A subject of such importance as intra-ocular tension requires careful analysis of the means used in its study. With this in mind one may well ask several questions about anterior chamber punctures. First, what are anterior chamber punctures? Most, if not all, authors mean by this a puncture of the cornea, usually near the limbus, with a small bore needleand a withdrawalof the aqueous more or less completely. Some leave the needle in place and attach a manometer ; some counterpuncture and leave the needle transfixing the cornea while they make their observations with or without another puncture, and some allow the aqueous to escape by paracentesis with a knife or keratome, then make their observations on the eyeball and even enucleate it if they so desire. The needle used is of small bore and the canal in the cornea is preferably oblique through the lamellae of