Tepid Baths. - These baths range from 85° F. to 65° F. or 29.4° C. to 18.3° C. They are chiefly used for cleansing purposes, and at the lower margin of about 65° F. they may be used for a somewhat tonic action in persons of feeble circulation (p. 461).

Warm Baths. - These range from 97° F. to 85° F., or 36.1° C. to 29.4° C. When the water is above these temperatures it forms a hot bath. The warm water softens the epidermis, and is thus of much use in chronic skin-diseases. It dilates the vessels of the surface of the body, and thus tends to lessen any internal congestion. At the same time it tends to induce perspiration. On this account the warm bath is useful in lessening pain depending on congestion of internal organs and in preventing congestion from going on to inflammation. It is therefore very serviceable when there is a threatening of bronchitis, or gastro-intestinal catarrh, colic, etc. It tends to reduce the temperature both by dilating the peripheral vessels and inducing perspiration, and is therefore useful in febrile conditions. By withdrawing blood from the brain it tends to induce sleep.

1 Stephan, Allg. med. Central-Ztg., No. 87, 1884.

Hot Baths. - These range from 97° F., or 36.1° C, upwards. A much higher temperature than can be endured at first can be borne if the temperature be gradually raised by the gradual addition of hot water to the bath while the body is immersed, and the bath may thus be raised as high as 110° F. Hot baths not only prevent loss of heat from the surface, but if above the temperature of the blood, actually impart heat to the body. The consequence of this is that the temperature of the body rises very rapidly, and therefore the respiration and pulse both become very quick. The peripheral vessels become still more dilated than in the warm bath, and the blood pours so rapidly through them that, in spite of the quick and powerful action of the heart, there may be a tendency to syncope when the head is raised. After remaining in such a bath from ten to twenty minutes, the patient must be carefully lifted out so as to avoid any risk of syncope, and should be wrapped in warm, dry blankets. The hot bath is a still more powerful agent than the warm bath in producing sweating, and is employed in cases of dropsy.

Hot Foot-bath. - A hot foot-bath has a general effect that can hardly be explained by the simple dilatation of the vessels in the feet and consequent derivation of blood to them. It seems, indeed, to exert some reflex action on other parts of the body and causes a general feeling of warmth. It is very useful as an adjunct to vascular stimulants in relieving congestion and preventing inflammation, as in threatened catarrh, bronchitis, etc. When the feet are put into a hot bath, we find that the femoral arteries become much dilated and pulsate much more vigorously than they did before. It is not improbable that this dilatation extends beyond the femoral to the iliac arteries, and that the supply of blood is increased in the pelvic organs as well as in the feet. In cases of amenorrhoea, especially where it has been brought on by exposure to cold, hot foot-baths tend to restore the menstrual flow. They should be begun four or five nights before the period is expected, and continued during the time it ought to last. Their efficacy may be increased by the addition of a little mustard.

Hot Sitz-baths. - These have a still greater tendency than hot foot-baths to increase the circulation in the pelvic organs, and they may be used either alone or with mustard in the manner just described in cases of amenorrhoea.

Poultices. - Poultices are simply a means of applying heat and moisture to a limited portion of the surface of the body. Their mode of action has already been discussed (p. 342). They consist essentially of some farinaceous substance made into a paste with hot water, and the most common substances used as bases are linseed meal, bread, bran, oatmeal or starch. In all cases, not only should the water with which the poultice is made be perfectly boiling, but the bowl in which it is to be mixed, the spoon with which it is to be stirred, and the tow or flannel in which it is to be laid, should all be as hot as possible. By adding the linseed meal to the water and constantly stirring, there is less chance of the poultice being knotty than if the water were added to the meal. If the poultice is intended to be applied to a wound, sore, boil, or carbuncle, it should be spread upon a piece of flannel or tow and applied directly to the skin, because the softening action of the water and oil it contains on the dermal tissues is required as well as the warmth. But where the poultice is used to relieve pain, congestion, or inflammation of the internal organs, as in pleurisy, pneumonia, or colic - intestinal, biliary, or renal, it ought not to be applied directly to the skin, but should be separated from it by something which conducts heat badly, such as flannel. The reason for this is that it is impossible to apply a very hot poultice directly to the skin on account of the pain it causes, whereas if a substance which conducts heat badly be interposed, the poultice can be applied boiling hot, the heat gradually passes through without becoming. inconveniently great, and is retained for a much longer time.

Fig. 157.   The upper figure represents the bag empty; the lower one the bag filled and sewn up.

Fig. 157. - The upper figure represents the bag empty; the lower one the bag filled and sewn up.

In order to accomplish this, a flannel bag should be prepared, a convenient size being twelve inches by eight; this should be closed at three edges and open at the fourth; one side of it should be about one inch or one inch and a half longer than the other, as represented in the diagram (Fig. 157), and it is convenient also to have four tapes attached at the points which form the corners when the bag is closed, in order to keep the poultice in position. Besides this, another strip of flannel should be prepared of the same breadth as the length of the bag, and long enough to wrap round it once or oftener. Crushed linseed, bowl, and spoon should then be got together, and the spoon and bowl thoroughly heated by means of boiling water; the poultice should then be made with perfectly boiling water, and rather soft. As soon as it is ready it should be poured into the bag, previously warmed by holding it before the fire; the flap which is formed by the longest side of the bag should now be turned clown and fastened in its place by a few long stitches with a needle and thread; it should then be quickly wrapped in the strip of flannel (also previously warmed), and fastened in situ, if necessary, by means of the tapes. It may be covered outside with a sheet of cotton wool.