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, 7.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. 
