Habit and Food.—Most of our likes and dislikes for food are neither physical nor physiological, but simply habitual. We have become accustomed to certain things, and so we like them. We are unaccustomed to them, and do not care for them. It is amusing when people put forward these lacks of habituation as if they were physiological idiosyncracies. Many thin people do not like butter and milk. The real reason for this is not any peculiarity of digestion, or any gastric incompatibility, at least in 99 cases out of every 100, but the mere fact that they are not habituated to their use. That is one of the reasons why they are thin. Our tastes for curious foreign foods are nearly all deliberately acquired. Not one in ten ordinary Americans likes olives or caviar when first tasted. Nearly every curious article of food is "caviar to the general" at first trial. Later it becomes impossible to understand how we could have had any objection to them. At times, even an actual craving for them asserts itself as a consequence of the habitual use, and then deprivation means positive discomfort.

Slow Eating.—One of the most valuable habits that a man can cultivate, but one of the most difficult to acquire in our time, is that of eating slowly. Most Americans bolt their food to a degree that would be quite appalling to them if they realized what they were doing. Pieces of potatoe as large as the end of the thumb are swallowed. Bread and milk may be eaten so hurriedly as to be as potent a source of digestive disturbance as fried onions. There seems no doubt from what we know of Fletcher's experience and Chittendan and Follin's studies that a man derives more nutrition from food that is masticated properly, that he can get along and do his work on less material and that, above all, there is not the same tendency for him to put on weight that is so common among people after reaching middle age.

Sir Andrew Clarke used to have his patients chew a definite number ol times on each bite—say thirty times. Even so great a man as Gladstone submitted to this rule and gradually learned to accustom himself to eating very slowly. Fletcher's system of chewing the food until it passes down the esophagus of itself without any swallowing effort is a better rule. It is a surprise to most people how unconsciously swallowing can be accomplished in this way and how little liquid is needed in order to prepare food to be swallowed. The formation of the habit, however, is not an easy one. Persistence and frequent reminders are needed, or else the beginnings of the habit are soon dissipated and old bolting habits reassert themselves.{232}

Water Drinking.—In drinking, habit is as supreme as in eating. The majority of people who work outside and perform muscular labor crave and take an abundance of water. Many of those who live indoors, especially in steam-heated houses, may need it quite as much if not more, but get out of the habit of drinking water. As we need about three quarts of water per day for use in our economy, this no water habit often becomes a serious factor in the production of physiological disturbances. We have replaced water drinking and the milk drinking of the olden times by tea and coffee, and as these are stimulants, habits form very readily with regard to them. I have known people who were sure they would be miserable without their half-dozen cups of tea or coffee each day, and who actually would be miserable for a few days, when deprived of it. They were seriously impairing the efficiency of their nervous system by so much stimulation. Unfortunately, it is just those whose nervous systems have least stability, and are already the subjects of more stimulation by conscious introspection than is good for them, that are most likely to form the tea and coffee habits, and who are most harmed by them, though they find it hard to understand the reason therefor.

Air and Exercise Habits.—Habits with regard to exercise and fresh air are particularly important. In this matter it is only habit that can be really helpful. To work at high pressure indoors for several days, and then, when one is quite on edge, to take a lot of severe physical exercise is not good. Every human being should go out between meals. I am not one of those who believe much in exercise for exercise's sake—what is needed is fresh air. Our sanatorium patients who sit out-doors all day have fine appetites. The advice to a busy man that he must form the habit of being out between every two meals for from half an hour to an hour would usually evoke a strenuous protest, but all he needs to do is to get up half an hour earlier and walk down to his office, and if he will walk back in the evening he will have plenty of air and exercise between his meals.

Change of Habits.—Patients do not want to change their habits. They come to a doctor to be treated. They want some medicine that will, without further inconvenience, rid them of certain discomforting symptoms. At the beginning, at least, patients resent interference with their habits. They are quite satisfied, and to modify them requires an effort that must be continued for some time. The changing of old habits and the formation of new habits are most important for the ordinary ills to which mankind is prone. Modifications of habit constitute real hygiene and are not mere corrections of symptoms, permitting the habits that have led up to them to go on.

Patients may conclude that it is too much trouble to change their habits. We all know persons who feel that they can not give up their coffee. As to whether or not the modification of a habit is worth the trouble it involves, the patient must be the judge after the case is put properly before him. It is possible that he may learn to endure the inconvenience given him by his symptoms rather than to stand the inconvenience of changing a nicely settled habit, and forming a new one. The reward should be put very plainly before him, however, and besides, the consequences of his habit in the future should be suggested so that he may realize just what it will lead to.{233}