STUDIES ON THE PANCREAS OF THE GUINEA PIG 301 



The differences of opinion that exist with respect to the relation 

 of islets to ducts are not at first sight easy to understand, for it 

 would seem to be an easy matter to demonstrate connections 

 with ducts if such exist. Nevertheless Laguesse maintains that 

 the islets are, in general, in direct continuity with ducts, though 

 the majority of observers are agreed that this is not the case. The 

 apparent reason of this is that few investigators have patiently 

 worked through complete series of sections as Laguesse has, and 

 there was no method for demonstrating the connections when the 

 methods of injection and impregnation failed. There can be, 

 however, no doubt as to Laguesse 's results, for his figures show 

 clearly the connections which he describes. The only question 

 is how often the connections with ducts occur. This question 

 can only be answered if we have at our disposal a method which 

 takes the place of the injection method and brings all the ducts 

 of the pancreas to view including those described by Laguesse 

 as going to islets of Langerhans. 



The purpose of the investigation, the results of which are 

 recorded in the following pages, has been to find methods for the 

 accurate diagnosis of the several epithehal tissues of the pancreas 

 from one another, and to apply these methods to the questions 

 raised by experimental studies of the pancreas as to the relations 

 existing between the islets of Langerhans on the one hand and the 

 acini and ducts on the other. A second object was to apply meth- 

 ods of accurate enumeration to the islets of Langerhans under 

 different experimental conditions. A third object was the deter- 

 mination of the true anatomical relation of the islets of Langerhans 

 to the ducts of the pancreas. 



The work is a continuation of that begun in this laboratory by 

 M. A. Lane, who, following the demonstrations of the specific 

 granules of the islet cell by Tschassonikow ('00), and Laguesse 

 ('99), and that of the presence of two sorts of cells in the islet by 

 Schulze ('00), and Diamare ('99), estabhshed criteria for dis- 

 tinguishing the granules of the two sorts of cells from one another 

 and from the zymogen granules of the acinus cells. As far as 

 the pancreas of the guinea pig is concerned the technical needs 

 have been fully met by new methods, and some of these methods 

 may be applied, to what extent will be indicated in a suitable place, 

 to the study of the pancreas of other animals. 



