Stamped from the Beginning: The Definitive History of Racist Ideas in America by Ibram X. Kendi:
Physical anthropology, a discipline studying biological racial distinctions, had split off from cultural anthropology, which studed cultural distinctions. Boas was at the helm of cultural anthropology; the anthropologists at the helm of physical anthropology were Earnest A. Hooton and Carleton S. Coon at Harvard. In 1931, Hooton authored Up from the Ape, which became a staple in physical anthropology courses over the next few decades. “Physical characteristics,” Hooton explained, “which determine race are associated, in the main, with specific intangible and non-measurable but nevertheless real and important, temperamental and mental variations.
Many of Hooton’s students entered the health-care sector, where segregationist ideas of biological races were rampant, and where workers were still treating diseases differently by race. Syphilis harmed Blacks much more than it did Whites, argued syphilis “expert” Thomas Murrell in Journal of the American Medical Association in 1910. But this theory had never been definitively proven. So in 1932, the US Public Health Service began its “Study of Syphilis in the Untreated Negro Male.” Government researchers promised free medical care to six hundred syphilis-infected sharecroppers around Tuskegee, Alabama. They secretly withheld treatment to these men and waited for their deaths, so they could perform autopsies. Researchers wanted to confirm their hypothesis that syphilis damaged the neurological systems of Whites, while bypassing Blacks “underdeveloped” brains and damaging their cardiovascular systems instead. The study was not halted until the press exposed it in 1972.