Part 12

* * * * *

The intestines, in their work of elimination, pass off all undigested matter. They also carry off bile pigment, bile salts, mucus, amino acids, and other decomposition of proteins,—also a little unabsorbed fats and bacterial decomposition taking place in the intestines. Coarse articles of food containing fibres which do not digest, such as the bran of grains and the coarser fruits and vegetables (though much of their substances are not food in the strictest sense) are valuable to increase the peristaltic movements of the intestines and to act as a carrying body to move the waste excretions along their course.

The combustion, or burning of fuel in any form, (oxidation for the release of latent heat and energy) always leaves some parts which are not used as heat or energy, and it is the work of the intestines to eliminate much of this refuse. When coal is burned, gas, smoke and cinders or clinkers, constitute the waste and if these were not allowed to escape from a stove the fire would soon go out—the smoke and gas would smother it and the clinkers would prevent the circulation of oxygen and soon clog and fill the stove. The same is true in the body—the carbonic acid gas not being allowed to pass off would soon put out the fires of life; it would poison the body and stunt the action of the nerves. If the nitrogenous waste (like ashes and cinders) is not eliminated by the kidneys, one will die in convulsions in one or two days.

The absolute necessity of a free elimination of waste will be readily seen.—If the engine is to do its best work, the engineer sees that it is kept perfectly clean—otherwise it becomes clogged, does inefficient work and the clogging soon wears out some parts. The same is true in the body,—clogging in any part overworks and wears out other parts dependent upon the work of the one.

Summary

Let us sum up the processes which the food undergoes in its conversion into condition to be absorbed by the body; in its absorption through the walls of the intestines and stomach; and the metabolic processes which it undergoes in being converted into heat and energy and again broken down and eliminated as waste.

The Saliva begins the digestion of starches and sugars in the mouth. This digestion is continued by the saliva in the stomach.

The Stomach, when in normal condition, thoroughly digests the proteins. If any proteins fail of digestion in the stomach the process is completed in the intestines.

The Intestines, aside from their work of digestion and absorption, excrete bile pigment, bile salts, animal acids, mucus and other decomposition of proteins, with bacterial fermentation and putrefactions; also such food materials as are not digested.

The small intestine digests and absorbs the fats and continues the digestion of starches, sugars and fats when this digestion is not completed in the stomach.

The large part of the food is absorbed through the small intestine, though a small part is absorbed through the walls of the stomach and through the large intestine.

Fats are almost entirely absorbed in the small intestine. They are absorbed through the lacteals and are carried into the blood stream.

The Liver. The proteins and the starches (converted into maltose) and sugars pass into the liver. The sugar (including the sugar in vegetables, milk, fruits and that used for sweetening, as well as the carbohydrates which have been changed into maltose), is converted into glycogen in the liver, stored here for a time and again broken down into sugar that it may be in condition to be absorbed into the blood.

The proteins pass through the liver but are not acted upon by this organ until they again return to the liver through the blood stream, after they have been partly oxidized in the tissues. The liver further oxidizes them putting them into condition to be excreted by the kidneys and intestines.

The liver also breaks up the worn out red corpuscles, putting them into condition to be eliminated in the bile.

It oxidizes and renders harmless poisonous substances absorbed in the food, such as fermented food products and alcohol.

The Muscles oxidize the fats and sugars liberating the latent heat and energy.

They partly oxidize proteins which are further broken up in the liver.

The Nerves oxidize food materials stored in the nerve cells, providing nervous energy.

The Lungs absorb oxygen and throw off carbon dioxid, watery vapor and some organic substances.

The Kidneys and The Skin purify the blood by excreting water, carbon dioxid and nitrogenous waste.

FACTORS INFLUENCING DIGESTION

As before stated, it is not the food eaten, but that which the body digests and assimilates, or appropriates to its needs, which counts; many factors influence such nourishment. The principal ones are the forceful circulation, the breathing of plenty of oxygen, and the resultant free elimination of waste.

* * * * *

If one has no appetite, by far the safest method is to abstain from food until the system calls for it, or to eat but a very little of the lightest food at regular meal times; be careful not to mince between meals nor to eat candy nor pickles. Be sure that the lack of appetite is not due to mental preoccupation which does not let the brain relax long enough for the physical needs to assert themselves. One should relax the brain in pleasant thoughts during a meal.

If the appetite is lacking, because of physical exhaustion, it is unwise to eat, because the digestive organs are tired, and to load a tired stomach with food, still further weakens it and results in indigestion. The better plan is to drink two glasses of cold water and lie down for an hour; if there is still no desire for food, drink freely of water, but abstain from food until hungry.

This should not lead one into forming the habit of irregular eating, however. The stomach forms habits and the supply of food must be regular, just as the nursing child must be fed regularly, or digestive disturbance is sure to result.

A wise provision of Nature makes the system, in a normal condition, its own regulator, protesting against food when it has not assimilated or eliminated that consumed. One should learn to obey such protests and cut down the quantity when Nature calls “enough.”