Commentary on the Effect of Electricity on Muscular Motion

For example, once a certain extension of the nerve conductor is found that is sufficient for the effect, if you decrease this, the contractions do not just decrease, but fail entirely; if you increase it, the contractions indeed become stronger, but only until a certain extension is reached. Beyond that point, no matter how much further you extend the nerve conductor, the contractions are hardly increased at all—if at all. The same can be said regarding the other elements of the proportions we have set forth.

However, seeing such a great power in the sparks drawn from the machine's conductor to excite muscular movements, we expected even greater contractions from that electrical flame which erupts when a magic square original: "quadratum magicum". Also known as a Franklin Square, this was an early form of capacitor consisting of a pane of glass coated with metal foil on both sides. is discharged. But the result was quite the opposite; to our surprise, no movements occurred in the animal prepared in the usual manner.

Having tested these things with positive electricity In the 18th century, "positive" electricity was thought to be an excess of "electric fluid," while "negative" was a deficit., as they say, it seemed necessary to try similar experiments with negative electricity. First, we insulated the electrical machine and the person who was turning it. This person held an iron cylinder in his hand, toward which we brought the frogs, equipped with their conductors as needed. The frogs were placed on a glass surface so that nearby bodies would not contribute any electricity to them. Then, the person turning the machine deliberately drew sparks from nearby objects using the aforementioned iron cylinder. We saw contractions in the prepared frogs just as they occurred when sparks were drawn from the conductor of a machine that was not insulated.

We also tested negative electricity in another way, which was as follows. At a certain distance from the negative surface of a Leyden jar|An early device for storing electricity, consisting of a glass jar coated with metal foil on the inside and outside., we placed the nerve conductor C (Fig. 4). Then, we drew sparks from the "charged" surface (as physicists say), or from the surface endowed with positive electricity (Fig. 5). The frogs moved in the same way as when positive electricity was used. They even moved although the iron wire that formed the nerve conductor was not distant from the outer surface of the jar, and although the whole frog was enclosed in a long glass tube, and the frog itself was kept in a glass vessel, provided the open end of this tube was fitted against the aforementioned outer surface of the jar. Furthermore, these same contractions were obtained whether the spark was drawn from the hook of the Leyden jar at the very moment the jar was being "charged," as they say, or a little while after, or whether it was drawn at that...