It remains to say something about the future effects of the anthropological sciences. This is of course extremely conjectural, because we do not know what discoveries will be made. The effect is likely to be far greater than we can now imagine, because these sciences are still in their infancy. I will, however, take a few points on which to hang conjectures. I do not wish to be supposed to be making prophecies: I am only suggesting possibilities which it may be instructive to consider. Birth-control is a matter of great importance, particularly in relation to the possibility of a world-government, which could hardly be stable if some nations increased their population much more rapidly than others. At present, birth-control is increasing in all civilized countries, though in most it is opposed by governments. This opposition is due partly to mere superstition and desire to conciliate the Catholic vote, partly to the desire for large armies and severe competition between wage-earners, so as to keep down wages. In spite of the opposition of governments, it seems probable that birth-control will lead to a stationary population in most white nations within the next fifty years. There can be no security that it will stop with a stationary population; it may go on to the point where the population diminishes. The increase in the practice of birth-control is an example of a process contrary to that seen in industrialism: it represents a victory of individual over collective passions. Collectively, Frenchmen desire that France should be populous, in order to be able to defeat her enemies in war. Individually, they desire that their own families should be small, in order to increase the inheritance of their children and to diminish the expense of education. The individual desire has triumphed over the collective desire, and even, in many cases, over religious scruples. In this case, as in most others, the individual desire is less harmful to the world than the collective desire: the man who acts from pure selfishness does less damage than the man who is actuated by “public spirit.” For, since medicine and sanitation have diminished the infant death-rate, the only checks to over-population that remain (apart from birth-control) are war and famine. So long as this continues to be the case, the world must either have a nearly stationary population, or employ war to produce famine. The latter method, which is that favoured by opponents of birth-control, has been adopted on a large scale since 1914; it is however somewhat wasteful. We require a certain number of cattle and sheep, and we take steps to secure the right number. If we were as indifferent about them as we are about human beings, we should produce far too many, and cause the surplus to die by the slow misery of under-feeding. Farmers would consider this plan extravagant, and humanitarians would consider it cruel. But where human beings are concerned, it is considered the only