page_title: Osmosis
section_title: History
hierarchical_section_title: Osmosis / History
caption_attribution_description: Deutsch: Darstellung des von Henri Dutrochet entwickelten Endosmosmeters aus Nouvelles recherches sur l'endosmose et l'exosmose, Paris, 1828.
context_page_description: Osmosis is the spontaneous net movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a selectively permeable membrane separating two solutions of different concentrations. Osmosis can be made to do work. Osmotic pressure is defined as the external pressure required to be applied so that there is no net movement of solvent across the membrane. Osmotic pressure is a colligative property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity.
  Osmosis is a vital process in biological systems, as biological membranes are semipermeable. In general, these membranes are impermeable to large and polar molecules, such as ions, proteins, and polysaccharides, while being permeable to non-polar or hydrophobic molecules like lipids as well as to small molecules like oxygen, carbon dioxide, nitrogen, and nitric oxide. Permeability depends on solubility, charge, or chemistry, as well as solute size.
context_section_description: Some kinds of osmotic flow have been observed since ancient times, e.g., on the construction of Egyptian pyramids. Jean-Antoine Nollet first documented observation of osmosis in 1748. The word "osmosis" descends from the words "endosmose" and "exosmose", which were coined by French physician René Joachim Henri Dutrochet (1776–1847) from the Greek words ἔνδον (éndon "within"), ἔξω (éxō "outer, external"), and ὠσμός (ōsmós "push, impulsion"). In 1867, Moritz Traube invented highly selective precipitation membranes, advancing the art and technique of measurement of osmotic flow.
caption: The "endosmometer" invented by Dutrochet.
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