Bacillus Butyricus, Hueppe. 



Origin. — Milk. 



Form.— Long-, narrow rods, with rounded ends, fre- 

 quently in pairs, may form threads. 



Motility. — It is actively motile. 



Sporulation. — At about 30'' it forms bright, oval, median 

 spores. 



Anilin dyes. — React well. 



Growth. — Rapid. 



Oelatin plates. — The deep colonies form yellowish masses, whereas 

 the surface ones liquefy rapidly and then form grayish-brown, granu- 

 lar patches with flbrillated borders. 



Stab culture. — Slow liquefaction along the entire line of inoculation. 

 The gelatin becomes colored yellowish and on the surface a thin, 

 folded, grayish-white scum forms. The liquid remains cloudy for some 

 time, but later the growth settles to the bottom. 



Streak culture. — On agar, it forms a thick, grayish or yellow, sticky 

 covering. On potato, a light brown, transparent growth results which 

 sometimes becomes folded. 



Milk. — Without change in the amphoteric reaction the casein 

 gradually coagulates, as with rennet. Subsequently, after about 8 

 days, the casein is redissolved or peptonized with formation of pepton, 

 leucin, tyrosin, ammonia and bitter products. From hydrated milk 

 sugar and lactates it forms butyric acid. 



Oxygen requirements. — It is aerobic. 

 Temperature. — It can grow at the ordinary temperature, 

 but its optimum is at 35 to 40°. 



Behavior to gelatin. — -It liquefies gelatin. 

 Aerogenesis.— Butyric acid is formed. 

 Pathogenesis. — It has no effect on animals. 



A large number of aerobic and anaerobic bacteria give 



rise to butyric acid fermentation (see p. 103). The vibrion 



butyrique of Pasteur was the first anaerobe discovered (1861). 



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