Of the kinds of mental unsoundness known to be inheritable which are of special significance from the standpoint of crime and delinquency undoubtedly feeble-mindedness ranks first. We have already seen that as our methods for detecting the higher grades of feeble-mindedness become more accurate we disclose in border-line cases a veritable hot-bed of mental incapacity suitable for the engendering of the criminal and the vicious. Here in addition to some of the more pronounced criminal types belong hosts of our chronic petty offenders, our sexually vicious and our "won't-works". One interesting outcome of a recent investigation into the army of unemployed in England was the discovery of the general unfitness of these unemployed. In our own country the habitually unemployed are so not because of lack of work, but largely because it is unprofitable to employ them. =The Bearing of Immigration on Crime and Delinquency.--=Perhaps in no field more than this of crime and delinquency, especially in so far as it is based on innate deficiency, does the gravity of the immigration question impress itself on us. How stupendous this problem[15] has become may be realized from the fact that according to the census of 1910, 13,345,545, or one out of seven of the inhabitants of the United States, were foreign born. And if we add to these the 18,897,837 of whom one or both parents were of foreign birth, we reach the astonishing total of over 32,000,000, or more than one-third of our total population, who are foreign born, or who have one or both parents of foreign birth. During the decade from 1900 to 1910, 8,500,000 foreigners came to the United States, of whom 5,250,000 remained to make a permanent home. This shows how rapidly our whole population might be radically changed. In recent years the source of our immigrants has shifted proportionately from northwestern Europe to southern and eastern Europe (Italy, Austria-Hungary and Russia), and whether for weal or woe this new blood must inevitably leave its impress upon us. Does it not behoove us then to seek with anxious eyes some knowledge of these invading hordes with whom we are to mingle our life-blood?