188 BACTERIOLOGY 



in the same medium produces a nail-culture without lique- 

 faction. A wax-like layer appears on potato. 



Other pathogenic bacteria in milk. In the milk of 

 animals suffering from tuberculosis bacilli may be found, ac- 

 cording to Bollinger, even before the udders become diseased. 

 Typhoid bacilli may also find their way into milk along with 

 water, and may develop abundantly there. The bacteria of 

 cholera, too, are similarly capable of copious multiplication in 

 milk without perceptible alteration, but they are destroyed 

 when lactic acid fermentation sets in. In milk from a cow 

 suffering from inflamed udder, the Staphylococcus pyogenes 

 aureus has been detected by Kriiger. 



Saccharomyces ruber. Demme has found a yeast occur- 

 ring in milk and cheese which produces in the latter red 

 punctiform accumulations of pigment, and in the milk a red 

 sediment. This yeast he has described as Saccharomyces 

 ruber. Gelatine is not liquefied by it, and it develops on the 

 plate colonies of the size of a grain of millet-seed, which 

 show no red colour until a week has elapsed. In thrust- 

 cultures the growth is chiefly on the surface. Discs of 

 potato are covered with a coating of the colour of raspberries 

 in from eight to twelve days. 



Bacillus Caucasicus (Dispora Caucasica, or Kephir bacillus). 

 The name of kephir grains is given to maeses of micro- 

 organisms in a zooglcea, which are used in the Caucasian 

 districts for the preparation of the drink known as ' kephir ' 

 from milk. In this process the caseine passes into solu- 

 tion, while the milk-sugar is affected after the manner of 

 a lactic acid and alcohol fermentation (Adametz). The 

 granules contain yeast and bacteria capable of peptonising 

 caseine, viz. the Bacillus acidi lactici, Bacillus butyricu*, 

 Bacillus subtilis, and in addition to these a micro-organism 

 to which Kern ascribes the principal role, and which bears 

 the name Bacillus caucasicus. This consists of short 



