Up to the present time no work has been published on the determination of the relative value of the newer surface anesthetics used by the ophthalmologists in this country. Marx,1Hoffmann2and Schornstein3have compared the drugs commonly used on the continent. Clinical reports on the individual preparations have recently been made as follows : on butyn, by the Committee on Local Anesthetics, of the Section on Ophthalmology of the American Medical Association,4onp-nbutylaminobenzoyl-dimethylamino-ethanol hydrochloride by Wilmer and Paton5and Rauh6and on nupercaine, by Dillon and Greer7and Bochner.8This work was undertaken to compare the effect of 2 per cent cocaine, 2 per cent metycaine, 1 per cent butyn, 1 per cent phenacaine, 0.5 per centp-nbutylaminobenzoyl-dimethylamino-ethanol hydrochloride and 1: 500 nupercaine. Cocaine, the oldest and the best known of these drugs, has