582 



GENERAL CONSIDERATIONS 



Animal," published in 1817, which influenced classification for some 

 time. He did not accept the classification outlined by Linnaeus but 

 presented one dividing the animal kingdom into four branches, Verte- 

 brata, Mollusca, Articulata, and Radiata. Cuvier (Fig. 398) believed 

 in the theory of special creation and explained the existence of dissimilar 

 fossils in different rock strata as evidence of a series of creations, the life 

 arising from each past creation being destroyed completely by some great 

 catastrophe. This theory is known as catastrophism ; the opposite view — 

 that geological succession has been a continuous process — is known as 



Fig. 398. — Georges Cuvier, 1769-1832. (From Shull, "Principles of Animal Biology," 

 after Locy, "Biology and Its Makers," and by the courtesy of McGraw-Hill Book Company, 

 Inc.) 



uniformitarianism. Cuvier was followed by Owen (1804-1892), a great 

 English physician and anatomist, to whom we owe the ideas of homology 

 and analogy. The founder of the modern science of histology was Bichat 

 (1771-1802), a French anatomist and physiologist. 



629. Physiology. — The Greeks believed in spirits and humors in the 

 body and in the existence of the pneuma which, taken into Latin became 

 spiritus, equivalent to vital force. Harvey contributed to physiology 

 by applying to it the experimental method. During the sixteenth and 

 seventeenth centuries two schools of physiologists arose, one seeking to 

 put the subject on a chemical foundation, the other to base it on physics. 

 Johannes Miiller (1801-1858), a German, for the first time brought to 

 bear on physiology not only the facts of chemistry and physics but also 



