The transition between early experiments with agricultural penal colonies in the 1880s and the subsequent emphasis on penitentiary reformation was related to the emergence and consolidation of a project of so-called social hygiene between 1906 and 1924. The move toward prison reform anticipated the emergence of the social question in modern metropolises. The penitentiary was an integral part of building a liberal welfare state that had among its major tasks molding and shaping the lower classes' behavior and morals. Prison reform and scientific policing coexisted with the expansion of the state's role in social protection, such as infant care, maternity benefits, and social work. Even if the penitentiary did not work as its founders planned, it nonetheless played a key role in increasing vigilance, control and observation of the lower classes. The experiment in penal and welfare state intervention developed in Costa Rica much earlier than in any other country in the region. Notes