TUBERCULOSIS AS AN INFECTIOUS DISEASE-

WM. T, COUNCILMAN, M. D.

(Read befort the Clinical Society of Maryland , CVA 20M, 1882.)

[REPRINT FROM THE MARYLAND MEDICAL JOURNAL OF NOVEMBER IST. 1882].

Villemin, a French investigator, in1865 first demonstrated by inocula-tions on rabbits and Guinea pigs, thattuberculosis is an infectious disease,capable of transmission from one ani-mal to another. He introduced bothgrey miliary tubercles and cheesypneumonic substance under the skinof the animals and found, after aninterval of from ten to twenty days,tubercles in the lungs, and after a stilllonger period in the intestines andmesenteric glands. So striking a re-sult led to frequent repetitions of theseexperiments, and the literature of the60th years is full of the subject. Theresults ofthese first experiments werevarious; in general, however, the the-ory of Villemin encountered on allsides much opposition, both fromGerman pathologists and from BurdonSanderson and Fox in England. Theidea came to be held that the tuberclewas the result of the absorption of athickened inflammatory exudation,and those animals, such as rabbits andGuinea pigs, in whom purulent exuda-

tions were prone to become inspissa-ted, were most subject to tuberculo-sis. One of the strongest defendersof this view was Cohnheim, who, oncarrying out together with Frankel,Villemin’s experiments in the Pathol-ogical Institute in Berlin, found thatafter the introduction of any foreignbody, either a piece of paper or ofcork into the abdominal cavity of rab-bits and Guinea pigs, they alwaysdied of tuberculosis. Waldenbergheld the view that tuberculosis couldbe caused by any finely dividedsubstance being taken up by theblood.

Villemin was also not without hisadherents. Especially from the ex-periments of Klebs it seemed that in-oculation with various inflammatoryproducts could produce foci of inflam-mation, but that true tuberculosis wasonly produced when tubercular matterwas inoculated. Cohnheim andFrankel,on repeating their experimentsseparately, the former in the BreslauLaboratory and the latter in his Ber-

lin dwelling, were not able to obtaintheir former results and were led fromthis to believe that the animal stalls inthe Berlin Institute were thoroughlyinfected with the tubercular virus, andthat the infection of the animals tookplace accidentally. Experiments weremade with feeding. Aufrecht, Gerlachand others found that on feeding ani-mals with tubercular matter tubercul-osis was the result. Gerlach fed sev-eral animals with the milk of a cowthat was tubercular; with one excep-tion they all became infected. Tap-peiner, and later Weichselbaum, pro-duced tuberculosis in dogs by causingthem to inhale dried tubercular sputa.

These experiments could not at allbe reconciled with the theory of theabsorption of an exudation, and thequestion seemed finally to be settledby the experiments of Cohnheim andSalomonson. In order to attaincertainty in the matter they adoptedthe plan of introducing a small pieceof caseous matter into the anteriorchamber of a rabbit’s eye. Here theexperiment was thoroughly undertheir control, and any changes takingplace in the tissues could be watchedfrom day to day. When the matterinoculated was carefully cleaned itoccasioned only a slight iritis at thetime, which was easily controlled byatropia; the chamber remained clearand the small piece of matter could beseen attached to the iris where it re-mained unchanged for a period oftwenty to twenty-five days. Afterthis lapse of time small greyish nod-ules developed in the iris, a severeiritis was set up and the eye was lostthrough panophthalmitis. Generalinfection, and a more or less severetuberculosis ofthelungs,lymph glands,etc., sometimes followed, but not inevery instance. By these experimentsnot only the question of the inocula-bility of tuberculosis was settled, butwhat was of especial importance, itwas seen that there was a definiteperiod of incubation and that the tu-

bercles were developed primarily andwithout an intervening inflammation.

Let us now see how the matterstood with regard to human tubercul-osis. Here the old doctrine regard-ing it as due to the absorption of theproducts of a previous inflammationplayed a great role. Buhl, whom wehave to thank for so much that isgood in the literature of the subject,was one of the first to call attentionto the presence of a caseous focussomewhere in the body in nearly allcases of acute tuberculosis and re-garded the latter as an infectious dis-ease, or more properly speaking, adisease arising from a self-infection ofthe organism. For him the caseousmaterial when once formed, no matterwhether it be a caseous pneumonia orcaseous lymph gland, was in itselfinfectious and capable on its absorp-tion of infecting the organism with aspecific disease. Taking this view ofthe matter, in the light of presentideas regarding infectious diseases,viz., that they are produced by apathological agent capable of increaseentering thebody, there increasing andproducing as a result of its presencecertain specific alterations, and whentransferred to another body affectingit in a similar manner, we are forcedto the conclusion that the humanbody is in itself capable of producingsuch an agent, an idea which standsopposed to all our knowledge of theprocesses of life. The investigationsofSchiippel on the so-called scrofulouslymph glands have shed much lighton the matter. He always finds inthese indurated caseous glands truemiliary tubercles, and we are forcedto the assumption that the same agentwhich led to the formation of tuber-cles here, led on its absorption to theformation of tubercles elsewhere.

When we follow the advance of tu-berculosis from point to point in thebody much light is thrown on its in-fectious nature. It is always a directspread of the virus from one place to

another along certain definite paths.Take the most ordinary cases of tu-berculosis we meet with—theadvanceddisease in the lungs coupled withulcers in the larynx and ileum and amiliary tuberculosis of the liver andgenerally also of the spleen. Howplain is here the course of the infec-tion. The virus is taken into thelungs through the inspired air, andthere the primary tubercular focus isestablished. From this the diseaseadvances in the lungs, both by con-tinuity and by independent infectionof other parts of the same or of theother lung by aspiration of the sputathrough the bronchi. From the l ungsthe virus is taken up by the lymphatics,the bronchial glands become caseousand usually the infection spreads nofurther in this direction. From thethorax comes the infect'on of thelarynx, where we usually find the tu-bercular ulcers on the posterior larynxwall, at the spot where the sputa isapt to lie longest before being ex-pectorated. A quantity of the sputais always swallowed, and we have theinfection of the intestinal track asshown by the ulcers in the ilium.Why the infection most generallytakes place in the ilium is not accu-rately known; it may be that , thesecretions in the other parts of thedigestive canal interfere with theaction of the virus, or it may be thatthe lymphatic tissue here offersleast resistance to the attack. Ulcer-ations in other parts of the digestivecanal are by no means uncommon;only the oesophagus seems to enjoyimmunity, though even here there aretwo or threecases reported of tubercu-lar ulceration. From the ulcers in theilium the disease spreads in two ways,by the lymphatics and the portalvessels; through the first we have atuberculosis of the mesenteric glands,through the second a miliary tuber-culosis of the liver where we generallyfind the tubercles either in the inter-lobular spaces or in the periphery of

the lobules. The liver acts here as afilter, retains the virus in itselfand soprevents a general infection of thesystem; miliary tuberculosis of theliver seems to have no injurious effecton the general organism and alwaysruns its course without symptoms.

The disease on the other hand, maybegin first by an infection of the in-testinal canal, and then attack grad-ually the mesenteric glands, the peri-toneum, and in females the Fallopiantubes and the uterus. Our knowledgewith regard to the infection of thewhole organism with acute miliarytuberculosis as a result, has been muchadded to by the labors of Weigert andPonfick. As the result of their in-vestigations, we can say almost withan absolute degree of certainty, thatin these cases we shall find a tuber-culosis of the veins or of the thoracicduct. In one of these two ways thevirus gets into the general circulation,and when there in sufficient quantityno organ in the body is free from itsattack. Organs which are said toenjoy almost an immunity from miliarytubercle, such as the bones, the ovariesand some others, only enjoy this im-munity because they are not examinedwith sufficient care. In three of thecases of miliary tuberculosis, I haveseen, it was possible to trace the infec-tion in this way; in one there was alarge tubercular nodule in one of thepulmonary veins, in another in one ofthe splenic veins and in the third acaseous mass filled up the thoracicduct. That we are not able to tracedefinitely in such a way the source ofall cases of acute miliary tuberculosisis true, but it can hardly be ex-pected of a pathologist that he ex-amine makro- and mikroskopicallyall the veins of the body. In somecases we have the infection of onlya few organs through the generalcirculation, for instance besides theordinary changes, a tubercular focusin the kindeys or in the brain. Insuch cases one must suppose that but

4

little of the virus got into the generalcirculation and was arrested here. Ina few cases the epididymis or testicleand the pia mater are primarily at-tacked; how infection takes place inthese cases we are at present unableto fully explain. For the testicle orepididymis Cohnheim suggests an in-fection through the act of coitus. It istrue we do have tubercular affections(ulcerations) in the vagina and cervix,but when these affections exist inwoman she is usually placed out ofthe pale of sexual pleasures. Thepossibility of this source of infectioncannot be excluded, but it seems tome a very remote one. With regardto primary tubercular meningitis thesubject is no clearer. Here the pos-sibility has been suggested of thevirus reaching the meninges throughthe upper nares and along the lym-phatics of the olfactory nerves. Weigertasserts that in cerebro-spinal menin-gitis the infection takes this course,and we have generally suppuration ofthe ethmoid cells, but there are nocases on record where tubercular af-fections of this part have preceded atubercular meningitis. Many pathol-ogists, however, deny the existence ofa primary tubercular meningitis; Prof.Chiari told me that in all his experi-ence he had never seen a case. Anumber of clinical cases have been re-ported of primary tubercular ulcera-tion of the larynx; these cases arerare; when, however, they do occurinfection can proceed from here to thelungs and digestive tract.

For the past three years tubercu-losis has been com/dered by most aninfectious disease, and the pathogenicagent in the case of miltzbrand andother diseases having been discovered,active search began to be made for abacterium here. Klebs, who aboveall others, possessed the happy facultyof finding germs wherever he soughtthem, was early in the field, and des-cribed an actively moving “monas tu-berculosis;” Schuller and Aufrecht

soon followed, the latter describingtwo forms, one of which he regardedas the cause of tuberculosis and theother of phthisis. These discoveries,although causing some stir at first,were soon forgotten. They were notsubstantiated by other competent ob-servers, Klebs, particularly, by hismany publications over all manner ofgerms, publications which for themost part have never been substan-tiated, acquired the distrust of theprofession, and his monas tuberculo-sis shared the same fate as his syphilisgerm. This matter has been finallyset at rest by a publication of Koch,in Berlin, over the aetiology of tuber-culosis. His investigations here, asin all his preceding labors, were dis-tinguished by so much care and ex-actness that his results, confirmed asthey have been by subsequent observ-ers, leave no room for doubt on thesubject. Scarcely any publication inmedicine has excited more generallythe attention of the medical world; thepaper has been translated and read inall tongues, and for me to give a de-tailed account of his work would besuperfluous. Sufficient to say hefinds a certain organism present in alltubercular processes, an organismdefinite in character, as shown not somuch by its morphology as by itsmanner of growth. This organism hehas isolated, has grown it just as thefarmer grows his wheat; when onesowing comes to maturity he plantsfrom this sowing another field (thefield being represented by a test-tubefilled with coagulated blood serum)and this replanting has been done insome experiments twelve times. Nowhaving a number of animals living inthe same habitation, eating the samefood and being all under exactly thesame conditions of life, he inoculatesa certain number of them with theproduct of the last sowing. These be-come sick and die of tuberculosis; inthe tubercular products are found or-ganisms in all respects identical with

5

those he first started with. This hehas done over and over again andalways with the same result. This, Isay, is proof, direct, positive, objectiveproof, that the organism is the causeof the disease; proof as positive asthat the field of wheat is the result ofthe seed sown. Not only has he setat rest the question of the infectiousnature of tuberculosis, but what wasof especial importance, he has shownus under what conditions these germsgrow, has shown us that they aretrue parasites growing only in theanimal body, and that they usuallyescape from the body by means of thesputa. Since Koch’s paper appearednumerous publications over the bacil-lus tuberculosis have followed, and inGermany all confirm fully the fact thatthis organism is always associatedwith tuberculosis, appearing both inthe sputa and in the tubercles. Stern-berg, in an article over the subjectpublished in the Medical Nezvs, quotesan English author, Burney Yeo, whosaid he had never been able to findthese forms, and Sternberg says thathe himself has often missed them inthe sputa. While working in theprosectorium of the Rudolf Hospitalin Vienna, through the kindness ofProf. Chiari, and the director of thehospital, Prof. Boehm, I had ampleopportunity of verifying Koch’s work,both as to sputa and tissues. I ex-amined from one ward in the hospital,with regard to the presence or absenceof bacilli, thirty specimens of sputa,which were sent down to me simplywith the bed numbers on the vessels.The specimens were from patientssuffering from all forms of lung affec-tion mostly tuberculosis. In threecases my report did not agree withthe clinical diagnosis; the first of thesewas a case diagnosed as chronic bron-chitis occuring in a young man oftwenty-five who had rapidly lost fleshin the past five months. The sputacontained bacilli in large number.In the other two cases diagnosed as

tuberculosis I did not find them. Oneof these two cases afterwards died,and the only thing (in his body point-ing to tuberculosis) were a few caseousand calcareous nodules in his lungsand calcified bronchial glands; whathad led the clinician (an extremelycareful and exact man) to make thediagnosis was the presence of bron-chiectatic cavities in the right lung,A friend of mine, an army physicianin Vienna, who has charge of a largemilitary hospital there, told me hehad found the bacillus in the sputa inabout 95 per cent, of his tubercularpatients, and in two cases had beenable to differentiate between typhoidfever and acute miliary tuberculosisby their presence. Up to the presentI know of no cases in which the urinehas been examined for them in tuber-culosis of the genito-urinary system,nor do I think the feces have beeninvestigated in cases where the iliumcontains ulcers. In all probabilitythey will be found in both these cases.The number found in the sputa isvery variable; sometimes the fieldwill be covered with them, sometimesnot more than three or four will befound on a whole cover slip. Thedifficulties attending their recognitionwhen so few are present, no doubtwill account for the fact that somehave had bad results in finding them.So far as my experience enables me tojudge, their quantity in the sputastands in no exact ratio to the extentof the disease in the lung.

One of the arguments most gen-erally used against the infectioustheory of tuberculosis is the fact thattuberculosis is essentially an inheriteddisease. Now the actual inheritanceof tuberculosis is very questionable;some few cases have been reported ofchildren being born with tuberculosis,but such cases are extremely rare.Even assuming this direct inheritanceto be a fact does that in itself speakagainst infection? Few will deny thatsyphilis is an infectious disease, and

6

certainly we have inheritance here.Tuberculosis is connected with in-heritance; to deny this would be todeny what is deeply rooted in thebelief of all men, both the professionand the laity. Some of the Germanpathologists deny that inheritance hasanything to do with the matter, andsay that it is only seemingly so be-cause a better opportunity is given forinfection when one member of a fam-ily is tubercular. But this cannotexplain it; there are too many casesknown in which the children of afamily all separated before any ofthem were affected and then livingapart from one another in different partsof the country have all died of tuber-culosis. To explain this we can onlyassume that some men are especiallypredisposed to tuberculosis, that theirtissues are wanting in physiologicalresistance towards this particularvirus, and that this it is that is inheri-ted, There is no fact in medicinebetter established than that men dif-fer in their susceptibility towardsvarious diseases, and not only do in-dividuals differ but families. Theremay be some difference,either chemi-cal or other, in their tissues, a differ-ence so subtle that we have no meansof determining it, which may raise orlower the physiological resistance ofthe tissues towards certain diseases;this certainly in the case of tubercul-osis is inherited. We must remem-ber that the farmer must have two

factors to produce a crop, not onlythe seed to sow but the ground mustbe prepared to receive that seed.

Now, gentlemen, one word more.I have heard so often the questionasked, what, after all, is the good ofthis discovery of Koch’s, that I feelnow is a good opportunity to answerit. Such questions will always beasked; in all probability when Harveydiscovered the circulation of the bloodmany practical people doubted thatany practical good could be derivedfrom it. But I can answer. Realpractical good comes from Koch’spaper. One thing, it has given us inthe microscopical proof of the bacillusin the sputa, an objective sign in thediagnosis of disease that is certain. Ithink from our present state of infor-mation on this subject that we cansay while the absence of the bacillusin the sputa is no certain proof of theabsence of the disease, its presence isconclusive. Its chief practical valuewill be found in the advance it willmake in prophylaxis. It will teachus to isolate the tubercular patientsin hospitals, to forbid as far as possi-ble the marriage, and especially inter-marriage, of tubercular people, to becareful to destroy the virus that dwellsin all egesta, to make laws prohibitingthe sale of milk from tubercular cows,and the time may come when tuber-culosis will not only be a preventablebut a prevented disease.