46 



HEREDITY AND EUGENICS 



their eyes, and one of the latter married a blue-eyed 

 man and had six children, all blue-e3^ed. This case 

 is thought to be explained b}" assuming that one of the 

 grandparents was genot3'picalh^* brown-eyed but had 

 a " pigment restrictive disposition " which made him 

 or her phenotypically (that is, visibty) blue-eyed. 

 The brown-eyed daughter having blue-eyed children 

 is explained by sex-linked inheritance. It is shown 

 from other evidence that pigment-inhibiting factors 

 ma}" be accompanied by abnormalities in vision, 

 but the interpretations in this part of the paper are 

 not always convincing. 



TABLE I. 

 Inheritance of Eye Colour (Winge). 



Perhaps the most interesting results of Winge 

 concern the sex-linked inheritance of eye colour. 

 The statement that there are more brown-eyed 

 women than men was borne out by statistics of 

 300,000 school children, collected by S. Hansen. 

 Similar results have been obtained by others. Winge 

 shows the fact of sex-linkage by giving the results 

 of marriages in which the parents had different e^^e 

 colour. These are appended in the following tables : 



* That is, in inherited germinal constitution. 



