361 



from the electric organs ; yet the strata of watef 

 transmitted no shock, while Mr. Bonpland irri- 

 tated the animal strongly by an immediate con- 

 tact, and received some very violent shocks, 

 If I had plunged the most delicate electroscopes 

 we know, prepared frogs, into contiguous strata 

 of water, they would no doubt have felt contrac- 

 tions at the moment when the gymnotus seemed 

 to direct it's stroke elsewhere. Prepared frogs., 

 placed immediately on the body of a torpedo, 

 experience, according to Galvani, a strong con- 

 traction at every discharge of the fish. 



The electrical organ of the gymnoti acts only 

 under the immediate influence of the brain and 

 the heart. On cutting a very vigorous fish 

 through the middle of the body, the fore part 

 alone gave me shocks. The shocks are equally 

 strong, in whatever part of the body the fish is 

 touched ; it is most disposed however, to dart 

 them forth, when the pectoral fin, the electrical 

 organ, the lips, the eyes, or the gills are pinched. 

 Sometimes the animal struggles violently with a 

 person holding it by the tail, without communi- 

 cating the least shock. Nor did I feel any when 

 I made a slight incision near the pectoral fin of 

 the fish, and galvanized the wound by the simple 

 contact of two pieces of zinc and silver. The 

 gymnotus bent itself convulsively, and raised 

 it's head out of the water, as if affrighted by a 

 sensation altogether new ; but I felt' no vibra- 



