FOUR FIGURES
Injury potentials of striated muscle tissue are of considerable theoretical interest. The striated portion of the adductor muscle of the common scallop (Pecten gibbus) offers a particularly favorable material for studies on the nature of the mechanism or mechanisms giving rise to such potential differences. I have already described a series of reactions, occurring at the injured surfaces of such muscles, which control the magnitude of the measured injury potentials (Steinbach, '33 b). I n order to gain further insight into the nature of the surfaces or membranes involved, the present series of experiments on diffusion or concentration potentials was undertaken.
Injury potentials are of considerably higher magnitude than the potential differences which originate in the simple diffusion of ordinary electrolytes, at least within the concentration ranges which might exist in living systems. I n order to explain these high potential differences the selectively permeable artificial membrane has been used extensively as a model system. This model is too well known to require further discussion. The papers by Michaelis ( '25) and his collaborators may be consulted for a consideration of the practical and theoretical aspects of the model and its application to biological systems. This paper will present evidence showing that this model will not account for the potential changes observed National Research Council Fellow in the Biological Sciences.