But, in order that the reader may have a better understanding of the subject, it will be well, before entering on it, to take a general survey of the political and social institutions of the races who occupied the land at the time of its discovery. The country of the ancient Mexicans, or Aztecs as they were called, formed but a very small part of the extensive territories comprehended in the modern republic of Mexico.[4] Its boundaries cannot be defined with certainty. They were much enlarged in the latter days of the empire, when they may be considered as reaching from about the eighteenth degree north, to the twenty-first, on the Atlantic; and from the fourteenth to the nineteenth, including a very narrow strip, on the Pacific.[5] In its greatest breadth, it could not exceed five degrees and a half, dwindling, as it approached its southeastern limits, to less than two. It covered, probably, less than sixteen thousand square leagues.[6] Yet such is the remarkable formation of this country, that, though not more than twice as large as New England, it presented every variety of climate, and was capable of yielding nearly every fruit, found between the equator and the Arctic circle. All along the Atlantic, the country is bordered by a broad tract, called the _tierra caliente_, or hot region, which has the usual high temperature of equinoctial lands. Parched and sandy plains are intermingled with others, of exuberant fertility, almost impervious from thickets of aromatic shrubs and wild flowers, in the midst of which tower up trees of that magnificent growth which is found only within the tropics. In this wilderness of sweets lurks the fatal _malaria_, engendered, probably, by the decomposition of rank vegetable substances in a hot and humid soil.[7] The season of the bilious fever,--_vómito_, as it is called,--which scourges these coasts, continues from the spring to the autumnal equinox, when it is checked by the cold winds that descend from Hudson’s Bay. These winds in the winter season frequently freshen into tempests, and sweeping down the Atlantic coast and the winding Gulf of Mexico, burst with the fury of a hurricane on its unprotected shores, and on the neighboring West India islands. Such are the mighty spells with which Nature has surrounded this land of enchantment, as if to guard the golden treasures locked up within its bosom. The genius and enterprise of man have proved more potent than her spells.