BACILLI 417 



BACILLUS SUBTILIS (Hay bacillus) 



I LIQUEFIES GELATINE I 



Authority. — Ehrenberg. 



"Where Found. — In hay infusions, air, water, faeces, and in putrid liquids. 



Microscopic Appearance. — Bacillud resembling the anthrax bacillus, but 

 somewhat narrower and with rounded ends. It is about 6 m long and three 

 times as long as broad ; grows out into long threads. The bacilli have flagella. 

 It is motile, its movements being of a wobbling character. Forms egg-shaped 

 shining spores about 1-2 /x long and 0;6 m broad. They will bear exposure to 

 dry heat of 120° C. for over one hour. (See Plate I. 2e, 2d.) 



Cultures.— 



Gelatine Plates. — The colonies become visible to the naked eye in about 

 two days' time as small white dots in the depth, whilst on the surface they 

 exhibit a very small liquefied circle of a greyish hue. Under a low power the 

 depth colonies are irregular in contour with short spinose extensions in parts of 

 the circumference, whilst the interior has a wavy structure, as if composed of 

 coiled threads. With increasing size the internal structure becomes less defined, 

 wbilst the edge becomes uniformly spinose. In about two days' time the surface 

 of the gelatine exhibits in places small cloudy expansions, which under a low 

 power are seen to consist of parallel bands of fine threads arranged in a much 

 contorted pattern. This appears to be the form assumed by the colonies on 

 first reaching the surface of the gelatine, for these colonies in a day or two 

 produce a liquefied surface with the usual spinose margin (Percy and 

 G. C. Frankland, Phil. Trans., 1887). (See Plate I. 2a, 2b, 2c.) 



Gelatine Tubes. — Forms a long, funnel-shaped liquefying channel, the 

 lower part of which throws out feathery lateral extensions. The whole of the 

 gelatine becomes fluid and a tough white pellicle forms on the surface, and a 

 large quantity of flocculent matter collects at the bottom of the tube. 



Agak-agae. — Forms rapidly a white opaque expansion which becomes dry 

 and copiously wrinkled and puckered. 



Broth. — Eenders the liquid turbid ; produces a white deposit, and a pellicle 

 which gradually increases in thickness and tenacity. 



Potatoes. — Forms a, moist white cream-like expansion over the whole 

 surface. 



Blood Serum. — It liquefies the serum, forming a wrinkled pellicle on the 

 surface. 



Kemarks. — It is not pathogenic. It is strictly aerobic. 



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