297' 



ccpted by these two kinds of laminae, are, 

 according to Cuvier, filled with a gelatinous 

 substance ; and the whole apparatus is abun- 

 dantly supplied with nerves. It is said to 

 possess power, when in full vigour, to knock 

 down a man, and benumb the limb affected, 

 in the most painful manner, for several 

 hours after communicating the shock ; and 



it is by this extraordinary faculty that the 

 Gymuotus supports its existence : the 

 fishes and. other animals 



Gymuotus supports its existence : the smaller 

 hich happen to 

 approach it being stupified, and thus falling 

 an easy prey to the electrical tyrant. Those 

 who wish to understand the nature of the 

 organs by which this electrical power is pro- 

 duced may find them minutely described by 

 Hunter in vol. 65. of the Philosophical 

 Transactions. The following observations 

 are given in Brande's Dictionary: "Al- 

 though to all outward appearance the Gym- 

 notus is nearly allied to the Eel, yet were 

 that part of the body cut off which contains 

 the nutrient, respiratory, and generative 

 organs, all the parts, in fact, which are 

 essential to the existence of the Gymnotus 

 as a mere fish, it would present a short 

 and thick-bodied form, very different from 

 that of the eel. The long electric organs are 

 tacked on, as it were, behind the true fish, 

 and thus give the Gymnotus its anguiliform 

 body. The back bone and muscles are of 

 course co-extended with the electric organs 

 | for their support and motion ; and the air- 

 | bladder is continued along the produced 

 ' electrophorous trunk, to give it convenient 

 specific levity. Two long dorsal nerves are 

 continued from the fifth and eighth cerebral 

 nerves for ordinary sensation and motion. 

 The spinal chord is continued along the 

 vertebral column, for the exclusive supply 

 of the electrical organs. These organs are 

 four in number ; two very large above, and 

 two small ones below. The electricity dis- 

 charged from them decomposes chemical 

 compounds, produces the spark, and mag- 

 netizes iron, as does that of the Torpedo. 

 But the magnetizing power seems to be re- 

 latively weaker, while the benumbing shock 

 communicated to other animals is stronger 

 than in any other electric fish." 



Ilumboldt has given a lively narrative of 

 the mode of capture of the Gymnoti, em- 

 ployed by the Indians of South America. 

 They rouse the Gymnoti by driving horses 

 and mules into the ponds which those fish 

 inhabit, and harpoon them when they have 

 exhausted their electricity upon the unhappy 

 quadrupeds. "I wished," says Ilumboldt, 

 "that a clever artist could have depicted 

 the most animated period of the attack : the 

 groups of Indians surrounding the pond, the 

 horses with their manes erect and eyeballs 

 wild with pain and fright, striving to escape 

 from the electric storm which they had 

 roused, and driven back by the shouts and 

 long whips of the excited Indians : the livid 

 yellow eels, like great water-snakes, swim- 

 ming near the surface and pursuing their 

 enemy : all these objects presented a most 

 picturesque and exciting 'ensemble.' In 

 less than five minutes two horses were killed : 

 the eel, being more than five feet in length, 

 glides beneath the body of the horse and 



discharges the whole length of its electric 

 organ : it attacks at the same time the heart, 

 the digestive viscera, and, above all, the 

 gastric plexus of nerves. I thought the 

 scene would have a tragic termination, and 

 expected to see most of the quadrupeds 

 killed ; but the Indians assured me the 

 fishing would soon be finished, and that only 

 the first attack of the Gymnoti was really 

 formidable. In fact, after the conflict had 

 lasted a quarter of an hour, the mules and ' 

 horses api eared less alarmed ; they no ; 

 longer erected their manes, and their eyes 

 expressed less pain and terror. One no 

 longer saw them struck down in the water ; 

 and the eels, instead of swimming to the 

 attack, retreated from their assailants and 

 approached the shore." The Indians now 

 began to use their missiles ; and by means 

 of the long cord attached to the harpoon, 

 jerked the fish out of the water without re- 

 ceiving any shock so long as the cord was 

 dry. All the circumstances narrated by the 

 celebrated philosopher, establish the close 

 analogy between the Gymnotus and Torpedo 

 in the vital phenomena attending the exer- 

 cise of their extraordinary means of offence. 

 The exercise is voluntary and exhaustive of 

 the nerrous energy ; like voluntary muscular 

 effort, it needs repose and nourishment to 

 produce a fresh accumulation. 



" I was so fortunate (says Professor Owen) 

 as to witness the experiments performed by 

 Professor Faraday on the large Gymnotus 

 which was so long preserved alive at the 

 Adelaide Gallery in London. That the 

 most powerful shocks were received when 

 one hand grasped the head and the other 

 hand the tail of the Gymnotus, I had pain- 

 ful experience ; especially at the wrists, the 

 elbow, and across the back. But our dis- 

 tinguished experimenter showed us that the 

 nearer the hands were together within 

 certain limits, the less powerful was the 

 shock. He demonstrated by the galvano- 

 meter that the direction of the electric cur- 

 rent was always from the anterior parts of 

 the animal to the posterior parts, and that 

 the person touching the fish with both hands 

 received only the discharge of the parts of 

 the organs included between the points of 

 contact. Needles were converted into mag- 

 nets : iodine was obtained by polar decom- 

 position of iodide of potassium ; and, avail- 

 ing himself of this test, Professor Faraday 

 showed that any given part of the organ is 

 negative to other parts before it, and positive 

 to such as are behind it. Finally, heat was 

 evolved, and the electric spark obtained." 



There are several other fish belonging to 

 the Gymnotus tribe ; but they are much 

 smaller ; and whether they possess any 

 electric power is a matter of great doubt : 

 yet the structure of the lower part of their 

 bodies seems to imply a similar contrivance 

 of nature. Most of them are natives of the 

 same climate as the Gymnotus Electricus, 

 and are considered edible food. The prin- 

 cipal are the Carapo Gymnote, the Rostrated 

 Gymnote, and the White Gymnote. 



GYMNURA. An insectivorous animal 

 belonging to the family Erinaceadae, inha- 



