OEGAITS OF THE PLANT. 221 



it derives its food from external sources, while the ingen- 

 ious 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 fittest 

 application. The vegetable and animal consist of numer- 

 ous parts, differing greatly from each other, but each essen- 

 tial to the whole. The root, stem, leaf, flower, and seed, 

 are each instruments or organs whose co-operation is need- 

 ful to the perfection of the plant. The plant (or animal), 

 being thus an assemblage of organs, is called an Organism/ 

 it is an Organised or Organic Structure. The atmos- 

 phere, the waters, the rocks and soils of the earth, are 

 mineral matters ; ,they are inorganic and lifeless. 



In inorganic nature, chemical afiinity 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 by the atmospheric 

 oxygen, and virtually burned up to air and ashes. 



In the organic world a something, which we call the 

 'Vital Principle, resists and overcomes or modifies the af- 

 finities of oxygen, and ensures the existence of a con- 

 tinuous and perpetual succession of living forms. 



The organized structure is characterized and distinguish- 

 ed from mineral matter by two particulars : 



1, It builds up and irfcreases its own mass by appropri- 

 ating external matter. It assimilates surrounding sub- 

 stances. It groios by the absorption of food. 



2t It reproduces itself. It comes from, and forms again 

 a seed or germ. 



Ultimate and Complex Organs. — In our account of 

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

 ments of that structure — the Primary Organs or Vegetable 

 Cells — which cannot be divided or wounded without ex- 



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