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 
eranules 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 
