'227 



smill quantities among tlie normal mineral milk constituents." 

 The average amount of total ash in cows' milk is about .7 per 

 cent. The mineral constituents of milk are least liable to var- 

 iation. 



Clostrum or the first milk is that which is secreted imme- 

 diately after the birth of the calf. It contains a large per- 

 centage of albumen and ash, and a small amount of milk sugar. 

 It is thick, yellow, and coagulates when boiled. The first 

 milk is said to be nature's purgative to remove the meconium 

 from the alimentary canal of the offspring. In four or five 

 days the clostrum is no longer secreted and the milk becomes 

 normal. 



Milk is slightly heavier than water; its specific gravity 

 ranges from 1.029 to 1.034 at 60 degrees F. The variation in 

 the specific gravity is due to the variations in the relative 

 quantities of water and the solids in the milk. Milk that is 

 rich in fat will usually have a low specific gravity, because the 

 fat is lighter than water. If, however, the fat be removed 

 the specific gravity will be raised; skim milk ranges from 

 1.033 to 1.037. The addition of water to milk, or the leraoval 

 of fat from milk, are the two most common methods of fraud- 

 ulently changing the composition, specific gravity and value 

 of milk. 



Variations in the composition of normal or pure cow's 

 milk are due to the variations in the breed, individuality of 

 the cow, to the methods of feeding and handling, and to the 

 length of time since the cow became fresh. It is a matter of 

 common observation that certain breeds give richer milk than 

 others, while some breeds may give large quantities nf rela- 

 tively poor milk. Ditterent cows of the same breed will vary 

 to some extent in the quality and quantity of their milk. A 

 well balanced ration given in sufficient quantity will cause a 

 cow to yield milk to her greatest capacity. The breed, the 

 individuality of the cow, and the length of time since calving 

 will also have a direct influence upon the quantity; but the 

 (quantity of milk may be most quickly and easily changed by 

 changing the feed and the method of handling the cow. How- 

 ever, the richness of the milk or the proportion of fats and 



