This stereocard by Gettysburg photographer L. Mumper shows a Union surgeon performing an amputation. More than half of the legs hit by musket balls in the Civil War were treated by amputation. The only painkiller used was alcohol. Many amputees died of gangrene. During the Civil War, the U.S. military barred women surgeons from working in field hospitals at the front. It was while Walker (dressed in civilian clothing) was performing an amputation alongside a Confederate surgeon that the Confederates captured her.