Commentary on the Effect of Electricity on Muscular Motion

...d; completing the word "prepared" from the previous page for it is easy to be deceived in experimentation, and to think we have seen and discovered what we desire to see and discover.

But when I had moved the animal into a closed room and placed it on an iron surface, and began to press the hook fixed in the spinal cord against that surface, behold! The same contractions, the same movements appeared. I immediately performed the same test using other metals in other places, and at different hours and days; the result was the same, except that the contractions varied according to the difference in the metals—namely, more violent in some and weaker in others. It then occurred to me to try other bodies that conduct little or no electricity, such as glass, gum, resin, stone, and wood (provided it was dry); when these were applied to the same experiment, nothing similar happened, and no muscular contractions or movements could be seen. This outcome truly brought us no small amount of wonder, and began to stir a suspicion in me regarding an electricity inherent in the animal itself. This suspicion was increased by the observation of a kind of circuit of very thin "nerve fluid" original: "fluidi nervei"; Galvani believed a vital fluid flowed through the nerves, similar to electricity, which we noticed by chance happening from the nerves to the muscles while the phenomenon occurred—a circuit similar to the electric circuit that is completed in a Leyden jar original: "leidensi phiala"; the first device used to store static electricity, consisting of a glass jar coated with metal foil.

For while I held the prepared frog in one hand by the hook fixed in the spinal cord, so that its feet rested on a silver box original: "capsula", and with the other hand I struck the surface of that box (on which the frog's feet rested) or its sides with some metallic object, I saw to my surprise that the frog fell into significant contractions; indeed, this happened as many times as I used that same technique.

Having seen these things, I asked Rialp, a very learned Spanish man and formerly a member of the Society of Jesus The Jesuits, known for their scientific and educational work before their temporary suppression in the late 18th century, who was then staying in the country with me at the villa of the excellent and most noble man Giacomo Zambeccari. I asked him, I say, to lend a helping hand in this work (as he was kindly accustomed to do in other experiments) and to hold the frog just as I had done before, while I struck the box again—partly for convenience, and partly to vary the method of the experiment for a moment. But, contrary to expectation, the contractions failed to occur; I immediately set up the experiment as before and by myself, and they returned at once.

This truly moved me to [hold] the animal with one hand, as [before]...