Betty Shabazz, the widow of Malcolm X who was badly burned in a fire that police believe her 12-year-old grandson set, underwent a fourth surgical procedure to remove more charred skin, hospital officials said. The operation was successful, said Rita Connelly, nursing supervisor at Jacobi Medical Center. The hospital said 72% of Shabazz's burned tissue has been removed, and her next operation is scheduled Tuesday. Doctors are replacing her burned skin with artificial skin to prevent infection and fluid loss. Shabazz, 61, was burned over more than 80% of her body in a fire in her Yonkers, N.Y., apartment June 1. A blood drive for her is planned today, said organizer Elinor Tatum, associate publisher of the Amsterdam News.