A true Janian reply! Good angels be my guard! She comes from the other world—from the abode of people who are dead; and tells me so when she meets me alone here in the gloaming! If I dared, I'd touch you, to see if you are substance or shadow, you elf!—but I'd as soon offer to take hold of a blue _ignis fatuus_ light in a marsh.
Chapter 22 · Edward Rochester
Context
When Jane tells Rochester she has been with her recently deceased aunt, he responds with exaggerated alarm, calling her reply characteristically blunt ('Janian') and playfully suggesting she seems ghostly or supernatural.
Analysis
Rochester piles up metaphors—'substance or shadow,' 'elf,' 'ignis fatuus'—that all cast Jane as something spectral and elusive, never quite human or fully graspable. The Latin phrase 'ignis fatuus' (will-o'-the-wisp) is particularly telling: it's a light that leads travelers astray in marshes, which frames Jane as both alluring and dangerous to follow. His humor masks a real unease: he can't categorize her, and that slipperiness unsettles the control he's used to having.
Essay Tip
Support a thesis that Rochester's habit of calling Jane supernatural ('elf,' 'fairy,' 'sprite') isn't just affectionate teasing—it's a way of avoiding acknowledging her as a full human equal, which would force him to confront the social impossibility (and moral necessity) of loving her instead of Miss Ingram.