No one will pretend that our so-called civilised society has a very strict practical morality, yet public opinion still seems to attach a particular importance to sexual morality, and this is the expression of a very real sentiment, the origin of which scientific sociology has no difficulty in retracing. This origin, far from being a lofty one, goes back simply to the right of proprietorship in women similar to that in goods and chattels--a proprietorship which we find claimed in savage, and even in barbarous countries, without any feeling of shame. During the lower stages of social evolution, women are uniformly treated as domestic animals; but this female live-stock are difficult to guard; for, on the one hand, they are much coveted and are unskilful in defending themselves, and on the other, they do not bend willingly to the one-sided duty of fidelity that is imposed on them. The masters, therefore, protect their own interests by a whole series of vexatious restraints, of rigorous punishments, and of ferocious revenges, left at first to the good pleasure of the marital proprietors, and afterwards regulated and codified. In the chapter on adultery, especially, will be found a great number of examples of this marital savagery. I have previously shown, in my _Evolution de la Morale_, that the unforeseen result of all this jealous fury has been to endow humanity, and more particularly women, with the delicate sentiment of modesty, unknown to the animal world and to primitive man. From this evolution of thousands of years there has finally resulted, in countries and races more or less civilised, a certain sexual morality, which is half instinctive, and varies according to time and place, but which it is impossible to transgress without the risk of offending gravely against public opinion. Civilisations, however, whether coarse or refined, differ from each other. Certain actions, counted as blameworthy in one part of the world, are elsewhere held as lawful and even praiseworthy. In order to trace the origin of marriage and of the family, it is therefore indispensable to relate a number of practices which may be scandalous in our eyes. While submitting to this necessity, I have done so unwillingly, and with all the sobriety which befits the subject. I have striven never to depart from the scientific spirit, which purifies everything, and renders even indecency decent.