. XXV. 2. 3. STOMACH A*D INTESTINES, 3.21 



in the fame manner as we often fwallow our fpit.tle 

 without attending to it. 



The ruminating cbfs of animals have the power 

 to invert the motion of their gullet, and of their 

 fir (I ftomach, from the flimulus of this aliment, 

 when it is a little further prepared ; as is their daily 

 practice in chewing the cud ; and appears to the eye 

 of any one, who attends to them, whilft they are 

 employed in the fecond maftication of their food. 



2. When our natural aliment arrives into the 

 ftomach, this organ is ftimulated into its proper 

 vermicular aftion ; which beginning at the upper 

 orifice of it, and terminating at the lower one, 

 gradually mixes together and pumes forwards the 

 digefting materials into the inteltine beneath it. 



At the fame time the glands, that fupply the 

 gaftric juices, which ,are neceffary to promote the 

 chemical part of the procefs of digeftion, are ftimu- 

 lated to difcharge their contained fluids, and to 

 feparate a further fupply from the blood-veflels : and 

 the lacleals or lymphatics, which open their mouths 

 into the ftomach, are ftimulated into a&ion, and 

 take up fome part of the digefting materials. 



3. The remainder of thefe digefting materials is 

 carried forvvards into the upper inteftines, and 

 ftimulates them into their periftaltic motion fimilar 

 to that of- the ftomach ; wljich continues gradually 

 to mix the changing materials, and pafs them along 

 through the valve of the colon to the excretory end 

 &f this great gland, the fphincter ani. 



The digefting materials produce a flow of bile, 

 and of pancreatic juice, as they pafs along the duo- 

 denum, by ftimulating the excretory duels of the 

 liver and pancreas, which terminate in that inte- 

 ftine : and other branches of the abforbent or lym- 

 phatic fyftem, called lacleals, are excited to drink 

 up, as it pailes, thofe parts of the digefting mate- 

 rials. 



