2. The human female and the mare copulate after conception more than any other creatures, for all other females, when they have conceived, fly from the males, except those which, like the hare, become pregnant a second time during gestation. But the mare, having once conceived, does not form a second fœtus, but generally produces a single foal. In the human subject it happens sometimes, though rarely. Those which are conceived a long while afterwards never come to perfection, but, from the pain which they cause, destroy the original fœtus; and a case has occurred in which twelve imperfect embryos have been produced at one time. If the second conception take place soon after the first, they bear and produce the fœtus, as if it were a twin. This, they say, was the case with Iphicles and Hercules. 3. The possibility of the case is manifest, for an adulteress has been known to produce one child like her husband, and another like her paramour; and a case has occurred of a woman having conceived twins, and then conceived a third child upon them; and when the proper time came, the twins were born perfect, the other was only a fœtus of five months old, which died immediately: and in another case, a woman produced, first of all, a fœtus of seven months old, and then twins, perfectly developed; the former perished, but the latter survived. And some women have conceived at the same time as they miscarried, and have ejected one fœtus while they bore the other. In most females, who have cohabited after the eighth month after conception, the child has been born filled with a shining mucous-like substance, and has often appeared full of the food which has been eaten by the mother; and if she has fed upon food more than usually salt, the child has been born without nails. CHAPTER VI. 1. The milk that is produced before the seventh month is useless; but as soon as the child is alive the milk becomes good. At first it is salt, like that of sheep. Most women during pregnancy are affected by wine, and if they drink it they become faint and feeble. The beginning and the ending of the reproductive power in both sexes is marked in the male by the emission of the semen, in the female by the catamenia. They are not, however, fertile when these first occur, nor while they are still small and weak. The period of the commencement of these signs has been mentioned. In women the catamenia usually cease at forty; but if they pass over this age, they go on to fifty; and some have even produced children at that period, but none later than this period.