Origin. - It should contain not less than 90 per cent. of pure sodium nitrite. Obtained by heating sodium nitrate with lead, the oxygen from the nitrate being abstracted by the lead oxide formed.

Description and Properties. - White, opaque, fused masses, usually in the form of pencils, or colorless, transparent, hexagonal crystals; odorless, and of a mild, saline taste. When exposed to the air the salt deliquesces and is gradually oxidized to sodium nitrate. Soluble in about 1.5 parts of water; slightly soluble in alcohol. It should be kept in well-stoppered bottles.

Dose. - 2-5 grains (0.12-0.3 Gm.).