HD Article

Dr Franz Anton Mesmer and the Placebo Effect

To "mesmerize" is to enthrall. And that is exactly what Viennese physician Franz Anton Mesmer did to the patients who flocked to his healing salon in the middle of the 18th century. Mesmer's "healing" was based on his belief that the universe was permeated with an invisible fluid that connected people to the planets and to each other. The motion of the planets, he suggested, influenced the fluid, which in turn influenced people's health. Accordingly, "influenza" was a disease attributed to the shifting of heavenly bodies.

Long before Mesmer, Paracelsus, the famed 16th-century physician and alchemist, had philosophized about a universal fluid to explain what he believed were changes in the body that reflected changes in the solar system. Essentially this was an attempt to rationalize a belief in astrology. Paracelsus claimed that the universal fluid had magnetic properties and could be guided into afflicted parts of the body by magnets. He based this view on his personal observation of "healing" patients by passing a lodestone, which is a naturally occurring magnet, over their bodies. Unbeknownst to him, Paracelsus was witnessing the powerful mind-body connection that eventually came to be called the placebo effect.


mind over medicine


Paracelsus' ideas carried significant weight. Even Isaac Newton contemplated the idea that the universe was permeated with an "aether" that allowed for the transmission of light, gravity and magnetism. So by the time Mesmer appeared on the scene, the idea of some sort of cosmic magnetism was quite firmly entrenched. And when Mesmer witnessed one of his mentors, Viennese Jesuit Maximilian Hell, carry out apparent healings by applying steel plates to the bodies of the ill, he concluded that magnetic healing was the wave of the future for medicine. This was an attractive idea for patients because sitting around and gripping magnetized metal rods connected to a tub filled with iron filings was preferable to purging and bleeding, the common conventional medical treatments of the time.

Mesmer went on to explore other means of restoring the body's magnetic fluid, and found that having patients sit with their feet in magnetized water while holding cables attached to magnetized trees worked well. It was a classic case of coming to the wrong conclusion based on a correct observation. Patients really did report feeling better, which of course is not the same as being better. But the effect didn't have anything to do with magnetized water or trees, neither of which can be magnetized.

Based on the positive reports from his patients, Mesmer became convinced that illness was indeed caused by some sort of depletion in an invisible magnetic fluid, and that restoration of the fluid was curative. He assumed that healthy people were permeated with the fluid and began to wonder whether they could transmit some of their excess to the afflicted the same way that it was transmitted from magnets, which he assumed were loaded with it. Before long, he discovered that indeed the healing fluid could be passed from the healthy to the ill, prompting him to hatch the theory of "animal magnetism." He chose the term "animal" from its Latin root "animus," meaning "breath," to imply that this was some sort of life force that was possessed by all creatures with breath, namely humans and animals. This force could be passed from the healthy to the ill either by direct contact or even by just being in proximity.

But even this idea was not novel. Long before, the ancient Chinese had spoken of some sort of life force called "chi" that travelled through the body's energy channels, and Hindu culture featured "chakras" that were believed to be some sort of intangible energy centres in the body. Today, practitioners of "reiki" and "therapeutic touch" rationalize their efforts by claiming an ability to manipulate the body's energy field, sometimes described as an aura. This sounds very much like Mesmer's transference of animal magnetism. Modern science has found no evidence for any sort of energy centres or channels or invisible fluids, but there is no question that many patients claim to have experienced positive effects after having such seemingly nonexistent entities manipulated. It is likely that the thread that ties all these healing modalities together is the power of belief.

Mesmer himself was forced out of Vienna by a jealous medical establishment that was losing patients to the newcomer. He then set up shop in Paris, catering mostly to wealthy hypochondriacs. Dressed in a long robe embroidered with astrological symbols, he made for an imposing sight as he stared into the eyes of patients and triggered reactions ranging from sleeping to dancing and even convulsions. All these are familiar to scientists who study hypnosis, which is essentially what Mesmer was practising. Good-looking young men were hired as assistants to sit knee to knee with ladies to massage whatever ailment they had out of their bodies. Sometimes the curative work was continued in private rooms where the subjects could experience personal satisfaction without guilt.

As had happened in Vienna, French physicians felt threatened by Mesmer's antics. They persuaded King Louis XVI to set up a royal commission to investigate Mesmer and his cosmic fluid. The king was keen because he was not pleased that the queen, Marie Antoinette, had fallen under Mesmer's spell. Mesmer refused to co-operate with the commission, but at the behest of a visiting-from-America Benjamin Franklin -- who, along with chemist Antoine Lavoisier and physician Joseph Guillotin, was a member of the commission -- an experiment was designed that may well have been the first controlled trial using a placebo ever conducted. Blindfolded patients were shown to respond to a non-magnetized tree as well as to one that was magnetized by Mesmer's methods. The committee's conclusion was that "the imagination without the magnetism produces convulsions, and the magnetism without the imagination produces nothing."

Mesmer left Paris and died in obscurity in Switzerland in 1815, but maintains a prominent place in medical history for having stumbled upon and popularized the power of imagination in influencing health. Interestingly, around the same time, Samuel Hahnemann came up with the theory of homoeopathy, another practice that has no physiological basis. The effect on patients was the same as mesmerism, although the explanation of the effects was totally different. Both Mesmer and Hahnemann were unknowing pioneers of the power of the placebo.

Joe Schwarcz is director of McGill University's Office for Science & Society (

Copyright (c) The Montreal Gazette

Republished with the permission of the author.


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