The Mosaic law regarded the process of menstruation as unclean in nature; the menstruating woman was unclean, and must be purified in a prescribed manner. In the fifteenth chapter of Leviticus, vv. 19–29, we read: “And if a woman have an issue, and her issue in her flesh be blood, she shall be put apart seven days: and whosoever toucheth her shall be unclean until the even. * * * Every bed whereon she lieth all the days of her issue shall be unto her as the bed of her separation. * * * But if she be cleansed of her issue, then she shall number to herself seven days, and after that she shall be clean. And on the eighth day she shall take unto her two turtles, or two young pigeons, and bring them unto the priest, to the door of the tabernacle of the congregation.” In a similar manner the adherents of the faith of Islam regard a menstruating woman as unclean. This view is found also in the earliest medical writings, alike in the early Indian book of _Susruta_ and in the later writings of _Hippocrates_, and it persists to the present day in the use of the expression “monthly purification.” _Susruta_ teaches that in India menstruation begins at the age of twelve, and recurs monthly, the flow lasting three days. In the Jewish Talmud it is asserted (see “La Médécine du Talmud,” by _Dr. Rabbinowicz_) that menstruation begins as soon as the girl has two hairs on the pubic region, or at the age of twelve, even in the absence of any growth of the pubic hair. The menstrual blood is quite peculiar in its characters. Thus, _Raschi_ relates, the mother of the King of Persia exhibited sixty varieties of blood, and among them _Rabba_ was able to detect which was the menstrual blood. According to a rabbinical authority, a woman can become pregnant as soon as she has completed her twelfth year. As signs of puberty, _Rabbi Jossé_ mentions the appearance of a fold beneath the nipple, _Rabbi Akiba_, the erection of the nipples, _Rabbi d’Azai_, the appearance of a dark areola around the nipples, _Rabbi Jossé_, the recession of the nipple under pressure followed by its gradual protrusion when the pressure is removed, also the softening of the mons Veneris (in consequence of the deposit of fat in its substance). As prodromal signs of the first appearance of menstruation, the Talmud mentions, pain in the region of the umbilicus and in the uterus, flatulence, shivering, white flux, heaviness in the head and the limbs, and nausea.