The papers in this book treat of six sacraments, and of the general nature of sacraments; the Holy Eucharist is omitted , as having been the general subject of the Summer School of 1922. Without this separate treatment of so vast a theme it would have been impossible to take the sacraments as a general subject. In the matter of the sacraments it is nor primarily a question of what the Church teaches, but of what she does; and more than this, of what she always has done and always will do. She insists upon her children submitting to her action. Her infallibility is involved because of the teaching that goes to explain that action.