Abdul-Lateef sits in the shade at the front of his shop, a glint in his eye and a week's growth of beard on his cheeks. With care, he weighs out half a dozen dried chameleons, wraps them in a twist of newspaper, and passes the packet to a young woman dressed in black.
"She will give birth to a handsome boy child," says the shopkeeper when the woman has gone.
"Are you sure?"
Abdul-Lateef stashes the money into a pouch under his shirt. He scans the assortment of wares - mysterious pink powders, snake skins, live turtles, bundles of aromatic bark, and he smiles.
"We have been helping women like her for five centuries," he says slowly, "And never has a customer come to complain. Believe me, I speak the truth."
Walk through the bustle of Fes's medina and it's impossible not to be catapulted back in time. It is as if the old city is on a frequency of its own, set apart from the frenzied world of internet and iPods and all the techno clutter that fills our daily lives. Abdul-Lateef and his magic-medicinal stall are a fragment of a healing system that stretches back through centuries, to a time when Fes was itself at the cutting edge of science, linked by the pilgrimage routes to Cairo, Damascus and Samarkand.
These days the low-cost airlines shuttle the curious back and forth to Europe. And everyone they bring is tantalised by what they find. Fes is the only medieval Arab city that's still absolutely intact. It's as if a shroud has covered it for centuries, the corner now lifted a little so we can peek in.
Once the capital of Morocco, Fes is one of those rare destinations that's bigger than mass tourism, a city that's so self-assured, so grounded in its own identity, that it hardly seems to care whether the tourists come or not. Moroccans will tell you that it's the dark heart of their kingdom, that its medina has a kind of sacred soul.
Wander the labyrinth of narrow streets and you can feel it. It's all around you - in the meat bazaar, where shanks of mutton nestle on fragrant beds of mint, and it's down in the most ancient quarter, at er-Rsif, where the seed of Fes fell more than a thousand years ago. But perhaps the spirit is felt strongest of all at the ancient leather tanneries, whose dying pits have endured since the days of Harun al-Rachid.
Stroll through the medina and you're never far from the sound of a craftsman beating a pattern into a sheet of burnished brass, or the hum of a homemade loom, or a lathe shaping a piece of scented argan wood. The slender sidestreets are packed with hundreds of one-room workshops where master craftsmen toil from morning to night, as their ancestors have done since antiquity.
Their wares fill the little tourist shops on Tala'a Kabira, the medina's main thoroughfare. Unlike Marrakech, with its sprawling tourist emporia, there's an innocence about searching for a bargain in Fes. Many of the shops aren't geared to tourists at all. There are just as many outlets selling bath plugs, bras and sewing thread to the locals as there are those offering embroidered yellow slippers, kaftans and heavy metal castanets to the waves of tourists who flock through.
Despite the giddying array of crafts manufactured by hand in the medina, Fes is about much more than the tourist objects for sale. Even the quickest visit gives you a sense of the city's extraordinary cultural and intellectual heritage and helps to remind all who come of the achievements of the Islamic faith.
The centrepiece of this is surely the Al-Karaouine university and its mosque (founded in 859 AD), regarded as the oldest continuously-used centre of learning on earth (so says the Guinness Book of Records).
Al-Karaouine is just one of dozens of medieval madrasas, religious schools, found in Fes. Thankfully, a number of these are now being restored, some of them with grants from Unesco. One of the most refined of all is the Bou Inania madrasa, which boasts fabulous mosaics, geometric cupolas crafted from cedarwood, and tiles carved with couplets from the Qur'an.
Across the street from it stands the remains of Fes's once-grand medieval water clock, now ruined. And tucked away behind it, to the left of a fishmonger's stall, is the tiny jewel, Cafe Clock. Although only open for a year or so, "The Clock", as it's become known, is already an institution, a confluence where visitors, expatriates and local Moroccans meet. It's laid out on numerous levels, its terraces commanding views over the city.
The Clock came from the imagination of an indefatigable Englishman, Mike Richardson, for whom Fes was love at first sight. The outstanding food hints at Mike's background in catering - he was a maitre d' at The Wolseley and, before that, at The Ivy in London.
Poised on the menu between Caesar salad and cheesecake are the words "camel burger". Mike pushes back his mop of ginger hair and exclaims: "I searched for years for the perfect meat for burgers, and I found it here in Fes. Camel meat's got the ideal consistency and succulence, and it sits so nicely on the bun."
The burgers are by far The Clock's best-seller, so much so that Mike spends much of his time trawling the bazaars in search of fresh camel meat and the other ingredients needed for his secret recipe. But his cafe is about much more than slaking hunger pains. He feels a responsibility to highlight a little of the heritage for which Fes is so renowned.
In the last handful of years, quite a number of foreigners have dropped everything and moved to Fes. Most of them, like Mike, have been attracted by the gravity of the place, the kind of serenity that's absent in other more care-free tourist hotspots. You get the feeling that they can't quite believe their luck at having the chance to be living in such a magical destination.
Lured by the prices and availability, many have bought courtyard homes in the medina and set about the painstaking restorations. Some of these have been transformed into small maisons d'hotes, sometimes with no more than three or four rooms.
One of the great joys of Fes is the feeling that it's worn in and loved, appreciated equally by visitors as by those whose families have lived there for centuries. If there's a downside, it's that a great number of the buildings are in need of repair in varying degrees. The climate is largely to blame - blazing hot in summer, freezing in winter.
Unesco regards Fes as a world heritage centre and has supported the city, quite literally. Under its initiative, thousands of wooden staves have been put up to keep those buildings most in danger from falling down. Others are working to help in a more modest way.
The American-born director of the city's Arab Language Centre, David Amster, has lived in the Fes medina for more than a decade. Passionate that any renovation be completed to the same exacting standards achieved by the original craftsmen, he ploughs anything he can spare into renovating public streets of his neighbourhood that are falling into disrepair.
Back on Tala'a Kabira, the medina's main street, Abdul-Lateef is crushing a mortar half-filled with dried damask roses. He coaxes his little son, Mustapha, to pay attention; after all, the boy will inherit the shop just as his father did.
An American tourist pauses to photograph the front of the shop, before his wife reels over and barks for him to hurry up and get back to the group. When they have gone, Abdul-Lateef wipes a hand over his brow.
"If that man had time to spare I could give him some of this," he says, holding up the potion he's mixing. "It's a special preparation that would make his wife beautiful again."
NOTE: In Arabian Nights by Tahir Shah is published by Doubleday