conclude this section, let us mention briefly three supplementary concepts or practices for the defensive investor. The first is the purchase of the shares of well-established investment funds as an alternative to creating his own common-stock portfolio. He might also utilize one of the "common trust funds," or "commingled funds," operated by trust companies and banks in many states; or, if his funds are substantial, use the services of a recognized investment-counsel firm. This will give him professional administration of his investment program along standard lines. The third is the device of "dollar-cost averaging," which means simply that the practitioner invests in common stocks the same number of dollars each month or each quarter. In this way he buys more shares when the market is low than when it is high, and he is likely to end up with a satisfactory overall price for all his holdings.