DEMONSTRATION OF A CAPILLARY PERMEABILITY FACTOR IN TISSUE EXTRACTS FROM NORMAL RABBITS

Abstract

Recently it has been shown that trypan blue after intravenous injection localizes and concentrates in areas of inflammation produced by the local application of xylene in the rabbit's skin only when the dye is given immediately or within approximately three hours after application of the irritant. Three hours after application of the xylene the skin shows all the cardinal features of inflammation. A second application of xylene to this area of inflammation immediately before the intravenous injection of trypan blue apparently produces some change in the tissues and capillaries that permits the localization and concentration of the dye in the area.¹ The studies of Rous and Smith² have shown that colloidal dyes escape from the capillaries in the skin and the adjacent part of the venules. A definite gradient of permeability occurs in the small blood vessels. After local application of an irritant the dye escapes from a