6. The seven hundred and fifty years that follow are in the highest degree interesting and important; for they record the achievements of the early manhood of humanity, as represented by the nations that were most advanced in civilization, or contributed to the general progress of the world. Men developed their inherent capacities far more during that period than in all the previous centuries, however numerous they may have been. It was followed by about five hundred years of gradual decline, and that by a thousand years of confusion caused by the corruption of the old society and the imperfection of its elements, together with the irruption of vast hordes of barbarians, who brought in fresh and vigorous, but untamed blood, with rude and fierce manners. They were gradually tamed by fusion with the cultured races, and out of this union arose a civilization broader and more just, toward the perfection of which we ourselves are now rapidly advancing, and which, by its multiform vigor and unlimited resources, seems above the reach of decay. Its power of infusing new life into worn-out peoples and renewing the youth of nations as well as of civilizing barbarians appears irresistible. From this outlook we return to consider the steps by which Time has led us to such a desirable eminence. SECTION III. THE GRADUAL DEVELOPMENT OF INSTITUTIONS. 1. Man, at first, had no institutions. He existed in the simplest and most spontaneous way, finding shelter in caves and clefts of the rocks and beneath the primeval forests, groping his way by strong instincts which soon began to dawn into intelligence of the lowest and most material kind. How long he led a purely _animal_ life we have no means of knowing; but we may suppose that the necessities of self-preservation and his powerful social instincts very soon developed the germs of the family and of language. Childhood is comparatively long, and many generations must have passed before language could have acquired the distinctness and fixity that permitted it to come down through so long a period, and by so many different channels, to us. Yet there is plain evidence of an Eastern origin of all the various families of the race, and of a considerable mental development previous to the wanderings that peopled the East, the West, and the South. It has been remarked by Geologists that the introduction of any class of animal life was never made by its very _lowest_ orders, but usually by a class intermediate in organization between the highest and the lowest; some of the very lowest orders being represented in our own time.