The turn of the century which marked the beginning of Dr. Verhoeff's career as an ophthalmologist was notable also for the publication of Leber's1 great monograph on the nutrition of the eye. This book was the climax of Leber's contributions to the understanding of the intraocular fluid exchange and, in a sense, marked the end of the classic period of research on glaucoma. It is refreshing even now to reread this lucid and far seeing exposition and to recapture something of the excitement which these studies must have had for the young student of those days. The culmination of Leber's work marked the completion of a cycle of anatomic and physiologic studies begun a generation earlier, but it was also the beginning of a new period in which biochemical methods and arguments were to struggle slowly to the fore. PHYSICOCHEMICAL FACTORS IN THE FORMATION OF THE AQUEOUS It is