4 6 Mr. Brodie’s Experiments on the 
was communicated to all parts of the body, in consequence of 
the continuance of respiration. 
It was suggested that some animal heat might have been 
generated, though so small in quantity as not to counter- 
balance the cooling powers of the air thrown into the lungs. 
It is difficult or impossible, to ascertain with perfect accuracy, 
what effect cold air thrown into the lungs would have on the 
temperature of an animal under the circumstances of the last 
experiment, independently of any chemical action on the 
blood : since, if no chemical changes were produced, the cir- 
culation could not be maintained, and if the circulation ceased, 
the cooling properties of the air must be more confined to the 
thorax, and not communicated in an equal degree to the more 
distant parts. The following experiment, however, was in- 
stituted, as likely to afford a nearer approximation to the 
truth, than any other that could be devised. 
Experiment 8. 
I procured two rabbits of the same size and colour : the 
temperature of the room was 64°. I killed one of them by 
dividing the spinal marrow, and immediately, having made an 
opening into the left side of the thorax, I tied a ligature round 
the base of the heart, so as to stop the circulation. The 
wound in the skin was closed by a suture. An opening was 
then made into the trachea, and the apparatus for artificial 
respiration being fitted into it, the lungs were inflated, and 
then allowed to collapse as in the former experiment, about 
3 6 times in a minute. This was continued for an hour and a 
half, and the temperature was examined at different periods. 
The temperature of the room being the same, I killed the 
second rabbit in the same manner, and measured the tem- 
perature at corresponding periods. The comparative temper- 
