At the time I first observed this fact, I was making experiments to ascertain whether it was possible to transmit the influence, which had excited contractions in one leg, into another, removed to some distance from it, and communicating with it, only by means of a single conducting substance, (such as silver, for example). For this purpose, I had separated from the trunk, and from each other, the hind legs of a frog recently killed, and had detached their nerves as far as the knee. I then laid them at some distance from each other, upon a plate of glass, and included the nerve of one leg, and the foot of the other, in the folded ends of a silver chain. With one hand I now raised from the muscles, upon the end of a silver probe, the nerve of the leg, whose foot was folded in the chain; and with a piece of zinc, in the other hand, touched, at the same time, the nerve and the probe. This leg was thrown into strong contractions; but none were excited in the other. I then touched the chain, and nerve of the other, and, to my surprise, both legs instantly contracted. I had observed, in the beginning of November last, that it was not necessary for the metals to be in contact with any thing but nerve, in order to excite contractions in the muscles, to which it was distributed; and had mentioned this fact immediately afterwards to the Medical Society of this place, as a sufficient refutation of the theory, which Dr Valli had formed of Galvani’s discovery. It would not, therefore, have surpassed my expectations, had the influence, excited by the mutual contact of a piece of zinc, and probe, with the nerve, passed through the medium of the chain, from the leg, in which it first excited contractions, and produced contractions in the distant leg. But, I now thought that I had not only passed the influence from one leg to the other, but in one of the legs in a direction contrary to the course of its nerves. The removal of the leg, whose nerve communicated with the chain, convinced me of my error: but, at the same time, discovered to me a fact of much greater importance, than any with which I had hitherto been acquainted. For now, upon touching the chain alone with the zinc, I found that the leg, whose foot it still included, and whose nerve I held suspended upon a probe, contracted as strongly as before. The influence of the two metals, in contact with the nerve of the other leg, had not, therefore, passed into, and excited this.