656 OLIVE OIL 



in medicine can be got ; the leaves are bitter, astringent, and 

 tonic ; the olives are oval, succulent, purple drupes, about 

 the size of damsons, and containing a single seed. The ripe 

 pericarp yields about 70 per cent, of oil, of which the finest, 

 imported from Provence and Florence, is obtained by 

 moderate pressure of the freshly-gathered fruit. Inferior 

 qualities are got from stale or damaged fruit, or by extra 

 pressure of the pulp. 



PROPERTIES. Olive oil is one of the fixed, fatty, or ex- 

 pressed oils which produce on paper or linen a greasy stain, 

 not removed by heat, and are glycerides of an acid radicle, 

 oleic, palmitic, or stearic acid, and the basic glyceryl. 

 Olive oil contains about 72 per cent, of olein or tri-olein, 

 C 3 H 5 (C 18 H 33 2 ) 3 , together with about 28 of palmitin and 

 allied fatty matters. It is of the consistence of syrup, 

 unctuous, transparent, odourless, and of a bland taste. 

 When pure it is pale greenish-yellow ; when impure, yellow 

 or brown. Specific gravity 0-914 to 0'919. At 50 Fahr. 

 it is liable to become of a pasty consistence ; and at 32 

 Fahr. to form a solid granular mass. It is not miscible with 

 water, is scarcely soluble in alcohol, but dissolves in one 

 and a half parts of ether. It is a capital solvent for cantha- 

 ridin, yellow phosphorus, atropine, and morphine. Ex- 

 posed to air, it oxidises, thickens, and slowly becomes rancid, 

 but does not dry up. It is often adulterated with purified 

 cotton-seed oil, in fact this cheaper product is probably 

 often sold as olive oil. 



ACTIONS AND USES. Olive oil is nutrient, laxative, and 

 emollient. Like other bland oils, small quantities are easily 

 digested and assimilated, aid cell development, and by oxi- 

 dation support animal heat. Larger quantities, such as one 

 to two pints for horses and cattle, and two to three ounces 

 for dogs, are laxative. An ounce each of olive oil and castor 

 oil form a mild laxative for the dog. Like other fluid fats, 

 when injected into the veins, it fatally obstructs capillary 

 circulation. Half an ounce injected into the jugular speedily 

 destroys a dog. As a demulcent and emollient, it is used in 

 poisoning by irritants and corrosives ; it antagonises the 

 action of alkalies by forming soaps, and retards solution 

 and absorption of arsenic. Olive oil, in small doses, is 



