The skin plays an important part in eliminating waste products from the system. It does this by means of the sweat-glands, which are found scattered all over the body. These glands have small ducts, ending in minute apertures on the surface of the skin. If these apertures are allowed to become blocked up, either by dirt or by the natural grease of the body, the skin cannot carry out its duties. The result is that a certain amount of this waste matter is kept back, and the health suffers in consequence sooner or later. [Sidenote: Hot baths.] Neither cold baths nor outdoor bathing can get rid of this grease, so that a hot bath occasionally is essential, even in the case of people who bathe regularly every morning, either at home or out of doors. The usual objection to hot baths is that people take cold unless they go straight to bed as soon as they have dried themselves. Otherwise, so they say, they go on perspiring and take a chill. Now this is due, not to their having had a hot bath, but because the water was not hot enough when they got out of it. Hot water has the same effect as cold in bracing up the sweat pores, and preventing them from continuing to pour out unnecessary perspiration. Lukewarm water, on the other hand, leaves the skin lax and moist, and it is then that people are liable to chills. Hence the popular idea of running in some cold water before the bath is finished is a mistake, as it brings about the very conditions we are anxious to avoid. An indispensable adjunct to every bathroom is a thermometer, by which the temperature of the water can be accurately gauged. The common plan of testing it by the hand is fallacious, as the result depends largely on the state of the hand at the time. If the fingers are cold when dipped in, the water feels warmer than it usually is, and _vice versa_. The best temperature at which to take a hot bath is 100°F. or just below that. If more water is added afterwards it should be hot, not cold, so as to maintain the temperature at the same level. With the aid of these precautions it will be found that drying is a simple process, and the skin is left in a delightful state without any undue perspiration to follow. So far from causing a liability to chills, it is perfectly safe to emerge from a bath of this sort and take a walk immediately after dressing, even on a winter’s day, without suffering from any ill-effects. People sometimes complain that a hot bath makes them feel faint. This is due to the steam, not to the water itself. If the windows are kept open this discomfort may be entirely avoided.