by it, whereas the extremely low grade boy may not be up to his school education in zeal or capacity and the extremely high grade boy may get on better without it. So also with high school education. On the other hand, post graduate instruction to which women are flocking in great numbers is, at least in its higher reaches, a far more remunerative social investment in the case of men.” (“Sex in Education,” _Bookman_, Vol. XXIII, April, 1906, p. 213.) Before we begin the revision of our educational systems in accordance with this theory, we must make sure that it really explains away the “female geniuses.” For although the theory is still widely held by biologists and psychologists, it requires only a short study to discover how tenuous is the evidence adduced in support of it--in all its phases, but especially in regard to mental traits. Darwin apparently gave no statistical evidence to support “the principle,” as he called it, and those who have followed him have done little to fill the lack. Professor Hall offers evidence that is almost entirely empirical; Havelock Ellis has been attacked by Karl Pearson for doing much “to perpetuate some of the worst of the pseudo-scientific superstitions to which he [Ellis] refers, notably that of the greater variability of the male human being.” Professor Thorndike, in spite of his conclusions, admits that it “is unfortunate that so little information is available for a study of sex differences in the variability of mental traits in the case of individuals over fifteen.” And while the overwhelming majority of Professor Cattell’s 1000 eminent characters are men, he merely states without proving his explanation that “woman departs less from the normal than man.” Wise feminists to-day are concentrating their forces upon this theory. Women have won the right to an acknowledged mind; they want now the right to draw for genius and high talents in the “curve of chance.” And this is no merely academic question. For while genius may overcome the sternest physical barriers of environment, it is nourished and developed by tolerant expectancy. Men may accomplish anything, popular thought tells them, and so some men do. But if women are scientifically excluded from the popular expectation of big things, if their educations are toned down to preparation for “the average level,” if motherhood remains the _only_ respected career for _all_ women, then the female geniuses will remain few and far between. And, more important still, all thinking women will continue restless over the problem of how to secure the chance to vary in interests and abilities from the average of their sex, and at the same time to be wives and mothers.