CHAP. IX.] ANIMAL ELECTRICITY AND LUMINOUSNESS. 245 



the organ which causes the development or discharge of electricity, 

 but no traces of an electrical current can be detected in the nerves 

 themselves. If the nerves of an electrical organ be cut, irritation of 

 those segments of them which adhere to the organ will excite dis- 

 charges, just as the irritation of muscular nerves under similar 

 circumstances will cause contractions ; or direct irritation of por- 

 tions of the organ itself will produce discharges (Matteucci) . Any 

 general excitation of the nervous system will cause discharges; 

 thus strychnine, while it throws the muscular system into spasms, 

 provokes frequent and violent discharges of the electrical organs. 



From these observations, it seems impossible to adopt any other 

 conclusion than that the electrical organ is the generator of the elec- 

 tricity; or, at least, that it may collect and accumulate the electri- 

 city generated all over the body in the ordinary nutritive processes. 

 This latter opinion, however, is rendered unlikely from the imper- 

 fect conducting power of animal substances, unless further research 

 should develop some channels by which electricity generated at a 

 distance might be conveyed to the electrical organ. Whatever view 

 of the case be adopted, it is difficult to discover in the facts above 

 stated respecting the electrical fishes any support to the electrical 

 theory of nervous power. On the contrary, the very existence of a 

 peculiar organ for the specific purpose of generating electricity 

 would appear adverse to such a doctrine. Were the nervous cen- 

 tres the source of electricity, surely an arrangement of a less com- 

 plex character, and deviating to a less extent from the natural 

 structure of other fishes of the same genus, would have sufficed for 

 the manifestation of the peculiar power of the electrical fishes. 



Some insects (the glow-worm for instance), and other creatures, 

 possess the faculty of generating light. The power resides in a 

 particular organ, and is regulated by the nervous system. It is 

 strikingly analogous to that by which electricity is developed. 

 Yet no one would assign the nervous system as the source of the 

 luminous emission. Nor are we justified in affirming from the one 

 instance that the nervous power is electricity, any more than we 

 should, from the other, be authorized in asserting that the nervous 

 power is light. 



On the subjects discussed in this chapter, reference is made to Miiller's 

 Physiology by Baly ; Daniell's Chemistry ; the articles "Animal Electricity" 

 and " Animal Luminousness," in the Cyclop. Anat. et Physiol. ; Matteucci, 

 Traito des Phenoinenes -Electrophysiologiques des Auimaux. 



