But it is not the jaguar and the alligator alone which lie in wait for the South American horse, for even among the fishes he has a dangerous enemy. The rivers and marshes of the Llanos are often filled with electrical eels, which send forth at will from the under part of the tail a stunning shock. These eels are from five to six feet long. They are able, when in full vigour, to kill the largest animals, when they suddenly unload their electrical organs in a favourable direction. Humboldt having accidentally set his foot on a gymnote which had just been taken out of the water felt the whole day severe pains in the knees and almost in every joint. Lizards, turtles, and frogs seek the morasses where they are safe from their discharges, and all other fishes, aware of their power, fly at the sight of the formidable gymnotes. They stun even the angler on the high river-bank, the moist line serving as a conductor for the electric fluid. The capture of these eels affords a highly entertaining and animated scene. Mules and horses are driven into the pond which the Indians surround, until the unwonted noise and splashing of the waters rouse the fishes to an attack. Gliding along, they creep under the belly of the horses, many of whom die from the shock of their strokes; while others, with mane erect, and dilated nostrils, endeavour to flee from the electric storm which they have roused. But the Indians, armed with long poles, drive them back again into the pool. Gradually the unequal contest subsides. Like spent thunderclouds, the exhausted fishes disperse, for they require a long rest and plentiful food to repair the loss of their galvanic powers. Their shocks grow weaker and weaker. Terrified by the noise of the horses, they timidly approach the banks, when, wounded with harpoons, they are dragged on shore with dry and nonconducting pieces of wood; and thus the strange combat ends. The Llanos are never more beautiful than at the end of the rainy season, before the sun has absorbed the moisture of the soil. Then every plant is robed with the freshest green; an agreeable breeze, cooled by the evaporating waters, undulates over the sea of grasses, and at night a host of stars shines mildly upon the fragrant savannah, or the silvery moonbeam trembles on its surface. Where on the margin of the primitive forest, girt with colossal cactuses and agaves, groups of the mauritia rise majestically over the plain, the stateliest park ever planted by man must yield in beauty to the charming picture of these natural gardens, bordered here by impenetrable thickets, and there by the blue mountain-chain, behind which the fancy paints scenes of still more enchanting loveliness.