Introduction and objective: Starling assumed that the capillary works as Poiseuille’s tube, and its wall is impermeable to plasma proteins. Hence, fluid transfer across the capillary wall is dependent upon a balance between the capillary hydrostatic pressure and plasma protein oncotic pressure. This study aimed to verify if starling’s law is correct by testing if the capillary works as the Poiseuille’s tube or the new porous orifice (G) tube akin to a capillary ultrastructure anatomy.

Material and methods: A physiological study on the hind limb of sheep was conducted using both plasma proteins and crystalloid solutions. Each solution was run 3 times once through the artery then through the vein and back through the artery again while monitoring for oedema formation.

Results: Oedema only occurred when the fluid is run through the vein and not through the artery irrespective of the fluid used. This indicates that the capillary function as the G tube not Poiseuille’s tube and plasma proteins passes freely through the pores hence has no oncotic effect implying that Starling’s law is wrong on both forces.

Conclusion: The results affirmatively prove that the normal capillary works as G tubes not Poiseuille’s tubes. Also, plasma proteins move freely between the lumen of the capillary and the ISF space-nullifying its oncotic effect. The result also proves that starling’s law is wrong on both of its forces and the hydrodynamic of the capillary working as the G tube is the correct replacement for the capillary-ISF circulatory transfer.