The term “indigestion” frequently is criticised by medical purists. Neither indigestion nor dyspepsia, they say, means anything. The terms are not particular enough. What kind of indigestion is it and what is the cause of it, they want to know?
For our purposes, however, in spite of the purists, indigestion is a sufficiently good word. At least it is comprehensive and understand-able. Indigestion means any disturbance of the digestive system, whether it is discomfort after meals or before meals, or nausea, or vomiting, or bloating, or belching, or constipation, or lack of appetite, or whatever it is.
Why is it so common? Heaven knows how many dyspeptics there are in the world, but heaven alone knows.
The cause probably is partly because the digestive tract is one of the most sensitive portions of the anatomy. It is essentially a long muscular tube and muscular tubes contract and move and writhe around. During its movings and writhings it inevitably produces sensations.
Some of these sensations are regular normal parts of daily life. Appetite, for instance, is a sensation probably caused by a series of contraction waves passing over the stomach. The daily evacuation of the intestines is accompanied by sensations even amounting to griping, caused by contractions of the large intestine.
Compared with such regular and normal thrusts into consciousness, other vital organs such as the lungs and the heart are quiet and unobtrusive. The heart, of course, sometimes causes painin the disease known as angina pectoris. It occasionally makes it beatings known when the pulse is intermittent or very rapidwhen, as we say, there is palpitation. But these symptoms do not occur very frequently, or to many people. The heart has not many sensory nerve fibers coming from it and hence does not obtrude itself on our consciousness much. Ordinarily it goes along doing its work without calling attention to itself. The same, in general, may be said of the lungs, kidneys and glands. But not the digestive system.
Another cause for this is that the digestive tract is the most primitive part of the animal organism. Whatever else an animal does, it has to eat. And the first segmented animals, of which we are the highest type, are practically nothing except a digestive tract and an envelope of muscle and integument. There are, of course, primitive nervous cells and a primitive reproductive system in such animals, but the big fundamental thing is the digestive tube.
Somehow or other, this old foundation tube of animal life, being the most primitive, the nearest to the actual nature of our being, continues to be the first to respond to stimulus of any part of the organism. In any great emotional stress or excitement the digestive tract begins to make itself known. We have “a sinking feeling in the pit of the stomach”; we “turn sick”; we gape. When worry or chronic trouble comes along we can’t eat, we lose our appetite.
We can expect in any illness, therefore, that “indigestion” of some kind will be one of the reflex signs.