37 
Mr. Brodie’s Experiments, &c. 
observations of Mr. Cruikshank * and M. Bichat ,-f that the 
brain is not directly necessary to the action of the heart, and 
that when the functions of the brain are destroyed, the circu- 
lation ceases only in consequence of the suspension of respira- 
tion. This led me to conclude, that, if respiration was 
produced artificially, the heart would continue to contract 
for a still longer period of time after the removal of the 
brain. The truth of this conclusion was ascertained by the 
following experiment. 
Experiment 1. 
I divided the spinal marrow of a rabbit in the space between 
the occiput and atlas, and having made an opening into the 
trachea, fitted into it a tube of elastic gum, to which was con- 
nected a small pair of bellows, so constructed that the lungs 
might be inflated, and then allowed to empty themselves. By 
repeating this process once in fi ve seconds, the lungs being 
each time fully inflated with fresh atmospheric air, an artifi- 
cial respiration was kept up. I then secured the blood-vessels 
in the neck, and removed the head, by cutting through the soft 
parts above the ligature, and separating the occiput from the 
atlas. The heart continued to contract, apparently with as 
much strength and frequency as in a living animal. I exa- 
mined the blood in the different sets of vessels, and found it 
dark-coloured in the venae cavae 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. 
* Philosophical Transactions 1795. 
+ Recherches Physiologiques sur la Vie et la Mort. 
