Quotes from book
The Tell-Tale Heart
"The Tell-Tale Heart" is a short story by American writer Edgar Allan Poe, first published in 1843. It is related by an unnamed narrator who endeavors to convince the reader of the narrator’s sanity while simultaneously describing a murder the narrator committed. The victim was an old man with a filmy "vulture-eye", as the narrator calls it. The narrator emphasizes the careful calculation of the murder, attempting the perfect crime, complete with dismembering and hiding the body under the floorboards. Ultimately, the narrator's feelings of guilt, or a mental disturbance, result in hearing a thumping sound, which the narrator interprets as the dead man's beating heart.

“And now have I not told you that what you mistake for madness is but over-acuteness of the senses?”
The Tell-Tale Heart (1843)
Context: And now have I not told you that what you mistake for madness is but over-acuteness of the senses? -- now, I say, there came to my ears a low, dull, quick sound, such as a watch makes when enveloped in cotton. I knew that sound too. It was the beating of the old man's heart. It increased my fury, as the beating of a drum stimulates the soldier into courage.