186 CHEMICAL MECHANISMS OF SECRETION 



intestine taken at different levels showed a decreasing amount 

 of activity as the intestine was descended, corresponding to the 

 known effects upon the pancreatic secretion of injection of acid 



FIG. 5. Action of Acid Extract of boiled and washed Mucous Membrane 

 of Duodenum. A, Blood Pressure ; B, Drops of Pancreatic Juice ; C, Drops of 

 Bile. (Bayliss and Starling.) 



FIG. 6. Action of Acid Extract of Mucous Membrane of Duodenum 

 which had been dried after Dehydration by Alcohol. A, Blood Pressure ; 

 B, Drops of Pancreatic Juice. (Bayliss and Starling. } 



into these various portions. Thus injection of acid into a loop 

 from the lower end of the ileum gives rise to no pancreatic secretion, 

 and corresponding to this, an acid extract from the mucous 



