20 BUTTER-MAKING AND COMPOSITION OF MILK 



stituents upon the properties of milk, it is one of the most impor- 

 tant components of the milk. It exists partly in solution, and 

 partly in suspension. Babcock maintains that about one-third 

 of the usual ash constituents are in suspension, and that they 

 consist chiefly of lime phosphate. 



All of the minerals in milk consist chiefly of potash, lime, 

 soda, magnesia, and iron, combined with phosphoric, hydro- 

 chloric, sulphuric, and carbonic acid. Calcium phosphate 

 constitutes about one-half of all the ash constituents. They 

 are named above, in order, according to the extent to which 

 they occur in milk. 



Gases of Milk. These do not normally exist in milk to such 

 an extent as to enable chemists to determine them quantita- 

 tively, but they are of great importance, owing to the effect they 

 have upon the quality of the milk, viewed in the commercial 

 sense. 



Gases in milk may be divided into two classes according to 

 their origin; namely, (i) those imparted to milk before milking 

 and (2) those which are later formed and absorbed in milk. 



(i) When freshly drawn, milk has a characteristic odor, 

 which seems to be normal to all fresh milk. The gases which 

 cause this odor are very volatile, and by cooling and stirring the 

 milk can, to a large extent, be eliminated. The amount and 

 kind of taints existing in milk, immediately after it has been 

 drawn, largely depend upon the food which the cow has been 

 fed. Turnips, onions, and garlic, when fed to cows a short time 

 before milking, cause undesirable gases or taints to exist in the 

 milk. Good hay, bran, and good grass produce milk of superior 

 quality, containing no odors excepting those which are natural to 

 all milk when first drawn. 



The milk yielded by cows pasturing in the Alps of Switzer- 

 land is said by tourists to possess a peculiar, not undesirable, 

 spicy odor and flavor. It is maintained by the native people in 

 Switzerland that the peculiar flavor of the Emmenthaler cheese 

 cannot be developed anywhere else in the world. This flavor 

 they believe to be due to the kind of vegetation the cows feed 

 upon in the Alpine pastures. In Denmark, the poor people 



