. 34 



BUT^rER iVEB CHEESE. 



]M I L K . 



The milk of cows is considered, by general consent, the most 

 congenial food for man. Investigations in regard to its proximate 

 constituents and their chemical composition, have taught us, proba- 

 bly more than anything else, what are the requisites of a really 

 good diet. The relative nutritive value of the long list of substan- 

 ces which make up our choice of articles of food, has frequently 

 been decided by a comparison of their chemical composition and 

 their physical condition with that of milk. A liberal use of 

 milk promises to benefit both the dealer and the consumer, and de- 

 serves hearty encouragement. It is of the utmost importance to 

 obtain it in a pure, normal condition. The main components of 

 milk are partly of an organic and partly of an inorganie character. 

 They consist of butter, casein (or cheesestuff), sugar of milk, the 

 phosphates of lime, magnesia and iron, the chlorides of potassium 

 and sodium, besides some soda in combination with casein. All 

 these compounds, with the exception of butter, are present in solu- 

 tion ; the latter substance is merely suspended in the liquid in 

 countless small globules, and causes the peculiar color and the 

 opacity of the milk. Each fat globule is surrounded by a very thin 

 cc^ting of a nitrogenous substance, which disappears soon after 

 exposure to air at a favorable temperature. A slight alkaline reac- 

 tion of the fresh, normal milk causes the solubility of the casein, 

 and the low specific gravity of the suspended fat globules favors 

 their rising to the surface, where they form cream. The milk from 

 a healthy cow always contains all the previously enumerated con- 

 stituents, yet in a somewhat varying proportion. The quantity of 

 milk w'hich can be obtained from a cow, and also the quality which 

 each individual cow of any particular bi'eed furnishes, dejjends, as 

 is well-known, on a number of circumstances, the most important 

 of which are, the constitution, the condition, and the age of the 

 {jjiimal, the amount and the kind of food, and the time and man- 

 nei of milking. I do not propose to treat on these important 



