Distillations magazine

Unexpected Stories from Science’s Past
December 6, 2011 Health & Medicine


The controversy around animal magnetism.

Detail of Franz Anton Mesmer portrait

In the late 1770s, in the midst of the French Enlightenment, Franz Anton Mesmer was at the height of his medical career. Hundreds of people flocked to be cured by the man in the lilac taffeta robe who waved his hands and an iron rod over his patients’ bodies, sending them into fits as they fell to the ground. Mesmer believed he had discovered a fluid, something akin to electricity, which he called animal magnetism. He also believed he could control the flow of this fluid, which he claimed governed, penetrated, and surrounded all bodies, and use it to heal patients.

Born in 1734 into a somewhat large and poor family in Swabia (southern Germany), Mesmer went on to study theology before switching to medicine in 1759. For his dissertation Mesmer wrote about the planets’ invisible influence on the human body, an approach that fitted with the newly mainstream concept of Newtonian gravity. Mesmer termed the force animal gravity, later to become animal magnetism.

In 1774 Mesmer began treating a young woman who had a long list of symptoms—fevers, vomiting, unbearable toothaches and earaches, delirium, and even occasional paralysis. Her illnesses had a cyclical nature, which led Mesmer to try out his animal magnetism as a curative. Mesmer used magnets to control the misbehaving fluid, and his patient became the first person to be mesmerized and cured of her medical troubles.

Mesmer’s medical successes were soon tarnished by controversy about both his treatments and his inappropriate relationships with female patients. He moved his medical practice from Vienna to Paris, the continent’s scientific capital. By 1778 Newton’s physics ruled, and many saw no essential difference between Mesmer’s animal magnetism and the invisible force that Newton argued moved the planets around the Sun.

Mesmer, who truly believed in his ability to control his invisible fluid, quickly gained fame, fortune, and many patients. He created the baquet, a shallow wooden tub filled with magnetized water and iron bars that was large enough to treat thirty patients at a time. Patients would link hands while sitting in the baquet to allow the magnetic fluid to circulate. Many of Mesmer’s patients responded to these therapies and claimed themselves cured, but he also faced skeptics, including Jean Baptiste LeRoy, head of the French Royal Academy of Sciences. Yet patients both rich and poor flocked to these treatments.

Academic suspicion peaked in 1784 when King Louis XVI appointed a royal commission to investigate. The commission included such scientific heavyweights as Benjamin Franklin and Antoine Lavoisier. After investigating mesmeric treatments, which included what is probably the first blind trial, the commission published a report the same year dismissing mesmerism’s effects as illusions caused by patients’ imaginations. The report to the Academy was read aloud by Jean-Sylvain Bailly, the Academy astronomer (CHF’s Othmer Library has a copy of this report, Rapport des commissaires chargés par le roi de l’examen du magnétisme animal). Bailly also summarized the results, highlighting the importance played by imagination and imitation, two of humanity’s “most astonishing faculties,” and asked for further studies on their influence over the body.

The commission published over 20,000 copies of the report. Mesmer was outraged and offered to mesmerize a horse as irrefutable proof of his technique’s effectiveness. But the mesmeric tide was ebbing, leaving Mesmer stranded. He left Paris, though some of his followers continued his practices. In 19th-century Britain mesmerism enjoyed a short-lived vogue. Today, Mesmer’s work lives on in two unexpected ways: in the word mesmerize and through the recognition that the mind’s response to a medicine has physical effects on the body.

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