Microhic Diseases Indimdualtij Comsidered. 249 



and two the generalized disease (Cadiot, Gilbert and 

 Roger). Avian tuberculosis which had acquired 

 greater virulence by passing through the organism 

 of the rabbit killed seven out of eight guinea pigs 

 which received it in the subcutaneous cellular tissue 

 (Courmont and Dor). In this case, therefore, the 

 bacillus from fowls behaved exactly like that from 

 mammals. 



According to an experiment of our own the avian 

 bacillus inoculated in the cellular tissue of the calf 

 causes a disease exactly like the human bacillus ; as 

 with the latter, the evolution is slow and remains for 

 a long time limited to the glands receiving the lymph 

 from the place of inoculation. 



The non-receptivity of fowls for mammalian tuber- 

 culosis is not absolute; out of numerous tests which 

 have been made a certain number have given positive 

 results ; the lesions, however, were always less gener- 

 alized than with the avian tuberculosis. 



Bacilli derived from avian tuberculosis, and which 

 had not passed through fowls for at least five years, 

 were found to have become more active for mammals 

 and produced a generalized tuberculosis in rabbits, 

 guinea pigs and chickens. From the liver of one of 

 those chickens four guinea pigs were inoculated, none 

 of which became tuberculous. A si ngle passage through 

 the chicken, therefore, was sutficient to impair the 

 virulence for mammals of these avian bacilli which 

 previously had acquired a virulence approaching that 

 of the human specimen. 



The bacillus of fowls becomes more active for mam • 

 mals and less active for fowls by passing through the 

 organism of mammals. This fact has been proved by 



