Every motion in every part of the body has a special muscle to produce it, and many have other muscles to restore the part moved to its natural state. The muscles that move or bend any part are called flexors, and those that restore the natural position are called extensors.
Fig. 53 represents the muscles of the arm after the skin and flesh are removed. They are all in smooth silky cases, laid over each other, and separated both by the smooth membranes that encase them and by layers of fat, so as to move easily without interfering with each other. They are fastened to the bones by strong tendons and cartilages; and around the wrist, in the drawing, is shown a band of cartilage to confine them in place. The muscle marked 8 is the extensor that straightens the fingers after they have been closed by a flexor the other side of the arm. In like manner, each motion of the arm and fingers has one muscle to produce it and another to restore to the natural position.
The muscles are dependent on the brain and nerves for power to move. It has been shown that the gray matter of the brain and spinal marrow furnishes the stimulating power that moves the muscles, and causes sensations of touch on the skin, and the other sensations of the several senses. The white part of the brain and spinal marrow consists solely of conducting tubes to transmit this influence. Each of the minute fibrils of the muscles has a small conducting nerve connecting it with the brain or spinal marrow, and in this respect each muscular fibril is separate from every other.
When, therefore, the mind wills to move a flexor muscle of the arm, the gray matter sends out the stimulus through the nerves to the cells of each individual fibre of that muscle, and they contract. When this is done, the nerve of sensation reports it to the brain and mind. If the mind desires to return the arm to its former position, then follows the willing, and consequent stimulus sent through the nerves to the corresponding muscle; its cells contract, and the limb is restored.
When the motion is a compound one, involving the action of several muscles at the same time, a multitude of impressions are sent back and forth to and from the brain through the nerves. But the person acting thus is unconscious of all this delicate and wonderful mechanism. He wills the movement, and instantly the requisite nervous power is sent to the required cells and fibres, and they perform the motions required. Many of the muscles are moved by the sympathetic system, over which the mind has but little control.
Among the muscles and nerves so intimately connected, run the minute capillaries of the blood, which furnish nourishment to all.
Fig. 54 represents an artery a a, which brings pure blood to a muscle from the heart. After meandering through the capillaries at c, to distribute oxygen and food from the stomach, the blood enters the vein, b, loaded with carbonic acid and water taken up in the capillaries, to be carried to the lungs or skin, and thrown out into the air.
The manner in which the exercise of the muscles quickens the circulation of the blood will now be explained. The veins abound in every part of every muscle, and the large veins have valves which prevent the blood from flowing backward. If the wrist is grasped tightly, the veins of the hand are immediately swollen. This is owing to the fact that the blood is prevented from flowing toward the heart by this pressure, and by the vein-valves from returning into the arteries; while the arteries themselves, being placed deeper down, are not so compressed, and continue to send the blood into the hand, and thus it accumulates. As soon as this pressure is removed, the blood springs onward from the restraint with accelerated motion. This same process takes place when any of the muscles are exercised. The contraction of any muscle presses some of the veins, so that the blood can not flow the natural way, while the valves in the veins prevent its flowing backward. Meantime the arteries continue to press the blood along until the veins become swollen. Then, as soon as the muscle ceases its contraction, the blood flows faster from the previous accumulation.
If, then, we use a number of muscles, and use them strongly and quickly, there are so many veins affected in this way as to quicken the whole circulation. The heart receives blood faster, and sends it to the lungs faster. Then the lungs work quicker, to furnish the oxygen required by the greater amount of blood. The blood returns with greater speed to the heart, and the heart sends it out with quicker action through the arteries to the capillaries. In the capillaries, too, the decayed matter is carried off faster, and then the stomach calls for more food to furnish new and pure blood. Thus it is that exercise gives new life and nourishment to every part of the body.
It is the universal law of the human frame that exercise is indispensable to the health of the several parts. Thus, if a blood-vessel be tied up, so as not to be used, it shrinks, and becomes a useless string; if a muscle be condemned to inaction, it shrinks in size and diminishes in power; and thus it is also with the bones. Inactivity produces softness, debility, and unfitness for the functions they are designed to perform.
Now, the nerves, like all other parts of the body, gain and lose strength according as they are exercised. If they have too much or too little exercise, they lose strength; if they are exercised to a proper degree, they gain strength. When the mind is continuously excited, by business, study, or the imagination, the nerves of emotion and sensation are kept in constant action, while the nerves of motion are unemployed. If this is continued for a long time, the nerves of sensation lose their strength from over-action, and the nerves of motion lose their power from inactivity. In consequence, there is a morbid excitability of the nervous, and a debility of the muscular system, which make all exertion irksome and wearisome.
The only mode of preserving the health of these systems is to keep up in them an equilibrium of action. For this purpose, occupations must be sought which exercise the muscles and interest the mind; and thus the equal action of both kinds of nerves is secured. This shows why exercise is so much more healthful and invigorating when the mind is interested, than when it is not. As an illustration, let a person go shopping with a friend, and have nothing to do but look on. How soon do the continuous walking and standing weary! But, suppose one, thus wearied, hears of the arrival of a very dear friend: she can instantly walk off a mile or two to meet her, without the least feeling of fatigue. By this is shown the importance of furnishing, for young persons, exercise in which they will take an interest. Long and formal walks, merely for exercise, though they do some good, in securing fresh air, and some exercise of the muscles, would be of triple benefit if changed to amusing sports, or to the cultivation of fruits and flowers, in which it is impossible to engage without acquiring a great interest.
It shows, also, why it is far better to trust to useful domestic exercise at home than to send a young person out to walk for the mere purpose of exercise. Young girls can seldom be made to realize the value of health, and the need of exercise to secure it, so as to feel much interest in walking abroad, when they have no other object. But, if they are brought up to minister to the comfort and enjoyment of themselves and others, by performing domestic duties, they will constantly be interested and cheered in their exercise by the feeling of usefulness and the consciousness of having performed their duty.
There are few young persons, it is hoped, who are brought up with such miserable habits of selfishness and indolence that they can not be made to feel happier by the consciousness of being usefully employed. And those who have never been accustomed to think or care for any one but themselves, and who seem to feel little pleasure in making themselves useful, by wise and proper influences can often be gradually awakened to the new pleasure of benevolent exertion to promote the comfort and enjoyment of others. And the more this sacred and elevating kind of enjoyment is tasted, the greater is the relish induced. Other enjoyments often cloy; but the heavenly pleasure secured by virtuous industry and benevolence, while it satisfies at the time, awakens fresh desires for the continuance of so ennobling a good.
CHAPTER IX.
HEALTHFUL FOOD.
The person who decides what shall be the food and drink of a family, and the mode
s of its preparation, is the one who decides, to a greater or less extent, what shall be the health of that family. It is the opinion of most medical men, that intemperance in eating is one of the most fruitful of all causes of disease and death. If this be so, the woman who wisely adapts the food and cooking of her family to the laws of health removes one of the greatest risks which threatens the lives of those under her care. But, unfortunately, there is no other duty that has been involved in more doubt and perplexity. Were one to believe all that is said and written on this subject, the conclusion probably would be, that there is not one solitary article of food on God’s earth which it is healthful to eat. Happily, however, there are general principles on this subject which, if understood and applied, will prove a safe guide to any woman of common sense; and it is the object of the following chapter to set forth these principles.
All material things on earth, whether solid, liquid, or gaseous, can be resolved into sixty-two simple substances, only fourteen of which are in the human body; and these, in certain proportions, in all mankind.
Thus, in a man weighing 154 lbs. are found, 111 lbs. oxygen gas, and 14 lbs. hydrogen gas, which, united, form water; 21 lbs. carbon; 3 lbs. 8 oz. nitrogen gas; 1 lb. 12 oz. 190 grs. phosphorus; 2 lbs. calcium, the chief ingredient of bones; 2 oz. fluorine; 2 oz. 219 grs. sulphur; 2 oz 47 grs. chlorine; 2 oz. 116 grs. sodium; 100 grs. iron; 290 grs. potassium; 12 grs. magnesium; and 2 grs. silicon.
These simple substances are constantly passing out of the body through the lungs, skin, and other excreting organs.
It is found that certain of these simple elements are used for one part of the body, and others for other parts, and this in certain regular proportions. Thus, carbon is the chief element of fat, and also supplies the fuel that combines with oxygen in the capillaries to produce animal heat. The nitrogen which we gain from our food and the air is the chief element of muscle; phosphorus is the chief element of brain and nerves; and calcium or lime is the hard portion of the bones. Iron is an important element of blood, and silicon supplies the hardest parts of the teeth, nails, and hair.
Water, which is composed of the two gases, oxygen and hydrogen, is the largest portion of the body, forming its fluids; there is four times as much of carbon as there is of nitrogen in the body; while there is only two per cent as much phosphorus as carbon. A man weighing one hundred and fifty-four pounds, who leads an active life, takes into his stomach daily from two to three pounds of solid food, and from five to six pounds of liquid. At the same time he takes into his lungs, daily, four or five thousand gallons of air. This amounts to three thousand pounds of nutriment received through stomach and lungs, and then expelled from the body, in one year; or about twenty times the man’s own weight.
The change goes on in every minute point of the body, though in some parts much faster than in others; as set forth in the piquant and sprightly language of Dr. O. W. Holmes [Footnote: Atlantic Almanac, 1869, .], who, giving a vivid picture of the constant decay and renewal of the body, says:
“Every organized being always lives immersed in a strong solution of its own elements.”
“Sometimes, as in the case of the air-plant, the solution contains all its elements; but in higher plants, and in animals generally, some of the principal ones only. Take our own bodies, and we find the atmosphere contains the oxygen and the nitrogen, of which we are so largely made up, as its chief constituents; the hydrogen, also, in its watery vapor; the carbon, in its carbonic acid. What our air-bath does not furnish us, we must take in the form of nourishment, supplied through the digestive organs. But the first food we take, after we have set up for ourselves, is air, and the last food we take is air also. We are all chameleons in our diet, as we are all salamanders in our habitats, inasmuch as we live always in the fire of our own smouldering combustion; a gentle but constant flame, fanned every day by the same forty hogsheads of air which furnish us not with our daily bread, which we can live more than a day without touching, but with our momentary, and oftener than momentary, aliment, without which we can not live five minutes.”
“We are perishing and being born again at every instant. We do literally enter over and over again into the womb of that great mother, from whom we get our bones, and flesh, and blood, and marrow. ‘I die daily’ is true of all that live. If we cease to die, particle by particle, and to be born anew in the same proportion, the whole movement of life comes to an end, and swift, universal, irreparable decay resolves our frames into the parent elements.”
“The products of the internal fire which consumes us over and over again every year, pass off mainly in smoke and steam from the lungs and the skin. The smoke is only invisible, because the combustion is so perfect. The steam is plain enough in our breaths on a frosty morning; and an over-driven horse will show us, on a larger scale, the cloud that is always arising from own bodies.”
“Man walks, then, not only in a vain show, but wrapped in an uncelestial aureole of his own material exhalations. A great mist of gases and of vapor rises day and night from the whole realm of living nature. The water and the carbonic acid which animals exhale become the food of plants, whose leaves are at once lungs and mouths. The vegetable world reverses the breathing process of the animal creation, restoring the elements which that has combined and rendered effete for its own purposes, to their original condition. The salt-water ocean is a great aquarium. The air ocean in which we live is a ‘Wardian case,’ of larger dimensions.”
It is found that the simple elements will not nourish the body in their natural state, but only when organized, either as vegetable or animal food; and, to the dismay of the Grahamite or vegetarian school, it is now established by chemists that animal and vegetable food contain the same elements, and in nearly the same proportions.
Thus, in animal food, carbon predominates in fats, while in vegetable food it shows itself in sugar, starch, and vegetable oils. Nitrogen is found in animal food in the albumen, fibrin, and caseine; while in vegetables it is in gluten, albumen, and caseine.
It is also a curious fact that, in all articles of food, the elements that nourish diverse parts of the body are divided into separable portions, and also that the proportions correspond in a great degree to the wants of the body. For example, a kernel of wheat contains all the articles demanded for every part of the body. Fig. 55 represents, upon an enlarged scale, the position and proportions of the chief elements required. The white central part is the largest in quantity, and is chiefly carbon in the form of starch, which supplies fat and fuel for the capillaries. The shaded outer portion is chiefly nitrogen, which nourishes the muscles, and the dark spot at the bottom is principally phosphorus, which nourishes the brain and nerves. And these elements are in due proportion to the demands of the body. A portion of the outer covering of a wheat-kernel holds lime, silica, and iron, which are needed by the body, and which are found in no other part of the grain. The woody fibre is not digested, but serves by its bulk and stimulating action to facilitate digestion. It is therefore evident that bread made of unbolted flour is more healthful than that made of superfine flour. The process of bolting removes all the woody fibre; the lime needed for the bones; the silica for hair, nails, and teeth; the iron for the blood; and most of the nitrogen and phosphorus needed for muscles, brain, and nerves.
Experiments on animals prove that fine flour alone, which is chiefly carbon, will not sustain life more than a month, while unbolted flour furnishes all that is needed for every part of the body. There are cases where persons can not use such coarse bread, on account of its irritating action on inflamed coats of the stomach. For such, a kind of wheaten grit is provided, containing all the kernel of the wheat, except the outside woody fibre.
When the body requires a given kind of diet, specially demanded by brain, lungs, or muscles, the appetite will crave food for it until the necessary amount of this article is secured. If, then, the food in which the needed aliment abounds is not supplied, other food will be taken in larger quantities than needed u
ntil that amount is gained. For all kinds of food have supplies for every want of the body, though in different proportions. Thus, for example, if the muscles are worked a great deal, food in which nitrogen abounds is required, and the appetite will continue until the requisite amount of nitrogen is secured. If, then, food is taken which has not the requisite quantity, the consequence is, that more is taken than the system can use, while the vital powers are needlessly taxed to throw off the excess.
These facts were ascertained by Liebig, a celebrated German chemist and physicist, who, assisted by his government, conducted experiments on a large scale in prisons, in armies, and in hospitals. Among other results, he states that those who use potatoes for their principal food eat them in very much larger quantities than their bodies would demand if they used also other food. The reason is, that the potato has a very large proportion of starch that supplies only fuel for the capillaries and very little nitrogen to feed the muscles. For this reason lean meat is needed with potatoes.
In comparing wheat and potatoes we find that in one hundred parts wheat there are fourteen parts nitrogen for muscle, and two parts phosphorus for brain and nerves. But in the potato there is only one part in one hundred for muscle, and nine tenths of one part of phosphorus for brain and nerves.
The articles containing most of the three articles needed generally in the body are as follows: for fat and heat-making — butter, lard, sugar, and molasses; for muscle-making — lean meat, cheese, peas, beans, and lean fishes; for brain and nerves — shell-fish, lean meats, peas, beans, and very active birds and fishes who live chiefly on food in which phosphorus abounds. In a meat diet, the fat supplies carbon for the capillaries and the lean furnishes nutriment for muscle, brain, and nerves. Green vegetables, fruits, and berries furnish the acid and water needed.
In grains used for food, the proportions of useful elements are varied; there is in some more of carbon and in others more of nitrogen and phosphorus. For example, in oats there is more of nitrogen for the muscles, and less carbon for the lungs, than can be found in wheat. In the corn of the North, where cold weather demands fuel for lungs and capillaries, there is much more carbon to supply it than is found in the Southern corn.
Complete Works of Harriet Beecher Stowe Page 851