CHEMISTRY OF A LUMP OF SUGAR, 93 



acid ; this is glucose. Another, which is known as 

 levulose, or fruit sugar, is found, mixed with glu- 

 cose, in honey and in manna, which is an exuda- 

 tion from a species of ash, Fraxinus ornus, com- 

 mon in southern Europe. Our meadow and upland 

 grasses contain a sweet substance, which is prob- 

 ably cane sugar ; and it is to this that much of the 

 value of these plants as food for cattle may fairly be 

 attributed. In the laboratory of the plant, cane 

 sugar can be changed over into fruit or grape sugar, 

 and back again, with apparently the greatest facil- 

 ity ; but this we cannot do in our working labora- 

 tories. We can change cane to grape sugar ; but we 

 cannot move a step in the other direction. The 

 chemist or discoverer who invents a way of chang- 

 ing grape sugar or starch sugar readily into sucrose 

 or cane sugar will confer great benefit upon the 

 arts, and immortality upon himself. It is doubtful 

 if this will ever be accomplished. In all the chemi- 

 ical transformations involved in changing one sugar 

 into another, no other elements but those of simple 

 water are assimilated or used. 



The sugar-cane furnishes immense quantities of 

 sucrose ; in fact, it stands first among the sources 

 of supply, and beets come next. It is singular that a 

 rank, reedy cane and a soft, pulpy root should sup- 

 ply sugar identical in composition, and in the larg- 

 est quantities. Cane sugar is the sweetest of all 



