54 MATER i A MEDIC A AND THERAPEUTICS. 



Impurities. Lime, iron, and general impurities. 

 Dose. 60 gr. to oz. 



Preparations. 



a. Enema Magnesia? Sulphatis. 1 oz., in 1 oz. of 

 Olive Oil, and 15 oz. of Mucilage of Starch; for one 

 enema. 



b. Mistura Sennas Composita. 1 oz. in 5 fl.oz. 

 See Senna. 



from Magnesice Sulphas are also made : 



c. Magnesias Carbonas. Carbonate of Magnesia 

 (heavy). (MgC0 3 ) 3 .Mg0.5H 2 0. 



Source. Made by mixing boiling solutions of Sul- 

 phate of Magnesia and Carbonate of Soda, evaporating, 

 purifying, and drying. 4MgS0 4 -f 4Na 2 C0 3 + H 2 = 

 3MgC0 3 ,Mg2HO + 4Na 2 S0 4 + C0 2 . 



Characters. A white granular powder, insoluble in 

 water. 



Impurities. Lime, sulphates, metals. 

 Jjose. 10 to 60 gr. 



Preparations. 



a. Liquor Magnesise Carbonatis. Solution of 

 Carbonate of Magnesia. "Fluid Magnesia." 

 MgC0 3 -f H 2 C0 3 or MgH 2 2C0 3 , in solution. 



Source. Made by passing an excess of Carbonic 

 Acid gas through a mixture of Carbonate of Magnesia 

 (freshly prepared) and water. 1 fl.oz. contains 13 

 gr. of carbonate. 



Characters. A clear fluid, sometimes effer- 

 vescing slightly. 



Dose. 1 to 2 fl.oz. 



ft. Trochisci Bismuthi. 2 gr. in each. 



from Magnesia Carbonas is made : 



Magnesia. Magnesia (heavy). Magnesia 

 Ponderosa. MgO. 



Source. Made by heating Carbonate of 

 Magnesia in a crucible to expel the carbonic 

 acid. 



Characters. A. white powder, compara- 

 tively insoluble in water (1 part in 5,412 cold 

 water, 1 in 36,000 hot water). 



Impurities. Those of the carbonates. 



Uose.W to 60 gr. 



d. Magnesise Carbonas Levis t Light Carbonate of 

 Magnesia. (MgC0 3 ) 3 .MgO.5H 2 O. 



