The most important part of digestion takes place in the stomach. Here the food is thoroughly triturated by the movements of the muscular walls of the stomach, and mixed with the mucus and gastric juice poured out from the glands of the stomach; the albuminoids are acted upon by the pepsine, and absorbed by the veins of the stomach in the form of albumose. The most frequent cause of stomachal indigestion is chronic gastritis. In this malady the mucous membrane of the stomach is subject to frequent attacks of subacute inflammation, with the result that the peptic glands become atrophied, their cells are degenerated, while the mucous glands become hyper-trophied. The consequence is that the gastric juice is deficient in quantity and poor in quality, while mucus is secreted in excess. When this malady is once firmly established, it is very difficult, if not impossible, to cure. The mucous membrane of the stomach may be, however, in a condition anatomically healthy; in this case the indigestion may be caused by irregular nervous action, or by an unhealthy condition of the blood. The gastric juice may then be secreted in excess, giving rise to "acidity," or it may on the other hand be secreted insufficiently, causing slow and difficult digestion of the albuminoids. The gastric juice may also contain either too little or too much acid. In the first case, the pepsine is slow and uncertain in action; in the second, digestion may be too rapid. These irregularities, in the secretion and condition of the gastric juice, may be due to the want of proper nervous control of the minute blood vessels which feed the peptic glands, or to abnormal conditions of the blood, as in fevers, anaemia, diabetes, etc. Stomachal indigestion may be also caused by slow, sluggish movements of the muscular walls of the stomach, or by too rapid and energetic movements which cause the food to be ejected into the duodenum before it is thoroughly broken up and submitted to the action of the gastric juice.

Fig. 9. - The Gastric Glands of Man.

A. Peptic gland of the middle part of the stomach. 1. Its excretory duct. 2, 2, 2. Its three principal branches. 3, 3, 3. Its secondary divisions, in the course of which are numerous culs-de-sac all of which are filled with spherical cells.

B. Peptic gland of the splenic end of the stomach. 1. Its extremely short duct. 2, 2. Its two principal branches. 3, 3. Numerous culs-de-sac in which they terminate.

C. Mucous gland of the pyloric end of the stomach. 1. Its duct. 2, 2. Its two main divisions. 3, 3, 3. Its secondary divisions. 4, 4. Small racemose glands at their termination.

Fig. 10. - Gastric Glands of Man in a Morbid Condition.

A. Atrophied peptic gland containing no longer spherical cells, but only a small quantity of fluid. 1. Its duct. 2, 2. Its branches, the calibre of which is reduced, and the outline very irregular, the culs-de-sac hollowed along its course have almost entirely disappeared, and are only represented by very small swellings of uncertain form.

B. Another peptic gland from the splenic region, of which the duct, branches and culs-de-sac are on the contrary dilated. 1. Free end of the duct which is not dilated. 2. Lower end of the same dilated like a bottle. 3, 3. Its branches slightly dilated. 4, 4. Terminal culs-de-sac filled with fluid and inclined to be cystic.

C. Peptic glands the divisions of which are atrophied; three of these divisions terminate in actual cysts. 1. Duct of the gland. 2, 2, 2. Its different branches. 3, 3. Dependent cysts.

D. Cysts of various diameters which float here and there in the fluid of preparation, and which were wrongly considered by anatomists to be closed follicles. 1. Cyst detached from the gland to which it belongs, carrying with it a part of its pedicle. 2, 3, 4. Other smaller cysts, the pedicles of which have been broken off at the point of insertion.

It will be seen from the foregoing that the causes of indigestion in the stomach are many and various, hence the extreme difficulty of treating this complaint on any well-defined rule. The symptoms may be the same, but the causes are different, and the disease must consequently be differently treated. In one case alkalies are indicated; in another, hydrochloric acid gives relief: in one, food must be taken at frequent intervals; in another, long periods of rest must be given: in one, fluid food can alone be borne; in another, the meals must be taken without drinking. The stomach has, moreover, many idiosyncrasies and antipathies which are either constitutional and permanent, or functional and temporary. Thus one person cannot digest strawberries, another cannot take onions; one person cannot eat shellfish, and to another mushrooms will give an attack of indigestion. The dietetic treatment of stomachal dyspepsia can therefore be only correctly arrived at by experiment based on certain well-known principles; in fact, each dyspeptic must discover for himself what he can eat, how much, and how often.