Now what are the changes of external circumstance which first, in the natural course of things, would bring an adverse influence to bear upon mankind? Here again we are on firm ground, because we know one great cause which has been always operating, and we know its natural and inevitable effects. This cause is simply the law of increase. It is the consequence of that law that population is always pressing upon the limits of subsistence. Hence the necessity of migrations, and the force which has propelled successive generations of men further and further, in ever-widening circles round the original centre or centres of their birth. Then, as it would always be the weaker tribes who would be driven from the ground which had become overstocked, and as the lands to which they went forth were less and less hospitable in climate and productions, the struggle for life would be always harder. And so it always happens in the natural and necessary course of things, that the races which were driven furthest would be the rudest--the most engrossed in the pursuits of mere animal existence. Is it not true that the lowest and rudest tribes in the population of the globe have been found at the furthest extremities of its great continents, and in the distant islands which would be the last refuge of the victims of violence and misfortune? “The New World” is the continent which presents the most uninterrupted stretch of habitable land from the highest northern to the lowest southern latitude. On the extreme north we have the Eskimo, or Inuit race, maintaining human life under conditions of extremest hardship, even amid the perpetual ice of the polar seas. And what a life it is! Watching at the blow-hole of a seal for many hours, in a temperature of 75° below freezing-point, is the constant work of the Inuit hunter. And when at last his prey is struck, it is his luxury to feast upon the raw blood and blubber. To civilized man it is hardly possible to conceive a life so wretched, and in many respects so brutal, as the life led by this race during the long lasting night of the Arctic winter. Not even the most extravagant theorist, as regards the plurality of human origins, can suppose that there was an Eskimo Adam--that any man was originally created or developed in the icy regions round the pole. Here then we have a case, beyond all question, of races driven by wars and migrations from the more temperate regions of the globe. So long as they were still in those regions, the ancestors of the Eskimo must have lived in another manner, and must have had wholly different habits. The rigors of the region they now inhabit have reduced this people to the condition in which we now see them, and whatever arts their fathers knew, suited to more genial climates, have been, and could not fail to be, utterly forgotten.