1080 
again after the lapse of not too long a time into the not halved one. 
I saw also repeatedly variations of rhythm occur spontaneously. 
When the poisoning-process increased these variations of rhythm 
resulted in the halved rhythm, which by further halvings applied to 
1 ventricle-systole caused 4, 8 or sometimes 5, 6, or 7 auricle-systoles. 
At the reaction of the poisoning during the halving period these 
variations of rhythm are accompanied with varying lengthening and 
shortening of the a-v-interval. The lengthening occurs during the 
quick rhythm, the shortening by restoration during the slowly 
halved rhythm. 
When the poisoning continues, no restoration takes place, but 
through lengthening of the a-v-interval and the refractory period 
further halving is the necessary result. 
2. The transmission of stimulation in the ventricle. 
We have seen that by poisoning with veratrine the transmission 
of stimulation between auricle and ventricle slackens. The mechano- 
grams do not tell us anything about the transmission of the stimula- 
tion in the ventricle-muscle itself. In order to obtain more information 
about this subject I reproduced the action-currents before and at 
fixed times after the poisoning. 
In Fig. 2 we have the suspension-curve and the electrogram of 
a not poisoned frog’s heart. Time in '/, sec. Electrodes auricle- 
ventrical. 
Whilst leaving for the rest all the circumstances the same, I 
make 12 minutes after the injection of 5 drops 1°/, acet. veratrine 
(vide Fig. 3) another reproduction. 
The R-top is raised and widened, it is somewhat split. 
The T-top has become positive, the line of connection between 
R and the T is lowered. The heartrhythm has slackened. The pauses 
between the mechanograms have lengthened, but those between the 
electrograms have shortened. The electrograms before the poisoning 
lasted till the beginning, after the poisoning till the end of the diastole ; 
the duration of the electrograms runs parallel with the duration of 
the refractory period. 
Both are indications of the metabolic processes of the heart-muscle. 
After the poisoning the beginning of the R-oscillation goes much 
more in advance of the suspension-curve than before the poisoning. 
The period of the latent irritation has consequently considerably 
lengthened after the poisoning. 
Directly after the halving of the ventricle-rhythm, 1 hour 20 min. 
after the injection I obtain the representation of Fig. 4. 
