THE MOUTH SWALLOWING; SALIVARY DIGESTION 69 



grains, and permits a reaction between the enzyme and 

 the separated molecules of the carbohydrate. 



The change from starch to sugar seems not to be effected" 

 by a single reaction, but by stages. Physiologic chemists 

 have studied extensively the numerous intermediate bodies 

 which have a fugitive existence in the process. Most of I 

 these are covered by the term dextrins. It is sufficient for< 

 our present purpose to regard them as carbohydrates, 

 simpler in their molecular structure than the original stare] 

 but complex as compared with the familiar sugars. We 

 have said that the chief product oLsalivar^y^rolysisJs 

 malt-sugar^ or maltose. This is one of several sugars 

 classed asjiisaccharixls. It can be hydrolyzed further to 

 form dextrose (or glucose), a sugar of the simplest type, 

 and one which is ready to be absorbed and to minister 

 to the living tissues. Some dextrose is said to be formed 

 in prolonged salivary digestion, but the cleavage lags 

 when the maltose stage has been reached. 



