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The Ambiguous Frog

The Ambiguous Frog: The Galvani-Volta Controversy on Animal Electricity

Marcello Pera
Translated by Jonathan Mandelbaum
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    The Ambiguous Frog
    Book Description:

    How do ideas become accepted by the scientific community? How and why do scientists choose among empirically equivalent theories? In this pathbreaking book translated from the Italian, Marcello Pera addresses these questions by exploring the politics, rhetoric, scientific practices, and metaphysical assumptions that entered into the famous Galvani-Volta controversy of the late eighteenth century. This lively debate erupted when two scientists, each examining the muscle contractions of a dissected frog in contact with metal, came up with opposing but experimentally valid explanations of the phenomenon. Luigi Galvani, a doctor and physiologist, believed that he had discovered animal electricity (electrical body fluid existing naturally in a state of disequilibrium), while the physicist Alessandro Volta attributed the contractions to ordinary physical electricity. Beginning with the electrical concepts understood by scientists in the 1790s, Pera traces the careers of Galvani and Volta and explains their laboratory procedures. He shows that their controversy derived from two basic, irreducible interpretations of the proper nature of a common domain: Galvani saw the frog phenomenon as the work of biological organs, Volta as that of a physical apparatus. The initial preference for Volta's theory, maintains Pera, depended not on clear-cut methodological rules, but on a dialectical dispute for which the renowned physicist was better equipped, partly because he shared the dominant metaphysical views of his time.

    Originally published in 1991.

    ThePrinceton Legacy Libraryuses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

    eISBN: 978-1-4008-6249-8
    Subjects: History of Science & Technology

Table of Contents

  1. Foreword
    (pp. xi-xiv)
    I. Bernard Cohen

    Until recently the early history of electricity has remained the almost exclusive province of historians of science, never becoming a primary topic of interest to philosophers to the degree that occurred in mechanics, heat, atomism, and other branches of physics. Now that situation has radically changed. The keen philosophical discernment of Thomas S. Kuhn has caused us to behold in a radically new way the diagrams in Volta’s dramatic announcement of the electric battery (or Voltaic cell) in 1800 (Kuhn 1987). In the work before us, Marcello Pera shows how a fresh examination of the Galvani-Volta controversy enables us to...

  2. List of Abbreviations
    (pp. xvii-xviii)
  3. Introduction
    (pp. xix-2)

    This book deals with an exemplary episode in the history of science: the controversy between the supporters of Luigi Galvani’s theory of animal electricity and its opponents, led by Alessandro Volta. The episode’s importance was aptly described by one of the scientists extensively involved in its early aftermath: “The storm aroused by the publication of [Galvani’s]Commentariusamong physicists, physiologists, and physicians can be compared only to the storm that at the same time [1791] arose on the political horizon of Europe” (du Bois-Reymond 1848, 1:49; see Hoff 1936, 159). And the enduring relevance of the controversy is demonstrated by...

  4. CHAPTER 1 Electricity, the Science of Wonders
    (pp. 3-37)

    Who knows what particular examples old Aristotle had in mind when he said that science begins with wonder. Electricity was almost certainly not one of them. Not that the philosopher was unacquainted with the properties of amber—or, as it was called in his language, ἤλεκτρον. By the time of Thales of Miletus (sixth century b.c.)—and possibly earlier—it was known that this stone, if rubbed even just with a dry hand, behaved oddly like a magnet, attracting bits of straw, dry leaves, and other light bodies. But, although familiar, these properties had never been methodically investigated. Nor had...

  5. CHAPTER 2 Volta’s and Galvani’s Scientific Training
    (pp. 38-68)

    On 1 February 1759, Robert Symmer, paymaster to the treasurer of the king of England’s Chamber and a quite talented scientist, delivered his first paper to the Royal Society, of which he had been a fellow since 1752. Symmer reported a new experiment that, although inelegant, seemed in his prophetic words “to open a new path for proceeding in electrical researches” (1759,341). The scientific novelty of the experiment resided in the fact that two insulating bodies, when electrified in opposite ways, lost all sign of electricity when brought joined together, but regained their electrical charge when drawn apart. The inelegant...

  6. CHAPTER 3 Galvani’s Experiments and Theory
    (pp. 69-95)

    In his search for proof, Galvani soon stumbled on an important experiment performed “by chance” (Galvani was later to report several serendipities of this kind, sometimes with an exaggeration that has misled his interpreters). TheGiornalegives the date of the experiment as 26 January 1781—the last in a series begun on the 17th. The previous experiments recorded did not yield any noteworthy findings; in fact, they concerned the direct applications of electricity commonly studied by contemporary physiologists. The experiment of 17 January was, instead, of a special nature and led Galvani nine days later to the discovery of...

  7. CHAPTER 4 Volta’s First Reaction
    (pp. 96-116)

    How was theCommentariusreceived? Let us limit ourselves to early local reactions. All voiced admiration and wonder, but caution prevailed, at least among the most authoritative scientists. The exception was an endorsement from Spallanzani, the probable author of theTransunto, a partial annotated Italian translation of theCommentarius(S 1792).

    Among physiologists, the leading figures who had already studied the question were not greatly disturbed by Galvani’s experiments, and tended to reassert their views. Fontana wrote to Marc’Antonio Caldani on 16 May 1792:

    I have read Galvani’s work on animal electricity and have repeated most of his experiments, which...

  8. CHAPTER 5 The Crucial Experiments
    (pp. 117-145)

    The theory of animal electricity and the theory of contact electricity inevitably divided the scientific community. Although the closing years of the century were pregnant with momentous political processes and events, the vogue for electricity persisted and the connections between laboratories, learned societies, andsalonsremained intact. As du Bois-Reymond aptly put it:

    The storm aroused by the publication of theCommentariusamong physicists, physiologists, and physicians can be compared only to the storm that at the same time [1791] arose on the political horizon of Europe. It can be said wherever there were frogs, and wherever two dissimilar metals...

  9. CHAPTER 6 The Pile
    (pp. 146-176)

    In 1797, a year before his death, Galvani took up his pen for the last time to draft the fiveMemorie sull’elettricità animaleto Lazzaro Spallanzani. Their purpose was to refute Volta’s theory “with new considerations and new attempts.” At a certain point, however, in the second memoir, he examined what obviously appears to be a compromise hypothesis. This consisted in admittingtwotypes of electricity—“animal electricity” and “common electricity”—and consequendy two causes of contractions in the frog, a natural one and the one induced by “artifices.” “Such a supposition would have made Signor Volta’s opinion very compatible...