During the war the Confederates captured about 211,000 Federal soldiers. Of this number, 16,000 agreed to battlefield paroles—signed promises that they would not bear arms again. Conversely, Federal forces took some 215,000 Confederates as prisoners. At various times throughout the war, both sides made efforts to establish a workable program of prisoner exchange. (A ratio of exchange once existed whereby forty privates equalled one major-general.) However, owing to misunderstandings, violations of terms, and Grant’s determination late in the war to bring the South to its knees at all costs, prisoner exchange was slight and sporadic. The most notorious Southern prisons were: Libby and Castle Thunder, which were converted warehouses in Richmond; Belle Isle in the James River; “Camp Sorghum” at Columbia, S. C.; and Camp Sumter at Andersonville, Ga. Among the worst of the Northern compounds were: Elmira Prison Camp in southwestern New York State; Point Lookout, on the Chesapeake Bay; Johnson’s Island, in Lake Erie a few miles offshore from Ohio; Camp Douglas, near Chicago; and Rock Island Prison Camp, Illinois. Writing of these compounds in general, one historian has observed: “The prisons of the Civil War were of a considerable variety in structure and general make-up and for the most part consisted of temporary structures or old unused buildings not originally intended to confine prisoners. Most of them, judged by present-day standards of sanitation and safety, would have been condemned as uninhabitable.” [Illustration: This is an artist’s conception of the horrors of life in Andersonville. The hastily built camp spread over 26 acres.] [Illustration: A _Harper’s Weekly_ artist sketched an orderly and clean Elmira Prison that was a far cry from actual conditions. For a modest sum, curious townspeople were permitted to mount observation towers and view the prisoners.] Small wonder that great suffering existed in most prison camps, both North and South. In the nine-month history of the huge prison at Andersonville, Ga., a total of 45,613 Federals were jammed into a Stockade containing one polluted stream of water, few shelters, less food, and no sanitation. Over 12,900 prisoners died of disease, exposure, and starvation at Andersonville. Confederate authorities maintained that Federal prisoners in Andersonville received the same slim food ration as did their guards, and that the whole South suffered badly for want of medicines. [Illustration: Only captured Federal officers were confined in Libby Prison. Several escapes, and innumerable charges of inhuman treatment, marked this compound’s four-year history.]