Friction and shampooing are valuable accessories to bathing, and serve, as it were, to take the place of exercise in those diseases in which the patient is unable to exercise his body thoroughly for himself. Friction is applied to the skin merely to rub off the surface layers of epithelium, to encourage the dilatation of the superficial vessels, and the transudation of the sweat. Shampooing is a deeper and more forcible kind of friction, in which the rubber kneads the muscles and allows his fingers to press steadily upon and between them. This acts as a stimulant to the muscles themselves, much in the same way, but in a far milder degree, as an electric battery acts upon them. It must be borne in mind, however, that friction and shampooing are both exhausting, and must not be used to excess. While a patient is being shampooed, he involuntarily resists the pressure of the shampooer, and we have seen a patient reduced to a state of considerable exhaustion, after having been for twenty minutes in the hands of a professional rubber. It is not necessary to make any remarks on the subject of soaps. Their name is Legion, and the bather, guided by the light of common sense, may make his choice. The ancients were accustomed to anoint their bodies with a variety of smegmata, unguents and oils, both during and after bathing. As to the temperature of the bath and its duration, although these are both very important questions, it is impossible to lay down any exact rules, for they must be settled according to the condition of the bather. A physician, in ordering a course of baths for an invalid, should state, in writing (in the form of a prescription) the frequency, variety, temperature, and duration, as well as the time of day at which they are to be taken. After a hot bath it is sometimes necessary to arrange that a weakly patient shall go to bed for a couple of hours or more. To slake the thirst, both during and after a bath, there is nothing better than pure water. CHAPTER III. BATHING LOCALITIES.