Mesmer was born in the village of Iznang, Swabia. After studying at the Jesuit universities of Dillingen and Ingolstadt, he took up the study of medicine at the University of Vienna in 1759. In 1766 he published a doctoral dissertation with the Latin title De planetarum influxu, which discussed the influence of the moon and the planets on the human body and on disease. Evidence assembled by Frank A. Pattie suggests that Mesmer plagiarized his dissertation from a work by Richard Mead (1673-1754).
Soon after receiving his degree, Mesmer married a wealthy widow and established himself as a physician in Vienna. He lived on a splendid estate and patronised the arts. When court intrigue prevented the performance of Bastien und Bastienne, the first opera composed by the twelve-year-old musical prodigy Wolfgang Amadeus Mozart, Mesmer offered his own gardens for the production. Mozart later immortalized his former patron by including a joking reference to Mesmer in his opera Cosi fan tutte.
In 1774 he used a magnet to produce an "artificial tide" in a patient. Mesmer had her swallow a preparation containing iron, and then attached magnets to various parts of her body. She reported feeling streams of a mysterious fluid running through her body and was relieved of her symptoms for several hours. Mesmer did not believe that the magnets had achieved the cure on their own. He felt that he had contributed animal magnetism, which had accumulated in his own body, to her. He soon stopped using magnets as a part of his treatment.
In 1775 Mesmer was invited to give his opinion before the Munich Academy of Sciences on the exorcisms carried out by Johann Joseph Gassner (1727-1779), a priest and healer. Mesmer said that while Gassner was sincere in his beliefs, his cures were due to the fact that he possessed a high degree of animal magnetism. This confrontation between Mesmer's secular ideas and Gassner's religious beliefs marked the end of Gassner's career as well as, according to Henri Ellenberger, the emergence of dynamic psychiatry.
The scandal which followed Mesmer's unsuccessful attempt to treat the blindness of an 18-year-old musician, Maria Theresa Paradis, led him to leave Vienna in 1777. The following year Mesmer moved to Paris, rented an apartment in a part of the city preferred by the wealthy and powerful and established a medical practice. Paris soon divided into those who thought he was a charlatan, who had been forced to flee from Vienna, and those who thought he had made a great discovery.
In his first years in Paris, Mesmer tried and failed to get either the Royal Academy of Sciences or the Royal Society of Medicine to provide official approval for his doctrines. He found only one physician of high professional and social standing, Charles d'Eslon, to become a disciple. In 1779, with d'Eslon's encouragement, Mesmer wrote an 88-page book Mémoire sur la découverte du magnétisme animal, to which he appended his famous 27 Propositions. These propositions outlined his theory at that time.
According to d'Eslon, Mesmer understood health as the free flow of the process of life through thousands of channels in our bodies. Illness was caused by obstacles to this flow. Overcoming these obstacles and restoring flow produced crises, which restored health. When Nature failed to do this spontaneously, contact with a conductor of animal magnetism was a necessary and sufficient remedy. Mesmer aimed to aid or provoke the efforts of Nature. To cure an insane person, for example, involved causing a fit of madness. The advantage of magnetism involved accelerating such crises without danger.
Mesmer treated patients both individually and in groups. With individuals he would sit in front of his patient with his knees touching the patient's knees, pressing the patient's thumbs in his hands, looking fixedly into the patient's eyes. Mesmer made "passes", moving his hands from patients' shoulders down along their arms. He then pressed his fingers on the patient's hypochondriac region (the area below the diaphragm), sometimes holding his hands there for hours. Many patients felt peculiar sensations or had convulsions that were regarded as crises and supposed to bring about the cure.
By 1780 Mesmer had more patients than he could treat individually and he established a collective treatment known as the baquet. An English physician, who observed Mesmer, described the treatment as follows:
The commission conducted a series of experiments aimed, not at determining whether Mesmer's treatment worked, but whether he had discovered a new physical fluid. The commission concluded that there was no evidence for such a fluid. Whatever benefit the treatment produced was attributed to "imagination." In 1785 Mesmer left Paris. His activities over the next twenty years are largely unknown.
Among Mesmer's followers was Armand-Marc-Jacques Chastenet, Marquis de Puységur (1751-1825), who discovered induced or artificial somnambulism.
Mesmer's name is also the basis of the word mesmerization.