PLANT DEVELOPMENT 



autumn foliage, are to be regarded as the ulti- 

 mate useless residue after the withdrawal of 

 the transformed cholorophyl corpuscles." 



He calls attention to a coloring material in 

 the leaves named anthocyanin which serves a 

 very curious purpose, keeping itself between 

 the food particles that are traveling back to 

 their winter home in the trunk and roots of 

 the trees, thus forming a screen or awning, as 

 he calls it, between the foods and the sun, a 

 protective agent against injurious light rays. 

 Certain acids combined with this coloring 

 material produce the various colors of the 

 autumn leaves, the coloring material appearing 

 in great abundance when the leaves have about 

 ended their life. 



The green color of the foliage, which is 

 caused by the chlorophyl he refers to, takes 

 on a new and vital interest in the light of 

 modern days. It comes to the farmer with a 

 strange sense of unreality, this thought that 

 the green of the splendid sweep of the waving 

 corn is practically that which keeps his own 

 lungs in action, for it is from the iron com- 

 pounds that the chlorophyl is in part produced, 

 the green of the fields and forests, just as it is 



73 



