Mr. Galton, in his work on "Hereditary Genius," has drawn attention in a striking chapter to the effect which the systematic destruction and expatriation, by the Inquisition or the religious intolerance of the government, of the leading men of the nation--its boldest thinkers, most ardent investigators, most prudent and careful and ingenious workers, in generation after generation--had in bringing about the moral and political decline of the three great Latin countries, France, Spain, and Italy--a decline of which, in the case of the two former at least, we have probably not seen the end. The persons killed or banished amounted only to a few thousands every year, but they were--no matter from what rank they came--the flower of the population: the men whose labor and whose influence enabled the State to keep its place in the march of civilization. The picture is very valuable (particularly just now, when there is so great a disposition to revel in the consciousness of vast numbers), as calling attention to the smallness of the area within which, after all, the sources of national greatness and progress are to be sought. The mind which keeps the mass in motion, which saves and glorifies it, would most probably, if we could lay bare the secret of national life, be found in the possession of a very small proportion of the people, though not in any class in particular-- neither among the rich nor the poor, the learned nor simple, capitalists nor laborers; but the abstraction of these few from the sum of national existence, though it would hardly be noticed in the census, would produce a fatal languor, were the nation not constantly receiving fresh blood from other countries.