Metabolic Products 405 



the culture is old, the agar-agar usually becomes brown in 

 color. Spore formation is luxuriant. 



Bouillon. In bouillon the anthrax bacillus, because of its 

 marked affinity for oxygen, grows chiefly upon the surface, 

 where a thick felt-like pellicle forms. From this, fuzzy ex- 

 tensions descend into the clear bouillon below. After a few 

 days some wooly aggregations can be seen in the bottom of 

 the tube. In the course of time the growth ceases and the 

 surface pellicle sinks. If, by shaking, it is caused to sink 

 prematurely, a new, similar surface growth takes its place. 

 Spore formation is rapid at the surface. 



Potato. Upon the potato the growth is white, creamy, 

 and rather dry. Sporulation is marked. 



Blood-serum. Blood-serum cultures lack characteristic 

 peculiarities; the culture-medium is slowly liquefied. 



Milk. The anthrax bacillus grows well in milk, which 

 it coagulates and acidulates. Later the coagulum is pep- 

 tonized and dissolved, leaving a clear whey. The reaction 

 is not altered. Iwanow* found that the organism forms 

 acetic, formic, and caproic acids. 



Thermic Sensitivity. The bacillus grows between the 

 extremes of 12 and 45 C., best at 37 C. The exposure of 

 the organism to the temperature of 42 to 43 C. slowly di- 

 minishes its virulence. 



When dried upon threads, the spores retain their vital- 

 ity for years, and are highly resistant to heat .and disinfec- 

 tants. The spores of anthrax are killed by five minutes' 

 exposure to 100 C. It is said by some that spores sub- 

 jected to 5 per cent, carbolic acid can subsequently ger- 

 minate when introduced into susceptible animals, their 

 resistance to this strength carbolic solution being so great 

 that they are not destroyed by it under twenty-four hours. 

 They are killed in a short time by exposure to i : 1000 

 bichlorid of mercury solution. 



Metabolic Products. The anthrax bacillus produces a 

 curdling ferment. It produces no important change of 

 reaction in the medium in which it grows, and generates no 

 indol. Its proteolytic enzyme is active, digesting both 

 casein and fibrin. 



It is doubtful whether the anthrax bacillus produces any 

 important toxic substance. Hoffaf isolated a basic sub- 

 * "Ann. de 1'Inst. Pasteur," 1892. 

 t "Ueber die Natur. des Milzbrandgifts," Wiesbaden, 1886. 



