MILK 23 



vidual milk, because the different variations in the milk 

 of individual cows balance one another more or less. 

 Under certain conditions, milk from different herds, i.e., 

 herd milk,, may show a greater variation in composition 

 than the mixed milk of several herds. For example, milk 

 from a Jersey or Guernsey herd will usually show a 

 higher fat content than milk from a Holstein or Ayr- 

 shire herd. The presence of a large proportion of "fresh" 

 cows in a herd at one time may cause the mixed milk 

 of the herd to be low in solids, especially fat, while a 

 large proportion of "strippers" may have the opposite 

 effect. The per cent, of fat in market milk may range 

 from 3 to 5 per cent., and the per cent, of solids not 

 fat from 8.5 to 10.5 per cent. The average composition, 

 as reported by Flieschmann, is : fat, 3.4 per cent. ; lactose, 

 4.6 per cent.; casein, 3 per cent.; albumin, 0.5 per cent.; 

 globulin, a trace; salts, 0.75 per cent.; water, 87.75 per 

 cent. 



Over 5000 samples of milk examined at the New 

 York State Experiment Station at Geneva, N. Y., were 

 found to contain an average of 3.9 per cent, of fat, 

 5.1 per cent, of lactose, 2.5 per cent, of casein, 0.7 per 

 cent, of albumin, 0.7 per cent, of salts, and 87.1 per cent, 

 of water. 



Although it is unusual, normal market milk may fall 

 below the usual limit for solids, especially fat, particu- 

 larly milk from a single herd, under some of the condi- 

 tions mentioned above. For this reason, difficulty has 

 at times been experienced in legally proving that milk 

 has been skimmed or diluted with skimmed milk or water, 

 and this has led to the adoption of legal standards for 

 milk and other dairy products by different states, the 

 United States government, and some municipalities. 



