NON-PATHOGENIC BACTERIA 97 



Colonies. Plate. Small yellow points which soon run 

 together, becoming indistinguishable. 



Stab-culture. A small yellow skin forms on the surface with 

 delicate wrinkles; cloudy masses in the liquefied portion. 



Staining. With ordinary stains. 



Bacillus Amylobacter (Van Tiegham) ; synonyms Clos- 

 tridium Butyricum (Prazmowsky) ; Vibrion Butyrique of 

 Pasteur (Fig. 51). Origin. Found in putrefying plant-infu- 

 sions, in fossils, and conifera of the coal period. 



Form. Large, thick rods, with rounded ends, often found in 

 chains. A large glancing spore at one end, the bacillus becom- 

 ing spindle-shaped in order to allow the spore to grow; hence 

 the name, clostridium. 



Properties. Very motile; gases arise 

 with butyric smell. In solutions of sugars, 

 lactates, and cellulose-containing plants 

 and vegetables, it gives rise to decomposi- 

 tions in which butyric acid is often formed. 

 Casein is also dissolved. 



Like granulose, a watery solution of 

 iodin will color blue some portions of the 

 bacillus; therefore it has been called amy- 

 lobacter. 



Growth. It is strongly anaerobic, and 

 has not yet been satisfactorily cultivated. Fig. 51. Bacillus 



Bacillus Lactis Cyanogenus (Bac- 

 terium Syncyanum) (Huppe) . Origin. Found in blue milk. 



Form. Small narrow rods about three times longer than they 

 are broad; usually found in pairs. The ends are rounded. 



Properties. They are very motile; do not liquefy gelatin; 

 form spores usually in one end. A bluish-gray pigment is 

 formed outside of the cell, around the medium. The less 

 alkaline the media, the deeper the color. It does not act upon 

 the milk otherwise than to color it blue. 



Growth. Grows rapidly, requiring oxygen. Colonies on 

 plate. Depressed center, surrounded by ring of porcelain-like 

 bluish growth. Dark-brown appearance under microscope. 

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