The effect of sodium chloride solutions and natural saline waters on the excretion of hydrochloric acid has repeatedly been made the subject of investigation. Larèche found that the acidity of the gastric contents was reduced in a man suffering from a gastric fistula, if sodium chloride was added to the food. Reichmann obtained the same results in healthy subjects and in patients with dilated stomach in whom he removed the stomach contents by aspiration. Jaworski administered pure water, Carlsbad water (Mühlbrunnen), and Kissingen Rakoczy water, to patients after a period of fasting, and then removed the stomach contents after varying periods of time, and he found that Kissingen saline water was more indifferent, as far as the stimulation of the hydrochloric acid secretion was concerned, than pure water. Schüle performed the most exhaustive and the most exact experiments, and found that small doses of sodium chloride (5 grams added to a test breakfast) exercised no effect upon the excretion of hydrochloric acid. Larger doses (16 grams) produced a considerable reduction in the hydrochloric acid excretion, and if still more was given (24 grams) the primary decrease of the secretion of hydrochloric acid was followed by a later increase. The propulsion onward of the food into the bowel (motility) was retarded neither by small nor large doses of sodium chloride.

A number of experiments have also been published on the digestion of albumin in the test-tube, with and without the addition of sodium chloride. Besides, a number of animal experiments have been described.

Of the latter, the most important ones are those reported by M. Bonniger, in a dog with a Pawlow gastric fistula, for they were carried out very carefully, and the technique of these experiments was well-nigh perfect. This investigator introduced milk into the stomach of his dogs through a stomach tube, and added 2.25 per cent. of sodium chloride to the liquid. He found that the secretion of gastric juice was considerably reduced, that the acidity of the stomach contents was slightly reduced, and that no effect was exercised upon the digestive power of the gastric secretion. Bonniger unfortunately extended his investigations to only one human subject. He added 4 grams of sodium chloride to a test breakfast, and found that this addition made no changes in the acidity, digestive power, or motor power of the stomach. If he added 7 grams of sodium chloride, however, the acidity of the stomach contents was distinctly reduced.

These experiments, of course, slightly differ from the administration of saline waters that we give for therapeutic purposes, for it makes a great difference whether we add sodium chloride to the test meal, or whether we order our patients to drink saline waters some time before each meal - the latter, as we know, being the common practice in watering places.

H. Vincent has reported a number of observations in his patients that differ considerably from the results obtained from experimental work. He ordered his patients to eat a constant diet, and on alternate days added much and little sodium chloride to the food. The difference between the salt in the ordinary diet and the salt in the diet to which was added sodium chloride amounted to as much as 12 grams a day. He reported that on a régime containing little sodium chloride gastric hyperchlorhydria developed, and that at the same time the patient suffered from pain in the stomach, and soon began to emaciate. If, on the other hand, the amount of sodium chloride was reduced considerably, the hydrochloric acid secretion was decreased and the body weight increased. Laufer reported similar observations. Personally, we are unable to corroborate the statements made by Vincent. although the results that we have obtained are for the present only preliminary and call for further investigation and elaboration.

It is unnecessary for us to discuss at length other experiments that have been performed in animals and in healthy subjects, for they are all merely an introduction to the clinical experiments that we will discuss. The only true criteria are observations at the bedside, and here we must make the additional postulate that the experimental investigations correspond as nearly as possible to the practical therapeutic measures that are adopted in actual practice. For just as little as we can determine the therapeutic value of a drug from studying its effect on the healthy subject, so little can we determine the therapeutic value of a mineral water from purely experimental investigations in healthy animals and healthy human beings.

Very little has so far been published in regard to the effect of saline mineral waters on sufferers from gastric diseases. L. Wolff administered 5 grams of sodium chloride in a test meal to a few patients suffering from reduced secretion of hydrochloric acid, but was unable to find any increase in the hydrochloric acid secretion; rather a slight lowering of it. He also found a distinct reduction of the gastric acidity in two patients with average production of hydrochloric acid when he administered small quantities of sodium chloride. In the last two cases, however, the subjective symptoms of the patients improved considerably under the administration of salt. Unfortunately, the number of cases studied by Wolff was very small, and they were, moreover, studied for a very short time only. Very definite statements in regard to the effect of sodium chloride in cases of stomach trouble are reported by Boas. Unfortunately, however, this author does not publish his case protocols. In cases of recent gastritis, with reduced production of hydrochloric acid and increased secretion of mucus, he found that the administration of weak saline waters (Kissingen, Homburg, Soden, etc.) produced a marked increase in the production of hydrochloric acid, better chymifaction of the food, and a considerable reduction of the mucus. In older cases the results were less apparent. From these favorable results Boas draws the negative conclusion that saline waters are not suitable for cases of increased hydrochloric acid secretion. He found that this conclusion was corroborated by the practical results he obtained in some cases. In other cases of hyperchlorhydria, again, he found that the patients improved under sodium chloride, without being able to interpret the cause for this improvement.

A number of other authors of note in the field of gastric pathology have published investigations in regard to the effect of sodium chloride on the course of gastric disease, but the material is so scanty that it is hardly worth while to quote from these writers.

A careful study of all the casuistic material that has been published so far shows that there are many discrepancies and disagreements. One fact in particular is striking, namely, that those who worked in the laboratory and who occupied themselves exclusively with physiological investigations invariably reported a decrease in the secretion of hydrochloric acid; whereas, on the other hand, the practicing physicians who reported on the effect of sodium chloride in gastric troubles seem to have given saline waters, particularly in cases in which the secretion of gastric juice was morbidly decreased, and in which they were endeavoring to raise this secretion. Under these circumstances it seemed a grateful task to undertake a systematic study of the effect of saline waters on the hydrochloric acid excretion in patients suffering from increased and decreased production of hydrochloric acid.