XIV 
COLOURS OF MAMMALS 
289 
dark races of mankind owe the colour of their skin 
to a black pigment deposited in the deeper layers of 
the epidermis—a pigment which is practically absent 
in white-skinned people. ‘The varying tints of the 
hair are also due to the varying amounts of the same 
dark pigment deposited in it. That differences in 
skin-colour often correspond to profound racial dif¬ 
ferences is familiar in a rough way to every one, but 
there are some interesting facts which tend to show 
that even apparently slight differences in intensity of 
pigmentation may correspond to relatively vast con¬ 
stitutional differences. 
We propose to confine our study of the question 
to variations in the colour of the hair and eyes in 
the white-skinned peoples, where the data are most 
easily obtainable. The first point of interest is the 
curious fact shown by Galton’s statistical researches 
that among ourselves there is little tendency for the 
dark and fair strains to mingle, “ to be swamped by 
intercrossing,” in the current phrase. The children 
of parents of whom one is dark and the other fair 
will as a rule either have dark or light eyes, only 
rarely will they have eyes of medium colour (Natural 
Inheritance , p. 139). In Mr. Bateson’s words, the 
variations are discontinuous. 
The next point is that, according to Dr. Beddoe’s 
prolonged observations, “ the colour of the hair is so 
nearly permanent in races of men as to be fairly trust¬ 
worthy evidence in the matter of ethnical descent, and 
nearly as much may be said for the colour of the iris ” 
(The Races of Britain , p. 269). His observations 
further show that the dark-haired people correspond 
roughly to the Gaelic and Iberian stocks, while the fair- 
U 
