The mechanism for this "no reabsorption rule" is called the glycocalyx model, or the Michel-Weinbaum model in honour of two scientists who independently described the glycocalyx model. Briefly, the interstitial fluid colloid osmotic pressure πi has been found to have no effect on Jv and the colloid osmotic pressure difference that opposes filtration is now known to be π'p minus the subglycocalyx π, which is close to zero while there is adequate filtration to flush interstitial proteins out of the inter endothelial cleft. Consequently, Jv is much less than previously calculated, and the unopposed diffusion of interstitial proteins to the subglycocalix space if and when filtration falls wipes out the colloid osmotic pressure difference necessary for reabsorption of fluid to the capillary.