266. Geranium.—Geranium, N.F.
DESCRIPTION OF DRUG.—Rough, knotty, cylindrical, horizontal, rhizome, 50 to 75 mm. (2 to 3 in.) long, and 10 mm. (2/5 in.) thick; longitudinally wrinkled, tuberculated, very hard, and sometimes beset with shriveled, brittle rootlets; externally dark brown; fracture short, reddish-gray, showing a thin bark, several small, yellowish wood-wedges forming a circle near the cambium line, and a large pith; medullary rays broad. The rootlets have a thick bark and a thin central column of fibrovascular tissue. Inodorous; taste astringent.
Powder.—Grayish-brown. Characteristic elements: Large aggregate crystals of calcium oxalate; ducts porous and reticulate; parenchyma with crystals and starch.
CONSTITUENTS.—Tannic (12 to 37 per cent.) and gallic acids, with resin, starch, gum, pectin, and a red coloring matter. Both alcohol and water extract its virtues.
ACTION AND USES.—A valuable and pleasant astringent. It has been claimed that the rhizome contains mucilaginous material which, acting as a demulcent, makes a decoction a much more desirable preparation than a simple solution of tannin. The fluidextract is said to be useful in buccal ulcer, etc. Dose: 15 to 30 gr. (1 to 2 Gm.).