FISHES, 575 
them ; the eels, yellow and livid, looking like great aquatic serpents. 
swimming on the surface of the water, and chasing their enemies, 
were objects at once appalling and picturesque. In less than five 
minutes two horses were drowned. An eel, more than five feet long, 
glided under one horse, and discharged its apparatus through its 
whole extent, attacking -at once the heart, the viscera, and the solar 
plexus of the animal, probably benumbing and finally drowning it. 
When the struggle had endured a quarter of an hour, the mules 
and horses appeared less frightened, their manes become more erect, 
their eyes expressed less terror, the eels shunned in place of attacking 
them, at the same time approaching the bank, when they were easily 
taken by throwing little harpoons at them attached to long cords, the 
harpoon, sometimes hooking two at a time, being landed by means 
of the long cord. They were drawn ashore without being able to 
communicate any shock. 
Having landed the eels, they were transported to little pools dug 
in the soil, and filled with fresh water ; but such is the terror they 
inspire, that none of the people of the country would release them 
from the harpoon—a task which the travellers had to perform them- 
selves, thereby receiving the first shock, which was not slight, the 
most energetic surpassing in force that communicated by a Leyden 
jar completely charged. The Gymnotus surpasses in size and strength 
all the other electric fishes. Humboldt saw them five feet three 
inches long. They vary in colour, according to age, and the nature 
of the muddy water in which they live. Beneath, the head is of a 
fine yellow colour mixed with red ; the mouth is large, and furnished 
with small teeth arranged in many rows. 
The Gymnotus makes its shock felt in any part of its body which 
is touched, but the excitement is greater when touched under the 
belly and near the pectoral fin. The Gymnotus gives the most 
frightful shocks without the least muscular movement in the fins, in 
the head, or any other part of the body. The shock, indeed, depends 
upon the will of the animal, and in this respect differs from a Leyden 
jar, which is discharged by communicating with two opposite poles. 
It happens sometimes that a Gymnotus, seriously wounded, only gives 
avery weak shock, but if, thinking it exhausted, it is touched fearlessly 
and at once, its discharge is terrible. Indeed, the phenomenon de- 
pends so much upon the will of the animal, that, according to Von 
Humboldt, if it is touched by two metallic rods, the shock is com- 
municated sometimes by one, sometimes by the other wand, though 
their extremities are close together. 
The experiments already related in connection with the torpedo 
