grinders. While they do this in concert with the 

 cheeks, they squeeze a thin Jiquor from the adjacent 

 glands. This moistens the food and prepares it for 

 digestion. When the month is inactive these are 

 nearly closed : but when we speak or eat, their 

 moisture bemg then necessary, is expressed as needs re- 

 quire. 



But the food could not descend merely by its own 

 weight, through a narrow and clammy passage into 

 the stomach. Therefore to effect this, muscles both 

 strait and circular are provided. The former enlarge 

 the cavity, and give an easy admittance. The latter, 

 closing behind the descending aliment, press it down- 

 ward. But before the food enters the gullet, it must 

 of necessity pass over the orifice of the wind-pipe :< 

 whence it is in danger of falling upon the lungs, which 

 might occasion instant death. To obviate this, a 

 m veable lid is placed, which when the smallest par- 

 ticle advances, is pulled down and shut close, but as 

 soon as it is swallowed, is let loose and stands open. 

 Thus the important pass is always made sure against 

 any noxious approaches ; yet always left free for 'the 

 air, and open for respiration. 



The food descending into the stomach, is not yet 

 ready for the bowels. Therefore that great receiver 

 is strong to bear, and proper to detain it, till t is 

 wrought iiito the smoothest pulp imaginable. From 

 hence it is discharged by a gentle force, and passes 

 gradually into uie intestines. 



Near the entrance waits the gall-bladder, ready to 

 pour its salutary juice upon the aliment, which dis. 

 solves any thing vicid, scours the intestines, and keeps 

 all the fine apertures clear. This bag, a-> the sto- 

 mach fills, is pressed thereby,and then only discharges 

 its contents. It is also furnished with a valve of a 

 very peculiar nature, namely of a spiral form ; through 

 which the detersive liquid cannot hastily pour, but 

 must gently ooze. Admirable construction ! which 

 without any care of ours, gives the needful supply, and 

 ,110 more. 



