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December 31, 1927


JAMA. 1927;89(27):2265. doi:10.1001/jama.1927.02690270031011

Among the various possibilities that have been held responsible for the genesis of urticarias or urticarial edemas, the indefinable factor described as altered permeability of the capillaries must be included. It is conceivable that such an alteration in the blood vessel walls may be brought about through the influence of chemical changes in the medium that normally bathes them as well as by the sudden appearance of foreign chemical substances, for example, toxins of bacterial origin, anaphylactic products, or extraneous poisons. Biologists have demonstrated on the simpler physiologic "models" of the lower forms of life that the permeability of their membranes is influenced by the relative concentration of potassium and calcium, among other agencies. Increases in the alkali elements bring about greater penetrability; decreased permeability may result from a lack of calcium. Hamburger,1 for example, has shown that artificial edema may be produced by perfusing tissues with solutions deficient