In general, ectogenous infections of the vitreous respond unsatisfactorily to any type of therapy. The stimulation of the humoral and cellular body defenses by fever treatment and shock therapy and by local methods, such as withdrawal of small amounts of vitreous (Elschnig,1 Löwenstein and Samuels2 and Zur Nedden3) did not as a rule prevent the loss of function in the diseased globes. The topical and systemic chemotherapeutic procedures of former days barely improved the unfavorable prognosis. The present potent and less toxic antibacterial agents, such as the sulfonamide compounds and penicillin, introduced iontophoretically and supplemented by systemic treatment, did not check experimental endophthalmitis when the infection had spread from the anterior segment to the vitreous space.4 These results were not surprising in view of the slow metabolism of the vitreous and its anatomic position in relation to the main portals of entry of drugs into the