In the fall of 1932, the fliers began appearing around Macon County, Ala., promising colored people special treatment for bad blood. Free Blood Test; Free Treatment, By County Health Department and Government Doctors, the black and white signs said. YOU MAY FEEL WELL AND STILL HAVE BAD BLOOD. COME AND BRING ALL YOUR FAMILY. Hundreds of men all black and many of them poor signed up. What the signs never told them was they would become part of the Tuskegee Study of Untreated Syphilis in the Negro Male, a secret experiment conducted by the U.S. Public Health Service to study the progression of the deadly venereal disease without treatment. The study recruited 600 black men, of which 399 were diagnosed with syphilis and 201 were a control group without the disease. The researchers never obtained informed consent from the men and never told the men with syphilis that they were not being treated but were simply being watched until they died and their bodies examined for ravages of the disease. Initially, when the study began, treatment for syphilis was not effective, often dangerous and fatal. But even after penicillin was discovered and used as a treatment for the disease, the men in the Tuskegee study were not offered the antibiotic. Although originally projected to last six months, the study extended for 40 years. Local physicians asked to assist with study and not to treat men, the Centers for Disease Control reported in a timeline of the experiment.