The tendency in fluids to mix, or become equably diffused, when in contact. It was first observed between fluids of differing densities, and as taking place through a membrane or an intervening porous structure. An older term for the phenomenon was Osmose. Note: The more rapid flow from the thinner to the thicker fluid was then called endosmosis (formerly endosmose), and the opposite, slower current, exosmosis (formerly exosmose). Both are, however, results of the same force. Osmosis may be regarded as a form of molecular attraction, allied to that of adhesion. See also osmotic pressure.
... it reaches the intestine it begins to pass through its walls into the blood. In this absorption we find engaged another set of forces, the chief of which appears to be the physical force of osmosis. The force of osmosis has no special connection with life. If a membrane separates two liquids of different composition (Fig. i), a force is exerted on the liquids which cause them to pass through the membrane, each passing through the membrane into the other compartment. The force which drives these liquids ... — The Story of the Living Machine • H. W. Conn Read full book for free!