8o 



are in his opinion fibrin threads and the like ; and there 

 is said to be a man in Virginia who still insists that the 

 earth is flat. 



You may have noticed that in this discussion the name 

 of Koch has not been mentioned a fact to which I call 

 attention, because a popular impression, not entirely con- 

 fined to the laity, saddles upon Koch the paternity not 

 only of the bacillus, but also of the infectiousness of tuber- 

 culosis. Dr. Formad, for example, says (p. 3) : " An 

 analysis of Koch's experiments shows that he has not 

 proved the parasitic nature of tuberculosis, so that the in- 

 fectiotisness of tubercular disease is still sub judice. " 1 1 i s 

 apparent from the facts which I have endeavored to sum- 

 marize that the communicability of tuberculosis was estab- 

 lished years before the well-known publication of Koch's 

 discovery. Dr. Formad says (p. 10) : " The supreme 

 question before the medical world is now, whether the 

 disease under consideration is really infectious." This 

 statement may represent faithfully that portion of the 

 world bounded by the city limits of Philadelphia ; the 

 supreme question before that portion of the medical 

 world including Virchow, Cohnheim, Billroth, Bamberger, 

 Weigert, Villemin, and the other German, French, and 

 Austrian pathologists and clinical teachers is, not 

 whether tuberculosis is infectious, but whether the bacil- 

 lus of Koch is the infective agent. For them the two 

 questions are quite independent the former established, 

 the latter awaiting confirmation. 



The numerous examinations of tuberculous tissues re- 

 vealed occasionally bacteria, which the discoverers were 

 but too willing to consider the cause of the disease ; 

 Klebs, Schiiller, and Aufrecht severally announced but 

 failed to demonstrate that the infective agent had been 

 found and that it was a bacterium. The lack of evidence 

 in support of their statements, as well as the reserve 

 with which such assertions in general were received, 

 combined to reduce to a minimum the attention bestowed 

 upon them. Such was the state of affairs when Koch 

 read before the Physiological Society of Berlin a paper 



