IIEUEDITY AND "I'lIYSICAL DI!:GENKKATI()N" lO.'J 



selective process is duini,^ all that any soluclivc 

 process can do. On the contrary, we must recognise 

 that certain modern doctrines and practices do tend ^ 

 towards the most unwise and disastrous limitation 

 of the action of natural selection. It is not well 

 that civilisation should interfere with natural selec- 

 tion, and artificially facilitate the reproduction of 

 those attticted with certain forms of vice or mental 

 or physical disease. Furthermore, it is our duty, 

 having recognised the potency of heredity, and 

 therefore the importance of the principle of selection, 

 to aid its action, and extend it in accordance with 

 our ideals.- If artificial selection is worth while 

 in the case of race-horses, it is worth while in the 

 case of man. 



CHAPTER Xlli 



HEREDITY AND DISEASE 



The title of this chapter covers several subjects 

 which are not closely related to one another, hut 

 which may be conveniently dealt with under this 

 heading. The first of these is of little importance 

 in connection with the theory of heredity, but others 

 are of high theoretical interest. 



The inheritance of disease is a subject on whieh 

 our opinions have lately undergone a profound 

 revolution. This is indeed to be expected, if wo 

 remember that it is but a few decades since wo 



1 See the chapter, " Socialism," in the volume •' Sociolofry." 

 « See the chapter, " The Future Evolution of Man," in the volume 

 " Organic Evolution." 



