ELECTRICAL BREAK-EXCITATION. 115 



negative pole overcomes the obstruction at the positive, and strong 

 current, at whose closure the excitation at the negative pole is. 

 entirely blocked by the obstruction at the positive 1 . 



When muscle- or nerve-currents exist, the direction of the exciting 

 current is not indifferent. In this case, closure of a current in the 

 same direction has far more effect than closure of one in an opposite 

 direction. 



It still remains to consider some objections which may be made, 

 and which have partly already been made, to these laws, and in 

 particular to the third. 



Hermann comes forward with the objection that he can see no 

 reason for thinking that of two events like in kind the coming into 

 existence and the disappearance of a current only the first should 

 produce an effect. 



But according to Hermann's own conception, the coming into 

 existence and the disappearance of a current, in so far as these act 

 as stimuli, are by no means events like in kind ; for it cannot be 

 assumed that the coming into existence of catelectrotonus is an 

 event like in kind to the disappearance of anelectrotonus. But 

 according to my conception, the coming into existence and dis- 

 appearance of a current are like events as regards the way in which 

 they act as stimuli. For with the disappearance of a current there 

 is always associated the coming into existence of a new current, 

 which causes the stimulus. Here there is in both cases a coming 

 into existence of catelectrotonus, so that the two events are clearly 

 absolutely alike in kind, which cannot be said of the other two. 

 For the movement of a body away from its position of equilibrium 

 is not to be assumed without some reason to be an event like in 

 kind to its movement into that position, even if both movements 

 are in the same direction. But according to my conception, only 

 movement away from the position of equilibrium the coming into 

 existence of catelectrotonus has an excitatory effect, not the 

 return to that position disappearance of anelectrotonus. 



I cannot at present call to mind any state the disappearance of 

 which acts as a stimulus on our organism ; though a large number 

 occur to me which do so at the moment of their coming into 

 existence and during their continuance. The electric current 



1 It is not necessary to consider the effects of exceedingly strong currents, which 

 Hermann (loc. cit. p. 103) has described under the title of the over-maximal phase 

 of the law of contraction ; for in this case, as Hermann has already said, there is only 

 an apparent contradiction of the acknowledged facts of the law of contraction. 



I 3 



