The Killer Angels by Michael Shaara

The hospital was an open field just back of the line.

There were small white tents all over the field and bigger tents where the surgeons did the cutting. Hood was there, in a big tent, on a litter. Longstreet came in out of the dark, bowing under a canopy, saw the face like cold marble in yellow candlelight, eyes black and soft like old polished stones. Cullen and Maury were working together on the arm. Longstreet saw; not much left of the hand. Exposed bone. He thought of Jackson hit in the arm at Chancellorsville: died a slow death. Let us cross over the river.