Science Forums 2

[Michaelangelica]

More about Turin's book here
http://www.nytimes.com/2006/12/03/bo...c50L7ewnSdy3DA

Luca Turin’s engaging new book follows this form, but doesn’t feel at all like something we’ve read before — which is a tribute both to its subject and to its author. “The Secret of Scent” is about one of the great mysteries in science, one that is not just under our noses (like all the best mysteries), but actually inside the nose. That mystery is smell, and specifically the way the brain interprets molecules as smells. No two molecules, however similar their chemical structure, smell identical. Why not? As Turin asks, “What is this chemical alphabet that our noses read so effortlessly from birth?”

Science thinks that it has answered this question, and that the answer has to do with the shape of a molecule: the geometric arrangement of its atoms determines its smell. Turin disagrees.. . .

Turin has an extraordinary gift for writing about smell. Before he became interested in the science of smell, he was that rare thing, a brilliantly readable perfume critic. He is a biologist by training, based in London after a peripatetic career that eventually led him to the business of fragrance chemistry. He first fell in love with perfume while working in France, via an encounter with a Japanese perfume called Nombre Noir: “halfway between a rose and a violet, but without a trace of the sweetness of either, set instead against an austere, almost saintly background of cigar-box cedar notes. At the same time, it wasn’t dry, and seemed to be glistening with a liquid freshness that made its deep colors glow like a stained-glass window.”

Blimey. There is no unpretentious way of writing about smell;

http://www.nytimes.com/2006/12/03/bo...c50L7ewnSdy3DA

Turin thinks our sense of a molecule’s smell, rather than being based on its shape, comes from its wave vibration. This theory has been around for a number of decades but has suffered from the lack of a plausible mechanism by which it might work. Turin’s suggested mechanism is based on a quantum phenomenon known as “inelastic electron tunneling,” and it is no easier to understand than its name. The nose has (this was discovered in 1991) 347 scent receptors; these, he thinks, function as a spectroscope, each of them responding to a specific frequency of molecule, and translating them into what we perceive as a smell.