A YEAE IN SCIENCE 79 



cell? What is their arrangement? These small bodies 

 contain a green substance known as chlorophyll and 

 for that reason they are called chloroplasts (chloro 

 menus green; plattein, to form). Within the cell there 

 is an almost colorless, jelly-like substance known as 

 protoplasm. This is the living part of the cell. It is 

 somewhat granular in appearance. Upon careful exam- 

 ination you may be able to see it. 



Exercise 49. Making of Food for Plants. 

 Object: The relation of chlorophyll to starch forma- 

 tion. 



Apparatus 



Variegated ^cranium Iodine 



Alcohol Beaker 



Bunsen burner Evaporating dish 



Corn starch 



Directions: Place a small amount of corn starch in 

 an evaporating dish and pour a drop of iodine over it. 

 What color does the starch turn? If, when iodine is 

 placed on a substance, its color turns to a blue-black, 

 starch is present. 



Place a geranium with variegated colored leaves in 

 the bright sunlight for the greater portion of a day. 

 Select a few leaves on the plant and sketch the blades 

 to show the color patterns on them. Remove these 

 leaves and immerse them immediately into boiling 

 water to kill them. After five minutes boiling, place 

 the leaves in a vessel of 96% alcohol to extract the 

 chlorophyll. When the leaves become white, spread 



