In the good branch of the Kallikak family there were no criminals. There were not many in the other side, but there were some, and, had their environment been different, no one who is familiar with feeble-minded persons, their characteristics and tendencies, would doubt that a large percentage of them might have become criminal. Lombroso’s famous criminal types, in so far as they were types, may have been types of feeble-mindedness on which criminality was grafted by the circumstances of their environment. Such facts as those revealed by the Kallikak family drive us almost irresistibly to the conclusion that before we can settle our problems of criminality and pauperism and all the rest of the social problems that are taxing our time and money, the first and fundamental step should be to decide upon the mental capacity of the persons who make up these groups. We must separate, as sharply as possible, those persons who are weak-minded, and therefore irresponsible, from intelligent criminals. Both our method of treatment and our attitude towards crime will be changed when we discover what part of this delinquency is due to irresponsibility. If the Jukes family were of normal intelligence, a change of environment would have worked wonders and would have saved society from the horrible blot. But if they were feeble-minded, then no amount of good environment could have made them anything else than feeble-minded. Schools and colleges were not for them, rather a segregation which would have prevented them from falling into evil and from procreating their kind, so avoiding the transmitting of their defects and delinquencies to succeeding generations. Thus where the Jukes-Edwards comparison is weak and the argument inconclusive, the twofold Kallikak family is strong and the argument convincing. Environment does indeed receive some support from three cases in our chart. On Chart II, two children of Martin Jr. and Rhoda were normal, while all the rest were feeble-minded. It is true that here one parent was normal, and we have the right to expect some normal children. At the same time, these were the two children that were adopted into good families and brought up under good surroundings. They proved to be normal and their descendants normal. Again, on Chart IX-a, we have one child of two feeble-minded parents who proves to be normal--the only one among the children. This child was also taken into a good family and brought up carefully. Another sister (Chart IX-b) was also taken into a good family and, while not determined, yet “showed none of the traits that are usually indicative of feeble-mindedness.” It may be claimed that environment is responsible for this good result. It is certainly significant that the only children in these families that were normal, or at least better than the rest, were brought up in good families.