534 
ventricle already in the middle of the diastole, i.e. directly after 
the conclusion of the refractory stage. Instead of a premature ven- 
tricular systole, an irregular fibrillation of this chamber ensues, 
which is followed by a short post-undulatory pause. During this 
PRIN PRON ON, ANBI SD ON 
fe Rg I Ef TEE LILO Dn 
Rig. 0. 
fibrillation the auricles maintain their regular pulsation: after the 
extrasystole of the auricles followed the ordinary compensatory pause 
and subsequently the auricles resumed their regular beat *). 
At 2 the auricles are again stimulated at the beginning of the 
excitable period. After this extrasystole of the auricles the ventricle 
readily resumes fibrillation after the conclusion of the a—v-interval. 
In this experiment the relations are much more intricate than in 
the experiments of the first paper, in which the ventricle was stimu- 
lated directly after the conclusion of the refractory stage, after which 
ventricular fibrillation ensued. After some trials I readily found this 
point and fibrillation could easily be excited. In the experiments we 
are describing now, this is not done so easily, which is readily un- 
derstood. 
First we have to fix the moment, when the refractory stage of 
the auricles terminates. But, this done, the success of the experiment 
depends on two more factors, viz: 
1 on the rate at which the excitation proceeds from the stimu- 
lated spot to the ventricle. 
1) The auricular curves have diminished during the ventricular fibrillation. This 
is on account of the altered mechanic relations of the registration consequent on 
the fibrillations of the ventricle. 
