The remarkable properties of our gastric juices were first revealed, in part, by a young French-Canadian fur-trader name Alexis St. Martin. He was accidentally shot in 1822, and when the wound healed it left an open hole leading directly into the stomach, through which his surgeon was able to dangle bits of cabbage, raw beef and other delicacies, suspended on a silk string.
It’s not clear whether the surgeon, William Beaumont, deliberately kept the fistula open as it healed, but he certainly seized the opportunity. Over the next three decades, he experimented tirelessly, sending samples of St. Martin’s juices to scientists around the world – and even, as Mary Roach recounts in Gulp: Adventures on the Alimentary Canal, sticking his tongue through the hole to check for the taste of acidity.
Be warned: Should this book fall into the wrong hands – an 11-year-old, say, or a particularly juvenile-at-heart journalist – this is the kind of anecdote that will interrupt your dinner-table conversation.
It’s also exactly the sort of obscure and squirmy detail that Roach, the author of previous bestsellers Bonk (on sex) and Stiff (on cadavers), lives for. “Feeding, and even more so its unsavory correlates, are as much taboos as mating and death,” she writes in the introduction to her newest offering. Her mission, then, is to demystify and de-euphemize – to take us on a tour that leads sequentially from mouth to anus, engaging all five senses along the route.
Among the cast of characters we meet: Rodriguez, a convict serving life for murder at Avenal State Prison, who gives Roach the low-down on how, why, and what you can smuggle in your “prison wallet” (rectum, to the rest of us); Gabriel Nirlungayuk, a community health worker tasked with convincing his fellow Inuit to eat more “caribou stomach contents,” partially digested moss and lichen that count as greens in the vegetable-starved north; and George Nichopoulos, Elvis’s doctor, who dishes the brown on the singer’s massively enlarged and perennially stopped colon and its apparent role in his death.
Why do we need to meet these people? Because they exist. Roach’s approach is a refreshing contrast from the endless parade of “big idea” science books that ape Malcolm Gladwell (or, less happily, Jonah Lehrer), in which carefully selected studies and anecdotes gain meaning only insofar as they bolster a catchy and superficially counterintuitive new insight.
And while there’s a certain amount of debunking – of fads like Fletcherizing (chewing each bite of food until it essentially disappears) and colonic irrigation, for example – this isn’t a health book either. You may pick up a few tips about how to avoid Elvis’s fate, but the main thing you’ll have gained by the end of the book is a bunch of knowledge you didn’t have before, and bunch of credibility-straining anecdotes you’re desperate to share with those around you, whether they like it or not.
Of course, there’s a reason Gladwell’s books have launched a thousand imitators: it’s immensely satisfying to follow a train of thought where each new anecdote seems to snap into place to illuminate a bigger picture. Without that big idea, simply stringing together a long series of anecdotes risks settling into cocktail-party novelty mode.
What saves Roach is the vigour with which she pursues each titillating avenue. Could Jonah really have survived in the stomach of a whale? This predictable query spawns two whole chapters that survey an incredible breadth of research, twisting around several surprising corners and culminating in a lab at the University of Nevada, Reno, where at Roach’s prompting a group of researchers feed a live superworm to a frog and use an endoscope with a tiny camera to find out how much, and for how long, the worm struggles inside the frog.
(A related line of enquiry leads us to University of Victoria anthropologist Peter Stahl, who swallowed a segmented shrew without chewing – with the help of “a little bit of spaghetti sauce” – to find out which parts would make it through to the other end unscathed.)
One shortcoming is that Roach never pauses to give us an overview of the whole system – to follow a bite of food from beginning to end, or even to make sure we know our cecums from our colons. You end up absorbing a lot of this in passing by the end of the book, but more exposition might have helped glue the anecdotes together a bit more firmly.
Ultimately, though, Roach has staked a claim on an inherently interesting topic whose powerful taboos are surpassed only by its universality – a point that Alan Kliegerman, the inventor of Beano, makes with great eloquence in one of the three chapters on the origins, odours, and explosive potential of flatulence.
“When I talk to people,” he tells Roach, “when I really get them down to the nitty-gritty, I don’t know anybody, really, in their heart of hearts, who has any objection to the smell of their own.”
Alex Hutchinson writes the Globe and Mail’s Jockology column on fitness science. His latest book is Which Comes First, Cardio or Weights? Fitness Myths, Training Truths, and Other Surprising Discoveries from the Science of Exercise.