THERE is no part of the human system which has such a controlling influence over the whole body, as respects health or disease, as the digestive organs. Any derangement in these, especially the stomach, calls up a sympathy of action from the whole animal economy. Nearly all the morbid actions found in the general system, are produced from causes, first operative on the stomach.

Hence, keeping the digestive system in a healthy state, secures, as a general rule, a healthy action in every other part of the physical organization. Therefore, to know something of the anatomy and physiology of the digestive organs, together with the laws of digestion, seems indespensable for every individual who would know how to take care of his health. By the term “digestive organs,” is intended the mouth, stomach, liver, and bowels, including the whole length of this canal is a lining membrane, called the mucous membrane, which continues from the lips to the opposite extremity; this membrane is filled through its whole extent with minute blood vessels, and in some parts, abundantly supplied with fine filaments of nerves. This membrane has important functions to perform in the process of digestion; it is a membrane of much delicacy of structure. Its healthy action is easily deranged, and when impaired in one part, becomes, by sympathy, deranged in every part.

THE MOUTH.

The mouth, with its teeth and glands, commences the digestive process; the teeth are to masticate the food; the salivary glands give important aid to digestion. There are three pairs of glands, which pour the fluid they secrete, into the mouth; this fluid is called saliva; the efforts of chewing food excites these glands, and promotes the secretion of saliva, which is essential to the healthy digestive process.

THE STOMACH.

The stomach is the most important organ of digestion. It has three coats; that which has most to do with digestion is the mucous coat, which lines it; this coat is supposed to furnish, by its glands, what is called gastric juice, which is the principal agent of digestion. The stomach is abundantly supplied with nerves, and holds a very powerful sway over the whole nervous system—so that, when the stomach is under the influence of disease, either acute or chronic, the whole system is immediately in a state of suffering. To secure, then, a healthy organization, the stomach must be kept in health.

THE LIVER.

This organ is also essential to digestion; it furnishes the bile; it is the largest gland in the body, and its office seems to be to gather from and carry out of the system substances which, if retained, might prove hurtful. When the liver is inactive, we have what is called the jaundice; the liver failing to take up from the system that substance which forms the bile. When this is the case, a yellow substance is found diffused throughout the whole body, and it exhibits a yellow tinge. The bile, when properly secreted and discharged, meets the contents of the stomach as discharged into that part of the bowels nearest the stomach, and is there supposed to assist in the process of separating the nutritious part of the contents from the refuse, which is to pass off by the bowels; but its more important office is, doubtless, to rid the passage of the refuse, or the fÆces, by evacuation. The bile seems to be nature’s appropriate stimulus to the bowels, without which costiveness, and other irregularities, are likely to ensue.

THE BOWELS.

The bowels contain the absorbent vessels, which take up the nutritious part of the food and carry it into the circulation of the blood, for the support of the system; they also convey the refuse part of the food out of the body.

MASTICATION.

Mastication, or chewing, is the first step in the process of digestion. When food is taken, it should be thoroughly masticated, before it is suffered to pass into the stomach, or it is unprepared for the action of the gastric juice. Besides this, the action of chewing causes the food to be mixed with the saliva, which is an important item in the preparation of it for the action of the stomach and its juice. The food should be taken with sufficient moderation, to give time for the process of mastication, and the discharge of saliva from the glands of the mouth. Eating fast, or even talking while chewing, besides its incongruity with politeness and good breeding, is directly at war with thorough mastication.

Many persons seem to think, that hurrying their meals to save time is economy; their business drives them, and they drive their time of meals into the smallest possible compass. This is miserable economy; for, when they hurry down their food, half chewed and half moistened with saliva, it deranges the process of digestion throughout, and, as a consequence, the food not only sits bad on the stomach, and in time causes dyspepsia, but fails to accomplish the sole object of taking it—the nourishment of the body. In order to derive nourishment from food, it must be well digested; hence it must be well masticated. When, therefore, we hurry our eating, we hasten our steps on the wrong road; time curtailed in eating, is worse than hiring money at three per cent. a month. If we cannot spare time to eat, we had better not eat at all; this idea cannot be too deeply impressed upon the minds of all. Thousands, by this kind of careless and reckless eating, have, found themselves the victims of dyspepsia, and all its attendant train of evils; the digestive organs may bear the abuse awhile, without giving many signs of trouble, but the penalty of that broken law must sooner or later come; and it may come in the form of a broken constitution.

CHYMIFICATION.

Chymification, or the transformation of food into chyme, is the most important step in the process of digestion. The food, after mastication, passes into the stomach; here it is formed into a homogenous mass, partly fluid and partly solid, which is called chyme. What is the exact philosophy of this process, has been a matter of some discussion, into which it is not necessary now to enter; nor is it yet satisfactorily settled, so as to admit of any definite instructions being given. The theory which is now generally received, respecting the manner in which the stomach acts upon food, is, that the gastric juice possesses a solvent power, by which the food becomes reduced to a uniform mass; the solvent power of the gastric juice is very great in a healthy, vigorous stomach, but varies in strength according to the energy of that organ. The solvent power of the gastric juice is evidently controlled by the vital principle of life; while the gastric juice of a healthy stomach acts vigorously upon the hardest kinds of food; yet sometimes, when it comes in contact with anything possessed of the principles of life, its power is stayed—worms, while living, are not affected by it, but when destroyed, are often digested. The gastric juice also possesses the property of coagulating liquid albuminous substances; the stomach of the calf is used for this purpose, by the dairy-woman, in making cheese; and when the infant throws up its milk, because the stomach is too full, that milk will be more or less curdled—and instead of considering this curdling an indication of disease, it should be accounted a symptom of a good, healthy stomach.

The time ordinarily occupied in the process of chymification, when the food has been properly masticated, has been found to be four or five hours; the three first hours of the period, is occupied in the process of intermixing the food, after it enters the stomach, with the gastric juice. After this is accomplished, an alternation of contraction and expansion of the stomach, or a kind of churning motion takes place, and continues until the whole mass is converted into chyme, and conveyed to the first intestines, or duodenum, to undergo another change.

CHYLIFACTION.

Chylifaction, or the formation of chyle, is the next great step in the process of digestion. This takes place in the duodenum; the chyme from the stomach is let into the intestines little by little; a valve at the lower opening, or outlet of the stomach prevents it from passing any faster than it can be disposed of, in the formation of chyle. This fluid is a thin, milky liquid, extracted from the chyme, and then taken up by absorbent vessels, called lacteals; the chyme passes slowly through the duodenum, and, in doing so, becomes mixed with another fluid furnished from the pancreas, or sweetbread, and the bile from the liver; passing slowly through this large intestine, ample time is given for the lacteal to take up all that is valuable, to be carried into the circulation, for the nourishment and support of the system. This chyle, taken up by the lacteals, is directly converted into blood, and, in many of its characteristics, it very closely resembles blood. The process by which this conversion is carried on, is called absorption; that class of absorbent vessels called lacteals, are not only found in the first intestine, or duodenum, but are distributed along the small intestines, for the purpose, as before stated, of conducting the chyle in its appropriate course, for the formation of blood.

EVACUATION.

Evacuation, or the discharge of the refuse part of the food, through the bowels, is another and the last step in the process of digestion. This part of the subject has a very important bearing on the condition of the health; it is impossible for any one to possess good health, while this office of the bowels is imperfectly performed. If the bowels are relaxed and irritable, the food is borne along too soon and too rapidly; this causes the process of chylification to be imperfect—the chyle is imperfectly formed, and the lacteals have not sufficient time to absorb it from the mass; this prevents the food from nourishing the system. Hence, those who suffer from chronic diarrhoea may eat largely, and yet grow weaker and weaker; their food does not nourish them; the nutritious part passes off through the bowels, instead of being taken into the blood. If the bowels, on the other hand, are constipated, the consequences are no less unhappy. No one can possibly be well with costive bowels; the free and easy action of the bowels is as truly essential to health, as the free circulation of the blood. When the bowels are sluggish, the process of absorption of the chyle is retarded; and what is absorbed, is less pure and healthy, so the quality of the blood is impaired.

Besides the evils already mentioned, a costive state of the bowels often causes a pressure of blood on the brain, and also derangement of the nervous system, excitability of the nerves, nervous headache, depression of spirits, and a long catalogue of sufferings, too numerous for details. Habitual costiveness impairs the tone of the stomach, and prevents its healthy action; piles, also, with various degrees of severity, are often caused, directly or indirectly, by constipated bowels.

The causes of constipation are various, and to point them out in detail would be, perhaps, a fruitless task. But there is one cause, and a very common one, which claims attention here; it is the habit of inattention to, and neglect of, the natural promptings of the bowels to evacuate themselves. Thousands on thousands, especially females, by a habit of checking the natural inclination of the bowels to throw off their contents, have brought upon themselves habitual costiveness, which, in time, has cost them immense suffering and wretchedness. No one should ever hold his bowels in check, if it be possible to avoid it; it can readily be perceived, that doing this would tend to diminish the natural effort of the bowels, and to collect their contents into a solid mass; then, the exertion required to empty the bowels, or the physic taken to aid or make effectual that exertion, tends also to increase the difficulty.

A habit of costiveness should always be removed, if possible; and the best way of doing this, is by a course of discipline. Those articles of food should be selected, which have an influence to keep the bowels open. Bread, made of flour, has a tendency to constipate them; but brown bread, and bread made of wheat meal, have a tendency to open them—also molasses, taken with food, has an additional tendency; fruits and greens, if the stomach can bear them, are adapted to relieve costiveness. The influence of the mind should also be brought to bear upon this difficulty; the operation of the mind on the physical system is very great, especially in chronic complaints.

A person with costive bowels, should have a mental determination to have a natural evacuation of the bowels, at some regular hour in the morning—just after breakfast should be preferred. By a mental calculation, by bearing the subject in mind, by thinking and desiring, by intending to have the bowels move about that hour, very much may be done by way of facilitating such a result. But if, instead of attending to a favorable diet, and of thinking on the subject at the proper time, we treat the difficulty with medicines alone, we do harm rather than good: for the more alteratives we take, the more we increase the trouble; the physic only overcomes the constipation for the time, and afterward leaves the bowels in a more torpid state. Still, rather than endure the consequences of costiveness, it is better to take alteratives, in conjunction with other means, until the difficulty can be removed. When alteratives are used in conjunction with discipline, they should be of the mildest kind. No proper pains should be spared, in overcoming this derangement of nature, till a habitual movement of the bowels once in twenty-four hours, is secured.—Coles, on Health.