124 NATURAL SELECTION AND 



tution : he does not give its " efficient cause," 

 he does not explain how the first germs of the 

 institution came into being, any more than an 

 evolutionist who uses the phrase " spontaneous, 

 variation/' 



In the case of the higher plants and animals, 

 an undoubted cause of variation is sex. It is 

 almost universally conceded that where two 

 parents are needed, instead of one, there is a 

 new combination of elements and a consequent 

 possibility of variation at every step in descent. 

 To produce the same apple we have to avoid 

 sexual reproduction ; seedlings mean the like- 

 lihood of new varieties. Direct action of the 

 environment is an undoubted cause of variation 

 in protozoa; whether it also affects species pro- 

 duced by sexual reproduction is the controversy 

 of the day among biologists. 1 (Of course it 

 affects all individuals^) 



Now does anything correspond to " sex " and 

 to " the direct action of the environment " in 

 the case of societies, institutions, customs ?' 

 The environment most certainly does act upon 

 races in determining their mode of life. Geo- 

 graphical conditions mountains, plains or sea. 

 1 See above, pp. 42, SS. 



