220 



OF Mrsri.F.s AND M:I;YF.S. 



ic expeeted iii experiments of this nature ; and it 

 may In- uueoiidit ionally inferred fromtlii< c. >rrespond- 

 ence that i icgat Lve variation and excitement in thener\es 

 are two intimately connected and inseparable processes, 

 r rather t \vo a>peets of the same process observed by 

 dit't'erent means. 1 



5. The negative variation of the nerve current is 

 not the only electric change known to occur .in nerves. 

 l'nder the name ' Elect rot onus ' we have already (ch. 

 viii. 1, p. 125) mentioned certain changes in the ex- 

 citability which occur in the nerve fibre as soon as an 



n 



ci 



n 



V\<;. 60. Tnii CIIAN<.I.S IN 



nri;iN(; I.I.KI i \;< IM -. 



electric current is transmit led through a part of it. 

 These changes in the excitability corropond with 

 changes in the electric condition of ner\es, \\hich \\ e 

 called electrotonic. In tig. <><>, " n" represents a nerve, 

 a and /, two wires applied to the ner\c through \\hich an 

 elect ri" current is transmitted from *' toward fc; " i- 

 Iherefore the aipule, /, the kathode of the current em- 

 ])loved for the generation nf , Ird rolonns. As soon as 

 this current i- closed, "// ///' i>inl <>/ tin' //- //, on I In' 

 x't,lt> uf tin- <iiin,/, ( from / bo a) became more positive^ 

 a// ,,,i ihr *i'l<- i >f /In- hiilxi.lr (from /,- to // ) more 



' gee N 1 Aildili.uis, N". 1L'. 



