234 RESEARCHES ON SECONDARY ELECTROMOTIVE 



defined, and that from the electromotive changes taking- place in 

 this region set up by the stimulating current no polarisation-current 

 could flow into the galvanometer electrodes, yet the far more 

 important polarisation occurring at the tendinous intersections 

 would not be excluded. 



For between the two galvanometer electrodes lies the tendinous 

 septum, which severs the two muscles in such a way that each 

 consists of two separate muscles lying one behind the other. In 

 front of the intersection the current leaves the fibres of one of 

 the separate muscles, and behind it, enters the fibres of the second 

 separate muscle. On one side, therefore, of the intersection lie 

 innumerable kathodic spots, on the other side as many anodic 

 spots, and the former as well as the latter are the seat of polar 

 changes. The change at the anodic spots gives rise to a polarisation- 

 current, and that at the kathodic spots gives rise to a second such 

 current. As was shown in the first communication, both currents, 

 according to circumstances, flow sometimes in the same direction, 

 sometimes in an opposite direction to the stimulating current. 

 The polarisation-current entering the galvanometer-circuit, re- 

 presents the sum, or the difference, in short, the algebraic sum 

 of both currents, which would appear separate if either the whole 

 of the anodic spots or the whole of the kathodic spots could be 

 suddenly rendered inert at the tendinous intersection. 



Hence du Bois-Reymond's researches prove nothing with regard 

 to an * internal polarisation,' that is to say, with regard to the fact 

 that the stimulating current polarises the contractile substance 

 in the proper intrapolar tract, where it runs within the contractile 

 substance of all the fibres. 



The polarisation-currents described by du Bois-Reymond were 

 for the most part the result of polarisation taking place at the 

 tendinous intersection, or the algebraic sums of the two polarisation- 

 currents produced there. 



Besides this, polarisations in the neighbourhood of the upper, 

 and still more in that of the lower electrode, became more con- 

 siderable the nearer the galvanometer electrodes were to the 

 stimulating electrodes. Hence du Bois-Reymond observed the 

 algebraic sum of four synchronous polarisation-currents. 



Another special disadvantage in the experiments of du Bois- 

 Reymond consists in the fact that the tendinous intersection of each 

 of the muscles used by him runs in a very oblique direction to the 

 axis of the muscle, and that the intersections of the two muscles 



