II.— TUBERCULOSIS OF PARROTS— ITS RELATIONS 

 TO HUMAN TUBERCULOSIS. 



By MM. Cadiot, Gilbert, and Roger. 



When Koch discovered the bacillus of tuberculosis it was hoped 

 that the old unending dispute between the unicists and the dualists 

 would have ended. It has not been so ; the problem has only been 

 modified. Doubt no longer exists of the unicity of tuberculosis in 

 man, but the unicity of tuberculosis in animals is still disputed. 

 Some authors have attempted to draw a sharp line of demarcation, an 

 absolute distinction, between the pathogenic agent found in marhmals 

 and that discovered in birds ; have attempted, in fact, to prove the 

 existence of two distinct kinds of tuberculosis, human and avian. 



The question has more than a theoretical interest, for its solution 

 vitally affects hygiene. Depending on whether the avian bacillus 

 represents a particular variety or species, and is or is not capable of 

 developing in mammals, tuberculous birds ^must be considered dan- 

 gerous or innocent for man. If the avian bacillus has no relation to 

 that of mammals affected birds can be safely utilised for food, or kept 

 in close proximity to man without danger. 



It is impossible to deny that important differences exist between the 

 tuberculosis of mammals and that of birds. We have shown that the 

 avian bacillus, though very virulent for the rabbit, seldom produces in 

 the guinea-pig more than circumscribed discrete lesions, with a marked 

 tendency to undergo fibrous transformation. Conversely the human 

 bacillus is but slightly dangerous to the Gallinaceae, and its inoculation 

 into birds is seldom followed by the growth of tubercles. 



But there are exceptions to these rules : in the guinea-pig the avian 

 bacillus sometimes produces visceral lesions of an extremely marked 

 character, which can be transmitted in series. Moreover the Gallinaceas 

 are not entirely immune : of eighty-six fowls inoculated with mamma- 

 lian tuberculosis nine showed positive results, i. c. a proportion of 

 about 10 per cent. 



Although the Gallinaceae show unquestionable resistance, other 



