AEROBIC SPORE-BEARING NON-PATHOGENIC BACTERIA 499 



Litmus milk. No change in reaction even after a long period 

 of time. 



Blood serum. A scant, moist, smooth, glistening and yellow- 

 ish growth is produced. No solution of the medium occurs. 



Fermentation tubes. Glucose : a slight turbid growth occurs in 

 the bowl with the production of a slight acidity. 



Saccharose : the same appearance. No acid. 



Lactose: shght turbidity. No acid. 



Thermal death point. Spores survive 18 pounds pressure in 

 the autoclave but are destroyed by 20 pounds. They survive one 

 hours steaming in the Arnold. 



Bacillus ruminatus Gottheil 1901 



The type ''ruminatus" was first described by Gottheil (1901). 

 In morphology and cultural characters it closely resembles Bacil- 

 lus megatherium from which it is distinguished by its porcelain- 

 white growth, particularly in young cultures. The present de- 

 scription applies to an organism found in dust and subsequently 

 in water which corresponds to Gottheil's original description 

 but not however to that given by Chester. We believe that it 

 may properly be called Bacillus ruminatus. 



Morphology. Homogeneous rods with rounded ends measur- 

 ing 0.625 to 0.75 by 2.5 to 4 microns in young cultures on plain 

 agar. On glucose agar they are distinctly thicker and longer 

 measuring 0.75 to 1.125 by 2.25 to 5 microns. Rarely, long 

 forms are found on this medium measuring 8 to 10 microns in 

 length. Shadow or washed out forms are common on both plain 

 and glucose agar measuring 1.025 to 1.5 by 3 to 5 microns. Or- 

 ganisms often appear in short chains. (Figures 58 and 59.) 



Motility. Active motility in young cultures. 



Staining properties. Gram-positive. 



Spore formation. Spores are formed early, often in 48 hours, 

 especially when the strains are first isolated. They are central or 

 sHghtly ex-centric and on sporulation swell or bulge the organ- 

 isms from which they spring. They measure usually 0.625 by 

 1.25 to 1.5 microns. Some spores are however somewhat 

 smaller and more oval. 



