388 OBSERVATIONS AND EXPERIMENTS 



not stronger than that of a vigorous fish 1 . An opening- shock 

 with the coil quite pushed in and one Grove in the circuit, taken 

 directly through the handles, has about the same strength as such 

 a shock. 



6. Of the direction of the shock in the Malapterurus. 



The simplest observation teaches that, in accordance with Bil- 

 harz' prediction, the motion of electricity in the organ of the 

 Malapterurus occurs in the direction of its length. But the further 

 surmise, inferred by Bilharz from Pacini's rule, that the current 

 in the organ of this fish would flow from the tail to the head, 

 &s in that of the Gymnotus (see above, p. 371), has not been 

 confirmed. 



The very first experiment which I made on the I3th August, 

 1857, with the fish brought with him by Prof. Goodsir, and which 

 I communicated 2 to the Academy on the same day, was the reverse 

 of what Bilharz had inferred from the microscopical appearances, 

 with what seemed to be such complete justification. It has since 

 then been established in numerous experiments, that the shock in 

 the organ of the Malapterurus is invariably directed from the head 

 towards the tail. Just as a column of the organ of Torpedo would 

 have to bend forwards with its upper end in order to become a 

 column of the organ of Gymnotus, so it would have to bend back- 

 wards with the same end in order to become one of the organ of 

 Malapterurus. 



The hope of finding a constant relation between the nerve-ending 

 and the distribution of tension in the electrical plates seemed thus 

 shut out. But a remarkable way out of this difficulty presented 

 itself. Ecker had observed shortly before in the pseudo-electrical 

 organs of certain species of Mormyrus (M. dorsalis and anguilloides), 

 that the nerve-tubes do not pass directly into the surfaces of the 

 pseudo-electrical plates turned towards them, but go into the plates 

 as though through sharply punched holes ; they then swell knob-like, 



1 Comp. a corresponding experiment on the Gymnotus, Ges. Abh. xxx. 4. 



2 Monatsberichte, etc., 1857, p. 424. As early as 1855, * ne Florentine surgeon, 

 Ranzi, who died shortly afterwards, and who had resided in- Egypt for the sake of 

 his health, had determined the direction of the discharge of the Malapterurus by 

 irreproachable experiments, using silver spoons as electrodes. I was unacquainted 

 with these experiments, because they were only printed in the two first volumes 

 of the Nuovo Cimento, which were not to be had either in Berlin or Gb'ttingen until 

 much later, so that I was obliged to obtain a copy of the essay from Italy (Comp. 

 Archiv fur Anatomie, etc., 1859, p. 209). 



