290 J. S. LAWRENCE AND W. W. FORD 



what thicker and longer on glucose agar measuring 0.5 by 1.5 

 to 4 microns. Does not usually form threads on this medium. 

 (Figures 4 and 5.) 



Motility. Sluggishly motile in young cultures. 



Staining properties. Gram-positive. 



Spore formation. Spores are formed early appearing within 

 24 hours on plain and glucose agar. They arise in the center or 

 towards one end of the rods and are slightly greater in diameter 

 than the rods, thus causing a distinct bulging. The free spores 

 may retain bits of protoplasm at each end, often unequal in 

 amount, giving the spore a characteristic appearance. Such 

 spores measure about 0.5 by 0.875 microns. The spores rapidly 

 lose their protoplasm, become more oval and measure about 0.5 

 by 0.75 microns. 



Agar slant. Weakly refractive, glassy, membranous growth 

 along line of inoculation, later spreading out over entire surface 

 of agar. The surface is usually dry and hard, but in old cul- 

 tures it becomes soft and smeary, but is always firmly attached 

 to the agar from which it cannot be scraped off. 



Agar stab. Little growth along the line of inoculation but a 

 spreading, dry, membranous growth on the surface of the agar, 

 extending to the wall of the tube. 



Agar colonies. Surface colonies weakly refractive, spreading 

 concentrically or in amoeboid fashion from small dense nuclei. 

 Under the low power edges may be complete or finely crenate. 

 If water of condensation be present one or two colonies frequently 

 overgrow the entire plate. Under the low power the colonies 

 are homogeneous and granular or irregular and gyrose. The 

 deep colonies are punctiform and under the lower power lichen- 

 like with irregular margins myceleoid in character. The colonies 

 are usually membranous dry, hard, and glassy, and can be sepa- 

 rated from the agar only with great difficulty. 



Glucose litmus agar slant. Highly refractive growth verrucose 

 or vesicular, with milky liquid in vesicles, not spreading. Parts 

 of growth show distinct red pigment. Acid is produced in 24 

 hours, but is replaced by alkali in about ten days, medium turn- 

 ing deep blue. 



