The idea that fluid movement between the interstitial and the vascular space is canonically attributed to Ernest Starling. The same Starling as the Frank-Starling curve.
Much later on, an equation was created that represents this principle, now called the Starling equation.
The classical Starling principle has been mostly abandoned in favour of a modernised and far more complicated one. It is now understood that there is a supraendothelial glycocalyx that is very involved in regulating transvascular fluid movement. It is also apparent that most interstitial fluid is carried away by the lymphatic system rather than being reabsorbed by the venules.