ELECTRIC FISH 



less important in them, and the electric power more so. 

 They are electrogenic muscles, and that is all. 



The vital process here exhibited deserves to be con- 

 sidered more closely. A circumstance so astonishing, 

 so different from what we see elsewhere, stands out and, 

 since we can the better appreciate it, it makes all the 

 rest more intelligible. In short, this process manifests 

 itself in two kinds of production, material substances 

 and energy. As regards material substances, some 

 remain and become part of the constitution of living 

 matter, others are expelled as excretions. The energy 

 has its origin in the chemical energy expended within 

 the material texture, and expresses itself in movement, 

 the formation of heat, and in electricity. These kinds of 

 vital movement, these manifestations of the energy put 

 forth by life in action are, in their own field, equivalent 

 in part to the substances excreted. They are thrown 

 out as excretions of energy; produced by the living 

 creature, they first serve its purposes and then their 

 surplus goes out to the environment and is there freed. 

 In Nature there are only differences of situation and 

 quantity; the fundamental quality remains the same 

 everywhere. 



If then, these electric organs, in spite of their strange- 

 ness, come within the scope of a general rule from which 

 they do not depart, their peculiar rarity gives them a 

 special quality of their own which, in its turn, merits 

 close examination. They exist only in fishes. Again, 

 they are found only occasionally and without any re- 

 lation to the affinities of groups. In every other detail 

 of their structure the eels are very far removed from the 

 torpedoes, and the electric catfish from the skate. 

 When these organs do exist, they are situated in different 

 parts of the organism. There is indeed a sort of 

 gradation in their capacity, which is moderate in the 

 skate and the mormyros, more considerable in the 

 torpedo, greater again in the electric catfish, and at 

 its greatest in the electric eel. To put them thus into 

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