THE PHYSICAL BASIS OF HEREDITY. 33 



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 mem- 

 bers 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 six- 

 teenth 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 genera- 

 tions 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 char- 

 acters 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 indi- 

 vidual 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 dis- 

 cussion 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 main- 

 tain 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 mold- 

 ing effects of activities and environment have individualized the par- 

 ents. Sargent, of the Harvard gymnasium, evidently convinced of the 

 transmissibility of acquired characters, advises the delay of marriage 



* With apologies to Dr. E. G. Conklin. 

 vol. lxi. — 3. 



