When he was too old (at 41) to enlist in the Army at the onset of World War I, Wood volunteered in the hospital wards and his exposure to the gruesome injuries inflicted by the new war's weapons eventually led him to open a special clinic: the Masks for Facial Disfigurement Department, located in the Third London General Hospital, Wandsworth. Instead of the rubber masks used conventionally, Wood constructed masks of thin metal, sculpted to match the portraits of the men in their pre-war normality. Just as had been happening with soldiers operated upon with the recent advances in plastic surgery, Wood's masks provided each with a renewed self-confidence, even self-respect, though they often proved uncomfortable. Face wounds were known to be the most devastating. By hiding the wounds behind the mask, the young men were able to return to relationships with their families and friends.