V. The Modern Period, 1789–1914 > B. The French Revolution and Europe, 1789–1914 > 7. Western and Central Europe, 1848–1914 > a. Social, Cultural, and Economic Trends > 4. Science and Learning > b. Chemistry, Biology, and Geology
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  The Encyclopedia of World History.  2001.
 
 
b. Chemistry, Biology, and Geology
1848
 
Louis Pasteur (1822–95), in a series of brilliantly conceived and executed experiments, demonstrated the connection between the optical activity of organic molecules and crystalline structure, thus founding stereochemistry.  1
 
1848
 
Claude Bernard (1813–78) demonstrated the ability of the liver to store sugar in the form of glycogen. His widely read Introduction à l'étude de la médecine expérimentale (1865) influenced the literary world as well as scientists.  2
 
1852
 
Edward Frankland (1825–99) announced his theory of valency, that is, each atom has a certain “valency,” or capacity for combining with a definite number of other atoms.  3
 
1856–64
 
Bernard evolved the concept of the milieu intérieur, envisioning that cells were autonomous physiological units, yet were dependent upon and protected by the internal environment of the whole organism.  4
 
1856–66
 
Hermann Helmholtz (1821–94) extended the doctrine of specific nerve energies developed by Johannes Müller to vision and hearing, indicating the penetration of physics and physiology into psychology.  5
 
1857–60
 
Louis Pasteur demonstrated that fermentation was a product of yeast cell activity. This challenged the view of Liebig that the ferment was merely an unstable chemical substance.  6
 
1858
 
Rudolph Virchow (1821–1902) in Die Cellularpathologie declared that disease reflects an impairment of cellular organization. Here, too, he stated his famous generalization “omnis cellula e cellula” (all cells arise from cells) and described the cell as the basic element of the life process.  7
 
1858
 
Friedrich A. Kekulé (1829–96) published Über die Konstitution und die Metamorphosen der chemischen Verbindungen und über die chemische Natur des Kohlenstoffs, in which he recognized that carbon is quadrivalent, and that carbon atoms link together to form long chains that serve as skeletons for organic molecules.  8
 
1858
 
Stanislao Cannizzaro (1826–1910) showed that one could unambiguously determine atomic weights. He was thus able to provide a table giving the correct molecular formulas of many compounds.  9
 
1859
 
Gustav R. Kirchhoff (1824–87) and Robert W. Bunsen (1811–99) began researches that made spectrum analysis a powerful method for the investigation of matter. They showed that a chemical element was clearly characterized by its spectrum, and by spectrum analysis they were able to discover previously unknown elements.  10
 
1859
 
Darwin amassed 25 years of careful research in Origin of Species. Inspired by the evidence in geology, paleontology, zoogeography, and domestic animal breeding, he declared that species evolved through variation and the natural selection of those individuals best suited to survive in given environmental conditions. A similar theory was developed independently by Alfred R. Wallace (1823–1913).  11
 
 
 
The Encyclopedia of World History, Sixth edition. Peter N. Stearns, general editor. Copyright © 2001 by Houghton Mifflin Company. Maps by Mary Reilly, copyright © 2001 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

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