In all the diseases enumerated the regulation of the fluid intake remains in the hands of the physician, and many a fight must be waged with the always thirsty patient. In one disorder only, namely, in obesity, does the popular mind recognize the therapeutic value of restricting liquids, and to-day it is one of the unassailable doctrines of lay-medicine that abundant water drinking makes fat and that the restriction of liquids favors a loss of flesh.

Even among physicians the idea that the restriction of liquids, particularly the avoidance of soups and the reduction of water drinking during meals, favors a loss of flesh enjoys widespread popularity.

The recommendation to restrict the liquid intake in order to reduce obesity goes far back, to the days of Plinius Secundus. A detailed account of these ancient regulations, as well as of similar doctrines enunciated by Panaroli, Ettmüller, and in recent years Dancel and Steinbecher, can be found in the excellent historical review compiled by Ebstein (19).

But the chief apostle of this dogma in our own day was Oertel.

Oertel primarily recommended the restriction of liquids from the standpoint of hydrodynamics. The beautiful results obtained from this practice in cardiac disorders encouraged this view, for the restriction of liquids contributes towards sparing the heart, an organ whose strength and resisting powers are always endangered in obesity.

In the course of his therapeutic studies with this method in sufferers with heart disease, Oertel frequently noted a loss of weight, and a reduction in the volume of the body that he did not feel justified in attributing exclusively to the loss of water. As these patients claimed that there was no difference in their appetite nor any decrease in the ingestion of solid food, and as Lorenzen (20) in a report published from Strumpers clinic chronicled similar observations, Oertel assumed that the reduction of liquids did not merely produce a dehydration of the tissues and greater concentration of the blood, but actually an oxydation of the fatty tissues.

The explanation that Oertel advanced for this process seems rather forced to us to-day, in the light of our present knowledge; he claimed that an intimate relationship existed between the blood vessels and the adipose tissue; the formation of this tissue, according to Oertel, occurring always in or around the adventitia of small blood vessels, arteries, veins and the capillaries issuing from them. As soon as the blood vessels became less filled, as a result of the restriction of liquids and the resulting concentration of the blood, "obliteration of blood vessels and anaemia involving large or small areas" supervened; associated with this, he postulated, "complete arrest of the nutrition of adjacent tissues, dissolution and absorption of their elements" occurred. The fat that was absorbed in this way was destroyed by oxydation as soon as a larger quantity of arterial blood was again carried to the tissues, as a result of the relief of stasis, and in this way the energy of the individual cells was restored. So much for the complicated explanation offered by Oertel, an explanation that satisfied no one - neither the physiologist, the anatomist, nor the clinician.

In addition to restricting the total amount of liquids (including the water contained in the different articles of diet), Oertel also recommended separating food and drink; for, he argued, where solid food is taken abundant gastric juice is secreted and in this way the concentration of the blood favored, whereas, on the other hand, the drinking of liquids with meals causes great dilution of the gastric juice, retards gastric digestion and favors the development of dyspepsia.

The so-called Schweninger Reduction Cure that is much spoken of in Germany has adopted particularly this latter prescription of the Oertel method, i. e., the separation of fluid and solid food.

Schweninger (21) says: "Comparative investigations show that dry, small meals produce a reduction of obesity much more rapidly than meals of the same size that consist in part of liquids. This is not easy to explain. I maintain that the fluid necessary to form the digestive secretions is delivered from the circulating tissue-juices with much greater facility when water is taken with meals than without; for this reason we find that a subject living on a dry diet suffers more or less intensely from thirst while eating the solid meal. As soon as the organism is deprived of water in this way and the latter is not replaced at once by drinking, the body must manufacture water from its own fatty tissue; this it does by splitting the fat into simpler molecules, i. e., by self-combustion. As soon as this act of fat-cleavage is finished, i. e., about one hour after eating, small quantities of liquids may gradually be taken." So much for Schweninger. This hypothesis, still more than the ideas advanced by Oertel, contradicts all the facts of physiology that we know to be true to-day.

It is well known that the doctrines of Oertel and of Schweninger enjoy a wide popularity among physicians, and are accepted as true by many members of the medical profession and of the laity. How often do we hear a patient who is undergoing a reduction cure for obesity say, "I am Schweningering." Many factors have contributed to the popularity of Schweninger's method: In the first place, the association of ideas that connected this method with the world-renowned figure of Prince Bismarck, for it is true beyond doubt that Schweninger exercised an influence over the latter greater than any other physician; in the second place, the great facility with which the Schweninger cure could be undertaken, as compared to the great inconveniences and discomforts that had to be undergone when carrying out any o,f the other so-called "reduction cures." In addition, the various dietetic prescriptions that were formulated by such men as Harvey, Banting, Oertel, Ebstein, Hirschfeld, and Kisch were so complicated, the essentials were so obscured by a mass of detail, that the practicing physician, who prescribed his reduction cures from a book, and the patient, too, who often gleaned his information from the same source, were unable to understand all that was expected of them, and, consequently, found it impossible to carry out the reduction cure according to the rules of whatever system they had decided to follow.

How simple, by contrast to these complicated regulations - that have only within recent years been reduced to a concise and clear, common formula (chiefly by von Noorden) - the prescriptions of Oertel, or still more, of Schweninger !

All that was asked of the patients was to omit liquids, in particular soup and water, from the diet (Oertel), and this restriction, moreover, was to be imposed only at certain times (Schweninger); otherwise one could eat and gormandize to one's heart's content. This method was far too tempting not to be tried at once by hundreds and thousands of men and women. Now it happens to be an established fact that occasionally the restriction of liquids (in the sense of Oertel or Schweninger) causes considerable loss of weight and fat without the operation of any other apparent factor. But according to our experience and the experience of most physicians in the course of the last two decades, these cases are great exceptions, that, as we will show below, can be explained in a very simple manner. As a matter of fact the restriction of liquids - notwithstanding the fact that the laity and superficial physicians attribute commanding importance to this measure - constitutes only a very insignificant and unessential part of the Oertel-Schwen-inger method for reducing obesity. Oertel, in addition to restricting liquids, orders a pretty strict dietetic reduction cure - not differing materially from the old Banting cure; Schweninger in his sanatoria submits his patients, in a routine manner, to a very vigorous course of treatment (a scanty and lean diet, massage, gymnastics, etc.), and incidentally also restricts the liquids; the Schweninger course is probably the most rigorous and severe treatment that is administered anywhere, so that one need not be astonished to find that many who undergo this cure emerge from the sanatorium broken in strength and health.

The great popularity that Oertel's and Schweninger's ideas enjoyed among practicians in general, and among the sick, did not by any means extend to scientific circles.

Hirschfeld (23), in his monograph, was one of the first to demonstrate that the influence of water restriction upon the disassimilation of adipose tissue was neither theoretically nor practically proven. Von Noorden (23) arrived at similar conclusions, and in his book "Obesity" clearly outlined the significance of thirsting and the indications for the restriction of liquids in the treatment of obesity. Stadelmann (24) and Rosenfeld (25) more recently also occupied an attitude towards this question that is altogether antagonistic to the doctrines and the methods of Schweninger.

The important objections that have been formulated against Oertel and Schweninger are based in part on theoretical considerations, in part on practical experience. If the criticism of their views has been severe - almost too severe in some instances - one must never forget that the apodietic manner in which Oertel and Schweninger advanced their ideas on the disassimilation of fat in the organism, without advancing any definite proof for the validity of their arguments, was enough to discredit them in the eyes of scientifically thinking critics. If we carefully review, however, the small number of investigations that we possess in regard to metabolic processes in thirsting animals and human subjects, we will find that the claims of the followers of Oertel and Schweninger are by no means altogether absurd. A review of the literature on this subject may be given in the following paragraphs.