148 NEBVE CTJfiEENT CHAP. XI. 



I have already had occasion to relate some experi- 

 ments in chap. ix. in which I endeavoured to obtain 

 an increase of the nerve ciuTcnt according to the 

 mode suggested by Dtj Bois Eetmond, but entirely 

 failed in doing so. As they were not undertaken 

 for the express purpose of ascertaining whether the 

 nerve current is affected during nerve action, the 

 following were performed. 



Is the nerve current affected during nerve action? 

 Instead of employing a nerve separated from the 

 animal, the experiments were conducted in a manner 

 similar to those that have been already related in 

 the previous part of the present chapter, viz. with 

 the sciatic nerve. The electrodes of platinum were 

 coated at one extremity with shell-lac, leaving, how- 

 ever, the extreme end bare, and one of them was 

 pointed so as to be easily inserted into the sub- 

 stance of the nerve, whilst the other electrode 

 presented a flat surface to rest upon the surface 

 of the nerve. The distance at which 4he electrodes 

 were placed from each other varied from an inch to 

 a quarter of an inch, but were generally within about 

 half an inch of each other. When the needle indi- 

 cated the existence of the nerve current, the upper end 

 of the sciatic nerve was stimulated either by means of 

 the glass pen, or copper wire, or an electric current, 

 to produce muscular contraction in the leg : some- 

 times the nerve was stimulated by a constant current, 

 at other times by an intermitting current. The 

 current was passed at one time as a direct cm'rent, at 



