THE INHERITANCE OF MENTAL ABILITY 99 



"The influence of heredity, which it is now the fashion to rate so 

 highly, is as nothing compared with the influences which mold 

 the man after he comes into the world." 



The establishment of the theory of evolution, and its applica- 

 tion to the development of mankind could scarcely fail to direct 

 renewed attention to the inheritance of mental qualities in man. 

 Inspired by this doctrine and stimulated by the writings and 

 personal influence of his cousin, Charles Darwin, Francis Galton 

 was led to undertake those studies on inheritance by which he has 

 since become famous. The investigations which Galton made 

 upon the inheritance of ability were embodied in his celebrated 

 volume on Hereditary Genius. In this work Galton showed that 

 superior ability runs in certain families to a very marked degree. 

 We are all familiar with families which are celebrated for the 

 number of their great names: In science, the Herschels, Ber- 

 nouillis, De Candolles, Darwins and Gregorys; in literature, 

 the Brontes, the Arnolds, the Hallams, and the Lowells; in music, 

 the Bachs and the Mendelssohns. It might be contended that the 

 occurrence of such groups is purely fortuitous. Even if there were 

 no transmission of ability or any other reason why persons of the 

 same family should become distinguished it would be possible, 

 from all the great men in the world, to pick out a considerable 

 number of cases in which two or more men of great abihty hap- 

 pened to belong to the same family. Galton, who was too critical 

 an investigator to base his case merely on evidence especially 

 selected to prove his theory, undertook an impartial statistical 

 inquiry into the families of eminent men in order to ascertain how 

 far the data obtained would yield evidence of the hereditary basis 

 of great abiUty. Eminent men were classified into several groups, 

 judges, scientists, literary men, statesmen, poets, musicians, 

 painters and divines. The basis for selection varied with the 

 different groups, but was in all cases made so as to include the 

 most eminent persons regardless of heredity. Then the endeavor 

 was made to determine to what degree eminent men in these 

 groups had eminent relatives. It was shown that eminent men 

 have eminent relatives to an enormously greater degree than do 



