504 



Mr. K. Lucas. 



[June 6, 



disturbance to the muscle.* Such facts as these suggest how dangerous it 

 is to argue from the failure of the muscular contraction to the absence of a 

 propagated disturbance in the nerve. The danger is especially great when, 

 as in the experiments of Herzen and Eadzikowski, we have to deal with 

 nerves under abnormal influences and likely therefore to transmit disturb- 

 ances abnormal either in their time-relations or in their magnitude. Until 

 we have some index of the presence and absence of the nervous impulse 

 more reliable than its success in passing the junctional region and provoking 

 the muscle to contraction, we cannot accept as proved the occurrence of an 

 electric response in nerve unaccompanied by a nervous impulse. 



We must turn, therefore, to the evidence brought in favour of the converse 

 proposition, that the propagated disturbance may be present with no electrical 

 accompaniment. I fear that the experiments of Ellison, which I have 

 mentioned, give us very little help in this matter, at least in the present state 

 of the enquiry. Dittler and Satakef have repeated them within the present 

 year and fail to confirm the results which Ellison obtained. They find in fact 

 that cinchonamine hydrochloride, like other drugs which suspend the activities 

 of nerve, abolishes simultaneously the nervous impulse and its electrical 

 accompaniment. If one can still be detected so can the other, and as soon as 

 one fails the other shows no trace. They have suggested that Ellison's results 

 rest chiefly on his failure to realise that in a nerve whose conduction process is 

 abnormal the propagated disturbance undergoes a decrement which increases 

 with the length of nerve traversed. Neglecting this factor, he may have so 

 chosen the seat of excitation that the propagated disturbance set up was able 

 to reach the muscle without complete extinction, but failed to cover the longer 

 distance which separated it from the electrodes connected to the galvanometer. 

 The question can hardly yet be thought of as settled, but this much is clear, 

 that without more exact confirmation Ellison's work cannot be taken as 

 evidence that there can be a propagated disturbance unaccompanied by an 

 electric response. 



There remain then the experiments of Gotch and Burch. Boruttauj repeated 

 those experiments which related to the absence of a second electrical response 

 in a cooled region of nerve and its appearance in a warmer region beyond. 

 He could not satisfy himself that there was ever complete absence of the 

 second electric response in one region unless it was also absent in the other. 

 Gotch,§ after analysis of the photographic records on which he and Burch had 



* Adrian and Keith Lucas, 'Journ. Physiol.,' 1912, vol. 44, p. 90. 

 t Dittler and Satake, ' Arch. f. d. ges. Physiol.,' 1912, vol. 144, p. 229. 

 | Boruttau, 'Arch. f. d. ges. Physiol.,' 1901, vol. 84, p. 402. 

 § Gotch, ' Journ. Physiol.,' 1902, vol. 28, p. 52. 



