“Medical physiologists are also likely to think of the cell’s interior as a watery solution which “fills the space enclosed by the cell membrane.” It is this image of the organism that has made traditional biochemistry possible, since enzymes extracted from cells and dissolved in water had been thought to function the way they function in the living state. However the living cell isn’t like a tiny water-filled test-tube... but the idea that the cell itself is a sort of watery solution, in which the water-soluble enzymes float, randomly mingling with dissolved salts, sugars, etc., persists, and makes the idea of a semipermeable membrane seem necessary.” -Ray Peat