DIVISION II. 



THE STRUCTURE OP THE PLANT AND 

 OFFICES OF ITS ORGANS. 



CHAPTEE I. 



GENERALITIES. 



We have given a brief description of those elements 

 and compounds which constitute the plant in a chemical 

 sense. They are the materials — ^the stones and timbers, 

 so to speak — out of which the vegetable edifice is built. 

 It is important, in the next place, to learn how these 

 building materials are put together, what positions they 

 occupy, what purposes they serve, and on what plan 

 the edifice is constructed. 



It is impossible for the builder to do his work until he 

 has mastered the plans and specifications of the archi- 

 tect. So it is hardly possible for the farmer with cer- 

 tainty to contribute in any great, especially in any new, 

 degree, to the upbuilding of the plant, unless he is 

 acquainted with the mode of its structure and-the ele- 

 ments that form it. It is the happy province of science 

 to add to the vague and general information which the 

 observation and experience of generations have taught, 

 a more definite and particular knowledge, — a knowledge 

 acquired by study purposely and carefully directed to 

 special ends. 



An acquaintance with the parts and structure of the 

 plant is indispensable for understanding the mode by 

 which it derives its food from external sources, while the 

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