On the Influence of the Brainon the Action of the Heart. 445 
the head, by cutting through the soft parts above the liga- 
ture, and separating the occiput from the atlas. The heart 
continued to contract, apparently with as much strength 
and frequency as ina living animal. [examined the blood 
in the different sets of vessels, and found it dark-coloured 
in the venz cave and pulmonary artery, and of the usual 
florid red colour in the pulmonary veins and aorta. At the © 
end of twenty-five minutes from the time of the spinal 
marrow being divided, the action of the heart became fainter, 
and the experiment was put an end to. 
With a view to promote the inquiry instituted by the 
Society for promoting the knowledge of animal chemistry 
respecting the influence of the nerves on the secretions*, [ 
endeavoured to ascertain whether they continued after the 
influence of the brain was removed. In the commence- 
ment of the experiment [ emptied the bladder of its contents 
by pressure ; at the end of the experiment the bladder con’ 
tinued empty. 
This experiment led me to conclude, that the action of 
the heart might be made to continue. after the brain was 
removed, by means of artificial respigation, but that under 
these circumstances the secretion of urine did not take 
place. It appeared, however, desirable to repeat the experi- 
ment on a larger and Jess delicate animal, and that, in doing 
so, it would be right. to ascertain whether, under these cir- 
cumstances, the animal heat was kept up to the natural 
standard. + 
Experiment 2.—I repeated the experiment on a iniddle- 
sized dog. The temperature of the room was 63° of Fah- 
renheit’s thermometer. By having previously secured the 
carotid and vertebral arteries, 1 was enabled to remove the 
head with little or no hemorrhage. ‘The artificial respira- 
tions were made about twenty-four times ina minute. The 
heart acted with regularity and strength. _ 
At the end of 30 ainutes from the time of the spinal 
marrow being divided, the heart was felt through the ribs 
contracting 76 times in a minute. 
At 35 minutes the pulse had risen to 84 in a minute. | 
At one hour and 30 minutes the pulse had risen to $8 in 
a minute. 
At the end of two hours it had fallen to 70,.and at the 
end of two hours and a half to 35 in a minute, and the arti- 
ficial respiration was no longer continued. 
* Philosophical Transactions for 1809. 
By 
