Top-end restaurants like Delmonico's in New York sold oysters to wealthy patrons like Diamond Jim Brady (he liked at least three dozen before dinner). And outdoor oyster counters on New York's Canal Street sold poor folks all the oysters they could eat for six cents.

Americans got their oyster-eating traditions from the British, who in turn learned about oysters from the ancient Romans, who believed British oysters to be the finest in the world. And in fact, there was a good reason why the oysters got better as the Romans ventured farther north. In cold water, oysters "fatten up" to protect themselves. But instead of fat, they lay down a sugar compound called glycogen. The colder the water, the more of this sugarcoating they produce. That's why, even here in Texas, oysters taste best during the coldest part of the winter.

By the late 1700s, the once seemingly endless supply of oysters in Europe began to dwindle, and they became more expensive. The principles of oyster cultivation, which had been developed by the Greeks, spread throughout the empire to increase the oyster harvest.

The French system of oyster cultivation is the most sophisticated in the world. Oysters are bred on frames in one part of the sea and matured for several years in government-owned "oyster parks" along the coast. The oysters, called claires, are then fattened in tidal pools. But while French oysters may be the world's best, they're so expensive that they've become a rich man's treat.

The European gourmet oyster culture is now taking over in the United States. In the early 1980s, marine-biologist-turned-fish-monger Bill Marinelli popularized the tiny Kumamoto oysters, which were imported from Japan and grown in California's Humboldt Bay, by selling them to cutting-edge Berkeley restaurants like Chez Panisse, Fourth Street Grill and Zuni Café.

Unfortunately, some overzealous cultivated-oyster salesmen go overboard in trying to justify the high price of their product by belittling America's native oysters and the long culinary tradition they represent.

There's no doubt that expensive gourmet oysters are the wave of the future. Oregon, Washington and Massachusetts, along with Vancouver, Nova Scotia and Prince Edward Island in Canada, are all producing delicious farm-raised oysters these days. And contrary to the San Franciscan's protests, it's easy enough to find pricey cultivated oysters in Houston.

One night, I asked the lady from Cleveland and a Texas oyster lover to join me in an oyster tasting. We started in the funky turquoise and navy dining room of Joyce's Seafood and Steaks, where we polished off three-dozen Gulf oysters and a bottle of New Zealand Sauvignon Blanc.

Then we headed over to the tony environs of McCormick & Schmick's, where we were shown to a white linen-covered table. "We're just here to eat oysters," we told the waiter.

"We have Houston's best oysters," the waiter said.

They had 12 varieties of cultivated oysters available. So we got two dozen -- three each of eight different kinds -- and a bottle of French Muscadet. The standouts were the Malpeque oysters from Prince Edward Island, which were extremely salty with a strong fish flavor that harmonized beautifully with the lemony Muscadet. The tiny Kumamoto oysters were delectable, but they were so small you could barely tell you had anything in your mouth. We also sampled salty Imperial Eagle oysters from Vancouver, Fanny Bay oysters and several others.

"The difference between some of these is pretty subtle," I observed.

"With an accent on the 'b' in subtle," the Texas oyster lover said. When we'd finished the oysters and wine, he insisted on a nightcap at Willie G's, a seafood restaurant nearby. There we polished off another two dozen big, fat, watery Gulf oysters. I ate mine with a glass of Fat Tire beer.

"So what's your verdict?" I asked my fellow oyster lovers.

We all had to agree that the cultivated oysters really have more concentrated flavors than Gulf oysters. But a dozen tiny oysters at McCormick & Schmick's sell for $21.65. A dozen fat Gulf oysters at Joyce's go for $6.95.

"I have to admit, quantity does count," the lady from Cleveland said. "It's one thing to eat oysters as a delicacy, but it's another thing to chow down on them."

"I think there's gourmet oyster eaters and then there's oyster eaters," said the Texan.

The notion that oysters are an aphrodisiac seems rather quaint to modern minds. But then again, we don't eat oysters like they used to. Casanova had 50 with his nightcap every evening, and his libido was legendary.