On the Secrets of Women

since it expels the coarse humidity of the woman by means of the flow. And we see an experiment: when there is in an animal body some coarse humor, harmful to the body, nature turns it into the official parts of the body, making scabby feet and hands, so that that humidity does not eat the principal members, namely the heart, the liver, and others.

Fourthly, someone might doubt whence the menses would come in a woman when she is in intercourse with a man, because it was said above that when a woman conceives, the menses are retained: therefore, if they were retained, it is strange whence they then flow during intercourse. To this it must be said that when a woman conceives, the menses are retained because of this final cause, so that from the retained menses, the fetus existing in the woman's womb may be nourished. But when a woman is in intercourse with a man, then because of the great pleasure which she has, because through the male organ existing in the vulva, the nerves and veins existing in the vulva are rubbed and moved: and thus the vulva, by dilating, emits [them], and this is natural with respect to intercourse, because that intercourse is natural. It is nevertheless quasi-violent with respect to the natural flow of the menses. Also, every day from the food consumed, matter is made which is naturally suited to be expelled in intercourse. And by that, the doubt is solved as to why pregnant women most desire intercourse: because the appetite for intercourse is due to the abundance of superfluous matter from food. And therefore, when the menses are retained