184 BACTERIOLOGY 



elements endowed with rapid automatic motion. On the 

 gelatine plate small punctiform colonies occur, which liquefy 

 the gelatine and acquire a yellow colour. They resemble 

 at first a culture of the cholera vibrio, but are distinguished 

 from it by the speedier liquefaction of the gelatine, and by 

 the yellowish tint of the colonies. Liquefaction is, however, 

 slower than in the case of the Vihiio proteus. In thrust- 

 cultures the gelatine is liquefied along the whole length of 

 the inoculated track, and in a few days the bacteria sink to 

 the bottom and lie there in a loose coil. The bubble of air 

 in the upper part is larger than in cholera cultivations (see 

 fig. 53). A thin yellowish coating appears upon agar, a 

 yellowish film upon potato, and serum and plovers'-egg 

 albumen are liquefied. If injections of the cultures be made 

 into the intestinal canal of guinea-pigs, with the precautions 

 specified by Koch in the case of cholera bacilli, the animals 

 are destroyed. 



Bacillus lactis viscosus. — This very wide-spread spoiler of 

 milk was first found by Adametz in the water of brooks in 

 the neighbourhood of Vienna. It forms short rodlets re- 

 sembling cocci, which possess a thick, highly-refractive 

 capsule. On gelatine plates round disc-like colonies occur, 

 sometimes with concentric rings, and on them there forms 

 at a favourable temperature (16° to 20° C.) a broad, irregularly 

 serrated hem of a transparent, horny appearance. Surface- 

 cultures upon agar show narrow whitish stripes, the border 

 of which is at first smooth, but later finely serrated. 

 Sterilised milk becomes in four to six weeks viscous like 

 honey, so that it can be drawn out into long strings (slimy 

 fermentation) ; in milk which has not been sterilised the 

 cream alone becomes stringy or slimy, and such cream 

 yields a white, greasy butter which becomes quickly spoilt 

 owing to the presence in copious numbers of the butyric 

 acid bacillus, from which fact Adametz concludes that this 



