Characters. - A white, semi-crystalline, or amorphous powder, efflorescent on exposure to air, odourless, or having a faint odour of benzoin, of a sweetly astringent taste, free from bitterness, and having a neutral reaction.

Tests. - When heated the salt melts, emits vapours having the odour of benzoic acid, then chars, and finally leaves a blackened residue of an alkaline reaction and exhibiting the reactions of sodium (p. 617). On mixing an aqueous solution of the salt with a dilute solution of ferric sulphate a flesh-coloured precipitate is produced.

Dose. - 10 to 20 grains.

Uses. - It has been strongly recommended as a remedy in phthisis, and has also been used in puerperal fever and to eliminate uric acid in gout.

Sodii Iodidum. - Vide p. 563. Sodii Bromidum. - Vide p. 555.