SINCE the greater part of the cornea is remotely situated from the blood stream, this area may present unique mechanisms for the transfer of metabolites and excretory products. This tissue is avascular, but it is surrounded at its periphery by intravascular and extravascular fluid. Furthermore, it is bathed anteriorly and posteriorly with continuously circulating fluids. It is exposed to the atmosphere in the waking hours and yet survives many hours when sealed by the lids during sleep. Even the relatively anaerobic environment in the conjunctival sac of deep-sea-diving mammals and hibernating land forms does not irreversibly disturb the functions of the cornea. It is pertinent, therefore, to inquire: How does the cornea respire? Are its cellular metabolic mechanisms similar to those found in other tissues? If not, in what way do they differ? This report is an attempt to outline the experimental investigation which has been undertaken on these problems,