LECTURE IV. 173 



a large piece of meat has been swallowed 

 at once. Towards the great end, the food 

 will be found but little altered, towards the 

 middle more, and towards the pylorus it 

 will be similar to that which is found in the 

 duodenum. Mr. Hunter was apprized, that 

 the duodenum in some animals, might be 

 considered as serving to digest the food ; 

 for it is formed of considerable capacity, 

 resembling a stomach, and is chiefly recog- 

 nized by anatomists as that intestine, in 

 consequence of the biliary and pancreatic 

 ducts terminating in it. He also perceived, 

 that when the pylorus is not detentive, the 

 gastric fluids might flow into the duodenum, 

 and there complete the process of digestion. 



The solvent liquors are secreted from the 

 lining of the stomach, or sometimes poured 

 into it from glands situated at its upper 

 opening. The latter is commonly found 

 in birds, because the lining of their sto- 

 machs is formed for trituration, and conse- 

 quently not for secretion. Yet the same 

 kind of structure is met with in other ani- 

 mals, and even among quadrupeds in the 



