It has been said, with regard to the use of baths, that _cold stimulates, but heat facilitates function_. “Between the two therapeutic opposites,” says Braun, “a similar relation exists, as between winter and summer life, and between sea and mountain air. The physician who has, to a certain extent, acquired an insight into the diseased side of mankind, divides the chronically sick into two groups, the one consisting of individuals whose organism has sufficient capital to afford the strong reaction required, the other consisting of persons needing nice management, and whose own power cannot be exposed to any great demand. For the one there is the system of exercise, cold treatment, cold baths, sea baths, and sea air; for the second, indulgence, warm treatment, warm climate, warm baths, mountain air.” Seeing that both hot and cold baths increase the natural combustion of the body, it will be evident that persons undergoing a course of treatment by either method should be exceedingly careful that during the progress of their course of treatment the best fuel only is placed on the human furnace. They should eat the simplest and most nutritious food, and breathe nothing but the purest air. CHAPTER II. THE VARIETIES OF BATHS. The _tepid_ bath has a temperature of from 85° to 92° Fahr., the _warm_ bath a temperature between 92° and 98° Fahr., and the _hot_ bath a temperature of from 98° to 112° Fahr. The _cool_ bath has a temperature from 60° to 75° Fahr., and the _cold_ bath is of a temperature below 60° Fahr., downwards to the freezing point of water. Hot or cold water may be used locally. We are familiar with the hip-bath and foot-bath, and occasionally we meet with baths of a special shape, made for the reception of the arms or hands, in cases where their local treatment has been deemed necessary. Various plans have been devised for increasing the stimulating effect of water. One method of attaining this object is by keeping the water constantly in motion, as is done in the so-called _wave bath_, common in some parts of the Continent. Another way is by so increasing the size of the bath that the patient is able to move freely in it. In a big bath, not only is the good effect of exercise able to be added to that of bathing, but the concussion of the water on the surface of the body, and the constant change of the stratum of water in contact with the body vastly increases the power of the bath in influencing the temperature and stimulating the skin. The best of all baths is the _swimming bath_, for in it the bather can indulge in a free exercise of his limbs, such as is hardly attainable under any other circumstances. Swimming is a very valuable exercise, because it employs the arms equally with the legs, and leads to a healthy development of the muscles of the chest. Nearly all good swimmers are big chested.