viii.] DISCUSSION OF THE DATA OF EYE COLOUR 145 



about only two-thirds of the grandparents, but this 

 will suffice for our purpose. The results are given in 

 Table 16. 



It will be observed that the distribution of eye-colour 

 among the grandparents of the hazel-eyed families is 

 nearly identical with that among the population at 

 large. But among the parents there is a notable 

 difference ; they have a decidedly larger percentage 

 of light eye-colour and a slightly smaller proportion 

 of dark, while the hazel element is nearly doubled. 

 A similar change is superadded in the children. The 

 total result in passing from generations III. to I., is that 

 the percentage of the light eyes is diminished from 

 60 or 61 to 45, therefore by one quarter of its original 

 amount, and that the percentage of the dark eyes is 

 diminished from 26 or 27 to 23, that is by about one- 

 eighth of its original amount, the hazel element in 

 either case absorbing the difference. It follows that 

 the chance of a light-eyed parent having hazel off- 

 spring, is about twice as great as that of a dark-eyed 

 parent. Consequently, since hazel is twice as likely to 

 be met with in any given light-eyed family as in a 

 given dark- eyed one, we may look upon two-thirds of 

 the hazel eyes as being fundamentally light, and one- 

 third of them as fundamentally dark. I shall allot 

 them rateably in that proportion between light and 

 dark, as nearly as may be without using fractions, and 

 so get rid of them. M. Alphonse de Candolle 1 has 



1 Heredity de la Conleur des Yeux dans l'Espece humaine," par 

 M. Alphonse de Candolle. " Arch. Sc. Phys. et Nat. Geneva," Aug. 1884, 

 3rd period, vol. xii. p. 97. 



