ELECTRICAL BREAK-EXCITATION, 111 



hence that on closing- and opening- a current the same nerve is not 

 acted on with different current-strengths, but different nerves are 

 acted on at closure and opening,, which, I believe, may often enough 

 happen. For if the break- stimulation of a current is really nothing 

 else than the make-stimulation of its polarisation-current, it is 

 conceivable that in the above experiment on man the battery- 

 current, which enters the body at one electrode and leaves it at the 

 other, may flow along paths different from those of the polarisation- 

 current, whose circuit must be completed through the tissues alone 

 and which may therefore stimulate other nerves. 



This experiment brings us to a new fact, which, though it is 

 connected with experiments previously noticed (p. 108), must be 

 separately considered here. As already mentioned, neuro-electric, 

 additive break-contractions appear earlier at break of the main than 

 of the nerve-circuit. The nerve-current which acts here as stimulus 

 meets with less resistance in its passage along the derivation- 

 circuit than in the substance of the nerve. What is true of the 

 nerve-current is true also of the current of internal polarisation. 

 It is therefore easy to show that if unpolarisable electrodes are 

 applied to a nerve at indifferent points, i.e. where there is no 

 nerve-current, break-contractions appear earlier if the current is 

 broken in the main circuit than if in the nerve-circuit. This 

 will be evident if cases I are compared with the corresponding- 

 cases 3 in the experiments at page 109. In each series, i. e., the 

 length of wire required to elicit the first break-contraction is 

 greater in case i than in case 3 ; thus 300 is greater than 275, 

 and so on. In case i the current was made and broken in the 

 nerve-circuit, in case 3 in the main circuit. 



Hermann made similar experiments four years ago, but did not 

 publish them until shortly after the publication of my preliminary 

 communication and of Tigerstedt's complete paper. He also con- 

 cludes from his experiments, the results of which, interesting to us, 

 he thus summarises, that ' where the break-contraction is struggling 

 for existence it appears if there is any difference at all with weaker 

 currents and is stronger if the current is .broken in the main 

 circuit than if in the nepve-circuit.' Hence he concludes that the 

 counter-current due to polarisation is concerned in the production 

 of the break-contraction. In my opinion Hermann was not justified 

 in drawing this conclusion from the above-mentioned experiments, 

 for the reason that though his experiments were made a long time 

 ago, he has only now drawn the conclusion from them, or at least 



