Figure 2.

Timeline 1665–1925. Summary of the main contributions related to cell membrane discovery between the coining of the term “cell” in biology and the first studies on cell membrane structures. The events are approximatively ordered from top to bottom from the earlier events to the most recent. Although the studies are sometimes difficult to classify, the colors of the boxes reflect some major research axes influent to this history: dark blue, doubts about the existence of cell membranes; orange, osmotic studies; red, studies with artificial membranes; purple, electrophysiology works; dark green, direct description of membranes. Although most of these contributions were highly interconnected, full lines between boxes highlight particularly important relationships and dashed lines point out to contradictory views in major controversies.