Source, Etc

The drug that is known by this name consists of the dried preputial follicles of the beaver, Castor fiber, Linne (Phylum Chordata, Class Mammalia, Order Rodentia).

The beaver inhabits principally the Hudson's Bay Territory, but is found also in western Russia, in Siberia, and elsewhere, living chiefly, if not entirely, upon vegetable matter, such as roots, bark, etc, of trees.

The generative organs of the beaver are concealed in a hollow or cloaca. Into the preputial (or vaginal) canal there open two large glands, one on each side. These glands, cut from both male and female animal and dried, form the commercial drug. In the fresh state they contain a whitish or yellowish creamy substance, but as they dry this becomes dark in colour. Our supplies are derived almost entirely from the Hudson's Bay Territory.

Description

The dried glands are of a dark-brownish or greyish colour, pear-shaped, and about 8 to 10 cm. long. They are frequently connected in pairs by a portion of the preputial or vaginal canal which has been cut away with them. They are firm, heavy, and solid, and possess a characteristic, empyreumatic, and not altogether agreeable odour. They contain a brown or reddish brown resinous secretion, in which, under the microscope, spherical grains of crystalline calcium carbonate can be detected, often in considerable quantity. The secretion varies much both in quantity and appearance, being sometimes pale in colour and soft, sometimes hard and dark.

FIG. 249.   Sexual organs of male Beaver, showing the position of the two castor sacs, c, communicating by a common aperture with the preputial canal. The latter and one of the castor sacs have been opened. t, testicle; u, urethra; c, castor sacs; g, gland of penis; p, penis; r, rectum; a, anus; e, anal gland; d, aperture of anal gland; o, preputial orifice; f, undersurface of tail. (Moeller, after Brandt.)

FIG. 249. - Sexual organs of male Beaver, showing the position of the two castor sacs, c, communicating by a common aperture with the preputial canal. The latter and one of the castor sacs have been opened. t, testicle; u, urethra; c, castor sacs; g, gland of penis; p, penis; r, rectum; a, anus; e, anal gland; d, aperture of anal gland; o, preputial orifice; f, undersurface of tail. (Moeller, after Brandt).

Constituents

The composition of the resinous secretion appears to be subject to great variation, due probably to the age of the animal, the time of year at which it was killed, and the time the drug has been kept. The amount of moisture present may be as much as 40 per cent., resinous matter soluble in alcohol about 40 to 70 per cent., fatty matter soluble in ether about 8 per cent. Salicin, benzoic acid and a crystalline substance, castorin, are also said to be present, but these statements require confirmation. The characteristic odour is due to a volatile oil.

Uses

Castor has long been used in the treatment of hysteria and dysmennorhoea; it also has an action on the heart, and is used in certain forms of heart-disease.

Varieties

Russian castor, formerly more highly esteemed than the American, is now very rarely imported. It resembles the American, but has a more agreeable, less empyreumatic odour.

Adulterants

Adulteration has been recently effected by emptying the castor sac and filling it with brown wood fibre. Pods thus adulterated are much lighter in weight than the genuine.