124. BISTORTA.—BISTORT. The rhizome of Poly'gonum bistor'ta Linné. Habitat: Europe, Northern Asia, and Northwestern United States, in moist places. An S-shaped rhizome (bent upon itself—bistorted), flattened, and transversely striate on upper side, and convex, with depressed rootscars, on lower side; color dark reddish-brown, internally lighter; fracture smoothish, showing a thick bark and a pith of about the same thickness as the bark. Contains tannin, 20 per cent., and starch, with red coloring matter. Tonic and astringent. Dose: 8 to 30 gr. (0.5 to 2 Gm.), in decoction.