Mandela's health improving but condition still 'serious' JOHANNESBURG (Reuters) - Former South African President and anti-apartheid leader Nelson Mandela continues to recover from a lung infection but his condition remains serious, the South African government said on Thursday. President Jacob Zuma visited Madiba, the clan name by which 94-year-old Mandela is popularly known, in the Pretoria hospital to which he was admitted in a "serious but stable" condition on Saturday, a statement said. "We continue to appeal to people to keep Madiba in their prayers and wish him a speedy recovery," Zuma said. Mandela's hospitalization is his fourth since December and has reinforced a creeping realization among South Africa's 53 million people that they will one day have to say goodbye to their first black president. During his time in hospital, the principal architect of the post-apartheid "Rainbow Nation" has also received visits from members of his family, including his wife Graca Machel and former wife Winnie Madikizela-Mandela. Mandela has a history of lung problems dating back to his time at the windswept Robben Island prison camp near Cape Town. He was released in 1990 after 27 years behind bars and went on to serve as president from 1994 to 1999. Reporting by Ed Cropley; Editing by Pravin Char