io8 THE TREND OF THE RACE 



The inheritance of arithmetical ability has been studied by 

 Cobb who applied the "Courtis Tests in Arithmetic Series A" 

 to the parents and children in eight families of the faculty of the 

 University of Illinois. The records were compared with norms 

 obtained by testing 200 students of the same institution of much 

 the same degree of maturity and social status. Cobb studied 

 particularly the relation between the aptitude for addition, 

 subtraction, multiplication, division and copying figures in both 

 parents and children. One individual may be good in addition 

 and poor in division, and the endeavor was made to find if the 

 relative of that individual would show the same distribution of 

 aptitudes. The results of the study yielded considerable indica- 

 tion of alternative inheritance of the traits in question. The 

 average correlation with the mid parent was .49, with the like 

 parent .60, with the unlike parent .01. The numbers of individ- 

 uals dealt with were too small to yield results which would be 

 convincing by themselves, but they serve to corroborate the 

 general conclusions of other investigatiors. The studies of 

 Starch on the resemblance in the performance of scholars from 

 the same family yield further confirmatory evidence. 



Next to Galton's Hereditary Genius perhaps the best known 

 investigation of the inheritance of mental traits is the work of 

 Woods on Mental and Moral Heredity in Royalty. Members of 

 royal families offer some peculiar advantages for such a study 

 since their genealogies are matters of record to a greater extent 

 than those of ordinary people; as a class they are free from the 

 struggle for livelihood and have usually enjoyed educational 

 advantages of a superior kind. Differences in environment 

 probably affect the intellectual development of royalty much less 

 than that of the majority of mankind. 



The study of Woods embraced all members of the royal families 

 of Europe about whom information could be secured. Individ- 

 uals were grouped according to their intellectual ability into ten 

 catagories, number i including those generally adjudged to be 

 imbeciles, number 10 including only a few of the most illustrious 

 names, while the great majority naturally fell into the intervening 



