LIVING TOEPED08 IN BEKLIN. 453 



at the first glance incredible that so large an electromotive force 

 should prevail in our preparations of organs, and another cause must 

 be sought for the different strength of the two currents. 



A difference of current strength must depend upon one of two 

 causes either upon unequal electromotive strength or upon unequal 

 resistance. It is conceivable that in the electrical organ an irre- 

 ciprocal resistance may exist 1 , i.e. that it may conduct better in 

 the direction of the shock than in the other. Electrolytes conduct 

 only in so far as they are decomposed ; according to a well- 

 established law, however, electrolysis is preceded by a similar 

 arrangement of electropositive and negative elements, which 

 arrangement we have taken as the basis of our explanation of the 

 shock and of positive polarisation. If this arrangement occurred 

 more easily in the absolutely positive direction or in this direction 

 exclusively, it would be comprehensible why the organ should 

 conduct the homodromous better than the heterodromous current. 

 The dependence of the hypothetical irreciprocal resistance on the 

 vital condition might be explained on the ground that the in- 

 equality of the resistance in the two directions was an expression of 

 electrical properties of the organ molecules which depended on their 

 life. Thus we see ourselves in face of a problem which often recurs 

 in galvanism and generally remains unsolved, namely to dis- 

 criminate whether an observed difference of current strength arises 

 from a difference of electromotive force or of resistance. 



In the present case one method of answering this question would 

 consist in introducing into the primary circuit so considerable a 

 resistance in addition to that of the preparation of the organ, that 

 the latter should disappear. If then the difference between the 

 two currents disappeared while that of the two polarisations 

 remained, this difference would be proved to be due to difference of 

 resistance. I planned an experiment of this kind, in which, besides 

 the preparation, I introduced as resistance a tube bent twice at 

 right angles, 7 1 centims. long and two millims. internal diameter, 

 containing physiological (normal) salt solution. The ends of the 

 tube were closed with clay and dipped into two vessels of zinc 

 solution. The difference of current strength in the two directions 

 disappeared, but unfortunately owing to the diminished functional 

 activity of the preparation, that of the polarisation current was also 

 absent. In this case nothing more could be done as to the 



1 Comp. Arthur Christiani, Beitrage zur Elektricitatslehre. Ueber irreciproke 

 Leitung elektrischer Strbme, Berlin, 1876. 



