Gathering Our Selves

Though none of us begins that way, within the first few months every normal healthy human being is (by cell number) more than 90 percent bacteria. How can that be?

LUDWIG VAN BEETHOVEN

February 1824, Vienna

It is snowing, perhaps, and cold, surely. The streets are nearly empty. The sparkling flakes that fill the stone crevices are radiant with candle and gaslight. In a small villa near the city's center, at Beatrixgasse-Ungargasse 5, a white-haired man in his fifties has just penned the final notes of what will someday be called the greatest piece of music ever composed. Beyond his windows, all of this goes unnoticed by the glittering crystals and the few men and women still moving through the snowy streets. But the moment will be remembered forever by millions of other men and women still unborn. The light dims, and the man turns toward his bed.

Ludwig van Beethoven has just completed his final symphony, and it is a masterpiece. Such a masterpiece that, even today, every one of us immediately recognizes the grand finale of the Ninth Symphony. Because of the splendor of that music, most of us would agree that Beethoven was a genius. But where did that apparent genius come from? In truth, Ludwig had help—especially that night.

HENRY PERRY

June 1913, Paris

To the best of my recollection, I have known only one truly crazy person Known well, that is. I, like most of us, have had more than one opportunity to observe the actions of the truly crazy from a distance—Dick Cheney, for example. But Dick and I were never on speaking terms, never even friends on Facebook. My mother, of course, eventually achieved craziness; perhaps my father did, too. But they don't really count, because at one time or another all of us consider our parents to be insane.

Henry Perry was one of my mother's older brothers. He was born in Kansas in the 1890s—third or fourth in a family that would someday total thirteen. Unlike some, Henry wasn't born crazy. It was a thing he acquired along the way. Nor did Henry achieve craziness on his own. Like Beethoven, Henry had help. Henry came by that help one night in Paris.

About 100 years after Beethoven conspired with others to write his Ninth symphony, Henry Perry sits smoking a cigarette at a small table in a rundown bistro in Paris. Across the table from him is a surprisingly beautiful woman. Henry has seen nothing but trench foot and mustard gas for the last months and is completely taken with the scent and the looks of the woman across from him. The woman, of course, is a whore. That makes no difference to Henry. Her breasts are magnificent, her breath cinnamon and cloves. I've earned this, he thinks. A simple wish for a single night of pleasure.

Henry is young, blond haired, and tall. The weeks at war have thinned him, and now he is shaped more like a man than a boy. His uniform, by some monumental accident, fits him perfectly. Tonight, Henry's long arms and legs seem just right to him and his escort. And Henry is sane.

Perhaps the waiter offers more wine. Perhaps they accept. The evening lengthens into darkness. Henry's desire gathers heat. Surprisingly, especially to her, the woman's interest is piqued as well. They move closer to one another. But that's what people do here, sit in dim corners beneath dark wood and eat from one another's spoons, like lovers.

Neither of them expects any of this to last beyond that night. That is what they have planned. That is what they have agreed upon. But there are others here this night, making plans of their own.

THE WRATH OF GOD

By the time I met Henry, he was completely insane. He couldn't speak in complete sentences. He couldn't walk the fifty feet across our backyard without jerks and staggers. Sometimes he drooled.

Henry was living, then, at the VA hospital in Salt Lake City, Utah. Every Sunday afternoon, my father would gather him up in our family's Ford station wagon and bring him out to our house in Bountiful for dinner. Henry seemed to like that.

His eyes were still piercingly blue, his hair still blond, though mottled with gray, and he still had the whippet-thin frame of a soldier. But the rest was no longer Henry.

In spite of his peculiarities, or maybe because of them, I enjoyed my uncle. He cursed and spat and wore soiled clothes, all of which I admired. But clearly something was different about Henry. Henry wasn't working alone either.

The voices that rattled in Beethoven's deaf ears that night in Vienna were not human voices. Mercury, from the vapor baths for his lifelong syphilis, silvered nearly every tissue in his body. Lead from his water or his knives and spoons was inside his neurons redirecting traffic. But, most important, the syphilis bacterium itself was in his brain and his spine playing its own music. Continual, bone-splintering pain worked at every nerve ending as Beethoven sat down that evening. Before the Ninth Symphony was finished, each of these others had its say. The Ninth was a cooperative effort.

A part of that same music was playing inside of Henry's head the day I met him in Bountiful, Utah. A tune with a ragged edge. In its own way, Henry's craziness was nearly as perfect as Beethoven's Ninth Symphony. I don't know if my uncle had ever heard of Beethoven, but a thing that had once been Ludwig's was now Henry's.

THE INFECTIONS THAT MAKE US HUMAN

Inside each of us a symphony is playing itself out. Syphilis is only one player in one of those symphonies. But because of the shrill note this bacterium plays, it gets a lot of attention. And because of that, the word infection carries its baggage like a handful of maggots. It shouldn't. Infections make us who we are and connect us to one another in the most intimate of ways.

Besides the bacteria that haunt us, there are others—gathered from seat cushions and kisses, from forks and knives and cheese rinds, and from mothers' wombs and breasts. Beyond the howling of T. pallidum, the syphilitic spirochete, others play a more subtle tune, and these others we couldn't live without. We have sought them out in the some of the lowest places imaginable, but they sustain us.

Bacteria rule the world of living things. All by themselves, bacteria account for well over 99 percent of all organisms—just as they have for all of time. Bacteria numbers are truly staggering—10 ²⁹ on, in, and above the Earth; 10¹⁴ per person. If we round up the number of human beings on this planet to 10¹⁰, bacteria outnumber us by a factor of 10¹⁹—a lot. Inside our own skin, we carry around about 10¹³ human cells. Even within the space we call us, bacteria outnumber our cells by a factor of 10. Each of us, by cell number, is roughly 90 percent bacteria.

Clearly, we don't begin life that way. No bacteria shared our mothers' wombs. But by the time we are just a few months old we are lousy with bacteria. How does this happen? How does each one of us come to be so massively infested with these microscopic vermin?

PROMISCUITY

More than once I asked my mother to explain Henry's peculiarities, but it wasn't until long after his death that she told me the truth. Henry had syphilis. For my mother, that was a like slap in the face. Syphilis was a disease of the poor, the deviant, the unwashed. It was a sickness that fell upon the godless as punishment for their sins.

Syphilis, of course, isn't punishment for anything. It is simply a bacterium—Treponema pallidum—trying to make a living. T. pallidum moves from person to person during the most intimate of human acts. Wounds, torn tissues, cracked skin are all open doors for syphilis.

One night in Paris was all it took for Henry. Well, not all. It also took a partner and more. That night, as Henry ogled the young woman, someone invisible to everyone else was in the bistro. A creature who knew full well that this was not to be a one-night stand. The next morning, as Adrienne stayed behind in her small flat overlooking the rue Michelet, the spirochete, almost magically, both stayed with Adrienne and left with Henry.

Fleming's penicillin wouldn't come along for decades, so over the years, T. pallidum had its way with Henry. First, there was a minor wound, a chancre, not at all painful. And then it went away. Henry was relieved. Later, a rash spread across Henry's palms and the soles of his feet. He assumed it was left over from the trenches of France.

Headaches followed Then the spirochete took Henry's joints—his knuckles, his knees—then it took his eyes, his spine, and his mind. When there was nothing more to take, T. pallidum took my uncle Henry's life, just as it had Beethoven's. It is even possible that Henry's syphilis could be traced in a direct line to Beethoven's syphilis, as clearly as any genetic link. After all, syphilis infects only human beings. Because of that, every syphilitic person is tied irrevocably to a long line of other syphilitics—reaching centuries beyond Beethoven and Vienna. To some that may sound horrible. But in fact the same can be said for millions of other infections thriving inside every living person. Our infections link us to one another as tightly as our humanity. Undoubtedly, Henry's lover paid just as dearly for her indiscretion, as did some of her previous lovers and so on back to Beethoven and beyond.

Usually, we only really notice that—how our infections link us to one another—when the infections maim and kill us. But it happens all of the time. A touch, a breath, a spoon, a handrail, a kiss, and bits of us move from one to another. A shared bottle of spring water or a meal and we are no longer who we just were. Abruptly, I am you and you are me and we are all together. And it all begins before we are even fully born.

BETRAYED AT BIRTH

At the dark moment of fertilization—when, with a final flash of its pearly tail, a sperm penetrates an egg—we are more human than we will ever be again. Sperm, egg, zygote, blastula, embryo—human. And for the next nine months, nestled in the sterile seas of our mothers' amniotic fluid, we remain mostly human.

But as birth nears, things change. In anticipation of our arrival, our soon-to be mothers begin preparing a special nursery. Inside these women's birth canals, bacteria sprout like weeds. Lactobacilli, the same bacteria found in yogurt and buttermilk, divide and spread throughout the passage that we must traverse as we enter this world. About 1/100 the thickness of a human hair and as long as 1/25 the thickness of this page, these bacteria rise like fingers to prod us into reality.

On our way into this world these bacteria immediately infect us. Before our mothers have shared so much as a single caress, they have inoculated every one of us, infected us with billions upon billions of squirming, wriggling, living bacteria.

And it appears they must. If lactobacilli don't flourish inside a mother's vagina, premature delivery happens more often than in infected mothers. And infants born prematurely or by cesarean section face many challenges that full-term and fully infected infants don't. So everything conspires to ensure our immediate infestation.

After birth, things get dramatically dirtier. Our first breaths, the arms of the doctor or midwife or forest floor—all are teeming with microbes. Even in the relative sterility of a hospital delivery room, we roll in the powdered sugar of this world like a warm doughnut fresh from the oil. And as we do, we are quickly covered with layer upon layer of bacteria and fungi and viruses and even a few parasites. Life as a separate entity is over. From this moment on, no one of us ever walks alone.

As a mother nurses her child, she lays the groundwork for further infection. The milk she feeds her child is laced with proteins. Some of these proteins are fertilizers for more infectious microbes, especially Bifidobacteria.

The proteins in mothers' milk enrich the soil of the newborns' intestines. In that soil, Bifidobacteria push aside a few of the Lactobacilli and attach to the baby's intestines. Together these two bacteria weave a blanket inside the child, a protective blanket.

Children with too few bacteria often develop a disease called oral thrush— a yeast infection of the mouth. Without protective bacteria, a child's mouth sprouts thick white crusts of yeast across cheeks and gums and lips. As it spreads, the yeast digests the human tissues beneath and causes painful destructive ulcers. Without bacteria, life is harder.

The process of our infection appears completely chaotic, but it isn't.

Lactobacilli and Bifidobacteria come first. Then, as the mother withdraws her milk, the Bifidobacteria give way to other strains of bacteria, and much later, as the hormones of puberty flood the body, still other bacteria arrive and thrive. Layer upon layer is laid down. Ordered and structured by time and chemistry, we absorb our surroundings. Literally, we become what we eat or drink or touch or breathe. We are what we wear. We become those who caress us and those whom we caress in return.

From the world that surrounds us, we gather ourselves. Once pure and sterile, filled only with human cells, we transform into a microbiological metropolis covered with living things whose names read like a Linnaean litany—Staphylococcus aureus and epidermidis; Streptococcus mitis, mutans, viridans, pyogenes, and pneunominiae; Trichomonas tenax; Candida albicans; Hemophilus influenzae.

Our skin sprouts a cornucopia of microorganisms, including nearly 200 different strains of bacteria and several species of fungi—within human skin as well as upon it. And bacteria are not distributed uniformly across human skin. Some bacteria prefer the navel, others the forearm or underarm, and so on. And if you move bacteria from the forearm to the belly button, they don't last. In a short while, the original geographic pastiche reestablishes itself. Human skin is a mosaic of bacteria, each piece with a deep sense of place and purpose.

Human eyes gloss over with three or four strains of bacteria. Noses, throats the upper reaches of our respiratory systems blossom with more than six different types of bacteria. Mouths cultivate a half dozen species of bacteria and fungi. Lower urethras fill with more than ten different bacteria, a few fungi, and parasite or two. But by far, the greatest numbers of bacteria settle and prosper our intestines. In places, the bacterial coat in our large intestine is an inch thick. And our feces, by dry weight, are 50 to 60 percent pure bacteria.

While no one notices, and with little or no effort on our part, we become menagerie, a walking ecosystem, a universe apart—10 percent human, 90 percent other (maybe).

And it isn't just the number of microbes that is staggering. When scientists sequenced the human genome, they found only about 30,000 different human genes strung out along forty-six human chromosomes. But the bacterial genes we gather far outnumber the genes inside every human cell given to us by our mothers' eggs and our fathers' sperm. Amazingly, nearly 99 percent of the genes inside human beings aren't human. Perhaps even more amazing, inside each of us the mixtures of bacteria are as individual as human fingerprints.

INFECTION AND INDIVIDUALITY

Surprisingly, the community of bacteria within or upon one man or one woman is not simply an accidental consequence of birth and geography.

Where we are born is unquestionably important. Infants born in developing countries acquire bacteria that differ considerably from those of infants born in developed parts of the world. Children born in different hospitals may have very different strains of bacteria in their intestines. And breast-fed babies' intestines contain mostly Bifidobacteria, while formula-fed babies' intestines have more potentially dangerous bacteria, such as coliforms, enterococci, and Bacteroides. Where we are born and what we eat do make a difference. But our surroundings and our food are not the only factors.

No two of us are more alike than identical (monozygotic) twins. These children have the same chromosomes and the same human genes. Usually, identical twins also live in the same home, eat the same food, breathe the same air, and drink the same water. But there is one way they differ dramatically—each twin has his or her own, individually tailored set of bacteria.

Beyond monozygotic twins, even within a single geographic area, the species of bacteria found inside people vary dramatically from person to person. This is equally true of married people and families living in the same environment. You and your spouse, partner, brother, or sister house significantly different collections of bacteria.

She might have a little more Staphylococcus aureus in her nose or vagina than you have. Candida albicans might find him a little more attractive than you. Helicobacter pylori (part of the cause of peptic ulcers) makes a living for itself in some stomachs and small intestines but not others. Citrobacter(which can cause diarrhea and perhaps meningitis) is comfortable with some of us but not Others. Our collections of bacteria are more individual than our fingerprints.

Many Japanese people even have special bacteria that millennia ago stole genes from oceanic bacteria. These bacteria help to digest seaweed—a major component of sushi and other Japanese cuisines.

Bacteria, from the creepy, crawly, and slimy spaces in this world, may be just as important for making human individuals as brains or genes. Who I am depends on who they are, and vice versa.

THE BACTERIA THAT STICK

We acquire our normal floras (our individual collections of bacteria) with no effort whatsoever. We eat, we breathe, we poke our fingers into the soft parts of this world. In the process, we gather billions upon billions of bacteria—as easily as a ship's hull gathers barnacles.

In the Coit Tower in San Francisco, Victor Arnautoff—inspired by Diego Rivera—painted a mural that depicts a life on the streets of the city. The painting, called City Life, is done in muted blues and rusts and tans and in Rivera's Depression-era style. In the background, streets stretch off toward oblivion. In the foreground is daily life in the city.

A police officer is placing a call to headquarters; a man is reading a newspaper; two uniformed sailors are making their way toward the pier; another man is unloading crates of food next to piles of carrots and lettuce; women are holding hands with their children and moving toward the shops; other men and women move between tasks; a man collects the mail while another has his pocket picked as he checks the time; truckloads of grain arrive nearby; an elevated trolley carries people downtown as trainloads of cargo arrive in the rail yards; factories belch smoke; a fire truck races to a blaze; and women stand on the paved walks and share stories. Although it seems chaotic, it intertwines as artfully as a symphony or a colony of ants. Some provide food, some eat, some transport, some collect, and others defend. And each relies on the other, each depends on the rest. Move one, and the sense of what is happening changes.

Inside every one of us, such a scene is played out day after day after day. Intestines deliver foodstuffs, eyes bring the news, the immune system keeps track of the bad guys, the liver cleans the water, and the red blood cells purify the air. The mind worries. The blood flows.

Like City Life, each of those inside us relies wholly on each of the others. But unseen in Arnautoff's mural is the true mass of humanity. Inside humans one group stands out from all the rest, outnumbers all the others taken together— bacteria, the ground stuff of life. Underneath and in between every human brick, bacteria thrive. And they mortar it all together.

Our bacteria are not barnacles; they're not just along for the ride. Our bacteria are paying passengers.

And every day we give away a few million and we acquire a few million and— as what we see or hear, as surely as whom we meet or what we eat, as surely as what we wear—those bacteria change us, change what we can do and change who we are. Sometimes, as with syphilis, the change is obvious, other times less so. But there is always change.

My uncle Henry lost his mind because of that—a fling in France, a bacterium—a change. Untold thousands of others have lost their lives because of a single breath of air, a fleabite, a drink of water, a wound, and Mycobacterium tuberculosis (TB), Yersinia pestis(bubonic plague), Vibrio cholerae (cholera), or Clostridium botulinum (botulism)—all bacteria.

We notice that. Bacteria reach out and slap us in the face then. It's in the papers, the magazines. It's on TV. It's the reason we thought we went after Saddam Hussein—agents of death and disease, that's what bacteria are. And sometimes that's true. Some bacteria do make us sick and kill us. But that's only part of the story, only the tiniest part.

It's true that bacteria took my uncle Henry's eyes, then his legs, and finally his life. And that's a terrible story. It is impossible to say, of course, just what the bacteria may have given my uncle. But surely they did give him something, surely. And then there's all the rest, the bacteria that gave Henry life to begin with—a considerable gift—and those that sustained him. And it wasn't bacteria that sent Henry off to war. That was Woodrow Wilson. Who knows what was infecting him.

At the end, Beethoven, too, had trillions of companions with him—as he composed, as he slept, as he bathed—constant companions.

Like Henry, among Beethoven's companions was T. pallidum, a microscopic spiral-shaped bacterium. In concert with the spirochete and all the Others, Beethoven wrote his Ninth and final symphony—the first ever to Incorporate the human voice—after he could no longer hear a single note of what he wrote.

According to a study completed in the 1900s, a common feature of tertiary syphilis is auditory hallucinations. And among the most common of these auditory hallucinations are intricate and prolonged pieces of music.

None of us can know for certain which of the notes and phrases, the percussion, and the crescendos (unusual for Beethoven) of the Ninth Symphony were whispered into Beethoven's deaf ears by T. pallidum. But they are there, those notes, for certain, they are there. Just as are all the others sung to him by the swarm of life that was Beethoven. All we need do is listen for them.