ELECTRICAL FISHES 457 



of current. This notwithstanding, du Bois-Eeymond refers the 

 difference of current-intensity in the homodromous and hetero- 

 dromous directions, not to inequality of E.M.F. in either case, 

 since the relative and absolute positive after-current follows on 

 the homodromous polarising current, but to a real irreciprocity, 

 i.e. to unequal resistance in the two directions, the organ con- 

 ducting better in the direction of the discharge than in the other. 

 It is evident that such a mode of conduction, " which is thus 

 far without any counterpart," can hardly be accepted without 

 stringent justification. When all attempts at deciding the point 

 showed only that, " contrary to all appearance, it is not necessary 

 to invoke irreciprocal resistance to explain the facts," du Bois- 

 Eeymond finally believed that he had found such justification in 

 his determinations of the resistance to conductivity in the elec- 

 trical organ (Torpedo}. He compared the resistance in prisms 

 of the electrical organ of uniform length and diameter, of 

 frog's muscle (parallel with the fibres), and of salt solution (sea 

 water). "With this object the different bodies were enclosed in 

 glass tubes of uniform dimensions, and traversed longitudinally 

 by current. The resistance of the circuit, which included a 

 galvanometer as well as the tubes, was measured by the 

 reciprocal magnitude of the galvanometer deflections, as caused 

 by the opening current of a sliding inductorium. He found that 

 an organ -preparation drawn through the glass tube was a far 

 worse conductor, even with homodromous passage of current in 

 the long directions of the prisms, than frog's muscle parallel 

 with the fibres, or salt water, under the same conditions. 



Du Bois-Eeymond thence concluded that if the ascendency 

 of homodromous currents depended upon positive polarisation 

 -i.e. an additional E.M.F., amounting even to 40 Groves the 

 organ -preparation would, in comparison with muscle, or with 

 physiological salt solution, conduct better, and its resistance would 

 therefore " seem to be enormously increased," when it loses 

 positive polarisability, along with its vital properties. Neither con- 

 sequence, however, occurs in du Bois-Eeyrnond's experiments, but 

 rather the contrary. Without referring to this fact, which it is 

 hard to judge without personal investigation, Gotch, with whom 

 Schonlein is now in full agreement, endeavoured by direct experi- 

 ment to disprove the theory of irreciprocal conduction. He em- 

 ployed apparatus modelled on the " spring myograph," in which the 



