This website does readability filtering of other pages. All styles, scripts, forms and ads are stripped. If you want your website excluded or have other feedback, use this form.

Introduction of the Cell Theory

Annals of Clinical & Laboratory Science

Skip to main page content

  • © 2002 by the Association of Clinical Scientists, Inc.

Introduction of the Cell Theory

  1. Steven I. Hajdu
  1. Address correspondence to Steven I. Hajdu, M.D., 4 Forest Court, Oyster Bay Cove, New York 11791, USA; tel 516 922 5979; fax 516 562 4591.
Fig. 1.

Theodore Schwann, 1810–1882 (From Garrison’s History of Medicine, Saunders, Philadelphia, 1929, p455).

Technical improvements in microscopes in the late 1700s paved the way to accumulation of knowledge of cells in the early 1800s, and gradually the microscope ceased to be an instrument of amusement. It became an essential laboratory instrument. Laboratory workers, botanists, physiologists, and pathologists were able with the microscope to resolve points about a μm apart in a thin layer of squashed preparation, usually colored with a drop of iodine.

Theodore Schwann (1810–1882), a German physician and physiologist (Fig. 1), was assistant to Johannes Peter Müller (1801–1858), a prominent physiologist and pathologist in Berlin. Schwann discovered by microscopy that animal tissues, like plants, are composed of cells and that each cell has a nucleus. These are among the greatest scientific discoveries ever made.

Schwann published his observations in three articles in the January, February, and April 1838 issues of the Neue Not. Geb. Nat. Heilk. [1]. He described nucleated cells of notochordal tissue and cartilage in the larvae of toads, as well as in the kidney, liver, pancreas, salivary gland, and connective tissues of pig embryos. His articles were followed in 1839 by his landmark book: “Mikroskopische Untersuchungen über die Uebereinstimmung in der Struktur und dem Wachsthum der Thiere und Pflanzen” (Microscopic investigations on the similarity of structure and growth of animals and plants) [2].

Schwann was a devout Catholic and despite the fact that his 270 page-book was largely a reiteration of what he had already published a year earlier, he submitted the manuscript to the Archbishop of Malines for approval before publication. He wrote in his Untersuchungen that “The tissues of animals are formed from cells. The globules of lymph, pus, and mucus are cells with their walls distinct and isolated from each other. Horny (squamous) tissues are cells with distinct walls, but united into coherent tissues; bone and cartilage are formed of cells whose walls have coalesced; fibrous tissue and tendon are cells which have split into fibers; and muscle, nerves and capillary vessels are cells of which both the walls and cavities have coalesced.” He concluded that the “One common principle of development… for the most highly differentiated organisms (plants and animals)… is the formation of cells.” (Fig. 2).

In his publications, Schwann gave full credit to his friend, Mattias Jacob Schleiden (1804–1881), a dissatisfied lawyer turned botanist, for informing him about the presence of nucleated cells in plants, which gave him the idea of looking for the same phenomenon in animal tissues.

Botanists had long known that plants are composed of cells. In 1665, an English botanist Robert Hooke (1635–1703) coined the term “cell” to designate the microscopic units in cork [3]. The cell nucleus was discovered in 1831 by a Scotch botanist and physician, Robert Brown (1773–1858) [4]. Jakob Henle (1809–1885), another assistant of Johannes Müller in Berlin, reached the conclusion in 1837 that there is some similarity between cells of plants and animals [5]. But, the predecessors of Schwann did not generalize their findings as Schwann did. Schwann presented his comparisons of plant and animal tissues in a concise manner. His success was mainly due to his ability to describe and illustrate his microscopic observations accurately, drawing conclusions from the work of others, and formulating his opinion in a most convincing way.

There is no question that Schwann’s published works laid the foundations for the cell theory, but it must be recognized that, as often stated, discoveries are not made in isolation. Nonetheless, the important discoverer is the one who presents his contribution in such a way that the discovery becomes accepted in the scientific world. This was eminently accomplished by Schwann.

It is amazing that Schwann accomplished almost all of his major discoveries before he was 30 years old. These dicoveries include the action of pepsin [6], the role of germs in fermentation and putrefaction [7], the importance of bile in digestion [8], the essentiality of air for embryonic development [9], and the description of the nerve sheath that is named after him [10].

In 1839, shortly after his Untersuchungen was published, Schwann was appointed as a professor at the Catholic University of Louvain, Belgium. (At the same university 300 years earlier, Andreas Vesalius had studied and performed his first anatomic dissections.) In 1848, Schwann became professor of anatomy and physiology at the University of Liége, near the Belgian town of Bastogne, a short distance from the German border. He remained in Liége and lectured in French, his adopted language, until his death at age 72.

Within a few years after Schwann had concluded that the cell is the ultimate morphological unit of tissues and organs, two atlas texts of histopathology were published independently in 1843 by Julius Vogel (1814–1880) in Germany [11] and in 1845 by Hermann Lebert (1813–1878) in France [12]. With these printed volumes, the cell theory, introduced and publicized by Schwann in 1838–1839, became universally accepted as scientific fact.

View larger version:
    Fig. 2.

    Schwann’s illustrations of various kinds of animal cells. The figure shows bronchial cartilage of the tadpole (top left), mature cartilage from pig embryo (top center), fibers (top right), columnar cells (bottom left), collection of muscle and other connective tissue cells (bottom center), and nerve fiber (bottom right), (from Schwann’s “Untersuchungen” [2]).


    1. Schwann T. Ueber die Analogie in der Structur und dem Wachsthum der Thiere und Pflanzen.Neue Not Geb Nat Heil 1838;Jan:33–36; 1838;Feb:25–29; 1838;Apr:21–23. Google Scholar
    2. Schwann T. Mikroskopische Untersuchungen über die Uebereinstimmung in der Strucktur und dem Wachsthum der Thiere und Pflanzen. Sander, Berlin, 1839. Google Scholar
    3. Hooke R. Micrographia, or some physiological descriptions of minute bodies made by magnifying glasses; with observations and inquiries thereupon. J Martyn & J Allestry, London, 1665. Google Scholar
    4. Brown R. Observations on the organs and mode of fecundation in Orchideae and Asclepiadeae.Trans Linn Soc 1829–32;16:685–746. Google Scholar
    5. Henle F. Symbolae ad anatomiam villorum intestinalium, imprimis eorum epithleii et vasorum lacteorum. Hirschwald, Berolini, 1837. Google Scholar
    6. Schwann T. Ueber das Wesen des Verdauungsprocesses. Arch Anat Physiol Wiss Med 1836;90–138. Google Scholar
    7. Schwann T. Vorlaüfige Mittheilung betreffend Versuche über die Weingährung und Fäulniss. Ann Phys Chem 1837;41:184–93. Google Scholar
    8. Schwann T. Versuche um Auszumitteln, ob die Galle im Organismus eine für das Leben wesentliche Rolle spielt.Arch Anat Physiol Wiss Med 1844;127–159. Google Scholar
    9. Schwann T. De necessitate aëris atmosphaerici ad evolutionem pulli in ovo incubito. Nietackianis, Berolini, 1834. Google Scholar
    10. Müller J. Handbuch der Physiologie des Menschen. Hölscher, Coblenz, 1834. Google Scholar
    11. Vogel J. Icones Histologiae Pathologicae. Voss, Leipzig, 1843. Google Scholar
    12. Lebert H. Physiologie Pathologique ou Recherches Cliniques, Expérimentales et Microscopique. Bailliere, Paris, 1845. Google Scholar
    « Previous | Next Article » Table of Contents

    This Article

    1. Ann Clin Lab Sci Winter 2002 vol. 32 no. 1 98-100
    1. » Full Text
    2. Full Text (PDF)


    1. Series:
      • A Note from History


    1. Email this article to a colleague
    2. Alert me when this article is cited
    3. Alert me if a correction is posted
    4. Similar articles in this journal
    5. Similar articles in Web of Science
    6. Similar articles in PubMed
    7. Download to citation manager

    Citing Articles

    1. Load citing article information
    2. Citing articles via Web of Science
    3. Citing articles via Google Scholar

    Google Scholar

    1. Articles by Hajdu, S. I.
    2. Search for related content


    1. PubMed citation
    2. Articles by Hajdu, S. I.

    Related Content

    1. Load related web page information

    Navigate This Article

    1. Top
    2. References

    Current Issue

    1. May-June 2019, 49 (3)
    1. Alert me to new issues of ACLS

    The Association of Clinical Scientists
    publishes Annals of Clinical & Laboratory Science.

    Stanford University Libraries' HighWire Press ®
    assists in the publication of ACLS Online.

    Copyright © 2019 by the Association of Clinical Scientists

    • Print ISSN: 0091-7370
    • Online ISSN: 1550-8080