What then, was the class-conscious white-collar urban dweller supposed to do to stay on top of his game? Why, expand his energy of course! Building “muscle could both expand energy production and increase the efficiency of energy consumption” [p. 30]. Unfortunately, this energy was not infinitely expandable. In thermodynamics, the law of entropy states that energy is never created but is rather constantly diminishing; so experts reconciled this old physics to the new beliefs by creating the concept of usable energy. Usable energy—or the energy available for use by the body—had to be increased in order to meet the ever-increasing demands of modern life.

What is astonishing is that this hypothesis has been recycled several times and is enjoying a new wave of popularity today. Back in the 1970s, when the latest fitness culture emerged, the focus was on cardio-vascular health achieved through aerobic sports. Running, jogging, and aerobic dance were the keys to physical and mental fitness. Presently, though, fitness experts claim that “resistance training” (muscle building) must be added to achieve true fitness. Lean muscle mass, apparently, burns more calories and hence produces more energy even at rest, creating a true 24-hour factory line. The means of building muscle haven’t changed much since the nineteenth century either. Fitness machines today are based on the same principles as fitness machines in the 1860s. Even Pilates, the “new” resistance training without machines, was invented nearly a century ago [p. 213].

As machine technology became more common in everyday life, it became possible for people to believe that their bodies could be improved by the same technological principles. It wasn’t too far of a jump, then, to believing that electric technology could also improve the health and fitness of the body was the next logical step. However, there were differences in the concepts surrounding machine and electric technology:

Further, the process of transferring energy was less laborious and time-consuming than using machines. Again, this “get-fit-quick” idea has incredible staying power. Anyone who watches late-night TV has seen ads for electric devices which build muscle and reduce unsightly flab just by placing the adhesive discs to the abdomen and turning on the machine. Such devices usually don’t claim to transfer energy directly; the consumer has to make the connection that increased energy is a consequence of having a flatter stomach and being more sexually desirable. That would be great, if it worked. Then—as now—advertising helped to sell devices to a public looking for a quick and easy solution to their physical problems and emotional insecurities.

Once electricity had been established as a means to better health and fitness through energy transferal, radium was easier to accept.

Between 1896 and 1900, radium technology—X-rays—was used for a variety of medical procedures, such as bone repair and bullet removal (alas, bullet removal was and is extremely important in American society). However, X-rays also captured the popular imagination:

If only! Radium, also known as “liquid sunshine,” died out as its foremost promoter, William Hammer, died a slow and painful death due to its use. Like machine and electric fitness technology, radium has its modern equivalent, athletic steroids. They certainly work, but their side effects—shrinking testicles, hair loss, impotence, “roid rage” and sometimes death—probably aren’t worth it.

A lesser author and researcher would be tempted to use an ironic or judgmental tone when describing how mechanical, electrical and chemical principles were applied to the human body in search of increased energy, sexual vigor and endless youth. De la Peña successfully avoids applying twenty-first-century thinking and morality onto nineteenth-century scientists, promoters, and consumers. It is the reader who is likely to be amused or shocked, especially when studying the illustrations.

These are truly well chosen and shed light on what otherwise might be dry material. Figures 10 and 11 [pp. 76-77] show that modern gym equipment hasn’t changed all that much over the years. They are still based on a system of weights and pulleys in different configurations. The other interesting thing about these illustrations, however, is that the subjects in the pictures—though exercising—are in full Victorian costume. Some illustrations are a little disturbing, such as Figure 15 [p. 104] showing a man holding an electric wire while his feet are in a pan of water! Figure 26 [p. 155], though, is deeply upsetting: “Killing the Nineteenth Century with Edison’s Magno-Electric Vitalizer” depicts a sort of übermensch standing with his foot on the head of a dead Native American.

The most provocative illustrations are in Chapter 4, “Powering the Intimate Body.” Figure 22, “Pulvermacher’s Belt and Suspensory Appliance” [p. 139] shows a device which delivered galvanic current to the testicles. Figure 28, the “Thermalaid” [p. 164] shows an electric vibrator-like device which stimulated the prostrate from the inside. These appliances also have their modern-day counterparts which can be found in any “adult” shop. If you want to know more about them, well, you’ll just have to read the book.

To conclude, I would recommend this book to readers who like “historical non-fiction,” lay readers who have an interest in science and technology, and readers who want to read something while on the treadmill or stationary bike at the gym.