VARIATION OF FAT IN MILK. 69 
conditions the cows are milked in the morning about 5 o’clock, 
and in the evening about 7 o’clock. This is especially true 
during the spring and early summer months. This long interval 
during the day causes the cow to give a greater quantity of 
milk in the evening, but it contains a smaller per cent of fat. 
The recent results obtained by Ingle illustrate this point very 
plainly. Five cows were milked at 6 a.m. and at 3 P.M. during 
Fic. 15.—The wrong way to milk cows. (From Glucose Sugar Refming 
Catalogue.) 
a period of three weeks. The average fat-content of the eve- 
ning’s milk was 4.26% and of the morning’s milk 2.87%. 
During the four weeks following the same cows were milked 
at 5.30 a.m. and 5 p.m. The fat-content of the evening’s milk 
was 3.80%, and of the morning’s milk 3.18%. It is main- 
tained, and the above results indicate the same, that even 
if the intervals between milkings are equal, the morning’s 
milk will contain slightly less fat. This is accounted for by 
the theory that the fat-secreting cells are more active during 
the day, when the cow is exercising. 
