RESEARCHES INTO ANTHROPOLOGICAL HEREDITY 



187 



Then we have another group, which besides this black pigment 

 in the back part of iris has a brownish pigment in the foremost strata. 

 The quantity of this pigment may vary very much. It may be found, 

 in so great a quantity that the eyes turn brown or brownish-black. Or 

 it may only be found in a narrow brown ring round the pupil. It 

 is sometimes found to radiate from the pupil, or it may appear as 

 dots spread all over the surface of iris. Where only found in very 

 small quantities it does not change the original colour of iris. It still 

 remains blue. If it is found in somewhat larger quantity the eyes get 

 an indescribable colour, greenish or grayish-green. This is of no con- 

 sequence in this connection. In order to make the survey easy and to 

 have greater numbers I counted at first only the two main types 

 of eyes. 



1. The eyes with a single layer of black pigment in the back part 

 of iris appearing always blue or gray. I call these eyes simple. 



2. The eyes which besides this pigment also contains a more or less 

 Ijrownish one, which eyes appear brown, green, grey, bluish- 

 brown or blue if the brownish pigment is to be found very scan- 

 tily. These eyes I call »doubly pigmented eyes» or for sake of 

 brevity »double eyes». All eyes are examined through a magni- 

 fying glass. 



I have examined 834 individuals in Selbu and Tydalen. If divided 

 in two groups according to age: children below the age of 16, and 

 grown up people older than 16, we get the following proportions. 



I had imagined that there would have been a much greater diffe- 

 rence between the groups of children and grown up people with regard 

 to »simple» and »double» eyes. In Selbu, for instance, there is scarcely 

 any difference in the eyes between the boys and the grown up men. 

 A further examination proves that the pigmentation of the eyes is 

 completed during the first 8 years. If examining the degree of pig- 

 mentation at every age, I find as follows: ^ 



* 1 indicates here the smaller degree of pigmentation, 2 the higher one. 



