Not that I expect you to revise that, but anyway, here are two post you could read about it.

Naked Capitalism: Banks are not reserve constrained

Some people still believe in the money multiplier taught in old economic textbooks that fractional reserve banking has banks taking deposits, multiplying them as much as possible, subject to the reserve ratio, and making a much larger amount loans. That is not how it works. In practice, banks don't wait for the reserves to be available to issue loans. They make loans first and then borrow the reserves in the interbank market. The loans come first, not the reserves.

Banks are never constrained by reserves or reserve ratios. Banks are capital constrained. In our fiat money system, the central bank uses reserves in the system to help the it hit a target interest rate. So, the central bank provides the system with enough reserves to meet any reserve ratio at its target rate. The reserves are about helping set interest rates, not about pyramiding money on a reserve base.

Understanding this should also help you understand why QE has been a boon for financial speculation but a bust in the real economy:

Lest it be said that I'm parodying neoclassical economics, or relying on what lesser lights believe when the leaders of the profession know better, here are two apposite quotes from Ben Bernanke and Paul Krugman.

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They are profoundly wrong on this point because neoclassical economists do not understand how money is created by the private banking system--despite decades of empirical research to the contrary, they continue to cling to the textbook vision of banks as mere intermediaries between savers and borrowers.

This is bizarre, since as long as 4 decades ago, the actual situation was put very simply by the then Senior Vice President, Federal Reserve Bank of New York, Alan Holmes. Holmes explained why the then faddish Monetarist policy of controlling inflation by controlling the growth of Base Money had failed, saying that it suffered from "a naive assumption" that:

the banking system only expands loans after the [Federal Reserve] System (or market factors) have put reserves in the banking system. In the real world, banks extend credit, creating deposits in the process, and look for the reserves later. The question then becomes one of whether and how the Federal Reserve will accommodate the demand for reserves. In the very short run, the Federal Reserve has little or no choice about accommodating that demand; over time, its influence can obviously be felt. (Alan R. Holmes, 1969, p. 73; emphasis added)

The empirical fact that "loans create deposits" means that the change in the level of private debt is matched by a change in the level of money, which boosts aggregate demand. The level of private debt therefore cannot be ignored--and the fact that neoclassical economists did ignore it (and, with the likes of Greenspan running the Fed, actively promoted its growth) is why this is no "garden variety" downturn.