There are two forms of acid dyspepsia. In one the normal acid of the gastric juice (hydrochloric acid) is in excess ; in the other various organic acids present in the food or arising from fermentation give rise to acidity of the stomach and other symptoms of dyspepsia. These cases usually only come under treatment when the dyspepsia has lasted a long time, and is more or less chronic. To find out what is the exact nature of the trouble the physician should prescribe a test meal, the contents of the stomach being afterwards removed by a stomach tube and analysed. One of the meals commonly used for this purpose consists of a roll or 2 ounces of stale white bread and a breakfastcupful of weak tea or hot water. The meal is taken early in the morning, and the contents of the stomach drawn off about an hour afterwards, that is to say, when the digestion is at a height. The material is filtered, and reagents, which reveal the amount and kind of acid, are added to it.

If the condition of the stomach were normal these test meals and the subsequent analysis would be unnecessary. The acidity of the gastric contents would be normal. The consumption of food would be a pleasant and agreeable task, followed by a sensation of comfort and well-being. But such an examination being called for proves the existence of some abnormality.

Where the analysis shows that the hydrochloric acid of the gastric juice is in excess, the abnormality is what is known as Hyperchlorhydria. The gastric juice is too free and too strongs the secretion begins too soon after the meal and is excessive. In the normal condition, saliva is mixed with the food during mastication and continues to act on it after it reaches the stomach. Fully half an hour elapses after the food is swallowed before the secretion of the stomach is sufficiently acid to check the action of saliva. But in the condition of hyperchlorhydria free acid appears about ten minutes after beginning to eat, and the digestion of starch in the stomach is thereby prevented. This abnormal condition occurs in about half the people, between the ages of twenty and forty-five years, who suffer from indigestion. It is the condition which occurs in the student working hard for an examination, in the man who applies himself strenuously to business, the hard-working clerk, lawyer, accountant, or busy shopkeeper. But it is not merely strenuous application to duty which causes the trouble. It may be brought on by grief, worry, and anxiety; by gobbling the food without proper mastication; hurrying from business to meals and meals to business; it may be due to the local irritation caused by acid foods, heating spices and condiments, excess of alcohol and abuse of tobacco, and sometimes by other gastric diseases. Summed up briefly, the cause of hyperacidity is an irritation of the gastric mucous membrane, and its technical sign is the discovery of an excess of hydrochloric acid in the gastric contents at the height of digestion.

In such persons the digestion of protein foods (meat, fowl, fish, milk, etc.) is perfect, and their presence in the stomach relieves the symptoms by taking up the excess of acid as it is secreted. But starch and all foods containing it (bread, cakes, puddings, etc.) are not digested so easily as usual, and their detention in the stomach is often delayed, especially when the acidity gives rise to spasm of the pylorus or aperture of exit. As a general rule there is perfect comfort for about an hour after the meal, then the characteristic symptoms begin, viz., discomfort, heartburn, nausea, giddiness, and palpitation or a sense of oppression, which are only relieved by the eructation of gas, drinking some fluid which dilutes the acid gastric juice, or the consumption of another meal.

The dietetic treatment of such cases varies. Where the acidity has been called forth by the regular consumption of an excess of meat, fish, fowl, etc., the excessive secretion is a means to an end. But hyperacidity also occurs in people who eat little meat, and, therefore, the proportion of acid is only relatively high, that is to say, the acid is secreted but it has not got the right kind of food to work upon. In either case, the disorder is fostered by hurried eating, imperfect mastication, and wrong diet. Therefore the first thing to do is to regulate the habits as regards the kind and amount of food, care in its mastication, and regularity in the hours at which the meals are taken. These rules are applicable to all dyspeptics.

Authorities differ as to the kind of food such patients should be allowed. There is no doubt that a profuse secretion of gastric juice is provoked by an excess of meat, soups, meat extracts, and so forth; and fat has a retarding influence on the secretion, and especially on the amount of acid; while bread and other starchy foods provoke only a slight secretion of gastric juice. But the patient has to be considered individually. If the disorder occurs in one who has hitherto consumed little animal food, it would be better to reduce the amount of bread and other starchy foods to a minimum and increase the intake of meat, fish, milk and eggs as much as possible, to give the gastric secretion more substance to work upon. Of course, it will be necessary for these foods to be in an easily digestible form, and unaccompanied by vegetables, such as cabbage, turnips, swedes, and raw salads.

On the other hand, there are some cases where the animal food should be restricted. These are people who have been acustomed to eat a lot of meat, fish, and eggs. There is no doubt that these foods speedily absorb the gastric juice and prevent or diminish pain or irritation. But it is plain enough that if such foods continue to be taken in excess the supernormal secretion of gastric juice will be encouraged. Nature continues to respond to the demands made upon her for hydrochloric acid so long as she can do so. But the continued call for acid to combine with the animal foods which are constantly taken may tend to hypertrophy of the glandular elements of the mucous membrane, and to their ultimate exhaustion and inability to respond (hypochlorhydria), whence the last state of the patient may be worse than the first. Therefore no general rule of treatment can be established. Each case must be treated on its merits, and each article of the diet must be selected by reference to the present condition or the former habits of the patient.