Circa1865

In April 1864 Gen. Grant, apparently with the approval of Lincoln, forbade Gen. Benjamin Butler “to deliver to the Rebels a single able-bodied man.”  Butler then wrote that “[the] facts abundantly show that the responsibility of refusing to exchange prisoners of war rests with the Government of the United States, and the people who have sustained that government; and every sigh of captivity, every groan of suffering, every heart broken by hope deferred among [the North’s] eighty thousand prisoners [in Southern prisons], will accuse them in the judgment of the just.”  Lincoln kept his own men starving in Southern prisons in order to deny the South any returned soldiers.
Bernhard Thuersam, www.circa1865.org

Prisons Holding Independence-Minded Americans

“For the common soldier in prison, survival was a daily struggle. James Huffman of the Tenth Virginia Infantry was one who lived to write his reminiscences of prison life:

“Elmira Camp was a very sickly place. The death rate was much higher than in the army during active hostilities. About half of us Virginians — and I think three-quarters of all the Southerners — died here in eight to ten months. A large number of North and South Carolinians had been captured at a Fort on the North Carolina coast — hale, hearty looking fellows except that they were yellow from lying in the trenches.

These men crowded us very much at first, but in two or three weeks they were nearly all gone to the hospitals, and most of them died. The well water looked pure and good but was deadly poison to our men, thousands taking chronic diarrhea from which they died. We had smallpox almost all the time. One doctor there said he killed more Rebs than any soldier at the front.”

(True Tales of the South at War, Clarence Poe, editor, UNC Press, 1961, pg. 147)