The rhizome and rootlets of Leptandra virginica (Veronica virginica).

Characters. - Horizontal, from four to six inches (10 to 15 centimetres) long, and about a quarter of an inch (6 millimetres) thick, somewhat flattened, bent and branched, deep blackish-brown, with cup-shaped scars on the upper side, hard, of a woody fracture, with a thin, blackish bark, a hard, yellowish wood, and a large, purplish-brown, about six-rayed pith; rootlets thin, wrinkled, very fragile; inodorous; taste bitter and feebly acrid.

Dose. - Of the root, 20-60 gr. (1.5-4 gm.).

Composition. - It contains a resinous principle, leptandrin.

Action. - It is an irritant to the gastro-intestinal mucous membrane, and stimulates the secretion of bile (p. 403). It may be used as a cathartic in biliousness or constipation.