Why Are the Complexions of Some People Light and Others Dark?
This difference in the complexions of people is due to the varying amounts of pigment or coloring material in the cells of which the skins of all animals is made up. Very light people have very little pigment; very dark people, those with dark eyes and black hair, have a great deal of this coloring material in their cells. A great many people are neither light or very dark. They have less than the dark-complexioned people and more than the light-complexioned people. When the hair turns gray it is because the pigment has disappeared. As this is due to the loss of this coloring material, dark-complexioned people turn gray sooner than light-complexioned people. The structure of the skin showing how these cells are made in layers can be seen by examining the skin with a microscope.