SPRING NATURE STUDY. 599 



LESSON IX. MORE WORK FOR THE LEAVES. THROWING 

 OUT WATER. 



Repeat or review the experiments suggested, showing 

 that the roots drink in water with food dissolved in it, and 

 that this is carried through the stem to the leaves. The 

 roots must take in water every day, to get food for the 

 plant. What becomes of the water ? 



Invert a clean dry fruit-can closely over a bean plant. 

 Set the plant in the sunlight. Before very long the inner 

 surface of the can becomes covered with moisture or water. 

 If the leaves are removed, or the plant is not in the sun- 

 light, little water will be seen. 



The following simple experiment, from Goodale's "Physi- 

 ological Botany," will help the children to see and under- 

 stand what the leaves do : 



" Take six or eight fresh, large, healthy leaves, two 

 tumblers filled to within an inch of the top with water, 

 two empty, dry, clean tumblers, and two pieces of card, each 

 large enough to cover the moufch of the tumbler. Near the 

 middle of each card, bore three or four holes, each large 

 enough to allow the stalk of a leaf to pass through. Put 

 the leaf-stalks through the holes, far enough to hang quite 

 deep in the water, turn the empty tumblers upside down, 

 one over each card, so as to cover the broad part or blade 

 of the leaves. Place one pair of tumblers in the sunlight, 

 the other in a shady place. In five or ten minutes examine 

 the inverted tumblers." 



Thus the pupils will learn that one part of the work of 

 the leaves is to throw out the water which the roots take 

 in. The microscope shows us that each leaf has, mainly 

 on its lower surface, thousands of little pores or mouths, 

 much too small to be seen by the eye (each apple leaf is 

 said to have about one hundred thousand of these pores), 

 through which water passes. 



