PHENOMENA OF MUSCLE AND NERVE. 325 



to the polarising 1 current (see previous remarks) which tends 

 rapidly to decrease. In consequence of this the kathodal current 

 must first become stronger and then tend to decrease. The 

 phenomena, during closure of the polarising-current, are there- 

 fore no less in accordance with the principles laid down than are 

 those following its break. 



6. Concluding Remarks. 



The foregoing investigation has accomplished the task of ex- 

 plaining the phenomena of intrapolar after-currents as given by 

 du Bois-Reymond ; it has also introduced new facts ; and further, it 

 has widened our knowledge of the extrapolar after-currents, has 

 extended these to muscle, and fully explained them. 



There remain unnoticed, (with the omission of facts connected 

 with electrical organs, in regard to which I could make no 

 investigation, and of the after-currents which, at any rate, allow 

 of explanation by means of our principles), certain statements of 

 du Bois-Reymond as to the way in which ' positive polarisation ' is 

 favoured by the use of currents, the direction of which coincides 

 with the natural direction of the excitatory wave ; upon these 

 phenomena the author lays very great w r eight (for muscle, see du 

 Bois-Reymond, Sect. 10 ; for nerve, Sect. 17). 



In respect to nerve, du Bois-Reymond's own statements are 

 dubious, but in respect to muscle they are pretty decisive, although, 

 strangely enough, the most conclusive method of experiment has 

 not been employed, viz. that of leading through the entire muscle 

 and leading-off the after-currents from two intrapolar regions in 

 the two muscle-halves at the same time. But, before acquiescing 

 in the far-reaching conclusions which du Bois-Reymond draws from 

 these phenomena, it might be well to inquire what share the above 

 enunciated simple laws, which have entirely escaped du Bois-Rey- 

 mond's notice, may have in the production of the phenomena. I 

 prefer, however, to leave this inquiry to du Bois-Reymond himself, 

 merely hinting here at conditions which would suffice at once to 

 explain the whole of this wonderful thing. 



Du Bois-Reymond had, at the extremities of both muscles, fibres 

 of which the ends were for the most part injured, as his intimations 

 with regard to the currents of rest show. This circumstance which 



