How was the membrane structure known and by whom?

The were known by chemical and biochemical analysis, it were ambiguous for a long time until 1925 where Gorter and Grindle who were studying RBC structure, They suggested that polar heads of lipids are directed inwardly to the cytosol and outwardly towards the ECM whereas the non polar tails are directed towards each other, (bilayer shape maintained by hydrophobic interactions), however no clear explanation about proteins present, until 1935 (Danielli and Davson) where proteins are absorbed by two polar sides or integrated through the membrane forming a channel, which was confirmed by studies (freeze-fracturing technique) and (staining by osmium tetroxide remarking trilaminar appearance of membrane- two outer dark layers called osmophillic and one inner bright layer.)