Franz Anton Mesmer (1734-1815)

by Jessica Riskin
Associate professor of History
Stanford University

Franz Anton Mesmer, a doctor from the Swabian village of Iznang, was born on 23 May 1734, the third of nine children of a gamekeeper and forest warden to the Archbishop of Constance. Mesmer tried philosophy, theology and law before settling upon medicine, receiving his degree from the University of Vienna in 1766 for a dissertation on the influence of the planets upon the human body entitled Dissertatio physico-medica de planetarum influxu. Influenced by the views of the 16th century alchemist Paracelsus, the dissertation was also largely plagiarized from the English physician Richard Mead's De imperio solis ac lunae in corpora humana et morbis inde oriundis (1704). Mesmer joined the medical faculty at the University of Vienna in 1767 and, the following year, married a rich widow, Maria Anna von Posch. Her fortune supported her husband's burgeoning career, though her justifiably suspicious family placed increasing constraints on his access to it, while her luxurious estate in the Landstrasse offered a venue for the sumptuous musical soirées he liked to host. (Mesmer was a music enthusiast, an impresario of the glass harmonica, and a friend, frequent host and patron to the young Mozart.)

In his medical practice, Mesmer initially adopted a technique from the Jesuit astronomer Maximilian Hell, who moonlighted in medicine, applying magnets to his patients' ailing parts. Mesmer soon elaborated this practice, adding a theory from his doctoral thesis, which hypothesized a fluid from the stars that flowed into a northern pole in the human head and out of a southern one at the feet. He also added more magnets, to channel the ebb and flow of the astral current, before dispensing with magnets altogether, leaving the doctor's bare hands and magnetic personality as the principle therapeutic instruments. Illness, Mesmer taught, resulted from obstructions of the animal magnetic fluid, which he claimed to remedy by touching his patients' bodies at their poles. The cures, which involved violent "crises" with fits of writhing and fainting, reminded contemporaries of the recently invented electrical capacitor, the Leyden jar, which sent a fiery commotion through the bold (or careless) experimenter who discharged it by touching it. The crises, and Mesmer's flamboyant style in producing them, contributed to the notoriety of his methods.

He became an increasingly public and controversial figure, giving lectures and demonstrations throughout the Hapsburg empire. In 1777, he fatefully acquired a prominent patient, Maria Theresia von Paradis, blind daughter of a senior civil servant and goddaughter and namesake of the dowager empress Maria Theresa. Paradis was then eighteen, an accomplished pianist, harpsichordist and singer with a future career as a performer and composer. Mesmer's treatment of her churned the ongoing disputes surrounding his science - its authorship, its efficacy, its moral rectitude - into a violent storm. He fled, leaving his patients in the care of his beleaguered wife. Having exhausted her family's tolerance and Vienna's credulity, he went to Paris.

Arriving in February 1778, Mesmer established a clinic in the Place Vendôme that became an overnight success. Soon mesmeric salons had sprung up throughout the city. Inside, their atmosphere was murky and suggestive, with drawn curtains, thick carpets and astrological wall-decorations. Mesmer himself dressed impressively in a lilac taffeta gown. Patients gathered, joined by ropes, around baquets, tubs filled with miscellaneous bits of glass, metal, and water, from which flexible iron rods protruded. They pressed these rods to their left hypochondria (upper abdomens), and joined their thumbs to increase the communication of the magnetic fluid. Alternatively, they opposed their own magnetic poles to those of the magnetizer (Mesmer himself or one of the many followers he quickly attracted) by placing their knees between his. He then pressed and prodded their bodies with a mesmeric wand, or, more often, his fingers. By means of these titillating practices, he provoked the notorious mesmeric crises. For especially violent crises, mesmeric salons included separate rooms lined with mattresses. Unable to attend to all the ailing Parisians who arrived in droves on his doorstep, Mesmer was forced to designate a surrogate: he "magnetized" a tree near the porte Saint-Martin to accommodate the overflow.

His quest for official sponsorship met with more mixed results. Mesmer applied for endorsement to the Academy of Sciences, the Society of Medicine and the Faculty of Medicine. Like the ebb and flow of the astral tide, the philosophes were attracted and repelled by Mesmer's doctrine. Jean Baptiste Le Roy, director of the Academy of Sciences, invited Mesmer to present his theory at an Academy meeting and hosted a demonstration of it in his own laboratory. This first display of Mesmer's science in Paris was greeted with outright laughter. Afterwards, Le Roy would have nothing to do with Mesmer. Félix Vicq d'Azyr, perpetual secretary of the Society of Medicine, rapidly developed the same attitude, as did the delegation of twelve members of the Faculty of Medicine who agreed to witness a series of Mesmer's treatments. The chemist Claude-Louis Berthollet joined the mesmeric Société de l'harmonie universelle but stormed out in mid-session after a fortnight, proclaiming that he had been duped. However, a significant contingent at the Faculty of Medicine were converted to mesmerism, including Charles Deslon, physician to the Comte d'Artois; Mesmer also won the admiration and patronage of Marie Antoinette. "Never," the commissioners later appointed to investigate mesmerism would pronounce, "has a more extraordinary question divided the minds of an enlightened Nation."[1]

Though his manner was extravagant, Mesmer's views were not out of keeping with contemporary natural science. When he related health to the regulation of so-called "imponderable" (weightless) fluids in the body, he drew upon the developing physics of imponderables - light, heat, electricity, magnetism - and gave expression to a view that was widely held among doctors and physiologists. Moreover, throughout his writings on animal magnetism - Mémoire sur la découverte du magnétisme animal (1779), Précis historique des faits relatifs au magnétisme animal (1781), Aphorismes de M. Mesmer (1785), Mémoire de F.A. Mesmer...sur ses découvertes (1799) - Mesmer used a standard sensationist language. His followers did the same; they characterized their doctrine as rigorously empirical. To be sure, the regular five senses could not directly detect the animal magnetic fluid, but the same was true of other imponderable fluids too. One could see neither magnetism, nor the subtle cause of heat, nor the force of gravity. Like these other fluids, the animal magnetic aether made itself known through its effects.

Moreover, Mesmer claimed that animal magnetism provided a material foundation for sensation itself, a subtle fluid acting upon the nerves. This, too, was a direct extrapolation from contemporary sensory physiology, from the nervous aether common to post-Newtonian theories of sensation. Mesmer also, at times, called the animal-magnetic basis of sensation a "sixth sense" and invoked its sensory nature to explain why he could neither describe nor define it. Senses were prior to ideas and could only be "experienced."[2] Mesmer's sixth sense, the basis of all sensation, connected the individual to the whole universe and to the past and future, bringing people into "rapport" with all of history and with the minds of others.[3]

Here, again, Mesmer drew on physiologists' accounts of sensation as the interface between aetherial fluids inside and outside the brain. The subtle fluid of light, for example, according to the prevailing view, impressed itself upon the eye, setting the eye's nervous fluid in motion toward the brain. In the same way, Mesmer's sixth sense registered the movements of the universal fluid through which all events reverberated. These reverberations could reflect the past, foretell the future, and receive the imprint of human thoughts. For the internal sense to function at its peak, the other senses must be silent, as was the case during sleep or hypnosis, a technique developed by one of Mesmer's disciples, the marquis de Puységur. He claimed his hypnotized subjects or "somnambulists" perceived hidden facts about their own and others' states of health by means of a "true sensation." Hypnotized subjects were further able to "pre-sense" their future sufferings and the dates of their cures.[4]

Mesmer's followers were prolific, publishing hundreds of tracts and treatises on animal magnetism. Apart from Puységur, his two leading disciples were Nicolas Bergasse, a lawyer from Lyon, and Guillaume Kornmann, a banker from Strasbourg. Bergasse and Kornmann helped Mesmer to found the Société de l'harmonie universelle. Within two years, the society had earned almost 350,000 livres and spawned three provincial societies. By the spring of 1784, mesmerism had become such a craze that it imposed itself on the attention of the king. At his instigation, the Baron de Breteuil, minister of the Department of Paris, appointed two commissions to investigate the practice. One was drawn from the Royal Society of Medicine and the other from the Academy of Sciences and the Faculty of Medicine. The chemist Antoine Lavoisier and Benjamin Franklin, experts on the imponderable fluids of heat and electricity, respectively, chaired the Academy and Faculty commission. The inquiry was a landmark event: the first government investigation of scientific fraud and the earliest instance of formal, psychological testing using what would now be called a placebo sham and a method of blind assessment.

The commissioners began by assuming that mesmeric effects were due not to a nervous fluid, but instead to the faculty of imagination. They devised a method for, in their terms, isolating the action of Mesmer's hypothetical fluid from the action of the patient's imagination. One of their main instruments, which they meticulously described in their report, was a blindfold. They used it, for example, on one of their experimental subjects, a peasant woman with ailing eyes. While she wore the blindfold, one of the commissioners played the role of Deslon, who had agreed to serve as the commission's mesmerist, and pretended to "magnetize" her, successfully causing a mesmeric crisis. In fact, Deslon was in another room attempting to magnetize the gouty and kidney-stone-ridden, yet healthily skeptical, Franklin. The commissioners also had Deslon magnetize subjects from behind a screen, concealed from view, and recorded that in these cases, the treatment had no discernible effect. They concluded that mesmeric effects were due to an as yet largely unknown power: not a nervous fluid, but the power of imagination. (A top secret supplementary report, for the King's eyes only, noted that mesmeric patients were usually women and mesmerists always men. In light of this, the report proposed that so-called "mesmeric crises" were often in fact the manifestations of a different "convulsive state" arising from the latter sex's ability to "arouse" the former.)

Following the roundly negative conclusion of the investigation - both commissions denied the existence of the animal magnetic fluid - Mesmer left Paris and moved about for a period in England and on the continent. During the French Revolution, he lost all the money he had made in France, but afterward, he successfully negotiated with Napoleon's government for a pension. He kept an unprecedentedly low profile for the remainder of his life, which he spent mostly in his native land, and died in Meersburg, near Lake Constance, on 5 March 1815. Despite the investigation results and Mesmer's withdrawal from public life, mesmerism continued apace in the French provinces and across Europe. Its major legacy for the history of psychology was the technique of hypnotism, which would be passed along through the French neurologist Jean-Martin Charcot to another, later Viennese doctor with a materialist theory of mind, Sigmund Freud.

In a letter to Franklin several years after the mesmerism investigation, a fellow commissioner, the doctor Joseph-Ignace Guillotin, recalled their collaboration in the "highly ridiculous affair of animal magnetism."[5] But, within the materialist framework of contemporary natural science, it was the commissioners, and not Mesmer, who made the truly radical and, to many, the ridiculous proposal. Mesmer merely carried materialism to its logical extreme. By doing so, he drove his inquisitors to abandon materialism altogether. They attributed the visceral, physical drama of mesmeric crises to an immaterial cause. What, their many critics demanded, was the imagination? How could it act if not through a material medium? Judging an immaterial power of imagination to be unintelligible and insufficient, the botanist and doctor Antoine-Laurent de Jussieu, having served on the commission from the Royal Society of Medicine, dissented from its final report. (Jussieu sought a material alternative in the active principle of heat.)

It was not Mesmer, then, but his investigators who made mesmerism into the source of a new psychology, a nascent theory of the unconscious that credited the mind with startling powers over the body. Writing on the eve of the Revolution, the commissioners cautioned that the imagination could be manipulated to intoxicate crowds, provoke riots, spur fanaticism. The imagination was, they warned, an "active and terrible power."[6] Mesmer's astral fluid paled in comparison with what his inquisitors conjured from it.


Primary sources

Bailly, Jean-Sylvain. Exposé des experiences qui ont été faites pour l'examen du magnétisme animal. Paris, 1784.

________. "Rapport secret sur le Mesmérisme, ou Magnetisme Animal." 11 August 1784. Reprinted in D.I. Duveen and H.S. Klickstein, "Documentation." Annals of Science 13, no. 1 (March 1957), 42-46.

Bergasse, Nicolas. Considérations sur le magnétisme animal, ou sur la théorie du monde et des êtres organisés. The Hague, 1784.

Jussieu, Bernard de. "Rapport de l'un des commissaires chargés par le Roi de l'examen du magnétisme animal." 12 September 1784. Reprinted in Alexandre Bertrand, Du magnétisme animal en France, et des jugements qu'en portés les sociétés savants (Paris, 1826); 151-206.

Mesmer, Franz Anton. Aphorismes de M. Mesmer: dictés à l'assemblèe de ses élèves, & dans lesquels on trouve ses principes, sa théorie & les moyens de magnetizer. Paris, 1785.

________. De Planetarum influxu, dissertatio physico-medico. Vienna, 1766. Published in translation as "Physical-Medical Treatise in the Influence of the Planets" in Mesmerism (1980), 3-20.

________. Mémoire sur la découverte du magnétisme animal. Paris, 1779. Excerpt published in translation as "Dissertation on the Discovery of Animal Magnetism" in Mesmerism (1980), 43-76.

________. Mémoire de F.A. Mesmer, docteur en médicine, sur ses découvertes. Paris, 1799. Excert published in translation as "Dissertation by F.A. Mesmer, Doctor of Medicine, on his Discoveries" in Mesmerism (1980), 89-130.

________. Le Magnétisme animal. Oeuvres publiés par Robert Amadou. Notes et commentaires par Frank A. Pattie et Jean Vinchon. Paris: Payot. 1971.

________. Mesmerism, A Translation of the Original Scientific Writings of F.A. Mesmer. Translated by George Bloch. Los Altos: William Kaufman, 1980.

________. Précis historique des faits relatifs au magnétisme animal jusqu'en avril 1781. 1781. In Le magnétisme animal (1871), 93-194.

Poissionier, Pierre-Isaac, Nicolas Louis de la Caille et al.. Rapport des commissaires de la Société royale de médecine, nommés par LE ROI pour faire l'examen du Magnétisme animal. Paris, 1784.

Chastenet, Armand Marie-Jacques de, marquis de Puységur. Mémoires pour servir à l'histoire et à l'établissement du magnétisme animal (1786). Edited by Georges Lapassade and Philippe Pédelahore. Bordeaux: Editions Privat, 1986.

Secondary Sources

Crabtree, Adam. From Mesmer to Freud: Magnetic Sleep and the Roots of Psychological Healing. New Haven: Yale University Press, 1993.

Darnton, Robert. Mesmerism and the End of Enlightenment in France. Cambridge: Harvard University Press, 1968.

Duveen, Denis I. and Herbert S. Klickstein. "Benjamin Franklin (1706-1790) and Antoine Laurent Lavoisier (1743-1794)," Part II: "Joint Investigations." Annals of Science 2, no. 4 (December 1955): 271-302.

Kaptchuk, Ted J.. "Intentional Ignorance: A History of Blind Assessment and Placebo Controls in Medicine." Bulletin of the History of Medicine 72, no. 3 (1998): 389-433.

Pattie, Frank A.. Mesmer and Animal Magnetism: A Chapter in the History of Medicine. Edmonston Publishing, Inc, 1994.

Schaffer, Simon. "Self-Evidence." In James Chandler, Arnold I. Davidson, and Harry Hartoonian, eds., Questions of Evidence: Proof, Practice and Persuasion across the Disciplines (Chicago: University of Chicago Press, 1993): 56-91.

Vinchon, Jean. Mesmer et son secret: Textes choisis et presentés par R. de Saussure. Toulouse: Privat, 1971.

Zweig, Stefan. Mental Healers: Franz Anton Mesmer, Mary Baker Eddy, Sigmund Freud. New York: Ungar, 1962 (first publ. 1932).


[1] Bailly et al., Exposé (1784), 4.

[2] Mesmer, Précis (1781), 103, 135.

[3] Mesmer, Dissertation (1799), 120-21.

[4] Mesmer, Précis (1781), 135; Puységur, Mémoires (1786), 74-75.

[5] Joseph-Ignace Guillotin - Benjamin Franklin, 18 June 1787, unpublished manuscript, The Papers of Benjamin Franklin, Yale University Library, online at

[6] Bailly et al., Exposé (1784), 12-16.