good opportunity—each of the sort fitted to his capacities—as Charles Darwin had, the gain for human welfare would probably have been great; but if every boy then could have had as good inborn capacity for science, art, invention, the management of men—or whatever his strongest capacity was—as Charles Darwin had for science, the gain for welfare would certainly have been enormous.
The original differences in intellect, character, and skill which characterize men are related to the families and races whence the individuals spring. Each man's original mental constitution, which so largely determines how much more or less he will do for the world's good than the average man of his generation, is the product of no fortuity, but of the germs of his parents and the forces which modify the body into which they grow—is the product, as we are accustomed to say, of heredity and variation. The variation within the group of offspring of the same parents is large—a very gifted thinker may have an almost feeble-minded brother—but the variation between families is real. A feeble-minded person's brothers will be feeble-minded hundreds of times as often.
The general average tendency of the original intellectual and moral natures of children to be like the original natures of their ancestry is guaranteed beforehand by the accepted principles of biology. Direct evidence of it is also furnished by investigations of the combination of original and acquired differences which human achievements, as they stand, display. The same studies which find differences of nurture hopelessly inadequate to account for differences of ability and achievement, find that original capacities and interests must be invoked precisely because achievement runs in families, and in a manner or degree which likeness in home training can not explain. Galton found that the real sons of eminent men had a thousand times the ordinary man's chance of eminence and far excelled the adopted sons of men of equal eminence. "Woods has shown that, when each individual is rated for intellect or morals, the achievements of those sons of royal families who succeeded to the throne by paternal death and thus had the special attention given to crown princes and the special unearned opportunities of succession, have, in the estimation of historians, been no greater than those of their younger brothers.
Children of the same parents resemble one another in every mental trait where the issue has been tested, and resemble one another nearly or quite as much in such tests as quickness in marking the A's on a sheet of printed capitals or giving the opposites of words, to which home training has never paid any special attention, as they do in adding or multiplying, where parental ambitions, advice and rewards would be expected to have much more effect, if they have any anywhere.
Mr. Courtis, who has been assiduously studying the details of ability
