THE HISTORICAL DEVELOPMENT OF NEUROPHYSIOLOGY 



Kamin in Pomerania, yet another of the indefatigable 

 company of eighteenth century clergymen to whom 

 science owes so much. 



Both the electroscope and the Lcsclen jar were 

 used by Galvani in the experiments he had begun 

 not later than 1 780. He was also familiar with the 

 fact that some animal forms, notably the marine tor- 

 pedo and the electric eel, had intrinsic electricity. 

 Scientific studies of this type of animal electricity 

 had begun with the work of John Walsh (73) in 1733 

 and have continued to this day. In those days the 

 production of a spark was considered a sine qua non 

 for full acceptance of the electrical nature of a 

 phenomenon; this was lacking for the fish until after 

 Gahani's time when Matteucci developed a tech- 

 nique for demonstrating it (see fig. 12). For many 

 years before Galvani's day, as demonstrated for 

 example by Swammerdam and by the French anato- 

 mist Joseph Guichard Duverney,^^ it had been known 

 that the limbs of a frog could be convulsed by me- 

 chanical irritation, and electricity applied directly to 

 the muscle already had been used by many phy.sicians 

 (and quacks) to animate paralytics. 



The three chief observations that stand out from 

 the many experiments reported by Galvani in his 

 original Commentarius (74) were a) that a frog's nerve 

 muscle preparation, although at a distance from a 

 sparking electrostatic machine, would twitch when 

 touched by an observer (in the light of later knowledge 

 this was called induction at a distance, with stimula- 

 tion occurring by the 'returning stroke' at the moment 

 of sparking); *) that atmospheric electricity could be 

 used to stimulate frogs' legs if a long wire were erected 

 (the principle of the lightning conductor); and c) that 

 frogs' legs twitched when hung by brass hooks to an 

 iron railing even in the absence of a thunderstorm. 

 This last, the most important discovery in his first set 

 of experiments, was due to the current that flows be- 

 tween dissimilar metals when connected in a circuit, 

 though Galvani did not understand this at the time 

 and attempted to explain all his results as the presence 

 of intrinsic animal electricity. 



The Commentartus was reprinted three times, twice 

 in 1 791 and again in the turimlent year i 792 (the year 

 that France seized Savoy); then it reached scientists 



73. Walsh, John (1725-1795). On the electric property of 

 the torpedo. Phil. Trans. 63: 461, 1773. 



74. Galvani, A. (1737- 1798). De viribus electricitatis in 

 motu musculari. Comment ar his De Bononiensi Scientiarum el 

 Artium Insliluto alque Academic Commenlarii 7: 363, 1 791; 

 English translation of 2nd reprinting of Galvani's Com- 

 mentary by M. G. Foley. In: Galvani: Effects of Electricity 

 on Muscular Motion. Norwalk: Burndy Library, 1954. 



FIG. 12. Galvani and the experiment on muscle contraction 

 in the absence of any metals. The portrait is from the contem- 

 porary oil painting in the Library of the University of Bologna 

 (reproduced by courtesy of Dr. G. Pupilli). The experiment 

 in which one leg is being stimulated by touching the nerves 

 from the severed spinal column is reproduced from Aldini's 

 book, Essai sur Ic Galvanisme. Paris: Piranesi, 1804. 



outside Italy. Through the great controversy stirred 

 up by Volta which continued after Galvani's death in 

 1798 (Galvani's less prudent nephew Aldini cham- 

 pioning his cause), two extremely important areas of 

 knowledge developed from the original observations. 

 One was the recognition and elucidation of the 

 electrical properties of mu.scle and ner\'e which were 

 to lead directly to the discovery (by du Bois-Reymond 

 in the next century) of the action potential of nerve, 

 and the other was the developinent (by Volta) of bi- 

 metallic electricity into the electric battery, one of 

 the major technological steps in the history of science. 

 Volta had striven to explain all the frog experiments 

 by bimetallic currents, insisting that to produce elec- 

 tricity three substances were always necessary, two 

 heterogeneous metals and a third conducting material 



" This, one of the early public demonstrations of the stimula- 

 tion of muscle through irritation of its nerve, was made before 

 the Academic Royalc de Sciences in Paris in 1700, and is 

 reported for that year as follows: "M. Du Verney shewed a frog 

 just dead, which in taking the nerves of the belly of this animal 

 which go to the thighs and legs, and irritating them a little 

 with a scalpel, trembled and suffered a sort of convulsion. 

 Afterwards he cut these nerves in the belly, and holding them 

 a little stretched with his hand, he made them do so again by 

 the same motion of the scalpel. If the frog has been longer dead 

 this would not have happened, in all probability there yet 

 remained some liquor in these nerves, the undulation of which 

 caused the trembling of the parts where they corresponded, 

 and consequently the nerves are only pipes, the effect whereof 

 depends upon the liquor which they contain." History and 

 Memoirs of the Roy. Acad. Sci. Paris. Translated and abridged by 

 John Martyn and Ephraim Chambers. London: Knapton, 

 1742, p. 187. 



