LINN-EUS AND NATURAL HISTORY 133. 
being founded upon an analysis of structure, was important. 
It was directly at variance with the idea of scale of being, and 
overthrew that doctrine. 
Cuvier first expressed these views in a pamphlet published 
in 1795, and later in a better-known paper read before the 
French Academy in 1812, but for the full development of 
his type-thcory we look to his great volume on the animal 
kingdom published in 1816. The central idea of his arrange- 
ment is contained in the secondary title of his book, “The 
Animal Kingdom Arranged According to its Organization ” 
(Le Régne Animal Distribué d’aprés son Organisation, 1816). 
The expression ‘‘arranged according to its organization” 
embraces the feature in which this analysis of animalsdiffers 
from all previous attempts. 
Correlation of Parts.—An important idea, first clearly 
expressed by Cuvier, was that of correlation of parts. The 
view that the different parts of an animal are so correlated 
that a change in one, brought about through changes in use, 
involves a change in another. For illustration, the cleft hoof 
is always associated with certain forms of teeth and with the 
stomach of a ruminant. The sharp claws of Hesh-eating 
animals are associated with sharp, cutting teeth for tearing 
the flesh of the victims, and with an alimentary tube adapted 
to the digestion of a fleshy diet. Further account of Cuvier 
is reserved for the chapter on the Rise of Comparative Anat- 
omy, of which he was the founder. 
Von Baer.—The next notable advance affecting natural 
history came through the work of Von Baer, who, in 1828, 
founded the science of development of animal forms. He 
arrived at substantially the same conclusions as Cuvier. 
Thus the system founded upon comparative anatomy by 
Cuvier came to have the support of Von Baer’s studies in 
embryology. 
The contributions of these men proved to bea turning- 
