VIII. 

 CHLOROPHYLL AND GROWTH.* 



The adult leaf manufactures about ninety- 

 seven per cent of the food of the plant from 

 water and carbon dioxide of the air. In the 

 study of its functions and development it is 

 of the greatest importance to know whether 

 the plant can build up a leaf from food stored 

 within its body, or the products of other 

 leaves, or whether the products of the ma- 

 turing leaf itself are necessary to enable it to 

 complete growth. 



In recognition of this fact it was one of the 

 earlier questions taken up in the study of the Historical 

 physiology of the plant, and it has engaged 

 the attention of a number of authors of the 

 first rank. It would not be possible to recount 



*Adapted from a lecture on "The Relation of the Growth of 

 Leaves and the Chlorophyll Function" before the Linnean So- 

 ciety of London, June 18. 1896. 



