Under this head, I include both liquid oils and fats, together with wax, as of closely analogous nature. Of the origin, preparation, and physical and chemical properties of these bodies, I shall say little or nothing; as they are generally well known, and if the reader desire information, he will find it in the U. S. Dispensatory.

Of the liquid oils, those usually employed are the olive oil and almond oil; of the fats, lard, suet, and spermaceti, including wax. Others are occasionally used; but none which produce effects different from those attainable through the particular substances above mentioned. Whatever may be popularly thought upon the subject, there is nothing peculiar or specific in the operation of goose grease, rabbit's fat, bear's grease, or even the fat, of serpents.