It is improbable that the unions of quadrupeds in a state of nature should be left to mere chance. It is much more probable that the females are allured or excited by particular males, who possess certain characters in a higher degree than other males.[14] [14] _The Descent of Man_, 1877, p. 525. As the female among birds selects her partner, he thinks it would be a strange anomaly if among quadrupeds, which stand higher in the scale and have higher mental powers, she did not also exert a choice.[15] [15] It should be noted, in passing, that, according to this reasoning, the female of the human species would also be likely to exercise her will power in the selection of a mate. Evidences are indeed at hand going to prove that until a comparatively recent time in the history of the human race women controlled the sexual relation. As will be shown in Part II., during the primitive ages of human existence the position of woman was much higher than was that occupied by man. During the earlier ages, and under more natural conditions, women selected their mates, and among the human species, as among the lower orders, it became necessary for the male to please the female if he would win her favours; hence, through Sexual Selection, it is believed, was acquired the greater size of man. Because of the indifference of the female to the attentions of the male, in order to carry on the processes of reproduction, it was necessary among the lower orders that the male become eager in his pursuit of her, and as a result of this eagerness excessive passion was developed in him. As the most eager would be the most successful in propagating, they would leave the greatest number of offspring to inherit their characters—namely, in males, passion and pugnacity correlated with the physical qualities acquired through Sexual Selection. On the subject of the acquirement of secondary sexual characters, Mr. Darwin says: “The great eagerness of the males has thus indirectly led to their much more frequently developing secondary sexual characters.” Indeed, by all naturalists, the fact is recognized that the appearance of these characters is closely connected with the reproductive function. Later experiments have confirmed the observations of Mr. Darwin concerning the intelligence of the female among the lower orders of life. Among these experiments are those recently made by Professor Harper, of the Department of Biology, in the Northwestern University. Professor Harper announces that in all the experiments conducted by him, the female animal showed a greater degree of perception, or intelligence, than the male. He says: “In all my experiments, I found that the female displayed a remarkable quickness in grasping ideas which the male after numerous sluggish efforts finally accomplished.” Professor Harper declared that these facts regarding animals apply with equal force to human beings.