608 



VITAL ACTIONS OF THE LOWER FUNGI. 



Chemical 

 composition 

 of kephyr. 



one part is added to three or four parts of fresh cow milk, it 

 is then introduced into flasks and allowed to stand for about 

 forty-eight hours, being shaken from time to time. Of the 

 drink so prepared, from one-fifth to one-third is left behind 

 in the flask, as a ferment for new milk which is added to it. 

 The temperature must, as a rule, be about 18 C. ; it is only 

 at the commencement that a higher temperature is desirable. 

 The kephyr granules which are being employed must be 

 cleansed carefully from time to time, and broken down till 

 they are about the size of a pea. The cleansed granules can 

 then be dried on blotting paper in the sun or in the neighbour- 

 hood of an oven ; in the dry state they retain their power of 

 growth for a very long time for several months, and even 

 years. 



The chemical investigations have as yet added as little 

 knowledge as to the course of the kephyr fermentation 

 as have the cultivation experiments. It is certain that the 

 most important products of fermentation are sethylic alcohol, 

 lactic acid, and carbonic acid ; small quantities of glycerine, 

 succinic acid, acetic acid, and butyric acid are also formed. 

 The amount of lactic acid in prepared kephyr is usually about 

 1*5 per cent. ; the amount of alcohol 1 Tr. ; both have been 

 shown to arise only from the milk-sugar. During the first 

 twenty-four hours the greater proportion of the milk-sugar is 

 utilised for the formation of lactic acid, while during the 

 following days the formation of alcohol is greater. When 

 the temperature is high (25 to 30 C.) the lactic fermentation 

 is too greatly favoured as compared with the alcoholic fer- 

 mentation, and it is only at a definite low temperature that the 

 two fermentations follow a normal course. The amount of 

 albumen in the milk is, according to the analyses as yet made, 

 apparently not altered in the kephyr fermentation ; but the 

 casein undergoes an alteration in that it becomes suspended in 

 the milk in extremely fine flakes, so that the whole fluid 

 assumes an almost cream-like consistence. It is probable that 

 the dietetic value of the preparation is largely due to this 

 alteration in form of the casein. Peptone cannot be demon- 

 strated. 



(6 1 ). Putrefaction. 



Putrefaction. Under the term putrefaction, or putrefactive fermenta- 

 tion, we understand the rapid and intense decomposition 

 of nitrogenous and chiefly albuminoid substances by 

 certain bacteria in which gaseous, foul-smelling products 

 are formed in large quantities. 



