From sideshows to scientific studies, hypnosis still intrigues.
On stage and screen, hypnotists make their subjects cluck like chickens, fall in love, rob banks and commit murder - activities the subjects supposedly can't recall once the trance is broken. But stage acts and creative license aside, hypnosis is simply a state of heightened attention in which suggestions appear to powerfully affect a person's subsequent behavior. Since the early 1800s, practitioners of hypnosis have attempted to harness that power in efforts to help patients manage pain, overcome phobias and change unwanted behavior, such as smoking and overeating.
In 1841, a respected Scottish-born surgeon living in Manchester, England, watched a public demonstration by traveling Swiss "magnetizer" Charles Lafontaine.
Like other magnetizers of the time, Lafontaine posited that an abundance of magnetic fluid in his body enabled him to put subjects into a trance by merely passing his hands before their faces and over their bodies. Once subjects were so entranced, magnetizers demonstrated apparent control of their behavior.
Though a panel of scientific experts (including Benjamin Franklin) had debunked the notion of a bodily magnetic fluid decades earlier, magnetizers (also known as "mesmerists" after the German doctor, Franz Mesmer, who put forth the practice) continued to con observers - including the surgeon James Braid.
"One fact, the inability of a patient to open his eyelids, arrested my attention," Braid later wrote of Lafontaine's demonstration. "I considered that to be a real phenomenon, and was anxious to discover the physiologic cause of it."
Braid rejected the idea of a magnetic fluid in the body, but he immediately attempted to demystify the phenomenon, testing it out on his wife and friends. He found that having his subjects stare at and concentrate on a bright object held before their eyes forced the eyes to close and brought on a state resembling sleep.
The staring paralyzed the eye muscles, he (erroneously) concluded, and the fixed attention weakened the mind, resulting in an unusual state of the nervous system, halfway between sleep and wakefulness - a state Braid dubbed "hypnosis." (His inspiration was the Greek hypnos, meaning "to sleep.")
Braid proposed that hypnosis would have a number of clinical uses. By slowing circulation, he suggested, it would be useful in surgery. By relaxing the muscles, he proposed, it could be used to straighten a curved spine. And with the patient's attention fixed, he wrote, the hypnotist could "fix certain ideas ... on the mind of the patient, which thereby act as stimulants, or sedatives."
In the decades that followed Braid's experiments, hypnotism popped up in sideshows, short stories and surgical theaters. Traveling hypnotists stunned audiences in Europe and the U.S. by plunging needles into the flesh of the entranced. A British surgeon working in India claimed to have performed hundreds of painless operations relying on hypnosis alone.
Braid's procedure was also picked up on by renowned French neurologist Jean-Martin Charcot, who began using hypnotism at Paris' Salpêtrière Hospital - and who eventually concluded that the technique only worked on hysterical women.
Hippolyte Bernheim, a professor at a university a few hours east of Paris, remained convinced that anyone could be hypnotized, not just the hysterical; he put forth the view that some people merely went into a state of hypnosis more easily than others.
For much of the rest of the 19th century, in fact, physicians and psychologists struggled to prove whether hypnotism worked - and if so, how it worked. Competing theories were put forth, debated and neither uniformly embraced nor rejected - until finally hypnotism seemed to fall out of favor for good.
But hypnotism was revived during World War I and again in World War II, both times in endeavors to treat the psychological traumas brought on by battle. And in the years since the second World War, the technique has steadily gained prominence in mainstream medicine.
By now, hypnotism has been endorsed by medical associations and is covered by many insurers. It's also under increasing scientific scrutiny by researchers at top universities. They're trying to determine whether the technique can help manage pain, reduce hot flashes in women, treat irritable bowel syndrome and help patients cope with the stress of surgery.
Ultimately, researchers hope studies will unveil hypnotism's lasting mystery - precisely how forced concentration combined with the power of suggestion can sometimes appear to work nearly as well as a drug.