232 KESEAKCHES ON SECONDAEY ELECTROMOTIVE 



of the polarising- current were brought into contact with the muscle 

 from the inner (femoral) side ; between these, on the outer side, the 

 electrodes were placed to lead off the polarisation- current. On 

 account of the high resistance of the tendons, which would become 

 heated and dried, it is impossible to lead the current to the muscle 

 by means of ordinary pads applied to the fragments of bone out- 

 side the ivory plates ; a method which otherwise would have 

 had great advantages.' With reference to the last point, I may 

 mention that du Bois-Reymond used up to as many as 50 Groves. 

 I at first never went beyond 8 Daniells, for I only wished to 

 stimulate the muscle, not seriously to injure it at the same time. 



In order to understand the results of du Bois-Reymond's re- 

 searches, it will next be necessary to indicate how the anodic and 

 kathodic spots are distributed in the muscle. 



The current from the stimulating anode as it enters the natural 

 longitude of the muscle near its tendon cannot, as a rule, enter the 

 contractile substance through the natural transverse section of the 

 individual muscle-fibres ; it must rather in its course from fibres in 

 the neighbourhood of the electrode to fibres at a greater distance 

 from it, pass through the first-named transversely or obliquely. 

 Hence, the lines of current radiating from the electrode become 

 parallel to the muscle-fibres only at some distance from their source. 

 Every fibre through which a portion of current flows in a trans- 

 verse direction has both anodic and kathodic spots. Moreover, 

 as the double muscle taken- as a whole tapers off at the upper and 

 lower ends, a considerable number of its fibres terminate at varying- 

 distances from the commencement of the proper tendons. In the 

 case of the semimembranosus there is in addition the circum- 

 stance above mentioned, that it has considerable accessions of fibres 

 in the direction from below upwards. 



If the current entered and left through the tendons, the whole 

 tract of muscle in which fibres take origin or in which they 

 terminate would have a corresponding number of anodic or 

 kathodic spots, and one portion of the muscle would present an 

 anodic tract, the other a kathodic, understanding thereby the tracts 

 of muscle in which the anodic and kathodic spots are respectively 

 aggregated. If the stimulating electrodes are applied to the longi- 

 tudinal surface of the muscle but near the tendons, and yet in 

 the tapering part of the muscle, the current would meet numerous 

 muscle-fibres in its course, and would enter or leave them through 

 their natural ends. More especially would this be the case, as 



