There remain to be discussed certain therapeutic aspects of the question; above all it is interesting to determine in what disorders the restriction of liquids may be considered a rational procedure. Some of the most important points of this inquiry have already been discussed in the first chapter, so that it will be unnecessary to again argue for the restriction of liquids in certain disorders of the cardio-vascular apparatus, the kidneys, and the stomach.

(a) The Restriction of Liquids in the Treatment of Obesity

The restriction of liquids in obesity must above all be carefully considered; we must see whether one is ever justified in ordering this restriction, notwithstanding the fact that the investigations described in this monograph show conclusively that one can no longer maintain that the restriction of liquids produces an increase in the intensity of oxydative processes and, in particular, in the combustion of fat.

1. The heart, in obese subjects, is always in some danger of overtaxation - less so in strong, muscular individuals than in weakly persons. A certain limited restriction of liquids (making the total liquid-intake during 24 hours about 1500 c. c. - including everything that flows) is advisable, if for no other reason than that it excludes at least one of the influences that may act deleteriously upon the heart. As we know from experience that obese subjects very easily acquire the habit of imbibing large quantities of liquids, it is absolutely essential that the physician should inquire into the amount of fluid-intake in each case; only in this way can he advise some restriction of liquids with a view to exercising an intelligent prophylaxis even before the heart or arteries show any morbid symptoms. This procedure is still more important in cases in which the heart is already weakened. We agree with numerous authors, who have expressed themselves in this sense since Oertel's publications, that signs of a weakened heart-action, e.g., dyspnoea, mild stenocardiac disturbances, irregularity of the pulse, slight degrees of cardiac dilatation, can frequently be favorably influenced, in obese subjects, by a certain amount of water restriction, even though no actual loss of fat occurs.

In the case of fat people the same rules apply, as far as the heart is concerned, as in the case of sufferers from cardiac disorders; and the value of water-restriction in the latter class of patients has been fully discussed in the clinical introduction to this article (see above).

2. In contradistinction to the untenable theories of Oertel and Schweninger, we do not consider the concentration of the blood and tissue-juices to be an important factor in the destruction of body-fat. One good result may, however, occasionally develop from this effect, viz., that sweating decreases when the body-fluids become more concentrated, so that the disagreeable hyperhydrosis of obese subjects is often rapidly and favorably influenced by careful and persistent restriction of the liquid-intake.

3. We know from experimental and clinical experience that precisely in the beginning of a course of thirsting relatively much water is eliminated from the body. The great losses of weight, amounting to several kilograms, that are often seen during the first week of a reduction cure with restriction of liquids, are usually attributable to the loss of water. From a psychological point of view, as von Noorden (23) has emphasized, this large initial decrease in weight is an important factor. It gains at once the confidence of the patients, who have often sought in vain to decrease their flesh by following other plans; if the patients find that they begin to lose flesh after a few short days of this régime, they are naturally much more willing to cheerfully and energetically undergo the necessary privations that are to follow. The physician should never forget, however, that the loss of weight obtained in this way is not due to loss of fat, but to loss of water.

4. The effect of the restriction of liquids upon the appetite is of the greatest importance. In this case the reduction in the total liquid-intake is less important than the withdrawal of liquids during meals. The effect of the latter regulation, as von Noorden (23) has shown in several cases, varies greatly in dif ferent subjects. Some people are not influenced at all by stopping water-drinking during meals, and eat as much and with the same relish as before; some even develop a greater appetite and eat more. Under these circumstances no loss of flesh can, of course, be expected. Others, in the beginning, suffer some loss of appetite and lose a little flesh, but they soon become accustomed to the new order of living, so that no appreciable effect upon assimilation and catabolism is produced. Von Noorden, in his monograph, quoted a number of cases of this kind, and we have, in the meantime, amplified and corroborated his findings; many physicians, moreover, know from their own experience that nothing permanent is attained in many obese subjects by the restriction of liquids. On the other hand, there are many persons - both healthy and sick - who always eat less when the fluid-intake is reduced, and who sooner or later lose flesh on this régime. Habit plays a large role in these cases. It is probably more than mere coincidence that both Oertel and Schweninger, in their first observations, that are beyond reproach and fully authenticated, encountered only subjects who invariably began to lose flesh as soon as the liquids were restricted, and, above all, when the drinking of water during meals was prohibited. Both these authors, as well as Lorenzen, collected their material in Bavaria, a country in which, from time immemorial, very much more fluid (beer) is taken during meals than in any other country in the world. That solid food could be taken without drinking was something altogether new, something they were not accustomed to, and that many of the patients of the above-named authors considered unnatural; consequently one need not be surprised to find that they voluntarily ate less solid food as soon as drinking during meals was interdicted. However that may have been, the fact remains that many persons eat considerably less when they are not allowed to drink ad libitum at the same time. In our own experience we have seen this effect of thirsting especially in children, in heart cases, in sufferers from renal diseases, and by no means least pronounced in obese subjects, especially in that form of obesity that has been symptomatically designated by the name of "plethoric obesity." In patients with so-called "anaemic obesity" a spontaneous craving for abundant liquid is on the other hand frequently absent, and the restriction of liquids by order of the physician generally exercises no effect upon the amount of solid food ingested, nor does it cause a loss of fat.

We see, therefore, that the restriction of liquids is a therapeutic weapon in reduction cures that sometimes is dull and treacherous and at other times sharp and effective. A physician who has enjoyed much experience in such cases will in the majority of instances be able to predict correctly whether or not this weapon will be useful and successful; but even the most experienced practician may be misled, and he, too, like the inexperienced, is forced to carefully study each individual case before he can decide whether the restriction of liquids is going to bring about the desired result or whether it is going to be without effect.

Unless forced to do so by special reasons (see above, 1-3) we do not employ the restriction of liquids extensively in our clinic - following in this respect the ideas enunciated by von Noorden in previous publications; nevertheless the therapeutic results we obtain in obesity are as good and as uniform, if not more so, than those obtained anywhere else.

When the heart is to be considered (see above), it is true, we do not permit more than 3/2 liters of liquids. This includes everything that flows, whereas the water contained in solid articles of diet is not considered. Only if large quantities of fresh fruit are given, that consists of about 90 per cent, of water, do we reduce the liquids still more. It is hardly necessary, however, to particularly order this further restriction, because the patients of their own account reduce the amount of beverages when they eat much fruit. If the restriction of liquids is carried no farther (maximum permitted = 3/2 liters), and if attention is chiefly given to a regulation of the caloric values of the solid ingesta, then results are seen in reduction cures for obesity, that yield a gradual loss of flesh without any feeling of discomfort or deprivation on the part of the patient; the reduction in the weight of cases treated in this way is not very rapid, but it is sure to occur gradually. In the average case the further restriction of liquids is, to say the least, superfluous; if it is imposed at all it should not be done because it is customary to do so, or because certain routine methods of treatment require it, but because definite indications for this practice are found to exist. Otherwise the patients are subjected to unnecessary torture.