The Nature of Plants 9 



of the moisture which has come up from the roots es- 

 capes. (Exp. 7.) It is a mistake to think that leaves 

 absorb moisture from the air (Fig. 9). 



The green coloring matter which forms in the leaves The 

 as soon as they come above ground is called " chloro- ^hhrop^hyll 

 phyll." It is with the aid of the chlorophyll that 

 carbon dioxid from the air is combined with water in 

 the leaves to form starch and sugar which nourish the 

 plant. Animals as well as plants need carbon, but ani- How 

 mals, having no chlorophyll, cannot take carbon from dependent 



the air. They must get it from the plants. Plants take 

 crude materials from earth, air, and water, and make existence 

 them into substances that animals can use as food. 

 They stand between us and the mineral kingdom, 

 preparing from crude minerals food suitable for us. 



During the process of food manufacture, surplus Gases that 

 oxygen is given off through the stomata. At night this pS{ r m 

 action ceases, since light as well as chlorophyll is neces- 

 sary for the manufacture of food. Then the plant gives 

 off carbon dioxid instead of oxygen. A case is on record 

 of a man being suffocated by this gas while sleeping 

 at night in a poorly ventilated greenhouse. 



If the light is cut off from a green plant, it loses its How plants 

 chlorophyll, bleaches white, and eventually dies for lack J^^JL 

 of food. (Exp. 8.) An example of this is often seen in chlorophyll 

 grass that has been covered with a board for a few days. 

 If the board is taken away in time, the grass soon re- 

 gains its natural color and resumes its growth. Plants 

 that have no chlorophyll, like mushrooms and Indian 

 pipe, lack the green color of ordinary plants. They 

 have no power to use the carbon dioxid of the air in the 



