220 HEREDITY AND ENVIRONMENT 



are, on the average, more like their kind than 

 like anything else" (Brooks). 



There seems to be no reason to doubt that 

 all the extraordinary differences which organ- 

 isms show, as well as all of their resemblances, 

 are due to differences or resemblances in the 

 hereditary and environmental factors which 

 have been operative in their development. But 

 in view of this universal variability of organ- 

 isms it is not surprising that inheritance has 

 seemed capricious and uncertain, — "a sort of 

 maze in which science loses itself." 



B. STATISTICAL STUDY OF INHERITANCE 



Francis Galton was one of the first who at- 

 tempted to reduce the mass of conflicting ob- 

 servations on heredity and variation to some 

 system and to establish certain principles as a 

 result of statistical study. He was the real 

 founder of the scientific study of inheritance; 

 he studied characters singly and he introduced 

 quantitative measures. Galton's researches, 

 which were published in several volumes, con- 

 sisted chiefly in a study of certain families 



