THE multiplication of horses in America, since their introduction by the Spanish conquerors, has been prodigious. Innumerable herds, each consisting of many thousand animals, roam over the plains of both continents, from Patagonia to the south-western prairies of North America; and, notwithstanding the warfare waged on them by man, by whom they are slaughtered for their hides alone, their numbers would increase to a pernicious excess, were it not for the destruction caused among them by floods and droughts. The supply of water often fails in the sultry plains, and then the horses, tortured to madness, rush into the first marsh or pool they can find, trampling each other to death. Rivers have been rendered quite impassable by the stench of thousands that had plunged into them to slake their thirst, and had been drowned, being too much exhausted to crawl up the muddy banks. The beds of many streams in the Pampas are paved with a breccia of bones thus deposited. The periodical swellings of the rivers are no less fatal to them. The mares may be seen, during the season of high water, swimming about followed by their colts, and feeding on the tall grass, of which the tops alone wave above the waters. Thus they lead for some time an amphibious life, surrounded by alligators, water serpents, and other carnivorous reptiles, the marks of whose teeth are often printed on their thighs. The impetuous rush of a herd of wild horses impelled either by some panic or by raging thirst, is called a _stampedo_: one of them is, thus described in Murray’s Travels in North-America:—