1039 
out) further between bigeminusgroups and the halved rhythm of the 
ventricle. These variations of rhythms, which can occur spontaneously, 
1 could likewise bring about experimentally. A few examples may 
follow here. 
In Fig. 10 I apply at 1 during the 10,, systole an extra-stimu- 
lation to the basis of the ventricle at a moment at which the ven- 
tricle is still refractory. By current-loops the auricle is incited to 
an extra-contraction, after which an extra-pause follows. The next 
following systole of the ventricle has considerably increased after 
the prolonged pause, by which the ventricle is fastened in the halved 
rhythm. By means of a succeeding extra-stimulation at 2 at the end 
of the pause this halved rhythm of the ventricle is changed again 
into the normal one. At 3 I change this normal rhythm of the 
ventricle again into the halved one. 
In fig. 11 we see the representation of the curves of another 
poisoned heart. During the first 3 curves of the figure the heart 
pulsates in the normal rhythm of the ventricle. At 1 I apply an 
extra-stimulation to the point of the ventricle, which causes a little 
extra-systole. The postcompensatory systole is much enlarged. Then 
3 more of these enlarged systoles follow, but each of these enlarged 
systoles is followed by a very slight contraction of the ventricle 
which varies a little in size (indicated by the figures 2). We have 
here consequently the balved. rhythm of the ventricle with this 
reservation, that every systole of the ventricle is still followed by a 
slight contraction of the muscle of the ventricle. This rhythm of the 
ventricle passes spontaneously into the normal one. At-4 I modify 
this normal rhythm, in the same way as at 1, by an extra-stimula- 
tion into the halved rhythm of the ventricle (at the figures 2 again 
slight contractions of the ventricle occur). At 3 1 apply again at the 
end of the diastole an extra-stimulation to the point of the ventricle. 
A little extra-systole with a refractory stage of short duration is the 
result. The normal rhythm of the ventricle is restored by it. 
Fig. 12 represents curves of a frog’s heart after poisoning with 
digitalis. In the figure we see first 3 bigeminusgroups occasioned by 
the falling out of every 3"4 systole of the ventricle. These bigemi- 
nousgroups pass spontaneously into the normal rbythm of the ven- 
tricle. At 1 an extra-systole of the auricle not followed by a systole 
of the ventricle occurs after an extra-stimulation of the auricle. 
Under the influence of the prolonged pause the next following 
systole of the ventricle is now considerably enlarged, the consequence 
of this is, that now bigeminousgroups set in. By an extra-stimulation 
to the auricle in the pause between 2 groups at 2 this bigeminy is 
66* 
