快猫短视频

TIRED, scratched and soaked with sweat, the hunters begin to think about
turning back. They鈥檝e slogged up and down the steep paths of this Madagascan
forest since dawn. Time is running out. Dusk is falling and they still haven鈥檛
caught sight of their quarry. Suddenly they stop. One of the men lifts his head
and sniffs. He knows they are close. He scans the undergrowth in the deepening
gloom鈥攁nd suddenly he spots what they鈥檝e been looking for. There, hidden
beneath some leaves at nose height is a tiny spike of flowers, the whole bunch
no bigger than a thumbnail. Within minutes, the hunters have set their trap. All
they have to do now is wait.

The hard slog was worth it. Next morning, there in the trap is a rare
catch鈥攁 new sort of smell. For the men in the Madagascan forest are
perfume hunters. And instead of rifles they are armed with nothing more sinister
than a few glass jars, a couple of pumps and some silicone tubing as they search
for new and exciting fragrances to make our lives smell sweeter.

Ever since the first unguentarii plied their trade in Roman Capua,
perfumers have had to keep abreast of changing fashions. These days they have
several thousand ingredients to choose from when creating new scents, but there
is always demand for new combinations. The bigger the 鈥減alette鈥� of smells, the
better the perfumer鈥檚 chance of creating something fresh and appealing. Even
with everyday products such as shampoo and soap, kitchen cleaners and washing
powders, consumers are becoming increasingly fussy. Cheap, synthetic-smelling
pongs are out. Fresh and natural smells are in. And many of today鈥檚 fragrances
have to survive tougher treatment than ever before, resisting the destructive
power of bleach or a high-temperature wash cycle.

Chemists can create new smells from synthetic molecules, and a growing number
of the odours on the perfumer鈥檚 palette are artificial. But nature has been in
the business far longer. Plants produce countless fragrant chemicals. Some are
intended to attract pollinators. Others are produced for quite different
reasons. The fragrant resins that ooze from wounds in a tree, for instance,
defend it against infection.

Last October, Quest International, a company that develops fragrances for
everything from the most delicate perfumes to cleaning products, sent an
expedition to Madagascar in pursuit of some of nature鈥檚 most novel fragrances.
Madagascar is an evolutionary hot spot, and 85 per cent of the plants there are
found nowhere else. For Robin Clery, a natural products chemist based in Quest鈥檚
laboratories in Kent, and Claude Dir, the company鈥檚 head 鈥渘ose鈥� from Manhattan,
this meant exploring two contrasting landscapes in northern Madagascar. Their
first stop was a remnant of rainforest in the national park of Montagne d鈥橝mbre.
The second was the tiny uninhabited island of Nosy Hara off the north-west
coast.

With some simple technology borrowed from the pollution monitoring industry
and a fair amount of ingenuity, they bagged 20 promising new aromas. The
technology allows the team to gather fragrances as they waft from a flower or
leaf鈥攃apturing the mixture of volatile molecules that make up the smell
while leaving the plant itself undisturbed. But capturing the smell is just the
start of a long process. Back at the lab, Clery must identify the component
chemicals and then try to recreate the original odour from materials closer to
hand.

First, though, you must catch some likely new odours. In Montagne d鈥橝mbre,
Clery and Dir teamed up with guides from the national park authority (ANGAP) and
a local botanist. They were also joined by Felix Mayr-Harting from Quest鈥檚 Paris
office, whose job was to keep everyone鈥檚 noses focused on the sorts of smells
that might appeal to the company鈥檚 clients. The 鈥淎mber Mountain鈥�, 1500 metres at
its peak, is cloaked in moist forest and is home to a rich diversity of plant
species. 鈥淚t was like being a kid surrounded by candies,鈥� says Dir. As an
experienced 鈥渘ose鈥�, he has a finely tuned memory for smells and can distinguish
between thousands of different odours. 鈥淎nd here I was surrounded by unique new
aromas.鈥� Flowers may be the most obvious source of fragrance, but the perfume
hunters sniffed at everything. 鈥淲e were keen to look not just at flowers but
leaves, resins and woods鈥攅ven mosses,鈥� says Mayr-Harting.

Each day, the team packed their gear, pocketed some sandwiches and set out
from their hotel-cum-lab鈥攁 wooden hut lit by kerosene lamps, with cold
running water diverted from a waterfall just up the hill. They trailed up and
down paths and animal tracks, exploring the thick vegetation up to 10 metres
either side of the trail. Some smells came from obvious places, often big showy
flowers within easy reach. Others were harder to pin down. 鈥淥ften it was the
very small flowers that were most interesting,鈥� says Clery. Whenever the team
found something, it was up to Clery to figure out how to sample its smell.

Tape and string

With most flowers or fruits, the fragrance hunters used a technique
originally designed to trap and identify air pollutants. The technology itself
is relatively simple. A glass bell jar or flask is fitted over the flower. The
fragrance molecules are trapped in this 鈥渉eadspace鈥� and can then be extracted by
pumping the air out over a series of filters which absorb different types of
volatile molecules. The real challenge is getting the gear into place. 鈥淚n the
rainforest you have to be ingenious, and you usually need a lot of tape and
string to hold it all together,鈥� says Clery. Back in Kent, the molecules are
flushed out of the filters鈥攅ither with solvents or on a warm stream of
nitrogen gas鈥攁nd injected into a gas chromatograph for analysis.

If it鈥檚 impossible to attach the headspace gear, Clery fixes an absorbent
probe close to the source of the smell. The probe looks something like a
hypodermic syringe鈥攅xcept that the 鈥渘eedle鈥� is made of silicone rubber
which soaks up molecules from the air. Developed as a means of detecting organic
pollutants in water, the device is ideal for collecting scent molecules. 鈥淎ny
organic molecules floating around will stick to it,鈥� says Clery. 鈥淵ou might
catch a few stray molecules from other sources, but it gives you a chemical
snapshot of the fragrance.鈥� After a few hours, Clery retracts the rubber needle
and seals the tube, keeping the odour molecules inside until they can be
injected into the gas chromatograph in Kent.

The moist mountain forest is a far cry from the perfume houses of Paris or
Manhattan, but the sweat and insect bites paid dividends. Those tiny
Dichapetalum flowers discovered in the dusk had a peachy, coconutty scent.
Higher up the mountain, the hunters found an even fruitier fragrance. It came
from a green, golf-ball-sized fruit, very popular with the local lemurs. 鈥淭he
fruits didn鈥檛 have much smell at all when we picked them up,鈥� says Dir. 鈥淭hen we
cut into the skin.鈥� Out oozed a thick, white latex. 鈥淭he smell was almost
unnatural鈥攍ike something you get in the lab when you make a very
concentrated oil,鈥� says Dir. The fruits were from a large Chrysophyllum
tree, a relative of the sapodilla. And the smell? It was like some supercharged
pear. Analysis showed that the fragrance contains many of the same ingredients
as a pear鈥攂ut with a lot of extras. 鈥淚f it was just pear it wouldn鈥檛 be
very interesting because we know about pear already,鈥� says Dir. 鈥淏ut it was like
smelling the juice of hundreds of pears, with a nuance of pineapple, coconut and
a little floral note.鈥�

Some of the most promising fragrances were those given off by resins that
oozed from the bark of trees. Resins are the source of many traditional
perfumes, including frankincense and myrrh. 鈥淚f you see a resin, you smell it.
You don鈥檛 let one go past,鈥� says Clery. The most exciting resin came from a
Calophyllum tree, a relative of the Asian beauty leaf which produces a
strongly scented medicinal oil. The sap of this Calophyllum smelt rich
and aromatic鈥攁 little like church incense. But it also smelt of something
the fragrance industry has had to learn to live without鈥攃astoreum, a
substance extracted from the musk glands of beavers and once a key ingredient in
many perfumes. 鈥淲e don鈥檛 use animal products any longer, so to find a tree with
an animal smell is very precious,鈥� says Dir.

Before the odour-seekers left the forest there was one other fragrance they
were determined to capture. Montagne D鈥橝mbre is famous for its waterfalls. The
Grande Cascade drops some 80 metres from a green lake past lushly vegetated
cliffs. Like everything else in the forest, the falls have a distinctive smell.
鈥淵ou get a characteristic odour around waterfalls. It smells like a mix of
vegetation and minerals thrown off the rocks by the force of the water,鈥� says
Mayr-Harting. To a group of fragrance hunters, this was a new challenge. Could
they capture the essence of a waterfall?

The first problem was identifying what it was in the water that gave it such
a fresh, green fragrance. 鈥淭here鈥檚 no obvious source of odour鈥攏othing you
can see in the waterfall that gives it its smell,鈥� says Clery. The second
problem was how to collect the odour, capturing the smell from water rather than
air. Clery fixed up some of the silicone probes where they would be exposed to
fine spray from the falls. If they pick up organic pollutants from water then
they should also catch other sorts of organic molecules, including those
responsible for the odour of the falls. It worked. 鈥淲e have been able to
identify some of the odorous ingredients,鈥� says Clery. 鈥淲e found lots of
familiar materials, mainly from the more water-soluble bits from trees and
plants upstream, with resins, leaves, bark and moss from the plants growing
around the falls.鈥�

After the luxuriance of the rainforest, the little-known island of Nosy Hara
was a stark, dry place, geologically and biologically very different from the
mainland. This time, the team tagged along with a group of biologists from the
Universities of Oxford and Antananarivo who were studying Nosy Hara鈥檚 flora and
fauna. This craggy lump of limestone is only a few kilometres long, but the
interior rises up in massive weathered cliffs that are covered in thick, dry
scrub鈥攁 landscape known as 鈥渢singy鈥�. 鈥淎part from two beaches, the rest of
the island is impenetrable, except by hacking through the bush,鈥� says Clery.
Occasionally fishermen camp on the beaches while gathering sea cucumbers, but
they never venture inland.

The fishermen were responsible for the island鈥檚 most pervasive
smell鈥攖he stench of drying sea cucumbers. With everyone camping on the
same beach, it was hard to escape. 鈥淚t was an interesting olfactory experience,鈥�
says Mayr-Harting.

Away from the beachside pong, the fragrance hunters tracked down spicy barks
and leaves with a vague smell of eucalyptus. But the biggest prize was a
sweet-smelling sap weeping from the gnarled branches of some ancient shrubby
trees in the parched interior. So far, no one has been able to identify the
plant. Although the tree belongs to the same family as frankincense and myrrh,
the group suspects it might be a new species. The sap has a soft, sweet smell
reminiscent of those biblical perfumes but with added freshness and a hint of
juniper.

Sun-kissed seas

And if you think capturing the fragrance of a waterfall was a tall order,
Clery and his colleagues tried something even more ambitious on Nosy Hara. This
time they were after the scent of a coral reef. Odours that conjure up fresh,
clean lakes or sun-kissed seas are highly sought after by the industry. 鈥淔rom
the ocean the only thing we have is seaweed, and that smells dark and heavy. We
hope to find something unique among the corals,鈥� says Dir.

As with the waterfall, the hunters had to extract a smell from water rather
than air, although this time they did at least know the source of the molecules
they were after. This was an opportunity to try Clery鈥檚 鈥渁quaspace鈥�
apparatus鈥攂ell jars and pumps equipped with filters that work under water.
Early trials in the rock pools of Woolacombe on the north Devon coast had
produced a fragrance instantly recognisable as 鈥渆au de rock pool鈥� so Clery was
optimistic. On Nosy Hara, the jars were fixed over knobs of coral about 2 metres
down and water pumped out over the absorbent filters.

So what does coral smell like? 鈥淚t鈥檚 a bit like seafood. It鈥檚 a bit like
lobster and crab,鈥� says Clery. That isn鈥檛 enough to put Dir off. 鈥淭o me, there鈥檚
nothing that smells bad,鈥� he says. 鈥淏y diluting and combining with something
else you can create a quite different effect. It鈥檚 just a question of getting
the balance right.鈥�

The team鈥檚 task now is to recreate the best of their captured smells. First
they must identify the molecules that make up each fragrance. Some ingredients
may be common chemicals, and others easily synthesised. But some may be
completely novel, or they may be too complex or too expensive to make in the
lab. The challenge then is to conjure up the fragrance with more readily
available materials. 鈥淲e can create the smell with a different set of chemicals
from those in the original material,鈥� says Clery. 鈥淚f we get it right you can
sniff the sample and it transports you straight back to the moment you smelt it
in the rainforest.鈥�