54 THE FAMILY AND THE NATION 



On the other hand, the influence of heredity is well 

 marked. The statistics show that the coefficient of 

 correlation lies between 0.4 and 0.6, thus agreeing 

 with the intensity of inheritance of other physical 

 characters, such as stature. The preponderating in- 

 fluence of heredity again becomes evident, even where 

 we might expect that environment would play a 

 conspicuous part. 



The study of variation in mankind has been post- 

 poned till now in order that the facts of inheritance 

 given above should be held in mind. For, leaving 

 aside for the moment acquired characters, it is impossible 

 rightly to understand variations in innate quaHties till 

 we have some knowledge of heredity, by which those 

 qualities are determined. 



The work of Johannsen on pure lines, described 

 on page 30, suggests that, for variations to be trans- 

 mitted by heredity, they must themselves be derived 

 from chance germinal associations of different qualities 

 obtained from various individuals in a heterogeneous 

 ancestry, or, at all events, that such ancestral varia- 

 tions are of far more hereditary importance than 

 others. Sports arise from the chance combination 

 of different factors, producing an unexpected result. 

 Drawn from different individuals in an ancestral 

 tree, the factors form a particular conjunction, which 

 perhaps has never before happened, and the result is a 

 dwarf, a giant, or a transcendent genius. If some of 

 the factors happen to have an affinity for each other, 

 they become linked in the manner traced in recent 



