Bully for Brontosaurus (20 page)

The commissioners included several of France’s leading physicians and scientists, but two names stand out: Benjamin Franklin and Antoine Lavoisier. (Franklin served as titular head of the commission, signed the report first, and designed and performed several of the experiments; Lavoisier was the commission’s guiding spirit and probably wrote the final report.) The conjunction may strike some readers as odd, but no two men could have been more appropriate or more available. Franklin lived in Paris, as official representative of our newborn nation, from 1776 to 1785. American intellectuals sometimes underestimate Franklin’s status, assuming perhaps that we revere him
faute de mieux
and for parochial reasons—and that he was really a pipsqueak and amateur among the big boys of Europe. Not at all. Franklin was a universally respected scholar and a great, world-class scientist in an age when nearly all practitioners were technically amateurs. As the world’s leading expert on electricity—a supposed manifestation of Mesmer’s universal fluid—Franklin was an obvious choice for the commission. His interest also extended to smaller details, in particular to Mesmer’s use of the glass harmonica (Franklin’s own invention) as an auxiliary in the precipitation of crises. As for Lavoisier, he ranks as one of the half-dozen greatest scientific geniuses of all time: He wrote with chilling clarity, and he thought with commanding rigor. If the membership contains any odd or ironic conjunction, I would point rather to the inclusion of Dr. Guillotin among the physicians—for Lavoisier would die, ten years later, under the knife that bore the good doctor’s name (see Essay 24).

The experimental method is often oversold or promulgated as the canonical, or even the only, mode of science. As a natural historian, I have often stressed and reported the different approaches used in explaining unique and complex historical events—aspects of the world that cannot be simulated in laboratories or predicted from laws of nature (see my book
Wonderful Life
, 1989). Moreover, the experimental method is fundamentally conservative, not innovative—a set of procedures for evaluating and testing ideas that originate in other ways. Yet, despite these caveats about nonexclusivity and limited range, the experimental method is a tool of unparalleled power in its appropriate (and large) domain.

Lavoisier, Franklin, and colleagues conclusively debunked Mesmer by applying the tools of their experimental craft, tried and true: standardization of complex situations to delineate possible causal factors, repetition of experiments with control and variation, and separation and independent testing of proposed causes. The mesmerists never recovered, and their leader and namesake soon hightailed it out of Paris for good, although he continued to live in adequate luxury, if with reduced fame and prestige, until 1815. Just a year after the commission’s report, Thomas Jefferson, replacing Franklin as American representative in Paris, noted in his journal: “animal magnetism dead, ridiculed.” (Jefferson was overly optimistic, for irrationalism born of hope never dies; still, the report of Franklin and Lavoisier was probably the key incident that turned the tide of opinion—a subtle fluid far more palpable and powerful than animal magnetism—against Mesmer.)

The commissioners began with a basic proposition to guide their testing: “Animal magnetism might well exist without being useful, but it cannot be useful if it doesn’t exist.” Yet, any attempt to affirm the existence of animal magnetism faced an intense and immediate frustration: The mesmerists insisted that their subtle fluid had no tangible or measurable attributes. Imagine the chagrin of a group of eminent physical scientists trying to test the existence of a fluid without physical properties! They wrote, with the barely concealed contempt that makes Lavoisier’s report both a masterpiece of rhetoric and an exemplar of experimental method (the two are not inconsistent because fair and scrupulous procedures do not demand neutrality, but only strict adherence to the rules of the craft):

The commissioners therefore recognized that they would have to test for the existence of animal magnetism through its effects, not its physical properties. This procedure suggested a focus either on cures or on the immediate (and dramatic) crises supposedly provoked by the flow of magnetism during Mesmer’s sessions. The commissioners rejected a test of cures for three obvious and excellent reasons: Cures take too long and time was awasting as the mesmeric craze spread; cures can be caused by many factors, and the supposed effects of magnetism could not be separated from other reasons for recovery; nature, left to her own devices, relieves many ills without any human intervention. (Franklin wryly suspected that an unintended boost to nature lay at the root of Mesmer’s successes. His fluid didn’t exist, and his sessions produced no physical effect. But patients in his care stayed away from conventional physicians and therefore didn’t take the ordinary pills and potions that undoubtedly did more harm than good and impeded natural recovery.) Mesmer, on the other hand, wanted to focus upon cures, and he refused to cooperate with the commission when they would not take his advice. The commission therefore worked in close collaboration with Mesmer’s chief disciple, Charles Deslon, who attended the tests and attempted to magnetize objects and people. (Deslon’s cooperation indicates that the chief mesmerists were not frauds, but misguided believers in their own system. Mesmer tried to dissociate himself from the commission’s findings, arguing that Deslon was a blunderer unable to control the magnetic flux—but all to no avail, and the entire movement suffered from the exposé.)

The commissioners began by trying to magnetize themselves. Once a week, and then for three days in a row (to test a claim that such concentrated time boosted the efficiency of magnetism), they sat for two and a half hours around Deslon’s
baquet
in his Paris curing room, faithfully following all the mesmeric rituals. Nobody felt a thing beyond boredom and discomfort. (I am, somehow, greatly taken by the image of these enormously talented and intensely skeptical men sitting around a
baquet
, presumably under their perukes, joined by a rope, each holding an iron rod, and “making from time to time,” to quote Lavoisier, “the chain of thumbs.” I can picture the scene, as Lavoisier says—Okay boys, ready? One, two, squeeze those thumbs now.)

The commissioners recognized that their own failure scarcely settled the issue, for none was seriously ill (despite Franklin’s gout), and Mesmer’s technique might only work on sick people with magnetic blockages. Moreover, they acknowledged that their own skepticism might be impeding a receptive state of mind. They therefore tested seven “common” people with assorted complaints and then, in a procedure tied to the social assumptions of the
ancien régime
, seven sufferers from the upper classes, reasoning that people of higher status would be less subject, by their refinement and general superiority, to the power of suggestion. The results supported power of suggestion as the cause of crises, rather than physical effects of a fluid. Only five of fourteen subjects noted any results, and only three—all from the lower classes—experienced anything severe enough to label as a crisis. “Those who belong to a more elevated class, endowed with more light, and more capable of recognizing their sensations, experienced nothing.” Interestingly, two commoners who felt nothing—a child and a young retarded woman—might be judged less subject to the power of suggestion, but not less able to experience the flow of a fluid, if it existed.

These preliminaries brought the commissioners to the crux of their experiments. They had proceeded by progressive elimination and concentration on a key remaining issue. They had hoped to test for physical evidence of the fluid itself, but could not and chose instead to concentrate on its supposed effects. They had decided that immediate reactions rather than long-term cures must form the focus of experiments. They had tried the standard techniques on themselves, without result. They had given mesmerists the benefit of all doubt by using the same methods on people with illnesses and inclined to accept the mesmeric system—still without positive results. The investigation now came down to a single question, admirably suited for experimental resolution: The undoubted crises that mesmerists could induce might be caused by one of two factors (or perhaps both)—the psychological power of suggestion or the physical action of a fluid.

The experimental method demands that the two possible causes be separated in controlled situations. People must be subjected to the power of suggestion but not magnetized, and then magnetized but not subject to suggestion. These separations demanded a bit of honorable duplicity from the commissioners—for they needed to tell people that nonmagnetized objects were really full of mesmeric fluid (suggestion without physical cause), and then magnetize people without letting them know (physical cause without suggestion).

In a clever series of experiments, designed mainly by Lavoisier and carried out at Franklin’s home in Passy, the commissioners made the necessary separations and achieved a result as clear as any in the history of debunking: Crises are caused by suggestion; not a shred of evidence exists for any fluid, and animal magnetism, as a physical force, must be firmly rejected.

For the separation of suggestion from magnetism, Franklin asked Deslon to magnetize one of five trees in his garden. A young man, certified by Deslon as particularly sensitive to magnetism, was led to embrace each tree in turn, but not told about the smoking gun. He reported increasing strength of magnetization in each successive tree and finally fell unconscious in a classic mesmeric crisis before the fourth tree. Only the fifth, however, had been magnetized by Deslon! Mesmerists rejected the result, arguing that all trees have some natural magnetization anyway, and that Deslon’s presence in the garden might have enhanced the effect. But Lavoisier replied scornfully:

Nevertheless, the commissioners persisted with several other experiments, all leading to the same conclusion—that suggestion without magnetism could easily produce full-scale mesmeric crises. They blindfolded a woman and told her that Deslon was in the room, filling her with magnetism. He was nowhere near, but the woman had a classic crisis. They then tested the patient without a blindfold, telling her that Deslon was in the next room directing the fluid at her. He was not, but she had a crisis. In both cases, the woman was not magnetized or even touched, but her crises were intense.

Lavoisier conducted another experiment at his home in the Arsenal (where he worked as Commissioner of Gunpowder, having helped America’s revolution with materiel, as much as Lafayette had aided with men). Several porcelain cups were filled with water, one supposedly strongly magnetized. A particularly sensitive woman who, in anticipation, had already experienced a crisis in Lavoisier’s antechamber, received each cup in turn. She began to quiver after touching the second cup and fell into a full crisis upon receiving the fourth. When she recovered and asked for a cup of water, the foxy Lavoisier finally passed her the magnetized liquid. This time, she not only held, but actually imbibed, although “she drank tranquilly and said that she felt relieved.”

The commissioners then proceeded to the reverse test of magnetizing without unleashing the power of suggestion. They removed the door between two rooms at Franklin’s home and replaced it with a paper partition (offering no bar at all, according to Deslon, to the flow of mesmeric fluid). They induced a young seamstress, a woman with particularly acute sensitivity to magnetism, to sit next to the partition. From the other side, but unknown to the seamstress, an adept magnetizer tried for half an hour to fill her with fluid and induce a crisis, but “during all this time, Miss B…made gay conversation; asked about her health, she freely answered that she felt very well.” Yet, when the magnetizer entered the room, and his presence became known (while acting from an equal or greater distance), the seamstress began to convulse after three minutes and fell into a full crisis in twelve minutes.

The evident finding, after so many conclusive experiments—that no evidence exists for Mesmer’s fluid and that all noted effects may be attributed to the power of imagination—seems almost anticlimactic, and the commissioners offered their result with clarity and brevity: “The practice of magnetization is the art of increasing the imagination by degrees.” Lavoisier then ended the report with a brilliant analysis of the reasons for such frequent vogues of irrationalism throughout human history. He cited two major causes, or predisposing factors of the human mind and heart. First, our brains just don’t seem to be well equipped for reasoning by probability. Fads find their most fertile ground in subjects, like the curing of disease, that require a separation of many potential causes and an assessment of probability in judging the value of a result: