DEPILATORY (Lat. depilo, to pull out the hair), any application for removing hair from the human skin without injuring its texture. Depilatories act either mechanically or chemically. The former are commonly mere plasters of pitch and resin, which, by their adhesive property, bring away the hair from the surface to which they have been applied. The true depilatories act by penetrating the pores of the skin, and destroying the bulbous roots of the hairs. Of these there are several kinds; but none can be compared for efficacy to the celebrated Oriental rusma, which is prepared as follows:—
"Mix two ounces of quicklime with half an ounce of orpiment or realgar (sulphuret of arsenic); boil that mixture in one pound of strong alkaline lye, then try its strength by dipping a feather into it, and when the flame falls off the rusma is quite strong enough. It is applied to the skin by a momentary friction, followed by wash-
ing with warm water. Such a caustic liquid should be used with the greatest circumspection, beginning with it somewhat diluted. A soap is sometimes made with lard of the above ingredients; or soft soap is combined with them: in either case to form a depilatory pomade. Occasionally one ounce of orpiment is taken to eight ounces of quicklime, or two to twelve, or three to fifteen; the last mixture being of course the most active. Its causticity may be tempered by the addition of one-eighth of starch or rye flour, so as to form a soft paste, which being laid upon the hairy spot for a few minutes, usually carries away the hairs with it. The rusma should never be applied but to a small surface at a time, for, independently of the risk of corroding the skin, dangerous consequences might ensue from absorption of the arsenic."—(Ure's Diet. of Arts, &c.)
However, a safer, and very effectual depilatory, is formed by impregnating cream of quicklime with sulphuretted hydrogen.