844 HEREDITY AND SELECTION IN SOCIOLOGY 



to attain maturity and reproduce themselves, constitute an 

 ever growing menace to race progress. For it must be borne in 

 mind that these weak individuals can only multiply themselves 

 at the expense of the strong and healthy, space and food being 

 necessarily limited. Thus, not only is a quantity of life arti- 

 ficially produced, which is more or less worthless to the indi- 

 viduals possessing it, but a quantity of useful life is actually 

 prevented thereby from coming into being. The life of the 

 weakling or of the invalid, who exists thanks only to the progress 

 of hygiene, is a life which is poor in vitality, consequently a 

 life incapable of fulfilling the elementary law of all life — that 

 of expansion ; for only the life which has an overflowing rich- 

 ness of vitality can hope to expand and to live fully in the 

 best sense of the term. By the multiplication of weaklings 

 the vitaHty and robustness of the entire race is impaired, an 

 amount of sufiering is engendered, and an amount of happiness 

 — which has health and vitality as its primary condition — is 

 excluded. 



It has been very truly remarked that the tubercle bacillus is a 

 friend of the human species, for it attacks no healthy man or 

 woman, but only the feeble.^ It is extremely probable that 

 there is no one in the world — at least, in those countries where 

 the bacillus exists — who has not, at some period or another of 

 his life, had the deadly bacillus in the mouth ; but the tuber- 

 culosis bacillus is deadly only for those whose constitution is 

 weak or diseased. A healthy person affords no soil for the 

 bacillus, which will be devoured by the phagocytes in the blood- 

 stream, or otherwise destroyed. Thus, tuberculosis may be 

 regarded, in a certain sense, as a selective agency par excellence 

 which eliminates the unfit members of the race, whose constitu- 

 tion is pre-eminently predisposed to the cultivation of the 

 bacillus. Children bom of tuberculous parents are especially 

 predisposed to this disease ; and, as we have seen, syphilis may 

 ' Haycraft, Darioinism and Race Progress, p. 57. 



