Bacillus Violaceus. 



B. VIOLACEUS BEROLINENSIS. VIOLET BACILLUS OF WATER. 



Origin. — Water of the river Spree at Berlin, and of the 

 Thames at London; also in well water. 



Form. — A slender rod about two to three times as long 

 as wide; it forms threads, but is usually in pairs. 



Motility. — It is actively motile. 



Spokulation. — Forms median spores. 



Anilin dyes. — React readily. 



Growth. — This is moderately rapid. 



Gelatin plates. — The colony is irregular with loose fibrillated bor- 

 der. The center shows quite early a violet color. It liquefies. 



Stab culture. — Funnel-shaped liquefaction along the entire line of 

 inoculation. A violet sediment collects on the bottom, while the 

 liquefied gelatin above is perfectly clear. A violet ring may adhere 

 to the wall of the tube on the surface of the liquid. 



Streak culture. — On agar, it forms a smooth, thin, moist, bright vio- 

 let covering. On potato, the growth is somewhat slow but very char- 

 acteristic, forming a bright violet, eventually dark covering. On 

 blood-serum, a violet color forms and liquefaction takes place. 



Oxygen requirements. — It is a facultative anaerobe. 

 Oxyg-en is necessary to pigment formation. 



Temperature. — It does not grow at higher temperatures. 



Behavior to gelatin. — Liquefies. 



Pigment production. — This depends upon the presence 

 of oxygen. The color is soluble in alcohol, insoluble in 

 ether and in chloroform. It is changed to a green by min- 

 eral acids. 



Pathogenesis.^ — It has no effect. 



About ten additional violet or blue pigment producing 



bacilli are known. Some of these, however, may be mere 



varieties. 



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