c. (Ph. E.) When olive oil is “carefully mixed with 1⁄12th part of its volume of a solution of 4 oz. of mercury in 8 fl. oz. 6 dr. of nitric acid (sp. gr. 1·500), it becomes in 3 or 4 hours like a firm fat, without any separation of liquid oil.”
d. M. Pontet recommends the mercurial solution to be made by dissolving 6 parts of mercury in 71⁄2 parts of nitric acid (sp. gr. 1·35), without heat; of this solution he adds 1 part to every 48 parts of the oil, and well shakes the mixture every 30 minutes, until it begins to solidify. This it does after about 7 hours in summer and 4 or 5 hours in winter, and when the oil is pure it will have formed, in 24 hours, a mass so hard that some little force must be employed to thrust a glass rod into it. The other edible oils do not furnish a hard mass with nitrate of mercury. The solidity of the mass is exactly in proportion to the quantity of foreign oil present. When
the sophistication is equal to 1-8th of the whole, a distinct liquid layer separates; when the mixture contains half its volume of an inferior oil, one half only of the mixture becomes solid, and the other half continues liquid. A temperature of about 90° Fahr. is the best to cause the oil and coagulum to separate perfectly from each other. When the oil has been adulterated with animal oil, the mixture solidifies in about five hours; but in this case the coagulum consists of the animal oil, whilst the olive oil floats on the surface, and may be decanted for further examination. This coagulum, on being heated, exhales the well-known odour of rancid fat or melted tallow.
e. Dr Ramon Cordina Langlies states that the best reagent for the examination of olive oil is that of Hauchecorne.
This reagent is composed of three parts of pure nitric acid at 40° with one part of distilled water. The following is Dr Langlies’ process for proving that olive oil does not contain seed oil, and more especially cotton oil:—
He mixes three grammes of the oil to be tested with one gramme of the reagent in a test tube, or a small stoppered flask, and heats the liquid in a water bath. If the oil is pure the mixture becomes clearer, and takes a yellow colour, like purified oil; if it is adulterated with seed oil, it acquires the same transparency as the pure oil, but becomes red. With 5 per cent. of seed oil the reddish colouring is characteristic; with 10 per cent. it is decided. The reaction does not require more than from 15 to 20 minutes.
The colouring of the oils lasts for three days.
Uses, &c. The dietetical uses of olive oil are well known. In Spain and Italy it is commonly employed as a substitute for butter. It is highly nutritious, but is digested with difficulty by some persons, and hence should be avoided by the dyspeptic. Like almond oil, it is occasionally employed as a laxative and vermifuge, and is, perhaps, one of the mildest known. In pharmacy it is extensively employed in the preparation of cerates, liniments, ointments, and plasters.—Dose. For an adult, 1⁄2 to 1 wine-glassful as a mild aperient; for an infant, 1⁄2 to 1 teaspoonful, mixed up with an equal quantity of honey, syrup of roses, or syrup of violets. The white fibrous sediment which forms in the recently expressed oil is the ‘AMURCA’ of Pliny, and was formerly highly esteemed in medicine.
Oil, Olive, Droppings. Syn. Sweet-oil d. The ‘foots’ or ‘deposits,’ and the ‘drippings’ of the casks, cisterns, and utensils. Used for machinery, making soap, &c.
Oil, Olive (Oxygenated). Syn. Oleum olivæ oxygenatum (Ph. Batav.), L. Olive oil, 16 oz., is placed in a receiver surrounded with ice or very cold water, and chlorine is slowly transmitted through it for several days, or until