Notes on Fischer's theory of the influence of acids in the production of edema. 1

Several years ago Gies published some of the results of a preliminary study of the effects of acids on tendon collagen. 2 Last December Kantor and Gies reported their observation that collagen fibers from tendon immediately swell markedly in free acid but do not swell at all in any strength of combined acid 3 —facts on which they base a new microscopic test for free acid. These results naturally led Kantor and Gies to consider the relation of such facts to Fischer's theory of edema, which they were investigating at the time these observations were made. Lately we have gone into this particular phase of the matter with some experiments on fibrin. Similar experiments are under way with other colloids and with various tissues.

Fischer's general conclusion in regard to edema is stated in the following terms : 4

“A state of edema is induced whenever, in the presence of an adequate supply of water, the affinity of the colloids of the tissues for water in increased above that which we are pleased to call normal. The accumulation of acids within the tissues, brought about either through their abnormal production, or through the inadequate removal of such as some consider normally produced in the tissues, is chiefly responsible for this increase in the affinity of the colloids for water, though the possibility of explaining at least some of the increased afinity for water through the production or accumulation of substances which affect the colloids in a way similar to acids or through the conversion of colloids having but little afinity for water into such as have a greater afinity must also be borne in mind.” 1