219 
on the Action of Poisons on the Animal System . 
-five minutes, from the beginning of the experiment, he was 
apparently dead ; but the heart was still felt through the ribs 
acting one hundred times in a minute. A tube was introduced 
into the trachea, and the lungs were inflated about thirty-six 
times in a minute ; but the pulse sunk notwithstanding, and 
at the end of seven minutes the circulation had entirely 
ceased. 
From these experiments I was led to conclude that the 
principal action of the muriate of barytes is on the brain ; 
but in the first the pulse was feeble and intermitting ; in the 
second, although the artificial respiration was made with the 
greatest care, the circulation could not be maintained more 
than a few minutes. These circumstances led me to suspect, 
that although this poison operates principally on the brain, it 
operates in some degree on the heart also. Further experi- 
ments confirmed this suspicion. In some of them the pulse 
soon became so feeble, that it could be scarcely felt ; and 
its intermissions were more frequent ; but in all cases the 
heart continued to act after respiration had ceased ; and the 
cessation of the functions of the brain was therefore always 
the immediate cause of death. When I employed artificial 
respiration, after death had apparently taken place, I seldom 
was able to prolong the heart's action beyond a few minutes. 
In one case only it was maintained for three quarters of an 
hour. I never by these means succeeded in restoring the ani- 
mal to life, although the experiments were made with the 
greatest care and in a warm temperature. In some instances, 
after the artificial respiration had been kept up for some 
time, there were signs of the functions of the brain being in 
some degree restored ; but the pulse notwithstanding conti- 
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