In addition to the long continued selection exercised by severe climatic conditions and the consequent elimination of ineffectives, both of which affects a race, there is another force at work which concerns the individual as well. The energy developed in the north is not lost immediately when transferred to the softer conditions of existence in the Mediterranean and Indian countries. This energy endures for several generations and only dies away slowly as the northern blood becomes diluted and the impulse to strive fades. The contact of Hellene and Pelasgian caused the blossoming of the ancient civilization of Hellas, just as two thousand years later when the Nordic invaders of Italy had absorbed the science, art and literature of Rome, they produced that splendid century we call the Renaissance. The chief men of the Cinque Cento and the preceding century were of Nordic blood, largely Gothic and Lombard, which is recognized easily by a close inspection of busts or portraits in northern Italy. Dante, Raphael, Titian, Michael Angelo, Leonardo da Vinci were all of Nordic type, just as in classic times many of the chief men and of the upper classes were Nordic. Similar expansions of civilization and organization of empire followed the incursion of the Nordic Persians into the land of the round skulled Medes and the introduction of Sanskrit into India by the Nordic Sacæ who conquered that peninsula. These outbursts of progress due to the first contact and mixture of two contrasted races are, however, only transitory and pass with the last lingering trace of Nordic blood. In India the blood of these Aryan-speaking invaders has been absorbed by the dark Hindu and in the final event only their synthetic speech survives. The marvellous organization of the Roman state made use of the services of Nordic mercenaries and kept the Western Empire alive for three centuries after the ancient Roman stock had virtually ceased to exist. The date when the population of the Empire had become predominantly of Mediterranean and Oriental blood, due to the introduction of slaves from the east and the wastage of Italian blood in war, coincides with the establishment of the Empire under Augustus and the last Republican patriots represent the final protest of the old patrician Nordic strain. For the most part they refused to abdicate their right to rule in favor of manumitted slaves and imperial favorites and they fell in battle and sword in hand. The Romans died out but the slaves survived and their descendants form the great majority of the south Italians of to-day.