BACILLUS COLI COMMUNIS. 445 



Escherich, to degenerative changes in the protoplasm. 

 The colon bacillus does not form spores. There is 

 nothing in the morphology of this bacillus which is 

 characteristic or which may aid in its identification, 

 for in this respect it simulates many other organisms. 



FIG. 58. 



Colon bacilli. Twenty-four-hour agar culture. X 1100 diameters. 



The colon bacillus stains readily with the ordinary 

 aniline colors; it is quickly decolorized by Gram's 

 method. 



Biology. It is an aerobic, facultative anaerobic, non- 

 liquefying bacillus. It is motile, but its movements 

 are so sluggish that a positive opinion is often difficult, 

 being exhibited often by one or two individuals, in fresh 

 cultures, and at a high temperature only. These move- 

 ments are produced by flagella, which may be demon- 

 strated by Loffler's method of staining, though not 

 usually in such numbers as are seen to occur on the 

 bacillus typhosus. 



