Castoreum. Castor. The follicles of the prepuce of the Castor Fiber, Beaver, filled with a peculiar secretion; dried and separated from the somewhat shorter and smaller oil-sacs, which are frequently attached to them; from the Hudson's Bay Territory.

Description. The follicles are in pairs, about 3 inches long, fig-shaped, firm and heavy, brown or grayish-black, and contain a dry resinous highly odorous secretion. The castor of commerce is of two varieties, the Russian and Canadian; the former is the most highly prized. This substance is secreted by a pair of membranous pear-shaped follicles, situated between the anus and external genitals, and united by a common duct to one another. It is a dark-coloured matter, of the consistence of putty, with a peculiar odour. In Russian castor, the sacs are larger, fuller, and have a stronger smell. In the Canadian variety, they are more or less wrinkled externally, and the contents inferior. The consistence of the contents varies with the amount of water present.

Prop. & Comp. Castor contains volatile oil, uric, phosphoric and benzoic acids, combined with potash, soda, and lime, also carbonate of ammonia, salicine, carbolic acid, and a peculiar principle, castorin. Its active properties are taken up by ether and alcohol; slightly by water; but they are decomposed by boiling for some time. The contents of the sacs should be in great part soluble in rectified spirit and ether.

Off. Prep. Tinctura Castorei. Tincture of Castor. (Castor, one ounce; rectified spirit, twenty fluid ounces. [Castor, two troy ounces; alcohol, two pints. U. S.] Prepared by maceration.)

Therapeutics. Castor is stimulant, and antispasmodic; hence it has been used in hysteria and epilepsy, and also to rouse the system in cases of an adynamic type, as in typhoid pneumonia.

Dose. In substance, 5 gr. to 15 gr.; of tincture, 1/2 fl. drm to 2 fl. drm.