iv] STATISTICAL STUDY 49 



likely to have exceptional sons than are mediocre 

 men, and if the mother is also exceptional in the 

 same direction this probability is greatly increased. 

 In the last few years the intensity of inheritance 

 in such characters has been given numerical ex- 

 pression. Professor Pearson, after working out the 

 statistical laws of inheritance in many physical char- 

 acters of man, animals and plants, has applied the 

 same methods to what are called the mental and 

 moral attributes. Characters were chosen such as 

 vivacity, popularity, conscientiousness, temper, ability, 

 hand-writing, which were estimated by reports from 

 school-teachers on the children in their schools ; 

 and also intellectual ability as shown in university 

 examinations or by the position in a public school 

 at a particular age (Schuster [10]) 1 . All these, when 

 investigated by the same methods as were devised 

 for the coat-colour of horses or eye-colour in man, 

 are found to give results closely in accord with those 

 obtained for physical features. The conclusion is 

 therefore reached that not only bodily characters, 

 but also those of the mind are essentially determined 

 by the hereditary endowment received from the 

 parents. This result is of great importance practi- 



1 In these characters the resemblance between parent and child 

 cannot of course be estimated directly, but it has been pointed out 

 above that the resemblance between brothers may be used as a test 

 of the intensity of heredity. 



D. 4 



