EARLY ONE MORNING in the winter of 1890, a young British factory worker leaned from his bed to check the time. It was not yet dawn, the streets of Manchester still dark and shuttered. As he struck a match to see the hands of his timepiece, he happened to emit a belch. “To his consternation,” wrote Dr. James McNaught in the British Medical Journal, “the gas took fire, burned his face and lips considerably, and set fire to his moustache.”
Cases of “inflammable eructation”—McNaught cites eight other cases—are perplexing. The gas in a typical belch is either carbon dioxide (from carbonated drinks) or air swallowed while eating or drinking, both nonflammable. The healthy human stomach, unlike the colon, does not produce hydrogen or methane. Gastric acid’s job is to kill microorganisms; without them there can be no hydrogen-or methane-producing fermentation. Even if a relative few bacteria survive in a stomach—and some species can, we now know—the chymified food is passed on to the small intestine too quickly for fermentation to make much headway.
McNaught reached for his stomach tube. It had been five hours since the factory worker ate, a time lag normally sufficient for the stomach to finish its duties and pass the chyme along to the small intestine. Yet up came a pint and a half of a sour-smelling, soupy matter with a sediment of “grumous* remains of food.” And gas, lots of it, visible as a head of frothy bubbles, foaming and bursting like the contents of a mad scientist’s beaker.
To identify the gas and confirm its flammability, McNaught had only to collect some from the headspace of the beaker and set it alight. But that’s no fun. Instead, on a different day, McNaught had the man yet again visit his office. Through a tube, he poured water into the misbehaving stomach, to displace the gas. As he did so, he held a flame to the invisible plume issuing from the man’s mouth. “The result . . . was to produce a flame of dimensions alarming to both the patient and myself.” Maybe I’m projecting, but a poorly suppressed schoolboy glee occasionally surfaces in McNaught’s writing, setting it off from the typical Hippocratic benevolence of British Medical Journal prose. If I had a medical license, I fear I’d be a Dr. McNaught.
It turned out that owing to strictures of the pylorus, the stomach’s lower sphincter,* the food in the young man’s stomach was held back an uncommonly long time. Plus, McNaught claimed to have cultivated strains of acid-resistant, gas-producing bacteria. Carbohydrates plus bacteria plus time and body heat equals fermentation.
The story made me curious about cows. As we learned earlier, the rumen is a vast fermentation pit, a massive bacterial slum. A grazing cow can produce a hundred gallons of methane a day, vented, as stomach gases typically are, through the mouth. You would think that cow-belch-lighting would rival cow-tipping as a late-night diversion for bored rural youth. How is it that growing up in New Hampshire I never heard a cow belch? My ag pal Ed DePeters had the answer. When a ruminant is feeling bloated and needs to make room in her rumen, she pushes out some methane, but instead of belching it up, she can shift her internal tubing to reroute the gas down into the lungs and then quietly exhale it. To, say, a pronghorn out on the savannah, quiet can be key to survival. “Ungulates in the wild tend to go off and hide someplace while they ruminate,” DePeters explained. “If a lion walks by and hears a loud urrp . . .” Sayonara, antelope.
Because my readers, perhaps more than anyone else’s, might be inspired to head out to the pasture with a lighter in their pocket and bovine malfeasance in their heart, let me add this: lighting a cow’s breath will not produce a McNaughtian geyser of flame. Because of the afore-described methane rerouting system, the gas is diluted by nonflammable gases in the breath. For ignition, you would need the sort of concentrated blast that is a belch. And cows don’t belch.