Queen Elizabeth II's husband, Prince Philip, was hospitalized with a chest infection and is undergoing a series of tests, Buckingham Palace said Friday. Philip, 86, suffered from a bad cold that worsened in recent days, palace officials said. Doctors at London's King Edward VII hospital were trying to determine the cause of the infection. Prince Philip was strong enough to walk into the hospital without assistance and was able to read and answer letters from his bed, a spokeswoman said. He traveled to the hospital by private car, not ambulance, another Buckingham Palace spokesman said.