The document discusses the case of M. Valdemar, a man who was mesmerized by Edgar Allan Poe while on his deathbed from terminal illness. Poe was interested in exploring whether mesmerism could induce a "suspension of consciousness" and indefinitely extend a person's life until a cure could be found. The experiment with M. Valdemar appeared to place him in a trance state just before his death, leaving his physical form in a semi-living state for several weeks.