34. 



the progress of this irritation, which seemed to constitute the disease, 

 it was proposed to divide the nerve as it passes from under the an- 

 nular ligament of the wrist. This operation was accordingly per- 

 formed, hut not altogether with the desired success, owing probably 

 to the wound not healing by the first intention. 



Among several singular circumstances in this case, we find also a 

 retraction which took place in the cut ends of the nerve at the time 

 of the operation ; and the first idea that suggested itself, was to en- 

 deavour to ascertain whether this effect arose from an increase of a 

 natural action in the nerves, or of one newly acquired and entirely 

 produced by the disease. Various experiments were accordingly 

 made on the cutaneous nerves of rabbits, and the phrenic nerve of 

 horses immediately after they were killed. The results were, that a 

 considerable retraction always took place, and that any action the 

 nerves are capable of exciting is nearly as strong after apparent death 

 has taken place from a violence committed upon the brain (the horses 

 having been killed by such means), as while the animal is in perfect 

 health. 



As it might be suspected that the cellular membrane is the agent 

 by which this retraction of the divided nerves is produced, further 

 experiments were made in such a way as to prevent any other sur- 

 rounding part from acting upon the nerve. Other experiments were 

 also attempted, with a view to determine whether the power of con- 

 traction in a nerve continues for any length of tune after apparent 

 death has taken place, and also to ascertain what proportion of elas- 

 ticity may be possessed by the nerves. The results were, 1 . That 

 in all cases the nerves of an animal in health are capable of retracting 

 themselves when divided, and that this effect is entirely independent 

 of the parts by which they are surrounded. 2. That this contraction 

 takes place in the nervous fibres themselves, and is independent of 

 the brain from which they originate, and the muscles and other parts 

 in which they terminate. 3. That the contracted nerve exhibits to 

 the eye an appearance of contraction (a serpentine or undulated di- 

 rection), which does not appear when the nerve is in a relaxed state. 



As the nerves are so easily influenced by electricity in exciting the 

 muscles to action, it naturally suggested itself that some further in- 

 formation might be obtained in the present investigation, by means 

 of experiments made upon the nerves by the electric fluid. From a 

 number that were made for the purpose, it appeared that when the 

 nerve had been previously contracted in consequence of being divided, 

 no increase of that contraction was produced by the electric fluid, nor 

 was any sensible effect perceived when the nerve had not been pre- 

 viously irritated. 



During this investigation a singular case occurred, from which it 

 appears that electricity is capable of depriving a nerve of all its func- 

 tions for a certain time, without destroying them entirely. A young 

 woman, while in the act of bolting the window- shutter, was struck 

 across the eyes by lightning, and a second flash struck her a few mi- 

 nutes after, while she was rubbing her eyes with her hand having a 



