INTRODUCTION. 



GENERAL CONSIDERATIONS ON ANIMAL AND VEGETABLE 

 LIFE. 



If we cast a glance at the immense quantity of animals 

 and plants which livp on the surface of our globe, we are 

 at first struck with the variety of forms under which they 

 present themselves, with their colors so diversified and 

 sometimes so brilliant, and with the coUossal proportions 

 of some, as compared with the diminutiveness of others. 

 But when, after this superficial examination, we study 

 them more attentively ; when we examine with care the 

 structure of each being, we at once see the perfection 

 which exists in its organs, and how well they are adapted 

 to its peculiar habits and mode of life — from the enor- 

 mous whale, which requires an ocean to swim in, to 

 those minute and myriad forms which find ample room 

 for all their evolutions in a single drop of its waters ; 

 from the lofty tree which has stood for centuries, an 

 ornament in the midst of the landscape, to the lowly 

 flower which attracts us by its beauty and fragrance — all 

 form a collection of objects whose framework is constructed 

 in the most admirable manner, and whose vital manifesta- 

 tions are in the highest degree instructive and interesting. 



At first sight, nothing would seem to be more widely 

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