Kefir and Kumiss 



379 



Fig. 60. Kefir grains, and microorganisms of kefir. 

 (After Freudenreich.) 



wards, when softened, they are placed in a small quan- 

 tity of milk. The milk is occasionally stirred, poured 

 into bottles at the 

 end of twenty-four 

 hours, and in two 

 or three days is 

 ready for use. The 

 kefir thus prepared 

 has a pleasant acid 

 taste and contains, 

 also, small quan- 

 tities of alcohol. 



Microscopical examination shows the kefir grains to 

 consist of yeasts and bacteria. There is in them, besides 

 ordinary beer yeast, a bacterial species at one time 

 called Diaspora caucasica. It is thought that the yeast 

 found in kefir is not capable of fermenting the milk- 

 sugar directly, but that the alcohol is made by it out of 

 the milk-sugar, with the aid of the lactic-acid bacteria. 

 We must conclude, therefore, that the microorganisms 

 of the kefir grains represent another instance of associ- 

 ative action. 



Kumiss. — Kumiss is another milk beverage very 

 popular among the Mongolian peoples of Siberia and 

 Central Asia. It is prepared by the addition of yeast to 

 mare's or camel's milk kept in wooden vessels. Both 

 lactic acid and alcohol are formed in the milk, the bever- 

 age being ready for consumption in two or three days. 

 The exact nature of the changes occurring in the making 

 of kumiss is not known. It is likely, however, that, as 

 in the case of kefir, lactic-acid bacteria are prominent. 



