PANCREATIC JUICE AND ITS ACTION UPON FOOD. 179 



a part of it ; in the intestine the two secretions may act together, to 

 complete the liquefaction of the alimentary materials. 



Mode of Secretion and Daily Quantity of the Pancreatic Juice. 

 If examined in the living animal by means of a canula introduced into 

 its excretory duct, it is found that the action of the pancreas is by no 

 means the same at different times. If there be no food in the stomach or 

 intestine, or if the process of digestion be arrested from any cause, no 

 fluid whatever is discharged from the canula. If digestion be going on, 

 the pancreatic juice soon begins to run from the orifice of the tube, at 

 first slowly and in successive drops. Sometimes the drops follow each 

 other with rapidity for a few moments, and then an interval occurs 

 during which the secretion seems entirely suspended. After a time it 

 recommences, and continues to exhibit similar fluctuations during the 

 whole course of the experiment. Its flow, however, is at all times 

 scanty, as compared with that of the gastric juice. We have never 

 been able to collect, in a good sized dog, more than 75 grammes in the 

 course of three hours, and usually the quantity was much less than this. 

 Colin found a great variation in the animals upon which he experimented, 

 the quantity being from two and a half to thirty times as abundant at 

 one period as at another. In the bullock, the largest quantity obtained 

 was 342 grammes per hour while the animal was engaged in rumination. 



The entire quantity of pancreatic juice secreted per day cannot be 

 determined with precision, but it is evidently moderate in amount, as 

 compared with the other digestive fluids. In the ox, cow, and horse, 

 Colin found the average quantity nearly the same, corresponding to 

 about 0.58 gramme per hour for every kilogramme of the animal's 

 weight. Schmidt, in his experiments upon the dog, found it, in recently 

 established fistulae, not more than 0.2 gramme per kilogramme per hour. 

 In the most successful instances, we have found it in the dog, as much 

 as 1.25 grammes per kilogramme per hour during active digestion, but 

 much less than this in the intervals. If we take, as the average of these 

 estimates, 0.5 gramme per hour for every kilogramme of bodily weight, 

 it would give for a man of medium size about 800 grammes as the entire 

 quantity of pancreatic juice secreted per day. 



The condition of the pancreas varies at different periods corresponding 

 with the activity of its secretion. In the intervals of digestion it is 

 comparatively pallid and dense ; during digestion it becomes turgid and 

 vascular, its ruddy color showing the increased quantity of blood circu- 

 lating in its vessels. According to most observers, the substance which 

 is efficient in the solution of albuminous matters can only be extracted 

 from the pancreas at this time, during the height of its vascularity and 

 digestive action, which, in the dog, is from five to seven hours after the 

 ingestion of food. When the process of digestion is terminated, its 

 vascularity again diminishes, and the organ returns to its quiescent 

 condition. This periodical excitement during the period of functional 

 activity, though well marked in the pancreas, is not peculiar to it, but 

 may also be seen in the mucous membrane of the stomach and the small 



