For nearly as long as the human race has existed, people have been obsessed with the notion of prolonging life.  The first ever written story, The Epic of Gilgamesh, is about a king who goes in search of a plant that will help him to gain eternal life.  Emperor Qin Shi Huangdi of the Qin dynasty of China desperately sought the Elixir of Life, potion which would grant him immortality.  While he himself might not live forever, Hitler's "thousand year Reich" would sure live on, extending his life by extending his legacy.  The idea of delaying death has, and will always, fascinate people.  However, this is easier said than done.  

Edgar Allan Poe was one of the most popular Victorian horror writers.  One of his stories, The Facts in the Case of M. Valdemar, is the frightening tale of a doctor who manages to arrest the process of normal death by means of mesmerizing (hypnotizing) a man named M. Valdemar at exactly the point of his death.  Written like something out of a medical journal, The Facts in the Case of M. Valdemar had many people convinced that the experiment had actually been performed by Poe or someone he knew.  This, however, was probably exactly the effect Poe had hoped for.  Poe uses the fact that people would probably believe him, the gristly nature of the story, and the apparent failure of the experiment to critique the process of mesmerism.  

As you are reading this story, you can't help but think about how realistic Poe makes the whole thing sound.  Clearly it is a highly unrealistic story, but it is presented in such a way that makes one think that such a thing couldn't be entirely impossible.  Take for instance the way he begins his story.  By saying "I shall not pretend to consider it any matter for wonder, that the extraordinary case of M. Valdemar has excited discussion.  It would have been a miracle had it not   especially under the circumstances", he makes you think that this is practically common knowledge and that you should know about this already.  He also formats it almost clinically, leaving out the names of all parties except the (deceased) subject to protect the identities of those involved, paying close attention to minute details, and telling us that "Mr. L l was so kind as to accede to my desire that he would take notes of all that occurred; and it is from his memoranda that what I now have to relate is, for the most part, either condensed or copied verbatim" about half way through the story.  In addition to that, he even admits himself that "I now feel that I have reached a point of this narrative at which every reader will be startled into positive disbelief.  It is my business, however, simply to proceed."  He obviously knew that people would be skeptical.  However, by admitting this fact, he sows a grain of doubt into the skepticism.  Through legitimizing himself, he shows himself to be a credible source as he questions the process of mesmerism.

Calculated in such a way as to leave the reader with a slight feeling of revulsion, the tone of this story is used to further discredit the theory of mesmerism.  Poe was not one of the most popular horror writers of the Victorian Era for nothing.  Throughout this story, ghastly descriptions abound.  Even before his death, M. Valdemar is described as "[having] a leaden hue; the eyes were utterly lusterless; and the emaciation was so extreme, that the skin had been broken through by the cheek-bones."  After he dies, it gets worse; the skin "assumed a cadaverous hue" and the tongue of his gaping mouth was "swollen and blackened," a sight so disgusting that everyone present "shrunk back from the region of the bed".  As the narrator attempts to talk to the mesmerized (and dead) Valdemar, the voice that issues from his mouth is said to be "harsh, and broken and hollow; but the hideous whole is indescribable, for the simple reason that no similar sounds have ever jarred upon the ear of humanity".  There are many more of the like, arguably the most gory and gristly of them all is the final one in which, after P-- attempts to wake Valdemar, Valdemar "absolutely rotted away beneath my [P 's] hands.  Upon the bed, before that whole company, there lay a nearly liquid mass of loathsome of detestable putrescence."  Certainly not at a loss for creepy and disgusting imagery, Poe uses this to leave people with a negative impression of mesmerism.  

The final nail that Poe drives into the proverbial coffin of hypnotically extending life is the fact that the whole process didn't even really work.  Certainly, P  succeeds in mesmerizing Valdemar, but what did that accomplish apart from keeping him on this earth for 7 months longer than need be?  Not only that, but the narrator also describes how "any attempt to draw blood failed", that the arms were "no longer subject to my [P 's] will", and that "the only real indication of the mesmeric influence, was now found in the vibratory movement of the tongue."  Valdemar is unable to do basically anything except for repeat over and over again that he is dead.  If the point of the whole experiment was to see whether or not life could be prolonged via mesmerizing the dying, can you even call Valdemar's torturous existence life?  Certainly, even if you can, it is not a life worth living.  On all accounts, the experiment failed at achieving anything aside from 7 months more torment for Valdemar. 

No matter which way you slice it, Valdemar eventually died.  The experiment, real or not, failed in the most horrifying manner imaginable.  Poe had done his job.  He had debunked one of the more popular theories in the search for immortality, the theory that you could hypothetically continue life past death through mesmerism.  In the present day and age, it is an established fact that it is impossible to live forever.  Any person off the street can tell you that.  However, it was also impossible 100 years ago to fly, and now we are on our way to Pluto.  Who's to say immortality is impossible?  Who's to say we won't eventually conquer the Grim Reaper himself?

