That thousand yard stare is an anachronism I borrowed from WWII marines accounts of when a man had had too much and was about to lose it. In this photo of Ed Buford, Sr., of Clack's/Brown's 3rd Tenn Inf, you can see it in his eyes. The photo was taken in Nashville sometime between Ed's return home in June 1865 and August 1866 (it has a revenue stamp on the back). Ed did two stints as a POW, once from Fort Donelson, and one from May 1864 to March 1865. After his second exchange, he fell off a moving train in North Carolina, delaying his return home. His obit says he was the only man in his unit not to fall out on the march from Mississippi to Bragg in Tennessee just before Chickamauga. This is the only Civil War photo I've seen that has that stare.