PHENOMENA OF MUSCLE AND NERVE. 323 



breaking excitation here lasts much longer than the polarisation 

 after-current. The breaking excitation cannot therefore be directly 

 dependent at any rate upon the establishment of this polarisation- 

 current. 



To this it may be objected that the long prevalence of an action- 

 current does not prove that a polarisation-current is not present, it 

 may be there all the time but overpowered. On the kathodal 

 side, however, we see how quickly, in all cases, the polari- 

 sation-current vanishes. Further, so long as the action-current 

 lasts, even though a portion of the polarising-current be present, 

 so long is the anodal region practically one where current enters, 

 not leaves, as the above theory requires. The break-excitation is 

 therefore dependent upon changes which the current has left in the 

 tissue upon the disappearance of positive polarisation, whether this 

 disappearance occur by a polarisation opposed current or by any 

 other process of removal of electrolytic products. A number of 

 objections to Griitzner's last publication may be reserved for a 

 later opportunity 1 . 



The extrapolar phenomena of muscle and nerve can be as com- 

 pletely explained as the intrapolar. The facts discovered by me 

 some time ago with the multiplier, namely 4- after-current in the 

 kathodal, stronger after-current in the anodal extrapolar region 

 of nerve, are now recognised as polarisation and action-currents 

 respectively 2 . By using a lighter and more aperiodic magnet we 



1 A few points only I must mention here. First, with regard to the experiments 

 made by me in 1875 upon the connection of the polarisation opposed current with 

 the breaking contraction, and now first communicated. These experiments, as I can 

 show most accurately from the records, were made with leading-in contacts at a 

 great distance from the cross-section. Happily the positions of the electrodes were 

 marked and fixed on the myograph papers which have the muscle tracings. In the 

 second place, the conclusion which I draw from these experiments is not of recent 

 date, but was arrived at eight years ago, the whole experiment being, indeed, conducted 

 with this in view. I am able, by documents, to prove this to any who may 

 be interested in the matter. Its present publication is due to the fact that an investi- 

 gation into the nature of nerve-excitation, reaching back to the year 1871, and for 

 which I have collected a mass of experimental material, has only recently appeared 

 to me sufficiently advanced to permit of its publication ; some part has already 

 appeared in this ' Archiv.' In the third place, Grutzner has cited a discrepancy of 

 Tigerstedt's as in disagreement with my law of the polarisation increment. I have 

 already shown in another place the insufficiency of the discrepancy a fact which 

 Grutzner cannot have known (Hofmann and Schwalbe's ' Jahresbericht,' 1882, ii. p. 19.) 



2 Following out a suggestion made by Pfliiger, I assigned this latter explanation, 

 eleven years ago, to the phenomena of the catelectrotonic region, as I then erroneously 

 believed that the extrapolar polarisation currents in nerve must be in character, 

 being led to this by my experiments with the schema having an envelope of thick 

 fluid (see Pfluger, 'Archiv,' vol; vi. p. 357). 



Y 2 



