OTHER USEFUL PLANTS 83 



atoms of hydrogen only, whereas cane sugar has 

 thirty-two; and six atoms of oxygen, in contrast 

 with the sixteen atoms of the cane sugar 

 molecule. 



We have elsewhere seen that starch is a com- 

 pound of the same elements; differing, indeed, 

 from glucose only in that it has ten hydrogen 

 atoms instead of twelve, and five oxygen atoms 

 instead of six. 



Stated in chemical terms, a molecule of starch 

 that has had a molecule of water incor- 

 porated with its substance in a chemical union, 

 becomes a molecule of glucose; and, of course, 

 the converse holds a dehydrated molecule of 

 glucose becomes a molecule of starch. 



But to build up a molecule of cane sugar from 

 either starch or glucose requires the introduction 

 and incorporation of many individual atoms, 

 although no new kinds of atoms are required. 

 It is simply that the molecule of cane sugar is 

 a very much more intricate structure, made of 

 the same material. The glucose molecule is, if 

 you will, a simple dwelling; the cane sugar 

 molecule an elaborate mansion. 



But the materials with which they are com- 

 pounded are precisely the same. 



There is a good deal of uncertainty on the 

 part of the chemists as to the exact way in which 



