128 RELATIONS OF MAN WITH EXTERNAL NATURE. 



Without such organic vital action, perhaps the development of organ- 

 izable substance is not conceivable, certainly not that of organized 

 structure ; and hence it is, that the mind is driven to the assumption 

 or inference that some peculiar force, superadded to the inorganic 

 forces of nature, is here in action. Now, inorganic bodies have no 

 such structure; not even a crystal exhibits it when examined by the 

 eye or by the microscope; its substance, even to the minutest mole- 

 cule, is homogeneous, although a few examples occur of crystallized 

 bodies, such as ice, having minute drops of fluid or gaseous matter 

 confined in little chasms in their interior. But inorganic bodies, 

 generally are composed either of solid, liquid, or aeriform matter, the 

 particles of which are simply held together or are intermingled. 



The heterogeneous composition or structure of organic bodies, as 

 compared with the homogeneous substance of the molecules of in- 

 organic bodies of the most regular form, such as crystals, is connected 

 with the tendency and necessity of the former, during their life, to 

 undergo ceaseless internal motion, and constant change; whilst the 

 latter, when once formed, may remain unchanged for an indefinite 

 period of time. The inmost substance of an organic body continually 

 suffers those changes changes of absorption and assimilation of new 

 material, and removal of old material which constitutes the very 

 essence of vital action; whilst the material of an inorganic body, so 

 long as it preserves its individuality, continues unaltered. An or- 

 ganic body is nourished and grows; an inorganic body merely in- 

 creases in size. The nutrition and growth of an organic body, are 

 accomplished by an interstitial process of waste and repair, and by 

 evolution of new elementary parts, both processes depending upon 

 a deposit and accretion of new selected material around or within each 

 elementary constituent of its organized structure, or, as it has been 

 said, by intussusception; whilst, on the other hand, the inorganic body, 

 whether crystalline or non-crystalline, simply increases by the juxta- 

 position or superaddition of like matter upon its surface, i. e., by an 

 accretion to its general or external surface only. 



Organic bodies possess, in their perfect condition, powers which are 

 only called into activity by stimuli, under the influence of which they 

 react, as in the case of the germ, or seed. These powers do not last 

 indefinitely; but they may remain dormant for a long period, even for 

 thousands of years, in the case of seeds, without being extinguished. 

 Inorganic bodies retain their own properties, however, for indefinite 

 periods. 



Organic bodies, manifesting life, are subject to the conditions of 

 health and disease. Moreover, their duration is limited; the individ- 

 ual animal or plant, however complex, or however simple, ultimately 

 dies; whilst inorganic bodies either remain unchanged, enduring in- 

 definitely, or, if they undergo decomposition, it is in order that their 

 elements may assume conditions of more perfect stability. 



To maintain the continued presence, on the earth, of organic bodies, 

 which, subject as they are to individual death, have a limited dura- 

 tion, the reproduction of the species is provided for. Hence the last 

 characteristic of organic bodies, as compared with inorganic, is this : 



