In twelve isolated human corneas (cadaver time 2 to 16 hr) stromal thickness could be maintained within 0.50 to 0.66 mm up to 20 hr by the use of an endothelial bathing medium consisting of glutathione-bicarbonate Ringer's solution, HEPES-buffer, and 20% human serum. During the first 3 to 5 hr of perfusion, temperature reversal occurred in all corneas. Wound healing processes were observed in nine corneas throughout the experiments after scraping off a 2.5 mm area of central epithelium, which was kept in a moist saline-saturated atmosphere.