=Social Dangers in Vasectomy.--=It has been urged against vasectomy that it will work untold harm because it relieves of the responsibility of a probable parentage. This argument does not appeal to one as very weighty as far as the imbecile or other degenerate is concerned, because one of the very traits characteristic of such individuals is lack of any sense of responsibility. By this same token, however, we have a very good argument for sequestration as against sterilization, for the degenerate, even though sterilized, will not be restrained sexually and will be likely to disseminate venereal diseases or commit rape. Furthermore, there will be the temptation to sterilize and liberate certain types that would otherwise have been kept permanently in custody. =Our Present Knowledge Insufficient.--=When all is said and done, after we take into account the meagerness of our present knowledge on the subject, it is not to be wondered at that many thoughtful students of a conservative turn of mind, feel that any considerable practise of sterilization is premature. The problem has so many phases, and despite occasional bits of positive knowledge, we are yet in such a sea of ignorance regarding it, that in no field is the good Friar Laurence's admonition of "wisely and slow; they stumble that run fast," needed more at present than it is here. There is little doubt that in theory the feeble-minded and similar defectives should be sent to institutions and kept there, but the important practical question is, can this be done? We can have no final answer until it is tried. While the initial expense would undoubtedly be great, if we could keep our defectives from propagation for a single generation we could very materially lessen their numbers and in succeeding generations the expenses of their care would rapidly diminish. The one crying need that stands out most prominently in this whole field is that of careful investigation of individual cases and specific types of malady, together with an accurate census of conditions as a whole. Our knowledge of individual malign heredities is too meager to carry us very far at present. When we have found after adequate investigation in just which specific types of defects heredity is an important factor--and we shall undoubtedly find it to be one in many cases--then we can proceed confidently with sterilization, if it will prove to be more practical and desirable than sequestration.