Page:Popular Science Monthly Volume 71.djvu/405

Rh we can not go backwards a single step in the evolution of human feeling! But I demand that sympathy and charity shall be organized and guided into paths where they will promote racial efficiency, and not lead us straight towards national shipwreck. The time is coming when we must consciously carry out that purification of the state and race which has hitherto been the work of the unconscious cosmic process. The higher patriotism and the pride of race must come to our aid in stemming deterioration; the science of eugenics has not only to furnish Plato's legislator with the facts upon which he can take action, but it has to educate public opinion until without a despotism he may attempt even the mildest purgation. To produce a nation healthy alike in mind and body must become a fixed idea—one of almost religious intensity, as Francis Galton has expressed it—in the minds of the intellectual oligarchy, which after all sways the masses and their political leaders.

Let me put before you a little more in detail the biological aspects of national growth. The Darwinian hypothesis asserts that the sounder individual has more chance of surviving in the contest with physical and organic environment. It is therefore better able to produce and rear offspring, which in their turn inherit its advantageous characters. Profitable variations are thus seized on by natural selection, and perpetuated by heredity.

Now if we are to apply these biological ideas to the case of man, we must have evidence (1) that man varies, (2) that these variations, favorable or unfavorable, are inherited, and (3) that they are selected.

Is it needful now to show that man varies? We not only know he varies, but the extent of variation in both man and woman has been measured by the biometric school in nearly two hundred cases. The variability within any single local race of man amounts from 4 or 5 to 15 to 20 per cent, of the absolute value of the character.

Secondly, are these variations inherited? Of this there is not the slightest doubt. They are not mere somatic fluctuations, but correspond to real geminal differences. The problem of inheritance is closely associated with that of the resemblance of members of the same stock, due caution being paid to the possibilities of environmental influence. Xow we may separate the characters in which we are at present interested into three: (a) the physical, (b) the pathological and (c) the psychical.

Table II. gives us the resemblance between parent and offspring for a number of physical characters in man. Please note that the coefficient recorded is zero if there be no relationship and unity, if parent and offspring show an invariable relationship in the character under discussion. We see that the resemblance in the case of man lies between .4 and .5. It is about half-way up the correlation scale. Again the lower part of Table II, gives us corresponding measures of resemblance