Every one of even the most useful and beneficent of human inventions has either exercised subtle injuries or produced appalling catastrophes. This is not only true of man's devices, it is true of Nature's in general. Let us take, for instance, the elevation of man's ancestors from the quadrupedal to the bipedal position. The experiment of making a series of four-footed animals walk on their hind-legs was very revolutionary and risky; it was far, far more beset by dangers than is the introduction of contraceptives; we are still suffering all sorts of serious evils in consequence of Nature's action in placing our remote ancestors in the erect position. Yet we feel that it was worth while; even those physicians who most emphasise the evil results of the erect position do not advise that we should go on all-fours. It is just the same with a great human device, the introduction of clothes. They have led to all sorts of new susceptibilities to disease and even tendencies to direct injury of many kinds. Yet no one advocates the complete disuse of all clothing on the ground that corsets have sometimes proved harmful. It would be just as absurd to advocate the complete abandonment of contraceptives on the ground that some of them have sometimes been misused. If it were not, indeed, that we are familiar with the lengths to which ignorance and prejudice may go we should question the sanity of anyone who put forward so foolish a proposition. Every great step which Nature and man have taken in the path of progress has been beset by dangers which are gladly risked because of the advantages involved. We have still to enumerate some of the immense advantages which Man has gained in acquiring a conscious and deliberate control of reproduction. III. BIRTH CONTROL IN RELATION TO MORALITY AND EUGENICS Anyone who has followed this discussion so far will not easily believe that a tendency so deeply rooted in Nature as Birth Control can ever be in opposition to Morality. It can only seem to be so when we confuse the eternal principles of Morality, whatever they may be, with their temporary applications, which are always becoming modified in adaptation to changing circumstances.