I. Intraocular Clearance of Antibiotic in Inflamed Eyes. We propose to investigate the effect of infection on the intravitreal clearance of antibiotic in primates. We will produce S. aureus endophthalmitis in Rhesus monkeys and measure antibiotic levels in ocular tissues and humors at various times after intravitreal injection of 100 micrograms gentamicin or 1000 micrograms carbenicillin. We will aso investigate the mechanism of accelerated ocular clearance of aminoglycosides from infected rabbit eyes in different states of inflammation: 1) noninflamed (normal), 2) sterile inflammation (proteose-peptone), 3) S. aureus endophthalmitis and 4) Pseudomonas endophthalmitis. II. Probenecid: Because probenecid prolongs the ocular halflife of intravitreal penicillins, we plan to assess the feasibility of concomitant intraocular injection of probenecid. The toxicity of various doses of intravitreal probenecid in rabbit eyes will be determined by direct opthalmoscopic observation, ERG's, and histologic examination.