FILTRATION ACROSS THE VASCULAR WALL AS A FUNCTION OF SEVERAL PHYSICAL FACTORS

Abstract

A method for determining the filtration rate under controlled conditions is presented. This method depends on the continuous recording of the wt. of a perfused prep. The relationship between the osmotic pressure of the perfusion medium and the filtration rate is established for 4 colloidal systems: albumin, reconstituted plasma, pectin and gelatin. The relationship between the perfusion pressure and the filtration rate is established for 3 types of perfusion medium: colloid-free saline, albumin solns., and several dilutions of reconstituted plasma. The following conclusions may be drawn from the data presented: There is an inverse linear relationship between the osmotic pressure of the perfusion fluid and the filtration rate when albumin or plasma is used. There is a direct linear relationship between the perfusion pressure and the filtration rate. The blood vessels of the prep. used can retain to a high degree molecules of the magnitude of albumin. The blood vessels of the prep. used probably permit the passage of some fraction of the poly-dispersed gelatin system. The effective osmotic pressure of a colloid in the vascular system is equal to the osmotic pressure detd. in a physical osmometer only if the membrane used in the osmometer and the vascular wall both retain the same fraction of the colloidal system.