Read it through once

At length the officers were satisfied. They rose to depart; and I felt that my victory was complete. They were walking about. I invited them to sit, and they sat. They conversed pleasantly about trivial matters. And all the while, I could hear a low, dull, quick sound, such a sound as a watch makes when enveloped in cotton. I knew that sound well. Every fiber of my body now began to itch. It increased my agitation. The sound grew louder. It was the beating of the old man's hideous heart.