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cent, of water. In South Carolina the law fixes the maximum 

 limit of water in milk at 88.5 per cent.; Minnesota, Massachu- 

 setts and New Hampshire, at 87 per cent.; five other states, at 

 87.5 per cent., and eight othep states, at 88 per cent. The city 

 of Montgomery fixes the maximum limit at 87.5 per cent. It 

 is obvious that a high percentage of water means a poor milk 

 and a low pei-centage of water means a rich milk, provided 

 there are no solid adulterants added to the milk. 



The fat in milk is in the form of an emulsion in the milk 

 serum. An enormous number of fat globules are suspended 

 in the milk serum. The size of the fat globules may vary 

 slightly in the different breeds of cattle. One drop of milk 

 may contain 100,000,000 fat globules. Chemically speaking, 

 milk fat is a compound of fatty acids and glycerine. About 

 ^2 per cent, of pure milk fat is a mixture of glycerine and 

 insoluble fatty acids (palmitic, stearic and oleic acids), and 

 about 8 per cent, of milk fat is made up of glycerides of vola- 

 tile fatty acids (butyric, caprylic and caproic acids). The 

 glycerides of the volatile acids of milk fat are very unstable; 

 they give the flavor and aroma to butter and serve to distin- 

 guish genuine from artificial butter. When the glycerides of 

 these volatile fatty acids are decomposed by bacteria or light, 

 the volatile acids are set free and they produce the unpleasant 

 odor in rancid butter. 



The fat in cow's milk ranges from 3 to 6 per cent.; the 

 average is about 4 per cent. As a rule if the fat in a cow's 

 milk falls below 3 per cent, she does not pay for her feed. 

 The mixed milk from a dairy herd should not fall below 3 per 

 cent, in fat contents, and, except in unusually rich milk, it will 

 not exceed 5 per cent. The minimum legal standard for most 

 of the states is 3 per cent.; Georgia and Minnesota require 

 milk to contain 3.5 per cent, of butter fat; Rhode Island places 

 the minimum limit at 2.5 per cent. The city of Montgomery 

 requires milk to contain 3 per cent, of butter fat, and the 

 limit should be raised to 3.5 per cent. 



Milk-su^ar or lactose is very similar in chemical compo- 

 sition to cane sugar, but it is not nearly so sweet and is less 

 soluble in water. Normal cow's milk contains from 4 to 6 



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