114 ANIMAL ELECTRICITY. — LECTURE V. 



This is, in fact, the one obvious distinction between 

 an electrotonic current proper and a negative varia- 

 tion ; the latter is independent of the distance between 

 leading-in and leading-out electrodes. No doubt both 

 phenomena are an expression of polarisation, the 

 former of a stable polarisation, the latter of an un- 

 stable and fugitive polarisation that propagates itself 

 as a wave along the compound electrolyte^ ; but at the 

 present juncture it is not necessary that we should 

 study this rather complicated question, and I shall 

 reserve it for a future occasion. 



I wish rather to exhibit some further definite data 

 concerning the polarisation phenomena of nerve — data 

 of which I cannot at present propose any final ex- 

 planation, but which are evidently pieces of that 

 particular puzzle. 



One is a fact first pointed out by v. Fleischl, that 

 has figured in physiological literature for several years 

 past as a sterile item. The other is a little bunch of 

 facts that have tantalised me for the last ten years 

 by their paradoxical bearing. I have not hitherto 

 ventured to call attention to them, and I do so now 

 in a very dissatisfied frame of mind. They are frag- 

 ments, evidently significant, but I do not know what 

 they signify, I cannot even imagine what they signify. 



^ Boruttau has placed the finishing touch upon the identiti- 

 cation between the phenomena in nerve and in core-models by 

 showing that in the latter as in the former a diphasic negative 

 wave is aroused by a single induction shock whatever the 

 direction of the latter. 



