Galton makes it plain that civilised man, by his sympathy with weak, inefficient individuals, has helped to continue their existence. This tendency on its own side has lessened the possibility of the efficient individuals to continue the species. Wallace, too, and several others, have on different occasions declared that men in relation to this question must have harder hearts, if the human race is not to become inferior. The moral, social, and sympathetic factors, they say, which in humanity work against the law of the survival of the fittest, and have made it possible for the lower type, to continue and to multiply in excess, must give way to new points of view where certain moral and social questions are concerned. So the natural law will be supported by altruism, instead of as now being opposed by this sentiment. Spencer's thoughts contain a great truth. They have been quoted in just this connection. He says: We see the germ of many things that later on are developed in a way no one now suspects. Profound transformations are worked in society and its members, transformations which we could not have hoped for as immediate results, but which we could have looked for in confidence as final consequences. The effort to find natural laws which cause racial progress or deterioration is one of these germinal ideas. As to scientific investigation in this field, we can apply another maxim of the same thinker, one often overlooked by science. "The passion to discover truth must be accompanied by the passion to use it for the welfare of mankind." But science must really reach universally accepted conclusions before we can expect humanity to begin seriously its self-purification; but it is certain to come then. When we read in ethnographical and sociological works what restrictions in marriage are imposed by savage people on themselves, and religiously obeyed on the ground of superstitious prejudice, we have a right to hope that civilised men will one day bow before scientific proofs. This hope is not too optimistic. Wallace pleads not for such absolute regulations as Galton, in order to prevent the marriages of the less worthy and to encourage the marriages of the superior types of humanity. He perceives that the problem is tremendously complicated. One thing is, that the personal attraction of love is extremely essential from the point of view of the improvement of the race. If human beings could be bred like prize cattle, it is not likely that a superior type of humanity would be produced. In the Middle Ages, the human race deteriorated, Galton said, because the best fled to the monasteries and the worst reproduced themselves. But if Galton's strict requirements had to be carried out in every case before a marriage could be allowed, not only would marriage lose its deepest meaning, but the race also would lose its noblest inheritance.