243 HOW CEOPS GEOW. 



4 



ingenious methods of propagation practiced in fruit- and 

 flower-culture are only intelligible .by the help of this 

 knowledge. 



Oeganism of the Plant. — "We have at the outset 

 spoken of organic matter, of organs and organization. 

 It is in the world of life that these terms have their fit- 

 test application. The vegetable and animal consist of 

 numerous parts, differing greatly from each other, but 

 each essential to the whole. The root, stem, leaf, flower 

 and seed are each instruments or organs whose co-oper- 

 ation is needful to the perfection of the plant. The 

 plant (or animal) being thus an assemblage of organs, is 

 called an Organism; it is an Organized or' Organic 

 Structure. The atmosphere, the waters, the rocks and 

 soils of the earth, do not possess distinct co-operating 

 parts ; they are Inorganic matter. 



In inorganic nature, chemical aflQnity rules over the 

 transformations of matter. A plant or animal that is 

 dead, under ordinary circumstances, soon loses its form 

 and characters ; it is gradually consumed, and, at the ex- 

 pense of atmospheric oxygen, is virtually burned up to 

 air and ashes. 



In the organic world a something, which we call 

 Vitality, resists and overcomes or modifies the afiQnities 

 of oxygen, and insures the existence of a continuous and 

 perpetual succession of living forms. 



An Organism or Organized Structure is characterized 

 and distinguished from inorganic matter by two par- 

 ticulars : 



1. It builds up and increases its own mass by appro- 

 priating external matter. .It absorbs and assimilates 

 food. It grows by the enlargement of all its parts. 



2. It reproduces itself.* It develops from a germ, and 

 in turn gives origin to new germs. 



Ultimate and Complex Organs. — In our account 

 of the Structure of the Plant we shall first consider the- 



