THE 



INOEGANIC MATEEIA MEDICA. 

 GROUP I. 



THE ALKALIES AND ALKALINE EARTHS. 



OF the alkalies and alkaline earths, potassium, sodium, 

 ammonium, lithium, calcium, magnesium, and barium 

 are used in medicine. These, together with their many 

 salts, alone constitute a large proportion of the inor- 

 ganic materia medica. Whilst each of them is so 

 important as to require separate consideration, many 

 facts connected with their action and uses are common 

 to the whole group, and much that is said under 

 the head of Potassium, the first of the series, will not 

 require to be repeated under the others. 



POTASSIUM. K. 39. 



The salts and preparations of potassium are most 

 conveniently discussed in the following order : 



1. Potassae Carbonais. Carbonate of Potash, 

 K 2 C0 3 , with about 16 per cent, of water of crystallisation. 



Source. Obtained from wood ashes by lixiviation, evapo-L 

 ration, and crystallisation. 



Characters. A white crystalline, very deliquescent powder, 

 of caustic alkaline taste. 20 gr. neutralise 17 gr. of citric 

 acid, or 18 gr. of tartaric acid. 



Impurities. Sulphates and chlorides. 

 .lQ to 30 gr. 



