The word “milieu” is one of those expressive French words which, to a large extent, defies translation into English. In the present connection it might be rendered, though inadequately, as the sphere of life, the atmosphere, the surroundings or the environment in which the individual Catholic habitually finds himself. If he is an apostle of Catholic Action it must be largely in this milieu, in these surroundings, that he exercises his apostolate. Hence the word “milieu” is of supreme importance to the proper understanding of Catholic Action, as the actual sphere of life is to the exercise of the apostolate.

For Catholic Action is essentially conditioned by the circumstances of our natural human lives. It is indeed precisely because the priest cannot enter into certain circles and so supernaturalize the lives of those who frequent them that the Pope appeals to the laity to take up this task and continue amongst their own friends and working companions the apostolate of the hierarchy. “In order to bring back to Christ these whole classes of men who have denied Him, we must gather and train from amongst their very ranks auxiliary soldiers of the Church . . . the first and immediate apostles of the working-men must themselves be workingmen, while the apostles of the industrial and commercial world should themselves be employers and merchants.” The apostolate must be exercised, according to the Pope, in the circles of our every-day life. It is only natural. Rightly or wrongly there are class-differences and the life and interests of one class are different from those of another. In our democratic country it is easier than elsewhere to move from one class to another and to find oneself accepted in a class higher than that into which one was born, but it is quite impossible to enter into one sphere of life and exert an influence there while remaining to a great extent in another.