Characters. - Small, colourless or white rectangular plates, or a white granular powder, deliquescent on exposure to air, odourless, having a sweetish saline taste and a neutral reaction.

Solubility. - Soluble in 1 part of water and in 30 parts of alcohol at 15° C. (59° F.); in 0.12 parts of boiling water, and in 1 part of boiling alcohol.

Reactions. - When heated in a dry test-tube the salt loses water, and then evolves a spontaneously inflammable gas (phosphoretted hydrogen), burning with a bright yellow flame. A fragment of the salt imparts to a non-luminous flame an intense yellow colour, not appearing more than transiently red when observed through a blue glass. On triturating or heating the salt with an oxidising agent the mixture will explode.

Dose. - 1 to 10 grains (5 to 10 grs. B.P.).

Preparation.

u.s.p.

Syrupus Hypophosphitum.

Uses. - It is said to have a stimulating action upon the nervous system, and to increase digestion and nutrition. It is chiefly given in the earlier stages of phthisis (vide p. 717), and in anaemia and nervous debility.