The Physiomedical Dispensatory by William Cook, M.D., 1869
This oil is obtained from the fruit of the Olea Europea, or olive tree now common to the shores of the Mediterranean. This tree is usually from fifteen to twenty feet high; with evergreen, lanceolate leaves two to three inches long, and small white flowers in axillary clusters. The fruit is a small oval drupe, of a peculiar greenish (olive) color, three-fourths of an inch long, and with a fleshy pericarp. This pericarp abounds in a fixed oil, which is obtained by pressure. The finest kind is obtained by lightly crushing the fruit that is gathered before it is perfectly ripe, and letting the oil separate spontaneously. Only a moderate quantity is thus obtained, and is mostly used in Europe. Afterwards, the olives are beaten to a paste in a mill, allowed to stand for two or three days, and then subjected to only a moderate pressure. This is called virgin oil, and has a greenish tinge. For the ordinary oil of commerce, the olives are gathered when fully ripe, (and the marc left after the virgin oil is obtained, is also used,) crushed and mixed with boiling water, and then submitted to moderate pressure, the oil being removed from the surface after a few hours. This process yields a quality only a little inferior to the virgin oil. The coarser products, to be used in the manufacture of soaps and similar purposes, are obtained by breaking up the latter marc, adding water and allowing it to ferment for a few days, and then subjecting the mass to very strong pressure.
Olive oil is of a pale-yellowish, sometimes greenish, tinge, a bland and slightly sweet taste, and is nearly odorless, or else of a faint milky flavor. At a temperature of 38E F., it begins to congeal; and at the freezing point separates into a whitish concrete mass below and a limpid fluid above. This fact gives a convenient method for testing the purity of a sample; as it will not separate thus, at the freezing point, if adulterated with oil of poppies. Other oils, and especially lard, concrete considerably above the freezing point; and a mixture of poppy oil and lard does the samethe lard always becoming much solider than the congealed portion of olive oil. About one-third of the olive oil, or a little less, is concrete. Only a very small percentage is soluble in alcohol; but if congealed, as above, the liquid olein is readily soluble in alcohol. It is not a drying oil, but becomes thicker and rancid by exposure. This oil is refined for the watchmakers by immersing in a vial of it a strip of sheet-lead and placing the vial in the sun. The oil by degrees gets covered with a curdy mass, which after some time settles to the bottom, while the oil becomes limpid and colorless, and is then decanted into another vial.
Properties and Uses: This oil is pleasant and bland, somewhat nutritious, and mildly laxative. For infants it is especially serviceable as a cathartic, being easily taken and of mild action. It is suitable also for adults in irritated or inflamed conditions of the bowel or stomach , and may be given after acrid poisons. Externally, it is lubricant, and is valuable for shielding irritated surfaces, relax contracted tendons, and promote healing. For these purposes, it is either made the basis in which to incorporate medicaments, or is compounded with dense fatty or resinous substances to give them pliancy in the formation of ointments, cerates, or plasters. Sometimes it is used in laxative enemata. Dose as a laxative, one to two fluid ounces; for a child one year old, two teaspoonfuls or less.
Medical Herbalism journal and medherb.com