1899 Journal of the American Medical Association (JAMA)  
The history of the theory of edema shows a striking similarity to the development of the theory concerning secretion and absorption. The latter theory, however, has gained a firmer basis at an earlier time, and the research pertaining to secretion and absorption has shown the way to that concerning edema. The two theories traveled almost identic paths until, through the work of Ludwig and Haidenhain, the theory of secretion and absorption reached pretty firm ground, leaving the solution of the
more » ... uestion regarding the production of edema in the rear. Much less good work has been done on the theory of edema during the time following the publication of Cohnheim's first investigation in 1877. Indeed, the theory of edema has been a neglected problem, if we may judge by the few papers which have been published on this subject during the last six years. Still, within the last months, the theory has taken an important forward step through the work of Professor Loeb of the University of Chicago. At last, a firm physical and chemic basis has been given to the theory. In secretion and absorption as well as in edema, solutions of organic and», inorganic substances pass through animal membrane. To determine the driving force, has been, and is today, one of the greatest problems of physiology. Secretion and absorption took a decided step toward their solution when philosophic explanations-a speculative basis-were cast aside and rigid physical and chemic investigations were instituted which promised better results. Capillary pressure and filtration seemed then sufficient to explain the phenomena. A new area appeared after the investigations of C. Ludwig. His researches on the secretion of saliva put the driving-force not outside of the cell membrane, but inside of it, and showed that those complex units of the body, the cells, are not passively but actively engaged in the secretion of saliva. Of equal importance is Haidenhain's work on absorption and on the flow of lymph. Even lymph flow, seemingly the most simple case of the passing of fluid through animal membrane, can not be explained upon the basis of filtration and diffusion alone. Much time could have been saved to the theory of secretion, if comparative physiology had been taken into consideration. Even in animals, insects, for instance, where blood-pressure is at a minimum, secretion is well marked. If physiology had not ignored the facts of comparative physiology, filtration and diffusion could not have been considered as explanations of secretion or allied processes. Finally, we are forced to acknowledge "vitalismus," or the "vital force" of the cell. We may call it that, provided we bear in mind that this term has lost all of its metaphysic meaning, and that by it we mean only peculiar chemic and physical properties of the cell. Of course, we must acknowledge that the chemistry and the anatomy of the cell are only in their infancy today. Let us call to mind here the illustration of the steamship, with which Haidenhain opens his classic paper on intestinal absorption. As soon as we will have passed the difficulties which Haidenhain enumerates, we will be enabled to look more clearly into this matter, and a complete solution of the problems of secretion, absorption, and allied processes will be the consequence. In 1827, Richard Bright showed beyond doubt that the presence of albumin in the urine pointed to a diseased kidney. According to him, edema finds its origin in blood poor in albumin. The "thinned" blood reaches the tissues by filtration, while the normal blood is too thick to pass through the vessel wall. Although this theory retained its place for the next fifty years, modifications of it were put forth as a consequence of observations. Albuminuria, for instance, exists without kidney lesions. Albuminuria, as found in scarlet fever and diphtheria, shows another fact. Although, in these diseases, the urine often contains a large amount of albumin, edema at the same timé being very extensive, nevertheless, the urine is discharged in such small quantities that the extent of the edema and the discharge of albumin are not at all proportional. Again, in some lesions of the kidney, the discharge of albumin may go on for years, the quantity of urine be large, and yet edema may never complicate matters at all, or at least not until the final stage of the disease has been reached. These facts modified the original explanation of Bright, so that the loss of albumin was not supposed to be the cause of edema, but only a favorable factor for an easy transudation of the fluid constituent of the blood. The principal cause of edema was supposed to lie in the retention of water in the blood, which even led to a thinned condition of the serum, and increased the amount of other fluids of the body.1 Filtration, therefore, played the principal part in the transudation process. It is undoubtedly true that the amount of urine is increased, if large amounts of fluids are taken into the body. It is also known that during edema, the urine is diminished, while again, during the absorption of the edematous fluid, the urine increases in quantity. This phenomenon takes place during inflammatory processes also. Might it not be true that the urine-quantity depends upon the transfusion of fluids, and not vice versa? These are two entirely different conditions. All the complicating facts and suggestions originating from Bright's theory about the dependence of edema upon the quantity of albumin in the blood, 1 Bartels: Ziemssen's Handbuch d. spec. Path. und Therapie, x, 1. 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doi:10.1001/jama.1899.92450290001001 fatcat:aoprfc5cdrbadhdbl56depf3gi