Some twelve years ago we undertook a systematic study of the effect of saline mineral waters (that is, mineral waters containing sodium chloride) on different pathological conditions. At the time when these investigations were begun, our only knowledge in regard to the therapeutic effects of these and many other mineral waters was purely empirical. When one desired to know more than the simple fact that this or that mineral water was useful in this or that disease, to know the why and wherefore of the therapeutic effect of the different waters, and to know the influence of the different waters on normal function and on perverted function, it was found that our knowledge was altogether inadequate to answer any of these inquiries. Here and there an animal experiment was reported, from which certain conclusions in regard to the above uncertain points were drawn. Here and there certain clinicians reported experiments on healthy human subjects, but no one up to that time had made any clinical and experimental studies on sick people. This state of affairs was peculiar because, during the years immediately preceding this period, the study of the pathology of metabolism and the therapeutic correction of perverted metabolism had been followed with much interest and enthusiasm. It had also been known, ever since the days of antiquity, that mineral waters in particular were capable of exercising an influence upon the metabolism of human beings.

As a matter of fact, many investigations were published in former years in regard to the influence of mineral waters on metabolism. Unfortunately, however, most of the time and labor had been expended in elucidating one point in particular, namely, the effect of these waters on proteid metabolism, and these studies were especially fruitless. Any clinician, however, who sought practical and therapeutic information in the older writings was confronted with nothing but wild hypotheses. We will have occasion to show in the following pages how little positive knowledge had been acquired up to the time when our investigations were begun.

We undertook to amplify our knowledge in this field by a series of clinical and experimental investigations. Particular attention was given to inquiries that commanded practical interest. Such questions were chiefly those that were concerned with the effect of saline waters on digestion and on the arrangement of the diet while a drinking cure was being instituted. The latter investigation in particular seemed desirable, because in many watering places, like Kissingen, Carlsbad, Homburg, etc., dietetic regulations were given to the patients by routine, and these dietetic regulations were justified only by custom. In the light of more modern scientific studies on the processes of nutrition, these routine dietaries were certainly irrational and could readily jeopardize the reputation of the particular watering-place in which they were customarily prescribed.