History. — This drug is a peculiar concrete substance obtained from the preputial follicles of the Castor Fiber, or Beaver. These follicles are filled with a thick fluid secretion, which slowly concretes when they are removed from the animal. Most of the castor of the present day is derived from the beaver of North America. It has much the appearance of a pair of dried testicles united by their spermatic chords, dark liver brown and wrinkled externally, paler liver brown internally, resinous in fracture, when perfectly dried of a strong, peculiar heavy odor, and of an aromatic, bitter, offensive taste. Rectified spirit is its best solvent ; though ether extracts a good part of its virtues.
The Russian castor, from the Russian dominions, is seldom seen in this country ; it may be distinguished from the American by being larger, fuller, heavier, and less tenacious, and by its stronger taste and smell. Treated with distilled water and ammonia, M. Kohli states that it affords a white precipitate, while the American throws down an orange-colored matter. Good castor has a strong, fetid, peculiar odor ; a bitter, acrid, and nauseous taste, and a color more or less tinged with red. It is composed of numerous salts, mucus, a volatile oil, a resinous substance, a horny matter, osmazome, and a peculiar crystalline, non-saponifiable principle called castorin. Age impairs the virtues of castor, which is hastened in an elevated temperature ; moisture promotes its rapid decomposition. It should always be kept in a dry cool place. It is not good if quite black, tasteless and inodorous. A factitious preparation is often sold, consisting of a mixture of various drugs, scented with genuine castor, intermixed with membrane, and stuffed into the scrotum of a goat. The feeble odor, want of other characteristic sensible properties, and the want of the smaller follicles containing fatty matter, and which are always attached to the genuine bags of castor, will enable one to detect the fraud.
Properties and Uses. — Moderately stimulant, antispasmodic, and emmenagogue. Used in hysteria, amenorrhea, epilepsy, and many anomalous nervous affections. Dose of the substance, from ten to twenty grains ; of the tincture, from half a fluidrachm to two fluidrachms.
Off. Prep. — Tinctura Castorei ; Tinctura Castorei Ammoniata.