AVIAN TUBERCULOSIS. — SUMMARY AND CONCLUSIONS. 557 



sideration all the characteristics of the two microbes. From this 

 point of view we should bear in mind that a number of facts tend to 

 prove a community of nature between the two viruses. The rabbit, 

 for example, contracts avian as readily as human tuberculosis, at least 

 when inoculated intra-peritoneally. Although the guinea-pig, the test 

 par excellence for human tuberculosis, usually resists the avian disease,, 

 it nevertheless sometimes dies with generalised visceral granulations. 

 Conversely the fowl is not absolutely immune against human virus ; 

 on several occasions we have seen tuberculous lesions produced in the 

 fowl, and in one case we were able to prove that the lesions were due 

 to the human bacillus, which had preserved its particular characters. 



Finally, we have cited in this investigation various results which 

 tend to establish that the two viruses may undergo modification, and 

 even transformation ; in one case human tuberculosis was transmitted 

 from one fowl to another ; in another avian tuberculosis by passage 

 through mammals became exalted in virulence for these animals, but 

 lost its pathogenic properties for the Gallinaceas. 



The results we have obtained, and those reported by other experi- 

 menters, lead us to think that the two bacilli only represent two 

 varieties of the same species. Without doubt these two varieties are 

 very different, and it is impossible to apply to one results obtained 

 with the other. To prevent a recurrence of the confusion which pre- 

 viously obtained, it is, therefore, always necessary to state which virus 

 has been used. But, despite their very important distinguishing charac- 

 ters, a common basis exists on which these two pathogenic agents 

 may be compared and regarded as derived from a single source. The 

 view which we think best agrees with hitherto observed facts is that 

 tuberculosis of mammals and of Gallinacese are essentially one and the 

 same. 



