452 Influence of the Brainon the Action of the Heart. 
spiration, cooled more rapidly on the whole than the rabbit 
whose lungs were inflated in the same manner after the 
circulation had ceased. This is what might be expected if no 
heat was produced by the chemical action of the air on the 
blood; since in the last case the cold air was always applied 
to the same surface, but in the former it was applied always 
to fresh portions of blood, by which its cooling powers were 
communicated to the more distant parts of the body. 
Tn the course of the experiments which I have related, [ 
‘was much indebted to several members of the Society for 
promoting the Knowledge of Animal Chemistry, for many 
important suggestions which have assisted me in prosecuting 
the inquiry. Mr. Home, at my request, was present at the 
seventh experiment. Dr. E. N. Bancroft was present at, 
and assisted me in, the second experiment ; and Mr. Wm. 
Brande lent me his assistance in the greater part of those 
which were made. I have been further assisted in making 
the experiments by Mr. Broughton, surgeon of the Dorset- - 
shire regiment of militia, and Mr. Richard Rawlins and 
Mr. Robert Gatcombe, students in surgery. 
F have selected the above from a great number of similar 
experiments, which it would be needless to detail. It is 
sufficient to state, that the general results were always the 
same; and that whether the pulse was frequent or slow, full 
or small, or whether the respirations were frequent or other- 
wise, there was no perceptible difference in the cooling of 
the animal. 
From the whole we may deduce the following conclu- — 
sions: 
1. The influence of the brain is not directly necessary to 
the action of the heart. 
2. When the brain is injured or removed, the action of 
the heart ceases, only because respiration is under its in- 
fluence; and if under these circumstances respiration is arti- 
ficially produced, the circulation will still continue. 
3. When the influence of the brain is cut off, the secre- 
tion of urine appears to cease, and no heat is generated ; not- 
withstanding the functions of respiration and _ the circula- 
tion of the blood continue to be performed, and the usual 
changes in the appearance of the blood are produced in the 
longs. . 
4. When the air respired is colder than the natural tem- 
perature of the animal, the effect of respiration is not fo 
generate, but to diminish animal heat. 
LXXV. Fatal 
