Chapter XV) are concerned in it. All have known people (Part 1)

Chapter XV) are concerned in it. All have known people who can go to sleep the instant they lie down; and they can do this —it would almost seem by an act of the will —because they have long done it. It is a power which can indeed be cultivated too well; by too frequent repeti- tion of the process of taking a nap, and by sleeping too long at night, there may be acquired a diminished irrita- bility of the nerve cells, which makes attention to work a very difficult matter, and long-sustained attention almost impossible. Those in this condition may escape the danger of nervous prostration, but they impair their usefulness in life. » : The true path, as in other matters of personal hygiene, is that between these extremes. When one rises at seven or eight in the morning, a short period of rest in the after- noon is sufficient; the persistent practice of the act of relaxation every hour or less is apt to lead to loss of mus- cular tone and of nervous efficiency in general. At the same time, the habit of momentary relaxation in the midst of the day’s work is a valuable aid, partly in bettering conditions at the time, but chiefly in retaining the power to relax when it is wanted for longer periods of rest. HS 344 THE HUMAN MECHANISM 10. Drugs are Delusive and Dangerous. — The physiolo- gist cannot condemn too strongly the substitution of stim- ulants for the proper regulation of work and rest. The reader will see at once what this course of action may be expected to accomplish ; the stimulant is an antagonist of relaxation; the nerve cell becomes more and more irri- table as it is pushed harder and harder; finally it reaches either the condition of excessive irritability or else that of being unable to work without the stimulant. It has adapted itself to the presence of the stimulant in its environment, it is trained to work under those conditions, and it cannot . work without them. It may be safely asserted that, in gen- eral, the time above all others when stimulants should not be used is when .we are tired out ; to use stimulants regu- larly, day after day, in place of rest is shown by experience to be one of the most dangerous of mistakes. Nor, on the other hand, can we condemn too strongly the use of narcotics to produce sleep. Probably none of these drugs are capable of producing normal sleep; and while in times of emergency the physician must have recourse to them, they should never be relied upon in place of the hygienic conduct of the whole life. Many of them, and some of those in common use, are very danger- ous, and none of them is known to be above reproach. 11. The Influence of Mental and Moral States. — Finally, it must also be remembered that psychical processes exert a profound influence upon the well-being of the brain and spinal cord. It is a matter of common experience that emotions, feelings, moods, etc., profoundly influence human conduct, and so indirectly affect health, especially the health of the nervous system. It is also certain that they exert a more direct physiological influence on the bodily functions ; the changes which, emotions produce in the heart beat are good examples of other changes which are none the less important because they do not lend themselves HYGIENE OF THE NERVOUS SYSTEM 345 so readily to observation. The bestowal of a healthy atten- tion upon the moral aspects of conduct is a legitimate and essential part of personal hygiene ; and it is not too much to say that much of the ill health from which men and women suffer is to be traced primarily to the absence of sound moral sense or to its abnormal or perverted devel- opment. Care and worry often cause weariness and loss of sleep which even diversion and muscular exercise cannot overcome. They seldom trouble the young, but as age advances they are sometimes inevitable. Efforts should be made to avoid them, as far as possible, by a wise order- ing of life, by forethought, thrift, economy, sobriety, hon- esty, and the like, which tend to “a light heart” and “a clear conscience.” A heavy heart and a clouded conscience tend to unhappiness, anxiety, wakefulness, and other phys- ical ills. 12. ‘‘Mental’’ Cures of Disease. — It has been shown that mental conditions are far from being without influence upon the activities of the body, even leaving out of account the voluntary muscles. The effect of emotions upon the heart has been referred to, and so has the psychic secretion of gastric juice. It is known that the movements of the alimentary canal are readily modified by events in conscious life. In the hypnotic state the effect of sugges- tion upon functions which we habitually regard as invol- untary is even more striking. Facts like these have led many to the rash assumption that there is no limit to the domination of the mind over physiological processes. In numerous cases the ascendency which some have gained over certain forms of disease has been as surprising to others as it has been gratifying to themselves. Beyond question the righting of disordered functions and the sup- pression of pain have been frequently attained, and this fact makes it easy to see why so great a following has been drawn to a belief in the universality of mental power. 346 THE HUMAN MECHANISM But certain dangers are always involved in the attempt to overcome disease by resolutely forgetting it and denying its existence. The feeling of pain may at times be ban- ished by believing that it does not exist, but this may be quite as undesirable as self-inflicted blindness or deafness. While relief from pain may frequently favor recovery by promoting rest and nutrition, it may at other times sim- ply mean the loss of warnings which deserve to be heard. Where there is grave organic disease, this may move on to a fatal issue even while the deluded subject consist- ently ignores its course. It is not wise to try to annul the effects of a disease in consciousness when both cause and effect can be removed by rational medical treatment. Hypnotism may relieve a toothache, but it is not claimed that it will mend a decaying tooth. The dentist’s filling, which does both, is the type of medical as contrasted with psychical methods in dealing with acute disease. Espe- cially foolish is it to ignore or deny the actual presence of infectious or contagious disease, for here delay menaces not only the patient but those about him. The conse- quences of this folly, when confined to its deluded victim, may end in virtual suicide; when they extend to others, they may fall little short of manslaughter. > (CABUNIE MDM Ee D0 DiS THE HYGIENE OF FEEDING The present chapter deals with certain hygienic con- siderations connected with the taking of food into the body, —its preparation, its cooking, its quantity, the fre- quency of our meals, and the adjustment of our habits of feeding to the other work of life. Mankind as a whole was probably never better fed than it is at present. The opening up of the New World with its vast fields of corn and wheat and its enormous pas- tures; the introduction of improved methods of agriculture, agricultural machinery, and education in agriculture; and especially the improvements in transportation facilities and in arts of food preserving (such as refrigeration and canning), —all these have immensely increased the avail- able food supply of the world and made famine and star- vation much more rare than formerly. It is now only in inaccessible places, such as the central parts of India, that great famines still occur. And yet in the midst of abundance it is still true that many men and women are poorly nourished; for it is the absorption of food by the blood and not merely the eating of meals which supplies the needs of the tissues. Hence the problem of alimentation in its widest sense involves not only the growing of food on farms or in gardens, and 1 Many practical points connected with alimentation have already been considered in Part I (see chapters on digestion and nutrition). Special reference may be made to Chapter XIII, p. 233, on the Choice of Foods and Nutrients. 047 348 THE HUMAN MECHANISM the preservation of this food so that it may be delivered in proper form to the consumer, but also the eating of it in such form and quantities and at such times as will insure its proper utilization, by the processes of digestion, for the needs of the body. 1. Appetite as a Guide in Feeding. — Nature herself has provided us with guides in the choice of food, and these guides are the sensations of hunger and thirst, and what we sum up in general under the term “appetite.” So long as these remain normal and unperverted, they are to be largely trusted; and, like all physiological functions, they are kept normal and unperverted, in the first place, by attention to the general health of the entire body. Appe- tite is apt to fail or become untrustworthy in the case of men or women who are suffering from lack of muscular activity or from mental worry. The care of the appetite is never a matter of direct attention to the appetite itself, but of maintaining the bodily conditions in which it nor- mally acts. Consequently the basic principle in securing proper nutrition is attention to the general health. A pa- tient suffering from indigestion once consulted a wise old doctor and began recounting the foods that agreed or disagreed with him, together with his innumerable symp- toms, until the doctor interrupted ‘him by saying, « The first thing you must do is to forget that you have a stomach.” The present chapter is not written for people like this patient, or for invalids, or for others suffering from indigestion in any one of its thousand forms. It is written for those who can, and will, first of all, take the needful muscular exercise and the needful rest; who will pay proper attention to clothing and bathing, to the heat- ing and ventilation of the home, to the avoidance of © dampness and other unfavorable conditions ; who will not abuse themselves by stimulants and narcotics. Those who prefer not to belong to this class, or who because of some HYGIENE OF FEEDING 349 constitutional disease cannot, must seek and depend upon medical advice as regards their habits of feeding. At the same time, to insure proper digestion and nutri- tion, more is required than attention to general hygiene. What additional precautions are required in the taking of food by persons leading an otherwise healthy life? It is in answer to this question that we shall attempt to give some suggestions. 2. Good Cooking as an Aid in Nutrition. — It has already been pointed out that digestion begins with the prepara- tion of the food by cooking, which serves three purposes. 1. It destroys parasites and disease germs. The impor- tance of this will be shown and emphasized elsewhere (Chapter XXXII). 2. It renders the food more appetizing (see p. 113). 3. It makes some foods more digestible by making them accessible to the action of the digestive juices; thus the connective tissue of animal foods, when heated in the pres- ence of water, swells, and is more easily acted on by the gastric juice, so that tough meat in this way is often made tender by boiling. The cellulose walls of the vege- table foods, on the other hand, are softened by cooking, the starch granules are swollen, and their envelopes burst (see p. 94). At the same time it is possible to render food less diges- tible by improper cooking. A piece of meat may “have the life cooked out of it”; and egg albumen, which in the raw state mixes rather easily with the gastric juice, may sometimes be boiled to a leathery consistency which ren- ders the action of the digestive juices a slow process. 3. Chewing of Food an Aid to Digestion. — It is unneces- sary to dwell at length upon the importance of chewing, or mastication. We have already seen that the word “ diges- tion’ is derived from the Latin words dis and gero, to tear apart or separate; and our studies of physiology have 350 THE HUMAN MECHANISM shown how the division of food into smaller and smaller masses is prerequisite to reasonable rapidity of solution and absorption. The student is also reminded of what has been said (p. 100) concerning the importance of caring for the teeth. Vegetable foods especially should be well chewed, partly" because the cellulose which holds them together is not readily acted on by the gastric juice, and partly because the thorough mixture with the saliva facilitates the gastric digestion of starch (p. 110). Meats also should be well masticated. The fact that a dog bolts his food with im- punity is no guide for civilized man, since, for one rea- son, human gastric juice contains much less acid and so acts less readily upon connective-tissue elements. Itis true that the “ quick lunch” thrives in busy places, but no one considers it hygienic. 4. Feeding in Relation to Gastric Digestion. — In order that gastric digestion may be efficient it is, of course, neces- sary that gastric juice shall be secreted in proper amount, and we have learned that the first step toward this secre- tion consists in the pleasurable sensations connected with the satisfaction of appetite. Consequently it is one of the first hygienic requisites of gastric digestion that the food shall be appetizing, and that the condition of the body and especially of the digestive system shall be such that the food shall be eaten with relish. This is not the same thing as saying that food which is appetizing will be digested; it merely means that food is more digestible for being appetizing, and that, when it is not enjoyed, its stay in the stomach is apt to be unduly prolonged. For this and other reasons the appetite should not be impaired by eat- ing candy, or by visiting the pantry between meals for something to eat; on the other hand, a good appetite should be encouraged by healthy living, by proper prepa- ration of the food, and even, as far as possible, by agreeable HYGIENE OF FEEDING 301 table appointments. There was wisdom as well as pleas- ure in the old custom of having a jester at the dinner table, and there is reason in the saying, “Laugh and grow fat.” 5. Excessive Quantity of Food. Overfeeding. — It is furthermore important that the amount of food eaten at _ one time be not excessive, and that the stomach under no circumstances be unduly distended. A large proportion of those cases of dyspepsia which have their origin partly or entirely in the conditions of feeding are due to overeating, which may take various forms. Too large a proportion of the total food may be taken at one meal, usually dinner ; or too many meals may be taken, — three should suffice ; or each of the three may be full-sized meals, —a very unde- sirable custom among those engaged in sedentary pursuits. We have seen that the one condition of life which calls for heavy feeding is that of muscular activity, whether in the performance of external work or for the production of heat in cold weather ; a person who is engaged in some occu- pation which involves large amounts of muscular work can and should have three full meals daily ; with others the habit is attended with considerable risk. Gluttony has always been a vice of the idle and luxu- rious. As the world has grown wiser it has become less common, because a larger intelligence makes it plain that gluttony defeats its own ends, and that the secret of the greatest pleasure in eating, as in everything, lies in temper- ance, not in excess. Many persons, however, without any desire or even any thought of gluttony, regularly overeat. These are usually healthy persons leading sedentary lives, “ blessed,” as they say, “ with a good appetite,” and because of quiet or even indolent disposition giving but small heed to muscular activity. As the years go by, such persons are apt to grow fat, and by and by to find themselves suffering from a weak heart, or shortness of breath, or something worse; seldom 302 THE HUMAN MECHANISM realizing, until it is too late, that overeating is the princv- pal cause of their undoing. If sufficient manual labor or other exercise of the skeletal muscles is practiced, trouble from overeating rarely comes. It is the sedentary, inactive, and indolent who suffer most from this source; for them a good appetite often proves to be a curse rather than a blessing, and a poor appetite, by preventing overeating, has often been a blessing, though a blessing in disguise. 6. Fried Foods. — Caution is required in the use of fried foods. When a layer of fat varnishes over a particle of food the digestive juices do not readily penetrate the mass, and digestion is to that extent impaired. This is not of so much importance in intestinal digestion, since in that portion of the alimentary canal the layer of fat is itself digested and removed ; the stomach, on the other hand, does not digest fat, and we can easily see how, because of its interference with the first processes of digestion in this organ, the use of too much fried food is unwise. Moreover, in frying, care should be taken to