Alarm receptors inside your mouth will tell you to drop a spoonful of soup before it burns your tongue, but, oddly, chili peppers in salsa contain a chemical, capsaicin, that irritates those receptors, too. Peppermint cools your mouth because minty menthol seizes up cold receptors, leaving you shivering as if an arctic blast just blew through. Elements pull similar tricks with smell and taste. If someone spills the tiniest bit of tellurium on himself, he will reek like pungent garlic for weeks, and people will know he’s been in a room for hours afterward. Even more baffling, beryllium, element four, tastes like sugar. More than any other nutrient, humans need quick energy from sugar to live, and after millennia of hunting for sustenance in the wild, you’d think we’d have pretty sophisticated equipment to detect sugar. Yet beryllium—a pale, hard-to-melt, insoluble metal with small atoms that look nothing like ringed sugar molecules—lights up taste buds just the same.
This disguise might be merely amusing, except that beryllium, though sweet in minute doses, scales up very quickly to toxic.* By some estimates, up to one-tenth of the human population is hypersusceptible to something called acute beryllium disease, the periodic table equivalent of a peanut allergy. Even for the rest of us, exposure to beryllium powder can scar the lungs with the same chemical pneumonitis that inhaling fine silica causes, as one of the great scientists of all time, Enrico Fermi, found out. When young, the cocksure Fermi used beryllium powder in experiments on radioactive uranium. Beryllium was excellent for those experiments because, when mixed with radioactive matter, it slows emitted particles down. And instead of letting particles escape uselessly into the air, beryllium spikes them back into the uranium lattice to knock more particles loose. In his later years, after moving from Italy to the United States, Fermi grew so bold with these reactions that he started the first-ever nuclear chain reaction, in a University of Chicago squash court. (Thankfully, he was adept enough to stop it, too.) But while Fermi tamed nuclear power, simple beryllium was doing him in. He’d inadvertently inhaled too much of this chemists’ confectioner’s powder as a young man, and he succumbed to pneumonitis at age fifty-three, tethered to an oxygen tank, his lungs shredded.
Beryllium can lull people who should know better in part because humans have such a screwy sense of taste. Now, some of the five types of taste buds are admittedly reliable. The taste buds for bitter scour food, especially plants, for poisonous nitrogen chemicals, like the cyanide in apple seeds. The taste buds for savory, or umami, lock onto glutamate, the G in MSG. As an amino acid, glutamate helps build proteins, so these taste buds alert you to protein-rich foods. But the taste buds for sweet and sour are easy to fleece. Beryllium tricks them, as does a special protein in the berries of some species of plants. Aptly named miraculin, this protein strips out the unpleasant sourness in foods without altering the overtones of their taste, so that apple cider vinegar tastes like apple cider, or Tabasco sauce like marinara. Miraculin does this both by muting the taste buds for sour and by bonding to the taste buds for sweet and putting them on hair-trigger alert for the stray hydrogen ions (H+) that acids produce. Along those same lines, people who accidentally inhale hydrochloric or sulfuric acid often recall their teeth aching as if they’d been force-fed raw, extremely sour lemon slices. But as Gilbert Lewis proved, acids are intimately bound up with electrons and other charges. On a molecular level, then, “sour” is simply what we taste when our taste buds open up and hydrogen ions rush in. Our tongues conflate electricity, the flow of charged particles, with sour acids. Alessandro Volta, an Italian count and the inspiration for the eponym “volt,” demonstrated this back around 1800 with a clever experiment. Volta had a number of volunteers form a chain and each pinch the tongue of one neighbor. The two end people then put their fingers on battery leads. Instantly, up and down the line, people tasted each other’s fingers as sour.
The taste buds for salty also are affected by the flow of charges, but only the charges on certain elements. Sodium triggers the salty reflex on our tongues most strongly, but potassium, sodium’s chemical cousin, free rides on top and tastes salty, too. Both elements exist as charged ions in nature, and it’s mostly that charge, not the sodium or potassium per se, that the tongue detects. We evolved this taste because potassium and sodium ions help nerve cells send signals and muscles contract, so we’d literally be brain-dead and our hearts would stop without the charge they supply. Our tongues taste other physiologically important ions such as magnesium and calcium* as vaguely salty, too.
Of course, taste being so complicated, saltiness isn’t as tidy as that last paragraph implies. We also taste physiologically useless ions that mimic sodium and potassium as salty (e.g., lithium and ammonium). And depending on what sodium and potassium are paired with, even they can taste sweet or sour. Sometimes, as with potassium chloride, the same molecules taste bitter at low concentrations but metamorphose, Wonka-like, into salt licks at high concentrations. Potassium can also shut the tongue down. Chewing raw potassium gymnemate, a chemical in the leaves of the plant Gymnema sylvestre, will neuter miraculin, the miracle protein that turns sour into sweet. In fact, after chewing potassium gymnemate, the cocaine-like rush the tongue and heart usually get from glucose or sucrose or fructose reportedly fizzles out: piles of raw sugar heaped on the tongue taste like so much sand.*
All of this suggests that taste is a frighteningly bad guide to surveying the elements. Why common potassium deceives us is strange, but perhaps being overeager and over-rewarding our brain’s pleasure centers are good strategies for nutrients. As for beryllium, it deceives us probably because no human being ever encountered pure beryllium until a chemist isolated it in Paris after the French Revolution, so we didn’t have time to evolve a healthy distaste for it. The point is that, at least partially, we’re products of our environment, and however good our brains are at parsing chemical information in a lab or designing chemistry experiments, our senses will draw their own conclusions and find garlic in tellurium and powdered sugar in beryllium.
Taste remains one of our primal pleasures, and we should marvel at its complexity. The primary component of taste, smell, is the only sense that bypasses our logical neural processing and connects directly to the brain’s emotional centers. And as a combination of senses, touch and smell, taste digs deeper into our emotional reservoirs than our other senses do alone. We kiss with our tongues for a reason. It’s just that when it comes to the periodic table, it’s best to keep our mouths shut.
A live body is so complicated, so butterfly-flaps-its-wings-in-Brazil chaotic, that if you inject a random element into your bloodstream or liver or pancreas, there’s almost no telling what will happen. Not even the mind or brain is immune. The highest faculties of human beings—our logic, wisdom, and judgment—are just as vulnerable to deception with elements such as iodine.
Perhaps this shouldn’t be a surprise, since iodine has deception built into its chemical structure. Elements tend to get increasingly heavy across rows from left to right, and Dmitri Mendeleev decreed in the 1860s that increasing atomic weight drives the table’s periodicity, making increasing atomic weight a universal law of matter. The problem is that universal laws of nature cannot have exceptions, and Mendeleev’s craw knew of a particularly intractable exception in the bottom right-hand corner of the table. For tellurium and iodine to line up beneath similar elements, tellurium, element fifty-two, must fall to the left of iodine, element fifty-three. But tellurium outweighs iodine, and it kept stubbornly outweighing it no matter how many times Mendeleev fumed at chemists that their weighing equipment must be deceiving them. Facts is facts.
Nowadays this reversal seems a harmless chemical ruse, a humbling joke on Mendeleev. Scientists know of four pair reversals among the ninety-two natural elements today—argon-potassium, cobalt-nickel, iodine-tellurium, and thorium-protactinium—as well as a few among the ultraheavy, man-made elements. But a century after Mendeleev, iodine got caught up in a larger, more insidious deception, like a three-card monte hustler mixed up in a
Mafia hit. You see, a rumor persists to this day among the billion people in India that Mahatma Gandhi, that sage of peace, absolutely hated iodine. Gandhi probably detested uranium and plutonium, too, for the bombs they enabled, but according to modern disciples of Gandhi who want to appropriate his powerful legend, he reserved a special locus of hatred in his heart for element fifty-three.
In 1930, Gandhi led the Indian people in the famous Salt March to Dandi, to protest the oppressive British salt tax. Salt was one of the few commodities an endemically poor country such as India could produce on its own. People just gathered seawater, let it evaporate, and sold the dry salt on the street from burlap sacks. The British government’s taxing of salt production at 8.2 percent was tantamount in greed and ridiculousness to charging bedouins for scooping sand or Eskimos for making ice. To protest this, Gandhi and seventy-eight followers left for a 240-mile march on March 12. They picked up more and more people at each village, and by the time the swelling ranks arrived in the coastal town of Dandi on April 6, they formed a train two miles long. Gandhi gathered the throng around him for a rally, and at its climax he scooped up a handful of saline-rich mud and cried, “With this salt I am shaking the foundation of the [British] Empire!” It was the subcontinent’s Boston Tea Party. Gandhi encouraged everyone to make illegal, untaxed salt, and by the time India gained independence seventeen years later, so-called common salt was indeed common in India.
The only problem was that common salt contains little iodine, an ingredient crucial to health. By the early 1900s, Western countries had figured out that adding iodine to the diet is the cheapest and most effective health measure a government can take to prevent birth defects and mental retardation. Starting with Switzerland in 1922, many countries made iodized salt mandatory, since salt is a cheap, easy way to deliver the element, and Indian doctors realized that, with India’s iodine-depleted soil and catastrophically high birthrate, they could save millions of children from crippling deformities by iodizing their salt, too.
But even decades after Gandhi’s march to Dandi, salt production was an industry by the people, for the people, and iodized salt, which the West pushed on India, retained a whiff of colonialism. As the health benefits became clearer and India modernized, bans on non-iodized salt did spread among Indian state governments between the 1950s and 1990s, but not without dissent. In 1998, when the Indian federal government forced three holdout states to ban common salt, there was a backlash. Mom-and-pop salt makers protested the added processing costs. Hindu nationalists and Gandhians fulminated against encroaching Western science. Some hypochondriacs even worried, without any foundation, that iodized salt would spread cancer, diabetes, tuberculosis, and, weirdly, “peevishness.” These opponents worked frantically, and just two years later—with the United Nations and every doctor in India gaping in horror—the prime minister repealed the federal ban on common salt. This technically made common salt legal in only three states, but the move was interpreted as de facto approval. Iodized salt consumption plummeted 13 percent nationwide. Birth defects climbed in tandem.
Luckily, the repeal lasted only until 2005, when a new prime minister again banned common salt. But this hardly solves India’s iodine problem. Resentment in Gandhi’s name still makes people seethe. The United Nations, hoping to inculcate a love of iodine in a generation with less of a tie to Gandhi, has encouraged children to smuggle salt from their home kitchens to school. There, they and their teachers play chemistry lab by testing for iodine deficiencies. But it’s been a losing battle. Although it would cost India just a penny per person per year to produce enough iodized salt for its citizens, the costs of transporting salt are high, and half the country—half a billion people—cannot currently get iodized salt regularly. The consequences are grim, even beyond birth defects. A lack of trace iodine causes goiter, an ugly swelling of the thyroid gland in the neck. If the deficiency persists, the thyroid gland shrivels up. Since the thyroid regulates the production and release of hormones, including brain hormones, the body cannot run smoothly without it. People can quickly lose mental faculties and even regress to mental retardation.
English philosopher Bertrand Russell, another prominent twentieth-century pacifist, once used those medicinal facts about iodine to build a case against the existence of immortal souls. “The energy used in thinking seems to have a chemical origin…,” he wrote. “For instance, a deficiency of iodine will turn a clever man into an idiot. Mental phenomena seem to be bound up with material structure.” In other words, iodine made Russell realize that reason and emotions and memories depend on material conditions in the brain. He saw no way to separate the “soul” from the body, and concluded that the rich mental life of human beings, the source of all their glory and much of their woe, is chemistry through and through. We’re the periodic table all the way down.
Part IV
THE ELEMENTS OF HUMAN CHARACTER
12
Political Elements
The human mind and brain are the most complex structures known to exist. They burden humans with strong, complicated, and often contradictory desires, and even something as austere and scientifically pure as the periodic table reflects those desires. Fallible human beings constructed the periodic table, after all. Even more than that, the table is where the conceptual meets the grubby, where our aspirations to know the universe—humankind’s noblest faculties—have to interact with the material matter that makes up our world—the stuff of our vices and limitations. The periodic table embodies our frustrations and failures in every human field: economics, psychology, the arts, and—as the legacy of Gandhi and the trials of iodine prove—politics. No less than a scientific, there’s a social history of the elements.
That history can best be traced through Europe, starting in a country that was as much of a pawn for colonial powers as Gandhi’s India. Like a cheap theater set, Poland has been called a “country on wheels” for all its exits and entrances on the world stage. The empires surrounding Poland—Russia, Austria, Hungary, Prussia, Germany—have long held war scrimmages on this flat, undefended turf and have taken turns carving up “God’s playground” politically. If you randomly select a map from any year in the past five centuries, the odds are good that Polska (Poland) will be missing.
Fittingly, Poland did not exist when one of the most illustrious Poles ever, Marie Skłodowska, was born in Warsaw in 1867, just as Mendeleev was constructing his great tables. Russia had swallowed Warsaw up four years earlier after a doomed (as most Polish ones were) revolt for independence. Tsarist Russia had backward views on educating women, so the girl’s father tutored her himself. She showed aptitude in science as an adolescent, but also joined bristly political groups and agitated for independence. After demonstrating too often against the wrong people, Skłodowska found it prudent to move to Poland’s other great cultural center, Krakow (which at the time, sigh, was Austrian). Even there, she could not obtain the science training she coveted. She finally moved to the Sorbonne in faraway Paris. She planned to return to her homeland after she earned a Ph.D., but upon falling in love with Pierre Curie, she stayed in France.
In the 1890s, Marie and Pierre Curie began perhaps the most fruitful collaboration in science history. Radioactivity was the brilliant new field of the day, and Marie’s work on uranium, the heaviest natural element, provided a crucial early insight: its chemistry was separate from its physics. Atom for atom, pure uranium emitted just as many radioactive rays as uranium in minerals because the electron bonds between a uranium atom and the atoms surrounding it (its chemistry) did not affect if or when its nucleus went radioactive (its physics). Scientists no longer had to examine millions of chemicals and tediously measure the radioactivity of each (as they must do to figure out melting points, for instance). They needed to study only the ninety-some elements on the periodic table. This vastly simplified the field, clearing away the distracting cobwebs and revealing the wooden beam holding up the edifice. The Curies shared the 1903 Nobel Prize in Physics for
making this discovery.
During this time, life in Paris satisfied Marie, and she had a daughter, Irène, in 1897. But she never stopped viewing herself as Polish. Indeed, Curie was an early example of a species whose population exploded during the twentieth century—the refugee scientist. Like any human activity, science has always been filled with politics—with backbiting, jealousy, and petty gambits. Any look at the politics of science wouldn’t be complete without examples of those. But the twentieth century provides the best (i.e., the most appalling) historical examples of how the sweep of empires can also warp science. Politics marred the careers of probably the two greatest women scientists ever, and even purely scientific efforts to rework the periodic table opened rifts between chemists and physicists. More than anything, politics proved the folly of scientists burying their heads in lab work and hoping the world around them figured out its problems as tidily as they did their equations.
Not long after her Nobel Prize, Curie made another fundamental discovery. After running experiments to purify uranium, she noticed, curiously, that the leftover “waste” she normally discarded was three hundred times more radioactive than uranium. Hopeful that the waste contained an unknown element, she and her husband rented a shed once used to dissect corpses and began boiling down thousands of pounds of pitchblende, a uranium ore, in a cauldron and stirring it with “an iron rod almost as big as myself,” she reported, just to get enough grams of the residue to study properly. It took years of oppressively tedious work, but the labor culminated in two new elements—and was consummated with, since they were elements far, far more radioactive than anything known before, another Nobel Prize in 1911, this one in chemistry.
Sam Kean Page 18
