786 PATHOGENIC MICROORGANISMS 



thracis, and the individual bacilli more irregular in size. Very rapid 

 fluidification of gelatin and growth most active at room temperature. 

 Non-pathogenic. 



B. SUBTILIS (Hay Bacillus}. Although not very closely related to 

 the anthrax group, this bacillus is somewhat similar and conveniently 

 described in this connection. It is of importance to workers with 

 pathogenic bacteria, because of the frequency with which it is found 

 as a saprophyte or secondary invader in chronic suppurative lesions. 



Morphology and Cultivation. Straight rod, 2 to 8 micra long, 0.7 

 micron wide. Spores formed usually slightly nearer one pole than the 

 other. Grows in long chains and only in such chains are spores found. 

 It does not decolorize by Gram's method. Is actively motile in young 

 cultures in which the bacilli are single or in pairs. In older cultures 

 chains are formed and the bacilli become motionless. Gelatin is 

 liquefied. On gelatin and agar the bacilli grow as a dry corrugated 

 pellicle. Microscopically, the colonies are made up of interlacing 

 threads, being ^irregularly round with fringed edges. There is a 

 tendency to confluence. ! The bacillus is found in brackish water, 

 infusions of vegetable matter, etc., and is practically non-pathogenic, 

 occurring only occasionally as a saprophyte in old sinuses and 

 infected wounds. * 





