The growing depravity of customs, furthermore, threatens us with no less a danger. I do not wish to exaggerate the horrors of the modern Babylons, as Catholic priests and Protestant ministers are apt to do. Their grief at seeing the rising generation turn a deaf ear to their wise counsels makes them take too gloomy a view of the present state of affairs. Nevertheless, it is certain that the customs of modern civilisation are hurrying it towards a dangerous crisis. The internal restraints are being relaxed, and temptations and facilities are multiplying with the growth of riches and of cities, and with the increasing mobility of persons of both sexes, so many of whom it prompts to leave their native village or country. Especially in the big cities where everyone is unknown, can easily hide away, and is watched by nobody; where money has greater power over men’s minds because there is more of it and more of it is needed,—virtue runs serious and continual risks. Without being aware of it, we are undoing, little by little, Christianity’s great contribution to the chastening of our customs, by suppressing many of the limits which Christianity had established with such labour in the midst of the unbridled licence of the ancient world. We are travelling, therefore, step by step back towards paganism, with all its conveniences and all its perils. Already, in fact, we can see cropping up here and there in the richer and more highly civilised countries and classes that mortal sickness which killed the ancient civilisations: sterility. One of the reasons why all the most flourishing ancient civilisations have perished is that at the moment of their greatest glory the population suddenly began to dwindle; and this sterility which killed them was the effect to a large extent of the licence of their customs. Love remains fertile only so long as it restrains itself and limits itself. Christianity, by subjecting men’s customs to discipline—one of the noblest of its services to mankind—succeeded for centuries in maintaining in Europe and America an incessant fertility, which has proved to be one of the most potent causes of the increase of our power. But now we can see, with the return of the world to paganism, the beginning of a new era of sterility, especially in the big cities and in the most ancient and most wealthy states.