The Photographic History of The Civil War: in ten volumes, Thousands of Scenes Photographed 1861-65, with Text by many Special Authorities, Volume 7: Prisons and Hospitals.
Francis Trevelyan Miller, Ed.

[346] during the continuance of the war, it matters not which party may have the surplus of prisoners, the great principles involved being, first, an equitable exchange of prisoners, man for man, officer for officer, or officers of higher grade exchanged for officers of lower grade or for privates, according to the scale of equivalents; second, that privateers and officers and men of different services may be exchanged according to the same scale of equivalents; third, that all prisoners, of whatever arm of service, are to be exchanged or paroled in ten days from the time of their capture, if it be practicable to transfer them to their own lines in that time; if not, as soon thereafter as practicable; fourth, that no officer, soldier, or employee, in the service of either party, is to be considered as exchanged and absolved from his parole until his equivalent has actually reached the lines of his friends; fifth, that the parole forbids the performance of field, garrison, police, or guard, or constabulary duty.