BACTERIA. 83 



occurs in smaller colonies than a, and, in contrast with the 

 latter, grows well at higher temperatures, and forms more acid 

 than a, but does not coagulate milk. If this species is trans- 

 ferred, together with the kephir-yeast, to milk-sugar broth, the 

 fermentation is more vigorous than if the bacteria alone are 

 inoculated ; FREUDENREICH therefore presumes that Streptoccus 

 b splits up the milk-sugar, and that the fermentation of the 

 latter is rendered possible by this previous decomposition. 

 The kephir-yeast discovered by him shows a remarkably 

 strong growth and a weak fermentation in beer- wort, but does 

 not appear to produce any fermentation in milk or milk-sugar 

 broth. The growth consists of oval cells (3-5 /x long, 2-3 //, 

 broad) ; it forms neither a film nor spores ; the optimum 

 temperature of this species lies at 22 C. 



In the course of his experiments, FREUDENREICH succeeded 

 in producing a liquor resembling kephir, for which purpose he 

 inoculated a mixture of the four species, detailed above, in 

 milk, and, after a lapse of some days, introduced a small 

 portion of this sour, coagulated milk, which had been re- 

 peatedly shaken, into sterilised milk ; he therefore concludes 

 that these four species, through their symbiosis, are able to 

 bring about the kephir-fermentation. He could not observe 

 any synthesis of kephir-grains by means of the four species, 

 and it is not yet clear what part Dispora Caucasica plays in 

 the whole process ; moreover, it appears to be highly probable 

 that species of bacteria, other than the two coccus-forms 

 described by FREUDENREICH, in addition to other budding 

 fungi, are active in the process. It may be deserving of 

 special notice that in the author's laboratory it has been 

 proved that in Eussian kephir-grains a genuine Saccharo- 

 myces occurs which ferments milk-sugar independently, whereas 

 all previous investigators only found budding fungi incapable 

 of spore formation. 



In some parts of North America a ferment resembling 

 kephir- grains is used in the fermentation of saccharine liquids. 

 According to Mix' researches it contains a yeast-species which 

 agrees with the one described by BELJERINCK and also a 

 Bacterium which resembles KERN'S Dispora. 



If one of the kephir-grains is allowed to remain in milk, it 



