startling theories of illness and disturbing and erotically tinged methods of treatment.

His patients, known as sommambules, were described by one observer as mostly “hysterical bourgeois women,” and he treated them in group “magnetic séances.” Like many 18th-century intellectuals, Mesmer was interested in alchemy and astrology, and he cloaked his treatments in the symbols of these already-contested fields. The sommambules sat holding hands around a large wooden tub filled with powdered glass and magnetized iron filings. They were relaxed and brought into rapport by the sweet haunting tones of the glass armonica, an instrument invented, coincidentally, by Franklin. The armonica was played behind a curtain covered with astrological symbols, and it produced ethereal sounds that were the era's equivalent of modern electronic-consciousness music. After a while, Mesmer, cloaked by a long purple robe, would sweep into the room. The effect was dramatic. In a performance that was a cross between that of a modern entertainment hypnotist and a psychotherapist, he would talk the sommambules into a deep trance and give them healing suggestions. Then he would touch them with a white metal wand, sometimes rubbing them. And finally, he would command them to awaken, rested and cured. It often worked, and Mesmer’s success made him popular with laypeople and feared by the medical establishment.

How Mesmer discovered the fundamentals of hypnotism and stumbled onto the rudiments of the psychophysical self-regulation that lies at the core of such modern treatments as psychotherapy, hypnotism, and biofeedback is unknown. It may be that he just observed that a relaxed trance state produced a kind of anesthesia that gave subjects physiological control over their bodies and minds. However it happened, he seems to have sincerely believed that he had discovered a cure for all illnesses.

It is clear, though, that he had no real insight into why the trances worked. Still, he seems to have understood from the beginning that he needed an explanatory model, and his doctoral dissertation, De Planetarium Influxu (On the Influence of the Planets), which he published in 1766, attempted to provide one. In its 48 pages, he connected hypnotism with a kind of primitive description of cyclical activity in the biosphere, such as heat waves or storms; electricity, magnetism, and even a variant on Newton’s understanding of gravity. He later named the resulting model gravitas animalis, or magnetismus animalis —animal magnetism.

It gave the effects he achieved a certain gloss - electricity, magnetism, and gravity being the high-prestige research areas of the day. We now know that he plagiarized much of this from one of the most prominent and well-regarded English physicians of the previous generation, Richard Meade (1673-1754). He also mixed in some alchemy, proposing that there existed a universal “fluid” in all living forms

that could flow from one organism to another and affect a patient’s health. It wasn’t the first time that observable phenomena were linked to an absurd explanation, and, as time went on, Mesmer became more and more invested in it, even as it caused him to be increasingly shunned by more conventional healers.

When he arrived in Paris, the French medical establishment, alarmed as much by his entrepreneurial success as by his unfounded theories, denied him a license to practice medicine in the city. He got around that by partnering with a disciple, the already licensed Charles d’Eslon. Mesmer was soon at the height of Paris society, collecting followers who included the young French aristocrat and American Revolutionary War hero, the Marquis de Lafayette, as well as no less a patron than the queen, Marie Antoinette. He was lionized by the glamorous, and Mozart made references to him and his magnets in his comic opera Così Fan Tutte. So great was his popularity that his name quickly entered the language, in the form of the verb mesmerize.

By 1784, six years later, Mesmer felt secure enough to propose building a hospital for animal-magnetism treatments, and he quickly raised 340,000 livres, a prodigious sum. This development, his ever-greater fame, his sway over the queen, and the constant lobbying against him by established physicians finally prompted King Louis to establish a commission to investigate his claims.

In March 1784, four doctors were selected, among them Joseph-Ignace Guillotin, for whom the guillotine was named. The four physicians asked the Academy of Sciences to add some scientists to their number, and five were chosen, including Antoine-Laurent Lavoisier, the discoverer of oxygen, and Franklin, known throughout the world as the man who had discovered electricity. The king asked Franklin to head the commission.

Franklin was perhaps the most famous man in the Western world. When Jefferson went to Paris to replace him, he wrote that “more respect and veneration [was] attached to the character of Dr. Franklin than to that of any other person, foreign or native.” He was also a man who lived in considerable pain. He suffered from gout, boils, and decades of hard living, and was mostly confined to his house in Passy, a mile from Paris and seven miles from the king’s seat at Versailles. Why he took the assignment is not clear. He may've felt obligated to the king. He had just talked Louis, the most autocratic and traditional monarch in Europe, into funding a war of liberation fought by the most revolutionary democracy in the world. Perhaps, whatever the condition of his body, his mind and his curiosity were as vigorous as ever.

As was usually the case, Franklin saw deeper into the matter than anyone else, and, at the outset, he wrote what may be the first recorded commentary on hypochondria and psychosomatic medicine. On March 19, before the commission formally began its work, he wrote that

“delusion may . . . in some cases be of use while it lasts. There are in every great, rich city a number of persons who are never in health because they are fond of medicines and always taking them whereby they derange the natural functions and hurt their constitutions. If these people can be persuaded to forbear their drugs in expectation of being cured by only a physician’s finger or an iron rod pointing at them, they may possibly find good effects, though they mistake the cause.”

Franklin was not up to traveling when the commission began its work, so the first meetings were held without him and without his thoughts about how such an evaluation should be undertaken. Since Mesmer himself could not practice medicine, the commissioners went to d’Eslon’s clinic, where they found a handsome, dimly lit room in the center of which stood the wooden tub with its pulverized glass and iron filings. In place of Mesmer’s glass armonica, a piano in the corner provided music. The patients were seated on chairs around the tub, linked together by cords, and each holding the next person’s thumb. Long jointed iron rods projected from the tub; they could be touched to any part of a patient’s body. D’Eslon explained to the commissioners that the tub was the condenser and conductor of the animal magnetism. As they watched, he walked among the patients, touching one or another with a short iron rod and rubbing his hands over their bodies, particularly their lower abdomens.

The treatment went on for hours, and the tension in the room grew. Nervous coughs, hiccups, hysterical cries, sobs, and even convulsions were observed, and d’Eslon explained that they were signs that healing was taking place. Nothing was controlled, and the commissioners left with no sense of what might have taken place medically. After attending a number of such sessions, the commissioners, little more enlightened than when they’d begun, passed on their findings to Franklin.

He saw none of this as very useful. He might have believed in reincarnation and practiced meditation, but he never confused interest with evidence. What was called for, he realized, was some kind of impartial test, and since he could not go to them, he arranged for the other commissioners and d’Eslon to come to him. In late April and early May and at least once in June, they came out from Paris to gather at his residence in Passy.

Among his other accomplishments, Franklin seems to have been the first scientist to consider demographics. On the theory that class and culture might help explain what was happening, and to allow comparisons between populations, the first session at Passy involved only lower-class patients, whose presence Franklin seems to have arranged. They included an asthmatic widow, a woman with a swollen thigh, a tubercular six-year-old boy, a nine-year-old girl who suffered from St. Vitus’ Dance, a man blind in one eye from a tumor, a woman who

had been thrown by a cow and never fully recovered, and a man whose reason for being included is not recorded. After several hours, four of the seven were not affected at all by d’Eslon’s treatments; the remaining three mainly experienced discomfort from having their sore spots pressed. No cures were achieved.

A few days later, the commissioners arranged for four upper-class people to be treated: a Madame de Bory and a Monsieur Romagni, neither of whom had symptoms, or none listed, anyway; a Monsieur Moret, who had a tumor on his knee; and a Madame de V., who had some kind of nervous disorder. To this group were added Franklin, his grandsons, his secretary, an American officer, and a group of patients of d’Eslon.

De Bory and Romagni felt nothing, nor did Franklin, the grandchildren, or the American officer. Madame de V. almost fell asleep, although whether that was from hypnotism or treatment is unclear. D’Eslon’s patients were more responsive, which was not surprising. Franklin then suggested what became the first use of blindness and sham treatments in a scientific test.

The d’Eslon patients were literally blindfolded—which is why the protocol came to be known as “blind”—and the treatments continued. As Franklin had hoped, this was very revealing. The patients could not tell when they were being “magnetized,” and often thought they were when they weren’t, or vice-versa.

During another session at Franklin’s house, they went out into the garden. Mesmer maintained, and d’Eslon agreed, that any living thing could be magnetized, and d’Eslon offered (or, more likely, Franklin asked for) a demonstration. D’Eslon touched an apricot tree in the garden with his wand, supposedly magnetizing it, and said that, afterward, anyone who touched the tree would be affected. Franklin, once again, saw the matter not as a question of belief, but of getting unbiased evidence.

D‘eslon was asked to stand several yards away from the tree. Then, a 12-year-old boy was blindfolded and led out into the garden. He was taken to stand in front of four trees - three controls and the treated one. At the first tree, the boy began to perspire and cough. At the second, he said he felt pain in his head and tiredness in his body. At the third, he said his headache was much worse and volunteered that he felt he was getting close to the magnetized tree. In fact, he was moving away from it. At the fourth tree, he fainted, requiring d’Eslon to revive him.

Franklin and the other members of the commission in attendance were satisfied that the experiments conducted at his house, under the conditions of blindness he had devised, had settled the question of whether animal magnetism was real. It was not.

On August 11, they issued their unanimous report to the king. Benjamin Franklin’s signature

stood first, and such was his preeminence that, throughout Europe and America, scientists and laypeople alike felt that it had been he who had settled the issue. Ever after, history has known this study as the Franklin Commission. Mesmerism was dead, and Mesmer soon left Paris. He was lucky. Ten years later, Lavoisier would lose his head to the guillotine, and Dr. Guillotin just barely missed going under its blade himself. Mesmer ended up in Switzerland, largely forgotten, and years later, he died there in poverty.

Although Mesmerism itself died out, the importance of Franklin’s blind protocol was not lost. In 1799, the English physician John Haygarth took the next step with the development of true placebo treatments. The Franklin protocol had compared treatment and no treatment, under blind conditions. Haygarth refined the idea when he was asked to evaluate a medical device invented by a Connecticut doctor, Elisha Perkins. Like Mesmer’s treatments, Perkins’s were based on the manipulation of a mysterious energy.

Perkins’ apparatus consisted of two rods - one iron, the other brass, about three inches long. The rods were stroked over the body at the site of the affliction. Perkins theorized that they removed a harmful magnetic field. In considering how to go about testing them, Haygarth quite consciously followed Franklin’s lead. He created a second set of rods that looked exactly like the metal ones, but were made of wood, which is of course non-magnetic, and he gave treatments to subjects who were blind to which rods were being used. As Haygarth explained it, what he did was “prepare a pair of false, exactly to resemble the true, tractors.” He added: “Let the secret be kept inviolate. Let the efficiency of both be impartially tried. ”

In another set of experiments, Haygarth coated rods with wax, also making them non-conductors. As the result of using Franklin’s blind protocol and adding his contribution of a deliberately sham treatment, he could report a conclusion much like Franklin’s two decades earlier: “The whole effect undoubtedly depends upon the impression which can be made upon the patient’s Imagination.”

Stuart Green, a surgeon and medical professor on the faculty of the Department of Orthopaedic Surgery at the University of California, Irvine, has traced Franklin’s influence through the history of medicine. He describes what happened next: In a few decades “came numerous placebo-controlled inquiries, in Europe and America, into the professed benefits of [Samuel] Hahnemann’s homeopathic remedies, which cited the Franklin Commission’s strategies. Other blind assessments followed, scrutinizing everything from rheumatic fever and psychologic illnesses to testicular-extract injections and cocaine.”

Franklin began the idea of the blind protocol in science, and Haygarth added the concept of the identical sham treatment. However, the statistical understanding of their day had not evolved enough to supply the final piece necessary for modern medical research, and it would not come for more than a century. It was finally provided by the English mathematician and statistician, Sir Ronald Aylmer Fisher. Beginning

in 1919, Fisher began a several-years effort that would redefine the field of statistics. Franklin and Haygarth had made observations about differences between real and sham or no treatment, but could provide no statistical assessment of the power of their conclusions. Fisher figured out how to do that, augmenting Franklin’s blind protocol with the idea of randomization, calculations of probability, and what he called “likelihood.”

As Dr. Green explains, “The final step in creating a thoroughly modern method of verifying the benefit of a particular treatment followed statistician R. A. Fisher’s insistence that randomly assigning subjects to a treatment group or a control (placebo) group permits valid statistical comparisons between the two groups to some definable level of confidence.”

With that addition, the trail blazed by Franklin and his commission has grown to become the roadway in science that largely determines what medicines we take, what chemicals can be used in our environment, and whether we can trust an experiment’s results.