INTRODUCTION. 11 



Thus then it stands absorption, assimilation, exhalation, 

 development and generation are functions common to all liv- 

 ing bodies ; birth and death the universal limits of their exist- 

 ence ; an areolar, contractile tissue, containing within its laminsa 

 fluids or gases in motion, the general essence of its struc- 

 ture ; substances almost all susceptible of conversion into fluids 

 or gases, and combinations capable of an easy and mutual 

 transformation, the basis of their chemical composition. Fixed 

 forms that are perpetuated by generation distinguish their 

 species, determine the complication of the secondary functions 

 proper to each of them, and assign to them tlie parts they are 

 to play on the great stage of the universe. These forms are 

 neither produced nor changed by their own agency life sup- 

 poses their existence, its flame can only be kindled in an 

 organization already prepared, and the most profound medita- 

 tion and lynx-eyed and delicate observation can penetrate no 

 farther than the mystery of the pre-existence of germs. 



Division of Organized Beings into Animals and Vegetables. 



Living or organized beings have always been subdivided 

 into animate beings^ that is, such as are possessed of sense and 

 motion, and into inanimate bei?igs, which are deprived of 

 both these faculties, and are reduced to the simple faculty of 

 vegetating. Although the leaves of several plants shrink 

 from the touch, and the roots are steadily directed towards 

 moisture, the leaves to light and air, and though parts of 

 vegetables appear to oscillate without any apparent external 

 cause, still these various motions have too little similarity to 

 those of animals, to enable us to find in them any proofs of 

 perception or will. 



The spontaneity in the motions of animals required essen- 

 tial modifications even in their purely vegetative organs. 

 Their roots not penetrating the earth, it was necessary they 

 should be able ^to place within themselves a supply of aliment, 

 and to carry its reservoir along with them. Hence is derived 

 the first character of animals, or their alimentary canal, from 



