14 



PHYSIOLOGY AND HEALTH. 



next stage of the process of dige'st'on in the stomach. It 

 must be not only crushed and divided, but it must be mois- 

 tened and reduced to a pulpy consistence. For the purpose 

 of supplying the necessary moisture, there is provided in the 

 mouth a set of glands, which prepare and throw out the 

 saliva or spittle, sufficient, in time of health, to moisten and 

 soften all the food. These little glands are placed in the 



FIG. II. Salivary Glands. 



cheeks, (Fig. II. ,) and under the tongue, (Fig. II. &,) and 

 under the jaws, (Fig. II. c,) and open, through very minute 

 tubes and apertures, into the mouth, (Fig. II. d,d.) When the 

 cheeks and tongue are still, these glands are . inactive, and 

 throw-out no more liquid than enough to keep the mouth moist. 

 The presence of any matter in the mouth, the chewing of our 

 food, tobacco, &/c., and any motion of the jaws, cheeks, or 

 tongue, excite these glands, and induce the flow of their 

 fluids. All these motions are entirely needless, except when 

 we are eating or talking. They are under our control, and 

 consequently the flow of saliva is under our command. If, 

 then, we use the mouth only for its intended purposes of 

 eating arid conversation, it will be always moist, but never 

 full of saliva ; and then we should have no occasion to in- 

 dulge in the unnatural and offensive habit of spitting. 



