Roger Bacon used a convex lens as magnifying glass
Roger Bacon used a convex lens as magnifying glass
Period: Jan 1, 1200 to
Historical Development of the Cell Theory
Jan 1, 1485
Leonardo da Vinci used glass lenses to study small objects
Two spectacle-makers, Hans and Zacharias Janssen, constructed the first compound microscope using two lenses inside a tube
Robert Hooke further developed the compound microscope, including the use of the iris diaphragm. Hooke kept a detailed record of his observations. He first described cells in his description of a slice of cork under the microscope. He described it as 'all
Anton van Leeuwenhoek described unicellular organisms from his observations of a drop of stagnant rainwater as 'animalcules'. Leeuwenhoek also soaked some peppercorns in water for several days. When he examined a drop of this water under his microscope, h
Leeuwenhoek discovered bacteria from his observations of saliva
Rene Dutrochet stated that all animals and plants are made up of cells
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 formulated the cell theory that all living matter is composed of small units called cells
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 built the first electron microscope. Transmission electron microscopes and scanning electron microscopes were developed in the following decades. Details of internal cell structures were revealed