']2 ANIMAL ELECTRICITY. LECTURE III. 



they are to be considered as algebraic sums of 

 kathodic and anodic effects respectively — resultant 

 from the predominance of one or other factor in 

 the series of alternating currents used to stimulate 

 the nerve. Further investigation will, perhaps, decide 

 this point. 



As regards the second question, I am very tired of 

 it indeed, for no one fails to put it to me, and I do not 

 know what the remarkable alteration of base-line 

 means. Sometimes I get away from the question by 

 saying that it means an alteration of the galvanometer 

 zero, which is a pretty obvious "answer." If that 

 does not answer, I have to apologise for the remarkable 

 alteration, and to say that it has only been by reason of 

 this uncompromising method of recording that it has 

 been made so prominent, and that in ordinary galvano- 

 metric observations one does not attend to it. But 

 that does not get me out of trouble, and I am told 

 it ought to be attended to, that the rise or fall, as the 

 case may be, are very significant. Yes, they are 

 significant, but I don't know what they are significant 

 of. I am quite aware of the fact that carbonic acid 

 from without always drives the zero up at first, while 

 carbonic acid from within (by tetanisation) always 

 drives the zero^ downwards, but I do not know what 

 that means. 



^ By zero, I mean the position of rest of the permanently 

 deflected magnet, not its position of rest when no current is 

 passing. 



