A sprawling institution on the outskirts of the city, Chimborazo was reportedly the largest military hospital in the world in the 1860s. By the end of the Civil War, the hospital had cared for some 76,000 patients. Pember served as Chief Matron of one the facility's five divisions. It was an unusual job for a woman, at a time when virtually all nursing was done by men. Pember's varied duties surely required what one of her contemporaries described as her "will of steel under a suave refinement." Although Pember had to thwart efforts by her staff to pilfer supplies, once reportedly threatening a would-be thief with a gun, she also seems to have been accepted and valued by patients. Lacking adequate food, medicine, and other supplies, often that warm presence was the best that Pember and her staff could offer. Although she dedicated herself to relieving the suffering of soldiers, she was often simply a final companion for the dying.