*3 
on the Irritability of Nerves. 
the two ends of the nerve, the compasses accidentally touched 
the lower portion, and the diaphragm was immediately thrown 
into action. 
The result of this experiment, not only confirmed the for- 
mer, which had been made upon the rabbit, but it proved in 
the most satisfactory manner, that any action the nerves are ca- 
pable of exciting, is nearly as strong after apparent death has 
taken place from a violence committed upon the brain, /as while 
the animal is in perfect health. 
Monsieur Portal, in a paper on a new mode of perform- 
ing the operation of amputation, published in the Memoirs of 
the Academy of Sciences for the year 1773, mentions an expe- 
riment made on the sciatic nerve of a dog, in proof of nerves 
not having a power of retraction, at least none deserving of 
notice.* 
t 
This experiment was repea ed by Mr. Clift, on the sciatic 
nerve of a rabbit. Immediately on dividing the nerve, the cut 
ends receded from one another : but, that the result might be 
exactly ascertained, the rabbit was killed half an hour after the 
experiment was made ; the parts were carefully dissected, and 
the space between the two cut ends measured; which was 
exactly of an inch. 
To ascertain whether this retraction was the consequence of 
a change taking place in the nerve itself, or arose from any 
other cause, the following experiment was made. 
Exper. 3. As soon as a horse was knocked down, the chest was 
laid open, and the phrenic nerve of the right side was exposed : 
twelve inches in length were immediately measured by a pair 
* Memoire sur une nouvelle methode de pratiquer 1 ’ Amputation des Extremites, 
par M, Portal. Histoire de VAcademie des Sciences , 1773, p„. 542. 
