“The high grade imbecile, frequently known as the moron, is one who can do fairly complicated work without supervision, but who cannot plan, who lacks ordinary prudence, who cannot resist the temptations that are common to humanity. The high grade imbecile is most dangerous because, except to the expert, he is apparently not feeble-minded and is, therefore, usually treated as normal, and permitted to multiply his kind, and to corrupt the community.” This description would tend to include cases above our isolation group. Besides the questionnaire the commission made an intensive study of 52 towns in which it says practically complete census returns were obtained by consulting doctors, school and town officials. With these supplementary cases it secured a list of 2,019 cases outside of institutions, making a total of 2,966 recorded cases within the state or 0.69% of the population. When it estimated the proportion for the entire state on the basis of the rate of canvass returns to questionnaire returns, this proportion rose to 0.95%. The commission does not advocate compulsory isolation for all of these people although it recommends custodial care for the feeble-minded women and girls of child-bearing age, apparently of the degree of deficiency represented by its criteria. This enumeration of 0.69% of the people of a state as feeble-minded is the most liberal general census of the feeble-minded in any large area. It clearly shows the trend of diagnosis since the British Census. The Extension Department of the Training School at Vineland, N. J., states regarding estimates of the number of feeble-minded in the general population: “Conservative estimates give one in three hundred as the probable present number.” Under the discussion of estimates of the general population I have already cited Goddard's estimate which was approximately 0.3 to 0.4% and the enumeration of 0.4% by the British Royal Commission in 16 districts with over two million population. While all of these estimators are speaking broadly of the feeble-minded, in the general population, we shall not be far wrong in supposing that they are considering mainly those deficients for whom the state might well expect to provide care for life, isolating all those who cannot be eugenically guarded at home. We shall later quote the estimate of Van Sickle, Witmer and Ayres of 0.5% of the school population as “institution cases.” Our estimate of 0.5% in the group justifying isolation on the ground of intellectual deficiency seems to be conservative and to harmonize fairly this type of estimate.