< 

 534 LIVING TORPEDOS IN BERLIN. 



Malapterurus, that I first recognised the irreciprocal conduction, 

 and traces of it are not wanting in Dr. Sachs' experiments on the 

 Gymnotus. In these animals also, the impenetrability of the 

 organ to heterodromous currents will tell in the same way in 

 strengthening its action on external points. This will however 

 be of special service to the Torpedo, for this fish is at a dis- 

 advantage, as compared with electrical fresh-water fishes, in con- 

 sequence of sea water being so good a conductor. 



I have on former occasions brought under notice, in electrical 

 fishes, surprising instances of that organic adaptedness, which is 

 ever a new source of wonder even to the strict adherent of 

 mechanical causality. I showed how the construction of the 

 electrical organ of the Torpedo on the one hand, of the Gymnotus 

 and the Malapterurus on the other, is adapted to the different 

 conducting power of sea and fresh water J ; how with their growth, 

 the organs of the Gymnotus and of the Torpedo change precisely 

 in the way in which fresh and sea water demand 2 ; how also 

 the electromotive forces of both fish, according to all measurement, 

 are in the same ratio to each other as the resistances of fresh and 

 sea water 3 ; how the circumstance that the organ is positively 

 polarised by shocks of extremely short duration, tends to strengthen 

 the shock, and how in consequence of the negative polarisability of 

 the organ when tetanised, it is brought about that a fresh discharge 

 starts again almost from zero 4 . I showed also the indispensable 

 immunity of electrical fishes and their progeny in regard to 

 electrical shocks. Finally, the remarkable mode of terminal 

 branching, described by Wagner in the organ of the Torpedo, 

 seems to be adapted to ensure the simultaneous coming into action 

 of all electrical plates, innervated by the same primitive-nerve 

 fibres 5 . But in one point only we failed to understand the arrange- 

 ment of the Torpedo organ : it seemed to us, that the region which 

 is above the back of the animal, in the neighbourhood of the 

 sagittal plane, was, to borrow an expression from fortification, a 

 dead angle, although it is precisely most in need of protection 

 (434, 435). Now this drawback is undoubtedly to a certain 

 extent remedied by irreciprocal conduction. 



Gesammelte Abhandlungen, vol. ii. p. 696. 



Untersuchungen, &c., p. 14 f. ; Archiv fur Physiologic, 1883, p. 253. 



Untersuchungen, &c., p. 41 1 f. 



Untersuchungen, &c., p. 220. 



Untersuchungen, &c., p. 293. 



