As in biology, so in human history, a new form may result from the specialization of a long-existing, and hitherto very slowly changing, generalized or non-specialized form; as, for instance, occurs when a barbaric race from a variety of causes suddenly develops a more complex cultivation and civilization. This is what occurred, for instance, in Western Europe during the centuries of the Teutonic and, later, the Scandinavian ethnic overflows from the north. All the modern countries of Western Europe are descended from the states created by these northern invaders. When first created they would be called ‘new’ or ‘young’ states in the sense that part or all of the people composing them were descended from races that hitherto had not been civilized, and that therefore, for the first time, entered on the career of civilized communities. In the southern part of Western Europe the new states thus formed consisted in bulk of the inhabitants already in the land under the Roman Empire; and it was here that the new kingdoms first took shape. Through a reflex action their influence then extended back into the cold forests from which the invaders had come, and Germany and Scandinavia witnessed the rise of communities with essentially the same civilization as their southern neighbours; though in those communities, unlike the southern communities, there was no infusion of new blood, so that the new civilized nations which gradually developed were composed entirely of members of the same races which in the same regions had for ages lived the life of a slowly changing barbarism. The same was true of the Slavs and the slavonized Finns of Eastern Europe, when an infiltration of Scandinavian leaders from the north, and an infiltration of Byzantine culture from the south, joined to produce the changes which have gradually, out of the little Slav communities of the forest and the steppe, formed the mighty Russian Empire of to-day.