EFFECTS OF FOOD ON PANCREATIC SECRETION. 127 



local effect in any case is not confined to these substances is apparent 

 from the fact that the inhibitory influence is not confined to them, but 

 belongs also to other bodies readily soluble in water (Dr. Damaskin). 

 Oae gathers the impression that certain substances which are easily 

 soluble in water diminish its ordinary properties and prevent it from 

 acting as a local stimulant. 



Such are the facts which this laboratory .has collected concerning the 

 normal excitants of the pancreatic gland. We believe we are justified 

 in characterising them as new, although the idea of a special stimulat- 

 ing effect caused by acids and by the acid chyme was long ago expressed. 

 However, it is a long way from the mere expression of an opinion to 

 a clear and precise statement of facts. And that the idea obtained no 

 general recognition, because it was not founded on any definite basis, is 

 shown by this, that in recent articles and text-books only a stimulating 

 effect of the food as a whole is mentioned. 



I have now, gentlemen, completed the part of these lectures which 

 deals with gastric and pancreatic secretions, but I am far from believing 

 that the subject is thereby in reality exhausted. Much, very much, 

 has still to be achieved before we are able to congratulate ourselves on 

 a final conquest of our territory. That which is gained is already very 

 valuable, because it may serve as a sign-post to guide future research. 

 We have now many more open questions before us than we had a 

 short time ago, and all these questions mean progress in our investiga- 

 tions, because they testify to the existence of a wide field of inquiry 

 which we have studied from a general point of view, but which we now 

 wish to submit to exhaustive research. The questions are so many that 

 we must group them together for discussion. 



In the second lecture we learned of the great complexity, but at the 

 same time great constancy and accuracy, of the work of the gastric 

 glands and of the pancreas. It is now necessary to seek an explanation 

 for every step of this complicated process, and in doing bo the require- 

 ments of the individual food constituents, and the conditions necessary 

 for the welfare of the digestive canal, and for the organism as u whole, 

 must be borne in mind. In particular we must answer the following 

 questions : Why at any given moment a certain quantity of juice and 

 not any other is secreted ? Why has it certain properties and not any 

 other ? In what way do its quantitative and qualitative variations 

 advance the digestion of the food ? How are they of service to the 

 healthy condition of the digestive canal and of the organism as a 

 whole? To these questions others are linked, such as, how do nil these 

 variations of gland activity come about ? 



We have previously spoken of the foods and subdivided them into 

 their separate component materials, but we have not by a long way 



