TH E COLOR CHANGE 



ent substances. Our chlorophyll, then, was a 

 mixture of at least two substances, or more 

 likely a chemical compound which broke into 

 two of its constituent compounds, the yellow 

 one being called xanthophyll. 



** This separation presumably occurs when 

 green leaves turn yellow as is suggested by this 

 simple experiment. If our alcoholic extraction 

 from Elm leaves has not been kept in darkness, 

 and sealed from the oxygen of the air, it has 

 rapidly decomposed, turning from green to 

 yellow — that is, the green constituent fades 

 away first, gradually revealing the yellow one." 



The Seventh Report of the Forest, Fish, and 

 Game Commission of the State of New York 

 notes that Alfred Russel Wallace, an English 

 scientist, states that chlorophyll is not a simple 

 green substance, but that it really consists of 

 at least seven distinct substances, varying in 

 color from blue to yellow and orange, and that 

 these differ in their proportions in the chlo- 

 rophyll of different plants. Moreover, they have 

 different chemical reactions, are differently af- 



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