Brainstuff is not lean stuff;—the brainstuff of fiction is internal history, and to suppose it dull is the profoundest of errors; how deep, you will understand when I tell you that it is the very football of the holiday-afternoon imps below. They kick it for pastime; they are intelligences perverted. The comic of it, the adventurous, the tragic, they make devilish, to kindle their Ogygian hilarity.
Source: wiktionary