The Creation of God, Jacob Hartmann [e manga reader TXT] 📗

The quantity of matter which leaves the human body by way of the skin is very considerable. It is estimated that while 7 grains pass through the lungs per minute, as much as 11 escape through the skin. The amount varies extremely. It is calculated that the total amount of perspiration excreted from the whole body in 24 hours might range from 2 to 20 kilos.

The total amount of perspiration is affected not only by the condition of the atmosphere, but also by the nature and quantity of food taken, the amount of fluid drunk, and the amount of exercise taken. It is also influenced by the mental condition, by medicines and poisons, by disease, and by the relative activity of the other excreting organs, more particularly the kidneys.

The fluid perspiration or sweat, when collected, is found to be a clear colorless fluid, with a strong and distinctive odor varying according to the part of the body from which it is taken. Besides accidental epidermic scales, it contains no structural elements. Its reaction is generally acid, but in cases of excessive secretion may become alkaline. The average amount of solids is about 1.81 per cent, of which about two-thirds consists of organic substances. The chief normal constituents are (1) sodium chloride (common salt), with small quantities of other inorganic salts; (2) various acids of the fatty series, such as fermic, acetic, butyric acid, with probably other acids—CH2O2-C2H4O2—C4H8O2; (3) neutral fats and cholestrine; (4) ammonia (NH3) (urea), and possibly other nitrogenous substances.

The average loss by cutaneous and pulmonary exhalation in a minute is from 17 to 18 grains; the minimum, 11 grains; the maximum, 32 grains; of the average 18 grains 11 pass by the skin and 7 by the lungs. The maximum loss by exhalation, cutaneous and pulmonary, in twenty-four hours is about 3¾ pounds; the minimum, about 1½ pounds. Valentine found the whole quantity lost by exhalation from the respiratory and cutaneous surfaces of a healthy man who consumed daily 40,000 grains of food and drink to be 19,000 grains, or 2½ pounds. Subtracting from this, for the pulmonary exhalation, 5,000 grains, and for the excess of the weight of the exhaled carbonic acid over that of the equal volume of the inspired oxygen, 2,256 grains, the remainder, 11,744 grains, or nearly 1​5⁄7​ pounds, may represent an average amount of cutaneous exhalation in a day.

The Kidneys, two in number, are excretory organs. They are deeply seated in the lumbar region, one on each side of the vertebral column, at the back of the abdominal cavity, and behind the peritoneum. The kidneys measure about 4 inches in length, 2½ inches in breadth, and 1½ inches in thickness. The left is usually longer and narrower than the right one. The weight of the kidney is usually stated to be about 4½ ounces in the male and somewhat less in the female.

The excretory apparatus consists of fine tubules (the tubuli urineferi), malpighian bodies, blood-vessels, nerves, and lymphatics, etc.

The kidneys are highly vascular, and receive their blood from the renal arteries, which are very large in proportion to the organ they supply. Each artery breaks up into four or five branches, these again subdivide and break up into capillaries in the substance of the kidney. The veins arise by numerous venous radicals from the capillary network of the kidney, as seen near the surface of the gland, and collect the blood from the capillary plexus around the convoluted tubules which mainly compose this part, the smaller veins joining together and ultimately forming a single vein and ending in the inferior vena cava.

The kidneys are so arranged by their anatomical structure—that of the cortical and medullary substance, the tubuli urineferi, pyramids, malpighian bodies, etc.—that they separate from the blood the solids in a state of solution. The secretion takes place by the agency of the gland cells, and equally in all the parts of the urine tubes. The protoplasmic cells which line at least a large portion of the tubuli urineferi elaborate from the blood certain substances, and discharge them into the channels of the tubules. All parts of the tubular system of the kidney take part in the secretion of urine as a whole, but there is another provision of vessels for a more simple draining off of the water from the blood when required.

The large size of the renal arteries and veins permits so rapid a transit of the blood through the kidneys that the whole of the blood is purified by them. The secretion of urine is rapid in comparison with other secretions, and as each portion is secreted, it propels that which is already in the tubes onwards into the pelvis of the kidney. Thence, through the ureter, the urine passes into the bladder, into which its rate and mode of entrance has been watched. The urine does not enter the bladder at any regular rate, nor is there a synchronism in its movement through the two ureters. In a recumbent posture the urine collects for a little time in the ureters, then flows gently, and if the body is raised, runs from them in a stream till they are empty. Its flow is increased in deep inspiration, or straining, and in active exercise, and in fifteen or twenty minutes after meals.

Substances taken into the stomach pass very rapidly through the circulation. It does not take longer than one minute for ferrocyanide of potassium to pass through. Vegetable substances pass in from sixteen to thirty-five. Neutral alkaline salts with vegetable acids, which were generally decomposed in transitu, made the urine alkaline in twenty-eight to forty-seven minutes. But the time of passage varied much; and the transit was always slow when the substances were taken during digestion.

There are really two distinct parts in the kidney—the actively secreting part, the epithelium of the secreting tubules; and what maybe called a filtering part, the malpighian bodies.

The specific gravity of urine is 1020—that is, the average human urine. Urine varies—in the morning before breakfast it is darker, urina sanguinis; urine secreted shortly after the introduction of any considerable quantity of fluid into the body, urina potus; and the urine evacuated immediately succeeding a solid meal of food, urina cibi. The last kind contains a larger quantity of solid matter than either of the others, the first and second being largely diluted with water.

Specific gravity: The morning urine is best calculated for analysis. The average healthy range may be stated at 1015 in the winter to 1025 in the summer, and variations of diet and exercise may make a great difference. In disease, the variations may be greater; sometimes descending in albuminaria to 1004, and frequently ascending in diabetes, when the urine is loaded with sugar, to 1050, or even to 1060.

The whole quantity of urine secreted in twenty-four hours is subject to variations according to the amount of fluid drunk, and the proportion of the latter passing off from skin, lungs, and alimentary canal. The average quantity voided in twenty-four hours by healthy male adults from twenty to forty years of age amounts to 52½ fluid ounces.

The chemical composition of urine. The average quantity of each constituent of the urine in 1,000 parts is: