Professor Boedeker has analyzed the milk of a healthy cow at various times of the day, with the view of determining the changes in the relative amount of its constituents. He found the solids of the evening milk (13 per cent) exceeding those of the morning's milk (10 per cent), while the water contained in the fluid was diminished from 89 per cent to 36 per cent. The fatty matters gradually increase as the day progresses. In the morning they amount to 2.17 per cent, at noon 2.63 per cent, and in the evening 5.42 per cent. This fact is important in a practical point of view ; for while sixteen ounces of morning's milk will yield nearly half an ounce of butter, about double this quantity can be obtained from the evening's milk. The casein is also increased in the evening's milk from 2.24 to 2.70 per cent ; but the albumen is diminished from 0.44 per cent to 0.31 per cent. Sugar is least abundant at midnight (4.19 per cent) and most plenty at noon (4.72 per cent). The per centage of the salts undergoes almost no change at any time of the day.—Edinburgh Medical Review.