*Effects of Heat and Cold Sensations.*—Sensations, or feelings, of heat and cold are made possible through the nerves which connect the brain with the _temperature corpuscles_, found in the skin (page 343). As the warm blood recedes from the skin, a sensation of cold is felt, but when the blood returns, there is again the feeling of warmth. The sensation of cold prompts one to seek a warmer place, or to put on more clothing; while the sensation of heat, if it be oppressive, leads to activities of an opposite kind. Prompted in this way by the sensations from the skin, one voluntarily supplies the external conditions, such as clothing and heat, that affect the body temperature. *Alcohol and the Regulation of Temperature.*—Alcohol, through its effect upon the nervous system, interferes seriously with the regulation of the body temperature. By dilating the capillaries, it increases the circulation in the skin and leads to an undue loss of heat. At the same time the excess of blood in the skin causes a _feeling of warmth_ which has led to the erroneous belief that alcohol is a heat producer. If taken on a cold day, it deceives one about his true condition and leads to a wasting of heat when it should be carefully economized. Not only is alcohol of no value in maintaining the body temperature, but if taken during severe exposure to cold, it becomes a menace to life itself. Arctic, explorers and others exposed to severe cold have found that they withstand cold far better when no alcohol at all is used.(92) HYGIENE OF THE SKIN Much of the hygiene of the skin is included in the problems of keeping it warm and clean. It is kept warm by clothing; bathing is the method of keeping it clean. *Clothing* should be warm and loose-fitting. Woolen fabrics are to be preferred in winter to cotton because, being poorer conductors of heat, they afford better protection from the cold. But wool fails to absorb the perspiration rapidly from the skin and to pass it to the outside where it is evaporated. This, together with its tendency to irritate, makes woolen clothing somewhat objectionable for wearing next to the skin. This objection, however, is obviated by woolen underwear which is lined by a thin weaving of cotton.