Page:Popular Science Monthly Volume 83.djvu/139

Rh It is not by a timid conservatism sticking to every jot and tittle of the customs which gifted men of the past have taught the world, that we shall prevent backsliding: it is far safer to trust gifted men of the present and future to keep what is good in our traditions, and to improve them. The only safe way to conserve the good wrought by the past is to improve on it.

It is beyond the province of this lecture to devise biologically helpful and socially innocuous schemes of selective breeding, but I may be permitted to record my faith that if mankind to-day really wanted to improve the original nature of its grandchildren as much, say, as it wants to improve the conditions of life for itself and its children, and believed certain facts of biology and psychology as effectively, say, as it believes that wealth gives power or that disease brings misery, appropriate schemes for selective breeding would be devised well within the span of our own lives.

Any form of socially innocuous selective breeding will improve the stock by reproducing from those members of it who have shown, by ancestral and personal achievement, with due allowance for favorable or unfavorable circumstances, the superiority of the germ plasm which they bear. But some forms may be far more effective than others according to the way in which the original components of intellect, character, energy, skill, stability and the like in the germs are constituted. Suppose, for example, that the original germinal basis for human intellect consisted in the presence of a certain constant something, call it $$I_{n}$$, the determiner for intellect," in the germ or ovum. The fertilized ovum, which is the human life at its beginning, could then have $$I_{n}$$ double, if both the germ and ovum had it; $$I_{n}$$ single if one or the other had it; or could lack $$I_{n}$$ as it must if neither had it. Suppose that the consequences of these three conditions were that the $$I_{n}I_{n}$$ individuals would tend, with fair conditions in life, to be specially gifted; that the In individuals would tend to be of "normal" intellect; that the individuals lacking $$I_{n}$$ would tend to be feeble-minded. It is then the case that of the germs produced by the individual who had $$I_{n}I_{n}$$ at the start of his life, each contains $$I_{n}$$, that of the germs produced by the individual who had $$I_{n}$$ at the start of his life, half have $$I_{n}$$ and half lack it, and that of the germs produced by the individual who lacked $$I_{n}$$ at the start of his life, no one has $$I_{n}$$. Consequently, by discovering the individuals who lacked $$I_{n}$$ at the start of life and preventing them from breeding, we could rapidly reduce feeble-mindedness. By discovering the individuals who had $$I_{n}I_{n}$$ at the start of life and breeding exclusively from them, we could eradicate feeble-mindedness and ordinariness both, leaving a race of only the specially gifted. The discovery could be made in a few generations of experimental breeding; and the exclusion, of course, could be made one generation after the discovery.