USES OF SALIVA. IO7 



impossible to swallow, if it were not moistened. This 

 fact was made use of in the former East Indian rice- 

 ordeal. All suspected persons were brought together 

 and given parched rice to eat. The guilty individual, 

 believing that his gods would bring his crime to light, 

 usually had his salivary glands paralyzed by fear, and 

 so could not secrete enough saliva to enable him to 

 swallow the dry rice ; while those with clear con- 

 sciences had no difficulty. (3) Saliva, by dissolving 

 many solid substances, enables us to taste them. 

 Things in the solid state cannot be tasted, as you may 

 easily discover by wiping your tongue dry and placing 

 a piece of lump-sugar on it. Until a little moisture has 

 come out and dissolved some of the sugar, no taste will 

 be perceived. (4) Saliva turns starch, which is not itself 

 nourishing, into sugar, which is. 



17. Digestion in the Mouth. By means of the teeth, the 

 solid parts of our food are cut and crushed. At the 

 same time, they are softened and made ready for swal- 

 lowing by mixture with the saliva. Saliva also alters 

 some nourishing substances in the food, and so changes 

 them that instead of being insoluble they become readily 

 soluble. 



18. The Action of Saliva upon Starch. Raw starch 

 may be mixed with water, but will not dissolve in it. 

 After a while, all the starch settles down from such a 

 mixture. When starch is boiled in water, it swells up 

 very much and mixes more thoroughly with the water 

 than raw starch does, but still it does not dissolve. If 



17. How is digestion carried on in the mouth? What are the uses 

 of saliva ? 



18. What happens when starch is mixed with water? When 

 boiled ? What happens if you strain a solution of sugar and water ? 



