22 



HANDBOOK OF PHYSIOLOGY ^ NEUROPHYSIOLOGY I 



FIG. 17. du Bois-Reymond and one of the schemata he postu- 

 lated for transmission at the end plate. 



'nerve force,' he brought clearer inductive rea.soning 

 to the interpretation of his obser\'ations. 



du Bois-Reymond confirmed Matteucci's demon- 

 stration that not only nerve-muscle preparations but 

 muscles themselves could produce electricity and, 

 with .soine acerbity, claimed priority for naming this 

 the 'muscular current' (Muskelstrom). Both Mat- 

 teucci and du Bois-Reymond distinguished muscular 

 current from the frog current' (la correnta propria 

 della rana), so named by Nobili to describe the current 

 flow between the feet of the prepared frog and any 

 other part of the animal. Neither Noijili (100) nor 

 Matteucci, nor even du Bois-Reymond at this time, 

 recognized that the so-called frog current was an 

 injury current consequent to their having trans- 

 sected their frogs. Nobili had thought it was a thermo- 

 electric effect due to differential cooling times of 

 nerve and muscle. 



du Bois-Reymond, using faradic stimulation, also 

 confirmed Matteucci's finding that the muscle current 

 was reduced during tetanic stimulation and named 

 this the negative variation. It is what is now called 

 the action current of muscle, du Bois-Reymond went 

 on to demonstrate the same negative variation in 

 nerve during activity and thus discovered the action 

 current of nerve which Matteucci had failed to find 

 with his less sensitive instruments, du Bois-Reymond 

 made the following claim, "If I do not greatly de- 

 ceive myself, I have succeeded in realizing in full ac- 

 tuality (albeit under a slightly different aspect) the 

 hundred years' dream of physicists and physiologists, 

 to wit, the identity of the nervous principle with 

 electricity." His great contemporary Carl Ludwig 

 (loi) was unwilling to accept this for, thinking still 

 in terms of the nerve as a telegraph wire, he held 



100. Nobili, L. Ann. chiin. el phys. 38: 225, 1828; 44: 60, 1830. 



(among other objections) that its resistance was too 

 great and its insulation too poor for it to be a good 

 conductor. 



Pfliiger (102) tried to o\ercomc some of these 

 difficulties by his 'liberation hypothesis.' In this he 

 stated that nervous transmission was "not a simple 

 advancing undulation in which the sum of the living 

 forces is not increased" but a situation in which "new 

 tension forces are set free by the living forces of the 

 stimulus and become in turn living forces with each 

 onward step." In spite of the obscurity of the termi- 

 nology (this is Morgan's translation), one can detect a 

 foreshadowing of the ideas held by today's physi- 

 ologists. 



du Bois-Reymond elaborated a theory that all un- 

 damaged muscle had a resting potential between the 

 middle (positive) and the tendons (negative) and 

 that during activity this decreased, thus giving the 

 'negative variation.' He was still not clear on the 

 role of injury currents for he thought injury merely 

 intensified the resting potentials. On this point he 

 entered into acrimonious dispute with his pupil Her- 

 mann who was equally stubborn in insisting that 

 there were no resting potentials in the absence of in- 

 jury and that all current flow in muscle and nerve 

 was due to damage (103). Hermann therefore intro- 

 duced the term 'demarcation currents' to describe 

 them. Later experimentation has shown both men to 

 have been partially right and partially wrong. 



du Bois-Reymond's conception of regularly oriented 

 'electromotive particles' arranged along the surface 

 of muscle and of nerve was the forerunner of the 

 schemata of polarization that were to be developed 

 more fully and more accurately by his pupil Berns- 

 stein (104) and that lie at the core of modern theory. 

 The critical issue as to whether the negative variation 

 in nerve potential was identical with the excitatory 

 process (i.e. the nerve impulse) was taken up by 

 Bernstein who set out, at du Bois-Reymond's sugges- 

 tion, to compare their velocities, von Helmholtz, one 

 of the same brilliant group schooled in Miiller's 

 famous laboratory, had in a triumph over primitive 

 apparatus succeeded in measuring the velocity of 



101. Ludwig, C.-^rl (1816-1895). Uber die Ki-afte der Ner- 

 venprimitivenrohr. Wien. med. Wchnschr. 46: 47, 1861. 



102. Pfluger, E. (1829-1910). Vnter suchungen iiber die Physi- 

 ologie des Eleclrolonus. Berlin: Hirschwald, 1859. 



103. Hermann, Ludim.\r (i 838-1 91 4). W'eitere Untcrsungen 

 iiber die Ursache der electro-motorischen Erscheinungen 

 an Muskeln und Nerven. Arch. ges. Physiol. 3:15, 1870. 



104. Bernstein, Julius (1839-1 9 17). Untersuchungen iiber den 

 Erregungsvorgang im Nerien- und Muskelsysleme. Heidelberg : 

 Winter, 1871. 



