Humboldt gives a very interesting narrative of the mode of the capture
of the gymnoti employed by the Indians of South America. This is done by
rousing the eels by driving horses and mules into the ponds which those
fish inhabit, and harpooning them when they have exhausted their
electricity upon the unhappy quadrupeds.
"I wished," says Humboldt, "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 eye-balls 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, swimming 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 strength 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 had a tragic termination, and expected to see most of
the quadrupeds killed; but the Indians assured me that 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 appeared 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; 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
receiving any shock so long as the cord was dry. All the circumstances
narrated by Humboldt establish the close analogy between the gymnotus
and torpedo in the vital phenomenon attending the exercise of their
extraordinary means of offence. The exercise is voluntary and exhaustive
of the nervous energy; and, like voluntary muscular effort, it needs
repose and nourishment to produce a fresh accumulation.
------------------