Zacchia, mainly on _a priori_ grounds, concludes that women have more pleasure in coitus than men. (Zacchia, _Quæstiones Medico-legales_, 1630, lib. iii, quest, vii.) Sinibaldus, discussing whether men or women have more salacity, decides in favor of women. (J.B. Sinibaldus, _Geneanthropeia_, 1642, lib. ii, tract. ii, cap. v.) Hornius believed that women have greater sexual pleasure than men, though he mainly supported his opinion by the authority of classical poets. (Hornius, _Historic Naturalis_, 1670, lib. iii, cap. i.) Nenter describes what we may now call women's affectability, and considers that it makes them more prone than men to the sexual emotions, as is shown by the fact that, notwithstanding their modesty, they sometimes make sexual advances. This greater proneness of women to the sexual impulse is, he remarks, entirely natural and right, for the work of generation is mainly carried on by women, and love is its basis: "generationis fundamentum est amor." (G.P. Nenter, _Theoria Hominis Sani_, 1714, cap. v, memb. ii.) The above opinions of seventeenth-century physicians are quoted from the original sources. Schurig, in his _Gynæcologia_, (pp. 46-50 and 71-81), quotes a number of passages on this subject from medical authorities of the same period, on which I have not drawn. Sénancour, in his fine and suggestive book on love, first published in 1806, asks: "Has sexual pleasure the same power on the sex which less loudly demands it? It has more, at all events in some respects. The very vigor and laboriousness of men may lead them to neglect love, but the constant cares of maternity make women feel how important it must ever be to them. We must remember also that in men the special emotions of love only have a single focus, while in women the organs of lactation are united to those of conception. Our feelings are all determined by these material causes." (Sénancour, _De l'Amour_, fourth edition, 1834, vol. i, p. 68.) A later psychologist of love, this time a woman, Ellen Key, states that woman's erotic demands, though more silent than man's, are stronger. (Ellen Key, _Ueber Liebe und Ehe_, p. 138.) Michael Ryan considered that sexual enjoyment "is more delicious and protracted" in women, and ascribed this to a more sensitive nervous system, a finer and more delicate skin, more acute feelings, and the fact that in women the mammæ are the seat of a vivid sensibility in sympathy with the uterus. (M. Ryan, _Philosophy of Marriage_, 1837, p. 153.) Busch was inclined to think women have greater sexual pleasure than men. (D.W.H. Busch, _Das Geschlechtsleben des Weibes_, 1839, vol. i, p. 69.) Kobelt held that the anatomical conformation of the sexual organs in women led to the conclusion that this must be the case.