THE COLON, TYPHOID AND DYSENTERY BACILLI 



331 



commonly occurring single or in short threads, stains readily 

 with anilin dyes and is Gram-negative. It is actively motile and 



FIG. 134. Bacillus typhosus showing flagella. (After McFarland.} 



possesses 10 to 20 peritrichous flagella. Spores have not been 

 observed. 





A B 



FIG. 135. Colonies on gelatin plate two days old of (^4) Bacillus typhosus, and (B) 

 Bacillus coli. Y^ZT.. (From Jordan after Heim.) 



The organism grows readily on ordinary media but not so 

 luxuriantly as B. coli. The colony is smaller but relatively more 



