Curves are produced to show the proportions between morning and evening yield of milk, yield of fat, and fat per cent, in the case of individual cows milked alternatively at 6 a.m. and 9 p.m. and again at 6·30 a.m. and 3·30 p.m. In each case the intervals between milkings were 15 and 9 hours.

It is seen that when the 15-hour interval is between night and morning milkings as specified, a bigger proportion of milk is produced at the morning milking than is produced at night when the same interval is between morning and night milkings. The curves and Tables I and II show that this is quite clearly the case with the six cows in the trial.

It is apparent that, as far as winter conditions are concerned, night itself, or factors operating at night tend to high milk production of low fat content.