Science: Skin Colors

Anatomists have long held that white skins are tinted by three pigments: melanin, a black chemical; hemoglobin, a reddish substance which colors the blood; oxyhemoglobin, a form of hemoglobin in combination with oxygen. They also believed that Negroes and Orientals are darker than Caucasians partly because of the presence of some special, unknown pigment in their skins.

To Anatomist Edward Allen Edwards of Harvard and Physicist Seibert Quimby Duntley of Massachusetts Institute of Technology, these theories were only skin-deep. Instead of the naked eye they used a spectrophotometer, a photoelectric device which analyzes skin color by measuring its capacity to reflect light at each separate wave length of the spectrum. Painstakingly they analyzed the entire skin surface of three white men, three white women, a Japanese, a Hindu, a Negro and a mulatto. Last week in one of the most thorough analyses of skin color ever published, Drs. Edwards and Duntley announced: 1) two pigments hitherto unknown in the skin are involved in skin color; 2) skins of all races are chemically similar.

Besides melanin and both hemoglobins, said the scientists, a yellow pigment, carotene, is found in the upper layers of all human skin. Carotene, a component of sweet potatoes, corn, butter, carrots and milk, is responsible for the yellowish palms, soles and eyelids of white persons. But although a white person may acquire a pale yellow tinge all over by eating enormous amounts of carotene, carotene is not what makes Orientals yellow. Normal persons of all races have roughly the same amounts of carotene.

What does make darker races darker is a larger proportion of fine, microscopic granules of black melanin scattered throughout the upper layers of their skin. In upper skin layers melanin disintegrates, turns into melanoid, the other pigment discovered in the skin by Drs. Edwards and Duntley. Everybody has some melanin and melanoid in his skin, but blonds have less than brunets, white women less than white men, white races less than dark races.

"The melanin content increased in the subjects studied in the following order: Japanese, Hindu, mulatto and Negro," said the scientists. "Our studies do not support the theories that the pigmentation of the skin in the dark races is caused by pigments which are not found in the white race."