Page:Popular Science Monthly Volume 61.djvu/39

Rh tendency to fatness and leanness and, in the males of certain families, a tendency to baldness. The members of some families have a tendency to become corpulent at a certain period, and no reasonable amount of starving seems to affect this tendency. After half the inmates of Andersonville prison had made their escape, one of these hereditarily stout individuals even after weeks of starving became fastened in the tunnel, preventing the escape of the rest of the prisoners. The members of other families remain 'hungry Cassiuses' however well they may be fed.

Mental peculiarities are transmissible. Sometimes one mental trait of the parents is transmitted to one child while others are transmitted to another. Weit Bach, a baker who lived in the middle of the sixteenth century, was a mild form of a musical prodigy. He transmitted his musical talent through at least eight generations, and hundreds of descendants, twenty-nine of whom became famous musicians. The case of the Jukes family is well known. In the course of six generations of descendants from one woman 52% of the female descendants became public women, 23% of the children were illegitimate. There were seven times more paupers among the women than among all women, and nine times as many among the men.

We have, then, characters that are always transmitted and characters that may be transmitted. As a third group we have characters concerning which we have doubt, and, at present, much discussion. This third group of characters includes individual peculiarities which have not been inherited, but are acquired during the lifetime of the individual as the result of his education, his activities and the effect of the climate and other elements of his environment. Whether or not these are transmissible has. been the question of the past ten years. The discussion was started by Weismann, who denied, for theoretic reasons, that any of the characters so produced are transmissible. It is agreed that the individual characters that result from accidental or voluntary mutilations are not transmitted. Wooden legs are never transmitted. Wooden heads sometimes are! Many instances have been brought forward to prove the transmissibility of acquired characters, but none of these cases has been accepted as conclusive. From my own studies of the effect of disuse on eyes and the absence of light on color, I am convinced that the results of the activities and the characters due to the environment are transmissible. Mehnert goes so far as to maintain that races are progressing in so far as marriage does not take place until comparatively late in life, and children are not born till the molding effects of activities and environment have individualized the parents. Sargent, of the Harvard gymnasium, evidently convinced of the transmissibility of acquired characters, advises the delay of marriage