Ever since the Columbia University anatomy professor Michael Gershon launched the field of neurogastroenterology, in 1999, by pointing out that the human gastrointestinal tract is home to some hundred million neurons, scientists have been amassing evidence of the so-called gut-brain connection, the hardwired link between emotion and digestion. An entire spectrum of feelings, from fullness to anxiety, has been shown to originate in the stomach before bubbling up into consciousness. Until earlier this year, though, it wasn’t clear precisely how gut sensations become brain-bound nerve impulses. Then, in a paper in the Journal of Clinical Investigation, Diego Bohórquez and his colleagues at Duke University documented the existence of previously unknown gut-brain circuitry. Bohórquez’s group observed that specialized receptor cells scattered along the intestines of mice were equipped with tail-like structures that allowed them to pass information directly to gut neurons and straight into the nervous system. When Bohórquez isolated one of these cells, called a neuropod, and put it in a petri dish with a neuron, it reached out over the cellular equivalent of half a football field to link up. Coincidentally, the same day that the Bohórquez paper was published, the U.S. Food and Drug Administration approved the Maestro System, an implantable anti-obesity device that delivers electrical pulses to the vagus nerve, the highway along which any information that neuropods share with gut neurons has to travel in order to reach the brain. In the past, doctors who severed the vagus nerve—a standard treatment for peptic ulcers—noticed that their patients lost weight, as hunger signals from the gut hit a roadblock.

Though our understanding of the mechanics of the gut-brain connection is new, our fascination with it is most definitely not. The Victorians, in particular, were “obsessed” by the stomach and its discontents, as the historian Ian Miller notes in his book “A Modern History of the Stomach.” The result was an outpouring of popular and medical literature, which advocated a surprisingly modern sense of gastric happiness as the key to both physical and mental well-being. Miller argues that this fixation was a response not only to contemporary medical thought but also to the seismic shift in diet that was taking place in the United Kingdom at the time—the first steps toward today’s industrialized food system. Cities were growing larger, farmers were embracing mechanized agriculture, and new ingredients were flowing in from across the empire. Without the natural limits of seasonality and geography, the British stomach was under assault by refined, exotic, and adulterated foods, in combinations and quantities that it was not equipped to handle. Seemingly the only solution, Miller writes, “was to educate the public on how best to navigate modern conditions by paying close attention to food intake and digestion.”

Sam Bompas came across a peculiar symptom of this Victorian gut craze in 2012, in an antiquarian bookstore. Bompas, the co-founder of Bompas & Parr, a London outfit that specializes in “flavor-based experience design”—funeral jellies, orange-scented fireworks, an upside-down banquet—had picked up a copy of Sydney Whiting’s “Memoirs of a Stomach; Written by Himself, That All Who Eat May Read,” from 1853. It was a classic example of an “it-narrative,” a popular subgenre of Georgian and Victorian fiction in which a nonhuman narrator—a banknote, a corkscrew, an embroidered waistcoat, a digestive organ—is endowed with consciousness so that it may tell a story.

The book begins with a modest self-introduction from its narrator: “My personal appearance, I must acknowledge, is not prepossessing, as I resemble a Scotch bagpipe in form.” Then, beginning to feel his oats, Mr. Stomach ventures that, “as far as intellectual faculties are concerned, I consider I hold a superior position to my helpmate Mr. Brain.” Though his tone may be light, he has a serious message to deliver: mistreat me at your peril. “My health influences directly and indirectly a man’s actions, and his mode and tone of thought,” he writes. Having expressed his low opinion of smoking, binge drinking, gluttony, late breakfasts, and oysters, Mr. Stomach ends his hundred-and-twenty-page account with a handful of rules “to keep, through my assistance, the entire corporeal system in health and comfort.” Chief among these is “CARE in the selection of DIET,” though moderation in consumption, regularity of meals, exercise, and adequate mastication are also “necessary observances,” and the reader is enjoined to “never dine alone.”

Image courtesy Bompas & Parr

In the course of his research into the science of sensory perception, Bompas had become increasingly aware of the importance of the gastrointestinal system. “Humans actually have more brain cells in their guts than a cat has in its head,” he told me. He and his business partner, Harry Parr, decided that a modern reissue of “Memoirs of Stomach” was in order. This raised the question of how the book should be illustrated. The pair were accustomed to images of impeccably styled meals, but since the text provided a gut’s-eye view, they decided that the photographs should, too. Bompas spent six months acquiring a pill camera, a capsule about the size of a large multivitamin that was developed as an alternative to endoscopy. “Then we thought, having gone through all this rigmarole, it might be quite interesting to do it at a public event,” he said. The result, as he puts it in the introduction to the Bompas & Parr reissue of “Memoirs of a Stomach,” was like a trip through “fleshy hyperspace.”

Bompas recruited Gizzi Erskine, a British TV chef, to swallow the pill camera onstage at King’s College London. (Nigella Lawson was his other choice, but Erskine’s agent responded first.) There, on a large projector screen, some three hundred ticket holders watched the pill’s journey from Erskine’s mouth through her cardioesophageal sphincter and into her stomach, where it was joined by whole gummy bears and bites of pizza and jostled around by intermittent dancing. For Bompas, the beginning of the journey was particularly unsettling: “The texture of the tongue is quite unattractive,” he told me. Erskine had agreed to the stunt on the condition that no filming took place “at the other end,” so only the first ninety minutes of a twenty-four-hour odyssey were documented. A jazz band improvised musical accompaniment, a pill-cam technician with more than two thousand “passes” under his belt narrated, and a prominent U.K. gastroenterologist provided context, including a list of the things that he has retrieved from British stomachs, car keys and hairballs being the most common.

The resulting images, as Bompas admits, are “pretty gruesome”—droplets of oil and saliva and shreds of yellow cheese bouncing around Erskine’s pink, brain-coral-like interior. They became “A Journey to the Centre of the Gut,” the modern-day response to “Memoirs of a Stomach.” In the Bompas & Parr edition, the two are interleaved, the color photographs of Erskine’s innards side by side with a facsimile of the third edition of Whiting’s book. This presentation makes clear that the Victorian interest in digestion was accompanied by quite an accurate intuition regarding its mechanics. Twenty-first-century pill-cam technology allows us to see food from Mr. Stomach’s perspective, verifying his lurid descriptions. Meanwhile, scientists are proving the truth of his boast of “a double set of electric wires” connecting him to Mr. Brain, “by which means I could, with the greatest ease and rapidity, tell him all the occurrences of the day as they arrived, and he also could impart to me his own feelings and impressions.”