As the name suggests, this condition is characterized by a diminution of the hydrochloric acid and is likely to occur as a sequel to the condition just described. As the hydrochloric acid is an essential in gastric digestion of proteins, its diminution decreases the quantity of proteins possible for the stomach to digest. On the other hand, the presence of proteins serves as a stimulus to gastric secretion, and they should not be markedly diminished in the diet. However, in this condition, more than in the preceding, the interval between meals should be sufficiently extended to insure not only the digestion of foods and their passage from the stomach into the duodenum, but also a period of rest for the stomach. Some physicians hold to the advisability of assisting the stomach by administering hydrochloric acid. "When this is done it should always be administered not earlier than one hour after the meal. If it is administered with the meal its presence in the stomach will have an inhibitory action on gastric secretion. For similar reasons, any fruit acids, as lemonade or egg lemonade, taken at or near the mealtime, should always be at the end of the meal, or, better yet, half an hour or an hour after the meal.

Achlorhydria, characterized by the entire absence of hydrochloric acid, makes it quite out of the question for the stomach to bring about the digestion of proteins. When we remember that there is a provision for the digestion of proteins in the duodenum through the trypsin of the pancreatic juice, it becomes evident that if we can so control the conditions as to cause a passing of the food through the stomach into the intestines, it will be digested there. This can only be accomplished by ingesting into the stomach liquid foods which remain liquid in the stomach. If milk were ingested the rennin of the gastric juice would coagulate it, but it could not be digested on account of lack of the hydrochloric acid to initiate the process on the coagulated casein, so unmodified milk is distinctly contraindicated in achlorhydria. Peptonated milk may serve as one article of diet; gelatin, cream, butter, bacon, olive oil, all may pass through the stomach without change and are digested in the small intestine. Carbohydrates, especially cereals, cooked to the point of liquefaction may pass through the stomach with practically no change and be completely and easily digested and absorbed in the small intestine. Such carbohydrate foods as zwieback or buttered toast may also be used, but the precaution must be positively observed of masticating these foods until they are absolutely liquefied into a smooth liquid in which one is not conscious of any solid particles. When thus liquefied these foods may pass readily through the stomach without causing irritation, and be completely digested in the small intestine.

In several of the foods above mentioned - viz., the cream, gelatin, and the cereal - there is a certain amount of undigested though liquefied protein. The presence of this protein in the stomach will serve as a mild stimulus to the gastric glands, and it is perhaps through this stimulus, as much as from any other cause, that the secretion of the acid is begun again by these glands.