DALLAS -- A tiny video camera on his collar, Barney offered a dog-level holiday tour of the White House in 2002 as he shuffled from room to room and menaced the Christmas tree.The video starring President George W. Bush's black Scottish terrier drew 24 million online tourists the first day.Bush and his wife, Laura, said Friday that their famous 12-year-old pooch died after suffering from lymphatic cancer."Barney was by my side during our eight years in the White House," Bush said. "He never discussed politics and was always a faithful friend. Laura and I will miss our pal."Barney politely greeted heads of state, queens and prime ministers but "guarded the South Lawn entrance of the White House as if he were a Secret Service agent," Bush said.Burial is planned at the former president's ranch near Waco.