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



Staining properties. Gram-positive. 



Spore formation. Spores begin to form within 24 hours. By 

 the end of the 2nd day the spores are abundant. They arise in 

 the center or towards one end of the organism and bulge the rod 

 but Uttle. The free spores retain rims of protoplasm often 

 greater in quantity at one end than at the other. They resemble 

 the mesentericus spores and measure usually 0.625 by 0.75 to 1.5 

 microns. As they mature they lose their rims of protoplasm, 

 become more oval and measure 0.5 to 0.625 by 0.75 to 0.875 

 microns. 



Agar slant. Moist, smooth, non-spreading lemon-yellow 

 growth. The lemon-yellow color becomes more pronounced with 

 age. 



Agar stab. Profuse granular growth along line of stab with 

 slight irregular outgrowths. 



Agar colonies. The colonies are smooth, moist, round, with no 

 tendency to spread, glistening and raised, lemon-yellow in color. 

 There is a definite opaque yellow center while the periphery is 

 translucent and shell-like. Deep colonies have a tendency to 

 spread and become faintly iridescent. 



Glucose litmus agar slant. A very scant, moist, granular and 

 sHghtly yellow growth is produced with a slight acid reaction. 



Glucose litmus agar colonies. Colonies similar to those on 

 agar but less profuse. Reaction of medium acid. 



Gelatin stab. A very slow liquefaction is produced along the 

 line of stab and a slight yellow tinge is imparted to the medium . 



Gelatin colonies. The colonies rest in slight depressions caused 

 by slow liquefaction. They are dark yellow in color, moist, round 

 and smooth. Under the low power of the microscope each 

 colony is seen to be composed of concentric circles of varying 

 densities with lobate edges. 



Broth. A slight turbidity appears after a considerable pe- 

 riod. The medium clears by sedimentation and the sediment has 

 a sHght yellow tinge. 



Peptone. A slight turbidity, somewhat less than in broth 

 occurs. This soon settles to the bottom. 



Potato. No visible growth. 



