rapidly do they deteriorate. Yet you have risked man's earthly destiny on the fatuous notion that the "grandfather's environment is the grandchild's heredity"; that if you want to produce a genius, you must begin by educating the grandfather; that the sins of the fathers are visited upon the children; and that if the fathers have eaten sour grapes, it will set the children's teeth on edge. Now, in the sense in which you believe these things they are not true. Long ago biology has consigned them to the realm of myth and fancy. It would only bewilder you for me to say that in rare experimental situations permanent germinal modifications have probably been induced; but, speaking generally, parents can eat sour grapes for a thousand years and never affect the dental apparatus of the children. While the Hebrew prophets were merely speaking of criminal law and not of heredity, the sins of the fathers are not visited to any appreciable extent upon the children unless the fathers commit the one unpardonable biological sin of assortative mating with the sinful. But educating you or cultivating your morals will never directly cause your children to be born brighter of ore virtuous. If your father went crazy from getting hit on the head with a brickbat, you do not inherit his cracked brain, but only his inability to dodge brickbats. Stupidity begets stupidity, and intelligence begets brains; but a thousands[sic] years of educating or improving the parents will never "improve" the children. This is because the children are born, not from the "improved" body cells, but from the unimproved germ cells. Children are born, not from the body cells which you can educate but from the germ cells which by any method now know you cannot educate. In short, "Wooden legs are not inherited, but wooden heads are." [section symbol] 7 The sixth warning of biology to statesmanship is the bitter cry of the children. 9 [end]