CHAP. XXIV. Of Oils.
PRoperly and commonly we call oil that juice which is pressed forth of Olives; but the word is used more largely, for we call every juice of a fluxible, unctuous, and aiery sub∣stance, Oil. There are three differences of these oleaginous juices: The first is of those things which yield oil by expression, as well fruits as seeds being bruised, that by beating the oily juice may be pressed forth; some are drawn without fire, as oil of sweet and bitter almonds, oil of nuts, of Palma Christi. Others are made to run by the help of fire, by which means is gotten oil of bayes, linseed-oil, rape-oil, oil of hemp, and such like: The manner of drawing oil from seeds is set down by Mesue in his third book.
The second sort of those oils which are made by the infusion of simple medicines in oil, where∣in they leave their qualities: and this is done three several wayes, the first is by boiling of roots, leaves, tops of flowers, fruits seeds, gums, whole beasts, with wine, water, or some other juice, with common or any other oil, ••ntill the wine, water, juice be consumed, which you may perceive to be perfectly done, if yo•• cast••d op of the oil into the fire, and it maketh no noise but bur∣neth. It is to be remembre•• ••ha•• sometimes the seeds or fruits are for a certain time to be ma∣cerated before they are set to the fire; but it must be boiled in a double vessel, lest the oil par∣take of the fire.
After this manner is made oleum costinum, rutaceum, de croco, cydoniorum, myrtillerum, mastichi∣num, de euphorbio, vulpinum, de scorpionibus, and many others. The second is by a certain time of maceration, some upon hot ashes, others in hors-dung that by that moderate heat the oil might draw forth the effects of the infused medicines into it self. The third is by insolation, that is, when these or these flowers, being infused in oil, are exposed to the sun, that by the heat thereof the oil may change, and draw into himself the faculty of the flowers which are infused: of this kinde are oil of roses, camomil, dill, lilies, of water-lilies, violets, and others, as you may see in Mesue.
The third kinde is properly that of the Chymists, and is done by resolution made after divers manners, and of this sort there are divers admirable qualities of divers oleaginous juices, whe∣ther they be made by the sun or fire, or putrefaction, as we shall speak in his place hereafter.
We use oils when we would have the virtue of the medicament to pierce deep, or the substance of the medicines mingled with the oil to be soft and gentle. Moreover, when we prepare oils that should be of a cooling quality, the common oil of the unripe Olive is to be used: of that should the oil of roses be made.
Again, when we would prepare oils of heating qualities, such as are Oleum Philosophorum, or of Tiles, sweet and ripe oil is to be chosen.