xi ELECTRICAL FISHES 443 



VI. THE SUPPOSED " CUERENT OF REST " IN THE ELECTRICAL 



ORGAN 



The question of whether the electrical organ is normally 

 electromotive during rest, or in the state of excitation only, 

 is obviously of great significance to the theory of its mode 

 of action. This is another aspect of the same problem which 

 with reference to muscle formed the subject of the long 

 and animated controversy between du Bois-Reymond and 

 Hermann (supra), that ended finally in favour of the latter. If, 

 as has been determined, certain electrical organs are to be re- 

 garded as transformed muscles, adapted to a special function, it 

 would seem a priori very probable that the discharge of the 

 organ is no more than the " action current " of the " specialised 

 muscle," which would give as little external reaction in the resting 

 state as a true muscle. As a matter of fact, all previous investi- 

 gations have shown the " rest current " of the electrical organ, 

 when present, to be exceedingly feeble. Du Bois-Reymond him- 

 self found the organ of Malapterurus totally inactive during rest 

 (4 d, ii. pp. 672, 718). "It neither exhibited any similarity 

 with the muscle current, nor did it work, like a battery, in the 

 direction of a discharge." Eckhardt (I.e.) gives a precisely similar 

 reaction for the organ of Torpedo, in which Zantedeschi and 

 Matteucci had observed weak constant action in the direction 

 of the discharge. These effects, again, were comparatively 

 weak and insignificant. Eckhardt found all points of the dorsal 

 surface permanently positive to all points of the ventral surface, 

 and all points nearer the brain positive in the former, and 

 negative in the latter, to all more distant points. Matteucci 

 measured frogs' gastrocnemii against a bit of organ in the 

 multiplier circuit, proving one to be weaker, two, arranged like a 

 pile, stronger than the organ. He, moreover, observed that the 

 permanent P.D. between dorsal and ventral surface " is temporarily 

 removed after each discharge provoked in the preparation by 

 electrical or mechanical stimulation of the still attached nerve," 

 as could be demonstrated at a low temperature for days after- 

 wards. 



C. Sachs, one of whose chief distinctions it was (as du Bois- 

 Reymond said) to have tested the reaction of the resting organ in 

 Gymnotus, invariably observed on leading off' from the two polar 



