82 MANtJAI, OF NATURE STUDY. 



have some important work to do, or else it must 

 contain in store something of infinite value to the 

 plant ; otherwise it would not go to the trouble of 

 constructing these stomata through the epider- 

 mis, thus making thoroughfares, or gateways, con- 

 necting the inner green mass with the outside world. 

 Why does the detached leaf wither when exposed 

 to dry air or sunlight? Try the experiment to see 

 that such a result is true. Why do corn leaves 

 curl up during the heat of the day in dry weather, 

 and open out again at night ? Invert a tumbler or 

 glass fruit jar over a bunch of fresh leaves, and in 

 a few minutes observe the moisture collected on 

 the inside of the vessel. Where did the moisture 

 come from? Can you now see any use for the 

 pores of the epidermis? Why do plants look so 

 bright and green after a warm spring rain ? Do 

 the stomata have anything to do with it? How? 



We have already learned that root hairs draw 

 moisture out of the soil, and with the moisture all 

 dissolved substances, the water serving chiefly as a 

 carrier, or vehicle, for conveying material to the aid 

 of the seed factory. 



We also learned that the villi of our elementary 

 canal opened their mouths just wide enough to 

 drink the dissolved portion of our food, the water 

 or liquid serving as a carrier for the food that could 



