The flagellated pathogenic types are mainly intestinal where con- 

 ditions favorable to peritrichous flagellation may exist to some 

 extent. The plant pathogens, however, are generally flagellated, 

 both polar and peritrichous. This may indicate that much of their 

 existence is in water and soil. Instances of mutations from non- 

 flagellated to flagellated types appear to be very rare and have 

 never(?) been observed in genera other than those which he- 

 some species which normally are flagellated. 



ave 



19 



