Natural Science
This passage is adapted from "Magnetic Attraction" by Robert L. Park, Prof. emeritus of Physics, U. of Maryland.
In the early 16th century, the power of lodestone (magnetite) to attract iron filings without touching them suggested great power. Paracelsus, the famous Swiss alchemist and physician, began using powdered lodestone in salves to promote healing. William Gilbert, however, physician to Queen Elizabeth I and father of the scientific study of magnetism, pointed out that the process of grinding the lodestone into powder destroyed the magnetism. Nevertheless, a century later, magnetic cures were introduced into England by Robert Fludd as a remedy for all disease. The patient was placed in the boreal1 position with the head north and the feet south during the treatment.
By far the most famous of the magnetizers was Franz Mesmer (1734-1815), who carried the technique from Vienna to Paris in 1778 and soon became the rage of Parisian society. Dressed in colorful robes, he would seat patients in a circle around a vat of "magnetized water." While Mesmer waved magnetic wands over them, the patients held iron rods protruding from the vat. He would later discover that the cure was just as effective if he left the magnets out and merely waved his hand. He called this "animal magnetism."
Benjamin Franklin, in Paris on a diplomatic assignment, suspected that Mesmer's patients did indeed benefit from the strange ritual because it kept them away from the bloodletting and purges of other Paris physicians. Those physicians bitterly resented Mesmer, an outsider who was attracting their most affluent patients. At the urging of the medical establishment, King Louis XVI appointed a royal commission to investigate his claims. This remarkable group included Franklin, then the world's greatest authority on electricity; Antoine Lavoisier, the founder of modern chemistry; and Joseph Guillotine, the physician whose famous invention would one day be used to sever the head of his friend Lavoisier. The commissioners designed a series of ingenious tests in which some subjects were deceived into thinking they were receiving Mesmer's treatment when they were not, and others received the treatment but were led to believe they had not. The results established beyond any doubt that the effects were due solely to the power of suggestion2. Their report, never surpassed for clarity or reason, destroyed Mesmer's reputation in France, and he returned to Vienna.
Nevertheless, magnetic therapy eventually crossed the Atlantic. Its most famous practitioner in the United States was Daniel Palmer, who in 1890 opened Palmer's School of Magnetic Cure in Davenport, Iowa. Like Mesmer, Palmer soon discovered that his patients recovered just as quickly if he omitted the magnets and merely laid on hands. Thus was founded "chiropractic therapy," and the school became Palmer's College of Chiropractic.3 In recent years, an enormous amount of research has been done on the effect of magnetic fields on the human body, driven not by magnetic therapy, but by safety considerations associated with the phenomenal growth in the use of magnetic resonance imaging (MRI) for medical diagnoses and research. MRI subjects the whole body to a magnetic field about a hundred times stronger than the localized field of even the most powerful therapy magnet. Happily, no ill-effects have been found from exposure to MRI fields. Indeed, there are almost no effects at all—just a few reports of faint sensory responses, such as a slight metallic taste and visual sensations of flashing lights if patients move their eyes too rapidly. The fact is that the stuff we're made of just isn't very magnetic.
That's why scientists were surprised two years ago when Dr. Carlos Vallbona at the Baylor College of Medicine in Houston reported results of a double-blind trial of magnets in the treatment of 50 patients suffering post-polio pain. Some of the patients were treated with commercial therapy magnets4; others were treated with sham magnets. Seventy-six percent of those treated with real magnets reported a decrease in pain, while only 19 percent receiving the placebo felt an improvement. The most frequent claim, which Vallbona supports, is that magnets promote the flow of blood5 to the treated area. It's easy to check. An excess of blood shows up as a flushing or reddening of the skin. That's why the skin turns red when you apply heat; blood is being diverted to the heated area to serve as a coolant6. But you will discover that placing a magnet of any strength against your skin produces no reddening at all. There is no indication that Vallbona tried this.
The argument is that blood, because it contains iron, should be attracted by the magnets. The iron in hemoglobin, however, is not ferromagnetic7. The hemoglobin molecule itself is very weakly paramagnetic, but the fluid that carries the red cells, consisting mostly of water, is diamagnetic—it is weakly repelled. Indeed, small animals have even been levitated in powerful magnetic fields.
As medical scams go, magnet therapy may not seem like a big deal. Magnets generally cost less than a visit to the doctor and they certainly do no harm. But magnet therapy can be dangerous if it leads people to forego needed medical treatment. Worse, it tends to reinforce a sort of upside-down view of how the world works, leaving people vulnerable to predatory quacks if they become seriously ill. It's like trying to find your way around San Francisco with a map of New York. That could be dangerous for someone who is really sick—or really lost.8