THE EARTH'S BOUNTY 



ferent constituents: 87 pounds of water, 4 

 pounds of fat, 5 pounds of milk sugar, 3.3 

 pounds of casein and albumen, and 0.7 pound 

 of mineral matter or salts. 



But the quantities of the constituents vary 5 

 between wide limits. The total solids of milk, 

 meaning all the constituents except water, 

 may be as low as 10, or as high as 18 parts in 

 100. This variation is due to several causes. 

 The fat varies in quantity more than any other 

 part of the milk, running as low as about 2^4 

 parts in 100, and as high as 8; the larger the 

 proportion of fat, the richer the milk is said 

 to be. Most of the States, and many cities, 

 have a legal standard for the composition of 

 milk, and any milk falling below this stand- 

 ard is legally regarded as adulterated, al- 

 though it may be, in fact, the natural prod- 

 uct. The laws usually require 3, or 3Vz per 

 cent, of fat, 9, or O 1 /^ per cent, of " solids not 

 fat." (This term is commonly used to desig- 

 nate all the solid substances of milk other 

 than fat.) The total solids required thus 



179 



