CHAPTER III 



INHERITANCE AND VARIATION IN MANKIND 



THE inheritance by children of some share of their 

 parents' qualities is a matter of common observation. 

 The transmission seems at first sight to be capricious, 

 but the very attention which is drawn to any marked 

 departure from family type shows that the power of 

 heredity is recognised by general consent. 



A moment's reflection suggests that the capricious- 

 ness is a question of the individual, and that, on taking 

 a large number of cases, we should expect to find 

 definite laws holding good, as we do in other forms of 

 life. 



The qualities we desire in plants and animals are 

 comparatively simple ; those which give to man his 

 dignity and value are extremely complex. The problem 

 of tracing the descent of hereditary characters in man- 

 kind is much more difficult. Nevertheless, that problem 

 was attacked systematically by Sir Francis Galton as 

 early as 1869, and his great works on Hereditary 

 Genius and Natural Inheritance stand as landmarks in 

 the subject. 



Since that date the study of inheritance in plants 

 and animals has been revolutionized by the rediscovery 



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