471 
1911-12.] On Inheritance of Hair and Eye Colour. 
One other point requires to be considered. In this paper fair-haired 
and medium-haired persons have been classed together, and the question 
arises as to the effect this may have on the relative proportions of mixed 
and dark eyes, as it might well be that a mixed grey and chocolate eye and 
a mixed bine and chocolate eye would impress an observer differently. 
Personal observation renders it probable that the latter is more often 
classed as dark, and the figures bear out this observation. The proportions 
are shown in the accompanying table 
Table VII. 
Ratio of 
Fair to 
Medium 
Hair. 
Light Hair. 
Ratio. 
Dark Hair. 
Ratio. 
Black 
Hair. 
Ratio. 
Mixed 
Eyes. 
Dark 
Eyes. 
Mixed 
Eyes. 
Dark 
Eyes. 
Mixed 
Eyes. 
Dark 
Eyes. 
>1-2 
5-8 
5'1 
1*13 
5-4 
11-5 
•47 
•95 
2-60 
•37 
>1<1'2 
6-9 
6-5 
1-06 
5-6 
11*2 
•50 
•84 
2*24 
•37 
<1 
6*2 
6-8 
•91 
5-7 
11 3 
•50 
•74 
2-91 
•25 
It is to be noted that the ratio of mixed to dark eyes tends in the 
groups of light hair and black hair to decrease with the decrease of light 
hair and to remain constant in the group of dark hair. From such facts 
no certain inferences can be drawn, but the suggestion is that a mixed blue 
and chocolate eye is somewhat darker on the average than a mixed grey 
and chocolate eye. 
Conclusions. 
(1) Many of Dr Beddoe’s populations are stable in a Mendelian sense. 
Though this does not necessarily imply that the theory as stated by Mendel 
is the only explanation of the arithmetical proportions found, any other 
theory claiming to explain the facts of heredity must also explain these 
relative proportions. 
(2) That linkage between hair colour and eye colour exists. The 
coupling factor is more likely to be 9 than 7, and therefore does not agree 
with the present Mendelian theory. It is quite possibly to be explained 
on the analogy of chemical equilibrium. 
(3) That it is possible that the colour of the hair has, in addition to this, 
some other effect in altering the colour of the eyes ; but the evidence is not 
sufficient to prove this, and it may be only due to the fact that dark eye- 
lashes tend to lend a darker appearance to eyes than would be found 
justified on a more careful examination. 
