James Henry McCallum (1893-1984) was an American missionary who helped organize the University of Nanjing Hospital, the International Committee, and the Safety Zone during the Japanese invasion of Nanjing in 1937-1938.
"After the city was captured by the Japanese, McCallum endeavored to search for food, vegetable, meat, fuel and other supplies for the patient-crowded University of Nanjing Hospital, which proved to be no easy task in war-torn Nanjing. He was always seen hurrying from one place to another in the hospital ambulance. He even had to act as a bodyguard to discharged patients to assure their journey home was safe. Once news arrived that an atrocity victim was trapped in a corner of the city, McCallum would drive the ambulance to bring that wounded person to the hospital. He witnessed or got to know quite a few atrocity cases, many of which were recorded in diary letters he wrote to his wife and in letters to friends. McCallum remained in the hospital position throughout the massacre period. Meanwhile, he also served as a member of the International Relief Committee from June 1938 to July 1939, doing other relief work to protect and help Chinese refugees, when he was finally able to go back to the U.S."
—Suping Lu, They Were at Nanjing:
The Nanjing Massacre Witnessed by American and British Nationals (2004)