The root of Apocynum cannabinum.

Characters. - Long, cylindrical, somewhat branched, one-fourth to one-third of an inch (6 to 8 millimetres) thick, pale brown, longitudinally wrinkled and transversely fissured; brittle; fracture short, white; the bark rather thick; the wood porous, spongy, with delicate, medullary rays and a thin pith; inodorous; taste bitter, disagreeable.

Composition. - It contains an amorphous substance - apo-cynin - easily soluble in alcohol, but insoluble in water, and a glucoside - apocynein - easily soluble in water.

Dose. - 15-30 gr. (1-1.95 gm.) of powdered root. A decoction is more convenient. It is made by boiling 1/2 oz. in 1 1/2 pint of water to 1 pint. Of this 1-2 fl. oz. (30-60 c.c.) may be given twice or thrice a day.

Action. - In small doses it is laxative, in large doses emetic and cathartic. Apocynin and apocynein act on the heart as cardiac tonics like digitalis, and are also diuretic.

Use. - It is chiefly used in dropsy.