In a previous paper,1 we showed how the Leber bubble manometer may be used to estimate the rate of circulation of the aqueous. The present study represents the further application of the same technic to the measurement of the rate of escape of fluid from the anterior chamber under various conditions The present state of our knowledge in regard to the mechanism by which the aqueous is reabsorbed into the circulating blood leaves much to be desired. The older notion that the fluid leaks out through actual pores in the walls of Schlemm's canal has been disproved by injections of colloids and suspensoids into the anterior chamber. Duke-Elder2 showed that the hydrostatic pressure in the vessels connected with Schlemm's canal is normally above the intra-ocular pressure, so that the conception of simple filtration has had to be abandoned. No evidence has ever been discovered, in spite of