The experimental method in medical science : second course of the Cartwright Lectures of the Alumni Association, College of Physicians and Surgeons, New York delivered January 24, January 31, and February 7, 1882 / by John C. Dalton.

  • Dalton, John Call, 1825-1889.
Date:
1882
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Licence: Public Domain Mark

Credit: The experimental method in medical science : second course of the Cartwright Lectures of the Alumni Association, College of Physicians and Surgeons, New York delivered January 24, January 31, and February 7, 1882 / by John C. Dalton. Source: Wellcome Collection.

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    understand it. Volta imagined the metals in his pile to act by contact alone, while they are really consumed by oxidation. In Galvani’s experiment, the connecting arc where the two metals join is, as Galvani supposed, a con- ductor, and nothing more; but its different extremities, when applied to the animal tissues, form with them a gal- vanic battery of a single cell, and thus produce the current which excites their contraction. We now use it for physi- ological purposes in a different way. We place the two metallic plates in a cup of acidulated fluid, and make the returning current pass through the muscles and nerve. But the effect is the same, for the active force of the cur- rent is equal in both directions. The results obtained by these two investigators were distinct from each other, but of almost equal importance. Galvani discovered the electric action on nerves and mus- cles which bears his name. Volta gave to science a new apparatus, by which current electricity is transmitted in a continuous circuit. Each investigator was partially at fault in the theoretical explanation of his own discovery. But the value of the discovery has remained, and has even largely increased in the course of a century, notwithstand- ing the difference in its interpretation. It also appears, from the history of the circumstances, that the second of these discoveries was a consequence of the first; and nothing can show more clearly the unbroken connection of events in the progress of science, which may some- times extend to the most unexpected ramifications. It is plain that we should not be to-day in possession of the electric light, were it not for Volta’s discovery of current electricity; and Volta produced his electric pile in trying to investigate the contraction of Galvani’s frogs. During the early part of the present century, experi-