699 



was extended on a cork-plate, and tlierenpon the heart was laid 

 bare in the usual way and suspended at the point. The oscillations 

 of the lever were photographed on the sensitive plate beside the 

 electrograms that were obtained after placing one unpolisarable 

 electrode on the heart point and one on the auricle. The time was 

 likewise indicated in all photograms in ^!^ second. The experiments 

 of the second and the third series were arranged in the same way, 

 but for these a stimulator was moreover placed against one of the 

 parts of the heart, and the moment at which the stimulus was 

 applied, was indicated on the sensitive plate by a signal that was 

 linked in the primary current-circuit of the induction-apparatus ^). 



In this series of ' photograms as well as in the two following ones 

 we shall trace in the tirst place the u^idth (duration) of the R-oscil- 

 lation, then the extent and the direction of the T-oscillation. We 

 call a T positive, when its direction is equal to that of the R-oscil- 

 lation, and negative when it is opposite to the lalter. Thereupon 

 we consider the line of connection between the R- and the T- 

 oscillation. When this line of connection is removed in the direct- 

 ion of the R-oscillation, it rises, it lowers, when it is removed in 

 a direction opposite to that of the R-oscillation. In this communi- 

 cation I shall consequently explain more accurately of the ()lioto- 

 grams represented only these 3 parts of the ventricle-electrograms. 



In order to avoid occupying too much room for the figures, 1 

 shall restrict myself to reproduce five photograms, one taken before 

 and four after the poisoniug with digitalis dialysate (Golaz). 



In F'ig. 1 the suspension-curves of a frog's heart are reproduced before 

 the poisoning and likewise the electi-ograms (deduction auricle-point). 

 The T-oscillation is positive, the line of connection between the R- and 

 the T-oscillation is above the line indicating the position of rest of 

 the string. Then I inject under the skin of the thigh 12 drops of 

 digitalis dialysatum. Another photogram is taken under equal condi- 

 tions fifteen minutes after the injection (Fig. 2). If we compare the 

 width of the R-oscillation of this photogram with that in Fig. 1, 

 we see that it has considerably increased. This teaches us that 

 the velocity of impulse-transmission through the ventricle has 

 decreased. The T-oscillation is still positive, but has become very 

 little and the line of connection between the R-oscillation and the 

 T-oscillation coincides now almost with the position of i-est of the 

 string. 



1) When the primary current-circuit was closed the signal moved downward, 

 when opened upward. The closing induction shocks were blended off, the opening 

 induction shocks directed towards the frog's heart. 



