102 INORGANIC AGENTS 



Sodium perborate is a white^ granular, odorless salt containing not less 

 than 9 per cent, of available oxygen. It is soluble and when it goes into 

 solution it sets free hydrogen peroxide and sodium metaborate producing 

 an alkaline product. It is very useful on wounds, ulcers and raw sur- 

 faces on account of its being alkaline and permanent. It is used in 2 

 per cent, solution or as a dusting powder and, like HjOj, tends to stop 

 hemorrhage and is both antiseptic and deodorant. Zinc peroxide is a 

 yellowish-white, light, tasteless, odorless, insoluble powder, but liberates 

 oxygen in contact with living tissue. It is used as a dusting powder on 

 raw surfaces and gives up its oxygen slowly and possesses a slight alka- 

 line reaction when moist. 



\ 

 SECTION II. 



Alkaline Metals^Potassium, Sodium, Ammonium, Lithium. 



Potassium. 



Potassium is not used in medicine in the metallic state. Its com- 

 pounds may be considered in three groups; 1, Potassaj 2, the Carbonates 

 (acetate and citrate) ; 3, the Mineral Salts. 



Potassium compounds were formerly obtained from wood ashes by 

 lixiviation; from sea water by evaporation, and from argol, a substance 

 deposited in wine casks. Now they are obtained from potassium muriate, 

 mined in Stassfurt, Saxony, which is thought to result from the boiling 

 away of sea water in past ages. 



General Action of Potassium Salts. 



The action of salts on the body is determined not by the action of 

 the chemical compound or its molecule but by the action of the ions which 

 are dissociated when the salt goes into solution. Thus the action of potas- 

 sium on the body may be studied by observing the action of KCl since 

 the influence of the CI ion (anion) may be ignored as it induces no physio- 

 logical effect upon the organism. 



In lethal doses the action of all the potassium compounds is very 

 similar. 



Stomach and Intestines. — The potassium salts, with the exception of 

 the vegetable compounds, are irritants to the gastro-intestinal tract, if 

 ingested in concentrated form. 



Heart. — When injected into a vein, potassium has a direct, paralyz- 

 ing action on the heart muscle, and in lethal doses there is cardiac arrest 

 in diastole. Much the same action is, moreover, observed on all higher 

 forms of tissue. The functional activity of the nerves and muscles is 

 depressed and abolished, more especially that of the brain and cord, so 

 that paralysis of central origin occurs. 



Potassium has, however, no depressing influence upon the heart when 

 given by the mouth, as enormously greater amounts than are ever given 

 medicinally are daily consumed in the food. Bunge estimates from 60 

 to 100 grams may be thus daily ingested in food by man. This fact ex- 

 plodes the fallacy that sodium salts are less depressant to the heart than 



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