366 EFFECT OF IRRITATION OF A POLARIZED NERVE. 



in eitlier direction. For the intrapolar portion of the nerve the excita- 

 bility was increased for irritating currents traveling in the same direc- 

 tion as the ijolarizing current, and decreased for currents traveling in 

 the reverse direction, provided weak polarizing currents were employed. 

 But when these currents were stronger the excitability of the nerve was 

 decreased to irritating currents traveling in either direction. 



Schifif and Herzen * publish a number of characteristic experiments 

 which give results also widely differing from those obtained by Pfluger. 

 These authors observed that if the polarizing current excites the nerve, 

 after a lapse of time the opposite effect was obtained ; and, vice versa, 

 if the polarizing current '•'paretically" affected the nerve this could 

 after a time be replaced by an augmentation of the excitability. 



Notwithstanding so many of the best experimenters found it impossi- 

 ble to coufirm the results of Pfluger, these results are now formulated 

 in the books as laws. All other investigations are simply ignored and 

 those of Pfiiiger adopted, it may be, because no other investigator has 

 advanced a more beautiful theory which can be made to correspond to 

 what is known of the electro-motor properties of the nerves. Even 

 Wundtt was convinced of the truth of Pfliiger's theory, though it ap- 

 pears that the results which he obtained by no means correspond with 

 those of Piiiiger, for on i^a-ges 34 and 35 of his "Untersuchungen" he 

 speaks of an increased irritability between the anode and the muscle 

 where an ascending current was used, which, according to Pfliiger's 

 theory (it demanding a diminished irritability under these circum- 

 stances), is an impossibility. 



This was the state of the subject when early in September, 1876, Pro- 

 fessor Schift' drew my attention to it, since which time I have constantly 

 had it under consideration. The subject was so discouraging that I fre- 

 quently felt like giving it up in disgust, but, urged on by Professor 

 Schiff, I continued the study, and a definite explanation of the contra- 

 dictory facts was arrived at late in December, 1876. Up to that time I 

 had made almost two hundred successful experiments on the subject. 

 The results then arrived at were presented in a preliminary communica- 

 tion in the February (1877) number of the Archives de sciences ])hys. et 

 naturelles, as follows : " The difference in the effect of an irritation of a 

 polarized nerve, compared to that of a nonpolarized nerve, does not solely 

 depend on the circumstance that the portion irritated is to the side of the 

 anode or to the side of the Jcathode, but much more on the proportion ivhich 

 exists between the strengths of the irritating and polarizing currents.^'' 



This conclusion my later experiments haveabundantly confirmed, and 

 in this paper it is designed not only to expose the results of these later 

 exjieriments, but also to give in extenso the experiments which caused me 

 to come to the foregoing conclusion. It may be thought that this is a 



* Ueber die Veriiuder. der Erregljarkeit in dem durscli scliwacbe constante Strome 

 polaris. Nerven, Molescliott's Uutersuch., Bd. x, p. 432. 



tl must here express my thankfulness for the kind assistance of M. Darier in a 

 number of these exiieriments. 



