The number is somehow irrelevant. Like most people, their limited knowledge of History comes from the crap they watched on tv That being said it's reported to be 600 https://en.wikipedia.org/wiki/Tuskegee_Syphilis_Study#Study_participants The Public Health Service started the study in 1932 in collaboration with Tuskegee University (then the Tuskegee Institute), a historically black college in Alabama. In the study, investigators enrolled a total of 600 impoverished African-American sharecroppers from Macon County, Alabama.[6] Of these men, 399 had latent syphilis, with a control group of 201 men who were not infected.[5] As an incentive for participation in the study, the men were promised free medical care, but were deceived by the PHS, who never informed subjects of their diagnosis[7][8][9][10] and disguised placebos, ineffective methods, and diagnostic procedures as treatment.[11] The men were initially told that the "study" was only going to last six months, but it was extended to 40 years.[5] After funding for treatment was lost, the study was continued without informing the men that they would never be treated. None of the infected men was treated with penicillin despite the fact that, by 1947, the antibiotic was widely available and had become the standard treatment for syphilis.[12] The study continued, under numerous Public Health Service supervisors, until 1972, when a leak to the press resulted in its termination on November 16 of that year.[13] By then, 28 patients had died directly from syphilis, 100 died from complications related to syphilis, 40 of the patients' wives were infected with syphilis, and 19 children were born with congenital syphilis.[14]