Of the different constituents of milk, caseine is that which most resembles animal matter, and hence the intrinsic value of cheese as a nutritive article of food. Hence, also, the nutritive qualities of skimmed milk, or milk from which the cream only has been removed, while the milk is still sweet. The oily or fatty parts of milk furnish heat to the animal system; but this is easily supplied by other substances. From the peculiar nature of milk, and its extreme sensitiveness to external influences, the importance of the utmost care in its management must be apparent; and this care must begin from the moment when it leaves the udder, especially if it is to be made into butter. In this case it would be better, if it were convenient, to keep the different kinds of milk of the same milking by itself--that which comes first from the udder, and that which is drawn last; and if the first third could be set by itself, and the second and the third parts by themselves, the time required to raise the cream of each part would doubtless be considerably less than it is where the different elements of the milk are so intimately mixed together in the process of milking, after being once partially separated, as they are before they leave the udder. After milking, as little time as possible should elapse before the milk is brought to rest in the pan. The remarks of Dr. Anderson on the treatment of milk are pertinent in this connection. “If milk,” says he, “be put into a dish and allowed to stand until it throws up cream, the portion of cream rising first to the surface is richer in quality and equal in quantity to that which rises in a second equal space of time; and the cream which rises in a second interval of time is greater in quantity and richer in quality than that which rises in a third equal space of time. That of the third is greater than that of the fourth, and so of the rest; the cream that rises continuing progressively to decrease in quantity and quality, so long as any rises to the surface. “Thick milk always throws up a much smaller proportion of the cream which it actually contains than milk that is thinner, but the cream is of a richer quality; and if water be added to that thick milk, it will afford a considerably greater quantity of cream, and consequently more butter, than it would have done if allowed to remain pure; but its quality at the same time is greatly deteriorated. “Milk which is put into a bucket or other proper vessel, and carried in it to a considerable distance, so as to be much agitated and in part cooled before it be put into the milk-pans to settle for cream, never throws up so much or so rich a cream as if the same milk had been put into the milk-pans, without agitation, directly after it was milked.”