Milk varies widely in composition, depending 

 Chemical upon the breed and individuality of the cow, 



Composition of stage of lactation and weather conditions. 

 Milk. Food, as a rule, has little elTect in permanently 



changing the proportions of the several in- 

 gredients. One hundred pounds of milk of good average quality 

 should contain about the following amounts of the different con- 

 stituents :' 



Pounds in loo or Per Cent. 



Water, ....... 87.00 



Fat, . 



Albuminoids 



Milk sugar, 

 Ash, . 



^ Casein, 

 i Albumin, 



4.00 

 3.00 



•50 



4.80 



.70 



100.00 

 The total solids include all of the ingredients excepting the water. 

 The proportions may be expressed by the following squares': 



Water Sugar Fat Casein Ash 



and Albumin 



For ordinary purposes, the chemist determines only the total solids 

 and the fat, and obtains the solids not fat by difference. The fol- 

 lowing figures, according to Hucho^ and Koenig^ give the approxi- 

 mate average composition of the milk of different breeds : 



•The average composition of 793 samples of milk from pure bred and grade cows accord- 

 ing to Koenig is 12. 8Ji^ solids and 3. 6t/t of fat ; of 2oo,oao samples of mixed milk analyzed 

 by the Aylesbury Dairy Co., London, (See Richmond) is 12.90':; solids and 3.90:* fat Wiley 

 says recent analyses of average milk show 12.90'! solids and 454 fat. The average of 4103 

 samples made at this Station (Jersey blood predominating) is 13.63^ solids and 4.43^ fat. 



2 See Farmers' Bulletin No. 42, U. S. Dept. of Agriculture. 



3 WoU's Handbook, p. 213 and 214. 



