The only rules they can adopt, are of a general nature; founded on the principles already developed. They should endeavor to proportion their food to the amount of the exercise they ordinarily take. If they take but little exercise, they should eat but little food in comparison with those who are much in the open air and take much exercise; and their food should be chiefly vegetable, and not animal. But how often is it seen, that a student, or a man who sits all day in an office, or a lady who spends the day in her parlor and chamber, will sit down to a loaded table, and, by continuing to partake of the tempting varieties, in the end load the stomach with a supply, which a stout farmer could scarcely digest.

But the health of a family depends, not merely on the quantity of food taken; but very much, also, on the quality. Some kinds of food are very pernicious in their nature, and some healthful articles are rendered very injurious by the mode of cooking. Persons who have a strong constitution, and take much exercise, may eat almost any thing, with apparent impunity; but young children, who are forming their constitutions, and persons who are delicate, and who take but little exercise, are very dependent for health, on a proper selection of food.

There are some general principles, which may aid in regulating the judgement on this subject.

It is found, that there are some kinds of food which afford nutriment to the blood, and do not produce any other effect on the system. There are other kinds, which are not only nourishing, but stimulating, so that they quicken the functions of the organs on which they operate. The condiments used in cookery, such as pepper, mustard, and spices, are of this nature. There are certain states of the system, when these stimulants are beneficial; but it is only in cases where there is some debility. Such cases can only be pointed out by medical men. But persons in perfect health, and especially young children, never receive any benefit from such kind of food; and just in proportion as condiments operate to quicken the labors of the internal organs, they tend to wear down their powers. A person who thus keeps the body working under an unnatural excitement, lives faster than Nature designed, and the sooner the constitution is worn out. A woman, therefore, should provide dishes for her family, which are free from these stimulating condiments, and as much as possible prevent their use. It is also found, by experience, that animal food is more stimulating than vegetable. This is the reason why, in cases of fevers, or inflammations, medical men forbid the use of meat and butter. Animal food supplies chyle much more abundantly than vegetable food does; and this chyle is more stimulating in its nature. Of course, a person who lives chiefly on animal food, is under a higher degree of stimulus than if his food was chiefly composed of vegetable substances. His blood will flow faster, and all the functions of his body will be quickened.

This makes it important to secure a proper proportion of animal and vegetable diet. Some medical men suppose, that an exclusively vegetable diet is proved, by the experience of many individuals, to be fully sufficient to nourish the body; and bring, as evidence, the fact, that some of the strongest and most robust men in the world, are those, who are trained, from infancy, exclusively on vegetable food. From this, they infer, that life will be shortened, just in proportion as the diet is changed to more stimulating articles; and that, all other things being equal, children will have a better chance of health and long life, if they are brought up solely on vegetable food.

But, though this is not the common opinion of medical men, they all agree, that, in America, far too large a portion of the diet consists of animal food. As a nation, the Americans are proverbial for the gross and luxurious diet with which they load their tables; and there can be no doubt that the general health of the Nation would be increased, by a change in our customs in this respect. To take meat but once a day, and this in small quantities, compared with the common practice, is a rule, the observance of which would probably greatly reduce the amount of fevers, eruptions, headaches, bilious attacks, and the many other ailments which are produced or aggravated by too gross a diet.

The celebrated Roman physician, Baglivi, (who, from practising extensively among Roman Catholics, had ample opportunities to observe,) mentions, that, in Italy, an unusual number of people recover their health in the forty days of Lent, in consequence of the lower diet which is required as a religious duty. An American physician remarks, "For every reeling drunkard that disgraces our Country, it contains one hundred gluttons;—persons, I mean, who eat to excess, and suffer in consequence." Another distinguished physician says, "I believe that every stomach, not actually impaired by organic disease, will perform its functions, if it receives reasonable attention; and when we perceive the manner in which diet is generally conducted, both in regard to quantity and variety of articles of food and drink, which are mixed up in one heterogeneous mass,—instead of being astonished at the prevalence of indigestion, our wonder must rather be, that, in such circumstances, any stomach is capable of digesting at all."

In regard to articles which are the most easily digested, only general rules can be given. Tender meats are digested more readily than those which are tough, or than many kinds of vegetable food. The farinaceous articles, such as rice, flour, corn, potatoes, and the like, are the most nutritious, and most easily digested. The popular notion, that meat is more nourishing than bread, is a great mistake. Good bread contains one third more nourishment than butcher's meat. The meat is more stimulating, and for this reason is more readily digested. A perfectly healthy stomach can digest almost any healthful food; but when the digestive powers are weak, every stomach has its peculiarities, and what is good for one, is hurtful to another. In such cases, experiment, alone, can decide, which are the most digestible articles of food. A person, whose food troubles him, must deduct one article after another, till he learns, by experience, which is the best for digestion. Much evil has been done, by assuming that the powers of one stomach are to be made the rule in regulating every other.

The most unhealthful kinds of food, are those, which are made so by bad cooking; such as sour and heavy bread, cakes, pie-crust, and other dishes consisting of fat, mixed and cooked with flour; also rancid butter, and high-seasoned food. The fewer mixtures there are in cooking, the more healthful is the food likely to be.

There is one caution, as to the mode of eating, which seems peculiarly needful to Americans. It is indispensable to good digestion, that food be well chewed and taken slowly. It needs to be thoroughly chewed, in order to prepare it for the action of the gastric juice, which, by the peristaltic motion, will be thus brought into universal contact with the minute portions. It has been found, that a solid lump of food requires much more time and labor of the stomach, than divided substances. It has also been found, that, as each bolus, or mouthful, enters the stomach, the latter closes, until the portion received has had some time to move around and combine with the gastric juice; and that the orifice of the stomach resists the entrance of any more, till this is accomplished. But, if the eater persists in swallowing fast, the stomach yields; the food is then poured in more rapidly than the organ can perform its duty of digestion; and evil results are sooner or later developed. This exhibits the folly of those hasty meals, so common to travellers, and to men of business, and shows why children should be taught to eat slowly.

After taking a full meal, it is very important to health, that no great bodily or mental exertion be made, till the labor of the stomach is over. Intense mental effort draws the blood to the head, and muscular exertions draw it to the muscles; and in consequence of this, the stomach loses the supply which it requires when performing its office. When the blood is thus withdrawn, the adequate supply of gastric juice is not afforded, and indigestion is the result. The heaviness which follows a full meal, is the indication which Nature gives of the need of quiet. When the meal is moderate, a sufficient quantity of gastric juice is exuded in an hour, or an hour and a half; after which, labor of body and mind may safely be resumed.

When undigested food remains in the stomach, and is at last thrown out into the bowels, it proves an irritating substance, producing an inflamed state in the lining of the stomach and other organs. The same effect is produced by alcoholic drinks.

It is found, that the stomach has the power of gradually accommodating its digestive powers to the food it habitually receives. Thus, animals, which live on vegetables, can gradually become accustomed to animal food; and the reverse is equally true. Thus, too, the human stomach can eventually accomplish the digestion of some kinds of food, which, at first, were indigestible.

But any changes of this sort should be gradual; as those which are sudden, are trying to the powers of the stomach, by furnishing matter for which its gastric juice is not prepared.

In regard to the nature of the meals prepared, the breakfast should furnish a supply of liquids, because the body has been exhausted by the exhalations of the night, and demands them more than at any other period. It should not be the heartiest meal, because the organs of digestion are weakened by long fasting, and the exhalations. Dinner should be the heartiest meal, because then the powers of digestion are strengthened, by the supplies of the morning meal. Light and amusing employments should occupy mind and body for an hour or more after a full meal.

But little drink should be taken, while eating, as it dilutes the gastric juice which is apportioned to each quantity of food as it enters the stomach. It is better to take drink after the meal is past.

Extremes of heat or cold are injurious to the process of digestion. Taking hot food or drink, habitually, tends to debilitate all the organs thus needlessly excited. In using cold substances, it is found that a certain degree of warmth in the stomach is indispensable to their digestion; so that, when the gastric juice is cooled below this temperature, it ceases to act. Indulging in large quantities of cold drinks, or eating ice-creams, after a meal, tends to reduce the temperature of the stomach, and thus to stop digestion. This shows the folly of those refreshments, in convivial meetings, where the guests are tempted to load the stomach with a variety, such as would require the stomach of a stout farmer to digest, and then to wind up with ice-creams, thus destroying whatever ability might otherwise have existed, to digest the heavy load. The fittest temperature for drinks, if taken when the food is in the digesting process, is blood heat. Cool drinks, and even ice, can be safely taken at other times, if not in excessive quantity. When the thirst is excessive, or the body weakened by fatigue, or when in a state of perspiration, cold drinks are injurious. When the body is perspiring freely, taking a large quantity of cold drink has often produced instant death.

Fluids taken into the stomach are not subject to the slow process of digestion, but are immediately absorbed and carried into the blood. This is the reason why drink, more speedily than food, restores from exhaustion. The minute vessels of the stomach inhale or absorb its fluids, which are carried into the blood, just as the minute extremities of the arteries open upon the inner surface of the stomach, and there exude the gastric juice from the blood.

When food is chiefly liquid, (soup, for example,) the fluid part is rapidly absorbed. The solid parts remain, to be acted on by the gastric juice. In the case of St. Martin,⁶ in fifty minutes after taking soup, the fluids were absorbed, and the remainder was even thicker than is usual after eating solid food. This is the reason why soups are deemed bad for weak stomachs; as this residuum is more difficult of digestion than ordinary food. In recovering from sickness, beef-tea and broths are good, because the system then demands fluids to supply its loss of blood.

Highly-concentrated food, having much nourishment in a small bulk, is not favorable to digestion, because it cannot be properly acted on by the muscular contractions of the stomach, and is not so minutely divided, as to enable the gastric juice to act properly. This is the reason, why a certain bulk of food is needful to good digestion; and why those people, who live on whale oil, and other highly-nourishing food, in cold climates, mix vegetables and even sawdust with it, to make it more acceptable and digestible. So, in civilized lands, bread, potatoes, and vegetables, are mixed with more highly-concentrated nourishment. This explains why coarse bread, of unbolted wheat, so often proves beneficial. Where, from inactive habits, or other causes, the bowels become constipated and sluggish, this kind of food proves the appropriate remedy. One fact on this subject is worthy of notice. Under the administration of William Pitt, for two years or more, there was such a scarcity of wheat, that, to make it hold out longer, Parliament passed a law, that the army should have all their bread made of unbolted flour. The result was, that the health of the soldiers improved so much, as to be a subject of surprise to themselves, the officers, and the physicians. These last came out publicly, and declared, that the soldiers never before were so robust and healthy; and that disease had nearly disappeared from the army. The civic physicians joined and pronounced it the healthiest bread; and, for a time, schools, families, and public institutions, used it almost exclusively. Even the nobility, convinced by these facts, adopted it for their common diet; and the fashion continued a long time after the scarcity ceased, until more luxurious habits resumed their sway. For this reason, also, soups, gellies, and arrow-root, should have bread or crackers mixed with them. We thus see why children should not have cakes and candies allowed them between meals. These are highly-concentrated nourishments, and should be eaten with more bulky and less nourishing substances. The most indigestible of all kinds of food, are fatty and oily substances; especially if heated. It is on this account, that pie-crust, and articles boiled and fried in fat or butter, are deemed not so healthful as other food.

The following, then, may be put down as the causes of a debilitated constitution, from the misuse of food. Eating too much, eating too often, eating too fast, eating food and condiments that are too stimulating, eating food that is too warm or too cold, eating food that is highly-concentrated, without a proper admixture of less nourishing matter, and eating food that is difficult of digestion.