ONE DAY the mayor of an East Coast city calls in a top aide and asks: "What do we do with the old slaughterhouse now that the sausage company's left town."

"Well," says the aide, "I assume we turn it into shops, theaters and restaurants."

"Of course," says the mayor. "Just like the old rendering plant and the old sawmill."

In six months the place is opened as a complex of shops, theaters and restaurants called The Abattoir, and thousands of people go there who wouldn't be caught dead in a slaughterhouse or a suburban mall.

After that the mayor doesn't have to call on his aides anymore. When the question comes up of what is to be done with the old trestle bridge, the old waterworks or any other depressing old structure, he gets on the phone with the bankers, and together they say: "Shops, theaters and restaurants!"

One morning the mayor's secretary bursts into his office: "The people down at The Old Concrete Sewer Pipe Factory say four new cookie shops have appeared there in the last 24 hours and two more are sprouting. They're displacing all the other shops -- also the theaters and restaurants."

In fact, it soon becomes apparent that this is happening all up and down the East Coast, wherever cities have converted old steambaths, stables, railroad roundhouses, fish-packing plants, shipyards, smokestacks, shantytowns and the sheltered areas under highway bridges into shops, theaters and restaurants. All are discovering that the next stage is that everything turns into cookie shops.

A group of mayors assembles in Newark, which had been converted into a convention center, and a professor of urban entropy from Harvard explains the phenomenon:

"When you fill up grimy old structures that once served a useful purpose with shops, theaters and restaurants, they tend to become absurdly overspecialized -- like four stores each selling a different color of pasta, or a restaurant that serves only zucchini. These places are susceptible to being swept away by the slightest change in consumer taste, and when that happens the cookie shops, being rather hardy, move in and take over."

The end result, of course, is a chocolate chip cookie extending roughly from North Carolina to New England and from the Appalachians to the Atlantic. Don't say you weren't warned.