MYCOBAOTEEIUM TUBEBCULOSIS p AVIUM. 419 



In favor of this are the observations of Kruse and 

 Pansini. From a guinea-pig, inoculated with the juice 

 from tuberculous organs of cattle, and from another in- 

 fected with human sputum, typical fowl tubercle bacilli 

 were cultivated which were pathogenic for chickens. 



In accord with this, Johne and Frothingham found 

 fowl tuberculosis in cattle (C. B. xix, 564) and Nocard 

 in horses (C. B. xxi, 807). 



After prolonged cultivation on artificial nutrient media 

 at ordinary incubator temperature, the bacillus of fowl 

 tuberculosis becomes pathogenic also for mammals 

 (Courmont, C. B. xiv, 602). Fischel (C. B. xiv, 632) 

 observed transition forms connecting the two diseases. 

 Finally, Cadiot, Gilbert, and Roger were able to invert 

 the pathogenic properties of both varieties by continued 

 transfer (C. B. xix, 567). 



The following are given as the points upon which the 

 differential diagnosis of the avian form rests. 



Microscopic Appearance. — Like the T. B., some- 

 times a little longer and slimmer. Staining properties are 

 the same. 



Requirements as to Nutrient Media. — Does not 

 grow on potato; otherwise the same as the T. B. 



Requirements as to Temperature. — Limits, 35°- 

 45°. In contradistinction to the T. B., it grows very well 

 and without reduction of virulence at 43° (Straus and 

 Gamaleia). The T. B. generally does not grow above 42°. 



Serum and Agar Cultures. — They are always softer, 

 more succulent, more luxuriant, and grow more on a 

 level. However, Kruse has observed a dry culture, also 

 cultures which, upon certain varieties of agar, take on a 

 reddish, blackish, violet color. 



Fluid Nutrient Media. — The pellicle is not so firm as 

 in the T. B. 



Cultures live for two years. 



Pathogenic for birds ^ when introduced in every way 

 except by feeding, attacking especially the liver and 

 spleen. Also the embryos of chickens in incubated eggs 



' The very common tuberculosis of parrots is usually produced by 

 true T. B. , the animals being infected by receiving food from the 

 mouths of tuberculous persons. 



