CHAPTEE YI. 



INSALIVATION. 



General considerations Parotid saliva Relations of the parotid secretion to 

 mastication Submaxillary saliva Relations of the submaxillary secretion 

 to mastication and gustation Sublingual saliva Fluids from the smaller 

 glands of the mouth, tongue, and fauces Mixed saliva Quantity of saliva 

 General properties and composition of the saliva Functions of the saliva Ac- 

 tion of the saliva on starch Mechanical functions of the saliva. 



ONE of the most important of the digestive processes 

 which take place in the mouth is the incorporation of the 

 saliva with the food, or insalivation. Not only has this fluid 

 a mechanical function, assisting to reduce the food to the 

 proper form and consistence to be easily swallowed, but it 

 seems to be necessary to the proper performance of the sub- 

 sequent processes of digestion, and is concerned to a consid- 

 erable extent in the transformation of starch into sugar. That 

 the saliva is necessary to digestion is proven by the grave 

 effects upon the general function of nutrition which follow 

 its loss in any considerable quantity. This occasionally oc- 

 curs from the habit of excessive spitting, or as the result of 

 salivary fistula. It becomes important, therefore, to study 

 the physical and chemical properties of the saliva, the sources 

 from which it is derived, and its mechanical and chemical 

 functions in digestion. 



Saliva. 



The fluid which is mixed with the food in mastication, 

 which moistens the mucous membrane of the mouth, and 



