Numerous investigators have observed that the excised cornea respires and that glycolysis takes place in both aerobic and anaerobic conditions. In particular, Kohra (1935), Fischer (1940) and deRoetth (1951) observed that in the absence of oxygen the rate of glycolysis increased in all corneal layersthe epithelium, the stroma and the endothelium. Further, they demonstrated that the collagenous stroma, comprising nine-tenths of the corneal mass, possessed a very low metabolic activity compared to the outer cellular layers. Kohra studied rabbits, deRoetth cattle, while Fischer did not state the species employed. All these authors used a manometric technique to determine glycolytic rates, and deRoetth in addition made simultaneous analyses of the rate of accumulation of lactic acid in the cornea using a chemical technique. His findings differed from earlier workers in one important respect in that he observed no glycolysis or lactic acid accumulation in the epithelium in the presence of oxygen.An absence of lactic acid production in the epithelium in aerobic conditions is not readily reconciled with the observation that lactic acid exists in this layer in a concentration exceeding that in the stroma both in bovine and rabbit cornea (Herrman & Hickman, 1948;Langham, 1952). In an attempt to elucidate this problem the rate of glycolysis in the whole excised cornea of the rabbit has been determined and related to the rate of accumulation of lactic acid in aerobic and anaerobic conditions, and to the rate of glycolysis in the component layers determined by a manometric technique.The supply of oxygen to the cornea presents special problems, and it is still uncertain whether the tissue can obtain sufficient to respire at a maximal rate. In an earlier investigation (Langham, 1952) it was observed that the concentration of lactic acid in the cornea of the rabbit decreased when the atmospheric oxygen tension was raised. The possibility that this may reflect a change in the rate of accumulation of lactic acid has now been investigated by comparing the rates at which lactic acid accumulates in the cornea of the living animal and in the excised tissue.
