On Electrical Stimulation of the Frog's Heart, 



481 



In G 1 water of melted ice had passed through the support for 

 two minutes. 



Gr 2 water had passed 5'. 

 Gr 3 „ „ 10'. 

 G 4 „ 20', 



Gr T Duration of contraction l"'4i . . Length of pause from 



stimulation . . 4' ''2 



G 2 35 33 . . 1 ''9 . . 5 '6 



G 3 „ „ .. 2"-2 .. „ „ 6"-0 



Or, „ „ •• 2"-4 .. „ „ 6"-2 



Gr 5 was obtained from a heart cooled for a considerable time, and 

 shows a remarkable prolongation of the systole and diastolic pause. 

 Gr 5 Duration of current 4" '4 . . Length of pause from 



stimulation. . 10" 



It will be seen in all these cases that there is a certain relation- 

 ship between the length of the contraction and of the pause. 



Ij to I 3 . Levers as in A. Stimulation of Yenous Sinus (maximal). 



