In order that the skin may perform its functions properly, it must be perfectly clean, the pores must be kept open, and the sweat glands free to throw off all the effete matter and prevent its accumulation within the system. While soap and water are necessary and helpful, free perspiration induced by vigorous bodily exercise or artificial heat will also enable the glands to cast off the more solid substances which accumulate at the bottom.
An eminent French physician has discovered that the annoying odors from the skin which characterize certain persons have their seat in the bottom of the sweat sack, and can be successfully removed by free perspiration followed by a bath.
In addition to the general benefits to the health, of systematic, vigorous exercise and the bath, they will give freshness of color to the skin, prevent the coming of wrinkles, and give to the face a beauty such as no paint or powder can approximate. If ladies with sallow complexions and shrunken countenances would substitute exercise and bathing for facial massage, the benefits of which last only so long as its use is continued, the results would be much more satisfactory.
Many of the common diseases of the skin which destroy the beauty of the complexion are believed to be due to certain microbes. If the skin were kept, by exercise and bathing, in a thoroughly healthy condition, these microbes would find no lodgment, or, gaining a temporary foothold, would readily yield to judicious hygienic treatment.
The Hair and Nails.—These, properly considered, are appendages of the skin. The hair follicles are hollow receptacles, from the bottom of which the hair grows. Alongside each hair follicle are two glands, called the sebaceous glands, which provide the hair with a natural oil or grease, and prevent excessive dryness. This sebaceous matter tends to keep the skin flexible, and serves to protect both skin and hair from the acridity arising from perspiration. The hair serves as a protection, shielding the brain from extremes of heat and cold, and moderating the force of blows upon the head.
The nails not only serve as a protection to the ends of the fingers, but also enable us to grasp more firmly, and to pick up small objects. Well-kept nails contribute much to the beauty of the hand. They are not only an indication of cleanliness but also a mark of refinement.
The Perspiratory Glands.—The skin is provided with numerous sweat-glands which consist of very small tubes with globe-like coils at their deeper extremity. It is estimated that there are 2,800 of these glands to the square inch of the surface of the body.
These glands or pores of the skin are, day and night, constantly excreting a watery fluid. Ordinarily this evaporates as rapidly as it is formed, and the process is called insensible perspiration. Under the influence of heat or exercise the flow is more abundant, and appears upon the surface of the body in the form of minute, colorless drops. This is known as sensible perspiration.
This excretion consists of about ninety-eight parts of water and two parts of solid matter. The quantity of perspiration varies with the temperature, the occupation of the individual, and other circumstances. In an adult, the daily amount is about thirty ounces, or more than nine grains a minute.
Benefit of Perspiration.—Besides freeing the blood of a large amount of water, with the effete matter it contains, perspiration serves to reduce the temperature of the body. This function is most active in hot weather, and the cooling process is proportionally increased, thereby contributing to the comfort of the individual. A partial or temporary check of this excretion is usually attended with headache, fever, and other unpleasant symptoms, and its total interruption is fatal. For the purposes of experiment, rabbits and other small animals have been covered with a coating of varnish, and death invariably ensued in from six to twelve hours.