To round out this evidence Doctors Leta Hollingworth and Helen Montague measured 20,000 infants at their birth in the maternity wards of the New York Infirmary for Women and Children. They sought to discover whether environmental influences played any determining rôle in producing the results obtained by Pearson from measurements upon adults. From the ten anatomical measurements made upon these babies they found that “in all cases the differences in variability are very slight. In only two cases does the percentile variation differ in the first decimal place. In these two cases the variability is once greater for males and once greater for females.” (“The Comparative Variability of the Sexes at Birth,” _American Journal of Sociology_, Vol. XX, 1914-1915, pp. 335-370.) The findings on anatomical variability do not, of course, necessarily prove anything about differences in the range of mental ability. They do, however, suggest the probability of parallel results and such studies as have been made tend, on the whole, to bear this out. All the recent work in this field (and it is still fragmentary) seems to point at least to equal mental variability among men and women. In 1917, Terman and others in their “Stanford Revision of the Binet-Simon Scale for Measuring Intelligence” investigated this problem among school children from five to fourteen years old. They obtained the Intelligence Quotients of 457 boys and 448 girls and compared these I.Q.’s with teachers’ estimates and judgments of intelligence and work and with the age grade distribution of the sexes for the ages of 7 to 14. After making all necessary qualifications, they concluded that the tests revealed a small superiority in the intelligence of the girls that “probably rests upon a real superiority in intelligence, age for age.” But “apart from the small superiority of the girls, the distribution of intelligence shows no significant differences in the sexes. The data offer no support to the wide-spread belief that girls group themselves more closely about the median or that extremes of intelligence are more common among boys” (p. 83). Dr. Hollingworth, again, has made a study of mental differences for adults. She has summarized the results of recent studies in sex differences in mental variability and in tastes, perceptions, interests, etc. Her conclusions on this score are interesting: “(1) The greater variability of males in anatomical traits is not established, but is debated by authorities of perhaps equal competence. (2) But even if it were established, it would only suggest, not prove, that men are more variable in mental traits also. The empirical data at present available on this point are inadequate and contradictory, and if they point either way, actually indicate greater female variability....” (“Variability as Related to Sex Differences in Achievement,” _American Journal of Sociology_, Vol. XIX, pp. 510-530, Jan., 1914.)