"An Incident" is part of a larger entry in
Specimen Days titled "Hospital Scenes.--Incidents." This larger entry contains two accounts or observations from the hospital (Carver hospital) and two tellings of happenings on the battlefield after the fighting that day had finished. The writing in all of these accounts is very straightforward and blunt, as we will find in a moment. These other smaller entries don't have any bearing on the text Rorem chose to set, so I will simply point you to
where you can read them, if you are interested.
An Incident
In one of the fights before Atlanta, a rebel soldier, of large size, evidently a young man, was mortally wounded top of the head, so that the brains partially exuded. He lived three days, lying on his back on the spot where he first dropt. He dug with his heel in the ground during that time a hole big enough to put in a couple of ordinary knapsacks. He just lay there in the open air, and with little intermission kept his heel going night and day. Some of our soldiers then moved him to a house, but he died in a few minutes.