*The Habit of Self-control.*—Much of the needless waste of nervous energy, including that of worrying over trivial matters, may be prevented through the exercise of self-control. From the standpoint of the nervous system, the present age differs from the past mainly in supplying a greater number and variety of nerve stimuli. Self-control means the ability to suppress activities that would result from undesirable stimuli and to direct the bodily activities into channels that are profitable. Self-control, therefore, is not only to be exercised on occasions of great emergency, but in the everyday affairs of life as well. It is even more important that the daily toiler at his task be able to keep the petty annoyances of life from acting as irritants to his nervous system than that he keep cool during some great calamity. The habit of self-control is acquired mainly through the persistent effort to prevent any and all kinds of petty annoyances from affecting the nerves or the temper. *Nervousness.*—Self-control is much more easily practiced by some than by others. This is due partly to habit, but is also due to an actual difference in the degree of sensitiveness, or irritability, of the nervous systems of different people. One whose nervous system tends to respond too readily to any and all kinds of stimuli is said to be "nervous." This condition is in some instances inherited, but is in most cases due to the wasteful expenditure of nervous energy or to the action of some drug upon the body. Excess of mental work, too much reading, long-continued anxiety, eye strain, and the use of tea, coffee, alcohol, tobacco, or other drugs, including many of those taken as medicines, are known to cause nervousness. Nervousness is not only a source of great annoyance, both to one’s self and to others, but is a menace to the general health. The first step toward securing relief from such a condition is the removal of the cause. The habits should be inquired into and excesses of all kinds discontinued. In some instances it may be necessary to _have the eyes __examined_ and glasses fitted by a competent oculist.(109) The nervous energy should be carefully economized and the habit of self-control diligently cultivated. Special exercises that have for their purpose the equalizing of the circulation and the strengthening of the blood vessels of the neck and the brain also have beneficial effects.