230 THE FITNESS OF THE ENVIRONMENT 



It must not be forgotten that the share of 

 the organism in such processes is also impor- 

 tant. If possible, the smoothness with which 

 chemical reactions are carried out in the leaf, 

 perhaps quite without any stop at the formal- 

 dehyde stage, and the certainty with which 

 definite substances in large amounts instead 

 of mixtures in very small amounts are pro- 

 duced, seem more remarkable than the under- 

 lying chemical facts. Needless to say, one 

 great factor in such processes is the action of 

 enzymes. Otherwise we are at a loss for a 

 description of the ways and means by which 

 the organism operates, though the brilliant 

 studies of chlorophyll which have recently 

 been carried out by Willstatter promise great 

 achievements in the future. 1 

 v . f The underlying chemical facts, however, 

 remain ; carbohydrates are among the natural 

 products of carbon dioxide and water; they 

 manifest in solution, especially in such con- 

 ditions as obtain in protoplasm or the ocean, 2 

 unparalleled instability and variety of reac- 

 tions ; and they produce spontaneously an 

 enormous number of very active chemical 

 substances. It is easy to see that, given 



1 See his many papers of recent years in "Liebig's Annal- 

 len." 



2 Henderson, Journal of Biological Chemistry, X, 3, 1911. 



