For forty years between 1932 – 1972, the U.S. Public Health Service (PHS) conducted an experiment on 399 black men in the late stages of syphilis. The black men, for the most part illiterate sharecroppers from one of the poorest counties in Alabama, were never told what disease they were suffering from or of its seriousness. Informed that they were being treated for bad blood their doctors had no intention of curing them of syphilis at all. The data for the experiment was to be collected from autopsies of the men, and they were thus deliberately left to degenerate under the final stage, ravages of tertiary syphilis—which can include

• tumors,
• heart disease,
• paralysis,
• blindness,
• insanity,
• and death.

“As I see it,” one of the doctors involved explained, we have no further interest in these patients until they die.

…
By the end of the experiment:

• 28 of the men had died directly of syphilis,
• 100 were dead of related complications,
• 40 of their wives had been infected,
• and 19 of their children had been born with congenital syphilis.

How had these men been induced to endure a fatal disease in the name of science? To persuade the community to support the bad experiment, one of the original doctors admitted it “was necessary to carry on this study under the guise of a demonstration and provide treatment.” At first, the men were prescribed the syphilis remedies of the day—bismuth, neoarsphenamine, and mercury—but in such small amounts that only 3 percent showed any improvement.

…
One of the most chilling aspects of this experiment was how zealously the PHS kept these men from receiving real treatment. When several nationwide campaigns to eradicate venereal disease came to Macon County, the men were prevented from participating. Even when penicillin (antibiotics) was discovered in the 1940s—the first real cure for syphilis—the Tuskegee men were deliberately denied the good medication! (more at infoplease.com)