is Mr. Home's Lecture 
in the body, both from its superficial situation in the chest, and 
its great extent without giving off any branches. 
In making experiments of this nature, it is an advantage 
that the animal should be of a large size ; and the mode in 
which horses are killed in London, affords an opportunity of 
experiments being made on that animal, without giving the 
operator the painful sensations of having made any addition to 
its sufferings. 
As horses are killed at stated times only, and these occur in 
a part of the day which is necessarily occupied by my profes- 
sional engagements, the following experiments were made by 
Mr. Clift, the Conservator of the Hunterian Museum, whose 
accuracy may be relied upon, as well as his abilities in con- 
ducting them, having been early initiated, and long experi- 
enced, in inquiries of this nature. 
Exper. 2. Immediately upon a horse having been knocked 
down, the thorax was laid open, and the phrenic nerve of the 
right side, passing round the pericardium, was exposed. It was 
nearly of the size of a crow-quill, and slightly connected with 
the pericardium. In this state, the point of one blade of a pair of 
scissars was passed under the nerve ; and, by closing them, the 
nerve was transversely divided, without the smallest disturb- 
ance to its lateral connections. The two cut ends immediately 
retracted from each other, leaving the space of one inch be- 
tween their extremities. 
This experiment was repeated upon a second horse; and the 
retraction of the cut ends of the nerve was found to be exactly 
one inch. 
It was repeated upon a third horse ; and the retraction was 
found to be nearly two inches. In measuring the space between 
