universal, there would be fifty per cent more Beauty in the world
after a single generation.
In the centre of the white sclerotic is the membrane which gives
the eyes their characteristic variations of colour,—the iris or rainbow
curtain. If we look at an eye from a distance of a few paces, it
seems to have some one definite colour, as brown or blue. But on
closer examination we see that there are always several hues in
each iris. The colour of the iris is due to the presence of small
pigment granules in its interior layer. These granules are always
brown, in blue and gray as well as in brown eyes; and the greater
their number and thickness, the darker is the colour of the iris. Blue
eyes are caused by the presence, in front of the pigment-layer, of a
thin, almost colourless membrane, which absorbs all the rays of light
except the blue, which it reflects, and thus causes the translucent
iris to appear of that colour.
The Instructions de la Société d’Anthropologie, says Dr. Topinard,
"recognise four shades of colour,—brown, green, blue, and gray;
each having five tones—the very dark, the dark, the intermediate,
the light, and the very light. The expression “brown” does not mean
pure brown; it is rather a reddish, a yellowish, or a greenish brown,
corresponding with the chestnut or auburn colour, the hazel and the
sandy, made use of by the English. The gray, too, is not pure; it is,
strictly speaking, a violet more or less mixed with black and white."
“The negro, in spite of his name, is not black but deep brown,” as
Mr. Tylor remarks; and what is true of his complexion is also true of
his eyes; “what are popularly called black eyes are far from having
the iris really black like the pupil; eyes described as black are
commonly of the deepest shades of brown or violet.”
The pupil, however, is always jetblack, not only in negroes, but in
all races. For the pupil is simply a round opening in the centre of the
iris which allows us to see clear through the lens and watery
substance of the eyeball to the black pigment which lines its inside
surface. The iris, in truth, is nothing but a muscular curtain for
regulating the size of the pupil, and thus determining how much
light shall be admitted into the interior of the eye. When the light is
bright and glaring, a little of it suffices for vision, hence the iris