OF ELECTRICITY IN ANIMALS. 55 



t\vo points which receive this impulse. In the silurus it is 

 the same ; a much greater impression is made on us when 

 we touch different points of the animal at a greater distance 

 from each other. 



In fact, we may receive a discharge from a single surface 

 of the electric apparatus of the torpedo, by touching un sym- 

 metrical parts, that is to say, points where the number of 

 Ilie elements of the pile is not so great, because of the 

 different length of the prisms which compose it. Thus, 

 although the polarity may be identical on the same surface of 

 the apparatus, the fact of the inequality of electric tension 

 on the different points of this surface suffices to create the 

 possibility of a current, and to determine its direction. 



As to the origin of the electric force, we think that no one 

 can now see anything in it but the result of chemical actions 

 produced in the interior of the apparatus 



But be A ire they arrived at this opinion, physiologists ad- 

 vanced many hypotheses as the source of animal electricity. 

 Thus, when Du Bois llevmond had shown that the nervous 

 tissue possesses an electro-motive force sufficiently powerfid, 

 and that there exists in living nerves a current in a constant 

 direction, it was thought that the voluminous nerves which 

 belong to the electrical apparatus of fishes carry electricity 

 to it, as the blood-vessels supply blood to the organs. Mat- 

 ti'inti has demonstrated that a large lobe of the brain of the 

 torpedo is the origin of the nerves belonging to its electrical 

 apparatus. He lias observed that it is possible to remove all 

 the rest of the brain, without depriving the animal of the 

 power of giving voluntary or reflex discharges; but that it 

 can no longer do so when this lobe is destroyed. Ho has for 

 this reason named this the electric lobe of the torpedo. 



When a dying animal no longer gave spontaneous dis- 

 charges, it was sufficient, said Matteucci, to touch the electric 

 lobe in order to obtain discharges more violent than those 

 which the animal gave voluntarily during the state of perfect 

 activity. 



Nevertheless, the notion of Matteucci has been exaggerated, 

 when this thought was attributed to him, that electricity is 

 formed in the brain of the torpedo, and is conveyed by its 



