1 44 DAR WIN ISM AND RA CE PROGRESS. 



those who occupy what in the world's estimation are 

 high positions, and this implies diminished fertility 

 on the part of the women. We should expect from 

 common observation that the )'ounger women would 

 be more prolific, and this is borne out by exact 

 statistical observation. Matthews Duncan 1 concludes 

 that women who marry from twenty to twenty-four 

 are the most prolific, and that the only period which 

 at all rivals this is the five years from fifteen to nine- 

 teen inclusive, and that women married later in life 

 than twenty-four are distinctly less prolific. 



Lower Class Marriages are the Most Prolific. 



Not only do the wives of the working classes pro- 

 duce individually more children than those of the 

 professional classes, but, owing to these earlier 

 marriages, generations succeed each other with greater 

 rapidity. In order to realise how soon a slight ad- 

 vantage like this tells upon the composition of the 

 race, we will suppose for the nonce that the labourer's 

 wife A marries at twenty-three, and the lawyer's wife 

 B marries at twenty-six, and that they have the same 

 number of children, in each case four. In the case of 

 A the population will double, say roughly, every twenty- 

 seven years, and in the case of B every thirty years, 

 allowing in each case four years for the birth of the 



1 "Fecundity, Fertility, and Sterility," second edition, 

 chapter xiv. 



