THE SEEDLING AND YOUNG PLANT. 87 



vades the universe penetrate into the system. By 

 means of the energy thus derived from the sun, the 

 molecules of carbon dioxide and water are broken up in 

 the meshes of this chlorophyll corpuscle, and experi- 

 ments 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 pres- 

 ent position of science enables us to say that, be these 

 what they may, the chlorophyll corpuscle gains energy 

 from the sun, and brings this energy to bear on the car- 

 bon dioxide and water in such a way that it does work 

 in tearing asunder their molecules in the substance of 

 the corpuscle. Then a curious series of results follow. 

 The carbon, oxygen, and hydrogen undergo new re-ar- 

 rangements, 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 pas- 

 sages, and thence through the stomata into the atmos- 

 phere. 



It will be obvious from the foregoing that the gran- 

 ules of starch represent so much matter (especially car- 

 bon) obtained from the atmosphere outside the plant, 

 and so much energy obtained from the sun ; each gran- 

 ule 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 



