A multiple loop for large inocula.

to large flasks. A large inoculum is important for the success of such transfers. The standard procedures for doing this, i.e., several loopfuls or pipetting, are not always the most desirable procedures. The former increases the possibility of contamination of both air and culture, and the latter requires additional time for washing and sterilization. We have, therefore, developed a multiple loop that serves our needs very well. The diagram indicates the steps in making it. Two, three, or four loops per wire can be used. For a triple loop, the wire is first bent over about four centimeters from the end, and wound around itself two or three times to form an elongated loop (figure 1). Then, using a pencil or other rounded object, individual loops are formed one at a time, one below the other, each held as formed by twisting the wire tightly once or twice. (It is only for clarity that these twists do not appear tight in the illustration.) Such a multiple loop is also useful in making serial dilutions, where one loopful is transferred from a first tube to a second, two loopfuls from the second to a third, and so on. We use separate inoculating loops, the first with one loop, another with two loops, etc. In practice this means only one actual transfer from tube to tube, greatly reducing the possibilities for contamination.