PART li. Materia Medica. — Castoreum.

217

Ion Lagrange, the residue of the watery infusion evaporated todryness, and burnt, yields potass, sulphate of potass, carbonateof lime, magnesia, and silica.

Medical properties and uses. — Senna is purgative, generallyoperating under four fours after it is taken ; and is well adaptedfor all cases in which the bowels require to be certainly, yetmoderately evacuated. In many habits it is apt to occasiongriping, and therefore requires the addition of some aromatic,as carraway or cardamom seeds, or ginger, and its operationto be assisted by drinking plentifully of weak broths or gruel.The griping seems to be occasioned by the resinous matter, asthe infusion made with cold water does not gripe, although itpurges. Senna may be given in substance powdered ; but themore usual form is that of infusion. Decoction is a bad form,as the activity of the medicine is much impaired by the boil-ing : owing, according to Gren, to the total dissipation of thenauseous and volatile principles; but, in our opinion, to theoxidizement of the extractive, which also accounts for thesevere gripings induced by the decoction. The dose of the pow-der of the leaves is from £)j. to 3J.; but it is seldom given alone.

Officinal preparations. Corifectio Senna;, L. E. D. ExtractumCassia Senna, E. Inficsum Senna;, L.D. Iiifusum l^amarindi cumSenna, E. D. Pulvis Senna; conipositus, L. Tinctura Senna;,L. E. D. Tinct. Senna; composita, L. Syrupus Senna:, D.

CASTOR. Syst. Nat. Gmelin. 12*.CI. 1. Ord. 4. Mammalia, Glires.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, scaly. Clavicles perfect.Species 1. C. Fiber. The Castor Beaver. Jonst. Quadr. p. 147. t. 68.Officinal. Castoreum 1 , Lond. Edin. Castoreum Rossicum ct

Canadense, Dub. Castor; Russian and Canadian.

Si/n. Castoreum (JV.), Kastoreunt (<?.)> Castoro (7.), Castoreo (&), Ash-butchegan (A.), Goona beyduster (Pen.).

The beaver is an amphibious quadruped, found in the north-ern parts of Europe, Asia, and America, inhabiting the woodedbanks of uninhabited rivers and lakes; in which situations it isgregarious, and constructs its habitation with greater skill thanany other animal except man. The body is thick, under threefeet in length, and covered with short iron-brown and chesnut-coloured hair: the feet are five-toed and webbed; the eyessmall, and the ears short and hairy. The tail is about half thelength of the body, flat, horizontal, scaly, with that part onlyof it that is next to the body covered with hairs. Between theanus and the external genitals are four follicles, of an oblongshape, smaller above and larger below; the two upper are filled

i Kctpos Dioscoridis. The ancients erroneously believed that the castor follicles

were the testicles of the beaver.