Report of Dr. Benjamin Franklin, and other commissioners, charged by the King of France, with the examination of the animal magnetism, as now practised at Paris

In Short

This report documents the official 1784 investigation into "animal magnetism," a medical fad popularized by Franz Mesmer. Claiming that a universal fluid could be manipulated to cure ailments through physical gestures and social suggestion, Mesmer sparked a craze in Paris. The King commissioned a committee—including Benjamin Franklin and Antoine Lavoisier—to test these claims. Through rigorous controlled experiments, the commissioners exposed the practice as a psychological phenomenon driven by expectation and imagination rather than physical reality. It remains a definitive historical landmark in the scientific study of the placebo effect and group hysteria.

The Story

The narrative begins with the rise of Franz Mesmer, a German physician who introduced his theory of "animal magnetism" to Paris. Mesmer argued that a subtle, invisible fluid links the stars, the earth, and all living beings. He claimed this fluid could be accumulated, concentrated, and transferred to heal the sick. His practice, characterized by mysterious "crises"—violent convulsions and sudden lethargy in his patients—became the subject of intense fascination, pitting him against the established medical faculty.

As the fervor reached a fever pitch, the French government intervened. King Louis XVI appointed a high-profile commission to settle the matter. When Mesmer refused to participate, his lead pupil, Charles Deslon, stepped forward to defend the practice. The commissioners observed Deslon’s public sessions, where patients gathered around a "magnetic bucket," many descending into dramatic, synchronized fits of emotion.

The commission’s investigation systematically dismantled the mystical claims of the magnetism. They first tested the practitioners’ ability to produce effects in private, finding that when patients were unaware of the "magnetic" influence, no physical response occurred. They then conducted blind experiments, such as having a patient guess which tree in an orchard had been "magnetized." The patient suffered a convulsive crisis under an ordinary, un-magnetized tree, proving that the patient’s belief—not any physical fluid—was triggering the reaction.

The report concludes that the magnetism is entirely an impostor’s art. The commissioners detail how the "crises" are sustained by social imitation and the power of suggestion. They compare these scenes to the fervor of battle or religious fanaticism, where the sight of one person’s distress triggers a contagious wave of emotion through the assembly. The researchers argue that while imagination can indeed influence the body, the violent, daily repetition of these crises is not a medical cure but a dangerous drain on the patient’s health. By stripping away the scientific veneer of the practice, the commissioners reveal the underlying mechanism to be human psychology. They explicitly warn that such assemblies are essentially contagious, capable of spreading hysteria rather than healing, and they call for an end to the practice to protect public health and sanity.

How It Unfolds

The emergence of a theory The text traces Mesmer’s transition from using loadstones in medicine to his broader, more controversial theory of a universal fluid. It highlights his early failures in Vienna and his subsequent attempt to validate his system in the more receptive climate of Paris.

The commission is established The French crown appoints a diverse group of physicians and scientists, including Benjamin Franklin, to examine the claims. The narrative follows their skepticism as they move from observing public spectacles to conducting controlled, scientific inquiries.

The anatomy of a crisis The commissioners describe the "apartment of crises," where they witness patients in states of intense agitation or profound lethargy. They begin to identify that these symptoms are not spontaneous medical events but are curated by the operator’s touch and presence.

The experiments in imagination The investigators perform rigorous tests, such as blindfolding patients to see if they can identify the "magnetic" force without visual cues. They also test the influence of expectation by telling patients they are being magnetized when they are not, resulting in the same "symptoms."

The verdict The report concludes that animal magnetism has no physical existence. It posits that the entire system relies on the power of the human imagination and mechanical imitation, concluding that the practice is a medical hazard rather than a discovery.

The People

Franz Mesmer stands as the architect of the system, a man convinced of his own discovery but unwilling to submit his claims to the scrutiny of the scientific establishment. His refusal to engage with the committee casts him as a figure of controversy, favoring charismatic performance over empirical verification.

Charles Deslon, Mesmer’s most dedicated pupil, acts as the primary bridge between the master and the commissioners. While he is initially confident that his mentor’s methods are genuine, he becomes the unwitting subject of the commission’s experiments, providing the evidence that eventually disproves his own claims.

Benjamin Franklin and the other commissioners function as the voice of Enlightenment reason. They are not merely observers but active participants who use their standing to demand transparency. They remain unmoved by the dramatic displays of the "magnetic" sessions, maintaining a cool, observational distance that contrasts sharply with the frantic behavior of the patients.

M. Thouret serves as the historian of the group, providing the erudition necessary to place Mesmer’s "discovery" into context. He demonstrates that Mesmer’s principles are not novel, but are recycled versions of ancient, long-debunked ideas.

In Its Own Voice

"It can no longer be concealed that the system of the animal magnetism is to be regarded as an imposture, and it may therefore be asked, why it should be thought necessary to give to the public a translation of papers, which may be thought interesting only to persons who have been witnesses of the imposture."

(The introduction justifies the report's publication as a public service to expose a dangerous deception.)

"The commissioners could not avoid being struck with the difference of the private experiment made upon themselves from the public process. All was calm and silence in the one, all restlessness and agitation in the other."

(The commissioners describe the stark contrast between the quiet of a controlled, skeptical environment and the frantic social atmosphere of Mesmer’s public sessions.)

What It's Really About

At its core, this work is a foundational exploration of the intersection between the mind and the body. It interrogates the limits of self-deception and the way social environments can bypass rational thought. By identifying the "imagination" as the engine of the magnetic crisis, the authors argue for the necessity of skepticism in the face of charismatic authority. The book is an argument for scientific method over anecdotal evidence, showing how easily the human brain can be tricked by expectation, ritual, and the contagious nature of group behavior. It serves as a warning about how quickly a society can abandon reason when a "miracle" offers an easy solution to the complexities of illness.

Why Read It Today

Readers with an interest in the history of science or the evolution of psychological inquiry will find this report fascinating. It captures the exact moment when the modern scientific method began to seriously analyze the human mind as a potential source of "medical" phenomena. To read it is to step into the parlors of 18th-century Paris, feeling the tension between the dying remnants of mystical thinking and the rising tide of the Enlightenment.

The prose is formal, deliberate, and exceptionally precise; those who enjoy the clarity of 18th-century scientific writing will be rewarded. However, the reader should be prepared for the dense, sometimes repetitive structure inherent in an official governmental report, as well as period-typical attitudes toward the "lower classes," who are frequently used as the subjects for the commissioners' experiments. What stays with you is the eerie, modern relevance of the findings. The authors describe social dynamics—such as the way people mimic the behavior of those around them in a crowd—that feel strikingly contemporary. It is a sobering, elegant reminder of how fragile our grip on reality can be when our imagination is encouraged to run wild, and it remains a vital text for understanding the origins of modern skepticism.