* * *
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The first person in modern times to take a close scientific interest in stools was Theodor Escherich (1857–1911), a young pediatric researcher in Munich who began microscopically examining babies’ stools in the late nineteenth century. He found nineteen different kinds of microorganisms there, which was considerably more than he expected to find because the only obvious sources of input were their mothers’ milk and the air they breathed. The most abundant of these is called Escherichia coli in his honor. (Escherich himself called it Bacteria coli commune.)
E. coli has become the most studied microbe on the planet. It has spawned literally hundreds of thousands of papers, according to Carl Zimmer, who has written a fascinating book, Microcosm, on this single extraordinary bacillus. Two strains of E. coli have more genetic variability than all the mammals on Earth put together. Poor Theodor Escherich never knew any of this. E. coli wasn’t named for him until 1918, seven years after his death, and the name wasn’t officially accepted until 1958.
Finally, a word or two about flatus, the well-bred term for a fart. Flatus consists primarily of carbon dioxide (up to 50 percent), hydrogen (up to 40 percent), and nitrogen (up to 20 percent), though the exact proportions will vary from person to person and indeed from day to day. About a third of people produce methane, a notorious greenhouse gas, while two-thirds produce none at all. (Or at least none on the occasions on which they have been tested; flatus testing is not the most exacting of disciplines.) The smell of a fart is composed largely of hydrogen sulfide, even though hydrogen sulfide accounts for only about one to three parts per million of what is expelled. Hydrogen sulfide in concentrated form—as in sewage gas—can be highly lethal, but why we are so sensitive to it in trace exposures is a question science has yet to answer. Curiously, we don’t smell it at all when it rises to lethal levels. As Mary Roach put it in her splendid study of all things alimentary, Gulp, “The olfactory nerves become paralyzed.”
All the gases of flatus can make a pretty explosive combination, as was tragically demonstrated in Nancy, France, in 1978 when surgeons stuck an electrically heated wire up the rectum of a sixty-nine-year-old man to cauterize a polyp and caused an explosion that literally tore the patient apart. According to the journal Gastroenterology, this was just one of “many recorded examples of explosion of colonic gas during anal surgery.” Nowadays, most patients undergo laparoscopic, or keyhole, surgery, which involves being insufflated with—pumped full of—carbon dioxide, and that not only reduces discomfort and scarring but eliminates the risk of explosive mishaps.
*1 E. coli is a strange organism in that most strains do us no harm and some are positively beneficial—so long as they don’t end up in the wrong place. E. coli in your colon, for instance, produces vitamin K for you—and most welcome that is. We are talking here about strains of E. coli that hurt you or end up where they shouldn’t be.
*2 St. Martin lived for a time in Cavendish, Vermont, site of the accident that drove an iron bar through the skull of another hapless laborer, Phineas Gage, and also the birthplace of Nettie Stevens, discoverer of the Y chromosome. None of the three were in Cavendish at the same time, however.
16 SLEEP
O sleep, O gentle sleep,
Nature’s soft nurse.
—WILLIAM SHAKESPEARE, HENRY IV, PART 2
I
SLEEPING IS THE most mysterious thing we do. We know that it is vital; we just don’t know exactly why. We can’t say with any certainty what sleep is for, what is the right amount for maximum health and happiness, or why some people fall into it with ease while others struggle perpetually to attain it. We lose a third of our lives to it. I am sixty-six years old as I write this. I have in effect slept through the whole of the twenty-first century.
There isn’t any part of the body that does not benefit from sleep or suffer from its absence. If you are deprived of it for long enough, you will die—though what exactly it is that kills you from lack of sleep is a mystery, too. In 1989, in an experiment unlikely to be repeated on grounds of cruelty, researchers from the University of Chicago kept ten rats awake until they died and discovered that it took between eleven and thirty-two days for exhaustion to fatally overcome them. Postmortems showed the rats had no abnormalities that could explain their deaths. Their bodies just gave up on them.
Sleep has been tied to a great many biological processes—consolidating memories, restoring hormonal balance, emptying the brain of accumulated neurotoxins, resetting the immune system. People with early signs of hypertension who slept for one hour more per night than previously showed a significant improvement in their blood pressure readings. It would seem to be, in short, a kind of nightly tune-up for the body. As Professor Loren Frank of the University of California at San Francisco told the journal Nature in 2013, “The story that everyone tells is that sleep is important for transferring memories to the rest of the brain. But the problem is there’s basically no direct evidence for this idea.” But why we should be required to so utterly give up consciousness for this is a question yet to be answered. It isn’t just that we are disengaged from the outside world when slumbering, but for much of the time are actually paralyzed.
Sleep is clearly about more than just resting. One curious fact is that animals that are hibernating also have periods of sleep. It comes as a surprise to most of us, but hibernation and sleep are not the same thing at all, at least not from a neurological and metabolic perspective. Hibernating is more like being concussed or anesthetized: the subject is unconscious but not actually asleep. So a hibernating animal needs to get a few hours of conventional sleep each day within the larger unconsciousness. A further surprise to most of us is that bears, the most famous of wintry slumberers, don’t actually hibernate. Real hibernation involves profound unconsciousness and a dramatic fall in body temperature—often to around 32 degrees Fahrenheit. By this definition, bears don’t hibernate, because their body temperature stays near normal and they are easily roused. Their winter slumbers are more accurately called a state of torpor.
Whatever sleep gives us, it is more than just a period of recuperative inactivity. Something must make us crave it deeply to leave ourselves so vulnerable to attack by brigands or predators, yet as far as can be told, sleep does nothing for us that couldn’t equally be done while we were awake but resting. We also do not know why we pass much of the night experiencing the surreal and often unsettling hallucinations that we call dreams. Being chased by zombies or finding yourself unaccountably naked at a bus stop doesn’t seem, on the face of it, a terribly restorative way to while away the hours of darkness.
And yet it is universally assumed that sleep must answer some deep elemental need. As the eminent sleep researcher Allan Rechtschaffen observed many years ago, “If sleep does not serve an absolutely vital function, then it is the biggest mistake the evolutionary process has ever made.” Nonetheless, as far as we know, all sleep does is (in the word of another researcher) “make us fit to be awake.”