One thing Ellena viewed with a decidedly jaundiced eye was the the American obsession with synthetic musk molecules. These had a rather strange olfactory backstory.

Musk - real musk - is a molecule: (3R)-methylcyclopentadecanone, but its popular name is muscone. (The chemical name/common name pairing is quite common; there is, for example, the molecule z-acetoxybenzoic acid which also has a popular name: aspirin.) Muscone is found, at a concentration between 0.5 percent and 2 percent, in something called Tonquin musk, a richly stinking secretion mixing hundreds of molecules that comes from a gland inside the male musk deer. Extract the rich secretion, separate out the little bit of muscone from it, and by itself this one molecule has the warm, sensual, rich scent of clean warm skin. It's only this molecule (not the full, richly stinking, animalic Tonquin musk secretion) that perfumers call the scent of musk.

The problem was that you had to kill the musk deer to get its gland. This made it harder to find (it also became increasingly illegal for ecological reasons)' What to do. In 1888 a man named Allert Bauer was searching for new explosives and noticed that when you did a chemical reaction with TNT (trinitrotoluene) and tertbutyl halides, the two produced a new synthetic molecule that smelled almost exactly like (3R)-methylcyclopentadecanone-i.e., like musk. The molecule, found via this explosive that had nitros in it and itself containing a nitro group, was called a nitro-musk. Named Musk Bauer, it became the first synthetic musk used in perfumery, the replacement for the natural material.

Chemists then found other synthetic musks: Musk Ketone was created in 1894 - a lot was put into Chanel No.5, Brut, and many more perfumes - and Musk Xylol, Musk Tibetene, Musk Ambrette, and Moskene. The problem with the nitro-musks is that they had NO2 groups that were unstable and degraded into different colored products. (Also some turned out to be toxic and were banned.) So the industry set out to find replacements for the replacements, and they found the polycyclic musks. These-Galaxolide was a famous one-had no NO groups. But the polycyclics, it turned out, didn't biodegrade, so they went back and looked around in the natural musks (called macrocyclics) and modified them to come up with new synthetic musks like Habanolide and Musk R1. And then the linear musks, like Helvetolide and Serenolide, which were cheaper and had all the advantages of macrocyclics, plus in some cases also slightly fruity twists.

The strange thing was, says Ellena, what Americans used them for. Essentially these molecules were used as perfumes for laundry detergents. "The first scented detergents arrived in France from the U.S.," said Ellena, "where they existed since before the war:' He listed them: Colgate, Procter, Unilever. 'They created these molecules in a lab and smelled them, and they smelled strong, and they were quite stable. They were also cheap to manufacture. They weren't water soluble. And these molecules smelled good in quote marks, which is to say people like them, which is certainly one definition of good. So how to use them? They found out that when they put them in detergent they stuck very well to fabric during the wash-again, water insoluble - so they put lots of them in cleaning products and put these products on the market. What happened? People associated this smell in their detergent with the idea of "clean." The molecules rubbed off from their clothes to their skin, and then people become used to having these molecules on their skin, so they came to associate wearing these synthetic molecules with smelling of fresh laundry, and so today when people smell these synthetics they say, 'Clean' and they say, 'Skin' and they say, 'It smells of Me" He added with a smile, "All of this unconsciously, of course.'

(It keeps perfumers on their toes. You have, for example, a truly first-rate scent by l' Artisan Parfumeur, Mure et Musc- Blackberries and Musk - one of the more wonderful perfumes around, expertly crafted, and it uses these synthetic musks, which means that if the perfumer doesn't dose them right, it could smell a little bit like Tide because it smells like the musk 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-gamma-2-benzopyran, which is sold under the trade name Galaxolide, i.e., the smell of laundry detergent. So you need to be careful.)

Ellena evinces disdain for certain materials, but it is never a prejudice against a category and it is never for ideological reasons. It is always an aesthetic choice. "In the 1990S, I created Declaration for Cartier," he says, "and I used synthetic musks. Today I don't use synthetic musks, not because I think they smell bad-I don't-but because I think they're easy. They're a crutch. When you don't know how to sweeten something, you put in sugar syrup. It's very easy. But I use them when I want them." He names Angeliques sous la pluie, a gorgeous floral perfume he did for Frederic Malle's collection. "Sugar is easy to use:' he says and makes a dismissive motion: "Sugar for sugar's sake: no." Ellena loathes dihydromyrcenol as much as I do. It's a molecule that smells like sink cleanser spilled on an aluminum counter. (Actually I've met few perfumers who don't dislike it-''I'm at war with this molecule!" one of them e-mailed me when I brought it up with him-though often not be- cause of the way it smells but simply because aesthetically it has become a huge eye-roll of a cliche.) Ellena identifies it (not enthu- siastically) as opening what he calls " perfume's phase hygienique." (He simply noted, "Dihydromyrcenol was hugely used to scent laundry detergents," and stopped there.) To Ellena, you could pinpoint the beginning of the hygienic trend as Paco Rabanne Pour Homme (1973), which was leading away from leathers and ferns and spices and straight into the fluorescent-lit drugstore detergent aisle, but the di-hydromyrcenol revolution was formally launched in 1982 by Pierre Wargnye, who exploded it onto the scene by-ingeniously at the time-making it a jaw-dropping 10 percent of the formula of Drakkar Nair. There'd never been anything like it, and frankly it was kind of sexy to smell like your shirts just out of the dryer.