Milk is not a beverage. It is a food. A quart of milk contains as much food and fuel value as eight eggs or twelve ounces of lean beef. That is, a cupful (one-half of a pint) is equal to two eggs or three ounces of lean beef. This shows that milk should not be taken to quench thirst, but to supply nourishment. Milk is one of our most satisfactory and economical albuminous foods, even at the present high prices. In many foods from 5 to 10 per cent of the protein goes to waste. In milk the waste does not ordinarily amount to more than about 1 per cent. This fluid generally leaves the stomach within one or one and one-half hours after being ingested.

In spite of its merits as a food some writers on dietetics advocate that adults stop using it, giving it only to the young.

Milk is an excellent food when properly used. When abused it tends to cause discomfort, disease and death, and so does every other food known to man. Milk is given in fevers and in other diseases, when the digestive and assimilative processes are suspended. This is a serious mistake and has caused untold numbers of deaths. When the digestion has gone on a strike all feeding is destructive. Milk and meat broths, which are generally given, are about the worst foods that could be selected under the circumstances, for they decay very easily, and are excellent food for the numerous bacteria that thrive in the digestive tract during disease. These foods must decay when they are not digested, for the internal temperature of the body during fevers is over one hundred degrees Fahrenheit.

When bacteria are present in excess they give off considerable poison, which makes the patient worse. If circumstances are such that it is necessary to feed during acute disease, which is always injurious to the patient, let the food be the least harmful obtainable, such as fruit juices. Even they do harm.

In our country cow's milk is used almost exclusively, and that is the variety that will be discussed in this chapter. In other lands the milk of the mare, the ass, the sheep, the goat and of other animals is used. Human milk is discussed in detail in the chapter on Infancy.

The objection voiced against cow's milk is that it is an unnatural food for man, only fit for the calf, which is equipped with several stomachs and is therefore able to digest the curds which are larger and tougher than the curds formed from human milk. It is said that the curds of cow's milk are so indigestible that the human stomach can not prepare them for entry into the blood. This is probably true, but it is also true of other protein-bearing foods. The digestion and assimilation of proteins are begun in the stomach and completed in the intestines, and the protein in milk is one of the most completely utilized of all proteins.

To call a food unnatural means nothing, for we can call nearly all foods unnatural and defend our position. A natural food is presumably a nutritious and digestible aliment that is produced in the locality where it is consumed, one that can be utilized without preparation or preservation. So we may say that a resident of New York should not use figs, dates, bananas and other products of tropical and semi-tropical climates, for they are not natural in the latitude of New York. We can take the position that it is unnatural for people to eat grains, which need much grinding, for the birds are the only living beings supplied with mills (gizzards). We can further say that it is unnatural to eat all cooked and baked foods. But such talk is not helpful. The more a person uses his brain the less power he has left for digestion and therefore it is necessary to prepare some of the foods so that they will be easy to digest. Man is such an adaptable creature that we are not sure what he subsisted on before he became civilized and are therefore unable to say what his natural food is. We know that in the tropics fruits play an important part in nourishing savages, while in the frozen north fat flesh is the chief food. Perhaps there is no natural food for man.

Some of those who advocate the disuse of milk have a substitute or imitation to take its place, nut milk made from finely ground nuts and water. Like all other imitations, it is inferior to the original. It is more difficult to digest than real milk and the flavor is quite different.

The objection that milk is indigestible is not borne out by the experience of those who give it under proper conditions. It is true that milk disagrees with a few, but so do such excellent foods as eggs, strawberries and Concord grapes, and many other aliments which are not difficult to digest. This is a matter of individual peculiarity. Some can take boiled milk, but are unable to take it fresh, and vice versa. Outside of the few exceptions, milk digests in a reasonable time and quite completely. It is easier to digest than the legumes (peas, beans, lentils) which are rich in protein. It is also easier to digest than nuts, which contain much protein. The milk sugar causes no trouble and cream is one of the easiest forms of fat to digest, if taken in moderation. The protein in milk will cause no inconvenience if the milk is eaten slowly, in proper combinations and not to excess. The rennet in the stomach curdles the casein. The hydrochloric acid and the pepsin in the gastric juice then begin to break down and dissolve the clots, and the process of digestion is completed in the small intestines.

Those who overeat of milk in combination with other foods will derive benefit from omitting the milk. They will also be benefitted if they continue using milk and omit either the starch or the meat. When foods disagree, in nearly every instance it is due to the fact that too much has been eaten and too many varieties partaken of at a meal. Some may single out the milk or the meat as the offenders. Others may point to the starches, and still others to the vegetables with their large amount of indigestible residue. They are all right and all wrong, for all the foods help to cause the trouble. However, such reasoning does not solve the problem. If the meals cause discomfort and disease, reduce the amount eaten, take fewer varieties at a meal and simplify the cooking. Those who eat simple meals and are moderate are not troubled with indigestion.