An Account of the Late Improvements in Galvanism. Giovanni Aldini
that of the atmosphere. Until it be proved that the absorption of oxygen in the above experiments is merely a chemical effect, altogether unconnected with the action of Galvanism, I think I may be allowed to avail myself of it to prove the proposed analogy.
EXPERIMENT VI.
The ingenious theory of Girtanner, who ascribes the cause of muscular contractions to oxygen, the curious experiments by which Professor Humboldt revives the muscular force, by means of oxygenated muriatic acid, and those made by the celebrated Fourcroy on the same subject, induced me to examine the effect resulting from a combination of oxygen with muscular fibres, in a state of the greatest vitality. For this purpose, I adapted to a bell-glass a bent metallic wire, from which were suspended fourteen frogs, prepared with the utmost dispatch, and almost at the same instant, by myself and several of my pupils; and having formed an insulated plenum, I found, at the end of twenty-four hours, that the water had risen in the bell to the height of about half an inch.
EXPERIMENT VII.
I repeated this experiment, with the same success, on warm-blooded animals. I provided, for that purpose, the extremities of different pullets from which the crural nerves had been previously separated, and found that the elevations of the water, in the insulated plenum, were much less when I employed the fibres of these animals after their vitality had been weakened.
EXPERIMENT VIII.
Having obtained the bodies of some executed criminals, I exposed to the action of an insulated plenum the nervous and muscular fibres, and the substance of the brain. The elevations of the water were remarkable, in consequence of the different substances subjected to experiment, which, according to their different characters, exercised a different action on the oxygen. This fact ought to induce physiologists to undertake experiments of a similar kind with other gases, to enable them to determine the strength of the affinity exerted by animal substances to combine with oxygen.
EXPERIMENT IX.
As fishes, and in particular the torpedo, furnish a large quantity of animal or Galvanic electricity, I was inclined to think they would exhibit the before-mentioned effects in a very striking manner in an insulated plenum. I mentioned to Professor Mojon of Genoa the experiment I proposed to make; and, in a letter which I lately received from him, he informed me of the result, as follows:
“I took a strong torpedo, and, as soon as it was dead, armed its nerves with the usual armature. Having then placed it on an insulating stool, a little elevated above water, I covered it with a bell-glass the content of which was equal to 432 cubic inches. At the end of some hours I observed, with great surprise, that the water under the insulated plenum began to rise progressively during about ten hours; and at the end of forty-eight I found that it had risen an inch; so that it occupied a ninth part of the capacity of the bell, that is to say, forty-eight cubic inches. I analysed the remaining air, and found that the bell contained no more than 80 cubic inches of oxygen gas, and 324 of azotic gas; and that, during the above period, more than two-fifths of the oxygen gas contained in the bell had been absorbed.”
I propose going to the sea-coast, in order that I may repeat the experiment on the torpedo without any armature; and I shall embrace that opportunity of making various researches in regard to the new theory of Galvanism. I think it necessary, in general, to submit to new experiments the different animal parts immersed in the different aëriform fluids, fixing their various combinations according to the degrees of Galvanic force which they may possess.
PROPOSITION IX.
Flame prevents the action of the Leyden flask, as well as that of the pile, and also muscular contractions.
EXPERIMENT I.
I placed a lighted taper on an insulating stool; and having made the wire, proceeding from the interior coating of a charged Leyden flask, to pass through the flame, I found that, without forming an arc, it lost a portion of its electricity. If the experiment be repeated in such a manner that the flame makes a part of the arc between the two coatings, the flask is entirely discharged, without the arms of the person who forms part of the arc experiencing the least shock.
EXPERIMENT II.
I adapted to the summit of the pile a circular brass vessel, containing spirit of wine. By these means the pile was made to terminate in a strong flame, to which I applied a metallic conductor, while with the other hand I touched the bottom of the pile. The Galvanic fluid still withstood my efforts; and the case was the same when I substituted for the spirit of wine the flame of a common candle. It is proper here to remark, that the flame did not lessen the action of the Galvanism when the conductor, instead of being applied to the flame, was applied to the plate at the summit of the pile.
EXPERIMENT III.
I have already proved by a series of experiments, addressed to C. Lacepede, that flame made to form part of the arc applied to the nerves and muscles of a frog, prevents muscular contractions. I repeated the experiment, with the same result, on several warm-blooded animals. I observed that the flame interposed in the arc, which touched the back and belly of the torpedo, prevented the electric shocks.
PROPOSITION X.
Certain fluids, applied to the whole surface of the pile, or of animal parts, do not prevent the action of Galvanism.
EXPERIMENT I.
Two years ago, I made various experiments on this subject at Florence, with the celebrated Fontana; and we found that a pile, composed of a hundred plates of zinc and silver, after being immersed some time in common water, still exercised a very strong action. Professor Fontana informs me, in a letter, that he has performed the same experiment several ways, and always with the same success.
EXPERIMENT II.
Being desirous to examine the nature of the element inhabited by the numerous family of fishes, which are also subject to the influence of the Galvanic processes, I filled with sea-water thirty earthen vessels; and having formed a communication between them, by means of heterogeneous arcs, composed of brass and zinc, I obtained a shock, which appeared to me stronger than that obtained with artificial salt water. By establishing an arc with only five of these vessels, the action was very sensible. A pile composed of pieces of pasteboard, moistened with sea-water, and entirely immersed in the same water, gave, when tried, very strong shocks.
EXPERIMENT III.
I was able to prove the action of the Galvanic pile and of metals under water, by the following simple experiment: I placed a plate of zinc at the bottom of a vessel filled with salt water, (Plate II. fig. 6.). A person then brought the spinal marrow of a frog into contact with the surface of the salt water; and another person, absolutely insulated, touched with a silvered copper wire the plate of zinc. Every time that the wire was brought into contact with the zinc, muscular contractions took place. I am well aware, that the advocates for metallic electricity will deduce from the plain statement of this fact, an induction contrary to Galvanism; but my candour, on this occasion, will show how much I am attached to the cause of truth.
EXPERIMENT IV.
Among animal bodies, the torpedo is one of those which produce the most powerful Galvanic action. In the autumn of 1801, I made some experiments on this animal at Genoa, in conjunction with Professor Mojon and his brother, who gave me every assistance in their power. When I touched the torpedo, under water, at the moment when it gave the shock, it contracted itself, and two jets of water proceeded from the two holes in its head. To obtain the shock, it was not necessary to touch two distinct parts of its body: in many cases, the application of the hand to the electric organ was sufficient.
PROPOSITION XI.
Mere electrization, by means of the common kinds of apparatus, does not increase the action of Galvanism.
EXPERIMENT I.
Artificial electricity was communicated to an apparatus, composed of a hundred cups, care being first taken to insulate the table and the persons who were afterwards to receive the action of it. If we suppose that the heterogeneous arcs were charged with