( 695 ) 
ventricle contraction, appears, at least partially, to be dependent 
on the lengthening of the refractory period, which has been demon- 
strated before by SrrauB with respect to the influence of antiarin on 
the heart. When white mice were subcutaneously injected, the last 
symptoms were heart-paralysis and irregularities; now ventricle and 
auricle beat in normal succession, now at the same time, sometimes 
in reversed succession; so besides the symptoms observed in the 
frogs we here find automatism of the ventricle, besides originating of 
the stimulus in the auriculo-ventricular zone. At last the heart stopped 
in diastole. 
Further experiments were made on rabbits; during the above- 
mentioned experiments also the blood-pressure was recorded. On 
administration of derrid a fall of the bloodpressure immediately ensued, 
which recovered itself however, often to its normal beight; after 
subsequent injections the bloodpressure fell more and more till at last 
heart-paralysis followed. 
The dose required for heart-paralysis is much larger than that for 
respiration-paralysis, even amounts to four times as much. Slowing 
of the pulse always manifests itself here as well. 
The above-mentioned symptoms were not influenced by cutting of 
the vagi, the sensitiveness of which appeared to remain unchanged. 
Further experiments were made on the isolated heart. For this 
purpose the rabbit was narcotised with urethane and ether ; thoracotomia 
was perforined and both parts of the thorax were turned aside; 
ventricle and auricle were registered. 
When derrid had caused stoppage of the breath, irregularities showed 
themselves in the function of the heart on further dosing ; sometimes 
ventricle and auricle contracted by themselves; dilatatio cordis was 
ever present; the end was always paralysis. 
To ascertain what was the cause of the fall in the bloodpressure, 
the following experiments were made: Of a rabbit in urethane- 
ethernarcosis that was afterwards curarised, the bloodpressure was 
registered as well as the oncometrical volume of the kidney or the 
intestine and that of a hind leg. It now appeared that after the injec- 
tion of the poison into the jugular vein the bloodpressure decreased 
simultaneously with the volumina of kidney, intestine and leg; if 
the bloodpressure increased, these volumina did the same. The volu- 
mina of the organs therefore followed the changes of the bloodpressure 
quite passively, so that the fall of the bloodpressure did not result 
from active dilatation. of the vessels but from weakening of the heart. 
So from all these experiments it appears that derrid acts on circu- 
lation, yet not so intensely as on respiration. The changes in the 
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