Instead of using up energy, the will so used brings out latent stores of energy that would not otherwise be employed and thus adds to the available amount of vitality for the individual. Doctor Thomas Addis Emmet, only just dead, over ninety, in his younger years as a busy medical practitioner never kept a horse. It would not be difficult to cite many other examples among men who lived to advanced old age and who considered that they owed their good health and long life to daily habits of outdoor exercise. {148} CHAPTER X THE WILL TO EAT "If your will want not, time and place will be fruitfully added." _King Lear_. Eating is usually supposed to be entirely a matter of appetite which instinct directs to the best possible advantage of the individual. This is quite true for those who are living the outdoor life that is normal or at least most healthy for men, and when they are getting an abundance of exercise, and may I add also have not too great a variety of food materials in tempting form presented to them. Under the artificial not to say unnatural conditions which men have to a great extent created for themselves in city life, confined at indoor sedentary occupations, some of them--and they are much more numerous than is usually imagined--eat too little, while a great many, owing to stimulation of appetite in various ways, eat too much. Eating therefore for health's sake has to be done through the will and as a rule by the {149} formation of deliberate habits. It is easy to form habits either of defect or excess in the matter of eating and indeed a great deal of the ill health to which mankind is liable is due to errors in either of these directions. Having disturbed nature's instincts for food in modifying the mode of life to suit modern conveniences, we have now to learn from experience and scientific observations what we should eat and then make up our minds to eat such quantity and variety as is necessary to maintain health and strength in the particular circumstances in which we are placed.