524 CLINICAL VETERINARY MEDICINE AND SURGERY. 



tuberculosis cannot be transmitted to the Gallinaceae : twenty fowls 

 inoculated under the skin, in the stomach, lung, peritoneum, and veins 

 all resisted. 



The interesting researches of Rivolta and Maffucci therefore again 

 rendered it doubtful whether tuberculosis is identical in various species 

 of animals. This doubt was shared by Koch, who announced at the 

 Berlin Congress that he had resumed the study of the question, and 

 that in his view the tuberculosis of birds was not in all respects similar 

 to that of mammals. At this time we published a preliminary note on 

 the same subject. Relying on a considerable number of experiments 

 we showed that avian tuberculosis can be transmitted to the Galli- 

 naceae ; that in the rabbit, intra-peritoneal inoculation with avian 

 material produces generalised miliary tuberculosis ; whilst in the 

 guinea-pig it usually produces either no lesion whatever, or only a few 

 little visceral tubercles. In some cases, however, avian, like human 

 tuberculosis, is capable of producing visceral granulations in the 

 guinea-pig. Nevertheless, speaking generally, the avian virus behaves 

 differently in the rabbit and guinea-pig. The latter animal, though 

 very sensitive to mammalian tuberculosis, appears very resistent to the 

 tuberculosis of Gallinaces. 



In spite of the differences which we observed between the two 

 viruses we at that time avoided coming to any fixed conclusion as to 

 their nature. 



Regarding the importance of these differential characters, we said : 

 " The bacilli of human and avian tuberculosis are regarded as two 

 distinct species, or two varieties of one species. At present it is very 

 difficult to settle the question ; study of other microbes has shown that 

 their form, development in various culture media, and powers of 

 resistance and virulence are by no means fixed quantities, and vary 

 under different circumstances. This question may possibly be cleared 

 up when we know how the bacillus of human tuberculosis behaves when 

 inoculated into birds." We therefore undertook researches in this 

 direction, and were led to regard the two bacilli as representing two 

 varieties of one species. 



During this time M. Nocard had resumed his previous experi- 

 ments. He again attempted to transmit mammalian tuberculosis to 

 the Gallinaceae. This time his results were negative, and he concluded 

 that in his first experiments he must accidentally have utilised a 

 number of fowls which had previously suffered from avian tuberculosis. 



Finally MM. Straus and Gamaleia, in an important memoir, demon- 

 strated in striking fashion the differences between the viruses of the 

 two tuberculoses. Among the new facts contributed by these savants 



