PANCREATIC JUICE. 37! 



that the secretion of the pancreas is entirely suspended during the intervals of digestion. 

 This fact has been definitely settled by Bernard and can easily be observed by opening 

 animals in digestion and while fasting. In the first instance, the pancreatic duct will be 

 found full of normal secretion, and, in the other, it will be almost, if not entirely, empty. 

 Bernard has also found that the pancreatic juice begins to flow into the duodenum during 

 the first periods of stomach-digestion, before alimentary matters have begun to pass in 

 quantity into the intestine. 



FIG. 76. Pancreatic jixtula. (Bernard.) 



Full-grown shepherd-do? (female), in which a pancreatic fistula has been established A, silver tube to which a 

 bladder has been attached; B, bladder; C, stopcock for the purpose of collecting the juice which accumulates 

 in the bladder. 



Another important fact determined by Bernard is that the secretion of the pancreas 

 is readily modified by irritation and inflammation following the operation. When we 

 come to treat of the general properties of the normal pancreatic fluid, it will be seen that 

 its characteristics are, decided alkalinity, viscid consistence, and coagulability by heat. 

 It is almost always the case that, a few hours after the canula is fixed in the duct, the 

 juice loses some of these characters and flows in abnormal quantity. With respect to 

 susceptibility to irritation, the pancreas is peculiar ; and its secretion is sometimes ab- 

 normal from the first moments of the experiment, especially if the operative procedure 

 have been prolonged and difficult. That the properties above described are characteristic 

 of the normal pancreatic secretion, there can be no doubt ; as, in all instances, fluid taken 

 from the pancreatic duct of an animal suddenly killed while in full digestion is strongly 

 alkaline, viscid, and coagnlable by heat. This excessive sensitiveness of the pancreas has 

 rendered fruitless all the attempts of Bernard to establish a permanent pancreatic fistula 

 from which the normal juice could be collected ; and we are not disposed to admit that 

 the fluid collected by recent German observers, from permanent fistulas, represents phys- 

 iological conditions. 



General Properties and Composition of the Pancreatic Juice. In all the inferior ani- 

 mals from which the pancreatic secretion has been obtained in a normal condition, the 

 fluid has been found to present pretty uniform characters. It is viscid, slightly opaline, 



