Contractions. - Mag-c. Mag.

Present name. - Magnesic Carbonate.

Light Carbonate of Magnesia.

The preparation used by homceopathists is a combination of Carbonate and Hydrate of Magnesia, having the following composition: (MgCo3)3,MgO,5H1O. It may be prepared as follows: -

Take of

Sulphate of Magnesia . . .

10 ounces;

Carbonate of Soda . . .

12 ounces;

Distilled Water ....

A sufficiency.

Dissolve the Sulphate of Magnesia and the Carbonate of Soda each in half a gallon of the water, mix the two solutions cold, and boil the mixture in a porcelain dish for fifteen minutes. Transfer the precipitate to a calico filter, and pour upon it repeatedly boiling distilled water until the washings cease to give a precipitate with Chloride of Barium. Lastly, dry by a heat not exceeding 212°.

Characters and Tests. - A very light powder, which, when examined under the microscope, is found to be partly amorphous with numerous slender prisms intermixed. Dissolves with effervescence in the diluted mineral acids, yielding solutions which, when first treated with Chloride of Ammonium, are not disturbed by the addition of an excess of solution of Ammonia, but yield a copious crystalline precipitate upon the addition of Phosphate of Soda. With excess of Hydrochloric Acid, it forms a clear solution in which Chloride of Barium causes no precipitate. Another portion of the solution supersaturated with Ammonia gives no precipitate with Oxalic Acid or Sulphuretted Hydrogen. 50 grains calcined at a red heat are reduced to 22.

Preparation. - Trituration.

Reference to Horn. Proving. - Chr. Kr., iv.

Proper forms for dispensing. - lx to 3, Trituration only. 4, dilute Tincture only. 5 and upwards, Tincture, Pilules, or Globules.