It is a curious but necessary provision of Nature, that the blood, besides carrying the digested nourishment and the life-giving oxygen to all portions of the body, also removes all of the waste, poisonous products from the system. And from the very nature of our physical organization, the blood is the only agent that can be employed in this dual capacity.
It has been explained in Chapter IV. how the blood is revitalized by the addition of digested nourishment in other words, how the blood is made over again.
It must be understood, of course, that each of the organs has a circulatory system of its own. Now, impure blood is brought into the kidneys through a channel known as the renal artery. This artery sub-divides, and the subdivision is carried on and on, until every portion of the kidneys is supplied with arterial blood. From the branches of the arteries the blood passes into capillaries, which are the minute channels that exist between arteries and veins. But in the kidneys, instead of a single there is a double system of capillaries. These capillaries exist in numerous plexuses or net-works, and before the blood can pass into the renal vein, it must flow through the capillary membranes and thus on through the entire and complicated system of these minute vessels.
Now the blood contains a surplus of water, and in solution, many waste matters, the most important of which is a substance called urea. While passing through the capillaries the blood is filtered; the surplus water and the solids that it holds in solution are absorbed through the thin membranes, and are passed on to the ureters, while the blood thus purified, enters the roots of the -venous system that empties into the renal vein. In this manner, the blood that has been ridded of its waste products is returned to the general circulation.
The ureter is a tube that carries the urine the surplus water and its dissolved waste products down to the urinary bladder, where it is stored until ejected from the latter.
Yet not all of the surplus moisture can be carried off by the kidneys. The skin has its share to do. If the skin be not active in its work of excreting surplus moisture then that much more is forced upon the kidneys, and the latter organs, when overworked, become weakened and diseased.
The skin has three purposes. It protects the delicate tissues of the outer surfaces of the body; it acts as an organ of sense (touch) and it excretes moisture. It is with this last of its functions that we have now to do.
There are, in reality, two skins, the inner, or true skin, and the outer skin, or epidermis. The true skin is highly sensitive, and is richly supplied with :blood vessels and with nerves, is highly active at all times, and requires incessant repair of its tissues by the blood. In it there are two kinds of glands, the sweat glands and the sebaceous: It is in the sebaceous glands that the hair has its origin.
Closely in touch with the blood vessels everywhere in the true skin, are the sweat glands. From these the surplus moisture and its dissolved impurities are filtered and absorbed. As they fill with this waste moisture and its dissolved contents, they empty them-selves upon the outer surface of the epidermis.
Under ordinary circumstances this moisture is not visible, and is then called insensible perspiration. But when, on account of unusual muscular exertion or increase of external or internal heat the sweat glands are very actively worked, the perspiration exudes in visible drops. In either case the perspiration is evaporated and removed by the air, and thus, the depurating work that the kidneys did not do, is performed by the skin.
It is clear, then, why exercise and deep breathing, by hastening the flow of the blood and sending more oxygen through the body to assist in the removal of waste matter, aid in getting rid of impurities through the urine and the sweat.
As has been explained in Chapter IV. a great deal of the waste matter of the body is exhaled from the lungs every time that an expiration takes place.
But what of the waste matter left after the food has been digested, and what of the food swallowed but not digested In Chapter IV. we have followed the course of the food through the stomach and the small intestine. By the time that the food is out of the small intestine the nourishment has been pretty thoroughly extracted from it. From the small intestine the food residue is passed into the large intestine, or colon, often known as the lower bowel. This intestine is divided, for convenience of description, into three parts, the ascending, the transverse and the descending colon. The shape of the colon is something like that of a horseshoe, with the arch, or transverse colon uppermost. All the way along the colon the food residue is forced or passed on, by the continued contractions of the involuntary muscles of the intestine. Whether or no a small amount of digestion takes place in the colon is a question that physiologists have not yet decided. But the food residue, in – the form of feces, passes on until, from the lower end of the descending colon, it is expelled through the rectum.
As in the case of the kidneys and the skin, exercise aids in the expulsion of waste matter through the colon. But exercises that strongly affect the abdominal region, build up the strength of the involuntary muscles of the colon, and thus aid in the expulsion of waste by this channel.
It is to be borne in mind, always, that, as has been shown, the .expulsion of waste matters through the depurating organs is identical with the purification’ of the blood. For this reason, the liver, having a circulatory system of its own, is, outside of its other important duties, a depurating organ of no mean. rank.
It is a truism that it would be utter folly to consider vital power apart from the possession of a high state of functional vigor.
The value of the latter to human life cannot be overestimated. External muscular strength and vigor are useful and are worth far more than the efforts essential to acquire it. It serves to beautify the body and invest it with the power of moving quickly, gracefully and easily. It enables you to perform wonderful feats of strength and agility. But this external strength is really of minor value when compared with internal vital strength, though the development of the former in nearly all cases assists in building up the latter. Therefore, true physical culture first of all, gives attention to increasing the powers of those great vital organs which control the functional process that build and maintain life, health and strength.
Your arms and legs which contain a large portion of external muscular strength can be amputated and you will still live, but remove any one of the vital organs and death will quickly ensue.
This very emphatically illustrates to you the value of strength in these organs. They are necessary to your existence. You need them every instant of your life.
The end of the important vital functions which they perform is the maintenance of bodily health in a satisfactory condition. Weak vital organs always mean poor health. As a rule when strength of the external muscular system is possessed, the internal organs are strong to a similar degree. This however does not necessarily follow in every case. If you were to develop certain parts of the body and allow other parts to become weak from inaction, it would not follow that the vital organs would become stronger.
Poorly developed and weak external muscles may, -in some instances, cause some amount of suffering, but your experiences in this respect would be of small . importance compared to what you would have to endure if the vital centers were afflicted with similar weakness.
Let us distinctly remember that every process of the body which tends to keep you in a normal condition, which is inclined to make your spirits buoyant or your mind clear, depends entirely upon the harmonious working of the internal functional system, and this cannot be obtained until every organ possesses normal strength.
For instance, let us take the stomach, the organ in which the blood-making process first begins. Many thousands of human beings suffer daily martyrdom because of chronic weakness of the stomach. Famous physicians have remarked that nearly all disease begins in the stomach.
Now, going into this process of blood-making, we find that the absorbent glands perform important offices. These glands are freely supplied to the wall of the stomach, and in fact to the entire alimentary canal. They take up from the food the elements of nourishment which the body needs to repair its constant waste.
I have no intention of worrying my reader with unnecessary detail in reference to the physiological processes connected with the making of blood. This is a study in itself, and to those who may desire a further familiarity ‘with them, I would advise the reading of some standard work on physiology. I merely mention these few facts in connection with blood-making in order to assist in impressing on you the great importance of internal functional vigor.
Now, after the liquid which is later to be made into blood is taken up by the absorbent glands, the next important organ which receives it is the heart which works continually from birth until death. The importance of strength and the disastrous results of weakness in this organ will therefore be made manifest. And the heart is the prime factor in the scheme of blood circulation.
This very brief description of the process of blood-making and circulation should assist in indicating the vast importance of internal functional strength.
The stomach and all the important organs located in the vital centers must be vigorous, must possess normal strength, or severe suffering will ensue.
Fine rich blood, free from impurities, is necessary to the strength of every organ of the body. It is to the body that which food is to the stomach. It furnishes those elements essential in repairing waste, in replacing dead, worn-out tissue. It also furnishes the means by which this worn-out tissue is brought to the depurating organs to be expelled. Every minute cell that composes your body, is made from blood. Can anything more emphatically prove the necessity for having your blood as pure as possible?