The law of association is well known. We all know how familiar places and happenings will recall old feelings; we can realize this at any time by mentally reviving the association. By dwelling on the pain we had yesterday we are encouraging it to return to-morrow. By emphasizing the impression of an annoyance of to-day we are making it possible to suffer beyond expression from annoyances to come; and the annoyances, the pains, the disagreeable feelings will find their old brain-grooves with remarkable rapidity when given the ghost of a chance. I have known more than one case where a woman kept herself ill by the constant repetition, to others and to herself, of a nervous shock. A woman who had once been frightened by burglars refused to sleep for fear of being awakened by more burglars, thus increasing her impression of fear; and of course, if she slept at all, she was liable at any time to wake with a nervous start. The process of working herself into nervous prostration through this constant, useless repetition was not slow. The fixed impressions of preconceived ideas in any direction are strangely in the way of real freedom. It is difficult to catch new harmonies with old ones ringing in our ears; still more difficult when we persist in listening at the same time to discords. The experience of arguing with another whose preconceived idea is so firmly fixed that the argument is nothing but a series of circles, might be funny if it were not sad; and it often is funny, in spite of the sadness. Suppose we should insist upon retaining an unpleasant brain-impression, only when and so long as it seemed necessary in order to bring a remedy. That accomplished, suppose we dropped it on the instant. Suppose, further, that we should continue this process, and never allow ourselves to repeat a disagreeable brain-impression aloud or mentally. Imagine the result. Nature abhors a vacuum; something must come in place of the unpleasantness; therefore way is made for feelings more comfortable to one's self and to others. Bad feelings cause contraction, good ones expansion. Relax the muscular contraction; take a long, free breath of fresh air, and expansion follows as a matter of course. Drop the brain-contraction, take a good inhalation of whatever pleasant feeling is nearest, and the expansion is a necessary consequence. As we expand mentally, disagreeable brain-impressions, that in former contracted states were eclipsed by greater ones, will be keenly felt, and dropped at once, for the mere relief thus obtained. The healthier the brain, the more sensitive it is to false impressions, and the more easily are they dropped.