SELECTIVE BIRTH-RATE 151 



tual activity in Europe are represented in England 

 by the revival of arts and learning in the thirteenth 

 century, and with the achievements of the reigns of 

 Elizabeth and Victoria. 



The two latter times of development are well shown 

 by the increases in the numbers of men of sufficient 

 eminence to be included in the Dictionary of National 

 Biography. While the fourteenth and fifteenth cen- 

 turies show the nearly equal numbers of 678 and 

 659 respectively, the sixteenth leaps up with 2138. 

 The seventeenth and eighteenth are again nearly on 

 a level with 5674 and 5789 names, although in 

 the eighteenth the population begins to rise, but the 

 nineteenth gives a total of 12,608. This last 

 number is probably swollen both by the great in- 

 crease in the number of the people and by the 

 tendency to exaggerate contemporary achievement, as 

 well as by the multiplicity of new callings which have 

 given scope for fresh varieties of specialized ability, 

 but it seems too large to be attributed entirely to these 

 causes. 



However we explain the facts before us, facts they 

 certainly are, and are borne witness to by the unbiased 

 record of the great English Biographical Dictionary, 

 Something has been at work to produce definite fluctu- 

 ations of ability throughout the ages of our history. 

 The simplest and most direct cause, a variation in the 

 number of able people actually born, may well be con- 

 sidered before other agents are called in to account for 

 the phenomenon. 



In the thirteenth century, we see the settlement of 

 Europe into its constituent kingdoms after the turmoil 



