Biologists and Their Work 803 



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Karl von Baer (1792-1876). — Russian. Originated modern compara- 

 tive embryology. 



Robert Brown (1773-1858). — Scotch. A physician who opened the 

 field of plant physiology and genetics. Discovered the importance of 

 plant cell nucleus. 



Johannes Miiller (1801-1858). — German. He founded modern com- 

 parative anatomy, combined the knowledge of physics, chemistry, and 

 cytology (science of cells), and showed their proper relationships. 



Matthias Schleiden (1804-1881). — German. A botanist who together 

 with Schwann formulated the cell principle in 1839. 



Theodor Schwann (1810-1882). — German. A zoologist who with 

 Schleiden formulated the cell principle in 1839. 



Louis Agassiz (1807-1873). — American. A great investigator and 

 teacher in zoology. Studied the development of animals and paleon- 

 tology. He was professor of zoology and geology at Harvard University 

 and founded the Museum of Comparative Zoology there. 



Charles Darwin (1809-1882). — English. Formulated the theory of 

 natural selection (survival of fittest). Wrote Origin of Species in 1859. 



Asa Gray (1810-1888). — American. First great botanist of America. 

 Improved the system of plant classification. 



Gregor Mendel (1822-1884). — Austrian monk and scientist. Used 

 experimental method of studying heredity. Published Mendel's laws in 

 1865-1866. 



Louis Pasteur (1822-1895). — French. Bacteriologist and chemist. 

 "Father of modern bacteriology." Proved that microorganisms cause 

 fermentation and decay. Proved relationship between bacteria and cer- 

 tain diseases. 



Sir Francis Galton (1822-1911). — English. Formulated the laws of 

 filial regression and ancestral inheritance in heredity. 



Alfred Russel Wallace (1823-1913).— English. Shared with Darwin 

 the credit for the theory of natural selection. 



Thomas Henry Huxley (1825-1895). — English. Comparative anat- 

 omist and energetic defender of Darwin's theories. 



Julius Sachs (1832-1897). — German. Proposed experimental methods 

 for the study of photosynthesis, respiration, and transportation in plants. 



August Weismann (1834-1914). — German. Distinguished between 

 germ cells and somatic cells. Theory of continuity of germ plasm. 

 Identified chromatin material of nuclei as bearers of heredity. 



