100 



ESSENTIALS OF BACTERIOLOGY 



Immotile. 

 Stain. Gram. 



A gar Stroke. Gray soft mass, gnarled and twisted; feath- 

 ery extensions spreading over entire surface. 



Gelatin Stab. Arborescent and plumose-parallel projections 

 on either side of the stab; a thick skin on surface with slow 

 liquefaction (Fig. 40). 



Colonies. Twisted threads, like a bundle of hair; opaque 

 center; the threads or branches divide endlessly, forming coils. 

 Growth. At ordinary temperature, 

 with plentiful supply of air. 



Staining. Spores stain readily with 

 the ordinary spore stain. 



Bacterium Zopfii (Kurth) (1883). 

 Origin. Intestines of a fowl. 



Form. Short thick rods forming long 

 threads coiled up, which finally break up 

 into spores, which were once thought to 

 be micrococci. 



Properties.- Very motile; does not 

 dissolve or liquefy gelatin. Produces 

 putrefaction in albuminous media, with 

 gas formation. 



Growth. In thirty hours abundant growth ; aerobic; grows 

 best at 20 C. 



A gar Plates. Small white points which form the center of a 

 very fine netting. With high power this netting is found 

 composed of bacilli in coils, like braids of hair. 



Excellent impress or "Klatsch" preparations are obtained 

 from these colonies. 



Staining. Ordinary dyes and Gram. 

 Bacillus Subtilis (Hay Bacillus) (Ehrenberg). Origin. 

 Hay infusions; found also in air, water, soil, feces, and 

 putrefying liquids. Very common, often contaminates cul- 

 tures. 



Form. Short, thick rods, three times as long as broad; 

 slight roundness of ends; seldom found singly; usually in 



Fig. 40. Bacillus 

 mycoides (Frost). 



