By Thursday, the drumbeat of worries over Bear had grown so loud that my voice mail box was full of gleeful short sellers and panicked investors. The talk built up that evening, as Bear went hat in hand to the Federal Reserve because the firm had run out of money. By Friday, even with the Federal Reserve’s rescue effort by way of JPMorgan in full swing, Bear’s stock fell to $30 a share. People forget that Wall Street is a fragile machine. Cash, or “liquidity,” as it is known in the trade, is the oxygen that keeps investment banks alive. No matter how healthy you are, you can’t breathe if someone puts a pillow over your head. That’s what Bear Stearns’s clients and rivals did, and they did it without remorse.