This theory of crime received a severe shock in the “forties” from the investigations of Dorothea L. Dix and others, who showed the great prevalence of insanity and idiocy among the delinquent classes. It could scarcely be denied even by the traditional jurists that the exercise of free will was likely to be seriously impeded by insanity or feeble-mindedness. From 1850 to the beginning of the present century the most notable advances toward a more intelligent conception of crime and its treatment consisted in the gradual but definite triumph of the notion of detention and punishment as agencies for reformation rather than as instruments of social revenge. For more than a century of its history the penal, reformatory and correctional institutions of Pennsylvania were limited to the county jails and the few and scattered workhouses, which were erected mainly in conjunction with the almshouses. In the jails there could be no approach to anything like a differentiated treatment of delinquents. In them were herded promiscuously those imprisoned for debt, those convicted of crime and those accused or held as witnesses; those of all ages and both sexes; those convicted of all categories and grades of crime punishable by imprisonment; those of all mental states--normal, feeble-minded, neurotic, psychotic, epileptic. The few colonial workhouses were employed as little more than an agency for suppressing vagrancy. The first step in a differentiated treatment of crime and criminals came with the erection of a semi-state prison in the Walnut Street Jail in 1789-90. This provided for a partial differentiation between those convicted of the more serious crimes and those convicted of petty offenses or awaiting trial. It did not however, attempt any scientific differentiation on the basis of age, sex or mental state. Children and adults, male and female, sane and insane, were confined in contiguity. The opening of the State penitentiaries at Allegheny and Philadelphia in 1826 and 1829, with their fundamental principle of solitary confinement, carried further the process of differentiation, but still continued to apply the same general type of treatment to all incarcerated inmates. It was a system of separation rather than of a differentiated treatment of special types of prisoners.