79 



however that may be settled, let us not confound a fact 

 with a possible deduction which may be unpleasant. 



These more or less prevalent arguments against the in- 

 fectiousness of tuberculosis have been considered not 

 because they have any bearing upon the question, but 

 because there are those who will not or do not take into 

 consideration the demonstrations attained by accurate ex- 

 perimental methods, and whose opinions rest upon dis- 

 torted deductions from necessarily inaccurate clinical 

 observations. Yet while those who are pleased to regard 

 pathology as something extrinsic to practical medicine 

 are still discussing the clinical proofs of the infectiousness 

 of tuberculosis, it is quite otherwise with pathologists and 

 clinicians whose opinions are founded upon knowledge 

 without prejudice. One after another the German and 

 French pathologists (who are not infrequently clinical 

 teachers as well), honest in their previous conviction 

 that the communicability of tuberculosis was not proven, 

 honestly recorded their convictions as succeeding proofs 

 were furnished, that the case was reversed ; so that three 

 years ago Cohnheim said, "To-day there scarcely exists 

 a pathologist who would deny that tuberculosis is a com- 

 municable disease." 1 



Cohnheim himself, extending and repeating more care- 

 fully his observations, saw and acknowledged the error 

 of his former deduction. True, a would-be pathologist 

 has occasionally reminded us that he was not yet con- 

 vinced ; yet even Schottelius, the last of them, has finally 

 yielded the point. There have been in all ages, and on 

 all questions, similar psychological curiosities ; twenty- 

 five years ago it was maintained on the floor of the 

 French Academy of Sciences that intestinal worms origi- 

 nate de novo in a peculiar influence pervading the system 

 the vermicular diathesis. There is a gentleman in this 

 State who recently reminded us that bacteria, so-called, 



1 In the Medical News, January 27, 1883, p. 94, Dr. Wm. Hunt leads us to 

 infer that "most recent pathologists " agree in regarding tuberculosis as the result 

 of a simple inflammation. Will he kindly name one pathologist who now holds this 

 opinion, and mention the pertinent publication? 



