A Weymouth man who allegedly stabbed a taxi driver in Whitman on Saturday was arraigned in his bed at a Brockton hospital Monday, authorities said. Christopher Herbert, 21, was taken into custody Saturday on a warrant that charged him with attempted murder, assault and battery with a dangerous weapon, mayhem, and armed robbery. Early Saturday, the 56-year-old male cabdriver was found near Pine Street and Hutchinson Terrace. He sustained serious injuries, police said, including cuts to his head and bruises on his face, and injuries to his eyes. He was treated at South Shore Hospital and later discharged, police said.