552 SUPPLEMENT ON 



negroes, and certain aborigines of the country in which it is 

 found, enjoy the privilege of touching it without feeling the 

 influence of its action. We are ignorant whether this ex- 

 eruption proceeds from compressing the animal strongly by 

 the back, as some persons affirm, or from interposing between 

 the hands and the body of the fish, some substance which is 

 a non-conductor of electricity, or by employing some other 

 trick, which it is their interest to pass off as a supernatural 

 faculty ; but it is stated positively, that women afflicted 

 with nervous fevers, have been able to handle it without 

 any inconvenience. Henry Collins Flagg has seen a woman 

 affected with one of those maladies, interrupt a chain which 

 was prepared for the passage of the electric current from the 

 animal. 



The shocks produced by the gymnotus are accompanied 

 with sparks altogether similar to those produced in electrical 

 operations. They were seen for the first time, in London, by 

 Walsh, Pringle, and Magellan. The first of these observers 

 found it sufficient to obtain them, to compose a part of the 

 chain with two plates of metal isolated on a square of glass, 

 and sufficientlv near each other to leave between them but a 

 very small interval The light was then easily distinguished 

 when the experiment was made in a chamber into which 

 day-light could not penetrate. Several other experiments 

 have also proved the identity of this fluid of the gymnotus 

 with electricity. 



Above the natatory bladder, which in this fish extends to 

 the interior of the tail, and is lengthened almost from the 

 head to the extremity of the body, is found an apparatus 

 astonishing both for its bulk and its structure, and which 

 it is impossible not to recognize as the electric organ. The 

 gymnotus has four of these organs, two large, and two small, 

 extending on each side of the body from the abdomen to the 

 end of the tail, the first above and the second below, and 



