In 1784, King Louis XVI convened a Royal Commission to investigate animal magnetism, bringing together some of the most eminent scientists in France, including Benjamin Franklin, then American minister to France, the chemist Antoine Lavoisier, and the physician Joseph-Ignace Guillotin, under the astronomer Jean Sylvain Bailly. The commission, working with Mesmer's own former student Charles d'Eslon since Mesmer himself refused to fully cooperate, designed and ran a series of genuinely innovative blinded experiments, including directing subjects to a supposedly magnetized tree while observing that reported effects occurred regardless of whether the tree had actually been magnetized, among the earliest documented uses of blinding in the history of controlled experiment.
The commission's 1784 report concluded plainly that no physical magnetic fluid could be detected, and that the striking effects observed were produced entirely by the patient's imagination, a finding Bailly summarized by declaring magnetism "no more than an old falsehood." The verdict effectively ended animal magnetism's claim to scientific legitimacy, but not its practice: Mesmer's student the Marquis de Puysegur had already discovered magnetic sleep, an induced trance state, which developed independently into the tradition later renamed hypnotism by James Braid in the 1840s, while the broader idea of an invisible, channelable vital fluid went on to shape later concepts including od and, more loosely, twentieth century notions such as orgone.