On Thursday Jean-Claude Trichet, the president of the European Central Bank or E.C.B. — Europe’s equivalent to Ben Bernanke — lost his sang-froid. In response to a question about whether the E.C.B. is becoming a “bad bank” thanks to its purchases of troubled nations’ debt, Mr. Trichet, his voice rising, insisted that his institution has performed “impeccably, impeccably!” as a guardian of price st