AVIAN TUBERCULOSIS 313 



masses or nodules. The bacilli of avian have the same 

 staining reaction as those of mammalian tuberculosis, but 

 on cultivation and inoculation various differences between 

 the two races become evident. Rats, guinea-pigs, and 

 rabbits are practically insusceptible to inoculation with 

 the avian bacillus. 



The mammalian bacilli flourish best at about 37 C., 

 and growth ceases at 41 C., whereas the avian bacilli 

 thrive luxuriantly at 43 C., and the growth of the latter 

 on glycerin agar is much moister and more wrinkled, and 

 often more pigmented, than that of the former. Fowls 

 and dogs are with difficulty infected with human bacilli, 

 but dogs are susceptible to infection with avian bacilli. 

 By cultivation on boric-acid agar and on eggs, etc., the 

 mammalian bacilli are stated to assume the characters of 

 the avian. 



Avian tuberculosis is of practical importance not only 

 as attacking poultry, but also in human pathology, as 

 several cases have been recorded in which the bacilli 

 cultivated from human cases seemed to be of the avian 

 type, and were therefore probably derived from an avian 

 source of infection. Two types of tuberculosis also occur 

 in the horse one in which the lesions are chiefly abdominal, 

 in the other the lungs and bronchial glands are most 

 affected. Nocard states that the bacillus obtained from 

 the pulmonary variety is generally of the ordinary mam- 

 malian type, while that of the abdominal one belongs to 

 the avian. 



Relation of human and bovine tuberculosis. It was 

 noticed long ago that there are certain differences between 

 the bacilli of human and of bovine tuberculosis, the latter 

 tending to be shorter and thicker and less readily culti- 

 vated than the former ; also, whereas human tuberculous 

 material injected into a rabbit generally produces small 

 discrete lesions which tend to retrogress, bovine material 



