512 LIVING TORPEDOS IN BERLIN. 



ness. In spite of the large amount of persistent polarisation, which 

 is in favour of the homodromous and opposed to the heterodromous 

 current, the additional resistance almost effaces the difference of the 

 two currents. Accordingly it seems proved that the irreciprocal 

 conduction rests upon resistance. Unfortunately, closer con- 

 sideration showed that this time also, the mode of viewing the 

 matter was not complete, and that it is impossible to decide between 

 polarisation and resistance by this manner of experiment. 

 We will call as before : 

 1 the strength of the homodromous, 

 /, that of the heterodromous current ; 



P the constant, which multiplied into the current density, 



measures the electromotive force of the homodromous ab- 



solutely and relatively positive polarisation for the unit length 



of the tract traversed ; 



FT the corresponding constant for the relatively negative polar- 



isation caused by both the currents ; 



R the resistance of the circuit containing the battery and the 

 galvanometer, exclusive of the resistance of the battery itself ; 

 n the small, 



N the large number of Groves ; 

 the electromotive force, 

 r the resistance of a single cell ; 

 W the additional resistance ; 

 a the specific resistance of the organ when it is traversed longi- 



tudinally in both directions ; 



I the length of the tract traversed, i. e. in this case of the pre- 

 paration itself, provided that the resistance of the skin is to 

 be included in R ; finally, 

 q its transverse section. 



Then, with the small number of Groves and without additional 

 resistance, we have 



nG-l.- (U-P) 



'- w 



nr 



