IV. THE FUNCTIONS AND COMPOSITION OF LIVING 



THINGS 



Problems. — To discover the functions of living matter. 



(a) In a living plant. 



(b) In a living animal. 



Laboratory Suggestions 



Laboratory study of a living plant. — Any whole plant may be used ; 

 a weed is preferable. 



Laboratory demonstration or home study. — The functions of a living 

 animal. 



Demonstration. — The growth of pollen tubes. 



Laboratory exercise. — The growth of the mature ovary into the fruit, 

 e.g., bean or pea pod. 



To the Teacher. — The object of this chapter is first to give the child a pre- 

 liminary or pre-view of the larger problem outlined in the six following chapters, 

 i.e., plant growth and nutrition. Then the concept of the cell as a unit of structure 

 should be worked out and the very important notion of fertilization in its relation 

 to the development of the plant. Problems 17, 18, 19, and 20 might well follow 

 Chapter II, if the teacher desires, and the problems on fertilization introduced after 

 that of the structure of the flower. Experience has shown the sequence here 

 followed, however, to work out well. 



Any simple plant or animal tissue can be used to demonstrate the cell. Epider- 

 mal cells may be stripped from the body of the frog or obtained by scraping the 

 inside of one's mouth. The thin skin from an onion stained with tincture of iodine 

 shows well, as do thin cross sections of a young stem, as the bean or pea. One of the 

 best places to study a tissue and the cells of which it is composed is in the leaf of a 

 green water plant, Elodea. In this plant the cells are large, and not only their out- 

 line, but the movement of the living matter within the cells, may easily be seen, and 

 the parts described in the next problem can be demonstrated. 



Problem 17: The uses of the parts of a plant. 

 Materials. — Growing plants, seedlings, and red ink. 



NOTE. — A growing plant has roots, stems, leaves, flowers, and fruits. 



Method and Observations. — Locate each part in the specimen 

 before you. If you water a growing plant that is badly wilted, 



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