THE NATUEE MD WOEK OF PLANTS 



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I. THE COMPOSITION AND PURPOSES OF 

 PLANTS 



1. The plant is composed of living matter. — The 

 tints of a flower, the graceful curves of a twining 

 vine, and the uncouth forms of the cactus claim our 

 attention, because they excite our curiosity and 

 admiration. These and many other features of the 

 vegetable world become of much greater interest, 

 however, when it is learned that the color of the 

 rose, the lacelike fronds of the fern, the imposing 

 trunk of the forest tree, the spines of the thistle, 

 and the juicy sweetness of a berry are all due to the 

 action of a wonderful substance, which is known 

 to be living, and is usually termed protoplasm. If 

 our studies are extended, we may learn that this liv- 

 ing substance is the most important part of our 

 bodies, as well as those of all other animals and of 



