TUBERCULOSIS. 191 



separate species. Morphologically, trie organisms are 

 .similar, the bacillus of fowl-tuberculosis being a little 

 longer and more slender than its ally. 



Upon culture-media a distinct rapidity of growth is 

 observable, and we find that, instead of growing only 

 where glycerin is present, the Bacillus tuberculosis galli- 

 narum will grow upon blood-serum, agar-agar, and bouil- 

 lon as ordinarily prepared. It will not grow upon potato. 

 The bacillus will grow at 42-43 C. quite as well as at 

 37 C., while the growth of the tubercle bacillus ceases 

 at 42 C. Moreover, the temperature of 43 C. does not 

 attenuate its virulence. The thermal death-point is 70 

 C. Upon culture-media it can retain its virulence for 

 two years. 



The growth upon artificial culture-media is luxuriant, 

 and lacks the dry quality characteristic of ordinary 

 tubercle-bacillus cultures. As it becomes old a culture 

 of fowl-tuberculosis turns slightly yellow. 



Birds are the most susceptible animals for experimental 

 inoculation, the embryos and young m6re so than the 

 adults ; guinea-pigs are quite immune. Artificial inocu- 

 lation can only be made in the subcutaneous tissue, never 

 through the intestine. The chief seat of the disease is 

 the liver, where cellular nodes, lacking the central coag- 

 ulation and the giant-cells of mammalian tuberculosis, 

 and enormously rich in bacilli, are found. The disease 

 never begins in the lungs, and the fowls which are dis- 

 eased never show bacilli in the sputum or the dung. 



Rabbits are easily infected, an abscess forming at the 

 seat of inoculation, and later nodules forming in the 

 lung, so that the distribution is quite different from that 

 seen in birds. 



The bacillus stains like the tubercle bacillus, but takes 

 the stain rather more easily. The resistance to acids is 

 about the same. 



Pseudo-tuberculosis. Eberth, Chantemesse, Charrin, 

 and Roger have reported certain cases of so-called pseudo- 

 tuberculosis. The disease occurred spontaneously in 



