240 REPRODUCTION, PUBERTY AND LONGEVITY. 



our previous tables we could give the average ages of the fathers 

 of these men without knowing anything about who they were. 



THE LONGEVITY AND BIRTH-RANKS OF GREAT MEN. 



To test this matter more fully I have calculated the length of 

 life of all of the great men of whom I have the birth-ranks, omitting 

 a few who came to violent deaths from one cause or another. The 

 result of this is shown in the following table : 



Relation of Birth-Rank to Length of Life. 



This table shows quite plainly that sons of old fathers live longer 

 than sons of young fathers, a fact that corresponds with what has 

 gone before and also with our previous observations in regard to 

 horses, cattle and seals. 



SELECTION ELIMINATED. 



There enters into this matter, however, a question of selection. 

 It may be argued that the sons of old men are necessarily the sons 

 of long lived parents, while sons of young men are the sons of both 

 long lived and short lived parents, and consequently cannot be 

 expected to live so long on an average. This contention has a 

 reasonable sound and is, in fact, more reasonable than many of the 

 attempts to explain by selection those phenomena generally attrib- 



