There are various modes of applying artificial heat. It may be dry or moist.

Moist Heat

The Vapor-Bath.—It consists simply in the application of the vapor of water to the surface of the body. Sufficient attention, for the limits of this work, has been bestowed on this subject in the article on "Hydrotherapy."

Dry Heat

To the general surface of the body dry heat may be applied by simply raising the temperature of the air of the apartment, the body being uncovered. Local application of dry heat may be made to any part by means of woolen cloth, earthen plates, sad-irons, bags of salt, bricks, etc., heated to the proper temperature. The effects of these applications depend largely on the amount of heat contained in these objects. They produce at first the sensation of warmth, redness of the skin, and may cause vesication, or deep-seated burning and destruction of the tissues.

The Turkish Bath

This differs from the Russian bath, in that it consists of dry air without the presence of the vapor of water. The human body can exist in dry air at a very high temperature, without injury, for a short period, provided it is in a state of health. The temperature of the air of the Turkish bath ranges from 95° Fahr. to 160° Fahr., but the highest point is attained at the conclusion of the process. There are usually three apartments, so that the patient passes from one grade of temperature to another, and thus avoids the unpleasant, even dangerous, effects of high heat suddenly applied. When the temperature reaches 110° Fahr., already some distress is experienced. As the heat increases, the breathing becomes short, hurried, and labored; the action of the heart is tumultuous; an unpleasant sensation of heat and irritation, with itching, is felt over the whole body; the head has a feeling of fullness, with constriction of the forehead and ringing in the ears; perspiration soon begins, and, when the temperature reaches the highest point, is very profuse.

It is obvious that a decided impression is made on the organism by a Turkish bath. The first effect of the heat is on the sensory nerves— the impression of warmth. The peripheral vessels dilate, and, of course, admit into them a larger amount of blood, with the effect to diminish the amount of blood in the internal organs. The temperature of the blood rises with the increase of heat; the action of the heart corresponds, and a state of fever would be quickly induced if the excess of heat were not at once disposed of by the perspiration, in which, according to the doctrine of the correlation of forces, it disappears as motion. The circulation being more rapid, and the peripheral vessels containing more blood, a more active metamorphosis of tissue probably takes place. Elimination is more active through the skin, but is less active through the intestinal canal and the kidneys. The acidity of the urine is increased, and the water and salts are relatively diminished. Remotely, the tension of the vascular system falls, absorption becomes more active, the muscular tonus declines, and the sensibility of the nervous system and of the special senses is lowered.