The majority are young men from sixteen to thirty (National Prison Association, ’95, page 311). Criminals are variously classified in the literature of penology and the parlance of the Courts. According to the frequency, turpitude and degree of their offenses they may be denominated, delinquents, misdemeanants, first offenders, or petty offenders, and felons, atrocious offenders, incorrigible criminals, defectives, recidivists,—those hardened in crime, and repeatedly suffering the penalty of their misdeeds without any sign of amendment. A better classification is one that indicates the psychological and social conditions under which crimes are committed.