CHAPTER V 



CONTROL OF HEREDITY: EUGENICS 

 It is the aim of science to interpret phe- 

 nomena and as far as possible to control 

 them. To what extent is it possible to control 

 heredity and thus to improve the race, as well 

 as the individual? 



A. DOMESTIC ANIMALS AND CULTIVATED 

 PLANTS 



The history of domesticated animals and 

 cultivated plants shows that it is possible to 

 control or rather guide phenomena of he- 

 redity and evolution. Very many species of 

 wild animals have been tamed by man but 

 only about 40 species may be classed as domes- 

 ticated. DeCandolle recognized 247 species 

 of cultivated food plants, 193 of which still 

 exist in the wild state.* In a number of in- 

 stances the wild stocks from which these do- 



* Bailey says that more than 20,000 kinds of plants in 

 cultivation are described in the "Standard Cyclopedia of 

 Horticulture," although not nearly all of these species are 

 domesticated. 



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