I06 ANIMAL ELECTRICITY.-- LECTURE V. 



" physIcaP electrotonus " of German monogTaphs, not 

 suppressed by anaesthetics, which we shall designate 

 by the colourless and non-committal expression "resi- 

 dual deflection." 



This residual deflection — particularly well marked 

 in tig. 46 — ^itself gradually declines in course of time, 

 mainly I think, by reason of the drying, and therefore 

 increasing resistance, that you recollect to be one of 

 the effects produced by anai^sthetics. But this is a 

 detail upon which we need not dwell, and in this 

 connection it is hardly necessary to insist upon the 

 obvious fact that in this case, as in that of the neoa- 



o 



tive variation, chloroform exercises a permanent effect 

 and ether a temporary effect. 



There are other signs by which we can recognise 

 that the extrapolar currents, An. and Kat., although 



^ How much sometimes turns upon a word ! Hering, and 

 his chief lieutenant, Biedermann, speak of " physiological" and 

 "physical" electrotonus, and by physical electrotonus I for a 

 long time supposed that they meant to designate a phenomenon 

 intermediate between the physiological effect proper to living 

 nerve and physical current-diffusion — an electrotonus in fact 

 proper to dead, but otherwise anatomically perfect nerve. And 

 in this [relief, although explicitly stating that in my hands 

 anaesthetics had served to distinguish between electrotonus and 

 current-escape, I nearly succeeded in persuading myself of the 

 existence of a physical electrotonus distinct from current-escape. 

 Hering, however, has since informed me that " physical electro- 

 tonus " arose as a laboratory term meaning neither more nor 

 less than current-escape. 



