‘144 Milk and Its Products 
organs regain their tone. Disorders of this sort 
are especially likely to occur when cows that have 
been poorly fed during the winter are suddenly turned 
on fresh rank pasture in the spring. 
Quality of milk for consumption.—The fat is the 
most variable and the most valuable constituent of 
the milk, so that milk is ordinarily considered to be 
of value for human food in proportion to the amount 
of fat it contains, but where it is to be used as 
a food in large quantities, the fat may frequently 
be present in too large quantities for the digestion 
of many persons. Milk containing about 4 per 
cent of fat is probably an ideal food for the gen- 
eral mass of human beings. If there is above 5 
per cent of fat the other solids are somewhat out 
of proportion, and many are likely to have trouble 
with their digestion from using. large amounts of 
such milk. On the other hand, if there is less 
than 3 per cent of fat, the casein and other solids 
are in too great proportion to the fat, and are less 
readily digested. The question of the healthfulness 
ot milk from which a large part of the fat has been 
removed is one frequently discussed. The removal of 
the fat does not thereby in any way injure the other 
solids; they are still there, and still as useful for 
food as before the fat was removed, only in con- 
suming such milk as food the fat must be supplied 
in some other way. For the person of vigorous 
digestion, who for reasons of economy desires to 
supply the fat required by his system in some 
cheaper form than that of milk fat, skimmed milk is 
