THE HISTORICAL DEVELOPMENT OF NEUROPHYSIOLOGY 



strated that, although electricity passed through the 

 damaged zone, mechanical stimulation of the nerve 

 above the injury provoked no twitch. 



During the era of intense concentration on electro- 

 physiology in the Italian and German schools, labora- 

 tories in other countries were developing a different 

 approach. Among these was that of Claude Bernard 

 (95), pupil of Magendie. Claude Bernard made use of 

 curare as a blocking agent, interpreted by him as a 

 nerve poison that spared the muscle. He found that 

 in a curarized preparation the muscle would not 

 twitch if he stimulated it directly and hence concluded 

 that normally transmission could not be electrical 

 either. In these experiments he used the ingenious 

 little stimulator built from a Voltaic pile of alternate 

 copper and zinc plates that is shown in figure 16. 

 He did not recognize that his failure to evoke a con- 

 traction by direct stimulation of the muscle was due 

 to his 'pile' giving too feeble a current. 



Miiller was the last of the great physiologists to 

 retain a trace of vitalism in his thinking. This he 

 probably owed to his exposure as a student at Bonn 

 to Natiirphilosophie and the influence of its leader, 

 Schelling (96). Although more extensively indoc- 

 trinated in this sterile philosophy than Oersted had 

 been, Miiller was later able to free himself more ea,sily 

 from its stultifying effects, and he eagerly encouraged 

 the physical and chemical approaches to biological 

 experiment. Not a trace of vitalism is found in his 

 pupils. 



Towards the half-century a marked swing away 

 from the metaphysics of Natiirphilosophie char- 

 acterized neurophysiology, du Bois-Rcymond con- 

 sidered himself (and with some right) to be the 

 champion of this movement which strove to explain 

 all physiology on chemical and physical grounds. 

 And in fact, as we have .seen, it was the physicists of 

 the period who were contributing most of the new 

 experiments and concepts of muscle and peripheral 

 nerve action. Before this, neurophvsiologists had 

 reached a stage in their work in which progress was 

 hampered by lack of sufficiently sensitive instruments. 

 The physicists came to their help and indeed were 

 themselves intrigued by the types of physical phe- 

 nomena that biological preparations provided. 



In 1841 du Bois-Reymond received from his 



95. Bernard, Claude (1813-1878). Lf(,ons sur la phynoloiie 

 el la pathologie du systeme nerveux. Paris: Bailli^re, 1B58. 2 vol. 



96. Schelling, Frederick Wilhelm Joseph (i 775-1854). 

 Sammiliche Werke. .Stuttgart and Augsburg, 1856-1861, 

 14 vol.; English translation of vol. Ill by T. Davidson. 

 In J. Specula! . Philos. I: 193. 1867. 



% 



\ I 



FIG. 16. Claude Bernard at the age of 53, and the ingenious 

 stimulators he used in his electrophysiological studies of nerve. 

 They were miniature voltaic piles built up of alternate discs of 

 copper and zinc. Just before use they were moistened with 

 vinegar. Such dc\ices were made obsolete by the du Bois- 

 Reymond induction coil and it is rather surprising to find 

 Bernard still advocating them in his day. Although adequate 

 for nerve stimulation, they gave too feeble a current to stimulate 

 a muscle directly; from this Bernard concluded that the nervous 

 effect on muscle could not be electrical. 



master a copy of Matteucci's book Essai sur les 

 Phenomenes Electriques des Animaux (97), together with 

 the suggestion that he repeat and extend Matteucci's 

 experiments. By November of that year he had al- 

 ready completed a preliminary note C98), but his 

 major work, the Thierische Elektricitdt C99)j did not 

 appear until 1848. The first part of this long and de- 

 tailed book, unlike its later sections, shows little 

 originality in scientific ideas, the author with a chip 

 on his shoulder being carried along in the wake of 

 Matteucci of whose publications he was outspokenly 

 critical. However, where du Bois-Reymond shines, 

 and what makes his book a classic, is his skill in in- 

 struinentation, far surpassing that of Matteucci, so 

 that he was able to extend and improve on these 

 earlier observations. Moreover, not being hampered 

 (as Matteucci was) by residual traces of a belief in 



97. Matteucci, C. Essai sur les Phenomenes electriques des 

 Animaux. Paris; Czirilian-Goeury and Dalmont, 1840. 



98. DU Bois-Revmond, Emil (18 18-1896). Vorlaufiger Abriss, 

 einer Untersuchung iiber den elektromotorischen Fische. 

 Ann. Physik. Chem. 58: i, 1843. 



99. DU Bois-Revmond, E. Uniersuchungen iiber thierische Elek- 

 tricitdt. Berlin: Reimer, vol. I, 1848; vol. II, 1849. 



