SWELLING OF THE RAT RETINA INDUCED BY METABOLIC INHIB ON* BY

pressure may be a causative factor in vaso-obliteration, as observed in the kitten retina following the intravitreal injection of sodium iodoacetate or sodium fluoride. They commented upon the possibility that treatment by such established metabolic inhibitors, by denying the cells the energy they normally derive from carbohydrate catabolism, might lead to a breakdown in the mechanism responsible for regulating cell size. Opie (1949) was the first to observe that certain tissues, after isolation from the rat, imbibed fluid unless they were bathed in solutions which were distinctly hypertonic. This apparent hypertonicity of such cells to their natural environment, could be effectively abolished by certain toxic agents (Opie, 1950). Other workers have since confirmed this phenomenon in tissues such as liver, kidney, spleen, and brain, and have concluded that there is some definite relationship between cell size and the efficiency of the energy metabolism of the cell. Isolated tissues, even in a balanced saline medium, have been observed to swell under a variety of conditions leadin