Two Object-Lessons in Heredity
THERE has just been published a history of what is called the Kallikak family. The name, however, is fictitious. The father descended from a long line of good English ancestry. He at first had criminal intercourse with a feeble-minded girl. The result was a feeble-minded son. This son married a normal woman. They in turn produced five feeble-minded and two normal children. Practically all the descendants of these defectives have been traced, as well as those of the two normals. From both lines, normal and defective, has come a long line of defective stock, 480 in all. Of these, 36 were illegitimate, 24 confirmed alcoholics, 3 epileptics, 33 sexually immoral, 82 died in infancy, three were criminal, 8 kept houses of ill fame, and 143 were distinctly feeble-minded. Only 46 were found who were apparently normal. The rest are unknown or doubtful. But the originator of this stock, after the Revolutionary War was over, married a Quaker girl of good ancestry, and settled down to live a respectable life. From this legal union with a normal woman, there have been 496 descendants. All of these except two have been of normal mentality, and these were cases of insanity, presumably inherited through marriage with an outside strain. In all the 496, there is not an instance of feeble-mindedness. The offspring have universally occupied positions in the upper walks of life. They have never been criminals or “ne’er-do-wells.” While, on the other hand, from the feeble-minded woman there has not been a single instance of exceptional ability. Most of them have failed to rise above the dead level of mediocrity, while most of them have fallen far below this minimum standard.