Read it through once

You fancy me mad. Madmen know nothing. But you should have seen me. You should have seen how wisely I proceeded — with what caution — with what foresight — with what dissimulation I went to work! I was never kinder to the old man than during the whole week before I killed him. And every night, about midnight, I turned the latch of his door and opened it — oh so gently! And then, when I had made an opening sufficient for my head, I put in a dark lantern, all closed, closed so that no light shone out, and then I thrust in my head. Oh, you would have laughed to see how cunningly I thrust it in! I moved it slowly — very, very slowly, so that I might not disturb the old man's sleep. 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.