Wolf Blood 1925

The oldest remaining werewolf movie. A silent feature. Dick Bannister is the new field boss of the Ford Logging Company, a Canadian logging-crew during a time when conflicts with the powerful Consolidated Lumber Company, a bitter rival company, have turned bloody, like a private war. His boss, Miss Edith Ford, comes to inspect the lumberjack camp, bringing her doctor fiancé with her. Dick is attacked by his rivals and left for dead. His loss of blood is so great that he needs a transfusion, but no human will volunteer, so the surgeon uses a wolf as a source of the blood. Afterwards, Dick begins having dreams where he runs with a pack of phantom wolves, and the rival loggers get killed by wolves. Soon, these facts have spread through the camp and most of the lumberjacks decide that Dick is a werewolf. (taken from Wikipedia)