Rena's Experiment by Mary Jane Holmes

Rex seemed worse, perhaps, than he really was, because of the delirium which increased rapidly after his interview with Rena. The sweat which stood in so big drops upon his face and hands was gone, leaving his skin parched and dry. His head was very hot and rolled from side to side, following the eye, which he said was watching him and moving from point to point. Sometimes it dropped upon the pillow over his shoulder and sometimes on the bed close to him, when he would try to brush it off. How the idea of the eye originated I could not guess, but Colin knew, and after listening awhile to Rex's ravings he left the room muttering something about stopping the infernal nonsense. Calling Nixon he bade him take some heavy planks and cover up the well, putting a big stone on the centre plank, so it could not be removed easily. Then he came back, and sitting down by Rex tried to quiet him, telling him the eye was in the well with the mirror, and he had covered it up.

"You needn't tell me that," Rex said. "It's on your coat-sleeve, this minute, winking up at you. Don't you see it."