— 109 — 



during generations while the muscular fibres were being slowly 

 transformed into electrical elements, the developing organ was of 

 some real use to the species, it is impossible to account for its 

 appearance by the direct influence of natural selection. It might 

 be supposed that the muscular fibres during the process of trans- 

 formation retained their ordinary function, until their greatly 

 overgrown motor plates were able to discharge shocks sufficiently 

 powerfull to tell in the struggle for existence, and that, this 

 stage, being reached, natural selection stepped in and, while neg- 

 lecting the muscular fibres, carefully attended to the further ela- 

 boration of their motor (electric) plates. But even if it were shown 

 that a given number of muscular fibres retained their power of 

 contracting until their combined overgrown motor plates were 

 able to discharge serviceable shocks, no explanation of the increa- 

 se in size of the motor plates would be given. 



„It is doubtless possible that electric organs are intimately re- 

 lated to some other structures, that correlation of growth may 

 account for their presence. Taking into consideration the comple- 

 city of electrical organs, and especially their richness in nerve 

 tissue, I am inclined to think that it will be found as difficult 

 to discover the structure or structures that served as a foster- 

 brother to the electric batteries, as it has been to discover their 

 independent origin. I am unable to think of any structures in any 

 of the electrical fishes which, as they developed, could induce 

 muscular fibres in various parts of the body to transform them- 

 selves into electric batteries. 4 



Mit Betrübniss wendet Ewart seine Blicke zu den Physiologen und 

 erwartet von denselben eine Lösung der Frage über die Umwand- 

 lung der Muskelfasern in die elektrischen Elemente, ebenso wie 

 die Physiologen ihrerseits die Lösung von den Morphologen er- 

 warten. 



Ganz ähnlicher Meinung ist Romanes auch '). 



„Nun aber, schreibt er, wenn wir so zu Gunsten der natürlichen 

 Zuchtwahl von der Korrelation absehen und daher, um wenigstens 

 überhaupt eine Hypothese zu haben, einfach annehmen, das be- 

 treffende Organ in seinem jetzigen Zustande müsse für den Piochen 

 von irgend welchem Nutzen sein, haben wir ja immer noch die 

 Frage zu beantworten: was können dem Thiere wohl jene An- 

 fangsstufen seiner Ausbildung genützt haben, als die Muskelfasern 



') Darwin und Dach Darwin. Ueb. v. Vetter. Bd. I. 1892. S. 430. 



