James Brown, 72, an actor best known as Lt. Rip Masters in the 1950s television series "The Adventures of Rin Tin Tin," died Saturday of cancer at his Los Angeles home. He began his acting career in the 1940s and appeared in more than 40 films, including "Going My Way," "Air Force," "The Fabulous Texan" and "The Charge at Feather River." He also appeared in many television shows, including "Dallas," "Murder She Wrote," "Route 66" and "Gunsmoke." "The Adventures of Rin Tin Tin" featured a German shepherd and a young boy, Rusty, as his sidekick. Mr. Brown's character was a father figure to Rusty, who was on his own with his canine pal at a cavalry outpost in the Old West.