332 DISTRIBUTION OF BACTERIA 



ally invade the intestine. For example, B. coli is a frequent 

 cause of pyogenic or pus infections in the intestine, and in con- 

 nection with B. typhosus, for example, may do much to in- 

 crease the severity of the infection. 



Besides the many non-pathogenic bacteria which are present 

 in the intestine normally, at certain times pathogenic bacteria 

 may invade these parts of the body, grow, and produce most 

 virulent infections. B. typhosus, B. dysentariae, Msp. comma, 

 are among this class of microorganisms. 



