Criminality, again, is associated with feeble-mindedness in the most intimate way. Not only do criminals tend to belong to large families, but the families that produce feeble-minded offspring also produce criminals, while a certain degree of feeble-mindedness is extremely common among criminals, and the most hopeless and typical, though fortunately rare, kind of criminal, frequently termed a "moral imbecile," is nothing more than a feeble-minded person whose defect is shown not so much in his intelligence as in his feelings and his conduct.
Sir H.B. Donkin, who speaks with authority on this matter, estimates that, though it is difficult to obtain the early history of the criminals who enter English prisons, about twenty per cent of them are of primarily defective mental capacity. This would
mean that every year some 35,000 feeble-minded persons are sent to English prisons as "criminals." The tendency of criminals to belong to the feeble-minded class is indeed every day becoming more clearly recognized.
At Pentonville, putting aside prisoners who were too mentally affected to be fit for prison discipline, eighteen per cent of the adult prisoners and forty per cent of the juvenile offenders were found to be feeble-minded.
This includes only those whose defect is fairly obvious, and is not the result of methodical investigation. It is certain that such methodical inquiry would reveal a very large proportion of cases of less obvious mental defect.
Thus the systematic examination of a number of delinquent children in an Industrial School showed that in seventy-five per cent cases they were defective as compared to normal children, and that their defectiveness was probably inborn.