D 



FIG. 206. Groups of bacteria stained to show their cilia 



Bacillus subtilis, an organism of decay characteristic of hay infusions ; B, Bacil- 

 lus typhi, the germ of typhoid fever; C, Bacillus vulgaris, single cells and 

 filaments ; D, Planococcus citreus, which forms yellow colonies on various sub- 

 strata ; E, Pseudomonas syncyanea, which turns milk blue ; F, other species 

 of Pseudomonas ; G, Microspira comma, the germ of Asiatic cholera ; H, Spi- 

 rittum undula, in water containing decaying fish, alga?, etc. ; /, another species 

 of Spirillum. After Migula 



229 



