Improvement of Missouri Herds. 



383 



A single drop of milk contains from one hundred million to one 

 hundred and fifty million fat globules. The size of the fat glob- 

 ules varies, first, with the breed and individuality of the animal, 

 and second, according to the length of time the animal has been in 

 milk. When a cow is fresh there is a smaller number of globules, 

 but the globules are larger. When the cow is well along in her 

 milking period the globules are smaller, but more numerous. The 

 fat is lighter than any other constituent of the milk. 



Casein — Average milk contains about 3 per cent, of casein, 

 which in fresh milk is practically in a soluble condition, but in sour 

 milk is precipitated as curd. The per cent, of casein in milk is 

 quite constant, ranging from 2.8 to 3.5. As a general rule normal 

 milk contains less casein than fat. 



Albumen — Average milk contains about one-half a per cent, 

 of albumen, which is nearly identical with egg albumen, or the white 

 of the egg. When fresh milk is boiled the "scum" which forms on 

 the surface is albumen. The amount of albumen in milk is quite 

 constant, and ranges from one-half to three-fourths of a per cent. 



Milk Sugar — Lactose, or milk sugar, is present in milk to the 

 extent of about 5 per cent. When obtained in the pure state it re- 

 sembles in appearance confectionary sugar, but not in taste. Milk 

 sugar takes an important part in butter and cheese-making, as it is 

 the material from which the acid is formed when milk sours. The 

 amount of milk sugar or lactose in milk is quite constant, ranging 

 from 4.6 to 5.4 per cent. In average milk it is the constituent 

 which is present in, largest amount of any of the milk solids. 



Ash — When the milk solids are burned there is a small amount 

 of greyish, white ash obtained. The ash content of milk is con- 

 stant and varies but little from three-fourths of one per cent. The 

 white substance, which settles at the bottom of the Babcock test 

 bottles when testing, is ash. 



AVERAGE MILK HAS ABOUT THE FOLLOWING COMPOSITION. 



Ave. per cent. 



Range per cent. 



Water 



Fat 



Milk sugar 

 Casein . . . . 

 Albumen. . 

 Ash 



87.00 

 3.50 

 5.00 

 3.25 

 0.50 

 0.75 



82.4 to 89.6 

 2.5 to 6.0 

 4.3to 6.0 

 2.5 to 4.0 

 0.5to 0.8 

 0.6to 0.8 



