From the Publisher
"A brilliant, feisty scientist at the center of a nasty, back-stabbing, utterly absorbing, cliff-hanging scramble for the Nobel Prize. The Emperor of Scent is a quirky, wonderful book."
-John Berendt, author of Midnight in the Garden of Good and Evil
"Professional perfume critic, obsessive collector of rare fragrances, academic-bad-boy biochemist and world-class eccentric, Luca Turin would be the worthy subject of a book even if he hadn't come up with a revolutionary scientific theory. Written with skill and verve, The Emperor of Scent is an engrossing intellectual detective story about one iconoclast's quest to solve a centuries-old mysteryhow smell works."
-Miles Harvey, author of The Island of Lost Maps
"The Emperor of Scent is a gem of a booka suspense story at whose heart is a man of super-human powers who is also flawed and justifiably arrogant and dangerously steeped in hubris. I challenge any intelligent, curious mind not to tumble into this story and find themselves immediately engrossed. I fell in love with Luca Turinhe is everything I admire in a human: irreverent, witty, imaginative, determined, elitist without a trace of snobbery and above all a creative genius. And Chandler Burr is a magician himself, and a man we should all be so lucky to have at a dinner party: I was mesmerized and enlightened by the many perfect asides woven into the main body of this incredible true tale."
-Alexandra Fuller, author of Don't Let's Go to the Dogs Tonight
“What happens when Luca Turin, a likable scientist who happens to possess an unusually sensitive nose, proposes a new theory of smell that promises to unravel the mystery [of scent] once and for all? That’s what readers find out in this often funny, picaresque exposé of the closed world of whiffs, aromas and odors—and the people who study them.”
—Publishers Weekly (starred review)
“Exhibiting more grace than a magician in tails, Chandler Burr brings science and the people who practice it to life in The Emperor of Scent. . . . Burr does a remarkable job of explaining both Turin, the man behind the idea, and his science.”
—The Denver Post
“Chandler Burr . . . has transformed a chance meeting with a curious biophysicist named Luca Turin into an amusing and poetic adventure in science and art.”
—The Washington Post
The story of an obsessed scientist and his controversial quest for a unified theory of smell.
The smell industry generates $11 billion a year. That's what's spent on olfactory ingredients in Tide detergent, Palmolive soap, Chanel No. 5 and a host of other aromatic products. Yet as author Chandler Burr points out in his ele-gant new book, The Emperor of Scent (Random House, $25), chemists toiling at the industrial conglomerates that produce scents have been engaged in educated guesswork: No one has understood how the sense of smell really works.
Until, perhaps, now. Burr thinks he's found the man who has solved the mystery: Luca Turin, an eccentric sci-entist whose nose has the olfactory equivalent of perfect pitch. Burr's book is an acutely entertaining profile of Turin. But it is also an illustration of what happens when a maverick scientific theory threatens conventional wisdom.
Until Turin came along, most people thought scent came from a molecule's shape. Each molecule has a unique configuration of bumps and curves. When a lemon's citral molecule, for instance, hits the receptors in our noses, those receptors recognize the particular ridges and valleys, and can provide our brain with one clue about the identity of the fruit being sniffed.
Turin, though, doesn't buy the shape theory. It is molecular vibrations, he insists, that are responsible for smell. A scientific polymath with a Ph.D. in physiology and biophysics from the University of London, Turin also has a rare-fied hobby: perfume. Even as a child growing up in Geneva and Paris, he was interested in it. Early in his scientific ca-reer he landed a research post in Nice, close to the great perfume center ofGrasse. There he indulged his obsession, scouring the region for out-of-circulation fragrances to add to his personal collection.
Turin's passion led him to write the first-ever perfume guide, a kind of Zagat's for the nose. Called, simply, Parfums:Le Guide, it appeared in 1992, became a French bestseller, and is currently out of print.
Turin had great fun penning his reviews, giving raves to fragrances he liked ("Thanks to Rive Gauche, mortals can at last know the scent of the goddess Diana's bath soap") and slamming those he hated ("57 for Her is a sad little thing, an incongruous dried-prunes note with a metallic edge that manages the rare feat of being at once cloying and harsh"). But the most startling thing about Turin's guide was the precision with which he translated a sensual experience into words (Gucci's Rush "smells like an infant's breath mixed with his mother's hair spray").
The book caught the attention of perfume manufacturers, who invited him inside their secret labs. At Quest In-ternational, the England-based conglomerate that is one of the seven large fragrance producers in the world, Turin ob-served that the creation of new smell molecules was little more than costly trial and error. Environmental and toxicology testing for one new smell molecule can run upwards of $250,000.
Shortly after publishing his book Turin happened on an article about a gadget that analyzed molecules, called an electron-tunneling spectroscope. A lightbulb went on in his head. He remembered an earlier article he'd read about a radical--though discredited--theory: that smell came not from a molecule's shape, but from its vibration. The only in-struments capable of measuring such vibrations, though, were spectroscopes--4-foot-long glass-and-metal optical de-vices that used infrared light. Imagining one made of human flesh seemed absurd.
The device described in the more recent article, however, did not use optics. It used electrons to measure a molecule's electrical charge. Turin's theory: that nasal receptors were tiny spectroscopes, measuring vibration by meas-uring electron current.
The most appealing thing about Turin's hypothesis was that he was now able to develop an algorithm that could predict smell from vibrational data. Commercially available quantum chemistry software could calculate the frequency. But Turin needed to calculate intensity of vibration as well. Interested parties can find one version of the resulting algo-rithm in Burr's book, though Turin says he's since refined it.
If Burr is to be believed, Turin can punch the structure of a molecule into a computer and in 48 hours get smell predictions for 3,000 variations. For instance, chemists have not yet figured out an easy way to make a synthetic patch-ouli scent. If Turin wanted to work on this using his algorithm, he'd start with one of patchouli's components--say, a molecule that smells earthy or woody--and try varying its structure in small ways. His computer would tell him which combinations were most likely to smell like the real thing. The old, more costly and time-consuming way of inventing smells requires chemists to make molecules and then sniff them. About two new molecules a week can be tested, at a cost of up to $3,000 each.
Obviously the Big Seven were intrigued. So was the scientific community. But Turin's work challenged the status quo in such a profound way that smell specialists had a tough time believing he was correct.
Where was his proof? Turin found plenty of molecules that were shaped the same but smelled different, thus throwing doubt on the shape theory. But it's tougher to prove a positive--to predict from a molecule's vibrational struc-ture exactly how it will smell--and he struggled to concoct an experiment that would satisfy his scientific and industrial peers.
Turin tried unsuccessfully for a year to publish an article in the British science journal Nature. A BBC documentary about his quest, aptly titled A Code in the Nose, finally lit a fire under the Big Boys, two of whom asked him to do some molecule testing. Ultimately, though, they declined to apply his theories.
Why? Here Burr gets a bit carried away: The rejection of the vibration theory is because of "scientific corrup-tion, corruption in the most mundane and systemic and virulent and sadly human sense of jealousy and calcified minds and vested interests." Could it be, perhaps, that skeptics are simply waiting for better proof?
Since Burr finished research on his book, Turin has become chief scientist at Flexitral, a new privately held company in Chantilly, Va., where he is concocting fragrance and flavor molecules. After just one year, and with an in-vestment of less than $1 million from private individuals outside the fragrance industry, Flexitral has come up with two products.
One is a stable lemon-flavor molecule called Acitral. The most commonly used lemon-flavor molecule, citral, fades within 30 days when put in an acid medium like lemonade. The citral molecule has a double bond in its tail, which, when it comes into contact with acid, forms a circular structure. Once citral gets into this circular form, it loses its lemony scent and starts to stink. Acitral, according to Turin, has no double bond and lasts longer.
The second is a molecule bearing a lily of the valley scent, much used in fresh floral fragrances. Turin says he's on his way to closing a licensing deal with one of the Big Boys for it. If he collects royalties on either product, his com-petitors in academia and industry may wake up and smell the profits.
Read an Excerpt
Start with the deepest mystery of smell. No one knows how we do it.
Despite everything, despite the billions the secretive giant corporations of smell have riding on it and the powerful computers they throw at it, despite the most powerful sorcery of their legions of chemists and the years of toiling in the labs and all the famous neurowizardry aimed at mastering it, the exact way we smell things–anything, crushed raspberry and mint, the subway at West
Fourteenth and Eighth, a newborn infant–remains a mystery. Luca Turin began with that mystery.
Or perhaps he began further back, with the perfumes. “The reason I got into this,” Turin will say, “is that I started collecting perfume. I’ve loved perfume from when I was a kid in Paris and Italy.”
Or maybe (he’ll tell you another day, considering it from a different angle), maybe it was “because I’m French, at least by upbringing.
Frenchmen will do things Anglo men won’t, and France is a country of smells. There’s something called pourriture noble. Noble rot. It’s a fungus. It grows on grapes, draws the water out, concentrates the juice wonderfully, adds its own fungal flavor, and then you make wines like the sweet Sauternes. Paradise. From rotten grapes. The idea that things should be slightly dirty, overripe, slightly fecal is everywhere in
France. They like rotten cheese and dirty sheets and unwashed women. Guy
Robert is about seventy, a third-generation perfumer, lives in the south of France, used to work for International Flavors & Fragrances, created
Calèche for Hermès. One day he asked me, ‘Est-ce que vous avez senti some molecule or other?’ And I said no, I’d never smelled it, what’d it smell like? And he considered this gravely and replied, ‘ça sent la femme qui se néglige.’ ” (It smells of the woman who neglects herself.)
This makes him remember something, and he leans forward enthusiastically. “One of the stories I heard when I started meeting the perfumers and was let into their tightly closed world involves Jean
Carles, one of the greatest perfume makers in Paris–he used to work for
Roure in Grasse, near Nice, where all perfumes used to be made. He became anosmic, lost his sense of smell, and he simply carried on from memory, creating perfumes. Like Beethoven after his deafness. Jean
Carles went on to create the great Ma Griffe for Carven, a result of pure imagination in the complete absence of the relevant physical sense.
Carles’s condition was known only to him and his son. When a client came in, he’d go through the motions, make a big show of smelling various ingredients and, finally, the perfume he had created, which he would present with great gravity to the client, smelling it and waving its odor around the room. And he couldn’t smell anything!” Turin smiles,
thinking about it.
The perfume obsession led Turin to write the perfume guide, which out of the blue cracked open for him doors into the vast, secret world in which perfumes are created, and there he started noticing little things that didn’t make sense. A weird warp in official reality. Plus there were the other clues, the small pockets of strangeness he bumped into in the scientific literature, carefully fitting these into the puzzle without even realizing it, without (as he’d be the first to admit) really understanding what he was doing. And somewhere along the line, between scouring the French Riviera for bottles of buried fragrances, pursuing
(in his own very particular way) the strange triplets of biology and chemistry and physics, and prowling the library’s remotest stacks,
randomly sliding into things he found there–something that due to his intellectual promiscuity he does a lot of–somewhere Luca Turin got the idea of cracking smell. But it started with the mystery at smell’s heart, which is not only that we don’t know how we do it. We actually shouldn’t be able to smell at all.
From everything we know about evolution and molecular biology, smell does the impossible. Look at two other systems inside your body, and you’ll understand.
First, digestion. Human beings have evolved over millennia while eating certain molecules–lipids and carbohydrates and proteins in the roots and berries and various unlucky animals we’ve gotten our hands on. The tiny carbs and proteins are made of tinier atoms and molecules, and for your body to burn them as various fuels, evolution has engineered a digestive system for you. The system’s first task is to recognize which raw fuel it’s dealing with, so it can send out the right enzymes to break that fuel down, process it for us. (Enzymes are catalysts, molecule wranglers, and every enzyme in every one of our cells–and there are tens of thousands of different enzymes–binds to a molecule and processes it.
Some break molecules down, scrapping them to use their dismantled parts,
some zip them together, and some rearrange them for the body’s own purposes.) But in every case the enzyme “recognizes” its molecule by that molecule’s particular shape. Fat, thin, lumpy, rounded, oblong,
rectangular. The enzyme feels some cleft in some molecule, fits its special fingers into it like a key fits into a lock. And if the shape of the lock and the shape of the key conform, bingo: Recognition! By shape.
And what gives a molecule its shape? We think of atoms as these perfectly symmetrical spheres, shining and frozen on labels of
“Super-Strong!” kitchen cleaners, their electrons zipping around their nuclei like perfectly spherical stainless-steel bracelets. Since electrons move at close to the speed of light, if you filmed those cartoon atoms in motion you’d see a round electron membrane, a solid,
buzzing sphere made of blisteringly fast-moving electrons.
But that’s kitchen-cleaner labels. The skins of atoms are actually made of the paths of their outermost electrons, but not only don’t they zip around in perfectly circular orbits, they carve an almost infinite variety of 3-D orbital grooves around their nuclei. If that’s not enough, atoms get shoved against and glued to one another in molecules,
forming bulbous structures, or nonspherical structures with disks and oblongs. Imagine taking the giant inflatable balloons in the Macy’s parade, each one shaped differently, and pushing them against one another; their skins smoosh and warp, their bulbs and crevices contract and expand. So the electrons zip along in these new configurations, in elongated ellipses and valleys and sharp peaks and strange arcs. Which means that each molecule creates a unique shape that an enzyme can recognize as precisely as a retinal scan.
In fact, molecular recognition is arguably the fundamental mechanism of all life, and it is based on this single, universal principle: Shape.
Receptor cells from your head to your glands and skin recognize enzymes,
hormones, and neurotransmitters by their molecular shapes. The only variable is time.
The thing about enzymes is that evolution has learned over millennia that you’re going to need to digest (break down, make up, or molecularly rearrange) certain things–wild almonds and crab apples and dead squirrels (sugars, fats, and proteins)–and not others–raw petroleum or sand or silicate (fluorocarbons and borazines). So evolution has by now selected for you a complete, fixed genetic library of enzymes that will bind to and deal with a fixed list of molecules. (It’s not an exact one-to-one enzyme-to-foodstuff ratio, but it’s precise enough that it’s why your dog famously can’t digest chocolate, a culinary product his wolf ancestors never ate: evolution never selected for dogs an enzyme that recognized the shape of chocolate’s molecules, so if you feed them these molecules, they get sick.) And if just one enzyme is missing, you end up with nasty, sometimes lethal, diseases and disorders. You can dump the squirrels for terrine de lapin et petits légumes, it doesn’t matter: it’s the same lipids and proteins in your library, and as long as you don’t eat, say, plastic, for which you have no enzyme, your digestive system happily recognizes the molecules you consume, be it
McDonald’s or the fifth course at the Clifton Inn. The thing to remember here, however, is time: enzymes stand ready to identify the right molecule instantly.
For contrast, take the immune system. Antibodies are designed (they have to be) to bind to things that weren’t around our ancestors, unknown bacteria and foreign parasites and each year’s new, nastier, mutated viruses we’ve never seen before. Your visual system can recognize things that weren’t in Homo sapiens’s evolutionary environment, like Ferraris and Star Wars and Barbra Streisand, and so can your immune system, but your visual system deciphers photon wavelengths while your immune system is feeling out molecules’ shapes. Here’s the difference. When it encounters a new virus, the immune system starts rapidly rearranging genes at random, spewing out antibodies until it hits on one that fits the invader’s shape, binds to it, and destroys it. (It’s the exact opposite of a “fixed library” idea; Susumu Tonegawa of MIT won a 1987
Nobel Prize for figuring this out.) So that’s why you’re at home for a few days with the flu. Your immune system needs time to break the invader’s shape code and produce the shape weapon to fight it. Where the digestive system is limited but instant, the immune system is unlimited–it “takes all comers”; but it also takes time.
But here is the problem. Someone hands you a molecule called a borane.
You lift it to your nose. And without fail, you smell it. There’s just one catch: boranes were created by inorganic chemists at the beginning of the twentieth century and never existed in the ancestral environment of any human being. Yet we smell them. This is impossible.
The fact is that we have never found any molecule in the smellable size range that we could not smell instantly. This is the mystery of smell.
You smell boranes instantly, not in a few days or weeks, even though you cannot have an evolutionarily selected receptor molecule for their unique shape. Smell is unlimited, like the immune system, and yet it is instant, like the digestive system. And everything we know about Shape and molecular recognition says this should be impossible.
We understand the human sense of vision intimately, down to exactly which vibration of a particle of light caught in the vision receptor in the retina will make us see exactly which color (a 1967 Nobel given for vision). We know hearing in exquisite detail, can predict with absolute accuracy which air vibration in the cochlea will create what tone (a
1961 Nobel for hearing). But of smell, we do not know, cannot predict.
This is why smell is the object of two cut-throat races.
The first is scientific. This all-out race is being run in some of the most powerful labs (by the most competitive researchers with the biggest egos). The prize is the unscrambling of one of the most important secrets of biology, not to mention (everyone is betting on this) a Nobel
Prize. An astounding 1 percent of human genes, we recently discovered,
are devoted to olfaction. “So smell must be incredibly important for us,” notes NIH geneticist Dean Hamer, “to devote so much of our DNA to it. The only comparable system–and this was the big surprise to everyone–is the immune system, and we all know why it’s important to fight off invaders. This says smell was central in our evolution in a way that, presently, we don’t really understand.”
The other race is for money. Approximately $20 billion is generated every year by industrially manufactured smells, and virtually all these smells are made by only seven companies, the Big Boys, which split the billions among themselves. The Big Boys shroud themselves in secrecy to protect the public brand image of their clients. They make the molecules that you associate with the smells of Tide laundry detergent, Clorox bleach, and Palmolive soap, but they are also the actual creators of the superexpensive fragrances sold under the rarefied labels Calvin Klein and Chanel and L’Oréal, Miyake and Armani. The creation of a single commercially successful fragrance molecule represents tens of millions of dollars, and the Big Boys employ an army of chemists tasked with creating them. The way to create them is the magic formula.
This is why Luca Turin’s theory is as important as it is unknown. It is not only a new theory of smell. Financially, it implies a technology that threatens thousands of engineers and corporate executives, the investment of billions of dollars, and the industrial structures of massive corporations in North America, Europe, and Japan.
Scientifically, it is a wildly revolutionary proposal contradicting a universal, bedrock assumption of biology–Shape–and positing an astounding, microscopic electrical mechanism that operates inside the human body and is made of human flesh. You might as well, fumed one furious scientist who heard about Turin’s idea, propose a new theory of digestion through tiny nuclear reactors in people’s stomachs. Perhaps the only thing odder than the theory is the story of how Turin actually came up with it, and then of what happened to him when he did, which is what this book is about.