Lombroso’s daily contact with prisoners awaiting trial, owing to his official position as medical officer to the prison at Turin, the criticisms passed from the legal side upon his doctrine of the “born criminal,” and the continued exchange of ideas with so distinguished an expert in the theory of jurisprudence as Enrico Ferri, led him in twenty years’ ensuing work, in which he accumulated an enormous mass of observations of his own, and utilized the entire international literature of the subject, to study the criminal by passion, the occasional criminal (economic etiology of crime), the habitual criminal, and other abnormal categories of criminals (in addition to the born criminal)—criminal alcoholics, criminal lunatics, and criminal epileptics. The results of all this work were incorporated in the third, fourth, and fifth editions of “L’uomo delinquente.” From the year 1880 onwards he was assisted in this gigantic undertaking by able personal assistants, and from this year dates the issue of his _Archivia di psichiatria_, in the production of which he enjoyed the collaboration of an international circle of colleagues. At the same time, the doors of all Italian prisons were open, not to him only, but also to his pupils and fellow-workers—an advantage which I myself occasionally enjoyed. Beltrani-Scalia,[23] the chief of the Italian prison administration, placed at Lombroso’s disposal the entire official material of his department; and Lombroso utilized this, not only to strengthen and develop his theories, but also for the foundation of a unique criminal museum, and for the preparation of carefully-thought-out plans of penal reform. From every quarter materials streamed in, by which hundreds of heads and hands were kept busy. Lombroso’s grown-up daughters, Paola and Gina, became readers, translators, actuaries, and sub-editors; and the house in the great square of Turin, from which in the evening can be seen the sunset glow on the peaks of the western Alps, became, not only the collecting centre of the materials pouring in from every direction (ultimately even from the slowly-moving Anglo-Saxon world), not only the source of an extensive journalistic propaganda (in Germany furthered by Maximilian Harden’s paper, _Zukunft_, which even then had a wide and increasing circulation), but, in addition, the meeting-place of numerous foreign investigators engaged in the study of the social and biological sciences. Here the heavy red wine of Piedmont, which was supplied with no sparing hand, loosened many tongues; but wine was assuredly not the sole enlivening element in the house, in which distinguished simplicity and a patriarchal atmosphere combined to melt the chill reserve no less of the Prussian Privy Councillor than of the English University Professor, so that the conversation of all was brilliant and unrestrained.