Botanical Source.—Tormentil has a perennial, tough, woody rhizome, about the thickness and length of the upper joint of the forefinger, with numerous radicles. The stems are slender, weak, erect, often procumbent, branching at the summit, and 5 or 10 inches high. The leaves are almost sessile, and consist of 3 oblong, acute, deeply serrated, somewhat hairy leaflets; the stipules are smaller than the leaflets, and deeply cut. The flowers are small, bright-yellow, with the parts of the calyx and corolla in fours, and borne on slender, axillary, hairy stalks much longer than the leaves. Carpels corrugated when ripe (L.).
History and Description.—Tormentil, or septfoil, is a plant common to Europe. All parts of it are astringent, but the rhizome is the part usually employed. It has a very irregular external form, being sometimes cylindrical, at others, tuberculated. Externally, it is of a dark red-brown color; internally, flesh-red or brownish. Its taste is strongly astringent, and its odor faintly aromatic. Water takes up its astringent principle; the infusion forms a black-greenish precipitate of tannate of iron with ferric chloride, and a grayish, curdy one of tannate of gelatin with a solution of gelatin. In the Faroe and Orkney islands it is used in tanning leather; in Lapland it is used as a red dye. It is equally applicable in medicine with catechu, kino, and other foreign astringents.
Chemical Composition.—According to Reinhold (1867), tormentilla root contains tormentilla-tannic acid (C26H22O11; 24 to 30 per cent, Bowman, 1869), with quinovic (C24H33O4, Hlasiwetz) and some ellagic acid (C14H6O8). When the tannic acid is heated with diluted sulphuric acid, insoluble tormentilla-red, a phlobaphene, but no sugar, is formed. Rembold believes it identical with rhatany-red and hippocastanum-red. Fused with caustic potash, it forms phloroglucin and protocatechuic acid. Calcium oxalate is also a constituent of the root.
Action, Medical Uses, and Dosage.—Tormentil is astringent and tonic, and may be used in chronic diarrhoea and dysentery, passive hemorrhages, etc., in decoction; also as an astringent injection, and as a local application to flabby ulcers. Dose of the decoction, 1 or 2 fluid ounces; of the extract, 10 or 15 grains; of the powdered root, from 30 to 60 grains, 3 or 4 times a day. The extract maybe made by boiling 1 part of the coarsely-bruised root with 8 parts of water; straining; repeating the boiling with another equal quantity of water; mixing the two strained decoctions; and evaporating to the consistence of an extract. Alum or tannic acid may be added to this, as required.
Related Species.—Potentilla canadensis, Linné, Five-finger.—This is a perennial, villose-pubescent plant, frequently known by the name of Cinque-foil. It has a sarmentose, procumbent and ascending stem 2 to 18 inches in length. Leaves palmately 5-foliate; leaflets obovate, silky beneath, cut-dentate toward the apex, entire and attenuate toward the base. Stipules ovate, hairy, deeply 2 or 3-cleft, or entire. Flowers yellow, on long, axillary, solitary pedicels. Calyx segments lanceolate or linear; bracteoles of the calyx longer than the segments, nearly as long as the petals; petals obcordate, longer than the calyx. There are two varieties of this plant, the Potentilla canadensis, var. pumila, which is very small and delicate, flowering in April and May, growing in dry, sandy soils, and the stem rising about 3 or 4 inches. The other is the Potentilla canadensis, var. simplex, which is less hirsute with a simple stem, erect or ascending at base, and oval-cuneiform leaflets. It grows in richer soils to 12 and 16 inches high, and flowers from June to August (W.—G.). Five-finger is common to the United States, growing by roadsides, on meadow banks and waste grounds, and flowering from April to October. It is the Potentilla sarmentosa of some botanists. The root is the part used. It has a bitterish, styptic taste, and yields its virtues to water. This plant is a tonic and astringent. A decoction has been found useful in fevers, bowel complaints, night-sweats, menorrhagia, and other hemorrhages; also, it is an excellent local application in form of gargle, for spongy, bleeding gums, and ulcerated mouth and throat. The European herb, Potentilla reptans, possesses similar properties.
The following species contain a bitter body, mucilage, tannin, etc.: Potentilla reptans, Linné, Creeping cinque-foil; P. fruticosa, Linné, Shrubby cinque-foil; P. palustris, Scopoli, Marsh cinque-foil; P. anserina, Linné, Silverweed, Goose-grass; and P. argentea, Linné, Silvery cinque-foil.
King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.