413 



The positive T-oscillntion of the normal systoles during an extra- 

 systole can even produce a negative T, if at an early epoch of the 

 ventricle-period the ventricle is excited to an extra-contraction, and a 

 decreased positive T, if at a later epoch of the ventricle period the 

 ventricle is excited to an extra-contraction. 



A few examples may explain the above more accurately.') In the 

 figures 6 and 7 extra-stimnla were applied to the ventricle-basis at 

 the upward oscillations of the signal. In F'ig. 6 at 1 an extra- 

 stimulus is applied to the ventricle-basis immediately after the com- 

 pletion of the preceding T-oscillation. The T-oscillation of the extra- 

 systole which is positive at the normal ventricle-systole, becomes 

 now decidedly negative. At 2 a following extra-stimulus hits the 

 ventricle-basis at a much later epoch ; consequently the negative 

 T-oscillation is now much smaller. Here I already fix the attention 

 to the fact that the enlargement of the positive T-oscillation is so 

 much the more important during the postcompensatory -systole, in 

 proportion as the preceding extra-systole has been brought about at 

 an earlier epoch of the ventricle-period. 



In fig. 7 an extra-stimulus hits the ventricle-basis at 1 soon after 

 the completion of the preceding T-oscillation. This causes a great 

 negative T in the electrogram of the ventricle-extra-systole. At 3 the 

 extra-stimulus hits the ventricle at a later epoch, this makes the 

 T-oscillation smaller, at 2 the extra-stimulus comes still later, an 

 extremely little negative T-oscillation is the consequence. 



It is beautifully brought out here, that the enlargement of the 

 positive T-oscillations of the postcompensatory systoles is so much 

 the more important, in proportion as the extra-stimulus has hit the 

 ventricle-basis at an earlier epoch of the ventricle-period. 



The extra-stimulus was applied to the auricle in the figures 8 and 

 9, which proceed from the same frog's heart. At about the same 

 epoch of the ventricle-period the ventricle-systoles set in that are 

 brought about after auricle-extra-systoles by the conducted "Erregung" 

 after the extra-stimula applied at 1 and 4. The T is negative and 

 of the same dimension at both the ventricle-systoles brought about 

 in this way. The ventricle-systole sets in at a much later epoch of 

 the ventricle-periods after the extra-stimulus applied to the auricle 

 at 2. The T-oscillation remains now positive, though distinctly reduced. 

 , At 3 an extra-systole of the ventricle is brought about through 

 current-loops directly by the stimulus. 



1) In the following figures extra-stimula were only applied at the upward oscil- 

 lation of the signal. 



