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367
Aristotle 367 B.C.
Disected animals and studied the ways they reproduce. -
400
Spontaneous Generation 400 B.C.
The idea that nonliving matter can generate living tissue. -
Period: 400 to
Spontaneous Generation to Cell Theory
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Zacharias Jansen
Developed a microscope with 2 tubes with a lens at the end of each focused by twisting the tubes. His invention allowed other scientists to observe different things. -
Jan Baptist van Helmont
His fermentation experiment allowed him to believe that each of the principle organs of the body contain a ferment that allowed the assimilation of food into body tissues. He also thought disease was caused by foreign ferments, thus diseases had to be treated indicidually with its own cure. -
Robert Hooke
He observed cork cells, he developed his discovery into the cell theory. He examined his experiments using a primitive microscope. -
Anton van Leeuwenhoek
In 1678 Leeuwenhoek reported that he observed "little animals" in a microscope. -
Robert Brown
Known for describing microscopic particle agitation in water or gases, movement now called Brownian motion. Gave the name nucleus to the specialized body that regulates the functions of a living cell. -
Matthias Jakob Schleiden
He was the first to recognize that all plants and plant parts are composed of cells. -
Theodor Schwann
Made similar conclusions, like Schleiden while examining animal cells. He also published "Microscopic Investigation on the Accordance in the Structure and Growth of Plants and Animals." His book had the first statement of the cell theory "all living things are made of cells." -
Lorenz Oken
Observed that plants and animals are made up of tiny living "infusoria" that led to the cell theory. -
Albrecht von Roelliker
His experiments led to the discoveries of the stucture of the smooth muscle, the development of red blood cells, and the significance of the germ layers in development. -
Rudolf Virchow
Said that cells must come from pre-existing cells, this idea was radical because at the time people believed in spontaneous generation. Also analyzed the effects of diseases in organs and tissues. He studied diseases such as cancer. -
Louis Pasteur
He set out to disprove spontaneous generation by using a now-classic experiment. Also had the idea that bacteria spread and living things came from living things. -
Cell Theory
Living things are composed of cells and come from cells.
