Olivae Oleum-Olive Oil.-The oil expressed in the south of Europe from the ripe fruit of Olea europaea.

Characters.-Pale yellow, with scarcely any odour, and a bland oleaginous taste; congeals partially at about 36°.

Composition.-Olive oil consists of 72 per cent. of a fluid oil, olein, and 28 per cent, of a solid oil or stearoptene, palmitin. These are compounds of a base, glyceryl (C3H5), with oleic acid (C19H34O2), and palmitic acid (C17H31C2) respectively. Dose, 1/2 to 1 fl.oz.

Preparations. Many Plasters, Liniments, Ointments, Enema Magnesias Sul-phatis, Charta Epispastica, and Cataplasma Lini. It is also the source of the Soaps and Glycerine.

Sapo Durus,-Hard Soap. Made with Olive Oil and Soda.

Preparations.

a. Emplastrum Cerati Saponis.

b. Emplastrum Saponis.-1 in 7 1/6.

c. Linimentum Potassii Iodidi cum Sapone.-See Iodum.

d. Linimentum Saponis.-1 in 10.

Contained in Linimentum. Opii.

e. Pilula Saponis Composita.-Opium, 1/2 oz.; Hard Soap, 2 oz.;

Water, q.s. See Opium.

Hard Soap is also used in the preparation of many pills, several plasters, and Extractum Colocynthidis Compositum.

Sapo Mollis.-Soft Soap. Made with Olive Oil and Potash. Sapo Mollis is contained in Linimentum Terebinthinae.

Action And Uses. 1. Immediate Local Action And Uses

Externally applied, olive oil renders the skin smoother softer, and more flexible. It is used to facilitate friction over enlarged bones, or stiff joints; and in the form of liniments, to bring active bodies, such as ammonia and lime, more thoroughly into contact with the surface in a mild form. It is also an excellent mechanical application to burns and certain skin diseases, by coating the surface and excluding air, and in the treatment of the effects of corrosive acids and alkalies. Inunctions with olive oil to which 1/40th part of carbolic acid has been added, should be ordered in the desquamative stage of scarlet fever, as a disinfectant measure. Oil rubbed into the skin is absorbed by the lymphatics, and has a distinctly nutritive effect, of which use may be made in wasted children when the stomach rejects food.

Internally, oils may be similarly given in corrosive poisoning. In the stomach they are not specially changed; in the intestines they are partly emulsified, partly saponified, their glycerine being set free, and their fatty acid combining with free alkalies to form soaps. The molecular basis of the chyle is thus increased by this emulsion and soapy compound. In many persons excess of oil causes dyspepsia and loathing, especially in warm weather; and in most subjects some relaxation of the bowels or diarrhoea. As an Enema, olive oil is laxative, and is used in obstruction of the bowels.

2. Action In The Blood, Specific Action And Uses

Olive oil enters the blood from the lacteals or lymphatics, and may be traced in it if given in excess. Thence it enters all the cells of the body, especially those of the connective tissues, the amount varying with a number of circumstances. Here it is fully oxydised into carbonic acid and water, and constitutes one of the kinds of food, increasing the amount of fat in the tissues, furnishing force, and thus saving the waste of nitrogenous tissue and the necessity of consuming quantities of nitrogenous food, but unable of itself to support life.

Oils and fats are used in many forms (olive and other vegetable oils, butter, cream, cod-liver oil, etc.), in wasting diseases, such as scrofula and phthisis, as is fully discussed under Oleum Morrhuoe, page 379. Olive oil is rarely used in this country, but may be taken by some patients, in the form of sardine oil, when cod-liver oil is rejected.

3. Remote Local Action

Oils are excreted as carbonic acid and water, but excess will appear unchanged in the urine. It is not a special renal irritant like linseed oil.