CHAPTER IY. 



MILK. 



Composition The Dairy The Taste of Milk Adulteration. 



The Composition of Milk Milk is essentially an 

 emulsion of oily matters in a water containing albumen 

 and casein (cheese) and a sugar in solution. Its oil floats 

 in it in the form of globules, varying from -aoVo th to T-oW^h 

 part of an inch in diameter. If the milk be kept at rest, 

 these globules will rise to its surface and form a coating of 

 oream in which, along with still a portion of water holding 

 various substances in solution, they form a fluid which 

 upon being violently agitated, thus rupturing the globules 

 and enabling them to unite, separates into the butter 

 which these form, and the " butter-milk," containing 

 water, casein, sugar, &c., which they leave behind. The 

 composition of milk, in so far as these buttery globules are 

 concerned, is ascertained in a rough way by an instrument 

 called a lactometer or lactoscope. In one form it consists 

 of a glass tube five inches long, held upright in a frame 

 and graduated downwards in a scale dividing the contents 

 below the zero mark into 100 parts. On being filled up 

 to the zero mark and left at rest the mechanical separation 

 of the buttery globules (cream) takes place, and the 

 quantity of this cream in lOOths of the whole quantity of 



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