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 offset 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. 
Age of Father 20 |20-24|25-29| 30-34) 35—39| 49-44) 45-49 |50- 54/5559 
No. of fathers...} 2 9 145 | 8t | 59 | 44 | 30 | 13 8 
Percentage..... 6 3 |15 | 27 | 19 | 14 | 10 4 2 
The ages of the fathers of 100 cases of Galton’s British men of 
science were as follows: 
Age of father............. 20- 25- 30- 35- 40- 45- 50- 
NUM DER ansvia sauce se) sawn I 15 34 22 17 7 4 
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 rst 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 
