THE SUGAR PRUNE 151 



And in point of fact, this is about the way in 

 which the chemist regards the matter. 



Starch is a compound of water and carbon. 

 The plant secures the water from the soil and the 

 carbon from the atmosphere, where it exists in 

 the form of carbonic acid gas, which is given 

 out constantly from the lungs of every living 

 animal. 



With these simple and universally present ma- 

 terials, then, the wonderful chemist of the plant 

 laboratory builds up the intricate substance 

 through glucose and levulose into what we term 

 starch. 



This substance is stored away in the plant 

 cells, not for the moment available for the pur- 

 pose of nutrition, but constituting a reserve store 

 of food material upon which the tissues of the 

 plant can draw at need. 



Starch itself when stored is insoluble in the 

 juice of the plant, but to make it available when- 

 ever needed it is only necessary for the plant 

 chemist to add to the compound the constituents 

 of a molecule of water, namely two atoms of 

 hydrogen and one of oxygen, and the starch is 

 transformed into a soluble sugar called glucose 

 or levulose. 



This substance, again dissolved in the juice of 

 the plant, may then be transferred to the place 



