Being desirous to confirm the theory of the Galvanic atmosphere, I placed in it the body of an executed criminal. I removed the pile to the distance of a foot from the trunk, without the usual communication of metallic arcs; and having made an incision in each ancle, two persons held two frogs prepared in the usual manner, in such a position that the spinal marrow rested on the incisions. When matters were thus arranged, every time that a third person touched the summit of the pile, both the frogs experienced violent contractions, and to such a degree, that, leaving free one of the extremities, a real electrico-animal alarum was obtained, perfectly similar in its effect and identity to that described by Galvani in his Commentary. When the metallic apparatus is employed, if one of the persons who holds a frog be insulated, the frog will remain motionless, while the other will experience the usual effect. I had an opportunity of confirming the truth of this observation, on the trunk of a dog, during a course of experiments made in the _Hôpital de la Charité_, at Paris, and at St. Thomas’s Hospital, London. PROPOSITION XV. _Opium, cinchona, and other stimulants of a similar kind, which exercise a powerful action on the animal machine, contribute also to excite the action of the pile._ EXPERIMENT I. In the last sitting of the Institute of Bologna, at which I was present, I constructed two piles, each composed of fifteen pieces of silver and zinc, employing for the one an extract of opium, and for the other an infusion of cinchona in alcohol. I covered the piles with two equal receivers; formed an insulated plenum, by pouring mercury around the bottoms of them; and placed weights on the receivers sufficient to prevent the mercury from raising them. At the end of some hours, I found a remarkable elevation of the surface of the mercury, so that the receivers remained fixed without requiring any weight to keep them down. In the bell which covered the pile where extract of opium had been employed, the mercury rose more than an inch; but in that covering the other, where cinchona had been used, the elevation of the mercury was scarcely three lines. EXPERIMENT II. Having successively introduced a taper into each of the two receivers before mentioned, it was immediately extinguished in that containing the pile with the extract of opium; but in the other containing the pile with the infusion of cinchona, it continued burning for some time. I found also that four of the plates, at the bottom of the pile where I employed opium, had suffered from the action of the mercury; and that some others, to the height of about three inches and a half, exhibited a few globules of that metal. The pile in which I employed infusion of cinchona showed scarcely any signs of the action of the mercury. EXPERIMENT III.