This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
The saccharated carbonate of manganese has no peculiar taste, the sulphate is styptic, metallic, and disagreeable. Small doses (5 to 10 gr.) of these salts are said to promote appetite and digestion, but larger quantities are apt to irritate, and cause vomiting and purging. The oxide, which is gritty on the tongue, is said to exert rather a sedative action on the gastric membrane.
The sulphate of manganese has been especially credited with the power of stimulating the secretion of bile since the observations of C. G. Gmelin, who found in animals poisoned by large doses, inflammation of the stomach, intestines, etc., and "so large an amount of bile poured out that the whole tract was colored like yellow wax." He reported a less degree of the same effect in man, and Mr. Ure also found that 60 to 120 gr. acted as a cholagogue purgative (Pereira). Dr. Goolden took various doses, from 1 up to 30 gr., before any vomiting occurred, but states that as a rule 10 to 20 gr. will cause some nausea and free purging with copious secretion of bile (Lancet, 1840, and i., 1878). Dr. Rutherford, however, failed to corroborate this experience, at least in animals, for after giving 60 gr. to a dog the biliary secretion was at once lessened and severe diarrhoea occurred. After death the mucous membrane of the small intestine was found pulpy, "as if the epithelium had been dissolved by caustic." In another dog a dose of 20 gr. equally caused lessening of bile, although benzoate of soda given afterward had power to restimu-late its secretion. Dr. Rutherford concludes that the drug is a powerful intestinal, but not an hepatic stimulant, acting very like sulphate of magnesia (v. p. 235). Nitrogenous excretion is increased by it. Poisonous doses induce acute fatty degeneration of the liver, like phosphorus.
Iron may be considered as allied in action to manganese within the limits of the preceding observations; the two substances are constantly associated in nature. Copper, silver, and zinc have allied effects on the nervous system. Goolden speaks of sulphate of manganese as substitutive for mercury as regards the action on the liver, but this is doubtful. He says also that it aids the action of sulphate of magnesia, and Rutherford has shown some analogy between these two salts.
Caustic alkalies and salts of lead, silver, and mercury are chemically (not therapeutically) incompatible with manganese. Tannic acid and vegetable astringents are not incompatible, as they are with iron.