34 



Scientific Proceedings (26). 



the members of the group of alkali earths possess inhibitory prop- 

 erties including at first even barium. In the numerous subse- 

 quent papers by Loeb and his pupils the discussion turned, how- 

 ever, essentially around the inhibitory effect of calcium. Outside 

 of the effect of calcium upon the heart, with reference to which 

 Howell and his followers insist, contrary to the teachings of Loeb 

 and his school, that calcium is an exciting and not an inhibiting 

 agent, the opinion is now widely accepted that calcium is an inhib- 

 iting factor in the animal organism. It found its way also into 

 pathology. For instance, a number of German and Italian writers 

 hold the view that tetany of children is due to a diminution of the 

 calcium content of the brain. 



As to magnesium we have within the last few years published 

 several studies in support of the hypothesis that magnesium salts 

 favor inhibitory processes. The first fact which gave rise to that 

 hypothesis was demonstrated in 1899 to the American Physio- 

 logical Society when an intracerebral injection of a few drops of a 

 solution of magnesium sulphate caused a state of paralysis in a 

 rabbit while the injection of other solutions brought on convulsions. 



In a series of recent studies which we have carried out upon 

 the relations of the effects of calcium to magnesium, many remark- 

 able facts came to light, all of which demonstrate unmistakably 

 that calcium is the most available agent to neutralize the inhibitory 

 effect of magnesium. We shall not enter here upon details ; we 

 wish to show only the following striking and instructive experiment. 



By subcutaneous injections of a magnesium salt rabbits are 

 brought to a profound state of anesthesia and paralysis. The 

 slow and shallow respirations indicate the approaching danger. 

 Now 6 or 8 c.c. mj6 or w/8 solution of a calcium salt is given 

 through the ear vein. Within a few seconds the respiration be- 

 comes quicker and deeper and within one minute the animal turns 

 over, sits up and appears normal. 



Here calcium not only did not add an inhibitory effect but 

 completely neutralized the profound inhibitory effect of magnesium. 

 The companionship of calcium and magnesium within the body 

 means, at least in many instances, not a concerted action of similar 

 effects but rather a resultant effect of antagonistic actions. 



We may add that the experiment calls to mind similar relations 



