The real difficulty is not, as with the animals, to explain how man could have reached America, but from what quarter he actually has reached it. In surveying the whole extent of the New World, it was found to contain two great families, one in the lowest stage of civilization, composed of hunters, and another nearly as far advanced in refinement as the semi-civilized empires of Asia. The more polished races were probably unacquainted with the existence of each other on the different continents of America, and had as little intercourse with the barbarian tribes by whom they were surrounded. Yet they had some things in common both with these last and with one another, which remarkably distinguished them from the inhabitants of the Old World. They had a common complexion and physical organization,--at least, bearing a more uniform character than is found among the nations of any other quarter of the globe. They had some usages and institutions in common, and spoke languages of similar construction, curiously distinguished from those in the Eastern hemisphere. Whence did the refinement of these more polished races come? Was it only a higher development of the same Indian character which we see, in the more northern latitudes, defying every attempt at permanent civilization? Was it engrafted on a race of higher order in the scale originally, but self-instructed, working its way upward by its own powers? Was it, in short, an indigenous civilization? or was it borrowed in some degree from the nations in the Eastern World? If indigenous, how are we to explain the singular coincidence with the East in institutions and opinions? If Oriental, how shall we account for the great dissimilarity in language, and for the ignorance of some of the most simple and useful arts, which, once known, it would seem scarcely possible should have been forgotten? This is the riddle of the Sphinx, which no Œdipus has yet had the ingenuity to solve. It is, however, a question of deep interest to every curious and intelligent observer of his species. And it has accordingly occupied the thoughts of men, from the first discovery of the country to the present time; when the extraordinary monuments brought to light in Central America have given a new impulse to inquiry, by suggesting the probability--the possibility, rather--that surer evidences than any hitherto known might be afforded for establishing the fact of a positive communication with the other hemisphere.