Because he cannot concentrate it on Gettysburg.
It comes back jocosely
And he says, “A bear bit it off.”
And the boy wonders, while the old soldier
Dumbly, feebly lives over
The flashes of guns, the thunder of cannon,
The shrieks of the slain,
And himself lying on the ground,
And the hospital surgeons, the knives,
And the long days in bed.