The hymen has played a very definite and pronounced part in the social and moral life of humanity. Until recently it has been more difficult to decide what precise biological function it has exercised to ensure its development and preservation. Sexual selection, no doubt, has worked in its favor, but that influence has been very limited and comparatively very recent. Virginity is not usually of any value among peoples who are entirely primitive. Indeed, even in the classic civilization which we inherit, it is easy to show that the virgin and the admiration for virginity are of late growth; the virgin goddesses were not originally virgins in our modern sense. Diana was the many-breasted patroness of childbirth before she became the chaste and solitary huntress, for the earliest distinction would appear to have been simply between the woman who was attached to a man and the woman who followed an earlier rule of freedom and independence; it was a later notion to suppose that the latter woman was debarred from sexual intercourse. We certainly must not seek the origin of the hymen in sexual selection; we must find it in natural selection. And here it might seem at first sight that we come upon a contradiction in Nature, for Nature is always devising contrivances to secure the maximum amount of fertilization. "Increase and multiply" is so obviously the command of Nature that the Hebrews, with their usual insight, unhesitatingly dared to place it in the mouth of Jehovah. But the hymen is a barrier to fertilization. It has, however, always to be remembered that as we rise in the zoölogical scale, and as the period of gestation lengthens and the possible number of offspring is fewer, it becomes constantly more essential that fertilization shall be effective rather than easy; the fewer the progeny the more necessary it is that they shall be vigorous enough to survive. There can be little doubt that, as one or two writers have already suggested, the hymen owes its development to the fact that its influence is on the side of effective fertilization. It is an obstacle to the impregnation of the young female by immature, aged, or feeble males. The hymen is thus an anatomical expression of that admiration of force which marks the female in her choice of a mate. So regarded, it is an interesting example of the intimate manner in which sexual selection is really based on natural selection. Sexual selection is but the translation into psychic terms of a process which has already found expression in the physical texture of the body.