With the immediate campaign against delinquency centered against the propagation of the social deficients, we have the atmosphere cleared so that it is possible to turn attention to the best means of attaining this end. Sterilization, isolation, or guardianship, by force or by consent, which of these methods promises best? This is not a question for detailed discussion here. We may, however, call attention to the strides that have been made by such legislation as the British Mental Deficiency Act of 1913 and to the summary of the laws of the several states in our country published at the University of Washington, Seattle. The question whether sterilization is desirable must at present be settled apparently by the judgment whether the benefit in reducing the propagation of the unfit outweighs the danger to morality through the temptation of known sterility. The question of isolation of the sexes by either sterilization or segregation resolves itself into the question of accuracy of diagnosis and prognosis. Our review of the uncertainties of diagnosis should make us cautious. When we consider the social survival of many of those trained in the public school classes for deficients and when a dozen girls discharged from the Massachusetts institution for the feeble-minded succeeded in getting along in society (_164_, p. 49), it would seem wise to place the emphasis on first isolating those about whose danger to the community through delinquency or propagation of deficiency there would be the least question. This would mean those of uncertain mentality who were already repeated delinquents or in imminent danger and those who were of the lowest grades of deficiency, not the morons who were of uncertain moral and mental ability. Among the clearly deficient there is no question but that the emphasis should be to isolate first the girls and women of child-bearing age, since their chance of obtaining mates is greater than that of the deficient males. With doubtful cases public guardianship, such as that provided by the British Mental Deficiency Act of 1913, affords a promising remedy. Even those who are of uncertain ability should, when in danger, be provided with whatever protection guardianship can give. In this connection a suggestion of Dr. Goddard in the Survey, March 2, 1912, may be utilized. A court in returning an individual who is of uncertain ability to his family or guardian may well warn them: “We shall leave him in your custody, but we insist that you shall care for him, shall be responsible for him throughout his life, shall see that he does not get into mischief, and above all that he does not become a parent. Whenever the time comes that we find you are incapable of performing or are neglecting this duty, then we shall take him and place him in a colony.”