74 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
The return of beat of the ventricle was usually abrupt, suddenly bursting out in 
almost its full vigour. The beat of the ventricle was also often arrested five seconds 
to ten seconds earlier than that of the auricle. 
III. 300 mgrms. CHClj per Litre Modified Ringer's Solution 
(CHCl, in '03 per cent, dilution) 
This strength of solution in every case practically extinguished the beat both 
of auricle and ventricle in thirty seconds from commencement of its administration 1 1 
the heart. But complete recovery both of ventricle and auricle was obtained in every 
case. The recovery was complete and rapid, even after continuous exhibition of the 
drug for eighteen minutes. Two types of recovery seemed distinguishable. With 
CHC1 3 solutions of -0001, or less, the beat recommences within about fifteen seconds 
from discontinuance of the administration. With the strength of solution now under 
consideration, namely, "OOOi CHC1 ? , in one form of recovery, about seventy seconds 
elapse before any sign of beat, and full recovery is not reached until from three 
minutes to four minutes have elapsed, and there is merely a gradual return to, and not 
beyond, the force and excursion obtaining prior to the exhibition of the CHC1 3 solution. 
A second type of recovery is characterized by much speedier return to a strength of beat 
in excess of that originally obtaining. In this type the returning beat becomes obvious 
fifteen seconds to twenty seconds after cessation of the administration of the CHCl p 
and fifteen seconds to twenty seconds later the heart beats far more vigorously than before 
the chloroformization, showing periods of distinct acceleration as well as augmentation 
of beat. Some excitation of the augmentor-accelerator nerves of the heart is suggested. 
Those nerves, as is shown later in this report, are not paralysed by considerable 
depths of CHC1 3 action. This type of recovery seems to occur especially frequently 
after prolonged administration of CHCl r 
IV. 150 mgrms. CHC1 5 per Litre Modified Ringer's Solution 
(C//C/, in "015 per cent, dilution) 
(Figs. 3, 4 and 5) 
With this strength of solution the amount of reduction of the activity of the 
auricle, as measured by reduction of the excursion of its recording lever, varied from 
83 per cent, (reduction) to complete abolition (temporary). The mean reduction of 
the auricle beat was 96*9 per cent, for twenty-one observations on six hearts. 
The mean reduction of the ventricle beat as similarly measured for the same 
six hearts was 97"6 per cent. 
The full effect of the CHClj solution was evident in about eighty seconds. 
Recovery was rapid and complete, both in auricle and in ventricle, in all cases. The 
beat began to improve within fifteen seconds of discontinuance of CHC1 3 perfusion, 
and recovery was complete about seventy-five seconds later. This held good even 
after prolonged perfusion, in one instance for more than ten minutes, in another for 
twenty minutes, continuous duration. (Fig. 5.) 
