NATURAL SCIENCES OF PHILADELPHIA. 



107 



1888.] 



applied to the equator and transverse section of the muscle and nerve 

 respectively. The methods made use of by the authors in determin- 

 incr the electro-motive force of the gastrocnemius muscle and sciatic 

 nerve of the frog as given in the synopsis below is essentially that of 



Scheme of Determination of Electro-Motive Force with 

 Round Compensator. 

 L 



IVII Wire of round compensator. 



N Number of its divisions 1000. 



L Resistance offered by same. 



S Switcher. 



K Key. 



D Daniell Element. 



W Resistance oflered by D IVII B P' D and by IVII F P' D. 



P' Whippe. 



B Coils. 



F Coils. 



Y" Commutator. 



G Galvanometer. 



E Electrodes. 



M Muscle or Nerve. 



K Key. 



Ill Wheel. 



1 Fractional portion of wire of compensator. 



n Number of the division necessary to compensate. 

 PoggendorfF with the difference that the round compensator was 

 used instead of the long rheocord. This method^ consists essentially in 



1 Du Bois Reymond, op. cit. S 257. 

 Archiv fiir anat. u. Phys. 1885 S. 381. 



