Along with this development of a properly differentiated system of treating the delinquent population, has gone the growth of specialized institutions for dealing with the closely related class of defectives, which was once treated indiscriminately along with the delinquent classes when its members were guilty of criminal action. The State institution for feeble-minded at Polk, opened in 1893, and at Spring City, provided by an act of 1903, and the State Village for Feeble-minded Women at Laurelton, not yet available for use, are designed to furnish scientific treatment for large numbers of those who would today be confined in the state prisons or county jails, if the ideas and institutions of 1840 prevailed. Even an institution for inebriates was contemplated in an act of 1913. But this vital and all important process of the differentiation, classification and specialized treatment of the delinquent and defective classes has now proceeded far beyond that most elementary stage of furnishing separate institutions for dealing with the most general classes of delinquents and defectives. It has been found that the terms defective, insane and criminal have only a legal significance and are practically useless when involving the problem of exact scientific analysis and treatment. Each general class of delinquent boys, of defective girls or of criminal adults, for instance, is made up of distinguishable and distinct types which demand specialized treatment in the same way that it is required for one general class as distinguished from another. Though it is as yet very imperfectly developed, the present tendency is for each institution to differentiate into a number of specialized departments, each designed to provide the proper treatment for one of these types. Finally, within the last decade beginnings have been made in what is likely to be an important future development, namely the non-institutional care of the less pronounced and confirmed types of delinquents, particularly of delinquent minors. The developments along this line have, up to the present, consisted chiefly in the adoption of parole systems in all the State penal, reformatory and correctional institutions and in a more liberal use of the suspended sentence and probation. The recently established Municipal Probation Court of Philadelphia is a pioneer in Pennsylvania in this promising new development in the preventive treatment of the less confirmed type of delinquents.