Mr. Home’s Lecture 
1 6 
This experiment was repeated upon another horse; and the 
result was similar, both with respect to the contraction which 
took place after the nerve had been removed from the body, 
and the elongation which depended upon elasticity. 
To ascertain if there was any difference in the appearance of 
a nerve when contracted, from one in a relaxed state, the fol- 
lowing comparison was made. 
Exper. 6. A portion of the phrenic nerve, about eight inches 
long, was removed immediately after the horse had been 
knocked down. This was allowed to contract ; and, after it had 
remained quiet for twenty-four hours, its external surface was 
exposed by dissection, so that the appearance of its fibres could 
be distinctly seen. A portion of the same length was removed 
from another horse who died a natural death, and these were 
compared together. 
The difference in the appearance of these two portions was 
very great: in the contracted nerve, the fibres were all ser- 
pentine ; in the other, they were straight. The annexed plate, 
(see Plate!.) in which they are represented, shows very cor- 
rectly, the great contrast which they exhibited. 
The serpentine transverse lines described by Monro, appear 
to be an effect of this contraction of the nerve ; as they disap- 
pear when the nerve is relaxed or elongated.* These ser- 
pentine lines in the phrenic nerve, in a man who died of a 
locked jaw, when examined twenty-four hours after death, were 
much more distinct and regular than in the phrenic nerve of a 
man who died of a mortification of his arm. 
* « When the nerve is fully relaxed, these serpentine transverse lines are best seen % 
when the nerve is moderately stretched, they are much less evident ; when the nerve 
is greatly stretched, beyond what it ever is in a living sound animal, it appears 
