To drive home his point, lawyer Jeffrey B. Golden raised a toilet plunger as an illustration of how American bankers feel about Europe veering toward a common currency.

"The concerns are primarily about the plumbing," said Mr. Golden, a partner in the firm of Allen & Overy. In other words, the European Union's plans for adopting a single currency called the euro by 1999 may look good, but beware of leaks.

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