THE SEEDLING AND YOUNG PLANT 87 



means of the energy thus derived from the sun, the mole- 

 cules of carbon dioxide and water are broken up in the 

 meshes of this chlorophyll corpuscle, and experiments 

 prove that the chlorophyll substance plays the part of the 

 ' trap to catch a sunbeam.' We are not concerned with 

 the hypothetical explanations offered for all the details 

 of this remarkable process, but the present position of 

 science enables us to say that, be these what they may, 

 the chlorophyll corpuscle gains energy form the sun, and 

 brings this energy to bear on the carbon dioxide and 

 water in such a way that it does work in tearing 

 asunder their molecules in the substance of the cor- 

 puscle. Then a curious series of results follows. The 

 carbon, oxygen, and hydrogen undergo new rearrange- 

 ments, which amount finally to this the substance 

 known as starch, and consisting of carbon, hydrogen, 

 and oxygen, is built up in the form of granules in the 

 chlorophyll corpuscle, and the surplus oxygen escapes 

 into the sap and finds its way to the intercellular 

 passages, and thence through the stomata into the 

 atmosphere. 



It will be obvious from the foregoing that the 

 granules of starch represent so much matter (especially 

 carbon) obtained from the atmosphere outside the plant, 

 and so much energy obtained from the sun; each 

 granule may therefore be regarded as a packet of stored 

 energy and matter won from the external universe. 



The limits of this little book will not allow of my 

 going into details concerning the use which the plant 



