"Aristocracies do not last… Where, in France, are the descendants of the Frankish conquerors? The genealogies of the English nobility have been very exactly kept; and they show that very few families still remain to claim descent from the comrades of William the Conqueror. The rest have vanished... They decay not in numbers only. They decay also in quality, in the sense that they lose their vigor…The governing class is restored not only in numbers, but—and that is the more important thing—in quality, by families rising from the lower classes… If human aristocracies were like thorough-breds among animals, which reproduce themselves over long periods of time with approximately the same traits, the history of the human race would be something altogether different from the history we know."