By the 1830’s Thomson was claiming three million followers. This was doubtless an exaggeration, but there were parts of the country where a very large percentage of the populace was taking steam baths and lobelia. They included Mississippi, whose governor gave it as his opinion in 1835 that half the people of his state were Thomsonians. In that same year, regular physicians in Ohio were said to have conceded that one out of three Ohioans had deserted to the enemy. And while steam doctors, as Thomsonian practitioners were often called, were most numerous in the South and West, they did a thriving business in some Eastern cities such as Boston, where it was estimated that by the late i Sao’s ten thousand of the town’s sixty thousand inhabitants had been won over by Thomson.

As the metallic gentry took pleasure in pointing out, Thomson’s ideas appealed most strongly to the poor and uneducated. But there were many exceptions. The noted Cincinnati physician Daniel Drake observed sadly in 1829 that the vogue for Thomsonian medicine “was not at present limited to the vulgar. Respectable and intelligent mechaniks, legislative and judicial officers, both state and federal, barristers, ladies, ministers of the gospel, and even some of the medical profession … have become its converts and puffers.”

Thomson’s ideas fitted in beautifully with the spirit of Jacksonian democracy. Self-educated and self-made, Thomson argued that a free people could well dispense not just with doctors, but with lawyers and ministers and all other specially educated and, in his view, parasitic professional castes. It was all right with him if someone who had carefully studied his New Guide to Health should choose to apply its teachings to the cure of disease in others. But he thought it was much better for people to learn how to cure themselves, and toward the end of his life he was deeply troubled because some of his followers, including his own son John, wanted to establish Thomsonian medical schools. Such schools, he feared, would spawn a new elite, and “the benefit of my discoveries will be taken from the people generally, and, like all other crafts, monopolized by a few learned individuals.”

But the egalitarian mood of the United States in the late iSzo’s and :83o’s does not alone explain the remarkable popularity of Thomson’s ideas. Quite apart from the way people had come to feel about bankers and lawyers, Americans had a specific—and justified—grudge against the medical profession. For this was the golden age of heroic medicine, when doctors were taught that it was their duty, at the first signs of illness, to attack it with harsh therapies—therapies that seldom did any good, and that were often far more unpleasant, and sometimes far more dangerous, than the illness itself.

One of the doctor’s most trusted weapons in combating disease was the lancet, which was commonly used in treating even the most trivial disorders. “I remember that a horse kicked me once as Dr. Colby was passing the house,” a survivor of the age of blood-letting wrote years later. “I was not injured much, yet mother called in the doctor, and he at once proceeded to bleed me—I presume on general principles.”

Bleeding did tend to reduce a fever. But it often did so at the price of a throbbing headache and an overwhelming feeling of weakness, and it seems to have had no other beneficial effects. Bleeding was also dangerous. Many doctors believed in letting the blood flow until the patient lost consciousness, and some patients lost their lives as well. Reminiscing in 1878 about medical practice in Ohio in the first quarter of the nineteenth century, a contributor to the Cincinnati Lancet and Clinic recalled “a neighboring physician who proposed to cure and did cure common intermittent [ i.e. , malaria] by blood-letting alone; he bled the patient till he was too weak to shake, and then the disease and the patient went off together.” Physicians in Thomson’s time also tormented patients by raising huge blisters on their bodies, breaking the blisters, and then irritating the resulting sores, a procedure that sometimes led to the development of ulcers and gangrene.

More widespread than either bleeding or blistering, and probably more dangerous as well, was the practice of stuffing sick people with calomel. Unpleasant even when taken in small quantities, in the huge doses favored by many doctors it often had terrible side effects on the patient’s mouth and salivary glands. “It is but the other day,” a Dr. G. C. Howard wrote in the Boston Medical and Surgical Journal in 1835, “that I saw a case of gastroenteritis, in which calomel was pushed till the countenance exhibited a most frightful appearance, owing to the excessive swelling of the cheeks, lips, tongue … and throat, while the saliva flowed in streams.” Many doctors regarded these classic symptoms of mercury poisoning as hopeful signs that the drug was doing its work.