PHENOMENA OF MUSCLE. 237 



There is always a similar condition when a current enters a muscle 

 composed entirely of parallel fibres, not at its natural end but at the 

 side, even if the current meet with no fresh fibres on its way. The 

 current enters those fibres which are in the immediate neighbour- 

 hood of the stimulating- anode with greater density than those 

 which are more remote. It is further to be noted that only a 

 portion of the current which enters a particular fibre flows on into 

 it, the rest passing on to fibres more remote from the stimulating 

 anode. It is therefore first necessary to know exactly the laws of 

 transverse polarisation, in order to be able to say to what extent 

 in this case kathodic polarisation can take place along with anodic. 

 In any case, there is a preponderance of anodic polarisation (as 

 would be supposed theoretically, and as can be practically demon- 

 strated), and I have therefore considered it alone in the above 

 pages. Sufficient has been said to show how difficult or impos- 

 sible it is to unravel the intricacies of the different individual 

 polarisations which must have existed in du Bois-Reymond's ex- 

 periments. 



One other result on which du Bois-Reymond seems to lay great 

 weight remains to be considered. In a special series of experiments 

 he brought one galvanometer electrode to the equator of the pair of 

 muscles, whilst the other was placed either immediately above the 

 lower or below the upper stimulating electrode. The stimulating 

 electrodes, if I understand rightly, were placed near the ends of the 

 muscle. Thus the polarisation-current was led off either entirely 

 from the upper or entirely from the lower half of the muscle. It 

 now resulted that the upper half showed stronger positive polarisa- 

 tion when the current was ascending than when it was descending, 

 whereas the lower half gave stronger positive polarisation when the 

 stimulating current flowed from above downwards. 



Let us for the moment imagine that the upper and lower 

 halves of the pair of muscles were strictly symmetrical, both 

 tendinous intersections passing exactly through the equator, that 

 the stimulating electrodes were arranged symmetrically, and, finally, 

 that one electrode lay on the equator, the other alternately on 

 symmetrical spots of the upper or of the lower half of the muscle. 

 In this case any one who knows that polarisation phenomena 

 depend not on internal polarisation but on changes occurring at the 

 points where the current enters and leaves the muscle, would readily 

 see that the upper half must necessarily be in the same relation to 

 the ascending current in every respect as the lower half is to the 



