PHENOMENA OF MUSCLE. 251 



the anodic spot of the muscle. Accordingly contraction can only 

 be supposed to commence simultaneously throughout the whole 

 intrapolar tract when the currents are of greater density in the 

 muscle than the strongest currents used by Biedermann. 



Had not du Bois-Reymond adhered to the old view of simul- 

 taneous stimulation in the whole intrapolar tract, had he even 

 regarded as an open question that of the starting-point of excita- 

 tion in direct electrical stimulation, he would scarcely have em- 

 ployed in his experiments on polarisation muscles divided by 

 tendinous intersections. At the same time it was an unfortunate 

 circumstance that the very muscles which he chose on account of 

 certain advantages presented by them should have been traversed 

 by tendinous intersections, for had those intersections not been 

 present, du Bois-Reymond would certainly have recognised the 

 error of his assumption, at all events in those experiments in which 

 he led off the polarisation-current from one or the other half of 

 the intrapolar tract. 



In a future communication I shall have to speak of du Bois- 

 Reymond' s researches on secondary electromotive phenomena 

 in nerve. 



