Henri Dutrochet

Who Watched Water Cross A Living Skin · Physiologist & Botanist · 1776–1847

The country physiologist who named osmosis, built the instrument that measured it, and argued all his life that nothing a living body does requires a special force.

Who was Dutrochet?

Henri Dutrochet was born in 1776 at Néons-sur-Creuse in Poitou, into a family ruined by the Revolution. He qualified in medicine in Paris, served briefly as an army physician in Spain, and then withdrew to the family property in Touraine, where he did nearly all his scientific work alone and at his own expense. In 1824, in the Recherches anatomiques et physiologiques sur la structure intime des animaux et des végétaux, he stated that the cell is the fundamental element of the organisation of living things — a claim later credited to Schleiden and Schwann, to which he never pressed a rival title. Two years later he announced the phenomenon he called endosmosis and its opposite, exosmosis: place a concentrated solution behind a piece of animal membrane and stand it in water, and water crosses into the solution, swelling the vessel and driving a column of mercury up a tube. He built the instrument that measured that pressure, and he established the key fact — that certain membranes let water pass and hold the dissolved matter back, so water moves from the weaker solution into the stronger, and will do so against gravity. He proposed that this single physical process might account for the rise of sap and for how plants and animals absorb what they need. His attempt to explain the flow itself as an electrical effect did not survive, and the real mechanism was not settled for decades. He also showed that the stomata of a leaf open into internal air spaces, and that only the green parts of a plant take in carbonic acid and use light to build with it. He died in Paris in 1847.

Major achievements

• Named and described osmosis — endosmosis and exosmosis — in 1826
• Built the osmometer that first measured the pressure osmosis can raise
• Showed that some membranes pass water while holding back dissolved matter
• Stated in 1824 that the cell is the fundamental element of living organisation
• Demonstrated that stomata open into the air spaces inside a leaf

Life in brief

• 1776 — Born in Poitou: At Néons-sur-Creuse, into a family the Revolution would ruin.
• 1806 — Qualifies in medicine: In Paris, after an interrupted and unconventional education.
• 1808 — Army physician in Spain: Falls seriously ill and gives up practice soon afterwards.
• 1824 — The cell stated: Recherches anatomiques et physiologiques names the cell the fundamental element of organisation.
• 1826 — Endosmosis named: Announces the two-way flow across a membrane and coins the terms.
• 1828 — The instrument: Nouvelles recherches sur l'endosmose reports the pressure the flow can raise.
• 1837 — Plants and animals together: The Mémoires collect his work on sap, stomata and the greening of leaves.
• 1847 — Dies in Paris: With osmosis established and its mechanism still unexplained.

Explore the life of Dutrochet — five chapters

1. A Family Ruined, a Doctor Made — Poitou, Paris, and an army posting that ended a career
2. Stated First, Credited to Others — 1824, fifteen years before Schwann
3. Endosmosis — Water crossing a living skin, and the instrument that measured it
4. The Explanation That Would Not Stand — Electricity, and a hundred years of unfinished business
5. Stomata, Green Parts and Light — The plant work, and a quiet end

Read the five-chapter life of Henri Dutrochet →

Where Dutrochet appears in your course

Henri Dutrochet has a genuine claim on 1 lesson of the Pearson Edexcel International GCSE science course built into Incandio:

• Diffusion, Osmosis and Active Transport — Biology: In 1826 Dutrochet gave osmosis its name, and by 1828 he had built an instrument that measured how hard water pushes when it crosses into a strong solution — enough to drive a column of mercury up a tube. He also insisted, against most of the physiology of his day, that nothing living is needed to make it happen. He is the reason this page has a middle section, and he is the person you will argue with at the end of it.

Begin

• Start a conversation with Dutrochet — a dramatised, historically grounded AI portrayal
• Read the Historical Brief
• Explore the life of Dutrochet — five chapters
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