86 THE CONTROL OF LIFE 



ably tended to a depreciation of the importance of 

 nurture in general. 



(c) In the third place, when an appeal is made to 

 general facts so as to get away from the fallacy of arguing 

 from individual instances which happen to impress us, 

 the evidence warns us against attaching too much impor- 

 tance to nurture-effects. The statistical evidence fur- 

 nished by Professor Karl Pearson and his investigators at 

 the Galton Laboratory leads them to conclude that the 

 results of changes in ' nurture ' are of relatively small 

 importance compared with the results of intrinsic 

 variations in hereditary ' nature ' (including physique* 

 mentality, and habits) of the parents. We must con- 

 fess that it seems to us extraordinarily difficult in Man's 

 case to discriminate what is due to the inheritance 

 (granting in addition an average share of the appropriate 

 nurture that is indispensable if there is to be development 

 at all) from what is due to peculiarities of nurture 

 (granting again an average normal inheritance to work 

 upon). We are assured, however, that " the degree of 

 dependence of the child on the characters of its parentage 

 is ten times as intense as its degree of dependence on 

 the character of its home or uprearing." "It is five 

 to ten times as profitable for a child to be born of parents 

 of sound physique and of brisk, orderly mentality as 

 for a child to be born and nurtured in a good physical 

 environment." 



Let us consider the problem from a general biological 

 point of view. There are undoubtedly many cases in 

 which the developing organism is remarkably indifferent 



