SELECTION AND TRAINING 439 



develop^ we may alter the kind and amount of STIMULUS they 

 receive. Thus, if we wish to increase the size and strength of 

 Englishmen, we must breed from individuals who grow big and 

 strong under present conditions, or we must try so to improve the 

 surroundings that, with the same average capacity for growth, 

 individuals will grow bigger and stronger than they do at present. 



720. Human selective breeding presents obvious difficulties. 

 It is possible that in a future not very remote some control will be 

 exercised by law or an enlightened public opinion over the multi- 

 plication of particularly undesirable types, for example, imbeciles 

 and people very susceptible to tuberculosis or the charm of alcohol. 

 But selection with a view, not merely to prevent marked deteriora- 

 tion, but to raise the general standard of the race is at present an 

 impracticable dream. Moreover, even were such selection practical 

 it would have to be undertaken with the greatest caution. Mis- 

 taken notions as to what characters are desirable in human beings 

 might entail disastrous and not easily remedied consequences. 

 That mistakes in human breeding might easily be made is evident 

 from the fact that many races, including our own, practise mutila- 

 tions as a means of improving beauty, and that the majority of the 

 people of all races greatly admire and strive to perpetuate a very 

 real kind of stupidity. 1 On the other hand, it is comparatively easy 

 both to alter the conditions under which development occurs, and, 

 even in the very next generation, to remedy altogether any 

 mistakes that might be made. Clearly, therefore, it is better to 

 exhaust the possibilities which may be achieved by such means as 

 improved food, housing, and physical and mental training, before 

 we attempt to tread the difficult and dangerous path of selective 

 breeding. 



721. It is important, therefore, to ascertain as precisely as 

 possible what characters in human beings it is practicable to 

 improve by altering the environment, to what extent they may be 

 thus improved, and by what means the improvement may be 

 brought about. Only so shall we reach that bed-rock of fact and 

 clear understanding without which the discussion of such great 

 problems as physical and mental deterioration, alcoholism, public 

 health, social and moral reform, education, and the like, is vague 

 and unprofitable. I am not aware that any very thorough-going 

 endeavour to analyse the characters of living beings, especially 

 human beings any endeavour to separate the ' inborn ' from the 

 ' acquired ' has been attempted hitherto. I say especially human 



1 See 805 et seq. 



