Cell Theory

  • Robert Hooke

    Robert Hooke
    further developed the compound microscope, including the use of the iris diaphragm. Hooke kept a detailed record of his observations.
  • Anton van Leeuwenhoek

    Anton van Leeuwenhoek
    Described unicellular organisms from his observations of a drop of stagnant rainwater as 'animalcules'.
  • Leeuwenhoek

    Leeuwenhoek
    Discovered bacteria from his observations of salvia
  • Robert Brown

    Robert Brown
    Noted that the cells of orchids he was observing under the microscope contained a structure inside the cell. He called this the 'nucleus'.
  • Matthias Schleiden and Theodor Schwann

    Matthias Schleiden and Theodor Schwann
    Formulated the cell theory that all living matter is composed of small units called cells
  • Rudolf Virchow

    Rudolf Virchow
    Stated that 'where a cell exists there must have been a pre-existing cell, just as the animal arises only from an animal and the plant only from a plant.
  • Ernst Ruska

    Ernst Ruska
    Built the first electron microscope. Transmission electron microscope. Transmission electron microscopes and scanning electtron microscopes were developed in the following decades. Details of internal cell structures were revealed.