text:  Odette Youssef, NPR News. For nearly 40 years, the U.S. Public Health Service left hundreds of black men in Tuskegee, Alabama, untreated for syphilis. It was part of a study that was only stopped after whistleblower Peter Buxton revealed the unethical and racist experiment to the press. Buxton died of Alzheimer's disease in California. He was 86. NPR's Debbie Elliott joins us now to talk about the significance of his revelation. Hi, Debbie. Hi there, Anna.