INDIGESTION ITS CAUSES AND CURE by JOHN. H. CLARKE.
THE process of digestion commences immediately as the food is taken into the mouth. Before food can be converted into blood, it is necessary that it be reduced to a liquid or semi-liquid state. All solid foods, therefore, must be broken down in the first instance to fine particles, and for this purpose the teeth are provided. Solids may be swallowed unmasticated, it is true, and the strong digestive juices are capable of digesting them, but this power is made much more certain and easy if the food has been first finely ground by the teeth. But the teeth have another function. In the cheeks and under the tongue are the salivary glands and the ducts of which convey the saliva into the mouth, and one function of the teeth is to mix the food thoroughly with saliva at the same time that they grind it small. The leading action of the saliva is on the starchy elements of the food, which are converted by it from insoluble starch into soluble grape-sugar. In this way solid food is prepared for its passage into the stomach, which is the organ of digestion par excellence.
The stomach may be defined as an organ for the reception, at proper intervals, of food and water. I say “water,” rather than “drink,” because whatever drink is taken, it is the water which is the essential thirst-quenching part of it. The stomach, when it has received the food, does not complete the digestion of it, as many people imagine, but it does by far the largest share of the work in liquefying the food and reducing it to a condition in which it can be absorbed. It is lined with a mucous membrane richly supplied with glands of a special kind, which secrete a very powerful acid fluid. This fluid acts chemically on the food taken, breaking it up and reducing it to a pulp. It also contains the substance “pepsin,” which acts in a peculiar way like a ferment, converting all the albuminous foods, such as meats of all kinds, into “peptones” which can be absorbed, in the same way that saliva converts starch into grape-sugar. Besides the mucous coat there is a muscular coat, with fibres running in two directions–from end to end, length ways of the organ, and circularly, all round it. By these two sets of fibres the food is moved about when the stomach is full, until it has all come in contact with the mucous membrane and been submitted to the action of the gastric juice. When thoroughly mixed with this, the whole being reduced to a grey, semi-fluid mass, it is ready to be passed on into the bowels. There it meets with the bile, the pancreatic juice, and the secretions of the intestinal glands and mucous membrane; and as each different secretion acts on it, some portion of it is rendered ready to be taken up by the absorbent vessels called lacteals which abound in the intestines. In the lacteals it is a fluid and looks like milk. After passing through the abdominal glands, where it under goes some further preparation, the fluid is at last collected from all the lacteals into one large duct (the thoracic duct) and poured into the current of the blood.
This is the primary digestion, and that alone with which I concern myself in the present treatise; but there is also a secondary digestion, to which I will briefly refer. All the tissues of the body are in a state of ebb and flow. Where life is there is no standing still; everything is in a state of motion and change. The tissues once built up from the food no sooner reach their perfection and perform their function than they begin to decay and make room for more. Some tissues change more rapidly than others–the soft tissues more rapidly than the hard, but all change and break down into their elements. The secondary digestion consists in the absorption of these decomposed elements by the lymphatic vessels and glands, the elimination of those elements which are entirely waste, and the recomposition of those that are still utilisable into blood and new tissues.
This process is one of vast importance, and one which is easily deranged. Some people naturally have a more active secondary digestion than others, and these are generally thin. Tissue-change goes on rapidly, and it matters little how much they eat, they can never fatten. In spite of their spareness they have generally great vital heat, and are of an active, nervous, and restless temperament. Others, on the contrary, eat little, but grow constantly fat. With them the process is slow; the tissues burn away (for it is essentially a burning process) less rapidly, and they are of a quieter, more easy-going disposition-lymphatic or phlegmatic. But when there is not merely slow tissue-change, but, in addition to this, a defect in the carrying off of the effete matters from the tissues, then we have various kinds of diseases arising as the effete matters accumulate in the system. If it is lactic acid, we have rheumatism; if the predominating substance is uric acid, we have gout. These are, in general, diseases of the secondary digestion. It is, of course, possible, and, indeed, most common, to have defects of the two digestions combined, but they are distinct things nevertheless.
I have said that the secondary digestion is easily interfered with. All lowering influences put a check on it. Too great exposure to cold, for instance, will stop it, as in the chill which sets up rheumatic fever. Alcohol, tea, coffee, opium, tobacco, check it; hence some of the diseases that spring from over-indulgence in these as articles of ordinary consumption. Of course, it will be easily understood that the two digestions act and react on each other; and it must not be forgotten that the above-mentioned substances powerfully affect the primary digestion, and may disorder that as well as the secondary.
Having explained this much, I will return to a consideration of the stomach, for that is the organ which is chiefly concerned with what is popularly understood by “indigestion” and is, in fact, the most important of the digestive organs. If the stomach is in good condition, the chances are that the rest of the organs of digestion are in good condition also, and if these are not sound, the stomach is pretty sure to feel it, and let its owner know.