122 ANIxMAL ELECTRICIT\'. LECTURE V. 



variation. Equal extrapolar currents. Anodic and 

 Kathodic, physiological as judged by the tests of 

 crushing and of hot water, not physiological as judged 

 by the test of anaesthetic vapours. In short a 

 thoroughly unsatisfactory position of matters ; from 

 which, althouo'h I see no issue at this moment, an 

 issue must be found. All that I feel entitled to say 

 at this perplexed stage is that you will at least realise 

 how it has happened that my experiments on nerves 

 that answered by "yes" and "no" have been many, 

 while on nerves that give no clear answer at all my 

 experiments have been few. And perhaps at this 

 juncture the negative results afforded by mammalian 

 nerve may serve to throw into clearer relief the 

 positive results obtained on frog's nerve. 



REFERENCES. 



(i) Electrotonic currents discovered and named by du Bois- 

 Reymond in 1843 (" Thierische Elektricitat," vol. ii., p. 

 289) ; explained as being polarisation effects by Hermann 

 (" Pfluger's Archiv," v., p. 264 ; vi., p. 312 ; vii., p. 301 ; 

 1872-3; Summary in " Hermann's Handbuch," vol. ii., 

 P- 174). 



(2) ''Positive polarisation'' first mentioned by du Bois- 

 Reymond in the '* Thierische Electricitiit," vol. i., p. 240. 

 and more fully described in the " Berliner Sitzungs- 



