MORPHOLOGY OF CAUSATIVE AGENTS. 



121 



active, although it may at times be wanting completely. 

 The motile varieties possess flagella. For staining, Loffler's 

 methylene-blue solution or carbolfuchsin is most available. 

 The bacteria do not stain by Gram's method. They thrive 



ASS 



ig- 43- Bacillus coli communis, from an agar-agar culture ; X 1000 (Itzerott and 

 Niemann). 



Fig. 44. Bacillus coli communis : superficial colony two days old upon a gelatin-plate ; 



X 21 (Heim). 



best at body-temperature, although they grow well, also, at 

 room-temperature. Upon gelatin-plates (Fig. 44) there 

 form deeply situated, yellow, punctate colonies. The 

 superficial colonies either spread upon the surface, possess 



