508 C. A. LAUBACH, J. L. RICE AND W. W. FORD 



Gelatin colonies. The colonies are definitely circumscribed 

 and rest in a cup-like excavation due to liquefaction. They are 

 translucent, grayish, viscous with opaque centers. 



Broth. A granular, lace-like scum is formed which settles to 

 the bottom. A flocculent growth occurs throughout the medium. 



Peptone. Growth similar to that in broth. 



Potato. A profuse, grayish, slightly glistening and viscous 

 growth is produced. More characteristic is the appearance of 

 numerous blebs filled with gelatinous material on the entire 

 medium within 24 hours. Later the growth becomes dry and 

 scale-like. 



Litmus milk. Within 24 hours a slight reduction of the lit- 

 mus. Within 24 hours a thickening occurs at the bottom and 

 peptonization begins. This progresses rapidly and within four 

 days the process is generally completed. There remains first a 

 port-wine, then an amber-colored fluid. 



Blood serum. The growth is scant, glistening and bluish-gray. 

 There is occasionally a fine wrinkling. A gutter-like excavation 

 along the line of inoculation is often visible. Within 96 hours 

 a pinkish tinge is produced in a wrinkled scum if water of con- 

 densation be present at the bottom of the tube. 



Fermentation tubes. Glucose: a turbid growth occurs in the 

 bowl and neck with the formation of a thin smooth bluish-gray 

 scum. Some acidity is produced. 



Saccharose: a similar growth is apparent but the scum is 

 finely granular. Here also a definite acidity is produced. 



Lactose: the growth is identical with that in saccharose but 

 the reaction remains neutral or becomes alkaline. 



Thermal death point. Spores survive 15 pounds in the auto- 

 clave but are killed by 20 pounds pressure. They are killed 

 within an hour in the Arnold sterilizer. 



/ 



Bacillus cereus variety fluorescens. no v. var. 



An organism producing a greenish fluorescence has been en- 

 countered frequently in water and in soil. It does not agree 

 with any previously described organisms in its cultural reactions, 



