Composition of Milk and Its Products. 11 



nine per cent, of solids not fat, and three per cent, of 

 fat, the milk serum will make up 97 per cent, of the 



milk, and the serum solids, — _ - = 9.28 per cent, of 

 the milk serum. 



1 6. Water. The amount of water contained in cow's 

 milk ranges from 82 to 90 per cent. Normal cow's milk 

 will not, as a rule, contain more than 88 per cent, of 

 water, nor less than 84 per cent. In states where there 

 are laws regulating the sale of milk, as is the case in 

 twenty-two states of the Union (see Appendix, Table 

 II), the maximum limit for water in milk in all instances 

 but one (South Carolina) is 88 per cent.; the state men- 

 tioned allows 88.5 per cent, of water in milk offered 

 for sale within her borders. The effect of fraudulently 

 increasing the water content of milk by watering is con- 

 sidered under Adulteration of Milk (121). 



17. Fat. The fat in milk is not in solution, but sus- 

 pended as very minute globules, which form an emul- 

 sion with the milk serum; the globules are present in 

 immense numbers, viz., on the average about one hun- 

 dred millions in a single drop of milk ; a quart of milk 

 will contain about two thoiisand billions of fat globules, 

 a number written with thirteen figures. The sizes of 

 the globules in the milk from the same cows vary ac- 

 cording to the stage of the period of lactation, the glob- 

 ules being largest at the beginning of the lactation 

 period, and gradually decreasing in size with its prog- 

 ress. Different breeds of cows have fat globules of 

 different average sizes; the Channel Island cows are 

 thus noted for the relatively large fat globules of their 



