The Glands In The Skin, The Nails

A Handbook of Health
by Woods Hutchinson

(Page 17 of 30)

The Glands In The Skin

Sweat Glands. Like all the pavement (epithelial) surfaces of the body, inside and out, the skin has the power of making glands by dipping down little pouches or pockets into the layers below. In the skin, these little gland-pockets are of two kinds, the sweat glands and the hair glands.

The sweat glands are tiny tubes which go twisting down through the different pavement layers, through the basement layer, and right into the coat of fat, which lies just under the skin. The tube of the sweat gland soaks, or picks, out of the blood some of the waste-stuff - just as the kidney tube does in the kidney, - together with a good deal of water and a small amount of delicate oil, and pours them out on the surface of the body in the form of the "sweat," or perspiration.

As you will remember, when the muscles work hard and pour more waste into the blood, then the heart pumps larger amounts of blood out into the skin; and this causes it to redden. The sweat glands work harder to purify this extra blood, and they pour out the waste and oil and water on the surface. As soon as this water gets upon our hot skin, it begins to evaporate and cool us off, as well as to carry off some of the waste in the form of gas. The trace of oil in the perspiration helps to lubricate the skin and keep it soft; but when too much of it is poured out we have that greasy feeling, which we have all felt after perspiring freely.

From all this cooling and breathing and blood-purifying work going on upon the surface of our skin, you can easily see why it is so important that all our clothing should be loose and porous and that next the skin easily washed; else it will very soon become clogged up and greasy, and shut off the breathing and blood-purifying work of the skin and make it dirty and unhealthy. This continual mist of water, rising and bubbling up through our skin like springs out of a hillside, is another of nature's wonderful ways of cleansing the skin and of preventing any kind of dirt from permanently sticking to or lodging in it. Remember, you do not need to dig below the surface when you wash.

Hair Glands. The other kind of skin glands, the hair glands, are also pouches growing out from the deepest part of the stem of the hair, known as the root, or hair bulb.

From the root of the hairs, two or three little bundles of muscle run up toward the surface of the skin. When these contract, they pull the root of the hair up toward the surface, causing the hair to stand erect, or "bristle," as we say. This is what makes the hair on a dog's or a cat's back stand up when he is angry; but the commonest use of the movement is, when animals are cold, to make their coats stand out so as to hold more air and retain the body-heat better. We have lost most of our hairy coating, but whenever we get chilly, whether from cold or from fright, these little muscles of our hair bulbs contract and pull the hair glands of our skin up toward the surface, so that it looks all "pimply" or "goose-skinned."

Each hair pouch has sprouted out from its sides a pair of tiny pouches, which form oil glands to lubricate the hair and keep it sleek and flexible. It is hard to beat nature at her own game, and her method of oiling the hair is far superior to any hair oil that can be put on from the outside. Keep your hair well brushed and washed, and nature will oil it for you much better than any hair oil or scalp reviver ever invented.

The Nails

How the Nails are Made. Another "trade," which our wonderful skin has literally "at its fingers' ends," is that of making nails. Indeed, every kind of scale, armor, fur, feather, and leather coating possessed by bird, beast, or fish was made by, and out of, the skin. Nail-making, however, is one of its simplest feats, as it is carried out merely by turning a little patch, or area, of itself into a horn-like substance. This, the skin of insects, of fishes, of crocodiles, etc., does all over the surface of their bodies; but in animals and birds only a number of little patches at the tips of the toes harden up in this way, to form the claws or nails; and in birds, the beak; and in some animals, the horns. So it is quite correct to call the substance of our nails "horn-like."

In some animals and birds, these little horny patches at the ends of the toes grow out into long, curved hooks, or broad, digging chisels and scoops; but on our own fingers, they simply make a little mould over the finger-tip. If, however, they are protected from being broken off, they will grow four or five inches long; in fact, they are carefully trained to do this by some of the upper classes in China, merely for the purpose of showing that they have never been obliged to degrade themselves, as they foolishly regard it, by working with their hands.

You can easily prove that the nails do grow constantly from the root or base, out toward the tip, by watching, some time when you have pounded one of your nails, how the black or discolored patch in it will grow steadily outward toward the tip, where it will be broken off and shed.

You cannot see the softest and youngest row, or layer, of the nail cells at the base, because a fold of skin, the nail fold, has been doubled, or folded, over them to protect them while they are young and soft. It is not best to push this fold of skin back too much, as, by so doing, you may uncover the young nail cells while they are soft and tender, and expose them to injury. The reason why there is a little whitish crescent at the base of the nail is that the cells of the nail do not grow hard and horn-like and transparent until they have grown out a quarter of an inch or so from under the fold, but at first look whitish, or opaque, like the rest of the skin.

Health Shown by the Color of the Nails. Your nails and your lips are not really any redder, or pinker, than the rest of your skin; but the cells forming them are clear and transparent and allow the red blood to show through. This is why we often look at the nails and lips to see what the color of the blood is like, and how well or badly it is circulating. If the blood is anemic, or thin, then both lips and nails are pale and dull. If the blood is healthy and the circulation good, then the nails are pink, and the lips clear red. If, on the other hand, the circulation is bad, as in some forms of lung disease and heart disease, so that the blood is loaded with carbonic acid until it is blue and dark, then the lips may become purplish or dark blue, and the finger nails nearly the same color.

Houghton Mifflin Company
Copyright, 1911, By Woods Hutchinson
All Rights Reserved
Tenth Impression

About the Author

Woods Hutchinson (1862-1930) was an American physician, born at Selby, Yorkshire, England. He graduated from Penn College, Oskaloosa, Iowa, in 1880 and received his medical degree from the University of Michigan four years later. He worked as a professor of anatomy at the State University of Iowa and then became a professor of comparative pathology at the University of Buffalo.