solved by the alcohol, which has become an intense green. This 

 green coloring matter is dissolved chlorophyll. Save this leaf 

 for a future experiment. 



In the living plant this chlorophyll or leaf-green is scattered 

 throughout the green tissues in little oval bodies, and these 

 bodies are most abundant near the upper surface of the leaf, 

 where they can secure the greatest amount of light. Without 

 this green coloring matter, there would be no reason for the 

 large flat surfaces which the leaves possess, and no reason for the 

 fact that the leaves are borne most abundantly out at the ends of 

 branches where the light is most available. 



5. Plants grown in darkjiess are yellow a7id slender, a7id do not 

 reach 7naturity. — Compare the potato sprouts which have grown 

 from a tuber lying in the dark cellar with those which have 

 grown normally in the bright light. The shoots from the cellar 

 are yellow and slender. They have reached out for that 

 which they cannot find ; and when the carbon which is stored in 

 the tuber is exhausted, these shoots will have lived useless lives. 



A plant which has been grown in darkness from the seed will 

 complete its life even in its infancy, although for a time the 

 little seedling wall grow very tall and slender. Light makes pos- 

 sible the production of this green color ; and it is evident that 

 the light and this green color together have to do with the utiliz- 

 ation of the carbon dioxid of the air. 



6. Carbon dioxid is absorbed by the leaf during; sunlight, and 

 oxygen is given off. — Some proverbs are founded on facts. It is 

 true that plants purify the air during the day. Under the influ- 

 ence of sunlight and the green color of the foliage, the carbon 

 dioxid which enters into the leaf is absorbed by the living parts, 

 and with this absorption of carbon dioxid there is given off 

 ox3^gen, which is necessar}^ at all times to sustain life. 



Very careful experiments have shown that carbon dioxid is 

 absorbed and that oxygen is given off by all green surfaces 

 during the hours of sunlight. How this carbon dioxid which 

 is thus absorbed may be used as food is a question of much in- 

 terest. 



7. Chlorophyll absorbs the heat of the sim's rays, and the 

 energy thus obtained is used by the living fnatter in unitijig 



