In 1904, the Heidelberg chemist Wilhelm Weichardt made a sensational announcement. He promised a utopia in which men would never grow weary, but would be transformed into industrious and tireless machines. Weichardt thought that fatigue was caused by the accumulation of toxins in the blood, and he harvested a concentrated version of this poison from rats that he drove to death by strenuous exercise. As the toxins built up, he observed, the rats descended into a kind of "narcosis" or "stupor," before slowing to a "complete standstill." In his laboratory, Weichardt worked on an antibody. He called the resulting miracle drug—his vaccine against fatigue—antikenotoxin.

In The Human Motor: Energy, Fatigue, and the Origins of Modernity (1990), Anson Rabinbach explains how, after 1870, the religious discourse against acedia or sloth was taken up and replaced by the burgeoning scientific study of fatigue. Fatigue, Rabinbach argues, was considered both a physical and moral disorder: it "replaced the traditional emphasis on idleness as the paramount cause of resistance to work. Its ubiquity was evidence of the body’s stubborn subversion of modernity." In the eighteenth century, idleness had been presented by artists such as Hogarth as the antithesis of industry; in the nineteenth century, fatigue was considered a similar failure—it represented the refusal of the body and mind to keep up with the demands of modern labor. Maurice Keim, one of the first of these nineteenth-century theorists, wrote that "we flee [fatigue] by instinct, it is responsible for our sloth and makes us desire inaction."

Anatomy has been a controversial practice ever since Andreas Vesalius and his colleagues founded the modern anatomical tradition in the mid-sixteenth century. There was a great stigma attached to anatomical dissection and, even worse, the display of human remains. The public regarded such activities as a deliberate desecration of the dead, and this response disputed the central premise of anatomical science. Anatomists claimed to "shine a light on the interior of the body," and dissection became the key method through which physicians and surgeons produced scientific knowledge of the body, as well as the privileged ritual that inducted students into the medical profession. Anatomy was praised as one of the exemplary sciences of the Enlightenment.

The Swedish physician Gustav Zander’s institute in Stockholm, founded in the late nineteenth century and stocked with twenty-seven of his custom-built machines, was the first "gym" in the sense that we know the word today. His mechanical horse was an early version of the Stairmaster, a contraption for cardiovascular fitness designed to imitate a "natural" activity. His stomach-punching apparatus evokes contemporary "ab-crunching" machines. What makes Zander so important, for anyone trying to trace the Cybex family tree, is what happened when his machines, created in a European cultural context, immigrated to the US in the early twentieth century. They are prototypes of the workout equipment now ubiquitous in American life.

In Stockholm, Zander’s institute primarily treated children and male workers. Supported by the state, it was equally accessible to those with and without means. The complex mechanized system was believed uniquely capable of correcting physical impairments brought about both by accidents of birth and by hard labor. A follower of Per Hendrik Ling’s movement cure, Zander argued that the key to health was not blood letting, purging, or strenuous acrobatics (other allopathic "cures" of the time). Instead, one needed to practice "progressive exertion," the controlled, systematic engagement of the body’s muscles in order to build strength.

Not far from our hotel in the center of Palermo is Oratorio di San Lorenzo, a little Baroque church founded by one of those orders that looks after the unwanted dead. The space is crammed with plaster skulls and skeletons, mostly painted, but the last chapel on the right held what we had come to see: matching pairs of stucco corpses by the sculptor Giacomo Serpotta, who could impart life and motion to all kinds of unlikely entities, such as abstract Virtues and tired old scriptural stories. These are called skeletons in the guidebook, but at least half the flesh still clings to the bones, especially on the chest and diaphragm. They’ve also kept their original grime; in the shadows, the stark white flesh is almost black with it.