Manganesii Oxidum Nigrum, B.P.; Mangani Oxidum Nigrum, U.S.P. Black Oxide of Manganese. - Native crude peroxide of manganese containing at least 66 of the pure oxide. Mn02; 86, U.S.P.

Characters. - A heavy black powder.

Solubility and Reactions. - Dissolves almost entirely in hydrochloric acid with evolution of chlorine, and gives off oxygen when heated to redness.

Uses. - Used for producing chlorine, and for making oxygen. It has been used instead of bismuth in pyrosis and irritable conditions of the stomach, with pain after eating; and instead of iron in debilitating diseases, anaemia, syphilis, scurvy, and in skin-diseases.

U.S.P. Mangani Sulphas. Sulphate of Manganese.-MnSO4.4H2O; 222

Characters. - Colourless or pale rose-coloured, transparent right rhombic prisms, odourless, having a slightly bitter and astringent taste, and a faintly acid reaction.

Solubility. - Soluble in water.

Reactions. - The aqueous solution of the salt yields, with sulphide of ammonium, a flesh-coloured precipitate completely soluble in moderately diluted acetic acid (absence of zinc); with test-solution of ferro-cyanide of potassium it affords a reddish-white precipitate, and a brown one with test-solution of ferricyanide of potassium.

Action of Manganese Salts. - When injected into the blood, or subcutaneously, manganese salts paralyse voluntary movement and reflex action, and stop the heart in diastole. The paralysis of reflex action is due to destruction of the transverse conduction of the spinal cord (p. 161), longitudinal conduction remaining intact until death (Robert). Proto-sulphate produces purging in doses of 1 to 2 drms., and, in consequence of Gmelin's experiments, has been thought to increase the secretion of bile.

Uses. - Has been used in place of iron in anaemia, but without good results. Possibly it may be serviceable in amenor-rhcea.

Potassii Permanganas, B.P. and U.S.P. - Vide p. 614.