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.

Hospital ships and Smallpox barges.

A United States general hospital was constructed at Mound City, on the Ohio, a few miles above its junction with the Mississippi, early in the war. On September 29, 1862, Secretary Welles authorized the construction of a marine hospital also. The place was so named because of the existence of a slightly elevated bit of ground covered with trees, though at the beginning of the war only a few houses made up the ‘city.’ Smallpox epidemics caused 12,236 admissions to the Union hospitals, with 4,717 deaths. The patients were quarantined in separate hospitals or on boats and barges along the rivers, and the utmost care was taken to prevent the spread of the disease which was the cause of such a frightful mortality. The courage and devotion of the medical men and hospital orderlies who risked their lives to combat it cannot be praised too highly.

Tin clad 59, and tug opposite the mound city hospital

A full length hospital ship red rover

A smallpox barge on the Mississippi