I have before said that if a living and entire frog be set upon a plate of zinc, contractions can very seldom be produced in any part of its body by passing a rod of silver over it, so that the silver, the frog, and the zinc, may be all in contact with each other. But, I have found in upwards of twenty experiments, that when inflammation had been excited in one of the hind legs of a frog, by irritating it with a brush, contractions uniformly took place in that leg when the metals were applied to it, although none had been produced in it before it was inflamed, nor could still be produced in the other leg which remained in its natural state. EXPERIMENT II. Having previously excited inflammation, by means of a brush, in the foot and leg of a healthy and large frog, I cut off its head. The contractions excited by the metals in the inflamed leg were in vigorous and instantaneous jirks; those in the sound leg more languid and difficultly excited. Spontaneous motions continued at this time nearly the same in both. Till the end of the second day, after this frog’s head had been taken off, the contractions excited in the inflamed leg continued uniformly, and beyond all comparison more vigorous than what I could by any means excite in the sound leg. But, after this time, the inflamed leg became hard as a piece of wood; probably in consequence of the effusion to which the inflammation had given rise. The event of five similar experiments was so nearly the same, that I should be thought unnecessarily minute, were I to relate them in detail. We are now perhaps prepared to account for the deficiency of contractile power in those legs, whose sciatic nerves had been divided, the one, between three weeks and a month, the other, six weeks, compared with its continuance in the leg, whose nerve had been divided upwards of three months. It appears, from the circumstances of those experiments, that some of the arteries, appropriated to the supply of the sciatic nerves of frogs, have the same course with the nerves themselves; since the deposition of new matter could in all be traced from the upper division of the nerves. It is obvious, therefore, that the part of the nerves below the division, must have been deprived of so considerable a portion of their usual arterial supply, as in time would occasion some alteration in their structure, and consequently in their powers. We accordingly find that such alteration of structure, and such deficiency of power, had actually taken place. It is further probable, that, in proportion as the supply from the arteries was restored, the powers of that nerve, which had been three months divided, had been likewise restored. This supposition is countenanced by every instance in which nerves are reproduced; as we find the functions of the parts in which they had been divided, are not immediately, but gradually restored.