Castor Oil, a mild purgative obtained from the nuts of the castor oil plant, the ricinus communis or palma Christi. Ricinus is an apetalous genus of plants belonging to the natural order euphorbiaceae. It was originally a native of Asia, and was used by the nations of antiquity, but is now naturalized in Africa, America, and the south of Europe. The characters of this genus are: Leaves alternate, stipulate, palmate, glands at apex of petiole. Flowers in terminal panicles; monoecious, no petals; calyx 3-5 parted, valvate; filaments numerous, polyadelphous; style short, stigmas 3, bipartite, feathery; ovary globose, 3-celled, with an ovule in each cell; fruit capsular, tricoccous. The R. communis or palma Christi has peltate palmate leaves, with lanceolate serrated lobes; an herbaceous glaucous stem, of a purplish red color upward; and flowers in long green and glaucous spikes, springing from the divisions of the branches, the males from the lower part of the spike, the females from the upper. The capsules are prickly. It varies in size in different countries. In some parts of Europe it is not more than three or four feet high, but in India it is a tree, and in Spain it attains fair dimensions.
The native country of R. communis is unknown; it is conjectured to be Barbary. The castor oil plant was known in very ancient times, both to the Egyptians and the Greeks. The latter called it croton, a name bestowed by modern botanists on another genus of euphorbiaceous plants, one species of which yields the strongly purgative oil called oleum tiglii or croton oil. Numerous varieties of R. communis exist in various localities, differing not only in color and the peculiar condition of the stem, but in stature and duration. In warm countries it is ligneous and perennial; in cold regions, annual and herbaceous. The entire plant possesses active properties, but the oil | extracted from the seeds is alone employed in Europe. The ancients administered the seeds entire, but their variable action, producing sometimes even fatal effects, led to their disuse. The oil is of comparatively recent introduction. The seeds were formerly known in the shops as semina ricini or semina cataputim majoris. They are about the size of a small bean, obtuse at both ends, the surface being smooth, shining, and beautifully marbled. The skin consists of three tunics; the nucleus or kernel consists of an oily albumen and an embryo, the cotyledons of which are membranous or foliaceous.
The outer shell is devoid of taste. According to Dr. Dicrbach, the active principle resides in the inner coat; others assert that the purgative principle resides in the embryo. Merat and De Lens have shown in the Dictionnaire des sciences medicates, t. xlix., that the active principle is diffused through the entire substance of the kernel, though possibly with more intensity in the embryo. - The quality of castor oil depends on the greater or less maturity of the seeds, the peculiar variety of the plant from which they have been obtained, and the accidental or intentional admixture of other seeds before the process of extraction. Both in India and America much heat was formerly employed in the process, and this was injurious to the quality of the oil. During the application of heat a volatile principle escaped, which was so irritating that the workmen had to protect their faces by masks. The French method is the best. The fresh seeds are bruised, and then put into a cold press. The oil is expressed and allowed to stand some time, to permit the albumen, mucilage, and other matters to subside; or it is filtered, to separate them more rapidly. The produce is equal to about one third of the seeds employed, and the oil possesses all its natural qualities.
Both the French and Italian oils are much milder than oil procured from tropical countries. Oil of good quality is a thickish fluid of a very pale yellow color, the best being almost limpid, with a slightly nauseous odor and an oily taste, mild at first, but causing a feeling at the back of the throat, more or less intense, according to the freshness of the specimen. Bad oil is rancid and disagreeable. Castor oil is much used in the East, France, Italy, and other countries, for burning, as well as for medicinal purposes. - The cathartic action of castor oil seems to depend upon the development of an acrid principle, identical with or analogous to that of croton, modified by the much larger amount of bland oil with which it is associated. When pure, it is a mild and certain aperient or laxative, commonly operating without griping or other inconvenience, very soon after it is taken. It is deemed the most proper laxative in many inflammatory states of the abdomen, the kidneys, and the bladder. It is also deemed a most eligible medicine in piles and other affections of the rectum. Its use is liable to be followed by more or less constipation.
The chief objection to its use is its repulsive taste.
Castor Oil Plant.
From 15 to 20 drops of pure liquor potassrc will usually saponify half an ounce of castor oil, to which one ounce of distilled water and a drachm of spirits of pimento or of nutmeg may be added. This makes an emulsion which is effective and not unpleasant to the taste. The manufacture of castor oil is actively carried on in the United States, especially at St. Louis, the beans being produced in southern Illinois.