CHAPTER II 



SEAWEEDS AND LEAF-GREEN 



The major planet Earth probably differs from all its 

 companions in space in one special respect. 



It is a "green" world, and this colour is no acci- 

 dental ornament, but is the real fountain and origin of 

 all the life that swarms upon its surface. 



Not only the growth of plants, but all animal and 

 human activities — the soaring of a hawk, logical 

 reasoning, or any kind of mental or emotional strain 

 — depend upon this peculiar green substance "chloro- 

 phyll." 



One cannot exactly say that the world depends upon 

 chlorophyll in the way that a motor is " run " by petrol, 

 for this chlorophyll may not be used up in the process. 

 It is a sort of chemical sensitiser which absorbs certain 

 kinds of sunlight. That is, the energy of their vibra- 

 tions is intercepted and turned to another form of 

 work. 



Our food, which is necessary for every strain of nerve 

 or muscle, consists of animal and vegetable matter, 

 and this last represents the life-work of chlorophyll or 

 "leaf green." 



We cannot give more than a very general idea of the 

 way in which the chlorophyll works. The coolness and 

 shade under a beech tree even in very hot weather is 

 enough to show that the leaves have somehow inter- 

 cepted most of the sunlight. To follow the process a 

 httle more closely, one must imagine a leaf with the 



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