Animal magnetism, also called mesmerism, was the theory developed by the German physician Franz Anton Mesmer (1734-1815) that an invisible natural fluid flows through all living beings and that illness results from its obstruction. Mesmer's dramatic treatments made him famous in Paris, but a royal inquiry in 1784 rejected the fluid. His methods nevertheless led to hypnosis.
Animal Magnetism at a glance
| Also known as | Mesmerism |
|---|---|
| Founder | Franz Anton Mesmer (1734-1815) |
| Main period | Late 18th to mid-19th century |
| Key places | Vienna, then Paris from 1778 |
| Official inquiry | French royal commissions, 1784 |
| Later development | Hypnotism, named by James Braid in the 1840s |
Origins
Franz Anton Mesmer was born in 1734 near Lake Constance in Swabia and studied medicine in Vienna. His doctoral dissertation (1766) discussed the influence of the planets on the human body, an idea with roots in older astrology and in the medical speculation of writers such as Paracelsus. In the 1770s he experimented with magnets to treat patients, then concluded that the healing agent was not the metal but a force within living bodies, which he called animal magnetism.
According to Mesmer, a subtle universal fluid fills the cosmos and passes through the nerves. Disease arose when its flow was blocked, and health returned when the physician, acting as a conductor, restored harmony. After a controversy over the treatment of a blind pianist in Vienna, he moved to Paris in 1778.
In 1768 Mesmer married a wealthy widow, Maria Anna von Posch, and moved in Vienna's cultivated society; the young Mozart's early opera Bastien und Bastienne is traditionally said to have been performed at his home.
Practice in Paris
In Paris Mesmer attracted aristocratic and middle-class patients. Because demand was high, he treated groups around the baquet, a wooden tub filled with water, iron filings and bottles, from which iron rods reached the patients. Participants held hands or were joined by cords while Mesmer or his assistants made passes with their hands, sometimes to music.
Many patients experienced a "crisis": trembling, crying, laughing or convulsions, followed by a feeling of relief. Mesmer interpreted these reactions as signs that the fluid was flowing again. His followers formed the Society of Harmony, which taught the method for a fee. Critics saw the sessions as theatrical, and the medical faculty of Paris remained hostile.
The 1784 royal commissions
In 1784 King Louis XVI appointed commissions to examine animal magnetism. One included members of the Academy of Sciences and the Faculty of Medicine, among them Benjamin Franklin, the chemist Antoine Lavoisier, the astronomer Jean-Sylvain Bailly and the physician Joseph-Ignace Guillotin. The commissioners studied the practice of Mesmer's former pupil Charles d'Eslon and carried out tests.
In some trials, subjects who believed they were being magnetized reacted strongly even when nothing was done, while subjects who did not know they were being treated showed no response. The commission concluded that there was no evidence of a magnetic fluid and that the effects came from imagination, imitation and touch. Historians often cite these tests as an early use of blind procedures and a landmark in the study of what is now called the placebo effect.
From mesmerism to hypnosis
The same year, the Marquis de Puysegur described a calm "magnetic sleep" in which patients seemed to talk and obey suggestions while in a trance-like state. This "artificial somnambulism" shifted attention from convulsive crises to altered states of mind. During the nineteenth century mesmerism spread across Europe and America, both as popular stage entertainment and as a form of therapy.
In the early 1840s the Scottish surgeon James Braid argued that such trances depended on the subject's focused attention and suggestion rather than on any fluid, and he introduced the term "hypnotism." Later physicians such as Jean-Martin Charcot and Hippolyte Bernheim studied hypnosis, and it influenced early psychotherapy, including the young Sigmund Freud.
In Britain, the physician John Elliotson promoted mesmerism at University College London and resigned in 1838 after controversy. In India in the 1840s, the Scottish surgeon James Esdaile reported performing many operations on patients in a mesmeric trance, shortly before ether and chloroform came into use. Whatever the theory, practitioners were exploring real methods of reducing pain through focused attention and suggestion.
Legacy in spiritualism and esoteric thought
Animal magnetism fed several later movements. Magnetizers reported subjects who seemed to see distant places or diagnose illness, claims that anticipated later ideas about clairvoyance and psychometry. American mesmerists such as Phineas Parkhurst Quimby moved toward mental healing, a line that led to the New Thought movement. Spiritualists and occultists, including Helena Blavatsky, discussed magnetism as evidence of hidden forces in nature.
Today animal magnetism is regarded by science as a disproven theory: no magnetic fluid has ever been detected. Its history remains important, however, because it shows how genuine psychological effects, such as suggestion and expectation, can be explained by mistaken physical theories.
Related entries
Frequently asked questions
What is the difference between animal magnetism and hypnosis?
Animal magnetism claimed that healing came from an invisible physical fluid transmitted by the practitioner. Hypnosis, as described by James Braid and later researchers, explains trance and suggestibility through attention, expectation and suggestion. Hypnosis grew out of mesmerism but abandoned the idea of a magnetic fluid.
Did Benjamin Franklin investigate Mesmer?
Yes. In 1784 Franklin, then the American envoy in France, served on a royal commission with Lavoisier, Bailly and Guillotin. The commission tested magnetic treatments and concluded that the effects were due to imagination rather than any fluid. Its report became a classic early example of controlled testing.
Is animal magnetism real?
The fluid Mesmer described has never been detected, and the 1784 commissions found no evidence for it. The reactions of patients were real, but researchers attribute them to suggestion, expectation and social influence. Modern science therefore treats animal magnetism as a historical theory rather than a physical force.
Sources and further reading
- Franz Anton Mesmer · Encyclopaedia Britannica
- Animal magnetism · Wikipedia
- Robert Darnton, Mesmerism and the End of the Enlightenment in France (1968) · Book
This entry replaces an article from the original Mystica encyclopedia (online since 2001). It was rewritten from the sources above by The Mystica Editorial Team under our editorial standards. Last reviewed: September 30, 2026.