on Animal Heat. 
595 
arterial 1049 ; and hence allowing, as before, one d<^gree of the 
cooling effect to be produced by the receiver, the capacity of 
venous blood for heat appears to be .852, and that of arterial 
blood .839. 
It is evident that these trials admit of less accuracy than the 
preceding ; and much more confidence, it appears to me, is 
due to the third series of experiments, so that if required, I 
should be inclined to give the numbers thence deduced, as the 
greatest approximation to the truth, • 
2. On the comparative teinperatures of venous and arterial Bloody 
and of different parts of the animal body. 
To endeavour to ascertain the comparative temperature of 
venous and arterial blood, I have made a considerable number 
of experiments ; some of which on lambs, sheep, and oxen, it 
will be sufficient for me in this place to describe. In each in- 
stance, a long incision was made through the integuments ; 
the jugular vein was laid bare, and the exact seat of the carotid 
artery found. The vein was then opened, and a small delicate 
thermometer introduced, and thrust about an inch up the 
vessel beyond the wounded part, and as the bulb of the in- 
strument was small, the flow of blood was not stopped. When 
the mercury was stationary, its height was marked. The 
carotid artery next was divided, and the thermometer was 
immersed in the current of blood, and left there till it ceased 
to rise. 
The following are the results of five experiments made on 
lambs, all of which w^ere about three months old. The ther- 
mometer in the shade stood at 65. 
