ON THE 



CONFORMATION, CLASSIFICATION, AND GEOGRAPHICAL 

 DISTRIBUTION OF ANIMALS, 



CONSIDERATION OF THE GENERAL PLAN FOLLOWED BY 

 NATURE IN THE ORGANIZATION OF ANIMALS. 



344. The object of the present section is to examine the 

 plan agreeable to which each animal is formed, and to observe 

 how life is modified in the various classes of these beings. 



345. Nothing is more varied than the conformation of 

 the various animals which people the surface of the earth ; 

 and there exists no less diversity in the various acts by which 

 life is manifested in these animal machines. In some the 

 functions are few, and the sphere of their physiological 

 activity very restricted ; in others the faculties are extremely 

 varied, and their actions multiplied in the highest degree ; 

 and to express this difference in the nature of animals, it is 

 usual to say that some are more elevated, more perfect, than 

 others. In this way and in this view we say that a fish is 

 more elevated in the animal scale than an oyster ; a dog 

 more than a fish ; a man more so than the dog. 



346. Tendency to the Localization of Functions, and 

 to the Division of the Physiological Phenomena. The prin- 

 ciple which nature seems to have adopted in the perfecting 

 of animals, is one which has been found to exercise the most 

 beneficial influence over human progress ; it is, the division 

 of labour. Thus, when we compare animals with each other, 

 differing in the number and extent of their faculties, we shall 

 find that the perfecting of these beings coincides with a 

 localization more and more marked in their functions : when 

 the same instrument serves for the production of several 

 phenomena, the physiological result is, as it were, gross and 

 imperfect ; and an organ always performs its part better as it 

 is more specialized. Now the mode of action of an organ or 

 instrument, in the sense we allude to, depends always on its 

 intimate nature, or its structure, and other qualities ; and 



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