118 , BACTERIOLOaY 



water. The Bacillus liodermos grows with especial luxuri- 

 ance in milk. 



Bacillus melochloros. — The Bacillus melochloros was origi- 

 nally discovered in the author's Institute by F. Winkler 

 and Von Schlatter, in the caterjDillars' excreta found in 

 worm-eaten apples. It is at times a constant inhabitant 

 of the air of the author's laboratory, and often appears as 

 a guest upon cultures of other micro-organisms ; and it is 

 possibly identical with the Bacillus hutyri ftuorescens, found 

 by Lafar in butter. It consists of slender, fairly long rods, 

 with smoothly rounded ends and actively motile, and is 

 distinguished by its unusually rapid growth, so rapid that 

 even in four hours there appear on the plate greyish-white 

 colonies, in which darker and more closely-packed masses 

 are to be seen ; while as early as the second day the gela- 

 tine is liquefied with development of a greenish-yellow 

 colour. In thrust-cultures also, on the second day, an 

 hourglass-shaped depression shows itself, around which 

 there is very rapid liquefaction (fig. 42). The speedy 

 growth and greenish-yellow colour are also seen in super- 

 ficial cultures on agar, the surface of which very soon 

 becomes overspread with a thick yellowish coating, while 

 all the rest of the medium acquires a green tinge. On 

 plovers' egg albumen it grows with a splendid emerald 

 green colour, and on potato it forms a dirty reddish-yellow 

 layer. The pigment developed by the Bacillus melochloros 

 is very readily soluble in water, but not at all in alcohol or 

 chloroform. It is destroyed by acids, but restored again by 

 alkalies. Older cultures acquire an exceedinglj' unpleasant 

 odour. When the pure culture is injected into the veins or 

 peritoneal cavity of rabbits the animals perish in a week at 

 furthest. 



Bacillus multipediculosus, which was discovered by Pliigge, 

 shows small thin immotile rods. The colonies on a gela- 



