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Aristotle had made many disections and expirements, and introduced the idea existing cells come from other cells.
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Consisted of three draw tubes inserted into the ends of the flanking tubes. The eyepiece lens was bi-convex and the objective lens was plano-convex, a very advanced compound design for this time period. http://www.history-of-the-microscope.org/hans-and-zacharias-jansen-microscope-history.php
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Antoni van Leeuwenhoek grinds up and polishes small lenses of great curvature.
http://inventors.about.com/library/inventors/blleeuwenhoek.htm -
Robert Hooke uses earlty microscope to observe a cork.
http://www.britannica.com/EBchecked/topic/101517/cell-theory -
In what is perhaps his best-known experiment, van Helmont placed a 5-pound (about 2.2-kg) willow in an earthen pot containing 200 pounds (about 90 kg) of dried soil, and over a five-year period he added nothing to the pot but rainwater or distilled water. After five years, he found that the tree weighed 169 pounds (about 77 kg), while the soil had lost only 2 ounces (57 grams). He concluded that “164 pounds of wood, barks,
http://www.britannica.com/EBchecked/topic/260549/Jan-Baptista-van-Helmont -
Lorenz Oken elaborated Wolfgang von Goethe’s theory that the vertebrate skull formed gradually from the fusion of vertebrae. Although the theory was later disproved, it helped prepare a receptive atmosphere for Charles Darwin’s theory of evolution.
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Schleiden was the first to recognize that all plants, and all the different parts of plants, are composed of cells.
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Schleiden mentioned his idea. Schwann, who came to similar conclusions while studying animal tissues, quickly saw the implications of their work. In 1839, he published "Microscopic Investigations on the Accordance in the Structure and Growth of Plants and Animals," which included the first statement of the cell theory: All living things are made up of cells.
http://www.britannica.com/EBchecked/topic/101517/cell-theory -
Rudolf Virchow (1821-1902) extended the work of Schleiden and Schwann by proposing that all living cells must rise from pre-existing cells. This was a radical idea at the time because most people, scientists included, believed that nonliving matter could spontaneously generate living tissue. The inexplicable appearance of maggots on a piece of meat was often given as evidence to support the concept of spontaneous generation. http://www.britannica.com/EBchecked/topic/101517/cell-theory
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In 1822 scientist Louis Pasteur set out to disprove spontaneous generation with a now-classic experiment that both firmly established the cell theory beyond doubt and solidified the basic steps of the modern scientific method.
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a German botanist Matthias J Schleiden interested in plant anatomy, stated, “the lower plants all consist of one cell, while the higher ones are composed of many individual cells.
http://www.britannica.com/EBchecked/topic/101517/cell-theory -
recognized and named the nucleus as a constant constituent of living cells in most plants, and improved the natural classification of plants by establishing and defining new families and genera. He also contributed substantially to knowledge of plant morphology, embryology, and geography.
http://www.britannica.com/EBchecked/topic/81618/Robert-Brown
