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 whether mesmerism could induce a "suspension of consciousness" and indefinitely extend a person's life until a cure could be found. The experiment went horribly wrong, as Valdemar died while in a mesmeric trance and his body immediately began to decompose.