328 BACTERIOLOGY. 



resisting decoloration with an acid have been found in cer- 

 tain eye affections. 



4. Pseudo-tuberculoses. The preceding case may be 

 said to fall under this head. There are, however, bacteria 

 which give rise to tubercles or nodules but otherwise are 

 easily distinguished from the tubercle bacillus. They are 

 easily cultivated and stain with the ordinary dyes, but do 

 not give the double stain like the tubercle bacillus. 

 Pseudo-tuberculoses are rare in man, though rather com- 

 mon in animals (sheep, chicken, rabbits, etc.). 



5. Aviary tuberculosis. The bacillus present in the or- 

 dinary bird tuberculosis stains like the tubercle bacillus. 

 It grows more rapidly on various media and forms a moist 

 soft growth, which unlike that of the tubercle bacillus, will 

 easily form a cloudy suspension when stirred into water. 

 Guinea-pigs when injected subcutaneously react with 

 a local affection, whereas intraperitoneal injection into 

 a chicken yields general tuberculosis. The rabbit is 

 susceptible to both organisms. The tubercles do not show 

 giant- cells. The bacillus can grow at a higher tempera- 

 ture than the tubercle bacillus, but otherwise the growths 

 on the various media are very much alike. The aviary 

 tubercle bacillus may naturally infect man, rabbits, and 

 other animals. It has always been believed to be a variety 

 of the mammalian tubercle bacillus. Cultures in collodium 

 sacs seem to prove that the aviary bacillus can be trans- 

 formed into that of mammals. 



6. Fish tuberculosis. This organism was isolated from 

 a small tumor on a carp. The presence of giant cells and 

 the histological structure pointed to tuberculosis. The 

 bacillus present stained like that of tuberculosis, but was 

 culturally different. It grows best at 23-25 and does not 

 grow at 39. It would seem as if the mammalian tubercle 

 bacillus on passage through cold-blooded animals (fish and 

 frogs) gave rise to a variety, as in the case of bird tuber- 

 culosis. 



