63 
source of animal heat being in the nerves . 
In eight hours the heat of the left foot rose to 94 0 , probably 
from the increased quantity of blood circulating through its 
arterial branches, since next day the temperature fell to 88°, 
at which it continued stationary for four days ; the foot of 
the aneurismal side in 24 hours fell to 84°, but on the 
following day rose to 85 0 , and continued at or above that 
temperature till the ligature came away. 
Nothing can have been more satisfactorily proved than 
that the heat of the parts of the body is diminished by dividing 
the nerves going to them ; while, on the other hand, obstruct- 
ing the arterial trunk of the thigh, even before it sends off the 
great muscular branch, does not diminish the heat in the 
smallest degree below the natural standard. 
I have had many opportunities of ascertaining the tempe- 
rature of the foot after the femoral artery has been tied in 
the operation for the popliteal aneurism, and found it com- 
monly one degree below that of the other foot, but the heat 
of the two feet had never been ascertained before the opera- 
tion, so that I was most probably deceived in the conclusion 
I had drawn ; and in reality, the heat of the other foot had 
been raised above the standard, instead of having been 
depressed below it. 
