The proportion between the sexes varies among different peoples, pp. 460-464.—Causes to which the disparity in the numbers of the sexes is due, pp. 465-482.—The higher mortality of men, dependent upon war, &c., pp. 465, _et seq._—The higher mortality of women, dependent upon female infanticide, &c., p. 466.—Disproportion between the sexes at birth, pp. 466-469.—Hypotheses as to the causes which determine the sex of the offspring, pp. 469-476.—The law of Hofacker and Sadler, pp. 469, _et seq._—Dr. Düsing’s hypothesis, pp. 470-476.—Polyandry dependent upon an excess of male births, pp. 472-474.—Coincidence of polyandry with poverty of material resources, pp. 474-476.—Mixture of race produces an excess of female births, pp. 476-480.—Unions between related individuals or, generally, between individuals who are very like each other, produce a comparatively great number of male offspring, pp. 480-482.—The form of marriage influenced by the numerical proportion between the sexes, pp. 482, _et seq._—Several reasons why a man may desire to possess more than one wife, pp. 483-492.—Monogamy requires from him periodical continence, pp. 483-485.—He is attracted by female youth and beauty, pp. 485, _et seq._—At the lower stages of civilization women become old sooner than in more advanced communities, pp. 486-488.—Man’s taste for variety, p. 488.—Man’s desire for offspring, pp. 488-491.—Women generally less prolific among savage than among civilized nations, pp. 490, _et seq._—A man’s fortune increased by a multitude of wives through their labour, pp. 491, _et seq._—A man’s authority increased by a multitude of wives, p. 492.—Hindrances to polygyny, pp. 493-503.—The difficulty in maintaining a plurality of wives, p. 493.—The necessity of paying the purchase-sum or of serving for a wife, pp. 493, _et seq._—Polygyny practised chiefly by the principal men of the people, pp. 494, _et seq._—Polygyny a violation of the feelings of women, pp. 495-500.—Marrying sisters, pp. 499, _et seq._—Coincidence of monogamy with a higher _status_ of women, pp. 500-502.—The form of marriage influenced by the quality of the passion which unites the sexes, p. 502.—The absorbing passion for one, pp. 502, _et seq._—The causes of polyandry, pp. 503, _et seq._—The chief immediate cause a numerical disproportion between the sexes, p. 504. CHAPTER XXII THE FORMS OF HUMAN MARRIAGE (_Concluded_)