Having now determined that the indigestion is not secondary to some chronic constitutional disease, and further, that it is not dependent, so far as can be ascertained, on organic disease of the stomach or other organ, we now conclude that it is of "functional" origin. By that we mean that it depends, not on any demonstrable standard change, but on some alteration in the secretions of the gastric or intestinal juice, or in the muscle of the stomach wall, of a nature not yet fully understood. Thus the gastric secretion may be increased in amount or reduced below the normal. When it is increased we have the condition of hyperchlorhydria, which is probably the only type of "functional indigestion" which admits of accurate differentiation. The symptoms of this hyperchlorhydria are quite distinctive, and are the subject of special consideration on p. 326. This hyperchlorhydria is often associated with motor insufficiency of the stomach wall, revealed by a state of dilatation of the stomach, hence the inclusion of this in the organic group above described. There remains a very large group of cases which hardly admit, in our present knowledge, of more accurate classification than that of functional dyspepsia or indigestion. The causation of these will soon be shortly considered, the existing cause in the majority of cases being dietetic errors.

ItHperfect mastication, defective state of the teeth, hurried irregular meals of an ill-balanced nature, and constipation are probably the most important causal factors. By their action, singly or in combination, the digestive functions are seriously impaired, with the resulting clinical features characteristic of indigestion. Among the dietetic errors which are frequently responsible, mention may be made of excessive tea-drinking, immoderate use of starchy foods, over-indulgence in sweets, and occasionally excess of meat foods. Excess of tea, excess of sweets, and too great use of starchy foods is more frequently the cause of the indigestion seen in young women; in men, excess of tea, or of meat, or of starchy foods is also responsible, and their unfavourable action is in them often intensified by over-indulgence in tobacco or alcohol. Reference should be made to the value of the careful examination of the urine as an aid in diagnosis in certain cases of indigestion. In cases in which the urine gives a marked pancreatic reaction, the indication is to restrict to a marked degree the farinaceous and saccharine foods.

It must be clearly recognised that there are cases of functional indigestion which are not dependent on any dietetic error, but are the result of a temporary lowering of the general nervous tone of the individual. Such cases are cured by measures directed to the improvement of general health, without special reference to dietetic conditions; such measures as rest, change of air, and general tonic treatment alone sufficing to get rid of the indigestion. In the treatment of the general run of cases it is essential to point out that complete rest in bed for a week or two or longer, and attention to the bowels, are points of cardinal importance in the treatment. Clinical experience shows that not a few cases which have been diagnosed, after full consideration, as cases of functional indigestion, are really cases of organic disease. In some respects this is not a matter of great moment, as in cases of doubt the dietetic treatment of the two conditions is essentially the same.