The commissioners of the Faculté de médecine and the Académie des sciences—with the exception of Franklin—met in Paris on Wednesday, August 11, to sign the report of their four-month investigation. Franklin, unable to travel, had signed in advance, having received the pristine manuscript in a locked box two days earlier with instructions to keep his signature small enough to leave room for the others.7 As head of the commission, his signature came first.

It is not known when Franklin was chosen to head this joint commission, but it may have been at its initial meeting on May 8. Though the discussions were confidential, news of the appointment quickly circulated. Mesmer sent his May 14 letter of protest to Franklin individually, declaring him to be the head of the commission. (Franklin’s reply did not deny it.) A week later Lafayette, writing on Mesmer’s behalf, appealed to the man whom the world considered to be the commission’s “president.”8

The American minister’s prestige and reputation as both a scientist and a diplomat, as well as his being the sole foreign member, must have made him an obvious choice to lead what might have been a contentious coalition. His election to the Académie des sciences had been based on his having proved the existence of a supremely powerful, invisible force—atmospheric electricity— whose therapeutic applications had been compared to magnetic treatments and were a promising field of study. He could be seen as impartial, having never taken part in any previous attempt to investigate Mesmer or Deslon. The views he had recently expressed about Mesmer’s “cures” which he guessed were psychological in nature, had been almost benign.9 Moreover, although the members of the Faculty had initially resisted the government’s injunction to work with members of the Academy, none of them seemed opposed to collaborating with Benjamin Franklin. As Lavoisier wrote of the commissioners, “Leurs lumières, leurs qualités morales, le nom du célèbre Franklin placé à la tête, tout, dans cette Commission, paraissait propre à imprimer le respect et a inspirer la confiance.”1 If the government’s purpose in expanding the commission beyond the Faculty of Medicine was to instill public confidence in its findings,2 then the commissioners could have chosen no better person to represent them.

What were Franklin’s actual contributions.? We know that he hosted experiments at Passy and was himself magnetized. Finding travel prohibitively difficult, he did not attend the meetings and experiments that took place in Paris, which accounted for more than half of the commission’s work. He followed its progress, however, as recorded in the confidential log (“registre”) that was sent to him periodically for his review and signature. He must also have been briefed by his friend, neighbor, and co-commissioner Jean-Baptiste Le Roy.

As the “registre” has been lost, it is all but impossible to tease out the individual contributions of any of the commissioners. The notes of only one, Lavoisier, survive; from these writings, it is clear that he designed at least some of the key experiments. It seems unlikely that Franklin did not have a hand in designing experiments as well. Without the commission’s log, however, none of the internal discussions and debates, or even the dates of individual experiments, is retrievable. The only surviving account of the commissioners’ work is their official report, which was careful to present the group as a unified, cooperative body. The appointment of a “president” was never mentioned. The members’ names were listed in the opening paragraph, but thereafter they were characterized almost exclusively in the collective third person. An individual was mentioned only when his house was the scene of an experiment (Franklin’s residence being the most frequent of these), and, in one case, when a renowned ophthalmologist was described as examining a patient’s diseased eye as a means of distracting her attention as she was being magnetized.3 Otherwise, the commissioners were anonymous. They proceeded as a group, made decisions “unanimement,” and in presenting their conclusions spoke with a “voix unanime.”4 Even the order of their signatures signaled their integration: the five members of the Academy and the four members of the Faculty signed in strict alternation. When Bailly addressed the Académie des sciences on September 4 about the commission’s work, he stressed its unity. Their efforts had been motivated by a mutual desire for truth, and the results belonged to all of them: “rien n’a été distingue, le travail appartient à tous … nous avons été toujours unis, toujours unanimes.”5

The eagerly anticipated Rapport des commissaires chargés par le Roi, de l’examen du magnétisme animal was published by the Imprimerie royale around August 216 and, at 66 pages, was the size of a small book. A preview of its conclusion was made public on August 20 in the Mémoires secrets. Reminding readers that the commissioners had investigated Deslon, not Mesmer, the article reported that they had found animal magnetism to be “une invention illusoire, vaine & funeste.”7

Knowing that their report would be published and that the task of convincing the public lay wholly in their hands, the authors produced an account that was both scientifically sound and accessible, making for compelling reading. Chronology was unimportant; few dates were specified. The rationale for every decision and the details of every experiment, however, were explained in terms that anyone could understand. Rapport des commissaires was immediately reprinted in France by private publishers. Before the year was out, an English translation was issued in London by Joseph Johnson, who placed Franklin’s name in the title and identified him in the introduction as the head of the commission: Report of Dr. Benjamin Franklin, and other Commissioners, Charged by the King of France, with the Examination of the Animal Magnetism, as now Practiced at Paris.8 The report would become famous for the originality and rigor of the experiments, which led systematically to conclusions that the authors considered irrefutable.

On the advice of Breteuil, the commissioners reserved some of their observations for a second, secret report, also signed on August 11, which would be for the king’s eyes only.9 Its message was blunt: the practice of animal magnetism was a threat not only to health, as the official report had stated, but also to morality, especially in the case of weak, virtuous women. The commissioners offered a medical explanation of why the nerves and imaginations of women were more easily excited than those of men. They provided an explicit description of a certain kind of prolonged “convulsion” that resulted not from the alleged healing power of animal magnetism but rather from the close physical contact and mutual arousal of male magnetizers and female patients who did not fully understand what was being done to them.1 Deslon himself had admitted, under interrogation by Lenoir, how easy it would be to abuse a woman in such a state. Many women had been in treatment for years without being cured. Most of them were not ill to begin with, but had been drawn to the clinic for the amusement it provided, attending regularly as a relief from boredom. Around the tub, the ease with which symptoms spread from person to person was striking. The commissioners reiterated the health risks of inducing full-blown crises, a dangerous practice that any responsible physician would shun. They implied the possibility that magnetic seances were a deliberate fraud. The uniformly critical tone of this private document was in stark contrast to the scrupulously evenhanded voice of the official report.

In the end, the commissioners of the Faculty of Medicine obtained what they had initially requested in their April 3 letter to Breteuil:2 a group of elite scientists had undertaken a systematic, logical series of experiments to prove whether animal magnetism existed. Contrary to their original proposal, however, their own investigation had not waited until after the academicians’ work had concluded; they had become integral participants. The scientists of the Academy had insisted on this, deeming the doctors’ expertise indispensable. In a statement that appears to have been read at one of the commission’s first sessions, Lavoisier eloquently outlined the distinct roles of scientists versus doctors, and proposed a way to proceed.3

To all outward appearances, the group coalesced quickly. Franklin’s hospitality at Passy seemed to have helped foster the spirit of cooperation that ultimately characterized the Faculty/Academy commission. Its first meeting was convened around his table. The experiments performed at Passy were preceded by dinners at that same table, to which all the participants, from the investigators down to the humblest patients, were invited. Even after the report was published Franklin continued to host the commissioners, and these new friendships were further cultivated.4 His scientific contributions to the investigation may never be known, but Franklin’s role as head of the commission was rendered iconic when the print Le Magnétisme dévoilé depicted him leading the charge against mesmerist superstition and vice.5

⟨Paris, August 11, 1784, in French: On March 12 the king appointed four physicians of the Faculty of Medicine—Borie, Sallin, d’Arcet, and Guillotin—to examine and report on animal magnetism as practiced by Deslon. At their request, the king appointed five members of the Academy of Sciences to join them: Franklin, Le Roy, Bailly, Bory, and Lavoisier. When Borie died at the outset of their work, the king appointed Ma-jault to replace him.

The agent that Mesmer claims to have discovered is defined, in his own words, this way:6 it is a universal fluid that facilitates a mutual influence among celestial bodies, the earth, and all living beings, and exhibits two distinct, opposite poles, like those of a magnet. Its effect can be transmitted from one animate or inanimate body to another, even over long distances, without an intermediary. The effect is intensified when the fluid is reflected in a mirror and transmitted through sound. Magnetic fluid can be collected, concentrated, and transported. In the human body it affects the nerves particularly. Animal magnetism can cure nervous disorders, improve the effect of medications, and induce salutary crises. It enables physicians to assess an individual’s health and determine with certainty the cause and course of even the most complicated diseases. Magnetism provides a universal means of healing and preserving mankind.

Deslon endorses all of Mesmer’s principles. On May 9 the commissioners and Lenoir, lieutenant of police, assembled at Deslon’s house and listened to him read a memoir. He claimed that there is one nature, one disease, and one cure: animal magnetism. He then demonstrated how he directed magnetic fluid in his patients. Deslon pledged to cooperate with the commissioners to ascertain the existence of animal magnetism, to make known his knowledge of it, and to prove the usefulness of animal magnetism in the curing of disease.

The commissioners repeatedly visited Deslon’s clinic and observed group therapy sessions around a baquet, a circular, covered wooden tub from which protrude bent, movable iron rods.7

Patients are arranged in rows around this tub and press an iron rod to their afflicted body part, while holding each other by the thumbs or being tied together with a cord. In the corner sits a pianoforte on which different kinds of melodies are played, occasionally accompanied by singing. The magnetizer holds a metal rod 10 to 12 inches long. Deslon told the commissioners that the rod and music both conduct magnetism; that the rope and chain of thumbs both augment the effect; and that the inside of the tub concentrates magnetism. Patients receive magnetism simultaneously by these means. They are also directly magnetized when the magnetizer passes a finger and metal rod in front of their face or around their afflicted part, stares into their eyes, and applies pressure with his hands and fingers to the lower abdominal area, maintaining contact for as much as several hours.

While some patients remain calm, the more common effect of this treatment is what is called, in animal magnetism, the crisis: fits of violent convulsions and seizures that can last for hours, accompanied by screams and laughter, followed by exhaustion and lethargy. These so-called crises are considered salutary. The power wielded by the magnetizer over his patients is extraordinary. Most patients who experience crises are women, and the crises appear to be contagious among them.

After the commissioners observed the effects of these magnetic treatments, their next task was to determine the causes and to search for proof of the existence and utility of magnetism. The question of existence had to come first, for animal magnetism can certainly exist without being useful, but it cannot be useful if it does not exist.8 Deslon insisted that the commissioners investigate the curative powers of magnetism, but they did not believe that they had to do so. Because magnetic fluid was acknowledged to be undetectable by the senses, and the commissioners considered any gradual improvement of symptoms to be inconclusive evidence of the efficacy of any particular treatment,9 they determined to focus on immediate, physical effects attributable to no other cause than animal magnetism.

The commissioners resolved to perform the first experiments on themselves, so that they could experience the sensations. They agreed unanimously to conduct these trials as a group, in private, so that they could freely discuss their observations. Deslon set up for them a separate room with a tub, and they went there once a week; they were magnetized by either Deslon or one of his disciples for two and a half hours each time. None felt any symptoms ascribable to animal magnetism. In order to test whether sequential days of treatment would make a difference, some commissioners went three days in a row, but the effect was the same.

The commissioners next determined to experiment on subjects who were actually sick, chosen from the lower classes. This second experiment was conducted at Franklin’s home.

Sept malades ont été rassemblés à Passy chez M. Franklin; ils ont été magnétisés devant lui & devant les autres Commissaires par M. Deslon.

La veuve Saint-Amand, asthmatique, ayant le ventre, les cuisses & les jambes enflees; & la femme Anseaume, qui avoit une grosseur à la cuisse, n’ont rien senti; le petit Claude Renard, enfant de six ans, scrofuleux, presque étique, ayant le genou gonflé, la jambe fléchie & l’articulation presque sans mouvement, enfant intéressant & plus raisonnable que son âge ne le comporte, n’a également rien senti, ainsi que Geneviève Leroux, âgée de neuf ans, attaquée de convulsions & d’une maladie assez semblable à celle que l’on nomme chorea sancti Viti. François Grenet a éprouvé quelques effets; il a les yeux malades, particulièrement le droit, dont il ne voit presque pas, & où il a une tumeur considérable. Quand on a magnétisé l’œil gauche en approchant, en agitant le pouce de près & assez long-temps, il a éprouvé de la douleur dans le globe de l’œil, & l’œil a larmoyé. Quand on a magnétisé l’œil droit, qui est le plus malade, il n’y a rien senti; il a senti la même douleur à l’œil gauche, & rien par-tout ailleurs.

La femme Charpentier, qui a été jetée à terre contre une poutre, par une vache, il y a deux ans, a éprouvé plusieurs suites de cet accident; elle a perdu la vue, l’a recouvrée en partie, mais elle est restée dans un état d’infirmités habituelles; elle a déclaré avoir deux descentes, & le ventre d’une sensibilité si grande, qu’elle ne peut supporter les cordons de la ceinture de ses jupes: cette sensibilité appartient à des nerfs agacés & rendus très-mobiles; la plus légère pression faite dans la région du ventre, peut déterminer cette mobilité & produire des effets dans tout le corps par la correspondance des nerfs.

Cette femme a été magnétisée comme les autres, par l’application & par la pression des doigts; la pression lui a été douloureuse: ensuite en dirigeant le doigt vers la descente, elle s’est plainte de douleur à la tête; le doigt étant placé devant le visage, elle a dit qu’elle perdoit la respiration. Au mouvement réitéré du doigt de haut en bas, elle avoit des mouvemens précipités de la tête & des épaules, comme on en a d’une surprise mêlée de frayeur, & semblables à ceux d’une personne à qui on jetteroit quelques gouttes d’eau froide au visage. Il a semblé qu’elle éprouvoit les mêmes mouvemens ayant les yeux fermés. On lui a porté les doigts sous le nez en lui faisant fermer les yeux, & elle a dit qu’elle se trouveroit mal si on continuoit. Le septième malade, Joseph Ennuyé, a éprouvé des effets du même genre, mais beaucoup moins marqués.

Sur ces sept malades, il y en a quatre qui n’ont rien senti & les trois autres ont éprouvé des effets. Ces effets méritoient de fixer l’attention des Commissaires, & demandoient un examen scrupuleux.

The third series of experiments was conducted with patients chosen from the aristocracy. In one experiment, four of them, two women and two men, were admitted to the commissioners’ private tub; two felt minor effects. Other patients were tested in other circumstances. Deslon magnetized one commissioner suffering from acute migraine, but the pain did not abate. The doctor also went to Passy to magnetize Franklin and members of his household.

M. Franklin, quoique ses incommodités l’aient empêché de se transporter à Paris, & d’assister aux expériences qui y ont été faites, a été lui-même magnétisé par M. Deslon, qui s’est rendu chez lui à Passy. L’assemblée étoit nombreuse; tous ceux qui étoient présens ont été magnétises. Quelques malades qui avoient accompagné M. Deslon, ont ressenti les effets du Magnétisme, comme ils ont coutume de les ressentir au traitement public; mais Mme de B**, M. Franklin, ses deux Parentes, son Secrétaire, un Officier Américain, n’ont rien éprouvé, quoiqu’une des Parentes de M. Franklin fût convalescente, & l’Officier Américain alors malade d’une fièvre réglée.1

Collecting and analyzing the data gathered so far, the commissioners concluded that magnetic treatments had the capacity neither to detect illnesses nor to alleviate them. The fact that the most pronounced symptoms were experienced by lower-class patients, who were presumed to be more credulous and more eager to please their examiners, while the more educated and skeptical subjects felt little or nothing, led them to suspect that the patient’s imagination played a part in producing symptoms.

At this stage of the investigation, the commissioners learned that a medical doctor named Jumelin2 was conducting experiments with animal magnetism at the home of the dean of the Faculty. Though Jumelin was not a disciple of Mesmer or Deslon, he magnetized patients as they did, using his fingers and an iron rod and laying his hands on affected parts of the body. He did not, however, make any distinction between poles. Jumelin agreed to perform a series of experiments (the fourth series) at the home of commissioner Majault. First, he magnetized eleven patients, eight men and three women. As only one woman felt effects—intense heat directly beneath where Jumelin’s hand floated above her body—the commissioners proposed blindfolding her so that she could not see where the magnetism was being directed. Under those conditions, she felt no effects in the places being magnetized. They removed the blindfold and had Jumelin place his hand on her abdomen; then, she again felt heat and even fainted. The blindfold was reinstated, and the commissioners led her to believe that Jumelin was magnetizing her once more (which he was not). She felt the same effects, with the same intensity. After some time, Jumelin was silently directed to magnetize her over her stomach and back; she felt nothing. These experiments led the commissioners to conclude that the method of magnetizing and the distinction between poles were irrelevant. They then tested the supposition that the patients’ reactions were caused by their imaginations, by having Jumelin conduct similar experiments (the fifth series) on other patients. Once again the blindfolded patients felt sensations according to where they believed the magnetism to be directed.

In the sixth series of experiments, conducted at M. Jumelin’s home, the commissioners used his servant to test a blindfold they had designed, which, being padded with goose down, was comfortable and admitted no light whatsoever. The commissioners, especially the doctors among them, conducted an “infinite” number of experiments on patients who either were or were not being magnetized, with and without their knowledge. The results were always the same: effects were felt only when patients believed that magnetism was being applied, and patients could induce these sensations in themselves.3

Having determined that imagination, on its own, can produce sensations and make a patient feel pain and heat, the commissioners wanted to test whether the imagination by itself was powerful enough to induce actual crises. The seventh, eighth, and ninth experiments, designed to provide an answer, were performed at Passy on different days with subjects chosen by Deslon: a boy and two women.

Lorsqu’un arbre a été touché suivant les principes & la méthode du Magnétisme, toute personne qui s’y arrête doit éprouver plus où moins les effets de cet agent; il en est même qui y perdent connoissance où qui y éprouvent des convulsions. On en parla à M. Deslon, qui répondit que l’expérience devoit réussir pourvu que le sujet fût fort sensible, & on convint avec lui de la faire à Passy, en présence de M. Franklin.4 La nécessité que le sujet fût sensible, fit penser aux Commissaires que pour rendre l’expérience décisive & sans réplique, il falloit qu’elle fût faite sur une personne choisie par M. Deslon, & dont il auroit éprouvé d’avance la sensibilité au Magnétisme. M. Deslon a donc amené avec lui un jeune homme d’environ douze ans, on a marqué dans le verger du jardin, un abricotier bien isolé, & propre à conserver le Magnétisme qu’on lui auroit imprimé. On y a mené M. Deslon seul, pour qu’il le magnétisât, le jeune homme étant resté dans la maison & avec une personne qui ne l’a pas quitté. On auroit desiré que M. Deslon ne fût pas présent à l’expérience, mais il a déclaré qu’elle pourroit manquer s’il ne dirigeoit pas sa canne & ses regards sur cet arbre, pour en augmenter l’action. On a pris le parti d’éloigner M. Deslon le plus possible, & de placer les Commissaires entre lui & le jeune homme, afin de s’assurer qu’il ne feroit point de signal, & de pouvoir répondre qu’il n’y avoit point eu d’intelligence. Ces précautions, dans une expérience qui doit être authentique, sont indispensables sans être offensantes.

On a ensuite amené le jeune homme, les yeux bandés, & où l’a présenté successivement à quatre arbres qui n’étoient point magnétisés, en les lui faisant embrasser, chacun pendant deux minutes, suivant ce qui avoit été réglé par M. Deslon lui-même.

M. Deslon présent, & à une assez grande distance, dirigeoit sa canne sur l’arbre réellement magnétisé.

Au premier arbre, le jeune homme interrogé au bout d’une minute, a déclaré qu’il suoit à grosses gouttes; il a toussé, craché, & il a dit sentir une petite douleur sur la tête; la distance à l’arbre magnétisé étoit de vingt-sept pieds.

Au second arbre, il se sent étourdi, même douleur sur la tête; la distance étoit de trente-six pieds.

Au troisième arbre, l’étourdissement redouble ainsi que le mal de tête; il dit qu’il croit approcher de l’arbre magnétisé; il en étoit alors environ à trente-huit pieds.

Enfin au quatrième arbre non magnétisé, & à vingt quatre pieds environ de distance de l’arbre qui l’avoit été, le jeune homme est tombé en crises; il a perdu connoissance, ses membres se sont roidis, & on l’a porté sur un gazon voisin, où M. Deslon lui a donné des secours & l’a fait revenir.

Le résultat de cette expérience est entièrement contraire au Magnétisme. M. Deslon a voulu expliquer le fait, en disant que tous les arbres sont magnétisés par eux-mêmes, & que leur Magnétisme étoit d’ailleurs renforcé par sa présence. Mais alors une personne sensible au Magnétisme, ne pourroit hasarder d’aller dans un jardin sans risquer d’avoir des convulsions; cette assertion seroit démentie par l’expérience de tous les jours. La présence de M. Deslon n’a rien fait de plus que ce qu’elle a fait dans le carrosse où le jeune homme est venu avec lui, placé vis-à-vis de lui, & où il n’a rien éprouvé. Si le jeune homme n’eût rien senti, même sous l’arbre magnétisé, on auroit pu dire qu’il n’étoit pas assez sensible, du moins ce jour-là: mais le jeune homme est tombé en crise sous un arbre qui n’étoit pas magnétisé; c’est par conséquent un effet qui n’a point de cause physique, de cause extérieure, & qui n’en peut avoir d’autre que l’imagination. L’expérience est donc tout-à-fait concluante: le jeune homme savoit qu’on le menoit à l’arbre magnétisé, son imagination s’est frappée, successivement exaltée, & au quatrième arbre elle a été montée au degré nécessaire pour produire la crise.

D’autres expériences viennent à l’appui de celle-ci, & fournissent le même résultat. Un jour que les Commissaires se sont réunis à Passy chez M. Franklin, & avec M. Deslon, ils avoient prié ce dernier d’amener avec lui des malades, & de choisir dans le traitement des pauvres, ceux qui seroient le plus sensibles au Magnétisme. M. Deslon a amené deux femmes; & tandis qu’il étoit occupé à magnétiser M. Franklin & plusieurs personnes dans un autre appartement, on a séparé ces deux femmes, & on les a placées dans deux pièces différentes.

L’une la femme P**, a des taies sur les yeux; mais comme elle voit toujours un peu, on lui a cependant couvert les yeux du bandeau décrit ci-dessus. On lui a persuadé qu’on avoit amené M. Deslon pour la magnétiser: le silence étoit recommandé, trois Commissaires étoient présens, l’un pour interroger, l’autre pour écrire, le troisième pour représenter M. Deslon. On a eu l’air d’adresser la parole à M. Deslon, en le priant de commencer, mais on n’a point magnétisé la femme; les trois Commissaires sont restés tranquilles, occupés seulement à observer ce qui alloit se passer. Au bout de trois minutes la malade a commencé à sentir un frisson nerveux; puis successivement elle a senti une douleur derrière la tête, dans les bras, un fourmillement dans les mains, c’est son expression; elle se roidissoit, frappoit dans ses mains, se levoit de son siège, frappoit des pieds: la crise a été bien caractérisée. Deux autres Commissaires placés dans la pièce a côté, la porte fermée, ont entendu les battemens de pieds & de mains, & sans rien voir, ont été les témoins de cette scène bruyante.

Ces deux Commissaires étoient avec l’autre malade, la demoiselle B**, attaquée de maux de nerfs. On lui a laissé la vue libre & les yeux découverts; on l’a assise devant une porte fermée, en lui persuadant que M. Deslon étoit de l’autre côté, occupé à la magnétiser. Il y avoit à peine une minute qu’elle étoit assise devant cette porte, quand elle a commencé à sentir du frisson; après une autre minute, elle a eu un claquement de dents, & cependant une chaleur générale; enfin après une troisiéme minute, elle est tombee tout-à-fait en crise. La respiration étoit précipitée; elle étendoit les deux bras derrière le dos, en les tordant fortement, & en penchant le corps en devant: il y a eu tremblement général de tout le corps; le claquement de dents est devenu si bruyant, qu’il pouvoit être entendu de dehors; elle s’est mordu la main, & assez fort pour que les dents y soient resté marquées.

Il est bon d’observer qu’on n’a touché en aucune manière ces deux malades; on ne leur a pas même tâté le pouls, afin qu’on ne pût pas dire qu’on leur avoit communiqué le Magnétisme, & cependant les crises ont été complètes. Les Commissaires qui ont voulu connoître l’effet du travail de l’imagination, & apprécier la part qu’elle pouvoit avoir aux crises du Magnétisme, ont obtenu tout ce qu’ils desiroient. Il est impossible de voir l’effet de ce travail plus à découvert & d’une manière plus évidente, que dans ces deux expériences. Si les malades ont déclaré que leurs crises sont plus fortes au traitement, c’est que l’ébranlement des nerfs se communique, & qu’en général toute émotion propre & individuelle est augmentée par le spectacle d’émotions semblables.

The tenth and eleventh experiments were performed on the highly susceptible dame P***, who suffered from filmy eyes and who, at Passy, had fallen into a crisis. This time she was tested at the home of Lavoisier, with Deslon present, to determine the extent to which her imagination was engaged. After recovering from the swoon she experienced when entering the house, she was shown a group of cups filled with liquid and asked to select the one that had been magnetized. She fell into a crisis after having been shown four non-magnetized cups, but afterwards, when given a cup of water to drink that had been magnetized by Deslon himself, she felt nothing. Next, Majault examined the film on her eyes while, unbeknownst to her, the magnetized cup was held for twelve minutes behind her head. Distracted and comforted by the eye exam, she was calmer than at any other time.

The twelfth experiment tested the power of sight to stimulate the imagination. One of Jumelin’s patients, who had lost the power of speech when he magnetized her, agreed to be magnetized again at his house in the presence of the commissioners. Her extreme reaction could be reproduced only when she was able to see Jumelin.

The thirteenth experiment explored the role of the magnetizer’s gaze, which, it was agreed, was far more powerful than any other kind of sign or gesture. A new patient at Deslon’s clinic, coming out of a crisis, was transfixed by her magnetizer’s gaze, and reported that she carried it in her mind’s eye for three days, asleep or awake.

The fourteenth and fifteenth experiments tested whether animal magnetism could produce any effects without the imagination being engaged. As magnetic fluid was said to pass through walls and heavy wooden doors, and as Deslon himself had asserted that it passed through paper, the commissioners removed a door between two chambers and replaced it with a paper partition. From behind that partition, at a distance of eighteen inches, one of the commissioners magnetized Mlle. B** for thirty minutes without her knowledge, as she chatted with the others. Although when magnetized at Passy she had fallen into a violent crisis within minutes, this time she felt nothing. The magnetizer then entered her chamber, stood in front of her at precisely the same distance, and magnetized her in a manner that, unbeknownst to her, should have produced no effects, according to Mesmer’s doctrine of polarity. Within minutes she fell into a convulsive crisis complete with headache, hiccups, teeth-chattering, foot-tapping, twisting limbs, and pain in her lower back.

The sixteenth experiment, also conducted on Mlle. B**, proved that imagination could end a crisis as well as instigate it. As the magnetizer told her that it was time to stop, he crossed his index fingers in a way that should have continued the flow of magnetism exactly as before. He then told her that each of her symptoms would abate. Within only three minutes, his voice directing her imagination, the pain in her head, neck, chest, and arms disappeared.

Having proven that animal magnetism did not exist and that all the symptoms they had observed were attributable to the imagination, the commissioners discussed the physical effects and how they were augmented in group sessions. They pointed out the potentially harmful consequences of prolonged pressure, either light or deep, on the colon, diaphragm, stomach, and uterus during magnetic treatments. They noted the phenomenon of mutual incitement and imitation of symptoms in group sessions, particularly among women, that often led to the proliferation of crises.5 And they discussed how hysterical symptoms could become habitual, and could be easily induced by the repetition of certain triggers.

The real causes of the effects ascribed to animal magnetism, they determined, were touch, imagination, and imitation. Among these, imagination was the most important. Even Deslon agreed in some measure with this assessment.

M. Deslon ne s’éloigne pas de ces principes. Il a déclaré dans le Comité tenu chez M. Franklin le 19 juin, qu’il croyoit pouvoir poser en fait que l’imagination avoit la plus grande part dans les effets du Magnétisme animal; il a dit que cet agent nouveau n’étoit peut-être que l’imagination elle-même, dont le pouvoir est aussi puissant qu’il est peu connu: il assure avoir constamment reconnu ce pouvoir dans le traitement de ses malades, & il assure également que plusieurs ont été ou gueris ou infiniment soulagés. Il a observe aux Commissaires que l’imagination ainsi dirigee au soulagement de l’humanite souffrante, seroit un grand bien dans la pratique de la Medecine (h);6 & persuadé de cette vérité du pouvoir de l’imagination, il les a invités à en étudier chez lui la marche & les effets. Si M. Deslon est encore attaché à la première idée que ces effets sont dûs a Taction d’un fluide, qui se communique d’individu à individu par l’attouchement ou par la direction d’un conducteur, il ne tardera pas à reconnoître avec les Commissaires qu’il ne faut qu’une cause pour un effet, & que puisque l’imagination suffit, le fluide est inutile. Sans doute nous sommes entoures d’un fluide qui nous appartient, la transpiration insensible forme autour de nous une atmosphere de vapeurs egalement insensibles; mais ce fluide n’agit que comme les atmosphères, ne peut se communiquer qu’infiniment peu par l’attouchement, ne se dirige ni par des conducteurs, ni par le regard, ni par l’intention, n’est point propagé par le son, ni réfléchi par les glaces, & n’est susceptible dans aucun cas des effets qu’on lui attribue.

Finally, the commissioners considered whether the crises and convulsions produced around the tub could ever be useful in curing patients. They concluded that they could not; these convulsions were violent and harmful, capable of causing lasting physical and neurological damage. Wise doctors attempted to quiet such convulsions, not induce them. Suffering them regularly could only be fatal.

The commissioners unanimously concluded that animal magnetism did not exist and a belief therein constituted a regression to the superstitions of a less enlightened age.

Les Commissaires ayant reconnu que ce fluide magnétique animal ne peut être apperçu par aucun des nos sens, qu’il n’a eu aucune action, ni sur eux-mêmes, ni sur les malades qu’ils lui ont soumis; s’étant assurés que les pressions & les attouchemens occasionnent des changemens rarement favorables dans l’économie animale; & des ébranlemens toujours fâcheux dans l’imagination; ayant enfin démontré par des expériences décisives que l’imagination sans Magnétisme produit des convulsions, & que le Magnétisme sans l’imagination ne produit rien; ils ont conclu d’une voix unanime, sur la question de l’existence & de l’utilité du Magnétisme, que rien ne prouve l’existence du fluide magnétique animal; que ce fluide sans existence est par consequent sans utilité; que les violens effets que l’on observe au traitement public, appartiennent a l’attouchement, à l’imagination mise en action, & à cette imitation machinale qui nous porte malgre nous a repeter ce qui frappe nos sens. Et en même temps ils se croient obligés d’ajouter, comme une observation importante, que les attouchemens, l’action répétée de l’imagination, pour produire des crises, peuvent être nuisibles; que le spectacle de ces crises est également dangereux à cause de cette imitation dont la nature semble nous avoir fait une loi; & que par conséquent tout traitement public où les moyens du Magnétisme seront employés, ne peut avoir à la longue que des effets funestes (i).7

A Paris, ce onze Août mil sept cent quatre-vingt quatre. Signés, B. Franklin, Majault, le Roi, Sallin, Bailly, d’Arcet, de Bory, Guillotin, Lavoisier.⟩