30 Mitk and Its Products. 
lymphatics for a longer time, which also would 
tend to make it poorer in fat. 
The food also has a considerable influence upon 
the quality of the milk, although the quantity of 
the milk is more easily affected by changes in the 
amount and character of the food than is quality. 
In fact, with cows kept under favorable conditions, 
with an abundant supply of food, it is hardly 
possible to increase the proportion of fat to other 
solids by a change in the food. On the other hand, 
while the amount of the various constituents of 
the milk is not easily affected by the food, the 
quality of the constituents themselves may be 
considerably influenced, notably in the case of the 
fat. Certain foods have a marked influence upon 
the character of the milk fat. Thus linseed meal, 
gluten meal and eertain other foods make a soft, 
oily fat, while cotton seed meal, the seeds of the 
various legumes and wheat bran make a hard fat. 
Constituents other than the fat are not so readily 
affected in this way. 
Of the constituents of milk, the ash and the 
sugar are the least variable, the fat and albumin 
the most variable, while the casein usually bears a 
nearly constant ratio to the fat. The percentage 
of water also varies considerably. The causes of 
the variation of the fat have already been noticed. 
The proportion of albumin is’ very largely in- 
fluenced by the physieal condition of the cow, and 
it has been shown, notably by Van Slyke (see 
Chapter X.), that with what may : k 
: : Digitized by Microsoft be called normal 
