895 
On the Inheritance of Eye-colour wn Man. 
By C. C. Hurst. 
(Communicated by W. Bateson, F.R.S. Received May 7,—Read 
November 14, 1907.) 
The following notes on the inheritance of eye-colcur in man are based on 
material examined by the writer in the village of Burbage, Leicestershire. 
During the past three years, 139 pairs of parents and 683 of their offspring 
have been examined, with the following results :— 
Eye-colour in man depends almost wholly on the colour of the iris. The 
colour of the iris varies considerably in different families and often in 
different individuals of the same family. This variability is due partly to 
the presence or absence of different pigments on the anterior and posterior 
surfaces of the iris, and partly, in all probability, to actual differences in the 
structure of the iris. 
In the Report of the Anthropometric Committee of the British Association 
for 1880, the following statement concerning the nature of eye-colour in man 
is given by Mr. Charles Roberts (pp. 154 to 136) :-— 
“The iris, on which the colour of the eye depends, is a thin membranous 
structure, composed of unstriped muscular fibres, nerves, and blood-vessels, 
held together by a delicate network of fibrous tissue. On the inner surface 
of this membrane there is a layer of dark purple pigment called the 
wvea ... and in brown eyes there is an additional layer of yellow (and, 
perhaps, brown-red) pigment on its outer surface also, and in some instances 
there is a deposit of pigment amongst the fibrous structures. In the albino 
where the pigment is entirely absent from both surfaces of the iris, the 
bright red blood is seen through the semi-transparent fibrous tissues of a 
pink colour; and in blue eyes, where the outer layer of pigment is wanting, 
the various shades are due to the dark inner layer of pigment—the weea— 
showing through fibrous structures of different densities or degrees of 
opacity. 
“The eyes of new-born infants . . . are dark blue, in consequence of the 
greater delicacy and transparency of the fibrous portion of the iris; and as 
these tissues become thickened by use, and by advancing age, the lighter 
shades of blue and, finally, grey are produced, the grey, indeed, being chiefly 
due to the colour of the fibrous tissues themselves. In grey eyes, moreover, 
we see the first appearance of the superficial layer of yellow pigment in the 
