Shocking as it may seem, U.S. government doctors once thought it was fine to experiment on disabled people and prison inmates. Such experiments included giving hepatitis to mental patients in Connecticut, squirting a pandemic flu virus up the noses of prisoners in Maryland, and injecting cancer cells into chronically ill people at a New York hospital. Much of this horrific history is 40 to 80 years old, but it is the backdrop for a meeting in Washington this week by a presidential bioethics commission. The meeting was triggered by the government's apology last fall for federal doctors infecting prisoners and mental patients in Guatemala with syphilis 65 years ago. U.S. officials also acknowledged there had been dozens of similar experiments in the United States. Inevitably, they will be compared to the well-known Tuskegee syphilis study. In that episode, U.S. health officials tracked 600 black men in Alabama who already had syphilis but didn't give them adequate treatment even after penicillin became available. Though people in the studies were usually described as volunteers, historians and ethicists have questioned how well these people understood what was to be done to them and why, or whether they were coerced. In the last 15 years, two international studies sparked outrage. U.S.-funded doctors failed to give the AIDS drug AZT to all the HIV-infected pregnant women in a study in Uganda even though it would have protected their newborns. The other study, by Pfizer Inc., gave an antibiotic named Trovan to children with meningitis in Nigeria, although there were doubts about its effectiveness. Critics blamed the experiment for the deaths of 11 children and the disabling of scores of others. Pfizer settled a lawsuit with Nigerian officials for $75 million but admitted no wrongdoing.