1145 
when these groups had existed 45 minutes, extra-systoles intervened 
between the groups. It is well-known, that these occur by preference 
in greater pauses. 
Halving of the rhythm has not been attained with this heart; 
most likely it would have occurred, if the poisoning had made 
greater progress. So | often saw p-bigeminus as a transition from 
the normal rhythm into the halved one and in transitions of rhythms 
(vide Fig. 6). 
Here we see in the upper-row of curves (20 min. after the injection 
of 4 drops of 1°/, veratrine) bigeminus-groups pass into the normal 
rhythm; 5 minutes before the bieeminus-groups the rhythm was 
halved: in the next row (5 min. later) we have again bigeminus- 
groups, and 15 min. after this (Br row) the rhythm is: halved 
int os 
First row: Suspension-curves of the unpoisoned frog’s heart; 2nd 10 min. after 
the injection of 10 drops of 1/0 acel. veratrini; 3rd row: 5 min. later halving 
of the rhythm; 4th row: 10 min. after row 3, the systoles of the halved rhythm 
grow smaller: 5th row: 9 min. after row 4, bigeminus-groups. These groups 
develop „themselves because each 3rd and each 2nd systole of the normal rhythm 
are represented; in the latter part of this row every 3rd systole can twice be 
observed. The bigeminus groups form here a transition between the halved rhythm 
and the rhythm, of which every 3rd systole of the rhythm shows itself. 
