“As an example of what could be sought with advantage, let us suppose that we take a number, sufficient for statistical purposes, of persons occupying different social classes, those who are the least efficient in physical, intellectual, and moral grounds forming our lowest class, and those who are the most efficient forming our highest class. The question to be solved relates to the hereditary permanence of the several classes. What proportion of each class is descended from parents who belong to the same class, and what proportion is descended from parents who belong to each of the other classes? Do those persons who have honourably succeeded in life, and who are presumably, on the whole, the most valuable portion of our human stock, contribute on the aggregate their fair share of posterity to the next generation? If not, do they contribute more or less than their fair share, and in what degree? In other words, is the evolution of man in each particular country favourably or injuriously affected by its special form of civilisation? “Enough is already known to make it certain that the productiveness of both the extreme classes, the best and the worst, falls short of the average of the nation as a whole. Therefore, the most prolific class necessarily lies between the two extremes, but at what intermediate point does it lie? Taken altogether, on any reasonable principle, are the natural gifts of the most prolific class, bodily, intellectual, and moral, above or below the line of national mediocrity? If above that line, then the existing conditions are favourable to the improvement of the race. If they are below that line, they must work towards its degradation.” The main body of the book deals with enquiries in special cases--the judges of England between 1660 and 1865, statesmen, commanders, authors, men of science, poets, musicians, painters, divines, senior classics of Cambridge, oarsmen and wrestlers. The concluding chapters should be printed in gold. Only one or two notes can here be made. Mr. Galton believes that the dark ages were largely due to the celibacy enjoined by religious orders on their votaries:--