Sir Everard Home on the influence of 
fore us to direct the operation. These were found to be the 
frontal branch of the fifth pair, and the branch of the fifth 
belonging to the first division which ascends on the outer 
part of the orbit : this branch in the human body is joined 
by the trunk of the portio dura of the seventh pair, but in 
the deer it has no such connection. 
Each of these trunks were laid bare by Mr. Mayo in the 
most satisfactory manner, and a probe passed under the 
nerve, which was then divided, just where they emerge on 
leaving the great ganglion, which is close to the brain. 
That any difference in temperature of the two horns which 
should occur after the experiment might be registered in 
the most accurate manner, a hole was bored quite through 
each of the horns at an equal distance from the tip, just large 
enough freely to receive the ball of the thermometer. 
An hour after the nerves were divided, which was about 
three o^clock of July the 21st., the temperatures were ex- 
amined, and so on once a day as long as there was a mate- 
rial difference between them. This will appear by the fol- 
lowing diary, only to have continued for five days. 
July 21, 
Atmosphere. 
66° 
Unnerved Horn. 
72° 
Uninjured Horn. 
- 84° 
22 
64 
- 
69 
- 95 
23 
64 
- 
67 
84 
24 
64 
- 
76 
84 
25 
67 - 
- 
87 
- 90 
Forty-eight hours after the nerves were divided the tem- 
perature of the horn was only 3® higher than that of the 
atmosphere. 
From the time the experiment was made the deer was 
