The demons do not pass him by. He has nightmares of his own in which he wallows in a bed of blood, or, panting, shouting soundlessly, runs from the man with the face like a hawk, like a Benin mask, like Thoth. One night, half sleepwalking, half demented, he strips his own bed, even turns the mattress over, looking for stains. (14.55)
The word "demons" in this passage is especially interesting; it implies that David is tormented by an inhuman and otherworldly outside force. His nightmares, which seem particularly gruesome and disturbing, follow suit.