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CASTOR OIL
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See also:CASTOR OIL , the fixed oil obtained from the seeds of the castor oil plant or See also:Palma Christi, Ricinus communis, belonging to the natural See also:order See also:Euphorbiaceae. The botanical name is from See also:Lat. ricinus, a tick, from the See also:form and markings of the See also:seed. The plant is a native of tropical See also:Africa, but it has been introduced, and is now cultivated in most tropical and in the warmer temperate countries. In See also:size it varies from a shrubby plant to a See also:tree of from 3o to 40 ft. in height according to the See also:climate in which it grows, being arborescent in tropical latitudes. On See also:account of its very large beautiful palmate-peltate leaves, which sometimes measure as much as 2 ft. in See also:diameter, it is cultivated as an ornamental plant. In the See also:south of See also:England, with the See also:habit of an See also:annual, it ripens its seeds in favourable seasons; and it has been known to come to maturity as far See also:north as See also:Christiania in See also:Norway. See also:Plants are readily grown from seed, which should be sown singly in small pots and placed in See also:heat See also:early in Mardi heyoung plants are kept under See also:glass till early in See also:June when they are hardened and put out. The See also:fruit consists of a three-celled See also:capsule, covered externally with soft yielding prickles, and each See also:cell develops a single seed. The seeds of the different cultivated varieties,,of which there are a See also:great number, differ much in'size and in See also:external markings; but See also:average seeds are of an See also:oval laterally compressed form, with their longest diameter about four lines. They have a shining, See also:marble-See also:grey and See also: The oil is obtained from the seeds by two See also:principal methods—expression and decoction-the latter See also:process being largely used in See also:India, where the oil, on account of its cheapness and abundance is extensively employed for See also:illuminating as well as for other domestic and medicinal purposes. The oil exported from See also:Calcutta to See also:Europe is prepared by shelling and crushing the seeds between rollers. The crushed See also:mass is then placed in hempen cloths and pressed in a See also:screw or See also:hydraulic See also:press. The oil which exudes is mixed with See also:water and heated till the water boils, and the mucilaginous See also:matter in the oil separates as a scum. It is next strained, then bleached in the sunlight, and stored for exportation. A considerable quantity of castor oil of an excellent quality is also made in See also:Italy; and in See also:California the manufacture is conducted on an extensive See also:scale. The following is an outline of the process adopted in a Californian factory. The seeds are submitted to a dry heat in a See also:furnace for an See also:hour or thereby, by which they are softened and prepared to See also:part easily with their oil. They are then pressed in a large powerful screw-press, and the oily' matter which flows out is caught, mixed with an equal proportion of water, and boiled to purify it from mucilaginous and albuminous matter. After boiling about an hour, it is allowed to cool, the water is See also:drawn off, and the oil is transferred to See also:zinc tanks or clarifiers capable of holding from 6o to too gallons. In these it stands about eight See also:hours, See also:bleaching in the See also:sun, after which it is ready for storing. By this method too lb of See also:good seeds yield about 5 gallons of pure oil. Castor oil is a viscid liquid, almost colourless when pure, possessing only a slight odour, and a mild yet highly nauseous and disagreeable See also:taste. Its specific gravity is •96, a little less than that of water, and it dissolves freely in See also:alcohol, See also:ether and glacial acetic See also:acid. It contains palmitic and several other fatty acids, among which there is one—ricinoleic acid—peculiar to itself. This occurs in See also:combination with See also:glycerin, constituting the greater part of the bulk of the oil. The active principle to which the oil owes its purgative properties has not been isolated. It is, indeed, probable that it is formed in the See also:intestine, as a result of some decomposition as yet unknown. The dose is from a drachm to an See also:ounce. The pharmacopoeial mixture is best avoided, being almost uniquely nauseous. By far the best way to administer the oil is in capsules. It acts in about five hours, affecting the entire length of the bowel, but not increasing the flow of bile except in very large doses. The mode of its See also:action is unknown. The oil will purge when rubbed into the skin or injected per rectum. It is an invaluable See also:drug in temporary See also:constipation and whenever a mild action is essential, as in pregnancy. It is extremely useful for See also:children and the aged, but must not be employed in cases of chronic constipation, which it only aggravates, whilst relieving the symptoms. Additional information and CommentsThere are no comments yet for this article.
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