BIOLOGY AND MORPHOLOGY. 



269 



The bacillus can be stained with all the anilin dyes, but 

 must be exposed to the action of the stain for a long time. 

 To facilitate staining, it is advisable to use slightly warmed 

 staining solutions. It is decolorized easily, and for that reason 

 should not be washed in anything but water. Heavily stain- 

 ing granules have been seen in the body of the organism, and 

 also polar granules. These were at one time believed to be 

 spores, but because of their feeble resistance to heat and 

 chemicals this view is untenable. They are undoubtedly 



FIG. 124. 



Bacillus lypM abdommalis, from an agar-agar culture six hours old, showing the 

 flagella stained by Loeffler's method. X 1000. (Fraenkel and Pfeiffer.) 



polar granules or vacuoles caused by the drying and fixing 

 of the specimen preparatory to staining. Gram's stain is not 

 applicable. The flagella (Fig. 124) are easily stained by the 

 usual methods. The typhoid bacillus is used to demonstrate 

 the existence of flagella on bacteria. 



Bacillus typhosus is both saprophytic and parasitic. It is 

 a facultative anaerobe, but has very strong aerobic tendencies. 

 It will develop equally well at both the room and body tem- 

 perature, although the growth is most luxuriant at the latter. 



