ELECTRIC FISH 



down at one gulp. They were everywhere, darting up 

 and down, from one side of the tank to the other, 

 stirring up the water in every direction. The little fish, 

 thus hunted down, tried to escape, but they were soon 

 caught by the electric discharge, killed or at least para- 

 lysed by it, and, turning belly upwards, gradually sank. 

 The eels swallowed them whole, then dashed after 

 others which met the same fate. This extraordinarily 

 sensational chase, in which the pursuer killed the prey 

 by electrical discharge, lasted for several minutes with- 

 out stopping. Then the eels, gorged and replete, 

 slackened their pursuit. They were growing weary and 

 their electric power was becoming exhausted. They 

 lay down on the bottom again to digest their food 

 in peace, their stomachs swollen out by the copious 

 meal. 



When the agitation was at its height, a strange 

 phenomenon might be observed. Now and again the 

 eels gave up their chase for a moment, stopped moving, 

 and sent out large bubbles of gas from their mouths, 

 which rose through the water and burst on the surface. 

 After this they began their chase again. These ex- 

 pulsions of gas took place several times during the 

 electric discharge. In the state of rest, on the other 

 hand, nothing of the sort took place, or it was only on 

 a very small scale. 



We find an explanation of these astonishing actions 

 when we compare them with a voltaic cell. The eel, 

 with its two interior batteries which produce electricity 

 under the voluntary action of the nervous system, 

 becomes an electrified body with a high potential. 

 This body, having two poles, situated at the two ex- 

 tremities, the electricity is irradiated all round them, 

 as in the well-known phenomenon of the magnetic 

 spectre; they can be shown in an identical graph. The 

 lines of force of the discharges radiate round the positive 

 pole, which is in front; some are lost, while others go to 

 rejoin the negative pole behind. This body, producing 



165 



