Alkali burns were produced in one eye of a group of mice. Two, 3 and 4 weeks later the second eye of each mouse was similarly burned. The rate of perforation in the second-burned eyes was significantly higher than in the first eye. This effect was abolished by immunosuppressing the animals before the burning of the first eyes. This potentiation effect of an ocular burn on subsequent ones is transferable to other mice by intraperitoneal administration of convalescent serum prepared from mice that were previously burned. This evidence suggests that ocular alkali burns cause the appearance in the circulation of antigens not previously present there. The antibodies produced against these antigens exacerbate the subsequent burn lesion and perhaps also the condition of the original burn.