It is not only among birds that the female sometimes takes the active part, but also among mammals. Among white rats, for instance, the males are exceptionally eager. Steinach, who has made many valuable experiments on these animals (_Archiv für die Gesammte Physiologie_, Bd. lvi, 1894, p. 319), tells us that, when a female white rat is introduced into the cage of a male, he at once leaves off eating, or whatever else he may be doing, becomes indifferent to noises or any other source of distraction, and devotes himself entirely to her. If, however, he is introduced into her cage the new environment renders him nervous and suspicious, and then it is she who takes the active part, trying to attract him in every way. The impetuosity during heat of female animals of various species, when at length admitted to the male, is indeed well known to all who are familiar with animals. I have referred to the frequency with which, in the human species,--and very markedly in early adolescence, when the sexual impulse is in a high degree unconscious and unrestrainedly instinctive,--similar manifestations may often be noted. We have to recognize that they are not necessarily abnormal and still less pathological. They merely represent the unseasonable apparition of a tendency which in due subordination is implied in the phases of courtship throughout the animal world. Among some peoples and in some stages of culture, tending to withdraw the men from women and the thought of women, this phase of courtship and this attitude assume a prominence which is absolutely normal. The literature of the Middle Ages presents a state of society in which men were devoted to war and to warlike sports, while the women took the more active part in love-making. The medieval poets represent women as actively encouraging backward lovers, and as delighting to offer to great heroes the chastity they had preserved, sometimes entering their bed-chambers at night. Schultz (_Das Höfische Leben_, Bd. i, pp. 594-598) considers that these representations are not exaggerated. Cf. Krabbes, _Die Frau im Altfranzösischen Karls-Epos_, 1884, p. 20 et seq.; and M.A. Potter, _Sohrab and Rustem_, 1902, pp. 152-163.