Stock prices fell across Europe and Asia on Friday morning, extending a stock-market slide that sent the Dow down 268 points, or 2.6 percent, on Wall Street Thursday. Recent stock-market woes have more to do with Europe's limping economy than America's own slow recovery. Financial crises in European countries like Greece and Portugal, which use the euro, have some frightened that the EU's currency could rapidly lose its value and affect growth worldwide as a result. “The question now is, how big is this fire going to be?” Uri D. Landesman, head of global growth at ING, told The New York Times. “What is panic, and what is legitimate? We don’t know at this point.” Some are hoping that richer European countries, like France, England, and Germany, might bail out their weaker neighbors in order to stabilize the situation.