The bark of Salix alba, and of other species of Salix.

Characters. - In fragments or quills, from one-twenty-fifth to one-twelfth of an inch (1 to 2 millimetres) thick, smooth; outer surface somewhat glossy, brownish or yellowish, more or less finely warty; under the corky layer, green; inner surface brownish-white, smooth, the liber separating in thin layers; inodorous; bitter and astringent.

Composition. - It contains tannin and salicin. Use. - The infusion may be used as a bitter tonic.