320 



THE TREND OF THE RACE 



to a class who marry comparatively late. It does not follow that 

 men attain unusual ability because their parents were relatively 

 mature at the time these men were born. The correlation between 

 ability and parental age is probably due mainly to the later mar- 

 riages of stocks of superior hereditary ability. 



Naturally if ability is a product of parental age we should 

 expect that the later born members of a family would most fre- 

 quently become distinguished. It is not difficult to amass a con- 

 siderable number of cases in which this is true. The evidence 

 compiled by Redfield, however, may be ofTset by the data gath- 

 ered by Ellis in the Study of British Genius to which reference has 

 already been made. The relation of frequency of genius to 

 parental age is given by Ellis as follows: 



Genius and Parental Age. 



The ages of the fathers of 100 cases of Galton's British men of 

 science were as follows: 



Age of father 20- 



Number i 



The average ages of Galton's, Ellis' and Yoder's list of fathers 

 (the latter based on 39 cases) were 36, 37.1, and 37.78 years 

 respectively. These differ but little from the averages of fathers 

 of men of professional and allied classes given by Ansell in 1874, 

 viz., 36.5. Geniuses are evidently not the product of senility to 

 any very considerable degree. Within the several families, so far 

 as our rather incomplete statistics go, actually more of them fall 

 into the ranks of the ist born (and hence the production of the 

 earlier years of the father's life) than in any subsequent birth 

 rank. 



Mention may be made of the studies of Professor A. Marro 



