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under the influence of nervous action and discharged immediately 

 that action ceases, somewhat like soft iron under the influence of an 

 electric current. Such, however, is not the real state of the case. 

 The electric organ is always charged. It maybe conclusively shown 

 by experiment that the action of that organ never ceases, and that 

 round the body of a Torpedo, and probably of every other electric 

 fish, there is a continual circulation of electricity in the liquid me- 

 dium in which the animal is immersed. In fact, when the electric 

 organ, or even a fragment of it, is removed from the living fish and 

 placed between the ends of a galvanometer, the needle remains de- 

 flected at a constant angle for twenty or thirty hours, or even longer. 



" I must here explain that in electro-physiological experiments it 

 is highly advantageous to employ, as extremities of the galvanometer, 

 plates of amalgamated zinc immersed in a neutral saturated solution 

 of sulphate of zinc. This arrangement, which can be worked with 

 the greatest facility, gives a perfectly homogeneous circuit, leaving 

 the needle at zero in an instrument of 24,000 coils ; the liquid in 

 contact with the animal part experimented on has the greatest pos- 

 sible conductibility while it does not act chemically on the tissue, 

 and the apparatus is entirely free from secondary polarity. 



" To return to the Torpedo. The electric organ, or a portion of 

 it, detached from the fish and kept at the temperature of freezing, 

 preserves its electromotive properties for four, six, or even eight 

 days ; and an organ which has been kept for twenty-four hours in a 

 vessel surrounded with a frigorific mixture of ice and salt, is found to 

 possess an electromotive power as great as that of the organ recently 

 detached from the living fish. Thus the electric organ retains its 

 functional activity long after both muscular and nervous excitability 

 have been extinguished. 



" What then is the action of the nerves on this apparatus ? Here 

 again experiment affords a very distinct and conclusive answer. De- 

 tach the organ of a live torpedo and cut it into two equal portions, in 

 such a way as to leave each half in connexion with one of the large 

 nervous trunks ; place the two halves on a plate of gutta percha, 

 with electric couples opposed ; that is, with the similar surfaces (say 

 the dorsal) in contact ; and connect the two free (ventral) surfaces 

 with the extremities of the galvanometer. There will usually be no 

 deflection of the needle, or, at most, a very slight effect which will 



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