158 



PROCEEDINGS OF THE ACADEMY OF 



[1888. 



mining the resistance offered by muscle and nerve to a current of 

 electricity as in the case of the determination of the electro-motive 



force of the same, 

 the authors made 

 use however of the 

 round compensa- 

 tor Fig. 5 with 

 Christiani's modi- 

 fication, that is 

 with the addition 

 of the binding 

 screw O, a much 

 more reliable and 

 convenient instru- 

 ment than the 

 long rheocord. 

 The relations ex- 

 isting between the 

 resistance to be 

 determined or X 

 and that of the 

 resistance box R 

 and the portions 

 of the wire A S 

 S B on either side 

 of the wheel S 

 are, however, pre- 

 cisely the same as 

 Pj^ 5 in the case of the 



long rheocord since in both cases the ratio obtains of X : R : : A S 

 : S B as may be at once seen by a comparison of Figs. 5 and 1. 



In order that the amount of muscular and nervous tissue used in 

 the different experiments should be the same the authors made use 

 of the method employed by Hermann (1) of enclosing the tissue 

 between two plates (in the present instance of ebonite instead of 

 glass) to the four corners of one of which were cemented pegs so 

 that when the other plate rested on the latter a definite space was 

 included. It would have been desirable if practicable that the same 

 amount of nerve had been used as muscle but on account of the 

 scarcity of frogs, the season being winter and the great number of 



