AEROBIC SPORE-BEARING NON-PATHOGENIC BACTERIA 315 



tures. On glucose agar the organisms retain the same diam- 

 eter but grow out into long chains which often assume spiral 

 arrangements. (Figure 52.) 



Spore formation. Spores are formed slowly seldom appearing 

 before 48 hours. They are cyhndrical, thicker than the rods 

 from which they spring, terminal or sub-terminal, giving the 

 organisms a clavate or club-shaped appearance. Free spores are 

 0.75 by 1.5 microns in dimensions. 



Motility. Active motiUty in 24 hour cultures. 



Staining properties. Gram-negative. 



Agar slant. Thin spreading smooth glistening growth with 

 gradual darkening of the agar. 



Agar stab. Faint growth along line of puncture and on the 

 surface at the point of inoculation. 



Agar colonies. Colonies grow slowly appearing only after 

 3 to 4 days. They are round, regular, under low power showing 

 central nuclei with thin spreading peripheries. Deep colonies 

 apt to be irregular under low power, showing clean-cut or entire 

 edges. 



Glucose agar. Faint white filmy growth with an alkahne re- 

 action. 



Gliicose agar colonies. Thin slow-growing spreading surface 

 colonies, under low power showing dense central nuclei and thin 

 margins. Deep colonies punctiform, under low power shghtly 

 granular with irregular margins. Reaction alkahne. 



Gelatin stab. Growth along Une of inoculation and slow cup- 

 shaped liquefaction. 



Gelatin colonies. Colonies on the surface show dense central 

 nuclei and concentric spreading peripheral margins. Deep 

 colonies punctiform and tend to show same arrangement. Under 

 low power edges entire. 



Broth. SHght turbidity. No scum. No sediment. Fragile 

 scum described by Fliigge. 



Peptone. Slight turbidity. No scum. No sediment. 



Potato. No visible growth in our isolations. Faint moist 

 growth gradually becoming thicker and yellowish, noted by 

 Fliigge. 



