300 ELECTKICAL ORGANS IN FISHES. 



Keymond on the electro-motor phenomena of muscle and 

 nerve, prove that in these structures currents take place, the 

 result of nutritive process as well as of functional action ; 

 and the observations of Mr. Baxter (Phil. Trans. 1848-52, 

 Proceedings of Royal Soc. 1855) have determined the existence 

 of electrical currents manifested during secretion and respi- 

 ration. There can be no doubt whatever, that in every living 

 organism more or less numerous and powerful electric dis- 

 turbances are produced by its organic processes ; and that its 

 general electric equilibrium is provided for by the resulting 

 currents in the organism itself, and in the medium in which 

 it lives. The problem which the physiologist has to solve, in 

 attempting to explain the mode of action of the electrical 

 apparatus in the fish, may be therefore thus briefly stated : 

 What are the anatomical conditions, and the vital actions 

 (meaning by vital all the actions of whatever kind, performed 

 by the living structure), essential to the production of a 

 sensible current of electricity, such as is produced by the 

 apparatus in question ? 



Here it becomes necessary to review the more important 

 successive opinions which have been taken of the electric 

 property of the apparatus. Walsh (Phil. Trans. 1773) con- 

 cluded that the electricity of the Torpedo resides in the 

 electric organs ; that their upper and under surfaces are 

 capable, from a state of electric equilibrium, of being instantly 

 thrown, "by a mere energy, into a plus and minus state, like 

 that of a charged phial ; and that the current results from a 

 conducting medium between their opposite surfaces being sup- 

 plied, naturally, by the medium in which the animal lives, or 

 artificially. The dependence of the electro-motor energy of the 

 apparatus on the nervous centre has been more distinctly stated 

 by Matteucci (Biblioth. Univ. xii.) and Dr. John Davy (Phil. 

 Trans. 1834), the batteries being therefore viewed as analo- 

 gous to Ley den jars, or an inductive apparatus. Eudolphi (loc. 



