It is a solution of carbonate of magnesium in water containing carbonic acid. It contains about 13 1/2 grains in the fluid ounce. It is a pleasant laxative for children; and laxative and antacid for women, especially useful during pregnancy.

B.P. and U.S.P. Liquor Magnesii Citratis. Solution of Citrate of Magnesium. - Dissolve citric acid, 200 grains, in 2 ounces of water, add carbonate of magnesium 100 grains, and stir until it is dissolved. Filter the solution into a strong half-pint bottle, add syrup of lemons 1/2 fl. oz. and enough water nearly to fill the bottle; then introduce bicarbonate of potassium in crystals 40 grains, and immediately close the bottle with a cork, which should be secured with string or wire. Afterwards shake the bottle until the bicarbonate of potassium has dissolved.

U.S.P. Mistura Magnesii et Asafoetidae (Dewees' Carminative). - Carbonate of magnesium 5, tincture of asafoetida 7, tincture of opium 1, sugar 10, distilled water up to 100. Dose. - 1/2 fl. oz. in hysterical flatulence.

Magnesia Levis, B.P.; Magnesia, U.S.P. Magnesia. Light Magnesia, MgO; 40.

Preparation.

U.S.P

Trochisci Magnesiae (3 grs. in each).

Magnesia Ponderosa, B. and U.S.P. Heavy Magnesia.

Characters Both are white powders differing from each other only in their weight, which is 3 1/2 to 1.

Solubility. - They are insoluble in water, but dissolve in acids without effervescence.

Reactions. - The solution in acids exhibits the reactions of magnesium.

Dose. - 10 to 60 grains of either heavy or light. Action and Uses. - Like those of the carbonate.

Officinal Preparation. Pulvis Rhei Compositus, 2 parts of heavy magnesia in 3.