CHAP. IX. MUSOULAE AND NEEVOUS TISSUES. 97 



that he has obtained indications of an increase in the 

 nerve current, by passing an electric current along 

 a portion of the same nerve. He says, " If any part 

 of a nerve is submitted to the action of a permanent 

 current, the nerve, in its whole extent, suddenly 

 undergoes a material change in its internal con- 

 stitution, which disappears on breaking the circuit 

 as suddenly as it came on. This change, which is 

 called the electro-tonic state, is evidenced by a new 

 electro-motive power, which every point of the whole 

 length of the nerve acquires during the passage of 

 the current, so as to produce, in addition to the 

 nerve current, a current in the direction of the 

 extrinsic current. As regards this new mode of 

 action, the nerve may be compared to a voltaic pile, 

 and the transverse section loses its essential import. 

 Hence the electric effects of the nerve, when in the 

 electro-tonic state, may also be observed in nerves 

 without previously dividing them.'' 



The experiment was repeated in the following 

 manner : — Platinum wires, connected with the gal- 

 vanometer, were placed in contact with the two 

 portions of the nerve, (the longitudinal and the trans- 

 verse sections,) so as to obtain the nerve current. 

 The current from one, three, or six of Grove's 

 middling-sized cells was then passed along another 

 portion of the nerve, at different distances from that 

 portion connected with the galvanometer, the elec- 

 trodes of the battery being pointed. When the 

 current from the battery was confined to a small 



