HOT-AIR BATH.—A bath in which the body, or part of the body, is exposed to the action of hot air for the purpose of inducing perspiration. In the so-called " Turkish bath " several connecting rooms are heated at varying temperatures, from 104° F. to 14o° F., the bather remaining for some time in each room, so that his body is gradually brought into profuse perspiration. The bather is then given a cold shower-bath and massage, whereupon he rests upon a couch, wrapped in blankets. This form of bath is very exhausting, and should be indulged in only by strong individuals. The fact that the head of the bather is also exposed to the hot air is an objectionable feature, which may cause disagreeable consequences. Persons suffering from disorders of the lungs, of the heart, or of the brain, spinal cord, or nerves, cannot be cautioned too earnestly against taking these baths. Hot-air baths, however, are to be preferred to STEAM-BATHS (which see), because in the former the body is actually made to perspire, whereas in the latter the steam is merely precipitated upon the skin of the bather. In the following will be mentioned some forms of hot-air bath apparatus : In the box-bath a box similar to that shown under STEAM-BATH is used, the air being heated by means of a closed steam-radiator from which the steam cannot escape. The head of the bather is outside the box. The air may be heated from 120° to 140° F., but patients should be cautioned against too high temperatures. In most cases a temperature of 12o° to 130° F. will be sufficient to induce perspiration, if the precaution be taken to heat the box before the patient enters it. Attendants are often in the habit of heating the air in the box to a temperature of 140° F., or over, con
trary to the fact that they know better. It is true that the human body will submit to many things, and that the skin affords good protection, but a temperature of 130° F. is sufficient to change vital organs ; and hot-air baths, are, therefore, not devoid of danger. The duration of the hot-air bath should be from ten minutes to half an hour, and a cold compress to the head is useful while in the bath. The bath should be followed by a cold douche or by a cold bath ; or, if after-perspiration is required, the entire body should be wrapped in woollen blankets for from half an hour to one hour, and massaged.
Local hot-air baths may be administered to the different parts of the body, such as the chest, the abdomen, the shoulders, the hips, or the limbs. For this purpose special apparatus have been constructed, which consist of boxes made of wood or of waterproof canvas, the openings of which lit the body snugly. The air in such an apparatus is heated by a gas or alcohol lamp with a tin chimney, the upper end of which runs into the apparatus (see Fig. 230). Local hot-air baths are used especially in joint-affections, gout, arthritis deformans, and rheumatism, and also in painful nervous affections. After the bath lukewarm sponging, cold douches, and massage are to be recommended.
Special apparatus are made in which the air, by means of electrical appliances, may be heated to a very high temperature (20o" F. or over). These apparatus, called electrotherms, are more or less successfully employed in obstinate affections of the joints. They require the use of special con trivances to protect the skin from burns.