XXIX 

 THE FEEBLE-MINDED 



A CONSIDER ABLE proportion of the young which 

 are produced as a new generation of either plants 

 or animals are not merely unlike their parents in some 

 small particulars of colour, proportion, activity, and so on, 

 but are, as compared with the normal or usual standard 

 of the species, " defective " ; that is to say, they are want- 

 ing in some organ or part, as though maimed, or by some 

 cause restricted or reduced in regard to that part. This 

 occurs in human beings, and in domesticated animals 

 more obviously than in wild animals and plants, for two 

 reasons : firstly, because in wild conditions the defective 

 young die off very early in the struggle for existence and 

 so escape human observation ; whereas man protects his 

 own " defective " young, and often, also, those of domesti- 

 cated animals, so that they are allowed to " grow up " more 

 or less ; secondly, such defective structure appearing at 

 birth, and therefore called " congenital," is carried on by 

 heredity, more or less completely, should the defective 

 animal or plant be allowed to breed. Such breeding of 

 defective individuals is prevented in wild nature by their 

 early destruction ; their defects cause their early death by 

 unfitting them for the competition and struggle which are 

 in natural conditions rigidly severe. Only a few survive 

 among the many thousands of each species born into 



