(Potassium Hydroxide; Caustic Potash; Potassa. U. S. P., 1890.)

Origin. - Prepared by evaporating liquor potassae, fusing the residue, and pouring into clean cylindrical molds which have been previously warmed.

Description and Properties. - Dry, white, translucent pencils, or fused masses, hard and brittle, showing a crystalline fracture; odorless or having a faint odor of lye, and of a very acrid and caustic taste. Because of its active effect upon organic tissues it should be tasted and handled with exceeding care. Exposed to the air, it rapidly absorbs carbon dioxide and moisture, and deliquesces. Soluble in about 0.4 part of water and in 2 parts of alcohol. Potassa should be kept in well-stoppered bottles made of hard glass. Used externally.