We could not house, feed, and train even a million new chums each year—and a million wasn’t a drop on Terra; more babies than that were conceived every night. We could accept far more than would emigrate voluntarily but if they used forced emigration and flooded us. . . Luna has only one way to deal with a new chum: Either he makes not one fatal mistake, in personal behavior or in coping with environment that will bite without warning. . . or he winds up as fertilizer in tunnel farm.