60 THE NATURE AND WORK OF PLANTS 



67. Characteristics of chloi^ojyhyl. — Chloropb.yl is 

 absolutely indispensable for the formation of food in 

 the leaf, and it will be important to extract some of 

 it from a leaf and ascertain its qualities. To do this 

 place a. number of leaves, that have been cut up into 

 small pieces or bruised, in a bottle or tumbler and 

 cover with alcohol. Close the vessel and set away 

 in a dark place for a day. Pour off some of the 

 liquid into a wine-glass or small test tube. Hold up 

 to the light. The solution appears to be of a bright 

 emerald green. Now hold the glass in direct sun- 

 light and look at the edge of the liquid. If held 

 properly, it will show a blazing red appearance. 

 Chlorophyl has the power of making such changes 

 in sunlight that it appears red; it affects light in 

 other ways also. 



68. S2:)ectrum of chlorophyl. — If the study of 

 chlorophyl were continued in the physical labora- 

 tory, it could be seen that if light which has passed 

 through a solution of chlorophyl is spread out on a 

 screen by means of a prism of glass, some of the 

 colors of the artificial rainbow will be missing. The 

 missing parts will comprise the blue, violet, and most 

 of the red rays. Chlorophyl, in the living plant, ab- 



