PATHOGENIC BACTETUA. 85 



Form. "Rods of variable length, nearly the size of a human 

 blood-corpuscle, broad cup-shaped ends ; in bouillon cultures, 

 long, threads are formed, with large oval spores. 



FIG. 43. 



Anthrax bacilli in human blood (fuchsin staining), Zeiss 1-12 oil immersion. 

 No. 4 ocular taken from Vierordt. 



Properties. Liquefies gelatine ; immotile ; the spores are very 

 resisting, living twenty years. 



Growth. Grows rapidly, between 12 C. and 45 C., and re- 

 quires plenty of oxygen, not growing without it ; grows well in 

 all media. 



Plates of Gelatine. Colonies develop in two days, white shiny 

 spots, which appear under microscope as slightly yellowish 

 granular-twisted balls, like a ball of yarn ; each separate string 

 or hair, if looked at under high power, being composed of bac- 

 teria in line. 



Stab Cultures. A white growth with thorn-like processes along 

 the needle-track ; later on, gelatine liquefied, and fiaky masses 

 at the bottom. 



Potato. A. dry creamy layer, and when placed in brood-oven, 

 rich in spores. 



