INTRODUCTION. 45 



In this case each fragment seems to possess all the parts 

 of the whole animal, each having the generative and nu- 

 tritive power perfect; there then seems to be no necessity 

 that any of these parts should die. 



But let a section be made in what is called the eye or 

 germ of these animals, and death is as certain as in the 

 higher order; for here the chain of dependency among the 

 several parts, making each fragment, as it were, complete 

 in itself, is broken, and this essential element to organic 

 existence as certainly destroyed. 



In the inorganic body we observe no such dependency 

 among its several parts. Each can preserve its existence 

 as well when separated from all the other parts and from 

 the whole body as when united. 



The eighth element of organization is a limited duration. 



Death is the eternal fiat stamped upon all living, or- 

 ganic bodies they carry on their functions for a definite 

 period of existence only, during the active and early exer- 

 cise of which, the body grows, attains maturity, and then 

 begins to languish, decay and die. 



Inorganic bodies, on the other hand, have no fixed pe- 

 riod of duration their existence can be terminated at any 

 moment, either by mechanical violence breaking down their 

 several parts, or by the play of chemical affinity destroy- 

 ing their nature, or if none of these circumstances operate, 

 their duration may be unlimited. 



These are the different elements which are regarded as 

 the most essential in forming organization. 



We now proceed to notice the principal of those most es- 

 sential in preserving organization which consist of, 



1. Atmospheric air. 3. Water. 



2. Food. 4. Heat. 



These elements are the vital stimuli, whose presence is 

 indispensable to the existence of all kinds of organization, 

 whether animal or vegetable. 



In the higher order of animals, the necessity of breath- 



