When looking again at the ventricle-curves of fig. 5 of the pre- 
vious publication and of figs. 1, 2, and 3 of the present one we can 
state what follows: 
As soon as the normal ventricular rhythm is changed into the 
halved rhythm the magnitude and the duration of the ventricular 
systole increases. This increment then proceeds from systole to 
systole, so that the 10" systole of the halved-rhythm is much greater 
than the 5, which again in its turn is greater than the first. This 
increment of the magnitude of the ventricular systole is brought 
about by an increase of the maximum diastole and at the same time 
by an increase of the maximum systole. It will be seen, then, that 
the ventricular muscle recovers itself during the halved-rbythm and 
that this recovery proceeds under the influence of an increase of 
long ventricular pauses. The reverse will be observed after the 
change of the halved-rhythm into the normal. 
The ventricle is then in a good condition owing to the preceding 
halved-rhythm. Directly after the change into the normal rhythm, 
the magnitude of the ventricular systoles has decreased. But under 
the influence of the frequent recurrence of short ventricular pauses 
the magnitude of the ventricular systoles lessens more and more. 
This lessening regards the maximum diastole as well as the maximum 
systole. An intermediate form between the normal ventricular rhythm 
and the halved-rhythm is the ventricle-alternant. 
We can change the normal ventricular rhythm into the alternant 
and this again into the halved-rhythm, as illustrated in the following 
figures, derived from the same frog’s heart. The curves of figs. 4 
and 5 were taken after the bleeding. The ventricle was then pul- 
sating in the normal rhythm; at the first deflection of the signal 
the auricles received an induction shock resulting in an extrasystole 
of these chambers, which was followed by a small systole of the 
ventricle. At the second deflection of the signal again an auricular 
extrasystole was evoked in the beginning of the postcompensatory 
systole. Hereafter the excitation reaches the ventricle during the 
refractory stage, so that an extrapause of the ventricle ensued. Then 
the first ventricular systole is very much enlarged. This enlarged 
ventricular systole introduces an alternation of the ventricle. (Similarly 
in our previous experiments the halved-rhythm was brought about 
by an enlarged systole). After some time this alternation changes 
spontaneously into the normal ventricular rhythm with systoles of 
the same magnitude. 
At the third deflection of the signal again an extrasystole of the 
auricles is evoked, followed by a small ventricular systole. After the 
