Syst. Nat Gmelin. 124. D. 1. Mammifera. Ord. 4. Rodentia. Cuvier. G. 23. Fore-teeth in the upper jaw truncated, hollowed with a transverse angle; in the lower, transverse at the point. Grinders in both jaws four. Tail long, depressed, flat, horizontal, scaly.

Clavicles perfect. Species 1. C. Fiber. The Castor Beaver. Jonst. Quadr. p. 147.

t. 68. Buff. viii. xxxii. Cuvier, Reg. Animal, vol. i. p. 190. Officinal. Castoreum1, Lond. Edin. Dub. Castor; Russian and Canadian.

Syn. Castoreum (F.), Kastoreunt, das Bibergeil (G.), Bevergeil (Dutch), Baevergel (Dan.), Bafvergall (Swed.), Stroy Bobrowy (Polish), Castoro (I.), Castoreo (S.) Ash batchegan (A.), Goond beyduster (Pers.), Beuer, Bever (old Scotch), Los lydan ( Gaelic), Afange ( Welch).

The beaver is an amphibious quadruped, found in the northern parts of Europe, Asia, and America2, inhabiting the wooded uninhabited banks of deep rivers and lakes , in which situations it is gregarious, and constructs its habitation with greater skill than any other animal except man. The hut, if it may be so named, serves for more than one family, and consists of two stories, the upper one for the animals, and the lower for the provisions. The body is thick, under three feet in length, and covered with short iron-brown and chesnut-coloured hair: the feet are five-toed, and the hind ones webbed: the eyes small, round, and so acutely sensible of light as to remain open only in dull weather; and the ears short, hairy, and so formed, that the meatus is closely shut, when the animal plunges and is beneath the water. The tail is gray, about half the length of the body, flat, horizontal, Dioscoridis. The ancients erroneously believed that the castor follicles were the testicles of the beaver.

2 It has been asserted that the beaver is found also in Africa; yet naturalists have not been able to find more than one species. It was formerly found in Wales, in the river Teivi. Giraldus Cambrensis mentions them in 1188. Sib-bald has the following sentence -"Boethius dicit fibrum seu castorem in Scotia repenri."-Prod. p. ii. 1. 3. p. 10.

scaly, with that part only of it which is next to the body covered with hairs. Between the anus and the external genitals are four follicles, of an oblong shape, smaller above and larger below; the two smaller are filled with a fatty substance, while the two larger contain each about two ounces of an oily, viscid, strong-smelling substance, enclosed in membranous cells, which is the officinal castor.

When the beaver is taken, the follicles are cut off entire, and dried, either by exposure to the sun or in smoke. The castor is at first nearly fluid, but gradually becomes solid and viscid, occasionally perfectly dry and pulverulent. The best comes from Russia; but of late years it has been very scarce, -and all that is now found in the shops is the produce of Canada. The cods of the Russian Castor are large, dry, roundish, heavy, and solid, appearing, when cut, of a reddish liver colour; those of the Canadian are smaller, hard, oblong, thin, and corrugated on the outside. The Canadian castor, when treated with ammonia, affords an orange-coloured product; the Russian a white. In each beaver there is a large and small bag, and the castor in the larger bag is always the best. The goodness of the castor is determined by its sensible qualities; that which is quite black is insipid, inodorous, oily, and unfit for use. Castor is said to be sometimes counterfeited by a mixture of some gummy and resinous substances, with a little real castor, artificially interspersed with membranes, and stuffed into the scrotum of the goat.1 The fraud is easily detected by comparing the smell and taste with those of real castor, and by the deficiency of the sebaceous follicles, which are always attached to the real cods.

Qualities.- The odour of castor is strong, heavy, and aromatic; the taste bitter, sub-acrid, and nauseous. It feels slightly unctuous, and is of a red-brown colour. Its odorous principle it dissipated by coction with water; but when it is simply infused in boiling water its sensible qualities are in a small degree imparted to the infusion, which has a yellow colour, and shows the presence of an alkali, by changing to green the vegetable blues. Alcohol and sulphuric ether dissolve the resinous part of the castor, which remains after the evaporation of the menstrua, and retains all the odour and taste of the drug. According to the analysis of Bouillon Lagrange, castor contains the carbonates of potassa, lime, and ammonia, iron, resin, a mucilaginous extractive matter, and a volatile oil. Canadian castor contains benzoic acid, both free and combined.1 Bonn, who examined Russian castor, found in it a volatile oil, adipocire, resin, and lime.2 M. Brandes found in it a peculiar principle which he termed castorin; which crystallizes in long, semitransparent prisms, with the smell of castor, and having a coppery taste; insoluble in cold water and cold alcohol, but soluble in boiling alcohol and in the volatile oils.

1 Duncan's New Edinburgh Dispensatory, 5th edit. p. 220.

Medical properties and uses,-Castor is antispasmodic, and emmenagogue. It was formerly given in combination with myrrh as a specific in quartans3; and is still prescribed, with seeming advantage, in low nervous fevers, hysteria, epilepsy, and spasmodic affections: and from the idea of its action being particularly determined to the uterine system, it is supposed to prove useful in amenorrhcea and chlorosis. It may be exhibited either in powder or in the form of tincture; but owing to the scarcity and the high price of good castor, it is seldom ordered; and the materia medica certainly contains many better antispasmodics.

The dose of powdered castor is grs. x. to Э j., given as a bolus.

Officinal preparation.- Tinctura Castorei, L. E. D.