuvent *tre film*s * des taux da r*duction diff*rents. Lorsque le document est trop grand pour *tre reproduit en un soul ciich*, 11 est film* * partir da Tangle sup*rieur gauche, de gauche * droite, et de haut en bas, en prenant le nombre d'imagas n*cessaire. Les diagrammes suivants illustrent la m*thode. errata I to s palura. ion * n 32X 1 2 3 1 2 3 4 5 6 ^aF/ \imm TiJ i: N vTURE OF rni: mokimd roisoxXs, AM) HE DISEASES TO WHICH THEY GIVE RISE ; Ur.IM. A.N INAUCrJMr. DISSKUTATION I'UKbK.NIKI' III Tin-: .MIiniCAI, I'ACI r;!'\ (M' MrCIL!. ( ollkuj:, ?,IAUC1I I, l^.')!. iMUiiu 1(1 iii;(Ki\ IN!, riir. dkciu;!' or noc'iu! or mciihim: and siuckuy. :!v ROBERT CRAIK. .MONT HEAL : riinted ;it llie Ollico ol'tlio ]Mc(licul Chroiiick', l*^ St. Fraucoisi Xavier Street, by jNIooke, Owleu iV Stkyk.nsox. 1851-. C64t/>a r^ij- ^ '■°;** ■*"/■'„■ m 1 • THE NATl JIK OIVTIIE MOlllUD POISONS, AM) THE DISEASES TO WHICH THEY GIVE RISE ; BKING AN INAUGURAL DISSERTATION rUi:SENTED TO t THE aiKDICAL FACULTY OF McGILL COlalJlGlL MARCH 1, 1854, r-KlOR ro BECKIVING TlfE REGREE OP POCTOn OF MEDICINE AND SURGERY. BY ROBERT CRAI K. • . • . • _ ' MONTREAL : Printed at the Office of the Medical Chronicle, 42 St. Francois Xavier Street, by Moore, Owler &; Stevknson. ■ , 1854. .>1 w i Ml jj /■ J TO ■ WILLIAM FRASER, M. D., I'rulessor of Institutes of Medicine in McGill College, AND TO THE OTHER MEMBERS OF THE MEDICAL FAGULTT OF THAT UNIVERSITT, THE FOLLOWING PAGES ARE DEDICATED, AS AN ACKNOWLEDGEMENT OF DEEP OBLIGA'I'ION FOR THE JiENEFIT DERIVED FROM THEIR VALUABLE TEACHING, AND FOR NUMEROUS INSTANCES OF PERSONAL KINDNESS, By their grateful frien.l and former Pupil, I . THE AUTHUil. 56203 P R E V A (• i: . -. -.•!.-*, ^■. The present Essay was written durinji tlie progress of a College Sos- «ion, in the intervals of close attendiinco ;it tin- I.c.'linv.s, and ^vitll(Hlt Jiuy view towards future publication, i'roris.sui' ^Vl•iilllt, lioM-ovir, lor ■vvlio.se judgment I entertain the highest, rrspcft, and to whose scrutiny it was submitted, was pleased to mention it in terms ul'a[)proval, and t<) express a hope that it might be put in a Ibrm suited liir general circula- tion. These views having been shared by other members of the Va- cuity, and the Editors of the " Medical Chronicle" having kindly ofl'ered to publish it in their .fournal, 1 was induced to lurni^h a copy fur that. purpose, and also to produce it in this se})arate lurin, not as possessing any great claims on public attention, but as containing some ideas that •may at least repay the trouble of a perusal. Montreal General Hospital, ) September, IS")*. \ A -x future 0f i\ t 0150115 AND OF THE DISEASES TO WHICH THEY GllfE RISE. BEINfJ AN INAUGUnAI, DISSEHTATION PUESKNTED, MARCH 1854, TO THE MKDICAI. FACUI-TV OF M'GILL COLLEUn. BY RO BERT CRAI K. College Ses- nul ^vitll«llU luwevtr, tur CISC scrutiny rovul, uiul tt) eml circuln- s ol; the Va- iiiully oQori'tl copy ibr tlr.it us pussessiiiL^ no ideas tluU It is not riiy intention in the following pages to attempt an elaborate description or explanation of all the phenomena connected with the di- seases produced by the morbiil poisons. The subject is tbo extensive to be included within the narrow limits of an inaugural dissertation, and too abstruse and intricate to be undertaken by any ttit those whose minds have been trained by long habits of research and discrimination. But there are certain prominent points that stand out as landmarks,' challenging the attention of every observer, and which have been sub- jects for investigation to men of science, ever since Medicine deserved the name of a science. Some of the most remarkable of these features, for instance, are the contagious nature of the diseases to which the morbid poisons give rise ; the great disproportion between the cause and the effect ; the immense multiplication or reproduction of the poison within the system; the re^ gular sequence wtiich the Symptoms generally preserve; the immunity from a subsequent recurrence which many of them have the power of conferring ; together with other peculiarities less prominent, but scarcely less characteristic: It is the consideration of liome of theSe prominent features, including the nature of the morbid poisons themi^elved, that I propose as the subject of the following essay. I do not intend to take them up sefiatim, in the order in which I have just enumerated them, but as they suggest themselves in their appropriate places as I proceed. In the examination of the subject, cursory as it must necessarily be, I shall pass lightly over those parts which may fairly be considered as settled, and enter mnre fully into those which still remain in obscurity, alluding briefly to the various theories which have been advanced by difTereut authors, stating the objections to them, and in some cases ven- turing to suggest others which may seem more strongly supported by f ] H i I analugy, and which nmy e?(iiluin as fully the vnriuus |)heiioinena under consideration. Of tho natnrs mrulc use of by iiiitlidrs to (Icsi'jrniitc tlir fliuss of disonscs produced by the iu'lioii uf the iiiorliid iioisoiis, tlie ttrni ♦' /yiiiotic" seems the least oliji-ctioiiiiMe, mid 1 >liiili tlurifi>re iidopt it. (,'u I leu's order of exanthcmuta iiieliidis niiiiiy ol'tlicrii, hut not tlie whole, so also the term contagions or infections tiiseasi-s. tlionuh it wonid ineliule all the diseases in question, yet it would coni|)reliend others, as scabies, jiorrigo, and such other diseases as from Iheir |tnrcly local nature arc not geneinlly ranked in the same class with the ollu-ry. The division of the subject which I shall ado[)t will be the follow- ing :— Firstly, I shall consider the scat of tiie zymotic diseases. Secondly, The conditions necessary or favourable to their production. Thirdly, The probtdjle ntiture of the poisons tlunuselves, and their mode of action, which, together with the preceilnifj; divisions, will include the explanation of most of the phenomena of the diseases. Lastly, I shall conclude byalludin of time become lessened or obliterated, and indurations become softened and removed, so also the altered constitution of the blood produced by these diseases, may in pro- cess of time gradually subside, and iinally altogether disappear ; thus accounting for the wearing out of the jirotection afforded by vaccination, and the recurrence of small pox ox measles, a second or even a third time. A strong reason for supposing the susceptibility to these diseases to depend upon the effete matters of the tissues, is, that the accumulation of these matters in the system is well known to create a predisposition to the attack of epidemic and contagious diseases; thus, these diseases are generally found to break out first, and to be most severe, in those locali- ties where impure air, imperfect ventilation, &;c., prevent the proper elimination of these matters from the blood. So also with great muscu- lar exertion, from the waste which it causes in the ti-sue. The influ- ence which these matters have in promoting the tendency to the acces- sion of zymotic diseases, with the conditions which favor their accumu- lation in the system, are well given in a paper by Dr. Carpenter, an T^ !>,. irards either gives strong the salts cac or material it will be les, some of 5e, when re- ;erials of t^e these might 3ur only once diseases, that ular period of oal pathology, calls — the as- of a par has :c., the altered lire to be per- \exi the consti- lases, this assi- formorly main- I cases to return me lessened or ,ed, so also the ses, may in pro- disappear ; thus 1 by vaccination, or even a third lese diseases to e accumulation predisposition to ese diseases are , in those locali- ze nt the proper ith great nniscu- me. The iuflu- ,cy to the acces- ir their aocumu- )r. Carpenter, an isk abstractor which maybe found in " Braithwaite's Retrospect," (Part xxvii.) But, as before hinted, neither can this specific internal cau^^e be looked upon as sufficient in itself to produce the disease, notwithstanding the many persons who believe that these diseases may be, and often are thus produced, or how could the fact be accounted for, that villages, towns, and even continents have remained not only for years but for centuries free fro^i them, so long as the inhabitants avoided all communication with those laboring under the diseases. That the snme specific internal cause existed in these individuals, cannot be denied from the great rapidity with which the diseases were wont to spread, when once introduced by in- fection or contagion. With these facts before us, it is difficult to admit that these cases occur without any external c^use, which are from time to lime breaking out in localities apparently cut off from all sources of infection ; for, taking into consideration the subtile nature of these poi- sons, their diffusion through the atmosphere, and the length of time they may remain in a dormant state in fomites and in other situations, it is more than probable that these anomalous cases owe their origin to some lurking infectious matter, which has been unwittingly communicated, and which has really kindled the flame ascribed by many to spontanea ous combustion . On the other hand, it js most difficult to conceive how these diseases first originated, if we do not admit their origin independently of conta- gion. We have no record of their having existed from the creation, the history of most of them dating back no farther than a few centuries; hence we are constrained either to admit that they have arisen without any external cause, or to seek for some way of reconciling their present prevalence with their former absence or obscurity. The reason;; why the former admission cannot be made, have been already given } with regard to the latter circumstance, nothing can be brought Iprward except conjecture. We are aware that there are many agencies, such as time, and a vari- ety of circumstances, which exercise a powerful modifying influence on many things, and even on diseases themselves. Plants have been taken in their natural state from their native forests and plains, and by the foiceof circumstances arranged by ^nan's ingenuity, have been trans- formed in the most wonderful manner. The same maybe said of many of the lower animals. Man himself has undergone various changes, both in his physical and moral constitution ; and even those ve^-y diseases of which we are now treating, have, at various periods of their history, pre- sented characters widely different from tliose presented at other times ; * ; 1 : \ i I ;r 6 in fact, no two epidemics of the same disease can be said to hare been perfectly alike in all their characters. Is it not reasonable, then, to infer, that these diseases have been at one period of their history very different from what they now are, so different indeed, as to render their recognition as the same diseases highly im- probable, if not impossible. (It has been all but proved that small pox is greatly altered by trans- mission through the system of the cow. If this be correct, then, may not the systems of other animals possess the same transforming power over many of these diseases, some of them rendering them milder, while others render them more virulent ; and might not even those diseases, now so distinct, and in many cases so malignant, have first existed as obscure and perhaps trivial disorders in some of these lower animals, and by various circumstances, have become developed and altered until their present condition has been attained. This suggestion is somewhat ima- ginative, and might almost be called chimerical ; but it is not destitute of probability, and it is offered in a case where actual proof is out of the question.) Taking it for granted then, that two causes of a specific nature co- operate in the production of these diseases, one of them existing within the body, and the other introduced from without, we have a clue to the explanation of many of their peculiarities. It explains the reason why small pox should in general be so much more mild when communicated by innoculation than when contracted by accidental infection, for the blood of those who take the disease in the latter way must be supposed to contain the specific matter in large quantity, and hence the disease is severe, while inoculation will produce the disease in those who!,e blood contains the matter even in minimum quantity, and in whom the di- sease will be proportionately slight. For the same reason, those first attacked during an epedemic have the disease more severely than those attacked at a latter period, for the greater liability to the infection in the former, is caused by the large amount of the specific material in the blood. As already shown also, it explains the protection afforded by many of those diseases against their future recurrence. III. — Wc come now to consider the probable nature of the morbid poisons themselves, and their mode of action. Although it may be very evident, that two causes of a specific nature are concerned in the production of these diseases, it is not so evident in what these causes respectively consist, or in what way they react upon each other. One of them has already been considered, it now remains for us to consider (he other, and their mutual reactions. i *l hare been e been at one •e,so different s highly im- rcd by trans- ct, then, may iming power milder, while lose diseases, list existed as r animals, and red until their )mewhat ima- s not destitute )f is out of the fic nature co- xisting within e a clue to the e reason why communicated ection, for the it be supposed 3 the disease is se whose blood whom the di- pedemic have period, for the I by the large ' shown also, it against their morbid poisons specific nature so evident in hey react upon it now remaio9 Various theories have been proposed in explanation of Ibf se oLscure and difficult points, but the most important hitherto brought forward have been, Liebig's fermentation theory, and the parasite theory of Dr. Holla'd and Professor Henle. I ig compares the action of the morbid poisons on the blood to that of y. lot on the sweelwort during the process of fermentation. He points out the close analogy which exists between the two processes, the phe- nomena being so similar as to a])pcar at first sight almost identical. This theory is so familiar to all, that it would be needless repetition to detail it here. An excellent abstract of it is given in Dr. Watson's lectures, under the head of Exanthemata. Simon, in his lecture on the morbid poisons, summarily condemns this theory. lie denies that the two actions are at all analogous, because, in the first place, the morbid poisons are very various, affecting the different ingredients of the blood severally and distinctively, while yeast is the only ferment capable of reproducing itself in the vegetable solution, and its action always gives rise to the same products. I need scarcely say, that this argument, however strong it may be against the identity of the actions, does not in the slightest degree affect the analogy. In the second place, he objects that their sphere of action nowhere extends beyond the particular ingredients which they respectively affect to an entire fermentation of the blood. This objection also is overstrain- ed, for the analogous part of the process of fermentation is the reproduc- tion of the yeast, and not the production of alcohol and carbonic acid. The morbid poisons extend their action to all the ingredients of the blood susceptible to their influence, the mass of the circulation being protected by the vital power of the system. The action of yeast extends no further. If the solution contain matters not susceptible to this ac- tion, — under the control, it may be, of some power stronger than that of the yeast, that of chemical affinity for example, — these matters remain totally unaffected. Thus the blood may be said to undergo as complete a change as the sweetwort, although the change may not be so practically demonstra- ble ; but have we not sufficient proof of such a change, in the fact, that it now possesses a power which formerly it did not possess, namely, that of resisting contagion. The fact that yeast is an organic production, instead of a chemical sub- stance, as Liebig probably supposed it to be, is a stronger objection to the theory, as a theory, than any of the foregoing, for, from a chemical, it becomes changed into a parasite theory, a consummation which Liebig cannot be supposed to have either foreseen or intended. . Uit whatever may be the defects of this theoiy, it has served to call r ' , ! '• ! ^ : ! i ; ! 1 ( '. : 1 1 ■i attention to a striking analogy u'hich had before been unnbticed, it has given definiteness to phenomena which were before vague and obscure, and it has pointed out the direction m whibh future investigations would be most probably attended with success; Aftei- condemning Liebig's theory as inapplicable, Simon throws out a few sliggbstions of his own, regarding the phenbmena of these diseases. He Says, " in many respects they Seefn ib be sui generis. Certainly they are bhemical." Now, he brings no reasons tt» show why the phenomena should be looked upon as chemical, nor fcan I conceive why they should be considered as suchj for they ceriainly have no analogue anfiong ordin- ai-y chemical actions, ptoperly so called. Pfbceeding from this assump- tibh, he next assigns them a plhce among that class of actions styled ca- talytic, with the condition, hotvever, that if infeluded in this class, they ihust constitute a new species; Now, whateveir be the nature of the action which the morbid poisons exert upon the blood, it seems sufficiently clear that it bannot be cataly- tic, seeing that an essential law of catalysis is, that the agent which produces such abtion should not itself enter into any combination resulting from that action. The actibn of yeast in the alcoholic fermentation is batalytic, in sd far as the formation of alcohol and carbonic ^V;id is con- cerned ; but the analogous part of the process, — the multiplication of the yeast, — cannot be considered as a catalytic action, for a direct affinity chemical or vital, exists between the yeast and the gluten of the wort. With regard to the morbid poisons, it cannot be shown that they in- duce any new combinations in the blood into which they do not them- selves enter, for the ohly appreciable changes which are produced, are the removal of the material which gives the susceptibility to the action of the morbific matter, and the increase of the morbid material itself, both efiects evidently depending on an affinity exercised between the latter and the specific ingredient of the blood, thtis placing the action Without the pale of catalysis. Another theory which has been cousidered by many as bfeing liable to fewer objections than any other hitherto proposed, is the parasite theory. This theory was first suggested by Kircher, and Mi since been warmly fedvocated by Dr; Holland and Prof. Henle. Prof. Henle atgues in support of this theory. Firstly, That no sub- stance other than an organic one is known to increase by the assimila- tion of foreign materials. Secondly, The effect produced by the morbid poisons bears no ratio ib the quantity of the substance introduced, which circumstance mu&t fevidently depend upon the prolific power of the latter, therefore, accord- ing to the foregoing argument, this substance is probably organic. !n unnbticed, it has vague and obscure, investigations would Simon throws out a la of these diseases, eris. Certainly they vhy the phenomena ve why they should lOgue arfiong ordin- l from this assump- jf actions styled ca- in this class, they the morbid poisons it 6annot be cataly- the agent which )mbination resulting olic fermentation is arbonic ^cid is con- multiplication of the for a direct affinity jluten of the wort. loWn that they in- they do not them- 1 are produced, are ibility to the action )rbid material itself, jrcised between the placing the action ly as being liable to the parasite theory, since been warmly irstly, That no sub- se by the assiihila- ons bears no ratio circumstance must r, therefore, accord- bly organic. Again, The periodic nature of many of these diseases shows a close analogy with what occurs in the developement of organic substances. The definite period of what has beeji called incubation, and the iime which elapses between the commencement of the fever and the break- ing out of the eruption, are very similar to what occurs during the pro- ■ gressive developement of organisms. ' The same means, also, which favor, limit, or prevent the formation or • developement of organic substances, also favor, limit, or prevent the ac- tion of infectious matter, as heat and moisture, which are favorable to botl) ; and acetic acid, which acts as a poison to organisms, and whose influence in checking contagion is well known. Moreover, organic sub- stances, as infusoria, and parasitic vegetables, may, like contagious 'matter, remain dry for years without losing the activity. In addition to these general arguments tending to prove the organic nature of the morbid poisons, Henle endeavors to support the theory istill further, by referring to several diseases found among the lower or- ders of animals, and especially to one, eminently contagious and of a pa- lasitic nature, existing among silkworms. lie attaches great importance to this disease, (muscardine,) evidently considering the analogy to be Jperfect. If the contagious nature of the disease be alone considered, the taialogy is certainly complete ; but the resemblance does not extend to other equally important characters of the zymotic diseases, for, as shown by Simon, this disease, together with other diseases commonly known to be parasitic, such as scabies, the various kinds of porrigo, hydatids, &c., are of all diseases the most essentially local, proving injurious only in one of two ways; 1. Locally, from pressure or irritation. 2. (rene- lally, from the local irritation becoming inflammatory, or by the system becoming animated. This is especially true of muscardine, to which Benle attaches so much importance. The disease is purely a local one, extending from the point of inoculation until it involves the whole body, Uid proving fatal only as the extreme result of pressure or exhaustive drain. ' The course of most of the true zymotic diseases differs widely from this. In them the local symptoms are generally trivial when compared lirith the constitutional affection; indeed, in the severest forms, as in cholera, plague, &;c., the disease often proves fatal before the local symp- toms have begun to show themselves. This theory, then, in its present form, cannot be considered as sufficient to explain the phenomena of the zymotic diseases ; for none of the ex- amples cited are so closely allied to them as to admit of our inferring a iimilarity of cause. It is true, that of late years animalcules have been ieen among the products of one or two diseases, sometimes included un- V ! 10 der the same head, such as goiiorrha?a, glanders, Jtc, but these diseases are so different in most of their characters Irom the true zymotic type, that the propriety of admitting them into the same class may well be questioned. But though the arguments brought forward in support of this theory, have failed to prove that the active principle of the morbid poisons con- sists of parasites or animalcules, according to the common acceptation of these terms, yet they go far towards proving that it is organic ; so that, instead of condemning the theory as altogether erroneous, we should ra- ther attempt to modify or remodel it, in such a way as to obviate the dif- Jfxculties which hitherto have opposed its adoption. The animalcules or organisms found in the products of parasitic dis- eases, seem to me to be too highly organized, or of too large a size, to admit of their existing in the blood ana circulating with that fluid. They have been found in various extra-vascular situations, as between the fasciculai of muscular fibre, in the mucous and cutaneous follicles, &c., but I am not aware that any such have been found within the vessels. But organisms may, and do exist in the blood. Modern physiology has shewn us, that nearly every function of the body is performed through the instrumentality of cells ; indeed, so numerous are they, that X\ie whole body might almost be considered as an aggregation of them. These cells are possessed of vitality, at least they are subject to its ordi- nary laws. They have a period of progressive development, a period of maturity, and one of decadence, and they perform vital functions, as those of nutrition and secretion. In the healthy ^^late, the blood is loaded with these organisms in the shape of corpuscles, which, in countless my- riads roll on with its ceaseless current. But it is not in the healthy condition alone that living cells exist iu the blood. Pathology has also pointed out to us more than one disease, whose proximate cause consists of the development and multiplication of cells within the blood. Take for example, Pytcmia. A vein inflames and suppurates. A circumscribed abscess is formed which contains pus. This pus, so long as it is sejiarated from the circulating blood by the fibrinous barriers, pfoduces only local results. It probably goes on increasing at the ex- pense of the superimposed textures, untii it reaches the surface and is expelled, scarcely any constitutional effect being produced. But sup- pose the abscess does not reach the surface. The dykes are broken down, and the pus cells make their way into the circulation along with the blood corpuscles ! What then is the result ? Do they act as simple foreign bodies, suffering themselves to be quietly extruded from the sys- tem, or at rnost, giving rise to small and circumscribed abscesses in some 11 ut these diseases ue zymotic type, ass may well be rt of this theory, orbid poisons con- non acceptation of organic ; so that, r •oiis, we should ra- 1 to obviate the diC- ;ts of parasitic dis- too large a size, to g with that fluid, itions, as between ineous follicles, &c., i'ithin the vessels. Modern physiology body is performed icrous are they, that fTTregation of them. Jc" subject to its ordi- 3lopment, a period of •m vital functions, as 3, the blood is loaded ich, in countless my- living cells exist in )re than one disease, nt and multiplication PS and suppurates. A as. This pus, so long the fibrinous barriers, increasing at the ex- ihes the surface and is r produced. But sup- rhe dykes are broken circulation along witli Do they act as simple extruded from the sys- ;ribed abscesses in some of the organs ? On the contrary. The disease from being purely local and of little moment, at once becomes constitutional and most intense ; • a fire is instantly lighted up which soon spreads over the whole system. The pus corpuscles are reproduced in immense numbers, infiltrating the internal organs or forming large purulent depots externally. The pus here comports itself in a manner very similar to the morbid poisons, J) producing immense results fjom a very trifling cause. ^> Another example of the presence of morbific cells within the circu- lation, may be found in secondary cancer. These secondary formations are produced by the iirrcst, in some organ or tissue, of cartcer cells or their gt^rms, derived from a primary cancerous growth, and circulating 'With the blood. The prolific nature of the cancer cells, explains the ra- ■ pidity with which whole orguns become converted into a cancerous mass. Primary cancer, like a common abscess, is purely a local disease so long as it remains primary, producing only local results, and in most in- stances curable by local means. But if in any way the cancer cells or their nuclei, like the pus-corpuscles in pyemia, find their way into the blood, then again, an intense constitutional disease is lighted up, the products ot which, as in the foregoing case, are identical in character with the primary matter introduced into the blood. Cancer has boon all but proved to be transmissible from one individual to another. Laugenbcck produced cauccious growths in the lungs of a dog, by injecting cancerous r.atter into the veins. The diseaSvj, how- ever, is far from being contagious to the same extent as most diseases commonly known as contagious ; but this is easily understood, if we bear in mind the comparatively large size of the cancer cells and their nu- clei, which precludes their entrance into the circulation under ordiriary circumstances, or their dissemination in the atmosphere, like the poison of infectious diseases. Here, then, are two diseases in which cells figure as the active ttid essential cause, ]iroving not only that morbid cells may exist within the circulation, but that they may there reproduce themselves, acting in a manner very similar to some of the morbid poisons, and in one of the diseases at least, (if the contagious nature of cancer be admitted.) giving rise to a remarkable property, common to all the zymotic diseases, namely, the capability of being transmitted from one person to another. These diseases constitute another link in the chain of evidence sup- porting the organic nature of the morbid poisons, while at the same time .they lead us towards the conclusion, tliat as in the Ibrmcr, so in the latter, T^lls constitute the active principle. Another argument in favor of the orjiniirc nature of (lie morbitl poisons, \r i -a ( I i I W' 12 (and which 1 have purposely kept back until after tlie coiisidcniticn oi cancer,) may, I think, bo drawn irom the action oi some of that class of remedies commonly known as alteratives. Let us take a common example. Arsenic has been Ibnnd useliil both locally and constitutionally in the trentmont of cancer ; in iiict, it is al' most the on'y sulistance which can be said to possess any p(jwer what- ever over this disease. It has also been used, it is said, with ffreat success in cases oi poisoned wounds I'roni the bites ol serpents. In inter- mittent lovers, and in other periodic diseases, it has often proved suc- cessful after all other curative means have lulled. There are some other diseases not very closely allied to zymotic diseases, but which have many characters analogous to them, in which arsenic forms almost tlit- sole remedy : such are some of the S(iuanui', as lepra, psoriasis, tVc. As an external application, arsenic lias bi-en ibund preferable to more powerful caustics in cancer, and in sueli diseases as lupus, and an ointment of it has been Ibund almost a speeilic in onychia maligna. 13ut arsenic is not the only one of the class which possesses this extensive range of speeilic actions. jMuny others possess similar powers. The curative power of mercury is well known in at least one contagious disease. It has also been found to possess great power in checking the p-ogrcss of cholera, and its use in many lurms ol" fever is well known. Many chronic skin diseases have yiekled to it, when all other remedies have fulled. Local applications of it ulso, in the form ot corrosive sublimate, have been found very useful in some forms of porrigo. Nitrate ofsilver is another of tills class, so Is iodide of potassium, and I might go on enumerating others, all of them possessing the same qua- lities ; let these, however, suHiec for our ])urpo.se. Now, how lire these actions to be explained ? 1 am not aware of any satisfactory or definite exphuiation having ever been given. These re- medies are said to exert a peculiar influence on the system, by which its morbid functions arc corrected, Arc. iVc. ; but the nature of that influence lias not been satisfactorily explained. Jt will be observed that those yubstances' which I have mentioned, and many otliers belonging to the sfjune class, possess properties highly destructive to life in all i?s fbrrns. Now, may not thc;jr alterative action depend upon this proj)erty? S^ome of the diseases in which their bene- liclal inliuence is exhibited, have an organic cause, such as cancer, por- rigo, iVc, and in most of the others there are strong reasons for inferring ihc cause to beef a slmlkir natiire. The well known beuelielal effect of mercury in common inflammation, might be explained in this way. Jiiliammation is a disease commonly coauccted with iiicreti'-.ed vitality ol the t^yistem. In thoac persons pc;;- :oiisiil«'ruticin oi oi that clus» of )unfl uscrul botli in liict, it is al- ly |«jwer what- saiil, with preat rpents. In inlcr- ften proved Suc- re arc some other hut which have lornis almost tin- psoriasis, tVc. As rclerublc to more is, nnl an ointment trna. But arscnir xtcnsive range ol" rs. The curative igious disease. It 115 the p"0!;rcss ox n\-u. Many chronic cdies havt! lulled. Ldilinvate, have been ; of potassium, and isiug the same qua- im not aware of any n given. These re- system, by which its lure of that influence I have mentioned, ?ss properties highly livriir alterative action in which their bene- such as cancer, per- I reasons for inlisrring Duimon inflammation, a disease commonly 111 thoac persons pci- '«>■ f- sesscd of the inflammatory diathesis, the blood corpuscles exist m largo proi)ortion, and all the functions of the body arc carried on with unusual activity. May not the mercury, then, act beucflcially by reducing this superabundance as it were, of vitality, by virtue of its speciflc power; possible by retarding or preventing the growth of the blood corpuscles ; while bloodletting produces the same efli-ctby directly withdrawing from the system a portion of its vitality, represented 1)y the amount of the vital fluid abstracted 1 This view will be still further strengthened if we consider the injurious effects of mercury in strimious or cachectic habits, where the vitality of the system is already low, and Avhcre the depres- sing clTect'i of the medicine must of necessity jjrove deleterious. There are other substances, such as cod-liver oil, sarsaparilla, &;c., com- monly classed among the alteratives, and which cannot be said to possess these destructive powers; but the impropriety of placing these substan- ces in the same class with the others, seems sufliciently manifest, for their beneficial effects are much more easily and satisfactorily explained, by ascribing them to their tonic and dietetic qualities, than to any specific power which they can be supposed to possess. Tilt! eunelusions to be urawn from the action of alterative medicines may be stated briefly as follows. 1st, That most substances properly included in this class possess properties unfavorable to the developement, and destructive to the life of organisms in general. 2d, The beneficial operation of these substances is manifested in diseases known to depend ou the developement of organisms, as in cancer, porrigo, scabies, &;c. 3d, That their beneficial action is also often seen in diseases known to de- pend on the action of morbid poisons, as in syphilis, cholera, fevers, Sec. 4th, Their beneficial action in tliese cases will be best explained by sup- posing the proximate cause of such diseases to be organic. To sum uj), then, how stands the case 1 The action of alteratives adds another item to a mass of evidence almost incontrovertible in favor of the organic nature of the morbid poisons. The only question which yet remains to be definitely settled seems to be, the precise gmde or class to which the organisms belong. I have stated my reasons for believing' that they cannot belong to any class commonly understood by such names as parasite, animalcule, msect, &;c., and I have alsjo given reason» for supposing them to belong to the class of organisms known as cells. Whether these reasons will be as satisfactory tc other minds as they now are to my own, remains to be seen. It is true, the cells which have been assumed as the agents in the zymotic diseases, have not as yet been physically demonstrated ; but may we not hope, and indeed predict, that accurate observation will yet enable us to identify the peculiar cell or germ of each disease, as unerringly as we can now identify those of can- cer er pus. 7 f* ^uMta "ii. I ■ .Til III mtiU mt^mur ,■ II u f I !! r. ': I! •I M 1' J f : Si i;l ^ III such an iiivesligation, our search is not tu be directed towards ob- jects so pulpublc lis tt pns-cori)Uscle or a cancer cell, but towards objects so luiniite as to be capable not only ol'dKiusion through the atmosphere, but of iincliug- their way into the blood, through membranes now consi- dered to bo j)erfe;^tly continuous. The disease which olleis the best jirospect of success in this examina- tion, would seem to be small pox, ur some disease abounding in material products, in which the contagious matter is unquestionably given off, mingled with the products of common inilainmation. The matter taken from a small pox pustule, tor instance, must contain ordinary pus, and, in addition, the specific contagious substance, whatever that may be. Now, the microscopic characters of pus being tolerably distinctive, its admixture with this foreign material must necessarily be supposed to al- ter its appearance, the only dilliculty being, that our present means of examination are not sufficiently refined to enable us to detect the diffe- rence ; but when these means shall have been rendered more efficient as science advances, we may, I think, reasonably expect such discoveries, ncr would they be so surprising as the original discovery of the pus or blood corpuscles themselves. IV. — We come noiv to cojisider hrirjhj the Indications for Treatment, sug- gested bji the fore goi)ig vicics. In the first place. By way of preventing the spread of these diseases, every effort should be made to destroy the infectious matter external to the body, in fomites, &c. ; and this will be best accomplished by the use of means or substances which have the power of destroying the vitality of the poison ; such as exposure to heat, cold, chlorine gas, solutions of chloride of zinc, arsenic, corrosive sublimate, &;c. &.c. Secondly. In view of the great predisposition to these iliseascs, en- gendered by the accumulation of effete matters in the blood, all circum- stances should as much as possible be avoided, which tend to produce such an accumulation, as fatigue, exposure to noxious exhalations, damp and low situations, crowded dwellings,