The bacillus tuberculosis and the etiology of tuberculosis : is consumption contagious? : second communication, read, by invitation, before the Philadelphia County Medical Society, November 14, 1883 / by H.F. Formad.

  • Formad, H. F. (Henry F.), 1847-1892.
Date:
1884
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Licence: Public Domain Mark

Credit: The bacillus tuberculosis and the etiology of tuberculosis : is consumption contagious? : second communication, read, by invitation, before the Philadelphia County Medical Society, November 14, 1883 / by H.F. Formad. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    in the laboratory upon a large quantity of material, I regard it as a fact, that the tuber- cle-bacillus of Koch is a mere concomitant of cheesy disintegrated materials, even if it be pre-eminently of tuberculous cheesy ma- terials. 4. Given a parasite that is the cause of a disease, it should, when isolated and in- oculated into an animal liable to that dis- ease, always reproduce that disease ; but its action should be specific,—i. e., it (the para- site') alone should be the causative factor. There is no doubt that Koch’s tubercle- bacillus when isolated and cultivated for many generations and then inoculated into certain animals is capable of inducing tuberculosis, ora nodular eruption not dis- tinguishable from it, more readily than other irritants, so far as tried. Success in inoculating is particularly frequent in rab- bits and guinea-pigs (although not so common as Koch claims), but only condi- tional and rare in other animals. Thus it appears that the above proposi- tion could be answered for tuberculosis and the bacillus in the affirmative if only the following points were proved : 1st. That the nodular lesion thus in- duced is really tuberculosis, identical with the human disease. 2d. That this bacillus is the only bac- terium or the only irritant capable of inducing tuberculosis ; and, 3d. That its action is specific,—i.e., that the bacillus is the only agency or factor at work, the sole cause of the disease. The first point is not proved, as prob- able as it may appear. The other points are open to the following considerations and objections : It has been proved that in tuberculosis micrococci, as well as bacilli, are causal, the evidence being “strong” for either “parasite;” whereas the bacillus alone should be the causal factor. As long as not disproved, Klebs’s, Toussaint’s, and Schuller’s investigations (in relation to the micrococci as causal factors) have as much claim as Koch’s. The method of culti- vating those tubercle-micrococci, as prac- tised by those investigators, was one not favorable for the development of the tu- bercle-bacilli. Further, Watson Cheyne’s assertion that bacilli must have been pres- ent in the cultured materials with which those investigators inoculated successfully, is altogether a gratuitous assumption, and his few and imperfect control experiments with Toussaint’s micrococci were not sat- isfactory, and, in fact, neither prove nor disprove anything.* Koch did not try the effects of any other fungus than that of his bacillus in relation to tuberculosis. Koch further claims that the specific character of his bacillus is supported by the rapidity of its effects, and brings forward the inhalation experiments of Tappeiner and the experiments upon the eye. The former I have shown to be valueless, as those nodules produced in the lung, espe- cially if rapidly formed, are not tubercles. I have also reason to believe that the same is the case with many of the experiments on the eye, especially in those cases in which an apparently acute miliary tuber- culosis of the lung rapidly followed the inoculation : in fact, in some instances this eruption occurred in a much shorter time than is at all possible for tubercles to develop. Koch has not proved that his bacillus is the only agency at work in the production of tuberculosis. Although he undoubtedly inoculated the pure bacillus, he ignored the specific reaction of the soil; and it is the latter which I hold plays the most im- portant role in determining the formation of tubercle. In introducing the bacillus into the animal organism, another factor —the injury inflicted, and its effects upon the living cells of the body—must be taken into consideration. In some animals all the tissues of the body react equally upon the introduction of irritants; in others only some one of the tissues responds, such as the serous membranes. This surely demonstrates the specific action of the soil. I must again call attention to the fact that in making his experiments Koch injected the bacilli into any part indiscriminately in scrofulous animals, while in non-scrofulous animals (dogs, rats, cats) he injected them only into the peritoneum or the anterior chamber of the eye, where, we know from experience and from repeated experiments, any irritant of sufficient intensity may create tuberculosis. I his cannot be explained by the assump- tion of Koch that the bacillus must merely be enclosed in something so as not to be eliminated before it can exert its effect. To me it appears that the reason why we must inoculate in serous cavities to pro- * See Watson Cheyne’s report. Practitioner, April, 188a PP. 272-276. '