A correct view about the purpose of the Missions must determine the qualities needed in a missionary. The first requisite is adaptability: he has to form new Christians, and has to adjust himself to a new and foreign outlook and way of life. While the development of communications and health services has rendered the possession of exceptionally strong bodily qualities generally unnecessary to-day, and the variety and extent of mission work gives an opportunity for almost all kinds of talents and types of mind, there are certain general qualities which are still necessary for all engaged in mission work.

Pope Pius XI stressed especially the dangers of nationalism among missionaries, and these are obvious, though nowadays such tendencies are less than formerly. Yet they are not entirely gone, and Pope Pius XII urges the missionary to make of his Mission a second fatherland, an adaptation not possible to some characters.