Experiments and Observations

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Fowler Richard. Experiments and Observations

SECTION I. Are the Phenomena, exhibited by the Applicationof certain different Metalsto Animals, referrible to Electricity?

SECTION II. Has Magnetism any concern in the Phenomena discovered by Galvani?

SECTION III. What are the relations which subsistbetween the influence discovered by Galvani, and the muscles, the nervous, and the vascular systems, of animals?

SECTION IV. An attempt to investigate the Source from which the respectivePowers of Nerves, and of Muscles, are derived

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The whole train of circumstances, which preceded this discovery, had a tendency to occasion the belief of its relation to electricity.

Some accidental appearances, certainly electrical, excited, by their novelty, the attention of the Professor of Anatomy at Bologna, to the investigation of the possible, but unknown, dependencies of the motions of animals upon electricity; and the astonishing effects of that influence upon the human body, particularly in paralytic diseases, whether owing to derangements of the nerves, or of the muscles; the experiments, which prove that the fluids of animals are better conductors of electricity, than water is; and that, “if an electric shock pass through a given part of a living animal, the same shock, after the animal is dead, will be visibly transmitted over the surface of the part, but not through it1:” the recollection, too, of that singular power, which some animals possess, as the torpedo, the gymnotus electricus, and the silurus electricus, of collecting and discharging at pleasure the electrical fluid; but, above all, the wonderful, but solitary, instance of an electrical shock received from a mouse, under dissection, recently related by his countryman Cotugno; were circumstances, which seem to have rendered the expectations of the Professor not a little sanguine as to his success.

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Contractions, however, certainly may be excited in different parts of a frog, without making any division of its skin, by laying the part of the frog to be excited upon a plate of zinc, or tin-foil, and passing a piece of silver over it, till all three are in contact with each other7. Yet even here the influence does not pass into the part in so diffused a state as it may at first appear to do. For the skin of these animals is abundantly supplied with nerves, whose trunks communicate, at different places, with those which supply the muscles. And the contractions are always strongest, and most readily excited, when the silver is passed over the course of any of the nerves, which go to the muscles.

From the fact, which I have before mentioned, that a limb may be made to contract, when the metals have apparently no communication with any part of it except its nerve; it might reasonably be doubted, whether, in any case, a communication between the muscles, as well as the nerve, and the metals, were necessary, in order that contractions may be excited.

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