226 



MANUAL OF BACTERIOLOGY. 



its very resistant spores. The hay bacillus is entirely with- 

 out pathogenic properties. 



FIG. 49. 



Bacillus subtilis. (X 1000.) 



Bacillus erythrosporus. Found in decomposing fluids 

 and water; a slim bacillus with rounded ends; motile; does 

 not liquefy gelatin; facultative anaerobic; forms oval, red- 

 colored spores, two to eight in each filament ; grows rapidly, 

 only at ordinary temperatures; produces a greenish-yellow 

 fluorescent pigment. On potato it forms a limited, reddish 

 growth, becoming nut-brown. 



Bacillus cyanogenus (Bacterium syncyanum, Bacillus 

 lactis cyanogenus, Bacillus of blue milk). A bacillus of 

 variable size, with rounded ends; motile; spore formation 

 doubtful; is aerobic; not stained by Gram's method; grows 

 rapidly at ordinary but not so well as incubator tempera- 

 tures on the usual culture-media ; does not liquefy gelatin ; 

 produces a grayish-blue pigment, brighter in acid media, 

 at ordinary temperatures; milk is not coagulated, or ren- 

 dered acid. 



