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The burning in the affected parts was most acute. The nailswere roughened. This patient was under treatment for twoperiods of five and nineteen months, and left only a littlebenefited. During this time she had severe neuralgia in thehead and extremities, and herpetic eruption in the course of ithe sacral and cutaneous nerves.—Case 4 : A dressmaker, Iaged thirty nine, had previously suffered from psoriasis.The present illness seemed to connect the latter with pityri-asis rubra. There was hypersemia and desquamation of thewhole surface of the body, with the exception of some partsof the face and between the scapulae. The scales werebranny, but on the extensor surfaces, especially about theknees, the scales were thicker and heaped up. The nailswere all dry, cracked, and discoloured, and the hair cameout. There was much burning of the skin everywhere,After three months’ treatment the pat’ent left, free from allroughness and scalines. A case was also attended to inwhich a patient with running eczema of the face and legshad a pityria-is-rubra-like condition of the back. Afterdrawing- attention to the characteristics of the di-ease,the chief being hyperæmia and desquamation of almostuniversal distribution, and showing (from Devergie’s descrip-tion, cases by Sparks and Duhring, and Case 3 of the series)that thickening and infiltrdtion, stated by most authoritiesto be absent, does in some cases occur, its course and treat-ment were briefly discussed. Its alliances were then dis-cussed, and it was pointed out that its resemblance andaffinities were with psoriasisandeczema, especially the former,from which it differed chiefly in the eruption being morediffused but less intense, in occurring later in life, and yield-ing less to arsenic. The author agreed with Tilbury Foxand Hutchinson in regarding the disease as a neurosis.Case 3 of the series was iustanced as particularly supportingthis view :-the linear extension of the disease (probably inthe course of nerves), numbness, and pallor of the fingerspreceding the eruption some months, and from the patienthaving severeneuralgic pains in the head and limbs, andnumb-nessin the later.—Dr. BROADBENT had known two case,; inwhich the disease had been mistaken for scarlet fever, hightemperature and albumen occurring in each cae.-Dr. R.CROCKER remarked on the transitional forms of the affection,some cases beginning as simple eczema. He mentionedsome cases under his care, and remarked on the tendencyto marasmus and death. He had found the urea excretion

to be small, but this might be explained by confine-ment in bed, &c. He could not associate any neuroticcondition.-Dr. B. W. RICHARDSON had seen but two

instances ; in one the eruption came on after great physicalor mental exhaustion. In spite of its symmetry he did notthink it was neurotic ; his patient suffered much from thecold.-Dr. MACKENZIE, in reply, adhered to the neurotichypothesis; in answer to Dr. Crisp he said the bloodhad not been examined.

EPIDEMIOLOGICAL SOCIETY.

THE fint meeting of the session was held at UniversityCollege, Gower-street, on Nov. 2ud, when the newly electedPresident, Dr. BUCHANAN, delivered the inaugural address,on Aids to Epidemiological Knowledge, of which the follow-ing is an abstract :-Our Society enters to-day on the thirty-first year of its

life. It has experienced its ordinary share of difficulties andits full measure of success. In no small degree its difficultieshave been the creators of its success. That greater concernis now felt ab ut scarlatina, typhus, small-pox, &c., than atthe time of the Society’s creation, and that public bodiesand their officers compete with us in their interest for theproblems which we study, is a result to which our Societyhas contributed iu a foremost degree, but we still continueto hold our place as pioneers. We have among us peoplewho study the subject from different standpoints-at thebedside, in the po-t mortem room, or in the camp, the ship,&c.; but, to be successful, we need to study the &dgr;&eegr;µos underother aspects than the technically medical—to study other&dgr;&eegr;µoi than our own, and to identify ourselves with states-men, geographers, and travellers - to obtain help from

chemistry and physics, from meteorology, botany, andzoology; indeed it would be difficult to name a departmentof hum m knowledge to which we do not hope some davto become indebted. The first idea is the place we shall

gratefully assign to mathematics. So identified is epidemio-logy with mathematics that there has occasionally been aconfusion in the popular mind, and the study of epidemicshas been regarded as essentially an affair of statistics.Epidemic disease claims the aid of numbers; but it wouldbe a serious error to think of this relation ending with arecord of quantity of disease, of death-rate, sickness-rate,&c. It is by arithmetical analysis of coincident circum.stances of one and another sort that a clue is often got aboutthe relation of effect to cause, as to efficiency of cause toproduce effect. The case of relation between cholera andelevation of soil is an example familiar to us of an experi-ence noted by the arithmetician to have something in it forthe physician to inquire about. Of another sort of arith.metical help an evidence was afforded to me in the investi-gation of a fever outbreak, when of two competing sets ofcircumstances either of which might contain the cause of theoutbreak. I was told the probabilities in favour of the oneset were as 375 to 1, while the probabilities in favour of theother set (putting aside any probabilities against it) werebut as 6 to 1. As another illustration : An investigation isbeing made as to the possible influence of an infectiouscentre upon its neighbourhood. Putting aside influences thatmay destroy it, there is necessarily more of it at a spot nearthe centre than there is at a spot further off-that is, solong as the distribution is effected after the fashion of asomething radiating from centre to circumference. Thequestion arises, How much more infection will there be at agiven nearer pint than at a given more distant point? Be-cause an answer to this question is wanted before we can goon to consider the meaning of the facts we observe. Inreply to this question we shall see that the distribution ofan infection will be effected according as it is effected alonga single plane or into space of three dimensions. In theformer case the relative amounts of infection present intwo given places will be inversely as the distance ofeach place from the centre. In the latter they will beinversely as the squares of the distances. Now, thereis reason for thinking the contagious matter is subjectto the laws of gravitation, wherefore it is to the planeof the earth’s surfa’e that the con’ag’on will tend,and its distribution in that plane will come to be effectedaccording to the law that governs radiation in one plane,In this way we can appreciate the rate at which the spreadof infection should manifest itself, and we can understandthe significance of the actually observed distribution. ThEbest example of our indebtedness to physical science may bEtaken from the lessons that the physicist has taught us o:the characters of infection itself. At the foundation of oulSociety there was but a half-formed recognition of the facthat every disease of the class with which we concern ourselves hM a material of its own. The earlier addresses oour first President contain many exhortations to the use othe microscope as a means of understanding the nature odiseases which we had to study; and from the microscopein the hands of Dr. Beale we soon came to know of theexistence of particulate matter as infective liquids, but iwas not until the resources of the physicist had been appliesto separate out the particle from the fluid that any conelusion could be formed about the inherence of the qualit:of contagiousness in the one or the other element of thinfectious liquid. The method of diffusion was used bChallveau to such liquids, and first to vacciae lymph; thsoluble was separated from the particulate, and the potenc.of the lymph was found to be in the particulate only. Iwas soon found that other contagia, like smalt-pox, exhibithe same qualitv. At, this time the pathologist had beecautiously tracking other lines of research, and so long agas 1841 a happy inspiration had led Dr. Farr to insist upothe use of the word " zymotic" as best expressing thcharacter common to epidemic, endemic, and contdgioudiseases, and then in 1848-9 Dr. John Snow had satisfiehimself that the best explanation of the phenomena (

cholera and its spread was to be found in the existencof a specific cholera " cell" capable of passing into othebodies and producing cholera in them. Further, D]Budd reached the judgment alike for diseases prop:gated through air and for those communicated by waterthat "the contag’ous agent which issues in the excreta ithe fruit of its own prior reproduction within the already irfected body." For years before the researches of Pasteur i1865 into the silkworm disease the suggestion that paticulate contagium must, almost of necessity, be contagiurvivum. had been one that had its attractions for the botanist

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What if it should be the reproductive matter of some vege-table thing? At one time it did seem that we should findthe genesis of cholera in that direction. It is to be admittedthat Dr. Sanderson’s critical examination of ProfessorHallier’s experiments relegated to the domain of the un-proved this promising vision, but we are coming more

and more to expect that the materials of some contagiahave another habitat, perhaps in a known but not yetrecognised alternative form. Unquestionably the prospectsheld out to the epidemiologist are of the most fascinat-ing kind. As there was a period when we were promisedin the behaviour of metallic oxides in the presence ofperoxide of hydrogen the line of explanation of whatconstituted contagiousness, so now we seem to have reacheda point where the botanist offers us the most promisinginsight into the nature of what is epidemic. I wish toshow the line that remains to me by pointing out some ofthe interesting and important consequences that followfrom the doctrine which would regard the material ofinfectious disease as something in its essence having a placeand mode of life beyond the infected body. One of these isthe possibility that is appearing of being able to cultivatethat material outside the body in ways that shall give itdifferent degrees of potency. So long ago as 1867 Dr.’Sanderson had distinguished two sets of consequences pro-ducible by local inflammations artificially set up in thelower animals. The oue a chronic disease having thecharacters of tubercle, the other an acute disease presentingthe features of pysemia, and both infective, and being pro-ducible at the will of the experimenter by the inoculation ofthe same material. In 1872 he demonstrated in a numberof acute infective processes, microzymes abounding in theexudation liquids and in the blood; he had shown how bysuccessive transmissions of infective material an intenselyvirulent material could be obtained, the original pro-duct and the cultivated material having certain micro-scopical and physical characters distinguishing the one

from the other. Dr. Koch of Walstein made a notableadvance, and found the bacilli of splenic fever growand multiply in blood serum or aqueous humour, and evenin artificially prepared cultivating liquids, and that thiscould be done through successive generations. More thanthis, he found that mice inoculated with matter that containednumerous spores died of splenic fever in twenty-four hours,whereas mice inoculated with liquid in which spores werescarce did not die until later. And shortly afterwards ourown Dr. Klein found this same property of cultivability out-side the body in the very similar bacilli of the disease of thepig known as pneumo-enteritis, and liquid of the eighthgeneration inoculated in a pig produced a disease reduced inintensity. In 1879 Dr. Sanderson found that the cultivationof anthrax in the body of rodents modified the poison, sothat the subsequent inoculation of a bovine animal did notdestroy the life of the latter, but protected it from subse-quent attacks of disease. At the same time M. Pasteurmade out for the disease called fowl cholera the same qualityof cultiva’)itity by multiplication of its bacilli in inorganic,but not vitalised, liquids. We cannot help having before usthe dazzling prospect of being able to offer to men andanimals the protection of a trivial disease against each morefatal disease, to achieve what M. Pasteur calls the vac-cination of animals against the several contagia. Butperhaps as valuable are the indications we are gainingof possible means of preventing epidemic disease in otherways. Suggestions arise of material of contagion having,like tapeworms, an alternative mode of life outside theanimal body, or in one animal body leading a different sortof existence from that in another animal body. What ifthe material of cholera, or of yellow fever, or of entericfever, should have another habitat than as a contagium,and there exist, having no power of producing disease untilits conditions were changed, but then altering its mode oflife, and becoming the active material of disease in animalsinto whose bodies it was introduced? What if we couldrecognise it in its other fashion of life, and destroy it, orprevent the conditions necessary for its development? In1875 Dr. Klein recognised in a particle peculiar to entericfever a microphyte which had been identified by Professor’Cohn of Breslau, as occurring in the water of a well atBreslau, and the district of the city supplied by that wellhad long been notorious for the amount of enteric fever in it.The relation between milk and outbreaks of enteric, or

scarlet fever, or diphtheria, has been thought of as a mereaffair of disease entering milk-cans bv the aid of water used

in washing, or of hands used in milking cows. It mayturn out the disease-producing milk has received some

organism that under other conditions of life would havebeen impotent, or such organism may have been derivedfrom the body of the cow herself. Indeed, the hygienistis coming to suspect that he may often have to do withorganised material not far developed from perfectly non-specific geims. It is impossible not to recollect the inquiriesof Dr. Ballard at Welbeck and Nottingham, in which heheard of strange maladies occurring in groups of people, andhaving their cause in some common article of food. Suchare a few examples of the aid which pathology is renderingto an understanding of epidemics.

Dr. Buchanan’s address was followed by a paper on " TheProgress of Zymotic Micro-pathology," by Dr. G. C.HENDERSON. After alluding to the great importance whichthe question of the relation of micro-organisms to diseasehad recently assumed, the speaker enumerated the variousaffections in which their occurrence had been noticed. Hethen gave a brief summary of the researches of Pollender,Brauell, Davaine, Klebs, Sanderson, Cohn, Koch, Green-field, Pasteur, and Toussaint in anthrax or splenic fever,showing how gradually our knowledge of the life-history ofthe bacillus anthracis was obtained. Special reference wasmade to the "protective inoculation " of modified virus asrecommended by Pasteur and Toussaint in France, and bySanderson and Greenfield in this country, as well as thecriticisms on the method recently published by Koch. Theprocess adopted by the latter for "pure cultivation," to pre-vent the unchecked mixture of the original bacillus,micrococcus, &c., stock with accidentally introduced aerialgerms, was to grow them on media rendered semi-solid bygetantine, instead of in liquids. Gaffia,y’s experiments onthe cultivation of aspergillus and other "moulds" by thismethod were referred to as tending to show that Grawitz’sresults on the development of "moulds," ordinarily harm-less, into toxic products were due to contamination of thefluids used. In septicaemia the researches of Billroth,Klebs, Rindfleisch, Lister, and others were noticed, as wellas the recent observations of Semmer and Krajewskion the protective inoculation of a modified virus inthat group of affections. Bacilli, bacteria, and micro-cocci were also mentioned as the supposed causes oferysipelas, diphtheria, variola, vaccinia, enteric fever, mala-rial fevers, leprosy, scarlatina, and several other complaints ;while the researches of Obermeier, Carter, Heydenreich, andothers on the occurrence and the connexion between re-

lapsing fever and the spirillum in the blood were alluded to.In conclusion, the author expressed his opinion that thereasons for admitting the micro-organisms to be the causes ofthe diseases in anthrax, pneumo-enteritis, fowl cholera, andsome forms of septicaemia, were as strong as those for hold-ing the trichina spiralis to be the cause of trichinosis. Inthe other affections, when the malady was communicable byinoculation from one person or animal to another, and thesame organism was present in the blood or tissues of both,he was, while inclined to admit the organisms as causes ofdisease, obliged to look upon the case as not absolutelysettled till cultivation and inoculation experiments had beenmade. The author felt obliged to refrain from a full accept-ance of Pasteur’s result till the question of the non-recurrenceof anthrax after one attack was definitely proved. In the dis-cussion which followed, Sir Joseph Fayrer, Sir William Smart,Dr. Cobbold, Dr. Vandyke Carter, and others took part.

CAMBRIDGE MEDICAL SOCIETY

THE first meeting of the Society, since the summer reess,was held on Friday, October 7th, at 2.30 P.M., PiofessorPaget, M.D., F.R.S., President, in the chair. A letter wasread by the President, from Dr. Creighton, announcing hisresignation of the office of Secretary, owing to his leavingCambridge. A resolution was passed unanimously, thank-ing Dr. Creighton for his past services to the Society, bothas secretary and treasurer, and the President undertook toconvey to Dr. Creighton the expression of the feeling ofthose present. Dr. Bacon and Mr. Shann were appointed asjoint hon. secretaries, the former accepting also the functionsof treasurer. fDr. ANNINGSON read a paper on the Etiology of Zymotic

Diarrhoea. He showed, from his experience as medical