H2 BIOMETRY 



character. The estimations were made by teachers 

 having at least six months' experience of the children 

 in question. 



The method of statistical treatment was, as we have 

 said, the same as that employed in the case of physical 

 characters not capable of quantitative measurement, 

 and there is little doubt that it is equally valid in the 

 present case. We may well feel, however, some 

 hesitation in accepting as sound the data to which the 

 method is applied. At the best this data can only be 

 of a roughly approximate kind. The evidence is, 

 however, undoubtedly sufficient to establish the con- 

 clusion that mental characters are inherited in man, 

 and that they are probably inherited at a rate not 

 greatly different from that at which physical characters 

 are inherited. For it will be observed that the values 

 given in Table VII. are in close agreement with one 

 another, and that they also agree with the average 

 value of fraternal correlation as found for a variety of 

 physical characters both in men and in other animals. 

 Assuming and the assumption seems to be a reasonable 

 one that equal fraternal correlations indicate the exist- 

 ence of equal correlations between parents and children, 

 we arrive at the conclusion that the resemblance 

 between parents and their offspring is of much the 

 same kind and amount in the case of mental as it is in 

 the case of bodily characteristics. 



What we may perhaps describe as the main general- 

 ization so far arrived at by biometricians is known 

 as the Law of Ancestral Heredity. This hypothesis 

 supposes, or at least in its original form supposed, that 



