The Emperor of Scent is the “Story of Perfume, Obsession, and the Last Mystery of the Senses” under the guise of a biography of Luca Turin. At the time the book was written, Luca Turin was a lecturer at University College London in the department of physiology working on a theory of how the body perceives smell. Had Luca Turin won the Nobel Prize for unraveling the mystery of smell, the book might have been a bigger seller and Turin an international celebrity.
Many biographies are written after someone dies. Luca Turin is very much alive. In Hollywood they would say “We are still in the second act.”, but this real story has much more drama than most fiction. While Turin’s theory of smell is probably correct, it has been rejected as nonsense by nearly every important researcher in the field. The author approached one scientist asking about Turin’s theory and got the response “So basically, if he’s right, he’s a genius, and we’re all assholes working on garbage.”
The drama revolves around Luca Turin’s three struggles. The first is the struggle of a scientist. Several times in the book he runs experiments where a contrary result would completely contradict his theory. In this contest he triumphs. The second struggle is with the scientific community. He can’t even get anybody to read his papers much less take them seriously. In this struggle he is a dismal failure. His ideas are not even given a hearing. His third struggle is with the perfume industry. This struggle continues today.
Luca Turin has a passion for life in general and smells and perfumes in specific. He has a gift for writing about perfumes. Much of the joy of the book is reading Turin’s perfume reviews. The author, Chandler Burr points out that Turin’s perfume reviews are mostly nouns with very few adjectives. I suspect Turin’s writing has had a positive effect on Burr as his descriptions are pretty good too. At times the book is a pleasure to read just because of the descriptive language irrespective of the dramatic aspects of the story.
I was given the book because I have been judging wines for more than 30 years. I’m also a pretty good cook. My sense of smell and vocabulary for smells is well trained. I am convinced that smell is both physical and cultural in the way we recognize smells. The book touches on this briefly. It is an area worthy of further exploration.
Many of Turin’s political enemies don’t believe smell is quantifiable at all. I know from wine tasting that there are many identifiable smells that are directly related to specific chemicals in wines. Though I’m not a chemist, I know specific smells are present in wines and the experience is repeatable. It is not that people can’t smell specific smells; it is a cultural thing that we learn to identify them. This is why wine tasting classes can be so useful.
Turin’s Vibration Theory of Smell
In 1938 Malcolm Dyson wrote a paper suggesting that the nose worked like a gas chromatograph. A gas chromatograph works by shining a strong light on a material and detecting how the material glows or resonates. This resonance is based on the chemical bonds and allows chemists to identify which atoms are present in a chemical compound. Each chemical bond vibrates at a specific frequency when excited by light.
I know from first hand experience that a skilled operator can use a gas chromatograph to analyze distilled spirits in order to make knockoffs of popular brandies as the elements that make up the nose of a brandy are well understood by those in the trade. I understand this tool is widely used in the perfume trade as well.
Dyson proposed a nice theory, but it was never taken seriously because the nose obviously has neither strong light sources nor light detectors.
The predominant theory for how the nose works is called the “shape” theory in that it assumes there are receptors in the nose that detect the shape of a molecule. Until Turin came along, acceptance of the shape theory of smell was universal. The attraction of the shape theory is that every known biological process works based on the recognition of the shape of molecules. This is true for digestion and the immune system and is the basis of how the pharmaceutical industry is structured. The research establishment spends billions of dollars a year working on chemistry based on the shape of molecules.
Turin points out that vision and hearing are two examples of biological sensors that don’t depend on chemical shapes to operate.
There are two problems with the shape theory of smell. The first is that nobody has found receptors that work on the basis of shape and there is much debate as to how many different receptors would be necessary to differentiate a wide range of smells. Other processes using the shape of molecules are very specific in differentiating molecules. Reactions only proceed when the shape matches exactly. There couldn’t possibly be a specific receptor for each individual smell or we wouldn’t be able to smell new molecules we create in the laboratory. The second problem is that the shape theory is worthless for predicting what something will smell like based on the shape of a molecule.
Turin proved that shape is unrelated to smell whereas the resonances in a molecule can be directly related to how a molecule can be expected to smell. One of the strongest smells in nature is the Hydrogen Sulfur bond. It smells like rotten eggs and has a vibration number of 2500. Turn went searching for other bonds that might vibrate at this frequency and found that Hydrogen Boron bond vibrates at the same frequency but has very different chemical properties. This class of chemicals is extremely toxic and unstable. It is used for rocket fuel. Turin ordered some so he could smell it. It does stink like rotten eggs just like Sulfur. Having the stuff around the lab made Turin very unpopular with his colleagues.
Many of Turin’s critics complain that he doesn’t do double blind experiments. Once Turin smelled the Boron compounds, he was convinced of the theory. Nobody in their right mind would want to be subject for any experiments that involved smelling Boron compounds.
I think his most devastating experiment to the shapist point of view was substituting Deuterium for Hydrogen in some compounds. Deuterium is Hydrogen with an extra Neutron. Chemically it is equivalent to Hydrogen. More to the point the molecule containing the Deuterium atom was exactly the same shape as a molecule containing the Hydrogen atom. Turin’s theory predicted the molecules should smell differently because the molecule resonates at a different frequency. He had no way of knowing the answer because nobody had ever formulated the compound and smelled the result. Fortunately for Turin his theory was confirmed by the experiment.
Turin believes the nose works by electron tunneling spectroscopy. In the 1980s physicists at Ford Motor Company published a paper describing a chemical spectrograph that worked with electricity rather than light. If you have a very small gap with a charge across it and a compound of the right size comes into the gap, the electron will “tunnel” through the compound and will lose an amount of energy proportional to the to the resonance of the chemical bond of the compound in the gap.
Smell receptors are believed to be based on a chemical structure known as G-protein receptors. These are long chemical chains which according to the shapists match their chemical shape to that of aromatic molecules being analyzed. Turin showed that these G-protein receptors could provide the structure necessary to support electron tunneling because they contain Zinc, a metal which would provide the necessary free electron. Turin also showed that a molecule called NADPH was also present in the smell receptor. This structure would provide the necessary electrical charge.
Turin wrote this (and more) up in an article for the prestigious journal Nature, but it was never published as the peer reviewers felt his theory was all nonsense. Turin eventually published his paper in a less prestigious journal, and he was ignored by the scientific community. Not only did he not get the Nobel Prize (prizes have been awarded for theories of vision and smell), but he could never get his views heard at mainstream scientific conferences.
At one point in the book in a section titled Author’s Note, Chandler Burr ceases telling the story to relate his first hand experiences attempting to interview other scientists studying the sense of smell. None of the people he interviewed would admit that they had read Turin's paper, and all claimed they were too busy to read it, but everybody had “heard about” Turin’s paper and dismissed it as nonsense.
It became apparent to Turin that he was never going anyplace professionally as a scientist so he turned his attention to the scent industry.
Luca Turin has a huge reputation in the perfume industry as the author of the first, best and very popular guide to perfumes. It is published in French though potions of it are translated in this book.
The scent industry is a multi billion dollar industry controlled by seven companies. They are all very competitive and secretive about their formulas. Of course the big money is in manufacturing scents by the ton for things like hand soap or laundry detergent. Here the object is to make a good smell cheaply.
At the top of the pyramid are the fashion houses. These people write “briefs” to the scent companies which are verbal descriptions of their new ideas for perfumes. A hit perfume can mean millions in high margin profits until someone makes a knockoff of the scent. Patenting a new scent is a huge financial win.
At first the scent houses were delighted to get the famous Luca Turin working for them, but Luca couldn’t keep his mouth shut. When the fashion press asked him what he thought of some new perfume, if he didn’t like the scent he would say so in precise, accurate and devastating terms. This got him fired.
Even if he couldn’t be employed in the “creative” side of the perfume industry, Turin hoped his new theory could be put to use in the chemical side of the industry. The scent companies have large databases of chemical compounds that have been verbally described by professionals who have smelled and categorized the compounds. Turin believed that he could make a computer program that could predict what a molecule would smell like if he could get hold of these databases that are kept secret by each scent company.
The problem with this approach was that if it worked, it would mean firing most of the chemists who worked for the scent companies. Chemists have no way of knowing what compounds will smell like when they synthesize them. Today they synthesize compounds at random that are “similar” to compounds that have the desired characteristics, but this has turned out to be terribly expensive as most compounds smell the same as existing ones or don’t have the desired characteristics.
At the time the book was written, Luca Turin was unable to convince any of the scent houses to allow him to access their top secret databases to try out his theory; however, today he is employed in the United States by one of the scent houses.
Luca Turin certainly is great fun to read about if just for his passion about life, science, beauty and art. He is a hero to those of us who value individualism over conformity. I don’t know whether Turin’s theories are correct or not. I suspect they are, but I’m very familiar with technologists stubbornly ignoring the obvious. I have worked as a computer programmer for many years and run up against pointy haired managers who still haven’t gotten the message about the importance of the internet.
Turin’s nearly complete rejection by the scientific establishment and the scent industry is more the norm than we’d like to imagine. The Emperor of Scent doesn’t have any answers, but perhaps telling Turin’s story is good enough. The story is far from over.
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