Research on the history of criminology that has proliferated in the last twenty years has highlighted the importance of racial and eugenic ideas in the development of this new field of study. As historian Nicole Rafter has insightfully noted, the establishment of criminology drew from three of the most "disturbing" ideas of the nineteenth century: the idea of evolution, the theory of biological determinism and the theory of heredity of acquired characteristics. On these ideas was based the theory of degeneration, which classified criminals along with the mentally ill, the poor, homosexuals and prostitutes as "degenerates." Scientific racialism of this kind was common among penal professionals at the time. It constituted the primary aetiology of criminal behaviour, irrespective of the importance accorded to sociological causes (Rafter, 2009, xv-xix).2 National case-studies as well as studies of the transnational movement of criminological ideas and practices have underlined the various factors that determined the crucial role of these ideas in the development of criminology. 1 To quote historian Richard F. Wetzell: "In the last quarter of the nineteenth century the development of criminology into a recognized scientific field was strongly influenced and greatly accelerated by three developments common to most of western Europe: the publication and dissemination of Lombroso's theory of the 'born criminal'; the rise of a new penal reform movement that called for criminological research; and increasing interest in criminological questions among psychiatrists" (Wetzell, 2000, 28). Researchers agree that theories attributing criminal behaviour to biology were already broadly widespread, but the impact of the Italian positivist school consolidated the shift from crime to criminals and made criminological discourse more coherent (Wetzell, 2000, 30-35; Rafter, 2009, xv). 2