334 : 
systole at 3 the rate of the conduction of excitation wave is not nearly so 
much diminished as with the first systole of the “gehäufte” ventri- 
cular systoles. Besides, the duration of the electrogram of the extra- 
systole at 3 is longer than that of the first electrograms of the 
“gehäufte”” extra-systoles. The quicker conduction as well as the 
longer duration of the ventricle-electrogram, i.e. the longer duration 
of the refractory stage, contribute to the fact that after the stimulus 
at 3 only one extrasystole reveals itself. After the quicker conduc- 
tion the excitation wave is checked by the longer refractory stage. 
We see then that the same rule holds for the origin of ‘““gehaufte” extra- 
systoles and for that of ventricular fibrillation. When the stimulus 
meets the ventricle directly after the close of the refractory stage, 
the “gehaufte” extra-systoles can come forth. But when in a frog’s 
heart that exhibits “gehaufte”’ systoles after being given an electric 
stimulus directly after the close of the refractory stage, the stimulus 
is applied at a later time of the ventricle period at the same spot 
and with the same force, one single extrasystole will appear. 
It appears therefore that the ‘“gehäufte’” extrasystoles originate 
only when the metabolic condition of the ventricle is bad, and con- 
sequently the excitation wave is conducted slowly through the ventricle. 
At the moment when the metabolic condition of the ventricle is bad, 
a stimulus will also evolve a brief extrasystole with a brief  refrac- 
tory stage. The appearance of the “gehäufte” extrasystoles, there- 
fore, is aided as well by the slow conduction of excitation as by 
the short duration of the refractory stage. Then after the first 
course through the ventricle which is of long duration, the excitation 
wave can go round once more, because the starting point has become 
excitable again at that moment. This may be repeated several times. 
The conditions for the origin of the “gehaufte’ extra-systoles are 
therefore the same as for the origin of ventricular fibrillation. The 
mechanism of the processes at work in the ventricular muscle during 
fibrillation and the “gehéufte’ extrasystoles, displays only differences 
in degree. In the case of both deviations from the normal rhythm 
the conduction of excitation wave has largely slackened and the duration 
of the refractory stage has decreased with its appearance. In the case 
of delirium cordis the excitation wave passes through the ventricle so 
slowly that every time different muscular areas of the ventricle are 
made to contract, so that the excitation wave proceeds through the 
ventricle slowly and by jerks. This leads to fractionated ventricular 
systoles, which are linked together for the time of the delirium. During 
the “gehéufte’’ extrasystoles, however, the refractory stage is. also 
shortened at the moment of its origin, but now the excitation spreads 
