HISTORICAL DEVELOPMENT OF ZOOLOGY 445 



Thomson points out, White was " the prototype of the better 

 class of modern amateurs," still the out-of-door study of ani- 

 mals "rarely attained either dignity or definiteness until 

 Darwin demonstrated its importance." 



Animal electricity was discovered by Galvani (1737-1798), 

 professor of anatomy at Bologna. His attention is said to 

 have been called to the subject by his wife. She was prepar- 

 ing frogs' legs for the table near an electric machine in opera- 

 tion, and noticed that when the legs were touched by the 

 knife they twitched violently. 



Zoology of the Nineteenth Century. The science of zoology 

 developed so rapidly from the beginning of the eighteenth 

 century that it will be impossible now to do more than call 

 attention to a very few of the most important discoveries and 

 the men to whom they are accredited. A dominating figure 

 in the early part of the nineteenth century was Georges Cuvier 

 (1769-1832), a French naturalist whose influence was exerted 

 along many different lines. By his studies of fossils, recog- 

 nizing them as the remains of animals of past times, and 

 related to the animals of to-day, he founded paleontology. 

 He also stated the principle of the correlation of parts, 

 a conception which pictures the animal as a unit rather 

 than a fortuitous collection of separate parts. While he un- 

 doubtedly carried the principle beyond its legitimate limits, 

 there can be no question as to its important influence on 

 the history of zoology. Cuvier recognized the importance 

 of anatomical structure as a basis for classification. He also 

 knew a second basis in paleontology, a fact just referred to. 

 Cuvier divided the animal kingdom into four groups, Ver- 

 tebrata, Mollusca, Articulata, and Radiata. 



During the nineteenth century important discoveries paved 

 the way for a better understanding of the minute structure 

 of the animal body and the physiology of its units of struc- 

 ture, the cells. In 1838 Schleiden showed that plants were 



