Stimulation of the Vagus Nerves. 



33 



between the beginning of rigor and the attainment of its maximum 

 is in the stimulated animals again shorter than in the controls. 



We shall not burden our present statements with figures or 

 other details. The essential point in our results is that with regard 

 to the cardiac rigor, stimulation of the inhibitory nerves had the 

 same effect as that obtained by stimulation of motor nerves upon 

 skeletal muscles, although the two kinds of nerves have opposite 

 functional characters. How is this puzzling result to be explained ? 

 We are inclined for the present to give our results the following 

 interpretation. It is known that anemia and venous stasis hasten 

 rigor. The onset of rigor in the lower extremities of a living 

 animal following compression of the abdominal aorta is a well- 

 known experiment. We believe that the frequent standstills and 

 slowing of the heart with its attendant anemia, venous stasis and 

 asphyxia of the tissues is the cause of the hastening of cardiac 

 rigor in the animals whose vagi were stimulated. In support of 

 this interpretation we may cite the fact that the rigor of the skeletal 

 muscles also sets in earlier in the animals whose vagi were stimu- 

 lated than in the controls, a fact for which the disturbance of the 

 circulation seems to be the only possible explanation. 



1 8 (274) 



The antagonistic action of calcium upon the inhibitory 

 effect of magnesium. 



By S. J. MELTZER and JOHN AUER. 



[From the Department of Physiology and Pharmacology of the 

 Rockefeller Institute for Medical Research^ 



Calcium and magnesium are chemically closely related ele- 

 ments. They are also close companions in the tissues of the 

 animal body. It is the prevailing view that the physiological 

 effect of both elements is similar in character. Many physiologists 

 are at present of the opinion that calcium as well as magnesium 

 exerts an inhibitory influence in the functions of the animal body. 

 Loeb published in 1 899 his observations of the inhibitory action of 

 calcium upon the twitchings of frog muscles brought on by solu- 

 tions of sodium chloride. It was then assumed by Loeb that all 



