Schleiden and Schwann: the cell as the common unit of structure and growth in plants and animals

1838–1839 Life and health theory

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The position that the cell is the common unit of structure and growth of plants and animals, and that the tissues of both kingdoms are developments of cells according to the same laws.

The position took shape in two papers. In 1838 the German Matthias Schleiden put Brown's nucleus at the centre of the story of how a plant cell comes to be: first the nucleus appears, then the cell forms around it. The German Theodor Schwann, having heard this from Schleiden, found the same in animals, from the notochord of frog larvae to cartilage, bone and nerve, and in 1839 declared the generalisation. In the third, philosophical part of his book Schwann explained the life of the cell not by a vital force but by the forces of matter itself, and cited alcoholic fermentation as a model of what happens in every cell.

The mechanism of cell origin, free formation within a structureless 'blastema', Schwann took from Schleiden and got wrong: Remak and Virchow would correct it. But the proposition that the cell is the unit of all living things stood, and in Florkin's view it marks the beginning of the mechanistic school in physiology.

Why this date

The axis year is 1839, when Schwann's book 'Mikroskopische Untersuchungen über die Übereinstimmung in der Struktur und dem Wachstum der Thiere und Pflanzen' (Berlin, 1839) extended the theory to animals. The lower bound of the label is Schleiden's paper 'Beiträge zur Phytogenesis' in Müller's Archiv for 1838, pp. 137-176, on the plant cell; Schwann's preliminary notes appeared in Neue Notizen in 1838 (Florkin's bibliography in the DSB). The date follows the book of 1839, and the QID is that of the book.

What it grew from

• Brown: the nucleus as a regular constituent of the living cell

  influenced · Confidence: high

  Schleiden himself held that the crucial prerequisite of his cell theory was Brown's calling attention to nuclei; after meeting Brown in 1836 he built the first cell theory that gave the nucleus an essential role, and passed it on to Schwann.

  Dispute: Mylott reports Schleiden's own words about the 'crucial prerequisite', which taken literally would justify "prerequisite for". The kind is kept as "influenced" by the rule of parsimony: without Brown's nucleus a theory of the cell as the unit of life would still have been possible; what would have been impossible is Schleiden's particular scheme of cell formation around a nucleus, which fifteen years later proved wrong.

  Link sources

  • Anne Mylott, «Schleiden, Matthias Jacob», New Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    In contrast Schleiden considered the crucial prerequisite to his cell theory to have been Robert Brown's calling attention to nuclei.

  • Anne Mylott, «Schleiden, Matthias Jacob», New Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    After meeting with Brown in 1836, Schleiden noticed that nuclei were the first structures to develop in the embryo and that cells formed around them. He propounded the first cell theory that gave an essential role to the nucleus.

  • William T. Stearn, «Brown, Robert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    Embedded in this paper is a discovery highly relevant to the cell theory, and thus to the development of cytology.

  • Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    It was not until 1830 that the perfecting of the microscope permitted Robert Brown to recognize the presence of the nucleus as the essential characteristic of the plant cell.

  "Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

• Brewer's yeast turns out to be a living organism: Cagniard-Latour, Schwann, Kützing

  influenced · Confidence: medium

  Schwann was one of the three who showed that yeast is alive, and Florkin derives the cell theory from the same commitment that guided his fermentation work: to replace the 'vital force' with an exact explanation. In the third part of the 1839 book alcoholic fermentation is cited as the model of the metabolism repeated in every cell.

  Dispute: The confidence is deliberately medium. Florkin and Bechtel with Bollhagen connect the yeast work and the cell theory through Schwann's personal programme (a mechanistic explanation of the life of the cell), not through a documented derivation of one from the other. Barnett (2003), who treats the discovery of 1837 in detail, describes both of Schwann's works but asserts no link between them. The link runs only through Schwann's contribution; Cagniard-Latour and Kützing have no bearing on the cell theory.

  Link sources

  • Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    had already been clearly manifested in his studies of muscle, of the mechanism of digestion, and of fermentation. His tendency to introduce a more exact mode of explanation than the current one in terms of the “vital force” culminated in the formulation of the cell theory.

  • Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    In addition, all the parts of the cell itself may be chemically modified during the process of its growth by a “metabolic power” that is an attribute of the cell itself; this is demonstrated by alcoholic fermentation, which provides a representation of the process that is repeated in all the cells of an organism.

  • Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    In January 1836 he noted in his laboratory notebook the conclusion that alcoholic fermentation is the work of a live organism.

  • William Bechtel, Andrew Bollhagen, Philosophy of Cell Biology, Stanford Encyclopedia of Philosophy (2019) Verified 20 Sep 2026

    When a year later he argued that fermentation could not occur without the involvement of a whole living yeast cell (Schwann 1837), some critics took Schwann to be claiming that living systems exhibited mysterious vital properties. But for Schwann this was consistent with his mechanist approach—the metabolic processes only occurred when the responsible catalysts were brought together in cells.

  "Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

What grew out of it

• Remak: animal cells arise by division that begins with the nucleus

  improved · Confidence: high

  Remak accepted Schwann's cell as the unit of the animal body but replaced the erroneous mechanism of its origin: not free formation in a cytoblastema but division of an existing cell, beginning with the nucleus. Hintzsche and Lagunoff both present this as a direct correction of Schwann.

  Dispute: The kind is "improved", not "refuted by": only part of Schwann's theory (the mode of cell formation) was refuted, while its central entity, the cell as the unit of life, was retained and strengthened. cell_theory_1839 is therefore not marked as a dead end.

  Link sources

  • Erich Hintzsche, «Remak, Robert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    Of particular importance was Remak's suggestion that, contrary to Schwann's view, the intercellular substances of the cartilage and connective tissue cannot be a cytoblastema.

  • David Lagunoff, A Polish, Jewish Scientist in 19th-Century Prussia, Science 298 (5602), 2331 (2002)

    Contradicting Schwann, Remak placed animal cell division at the forefront of cell theory.

  • David Lagunoff, A Polish, Jewish Scientist in 19th-Century Prussia, Science 298 (5602), 2331 (2002)

    Schwann was convinced that a similar sequence occurred in animal tissues, but placed the formation of most animal cells in the extracellular milieu (the "cytoblastem").

  "Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

• Virchow: every cell from a cell, and disease as the life of cells under altered conditions

  improved · Confidence: high

  Florkin, following Ackerknecht, describes the theory of Remak and Virchow as the fourth cell theory, whose first part repeats Schwann (the organism consists of cells, the cell bears all the properties of life) and whose second part, omnis cellula e cellula, cancels his error about the blastema. Virchow carried this corrected theory into pathology.

  Link sources

  • Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    Ackerknecht’s fourth cell theory, which remians current, is that of Remak and Virchow, the first part of which follows Schwann in acknowledging the cellular composition of organisms, with the cell as the vital element, the bearer of all the characteristics of life. The second part of this theory, expressed in the dictum “omnis cellula e cellula,” contradicts Schwann’s erroneous belief in the formation of cells within a “blastema.”

  • William Bechtel, Andrew Bollhagen, Philosophy of Cell Biology, Stanford Encyclopedia of Philosophy (2019) Verified 20 Sep 2026

    In any case, Schleiden's and Schwann's accounts of cell formation were soon set aside as more researchers reported on cell division and Schwann's concerns with mechanism were supplanted by other concerns. Virchow (1855), a pathologist, offered a theoretic argument that only a process like cell division could explain the transmission of disease and coined the oft-cited dictum "omnis cellula e cellula" (all cells come from cells).

  • David Lagunoff, A Polish, Jewish Scientist in 19th-Century Prussia, Science 298 (5602), 2331 (2002)

    Virchow, widely recognized then and now as the foremost proponent of cell division, commenced his conversion from Schwann's doctrine in 1850 but apparently remained ambivalent as late as 1854, particularly in regard to tumor growth.

  "Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

Node sources

• Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

  In 1839, in his Mikroskopische Untersuchungen, Schwann formulated what Ackerknecht called the third cell theory, which insists on the common cellular origin of every living thing.

• Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

  The error suggested to Schwann by Schleiden—the formation of cells within a blastema, which Schwann tentatively compared to the phenomenon of crystallization—satisfied his chemical and physical preferences to such a high degree that one can understand a little more easily why he accepted it on the strength of arguments as weak as those he presented to demonstrate it

• Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

  Schwann’s cell theory can be regarded as marking the origin in biology of the school of mechanistic materialism that Brücke, du Bois-Rey-mond,Helmholtz, and Carl Ludwig made famous

• Anne Mylott, «Schleiden, Matthias Jacob», New Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

  After meeting with Brown in 1836, Schleiden noticed that nuclei were the first structures to develop in the embryo and that cells formed around them. He propounded the first cell theory that gave an essential role to the nucleus.

• Anne Mylott, «Schleiden, Matthias Jacob», New Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

  After Schleiden told Theodor Schwann about nuclei forming cells, Schwann recognized a similar process as fundamental to animal development, and compared cell formation to crystallization (1839).

• Anne Mylott, «Schleiden, Matthias Jacob», New Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

  “Beiträge zur Phytogenesis.” Müller's Archiv für Anatomie, Physiologie, und wissenschaftliche Medicin, 1838: 137–176.

"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

Further reading

Not evidence: these carry no quotation and support nothing we wrote. They are books and scans to read next.

• Wikidata Q51390546: Mikroskopische Untersuchungen über die Uebereinstimmung in der Struktur und dem Wachsthum der Thiere und Pflanzen, Theodor Schwann, 1839 (1839)

Open this node on the map · Wikidata: Q51390546