BACILLUS CYANOGENUS. 361 



Bacillus janthinus (Zopf). 

 (Bacterium janthimun, violet bacillus.) 



Zopf observed on pieces of swine's bladder, which Violet 

 were floating on water containing fungi, violet patches 

 consisting of longer and shorter mobile rods, ultimately 

 breaking up into short segments. These bacilli are 

 perhaps the same as those found by Hueppe, and at a 

 later period on several occasions in the laboratory at 

 Gottingen, and which produce an intensely bluish-violet 

 pigment. These bacilli when grown on gelatine form at 

 first milk-white layers, which gradually assume a violet 

 colour at the margins, and in the neighbourhood of which 

 the gelatine acquires the same tint ; it is not till after 

 several days that the whole surface of the colonies acquires 

 an intense violet hue. In puncture cultivations the 

 violet growth only develops at the surface ; on potatoes 

 a deep violet layer is produced. In sterilised milk the 

 bacilli produce patches on the cream, at first intense 

 sky-blue in colour, but gradually becoming blackish- 

 blue ; at the same time the casein is precipitated and 

 then peptonised, the fluid acquiring an alkaline reaction, 

 and ammonia being formed (Hueppe). 



Bacillus cyanogenvs. 

 (Bacterium syncyanum, Bacillus of blue milk.) 



The occurrence of blue milk is frequently observed in Bacillus of 

 many places ; at, times its occurrence varies, like that of bluemilk - 

 epidemics, in accordance with local and seasonal influences. 

 Great moisture of the atmosphere has generally been 

 regarded as a favouring factor, while temperature, light, 

 &c., do not apparently exercise any marked influence. 



Fuchs in 1841 asserted that a vibrio was the agent Former 

 which produces the blue colour, and he demonstrated 

 that this production of colour could be set up in good 

 milk ; these investigations were confirmed and extended 

 by Haubner, Hermbstadt, Hosier, and others, and recently 

 more especially by Neelsen and Hueppe. Neelsen has 



