705 



extra-stimulus on the basis ventriculi converted into the 

 normal one, and the latter again into the halved ventricle-rhythm. 

 The halved ventricle-rhj'thm was here also obtained by poisoning 

 with antiarine. 



The tirst ventricle-systole of the figure belongs still to the halved 

 I'hythra. A short time after the end of the diastole the ventricle-basis 

 receives an extra-stimulus, through which the halved ventricle-rhythm 

 is converted into the normal twice as quick rhythm. 



When we compare now the ventricle-electrograms of these two 

 rhythms, we are immediately struck by the fact (hat the R-oscillations 

 during the normal ventricle-rhythm are widei- than those during 

 the halved rhythm. 



In the halved ventricle-rhythm the T-oscillations are negative but 

 very little, and the line of connection between the R and the T lies 

 just above the position of rest of the string. In the normal ventricle- 

 rhythm the T-oscillations are likewise negative but rather large, 

 and the line of connection between the R aud the T lies now below 

 the position of rest of the string. 



The basis ventriculi receives another stimulus at the 2'"^ rising 

 of the signal, which gives rise to a little abortive systole. After the 

 compensatory pause the ventricle is fixed again into the halved 

 rhythm through the post-compensafory systole. The ventiicle electro- 

 grams have likewise again obtained the same shape as in the 

 beginning of the figure. 



In Fig. 8 the ventricle pulsates in the beginning likewise in the 

 halved rhythm (after poisoning with antiarine). At i the ventricle- 

 basis receives an extra-stimulus, causing an extra-systole of the 

 ventricle. After this the halved ventricle-rhythm continues however. 

 When thereupon at 2 the exti-a-stimulus is repeated a little earlier 

 in the ventricle-period, the conversion into the normal ventricle- 

 rhythm succeeds, but after 3 systoles it changes again into the halved 

 one. During the halved rhythm again little abortive ventricle-systoles 

 occur, the triangular electrograms of which are indicated by an a. 

 During the halved ventricle-rhythm the T-,oscillation is positive, and 

 the line of connectioji between the R and the T is above the 

 position of rest of the string. At the qnicker normal ventricle-rhythm 

 the R-oscillations are considerably widened, the T is strongly 

 negative and the line of connection between the R and the T has 

 descended far below the position of rest of the string. 



We find these proportions not only with poisoned hearts, but not 

 poisoned frogs' hearts show the same phenomejia. Fig. 1 of one of 



