COMPARISON BETWEEN ANIMALS AND PLANTS. 245 



ters of organization; that it seems impossible to distinguish them by 

 any trait that belongs exclusively to either ; that the connexion be- 

 tween them appears the most striking in the least perfect species of 

 both kingdoms ; and that as we recede from this point, the differ- 

 ences become more numerous and more marked. 



We may illustrate this view, by imagining two ascending cnains, 

 rising from one common point, each side of the chain becoming 

 more and more unlike in proportion to the intervening distance 

 from the centre. From this same central point, also proceeds the 

 chain of inorganized substances ; some imperfect animals resem- 

 bling plants in their outward form, some, both of animals and plants, 

 resembling minerals in their hard and calcareous coverings and 

 shapeless forms. 



Having thus learned the almost imperceptible gradations by which 

 the animal and vegetable kingdoms are blended, we must, in stating 

 the important differences which exist between animals and plants, 

 consider the imperfect species of both kinds as exceptions to any- 

 general rule, and confine ourselves to perfect animals and plants. 



1st. Plants differ from, animals with respect to the elements which 

 compose them; carbon, hydrogen, and oxygen, form the base of vege- 

 table substances ; animals exhibit the same elem,ents, with this impor- 

 tant distinction, that carbon prevails in plants, and nitrogen in ani- 

 mal food. 



2d. They differ in their food ; plants are nourished with inorgan- 

 ized matter, absorbed with water, xchich holds in solution various s^tb- 

 stances; animals are mostly nourished either by vegetable or other 

 animals. 



3d. Plants throw off oxygen gas, and inhale carbonic acid; ani- 

 mals, in respiration, inhale oxygen gas and throw off carbonic acid. 



4th. Although plants and animals both possess a principle of life, it 

 is in the one case much more limited than in the other ; exhibiting itself 

 in plants by a feeble power of contraction or irritability ; in animals 

 appearing in sensation,^ muscidar movem,ent, and voluntary motion. 



We see, then, many important differences between perfect animals 

 and perfect plants. We have, in numerous instances, pointed out 

 striking analogies between the two great divisions of organized bod- 

 ies : this subject might be greatly enlarged ; but we have alreadyj 

 amid the multitude of interesting facts and reflections presented by 

 the vegetable creation, far exceeded the bounds originally prescribed. 

 A few remarks on the inorganic matter upon and around the earth, 

 and our course of Lectures is closed. 



Inorganic bodies form the solid base of the globe. Minerals are 

 spread upon the face of the earth, or lie buried beneath its surface. 

 They form vast masses of rocks, chains of mountains, and the 

 ground upon which we tread. The Water occupies a still greater 

 surface of the earth than the land ; it is filled with life and animation ; 

 the treasures and wonders of the deep seem almost unbounded. 

 The Air, lighter than earth and water, extending on all sides about 

 forty miles in height, surrounds the whole globe, separating us from 

 the unknown elements which exist beyond it. Heat, or Caloric, is a 

 subtle fluid which pervades all matter, in an increasing proportion 

 from solids to fluids, and fluids to gases. Light, reflecting its hues 

 from terrestrial objects, produces, by the decomposition of its rays 

 all the beautiful variety of colouring. 



Result of the comparison between animals and vegetables— Chains of beings 

 proceeding from one point— Differences between animals and plants— Different liinas 

 of inorganic matter— The Deity manifested in his works. 

 21* 



