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Jan 1, 1260
Roger Bacon invents the glass lens.
Based, in part, on the studies of Arab opticians, Roger Bacon studies the properties of glass lenses. His describes his work in his major treatis, Opus Majus, which he completes in 1267. Bacon is credited with the invention of the glass lens. -
Jan 1, 1286
Eyeglasses were invented.
There is a debate among historians as to the when eyegalsses were invented. Some claim that they werre invented in Italy in about 1286. However others claim that they were i9nvented earlier in India. -
Zaccharias and Hans Jansen make the first microscope.
Zaccharias Janssen is associated with the early development of the telescope and the simple and compound light microscopes. Confusion suurounds the role of Zaccharias in the microscope's invention. It is generally reported, and seems highly likely, that Hans Janssen, Zaccharias' father, either helped his son build the first microscope or built the first microscope himself in 1595. -
Galileo constructs a working compound microscope.
While Zaccharias and Hans Jansen are widely credited with inventing the compound microscope, Many credit Galileo with the invention. His microscope was built at about the same time he was building his telescope. Soon after his work on the telescope, Galileo used the telescope at close range to magnify small objects. Like the Galilean teloscope, the Galilean compound microscope had one concave and one convex lens mounted in a rigid tube. -
Galileo publishes illustrations of magnified insects .
Illustrations of microscopic views of insects made using one of Galileo's microscopes were published in 1625 and appear to have been the first clear documentation of the use of a compound microscope. -
Robert Hooke publishes his microscopic observations of cork.
In 1665, Robert Hooke published his major work Micrographia with the Royal Society London. In it, he reports his observation of the microscopic appearance of cork and coins the term "cell" in reference to the microscopic compartments he observed. -
Leeuwenhoek observes living cells.
Anton van Leeuwenhoek produced some of the very best magnifying lenses of his day and used them to construct simply microscopes capable of nearly 300 X magnification. Using these simple microscopes, he was the first to view living cells. -
Henri Dutrochet proposes "The cell is the fundamental element of organization."
Dutrochet was an accomplished French biologist credited with, among other things, early research into the development of embryos and determining the basis for osmosis. Following up on the work of Ludolph Treviranus and Johann Moldenhawer, who put forth the notion that cells were separable into individual units, Dutrochet proposed the idea that "The cell is the fundamental element of organization". -
Scheliden reports that plants are made of cells.
In his monograph Beiträge zur Phytogenesis (Contributions of Phytogenesis), which was published in 1838, he described his observations that different parts of the plant are made of cells, and he concluded that all plant tissues are made of cells and that the embryonic plant grows from a single cell. -
Theodor Schwann concludes that "All living things are composed of cells and cell products".
Schwann collaborated with Schleiden on studies of the microscopic structure of plants and animals. In 1839, a year after Scleiden reported his studies on plants, Schwann published his manuscript entitled Microscopic Investigations on the Accordance in the Structure and Growth of Plants and Animals, in which he formally concludes that "All living things are composed of cells and cell products". -
Robert Remak shows that cells come from pre-existing cells.
Remak's experimental observations also showed, for the very first time, that cells come from pre-existing cells through a cell divsion process. -
Rudolf Virchow popularizes the maxim "Every cell originates from another existing cell like it.").
Virchow popularized the maxim Omnis cellula e cellula ("Every cell originates from another existing cell like it."). It has been authoritatively claimed that Virchow plagarized Remak's work. Moreover, the maxim Omnis cellula e cellula has its origins with two other scientists, Francesco Redi and François-Vincent Raspail.