Page:Proceedings of the Royal Society of London Vol 1.djvu/54

Rh the progress of this irritation, which seemed to constitute the disease, it was proposed to divide the nerve as it passes from under the annular ligament of the wrist. This operation was accordingly performed, but 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 time after apparent death has taken place, and also to ascertain what proportion of elasticity 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 direction), 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 perve had been previously contracted in consequence of being divide po increase of that contraction was produced by the electric fluid, nor was any sensible effect perceived when the nerve had not been previously irritated.

During this investigation a singular case occurred, from which it appears that electricity is capable of depriving a nerve of all its functions 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 minutes after, while she was rubbing her eyes with her hand having a