THE SEQUOIA 
result of successive catastrophes), rather than Unzformitarian- 
ism (the belief that the present condition of the earth has been 
brought about by a gradual, uniform change). The work of 
Cuvier in comparative anatomy is also important, and he is 
called the founder of this science. He recognized the principle 
of correlated growth, and in “Le Régne Animal” improved the 
classification of animals. 
The last century of our tree’s life was remarkable for the dis- 
coveries in all branches of natural science. De Blainville (1839- 
1849) and Lyell (1797-1875) made valuable contributions to 
paleontology and geology. Lyell’s “Principles of Geology” 
(1830-1833) dealt a death blow to catastrophism, and is a work 
second only in importance to the “ Origin of Species.” 
Milne-Edwards (1800-1818) enunciated the principle of. the 
physiological division of labor. 
Von Baer (1828) announced the law that bears his name, 
namely, “individual development is a recapitulation of race 
development.” 
Schleiden and Schwann (1838-1839) discovered cells in plants 
and animals, and propounded the cell theory. 
Valentin (1839) named the “nucleus,’’ and was the first to 
speak of the “cell theory.”’ 
Purkinje and von Mohl (1840) named the substance of the cell 
protoplasm. 
Serres (1842) asserted that all missing links would be found 
in embryology. 
De Barry (1843) observed the union of sperm and ovum. 
KOolliker (1846) demonstrated that sperm are developed from 
the tissues of the testes. 
Owen (1846) pointed out the difference between homologous 
organs, for example, the arm of man, fore limb of horse, and wing 
of bird, organs which are formed on the same structural plan, 
and analogous organs, for example, wing of bird and wing of 
butterfly, organs differing entirely in structure, but performing 
the same function. 
Remak (1850) described ‘three germinal layers,” and Huxley 
(1859) homologizes them in the lower animals. 
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