EXPERIMENTAL DATA ON THE PROBLEM OF THE PERMEABILITY OF THE CORNEA: II.-The Permeability of the Excised Cornea with Respect to Water and Chloride Ions.

1'HE data in the literature dealing with the permeability of the cornea give variable and dissimilar results both with regard to the irreciprocity of the.permeability and to the magnitude and quality of the necessary osmotic forces and to the rate of diffusion. The purpose of our experiments was to estimate these discrepancies using a different method, and to examine the points brought out above. Method:-Our experimental apparatus was similar to the chamber system described by Hamburger. The chambers were separated by the excised cornea. Various solutions were placed in the two chambers and the changes in volume, and in the chloride ion concentration were determined. The volume change was determined by capillary measurement, the chloride ion by a micro. method. (Diameter of capillary 08mm. 10 units of the capillary scale equalled 5c.mm.) The volume of each chamber was approximately 4c.cm. The solutions used were pig's blood diluted with Ringer's solution to various degrees. The air bubbles in each section were carefully displaced and liberated. The corneae were obtained with the aid of a slice made through the equator of the