LIVING TOBPEDOS IN BERLIN. 445 



possible to excite effectually, in the manner above related, a single 

 column cut longitudinally. 



In such preparations the organ-current often gradually di- 

 minishes. Matteucci in Torpedos, and Robin in the Skate observed 

 it to rise somewhat after each shock, and something similar was 

 also seen by Sachs in his observations on Gymnotus *. In the few 

 experiments in which I succeeded in exciting bundles of columns by 

 mechanically exciting the nerves, the rapid subsidence of deflection 

 due to the shock blended itself in such a way with the effect of the 

 organ-current, that the shock deflection presented itself as a mere 

 transitory increase of the latter. But Sachs has further shown in 

 Gymnotus that tetanus of the organ weakens the current 2 . I had 

 no opportunity of making similar observations on the Torpedo. 



10. On the secondary Electromotive Actions of the Organ 

 of the Torpedo. 



I started upon this virgin soil with the greater zest because, as 

 the reader will remember, there seemed to be a contradiction 

 between the results of my experiments on this subject on Malapte- 

 rurus and those of Sachs on the Gymnotus. I longed to decide 

 which of these two antagonistic observations would accord with 

 those about to be made on the Torpedo. 



The apparatus and methods of experiment which I used were the 

 same that served for my recent researches on secondary electromotive 

 phenomena in muscle and nerve. The manner in which the 

 preparations of the organ were exposed to the polarising-currents, 

 and in which the secondary-currents were led off has been already 

 described. At the first glance it appears to be an advantage that 

 the organ preparations do not twitch like muscle. On the other 

 hand, as in nerve experiments, one is deprived of the evidence of 

 the continuance of functional activity which the twitch gives in 

 muscle. Although some of the difficulties which I anticipated did 

 not appear, yet the preparations made in the manner described could 

 not be compared in regularity with such naturally formed objects 

 of experiment as we possess in nerves and in certain muscles. 

 Whereas it is not difficult to provide for comparison a bit of sciatic 

 nerve or a muscle of equal size and freshness, and uninjured, it is 

 impossible to be assured of an equal number of uninjured columns 

 in our preparation. In the same fish the length varies between the 



1 Untersuchungen, pp. 170, 173. 2 Ibid. pp. 174, 187, 220. 



