The Philosophy of Health; Volume 2 (of 2) / or, an exposition of the physical and mental constitution of man

by Southwood Smith

922. From the power of absorption possessed by the veins of the stomach and intestines, from the connexion proved to be established between the venous and absorbent systems, and from the discovery of Lippi, that several absorbent branches in the abdomen terminate directly in the pelvis of the kidney, that is now an established fact which was long a conjecture, that there exists a short route from the stomach to the kidneys, so that the extreme rapidity with which certain substances mixed with the aliment appear in the fluid secreted by the kidneys is no longer a matter of wonder.

923. Out of the body urea putrifies with great rapidity. When retained in the system by the extirpation of the kidney, or by placing a ligature around the ureter, such is the septic tendency communicated to the blood that signs of putrescency become manifest even during life, and after death all the soft parts of the body are reduced to a state of putrefaction with extreme rapidity. The suppression of the secretion in the human body, or the undue retention of the matter secreted, induces fever of a malignant kind, in which the symptoms that denote a highly putrid taint in the system are rapidly developed. But for the labour of the kidney, then, a substance would accumulate in the blood, which would quickly lead to the decomposition of the body.

924. It has been shown that the mucous membrane which lines the alimentary canal is studded in its whole extent with glands, which secrete from the blood a large quantity of fluid, These secretions go on without interruption, whether food be taken or not, so that there may be copious alvine evacuations though not a particle of food enter the stomach; and the separation of the matter eliminated from the blood by this extended membrane can no more be dispensed with than that by the skin or the lungs. There is, too, a most intimate sympathy between the secretion of the membrane that lines the internal surface of the body and that carried on by its external covering; any disorder of the one immediately and powerfully disturbs the natural course of the other: hence the diarrhœa, so often produced by the application of cold to the external skin, and the diseases of the skin, so constantly connected with a disordered state of the mucous membrane of the intestines.

925. It is the special office of the large intestines to prepare for its removal, and to carry out of the system the residue of the aliment, together with the excrementitious portion of the bile.

926. It was calculated by Haller, that the different excretory organs remove from the system every twenty-four hours twenty pounds of matter. Of this total loss sustained daily by the human body, it was estimated that four pounds are removed by the skin, four pounds by the lungs, four pounds by the kidneys, and eight pounds by the intestinal canal. In this estimate, which is considered too large, especially that by the intestinal canal, the quantity stated must be understood as denoting the maximum of each secretion.

927. Supposing the ingesta in twenty-four hours to be of food 6 pounds, or 96 ounces, and of oxygen retained in the system 4 ounces, in all 100 ounces, it is estimated that the egesta will be, in twenty-four hours, by the skin, 34 ounces, by the lungs 17 ounces, by the intestines 6 ounces, by the kidneys 40 ounces, and by various other excretions 3 ounces, in all, 100 ounces. These calculations must of course be taken only as approximations to the truth, and as ascribing rather the relative than the positive quantities of matter excreted.

928. Whatever be the absolute quantity or the form of the excretions, it is clear, from the preceding account, that there is constantly removed from the system by the skin a large portion of hydrogen and some carbon; by the lungs a large portion of carbon and some hydrogen; by the liver a large portion of hydrogen and some carbon; by the kidneys a large portion of azote; by the large intestines the residue of the aliment; while, by the deposition of fat, the superabundant nutriment withdrawn from the current of the circulation is laid up in store in some safe part of the body.

929. Most of the processes which have been described are mutually compensating and vicarious. Besides the office which each habitually performs, it is capable of having its action occasionally increased, for the purpose of supplying the deficiency of one or more of its fellows. If perspiration by the skin languish, transudation by the lungs increases; if neither the skin nor the lungs be able to remove the superfluous hydrogen and carbon, these inflammable substances are carried out of the system by the liver in an augmented secretion of bile. If the action of the liver be diminished, that of the kidney is increased; and if the secretion of urine be suppressed, the secretion of bile is augmented. When the absorbents are oppressed by the quantity of fluid poured into the stomach, or when the system is at the point of saturation, and no absorption can go on, the veins take up the superfluous liquids, pour them into the circulating current, and bear them to the kidneys, by which organs they are rapidly separated from the blood, and carried out of the body. The weakness of one organ is compensated by the strength of another; the diminished activity of one process is equalized by the increased energy of some other to which it is allied in nature and linked by sympathy; and thus the evils which would result from the partial and temporary failure of an important function are obviated by some vicarious labour, until the enfeebled organ has recovered its tone, and the natural balance of the functions is restored.

930. The condition acquired by the elementary particles of organized bodies, from their long continuance in the system, which induces the necessity for their excretion, is not known. The chemical elements of the excretions are the very same as those which constitute the organized textures and the nourishment by which they are sustained. Carbon is the basis of the organized body; yet all living bodies, without exception, excrete carbon. Oxygen, hydrogen, and azote, also, without which life cannot be maintained, if retained in the system beyond a given time, are incompatible with the continuance of life. During the chemical changes which these elementary particles undergo, in the course of the vital processes, they appear to enter into some combination, which is no longer compatible with the peculiar mode in which they are disposed in organized and living structures. And one such change, of a very remarkable nature, has been observed, which, it is conceived, has a considerable share in rendering their constant expulsion and renovation indispensable.

931. Out of the condition of life the component elements of organized bodies readily combine so as to form crystals; the peculiar combinations by which they form the constituent textures of organic structures are never crystalline. No crystal is ever seen in the seat of a living and growing vegetable cellule; no crystal is ever found as a constituent part of animal membrane. Whenever a crystal occurs in an organized body it is always the result either of disease or of some artificial process, or else it is an excretion separated from the nourishing fluid and the useful textures. Every one of these textures contains, even in its minutest parts, saline and earthy, as well as vegetable or animal, matter. Why do not these saline and earthy particles as readily combine to form crystals in the organic as they do in the inorganic body? They never do. In the organic body these saline and earthy particles are always so arranged that they are diffused through the membranous fibres or cells, never concentrated in crystals.