It will be remembered by readers of the Journal that the subject of the classification of mental disorders was discussed at the Congress of Psychiatry, held at Antwerp in September last, and that certain members of the Congress representing different nationalities were appointed to obtain the best-recognised classifications of medico-psychologists in their respective countries, in the hope of obtaining an international system on which all might agree for practical purposes. The nomination of this Commission arose out of a paper read by M. Lefebvre, Professor in the University of Louvain, in which he himself laid down as types of mental disease, idiocy, cretinism, general paralysis, dementia, toxic forms of insanity, mania, melancholia, and circular insanity. The author did not confine himself to classification, but included in his statistical investigations, the number of insane persons in a given area, the causes of insanity in general, the duration of the disease, and its termination and mortality. However, the question of classification took precedence of all others.