Milk is a typical or perfect food. By this we mean it contains all the necessary elements to sustain life and build and repair the tissues of the young mammalia during the period of rapid growth. It is especially suited to the aged, invalids and diet for the sick. Milk is a food, not a beverage, and must not be taken as a beverage with heavy meals of meat and vegetables. It is not a desirable food for active adults, and when swallowed rapidly like water, produces discomfort and frequently indigestion.

All foods, liquid, semi-solid and solid, should be masticated sufficiently long to be mingled with the mouth secretions. The carbohydrate of milk is lactose or milk sugar, not so sweet as cane sugar, and less liable to fermentation. Milk for the well and for the sick must be perfectly sweet, clean, and should be kept in a cold place, in covered bottles. If left open in the refrigerator, it absorbs odors and flavors of other foods. It may be used warm, hot or cold, according to the physician's orders, but should not in any case be iced.