"Hérédité de la Couleur des Yeux dans l'espèce humaine," Archives des Sciences physiques et naturelles, sér. iii, vol. xii, 1884, p. 109.
Revue Scientifique, Jan., 1891.
F. Galton, Natural Inheritance, p. 85. It may be remarked that while Galton's tables on page 206 show a slight excess of disparity as regards sexual selection in stature, in regard to eye color they anticipate Karl Pearson's more extensive data and in marriages of disparity show a decided deficiency of observed over chance results. In English Men of Science (pp. 28-33), also, Galton found that among the parents parity decidedly prevailed over disparity (78 to 31) alike as regards temperament, hair color, and eye color.
Karl Pearson, Phil. Trans. Royal Society, vol. clxxxvii, p. 273, and vol. cxcv, p. 113; Proceedings of the Royal Society, vol. lxvi, p. 28; Grammar of Science, second edition, 1900, pp. 425 et seq.; Biometrika, November, 1903. The last-named periodical also contains a study on "Assortative Mating in Man," bringing forward evidence to show that, apart from environmental influence, "length of life is a character which is subject to selection;" that is to say, the long-lived tend to marry the long-lived, and the short-lived to marry the short-lived.