Page:Popular Science Monthly Volume 84.djvu/389

Rh This second part of the problem of human betterment, real race betterment, is a problem of good breeding, not one of culture. This problem of good breeding has two somewhat distinct aspects that are seldom clearly distinguished. There is first the problem of bringing the race average nearer to its present best by eliminating the less desirable and breeding from the best. This is the problem of eugenics as ordinarily considered. But there is the added problem of securing further true evolution of the race, raising the present best to a better.

We see thus the three aspects of the problem of human betterment: first, human culture, whose effects are cumulative through training from generation to generation, though not inherited; second, racebetterment through breeding from the best and eliminating the more undesirable, thus raising the general average toward the best type of manhood as we know it; third, the problem of securing true evolution beyond the point of the best yet experienced among men.

The problem of human culture is social, not biological. The problems of eugenics and evolution are primarily biological, but can be approached only if social conditions allow the application of biological method. It is necessary to emphasize cultural effort, for it is essential that the good breeding of the future human race be in the midst of a controlling atmosphere of highest altruistic idealism. Let us note for a moment some elements of the biological problem.

I can not stop to describe the microscopical structure of germ cells and their nuclei; the fact that the nuclei contain chromosomes in definite number which are the instigators of physiological action and the controllers in heredity; that the chromosomes in each nucleus fall into diverse categories physiologically, there being two chromosomes of each physiological type, one derived from the male parent and one from the female parent; that the different regions of a single chromosome may have different physiological values, and that in the division of nuclei the chromosomes split in such a manner that each daughter cell receives half of each specialized bit of each chromosome; that before fertilization one chromosome of each physiological pair is thrown away, and that in fertilization the full double character of the nucleus is restored. Of course, without knowledge of these structures in the germ cells and of their behavior in reproduction, one is not ready to begin to think of problems of inheritance. Familiarity with these fundamental facts not only helps one to escape many errors into which so many of the uninitiated fall, as, for example, the belief in the inheritance of the effects of culture, that is, of acquired characters, but it is essential as a guide to every step of one's thinking in this field. But I must assume that these are familiar matters to you all.

Recent studies in heredity have demonstrated that there is a sharp distinction between qualities that are heritable and others that are not