Magnesium, Calcium, Potassium and Sodium. 85 



48 (304) 



The relative toxicity of the chlorides of magnesium, calcium, 

 potassium and sodium. 



By DON R. JOSEPH and S. J. MELTZER. 



\_From the Department of Physiology and Pharmacology of the 

 Rockefeller Institute for Medical Research^ 



Sodium, potassium, calcium and magnesium are normal con- 

 stituents of the animal body. However, when introduced intra- 

 venously in larger quantities they may have a poisonous effect. 

 Pharmacologists frequently speak of the effect as a salt action. 

 This means, at least according to the definition of some pharma- 

 cological writers, that the effect is due to osmotic changes. If 

 this were true, the toxicity of all four inorganic, basic elements 

 ought to be the same if introduced in the same molecular concen- 

 tration. Although, as far as we know, a direct comparative study 

 of the toxicity of these inorganic substances has never yet been 

 made, a glance at the various data in the literature suffices to show 

 that these substances differ greatly in their toxicity. As far as 

 we can gather, it is generally assumed that potassium is the most 

 poisonous ; calcium seems to be considered a good deal less poi- 

 sonous than potassium, but definitely more so than magnesium. 

 As to sodium, only recently Loeb and his pupils called attention 

 to its poisonous effect. 



In a series of experiments on dogs, we compared the toxicity 

 of these four inorganic elements in intravenous injections of their 

 chlorides. In every instance molecular solutions were employed. 

 The toxicity of each of these salts was tested on twelve animals. 

 The injections were made by four different methods, using three 

 dogs for each method, namely, by injections through the jugular 

 vein, through the femoral vein, through the splenic vein, and intra - 

 arterially, through the central end of the carotid artery. In the 

 latter case the solution was driven by high pressure through a 

 capillary tube. Except in the case of sodium chloride, the solu- 

 tions ran in uniformly one c.c. per minute. In order to be able 

 to finish an experiment in one day, the solutions of sodium chloride 

 had to be run in at the rate of two c.c. per minute. Each of the 

 solutions was permitted to run in until the animal died. 



