DESCRIPTIONS OF PATHOGENIC BACTERIA. 157 



of the rods vary with the conditions of nutri- 

 tion. In the blood they occur isolated or in 

 short threads ; in culture fluids outside of the 

 body, however, they proliferate into long mat- 

 ted filaments. Attenuated anthrax bacilli can 

 also form long threads in the blood which re- 

 semble those of the bacillus of malignant 

 oedema. The anthrax bacillus stains by 

 Gram's method. In cultures it is not exact- 

 ing ; it thrives in gelatin, agar, and bouillon, 

 and upon potato, and forms characteristic col- 

 onies of tangled threads. In bouillon it forms 

 below the surface festoons of intertwined fila- 

 ments. It grows between i2-42 C, and 

 thrives best at blood temperature ; above 42, 

 its growth is perceptibly interfered with. En- 

 dospores.are formed between 18 and 42, but 

 with the higher temperatures they are formed 

 more quickly and abundantly. The organism 

 is a typical bacillus. Free oxygen is neces- 

 sary for spore-formation, hence this process can 

 occur only outside of the animal body. Certain 

 methods of staining show that in the blood the 

 individual rods are usually not rounded at the 

 ends, but are square-cornered or even swollen 

 like joints of bamboo, while unstained rods 

 from fresh cultures, and often also those from 

 blood appear rounded ; in the blood also cap- 

 sules around the bacilli are often plainly visible. 



