PROFESSOR K. PEARSON AND DR, A. LEE ON 
1 08 
general tendency of a series rather than pick out single differences for special 
consideration. If we do this we shall still find that remarkable results flow 
from our Tables VII. and VIII., most of which seem hitherto to have escaped 
attention. 
I return now to the special topic of the present section, the mean eye-colour, after this 
lengthy—if needful—digression on the probable error of the data given in our tables. 
We may, I think, safely draw the following conclusions :— 
(a.) Man has a mean eye-colour very substantially lighter than that of woman. 
If we compare the mean eye-colour of father with mother, of son with daughter, 
of brother with sister, of grandfather with mother, of uncle with aunt, of grandson 
with granddaughter, of nephew with niece, we have the same result—man is distinctly 
lighter eyed than woman. 
( b.) There appears to be a secular change taking place in eye-colour , but this is 
more marked and definite in the man than in the woman. 
Thus we have the following mean values for y in classes, which must roughly 
Grandmother . . '8757 1 0 c->o 
> , 8523 
Mother .... -8290 J 
Daughter. . . . 7524 I „„. 
° > ‘8016 
Granddaughter. . '8508 J 
Another comparison may be made by noting that grandsons are darker than 
grandfathers, sons than fathers, nephews than uncles. Similarly, granddaughters are 
lighter than grandmothers, daughters than mothers, but nieces are not lighter than 
aunts, as we might have expected. Thus, while the records show a definite darkening 
of the eyes of men, there appears to be a certain but less sensible lightening of the 
eyes of women. Again, the younger generations are much closer in eye-colour than 
the older generations. The difference in eye-colour between grandsons and grand¬ 
daughters, sons and daughters, nephews and nieces is only about 15 per cent, of the 
grey blue-green range, but for fathers and mothers it is 30 per cent., and for grand¬ 
fathers and grandmothers 50 per cent. 
When we realise that difference in eye-colour appears to be a sexual character, the 
true explanation of this secular change in eye-colour becomes still more obscure. 
If the lighter eye-colour of the older generation be due to an effect of old age, why 
is it conspicuous only in the male and not in the female ? Why is the mother sensibly 
darker than the daughter, but the father sensibly lighter than the son ? 
Further, supposing light eyes much commoner among our grandfathers than among 
their grandsons, and dark eyes among our grandmothers than among their grand¬ 
daughters, we cannot attribute the great approach in eye-colour to a blending of the 
parental characters, for, as we shall see later, eye-colour does not seem to blend, it is 
rather an exclusive character. We should, therefore, be thrown back on prepotency 
represent successive generations :— 
Grandfather. . . ‘3658 
Father .... '5241 J 
Son.'5929 
Grandson. . . . 7039 
•4449 
•6484 
