study and the other things in the world. Constant attention to one thing narrows our minds, until we fail to see the very thing we are looking at. Our lives are thus really passed in a constant flitting from one more or less partial and distorted view of things to another, from this one-sided judgment to that. Change the book you are reading, and your whole notion of the universe suffers some momentary change also. Think this week in the fashion of Carlyle, attending to things as he brings them to your attention, and human life — in fact, the whole world of being as you thought of it last week, when you were following some other guide — becomes momentarily clouded. This truth seems out of relation to that. Your change of attention qualitatively alters your apprehension of truth. Attending now even to the same things, you view them in new lights. The alteration of mental attitude becomes confusing to yourself. But refuse to make any such changes, settle down steadfastly to some one way of regarding all things, and your world becomes yet more misty. You see only a few things, and those in such a bad light that you are in danger of utter darkness. Frequent change of mental view (we of course do not mean constant change of creed or of occupation, but only frequent alteration of the direction of our thought) is essential to mental health. Yet this alteration implies at least some temporary change in our knowing powers, and so some change in our appreciation of truth.
Before going on to speak of the effect of our own activity upon our knowledge, when attention is com-
