L146 
is an extra-systole of both ventricle and auricle at the same time 
(the irritation originated thus evidently in the connection-systems of 
these two partitions of the heart). The pauses between the first 5 
curves are equal in length. Then we obtain alternately longer pauses, 
whilst between these longer pauses again normal ones occur (normal 
at least for this row of extra-systoles). So bigeminus-groups develop 
themselves, the two curves of which consist of extra-systoles of 
ventricle and auricle at the same time. It is evident that here the 
connection-systems between the sinus venosis and the auricle are 
Fig. 10. 
Upper row: Extrasystoles of ventricle and auricle in frog’s heart poisoned with 
veratrine after blockading of the si-a connecting systems. The curves range 
themselves from the sixth curve in bigeminus-groups. 
2nd row: Cessation of the heart-blockade, the ventricle pulsates in the halved 
rhythm. 
3rd row: Increase of the u-r-interval of curve 1—4; after the falling out of 1 
ventricle-systole shortening of the w-v-interval, which is lengthened again already 
in the following curve. 
blockaded. It is difficult to explain the cause why the extra-systoles 
range themselves here in bigeminus-groups. In the 2"¢ row we see 
still 2 extra-systoles, after which suddenly the separate auricle- and 
ventricle-systoles appear again. The ventricle pulsates in the halved 
rhythm. The auricle-rhythm is much quicker than that of the extra- 
systoles. This is an affirmation of the well known fact that the 
peculiar rhythm for auricle and ventricle is much less frequent than 
the rhythm that originates in the sinus venosis (2"¢ Srannivs ligature). 
The lower row of curves shows again a lengthening a-v-interval, 
till the 5'® ventricle-systole falls out; for the next-following heart- 
