326 APPLIED BACTEKIOLOGY 



four hours. Weigmann has discovered the cause of this 

 soapy taste to be due to an organism, which he also found 

 in the straw used as htter, from which it appears that the 

 milk becomes infected when the litter is changed at milking- 

 time. 



Milk is also liable to a number of other obscure changes 

 and diseases, the cause of which may be traced to bacterial 

 agency. Micro-organisms also play a useful part in con- 

 nection with dairy products, various organisms being 

 employed to bring about required changes in the milk. 

 Green mould {Penicillium glaucum) is the chief agent 

 employed in the ripening of Eoquefort and Gorgonzola 

 cheese. Moulds also play an important part in the pro- 

 duction of Brie and other soft cheeses ; the growth of certain 

 organisms is encouraged upon the surface of these cheeses, 

 so that the special ferment which they produce can pene- 

 trate the body of the cheese and bring about certain 

 characteristic changes. A certain yeast is used in the 

 production of kephir (the national drink of the Caucasus), 

 which is made by the fermentation of cows' milk, similar 

 to koumiss, which is produced by the fermentation of mare's 

 milk. White mould (Oidium lactis) is very frequently met 

 with in milk and other dairy products. When the milk 

 becomes sour, a white thick skin is found on the surface, 

 which is wholly formed of the mycelia and hyphae of this 

 mould. 



In the report of a special analytical and biological com- 

 mission on milk-supply, held under the auspices of the 

 British Medical Journal (1895), the following reforms were 

 suggested for the better management of dairies, to secure 

 a pure milk-supply : 



1. That all milking be carried on in the open air, the 

 animals and operators standing on a material which is 

 capable of being thoroughly washed, such as a floor of 



