CATFISH AND EELS. 185 



base of the anal fin. The fasciculi are divided by longitudi- 

 nal partitions into hexagonal prisms, and transverse divisions 

 separate these into small cells. The cells are filled with 

 a gelatinous matter, and the whole apparatus is abundantly 

 supplied with nerves from the spinal marrow. In the Tor- 

 pedo, these nerves come directly from the brain. 



" The amount of electricity furnished by the Gymnotus is 

 enormous. Faraday made a calculation in regard to a speci- 

 men of ordinary size examined by him, that a single medium 

 discharge was equal to that from a battery of 3500 square 

 inches charged to its maximum. It need not then be a 

 matter of surprise that the Gymnotus is capable of killing a 

 horse by repeated discharges ; which it does by applying its 

 whole length along the belly of the animal when .in the 

 water. The method of capturing the Gymnotus made use of 

 by the South American Indians, consists in driving a number 

 of horses and other cattle into the muddy pools in which the 

 Electric Eels abound. Eoused from their retreats in the mud, 

 the Gymnoti emerge into the water, and gliding in among 

 the animals, give to them violent shocks. A succession of 

 discharges results in weakening the Eels to such a degree, as 

 to make it a matter of little danger or difficulty to capture 

 them. The voltaic pile, formed by the electric apparatus of 

 the Gymnotus, is much like that of the Torpedo ; the column 

 being longitudinal, however, in the natural position of the 

 animal, instead of vertical. The anterior or cephalic extrem- 

 ity is positive ; the caudal negative ; and the animal is 

 capable of discharging any portion of its column. The sub- 

 stance occupying the cells is a dense albuminous liquid, with 

 a small amount of common salt. Each cell is separate and 

 independent, answering to the cell of the galvanic battery. 



