Part 4

Of course, while digestion and mental and muscular activity are at their height, the body temperature is highest. These activities usually reach a maximum in the afternoon and the temperature is then highest, while, as a rule, it decreases from about six at night until four or five in the morning, when it is usually at its lowest ebb. This is a point of importance to physicians. Even five degrees above the average human temperature, if recorded about six at night, is not considered abnormal.

Anything which causes an increase in heat radiation, as perspiration, lowers the temperature, and the open pores of the skin are valuable aids in equalizing the body heat. A person who perspires freely does not suffer with heat, during excessive exercise, as does one whose pores are closed.

One ready means of regulating the body heat is the bath. If one takes a hot bath, the temperature is materially raised by the artificial heat, but there is a recompense in the increase of heat radiation from the skin. If one takes a cold bath, the immediate effect is cooling, but the activity set up within, to create a reaction, soon heats the body to a greater degree than before the bath. The best way to increase the evaporation and thus decrease the temperature of the body is with a tepid shower or a tepid sponge. The tepid water is not so extreme as to create a strong reaction and it will cause a marked decrease in temperature. Thus, for fever patients or for a warm day, the tepid shower or sponge is commended; for a cold day, or for the individual whose circulation is sluggish, the cold bath is desirable. Where the vitality is low, so that there is not sufficient reaction, the bath must be tempered.

Heat generation is also increased by solid foods that require more than normal activity on the part of the glands for digestion. For this reason the food for fever patients should be that most easily digested and should be reduced to the minimum to keep up the strength.

Diuretic foods and beverages, which increase the activity of the skin and the kidneys, also tend to lower the body temperature.

While the elements of the food are being oxidized, the latent (potential) energy released by the oxygen creates mental and physical force and keeps active the metabolic changing of food into tissues and cells, also the changing of cells and tissues into waste.

The young child’s blood circulates freely, his breathing is unrestricted, the waste of the system is fully burned up, potential energy is released, and the result is, he must be active. The effort of the teacher, or of those having the care of children should be, not to restrain the child, but rather to direct his activity in advantageous and effective use of his energy.

Scientists have a means of measuring the energy latent in food material, also the amount of heat given off in the oxidation of a given quantity of waste. The unit of measurement is the calorie,—the amount of heat which will raise one pound of water to four degrees Fahrenheit, or will lift one ton one and fifty-four hundredths.

Truly the body is a busy work-shop. Think of the billions upon billions of cells being formed and destroyed every instant in the liberation of heat and force! Think, also, of the necessity of perfect circulation to bring sufficient blood to the lungs, that it may gather the oxygen and carry it, without pausing for rest, to every tissue of the body! Even in sleep this stream continues incessantly.

There is also a great lesson here in the law of supply and demand;—when the body is at mental or muscular work, the potential energy liberated leaves through muscle or brain, as energy, and is expressed in the result of the work; when the body is at rest, it leaves it as heat (excepting such part as is necessary to carry on metabolism, circulation, etc.) If much muscular energy is called for, a deep, full breath is instinctively drawn to supply the oxygen necessary for the added force required.

If strong mental work is required, attention should be given to exercise and deep breathing the while, that the blood may carry off the waste liberated by brain activity. The difficulty is that in doing close mental work, the body is too frequently bent over a desk in such a manner as to restrict the action of the lungs; thus, the brain worker, in order to continue strong, mental work, must often go into the open air,—as he says, “to rest his brain”, but in reality to re-supply the oxygen required to carry on his work and to carry away the waste liberated by brain energy. The supply for the body work has been called upon for the undue brain work, and this lack of oxygen has produced a state of body designated as “tired.” Until the necessary oxygen has been supplied, the brain and body are not balanced, not “rested.”

Nothing is lost in Nature’s distribution of force and energy. Everything accomplished in life, either in the physical handling of material, the brain work in planning the constructions, the mental movements of thought in art, literature, or science, are all representatives of the heat and energy released from the body, and it is the effort of every man and woman to make the body yield as large an income as possible in the expression of this energy. In order that it may do so, it must be used with intelligence, just as any other great machine must be used intelligently; it must be fed, exercised, and rested judiciously.

Every part of the body is constantly changing. Its work never stops. If kept in thorough repair it must be torn down and rebuilt incessantly. These chemical changes are called collectively metabolism. They are divided into two groups: the chemical process of building up complex substances from simple ones is known as anabolism; the chemical process of oxidizing and breaking down the complex substances into simple ones, so that they are in a state to be excreted, is catabolism. While the process of oxidation in catabolism is going on, heat and energy are set free. Most of the chemical changes in the body are catabolic in character. This work of tearing down and rebuilding body tissues never ceases—even in sleep.

It is not enough that the proper foods be furnished the body in kind and quantity. The essential thing is that the system be kept in condition to assimilate the foods to its needs and to promptly eliminate the waste. Few people assimilate all of the foods eaten; nearly every one eats more than necessary for the body needs.

By assimilation is meant the digestive process by which foodstuffs are made soluble and diffusible, so that they can pass into the blood; also, the metabolic activity by which the food is converted into cells and tissues.

Nature provides for an incomplete knowledge of the amount of re-supply necessary, by enabling the system to carry off a limited amount of surplus food above the bodily requirements.

The distinct steps in anabolism are discussed in the following chapter describing the work of different organs and the chemical changes of foods as they come in contact with the elements in the digestive juices.

CLASSIFICATION OF FOOD ELEMENTS

By foodstuff is meant the chemical elements, appropriated by the animal for the use of the body, as described above. By foods is meant those articles of diet found in the market which contain the chemical elements used by the body in various combinations. Bread, for example, contains all of the foodstuffs and has been called the staff of life, because it sustains life. Foods may contain elements, not foodstuffs, and not used by the body, but cast out as waste, while certain foods, such as sugar, cornstarch, olive oil, and egg albumen, contain only one foodstuff, as will be noted in the following classification of foods and foodstuffs—grouped according to the body uses.

There are many classifications but the following tables, as compiled by a leading dietitian for his practical work in classes, are clear and concise.

Carbonaceous foods:

Sugars Starches Root and tuberous vegetables Green vegetables Fruits Fats

Nitrogenous foods:

Lean meat Eggs Gluten

Carbo-nitrogenous foods:

Cereals Legumes Nuts Milk

The above classifications are made because of the preponderance of certain elements in them, not because they do not contain other substances; e.g. vegetables are mixtures of sugars and starches; fruits are mixtures of sugars, vegetable acids, and salts; milk, legumes, cereals, and nuts contain a more equal division of sugars, fats and proteins and are therefore represented as carbo-nitrogenous; lean meats, with the exception of shell fish, contain no starch, but all meats contain fat, protein, and water, and all, except liver, contain ash.

In the table below, examples are given of foodstuffs in which the chemical elements are almost pure representatives of their classes. Cornstarch, sago, and tapioca are almost pure starch, containing very little of any other element; glucose, cane sugar, syrups, and honey are almost pure sugar; butter, lard, and olive oil are nearly all pure fat; egg albumen, gluten, and lean meat are almost pure protein.