. PHENOMENA OF THE GYMNOTUS. 205 



periment proves directly, that each of these vesicles forms 

 the elementary organ of the electric apparatus. I have 

 removed from a living torpedo a portion of one of its prisms, 

 about the size of the head of a large pin, and I placed it 

 in contact with the nerve of the galvanoscopic frog, and 

 frequently observed contractions produced in the frog, on 

 pricking the fragment of the prism with a piece of glass, 

 or any other pointed body. Now, if you consider that 

 each of the prisms is composed of a very large number of 

 vesicles or elementary organs, that Hunter counted 470 

 prisms in each organ of the torpedo, you will understand 

 that the discharge, being proportional to the number of 

 vesicles, must necessarily be very strong. 



The electric organ, then, is a true multiplying appa- 

 ratus. 



Volta supposed that it was a pile which the animal itself 

 rendered active by compressing its organ, and thus esta- 

 blishing the contacts between the latter and the skin. But 

 the experiments which we have described to you, in no 

 way confirm this hypothesis. It has been lately stated, 

 that the electric organ was analogous to the electro-mag- 

 netic coil, and that the discharge was a phenomenon of ex- 

 tra-current or of induction. 



If we assume, what microscopic observation proves that 

 in each vesicle there exists a nervous filament, which here 

 divides, it is difficult to discover the analogy between the 

 electric apparatus of the torpedo and an electro-dynamic 

 coil. 



Let us advance an hypothesis, which we shall hereafter 

 find to be supported by facts, or, at least, by powerful ana- 

 logies. 



Suppose, that every time the nervous irritation reaches 

 one of the elementary vesicles of the organ of the torpedo, 

 that the two electricities separate. Heat, which acts on 



