The function of the will in health is mainly to prevent the formation of bad habits or break those that have been formed, but above all, to bring about the formation of habits that will prevent as far as is possible the development of tendencies to disease in the body, Man probably faces no more difficult problem in life than the breaking of a bad habit. Usually it requires the exercise of all his will power applied to its fullest extent. If there is a more difficult problem than the breaking of a bad habit it is the formation of a good one late in life because of the persistency of advertence and effort that is required. It is comparatively easy to prevent the formation of bad habits and also easy to form good habits in the earlier years. The organism is then plastic and yields itself readily and thus becomes grooved to the habit or hardened against it by the performance of even a few acts. {44} All the psychologists insist that after the period of the exercise of instinct as the basis of life passes, habit becomes the great force for good or for ill. We become quite literally a bundle of habits, and the success of life largely depends on whether these habits are favorable or unfavorable to the accomplishment of what is best in us. More than anything else health depends on habit. We begin by doing things more or less casually, and after a time a tendency to do them is created; then almost before we know it, we find that we have a difficult task before us, if we try not to do them. To begin with, the activity which becomes the subject of a habit may be distinctly unpleasant and require considerable effort to accomplish. Practically every one who has learned to smoke recalls more or less vividly the physical disturbance caused by the first attempt and how even succeeding smokes for some time, far from being pleasant, required distinct effort and no little self-control. After a time, the desire to smoke becomes so ingrained that a man is literally made quite miserable by the lack of it and finds himself almost incapable of doing anything else until he has had his smoke. {45} Even more of an effort is required to establish the habit of chewing tobacco, and it is even more difficult to break when once it has been formed. Any one who has seen the discomfort and even torments endured by a man who, after he had chewed tobacco for many years, tried to stop will appreciate fully what a firm hold the habit has obtained. I have known a serious business man who almost had to give up business, who lost his sleep and his appetite and went through a nervous crisis merely by trying to break the habit of chewing tobacco.