Commentary on the Effect of Electricity on Muscular Motion

Having observed these things, it became clear to us that not only is a conducting body applied to the nerves required, but also a certain size and extension of that body is necessary for the phenomenon to occur. For the sake of clarity rather than brevity, we shall henceforth refer to a conductor of this kind as the conductor of the nerves.

To the end of this conductor, we attached a frog by means of a very small hook fixed into its spinal marrow (Fig. 2). We then placed the frog sometimes toward the machine original: "machinam". This refers to an electrostatic generator, a device used in the 18th century to generate static electricity via friction., and at other times we positioned its conductor in such a way that the frog was sometimes near the machine and sometimes far away from it. Consequently, sometimes the feet and at other times the prepared nerves were turned toward the machine; sometimes the frog had the conductor in front of it and sometimes behind it. Nevertheless, the contractions were always obtained in the same manner.

We further investigated whether the phenomenon could be obtained in prepared animals even at a great distance from the machine by using very long conductors of the nerves. The experiment reached the point where, by using an iron wire a hundred or more cubits original: "ulnas". A historical unit of measurement; an "ell" or "cubit" was roughly the length of a man's arm. long, contractions of the muscles still occurred at that great distance from the machine whenever a spark was drawn. We conducted the trial in this manner: we suspended an iron wire F F (Fig. 3) by silk threads and—as physicists say—we insulated insulavimus: to isolate an object with non-conducting materials (like silk) so that electricity cannot escape to the ground. it. We fastened one end to a nail fixed in the wall (F) using silk threads as well, and extended the other end far from the machine, through several different rooms, according to the length of the wire. To this, we joined another iron wire B at point C, from the end of which a frog was suspended. For convenience, we enclosed the frog in a glass vessel A, the bottom of which we had filled with a conducting material—water, for example, or very small lead shot original: "globuli plumbei venatorii". Galvani found that lead pellets provided a better electrical connection than water for the frog's feet., which made the experiment work better. When a spark was drawn from the machine's conductor, it was truly marvelous to see the truncated frog move and almost leap up at such a great distance. The same thing happened if the frog was removed from the glass vessel and hung from conductor E E in the same way; the reaction was even swifter if some conducting body connected to the ground was attached to its feet.

Once we had confirmed this using an insulated conductor, we explored what would happen with a non-insulated one.

For this purpose, we fastened the same iron wire E E to various door hinges in the rooms of our house, which