FRICTION, in Medicine and Surgery, denotes the act of rubbing a diseased part with oils, unguents, or other matters, in order to ease, relieve, and cure it. Frictions are much used of late in venereal cases. They prefer the applying of mercury externally by way of friction, to that of giving it internally, to raise a salivation.
There are also frictions with the flesh brush, a linen cloth, or the hand only. These frictions are a sort of exercise which contributes greatly to health; as they excite and stir up the natural warmth, divert defluxions, promote perspiration, open the pores of the skin, and carry off stagnant humours.
The flesh brush (Dr Cheyne observes) is an exercise extremely useful for promoting a full and free perspiration and circulation. Every body knows the effect of currying horses; that it makes them sleek, gay, lively, and active; so as even to be judged equivalent to half the feeding. This it can no otherwise effect, but by assisting nature to throw off the secretions of the juices, which stop the free circulation, and, by constant friction, irritation, and stimulation, to bring the blood and spirits to the parts most distant from the seat of heat and motion; and so plump up the superficial muscles. And the same effect it would have in other creatures, and man himself, if managed in the same manner, and with the same care and regularity. Persons,
Persons, therefore, of weak nerves and sedentary lives, would do well to supply the want of other exercise with spending half an hour, morning and night, in currying and rubbing their whole body, especially their limbs, with a flesh brush. But this means of health is most advantageously used when the prime viæ are most empty.