STUDIES ON THE PANCREAS OF THE GUINEA PIG 341 



quency of this connection in the adult pancreas, though they 

 record experimental observations which indicate that the duct 

 epithelium possesses the power of forming islets even in adult 

 life. 



On the other hand there are many authors who not only deny 

 any connection of the islets with the ducts but even maintain that 

 those located in the lobules of the pancreas are wholly independent 

 of the surrounding acinus tissue, being separated from it by a com- 

 plete fibrous capsule. 



The facts brought forward by Laguesse on the one hand, and 

 by Weichselbaum and Kyrle on the other, relative to their obser- 

 vations of the occurrence of direct connections between the duct 

 and islets, admit of no discussion, for the illustrations furnished 

 by the authors are too clear and convincing to be evaded. The 

 only question that may be discussed is the frequency of these 

 occurrences. At first sight, taking into consideration the nega- 

 tive results of the injection and impregnation methods, it would 

 seem probable that the cases observed by Laguesse and by Weich- 

 selbaum and Kyrle were simply instances where the islet had 

 failed to complete its development and to separate from the 

 mother tissue. But, when one considers the difficulty of demon- 

 strating such connections with ducts, at least by the study of 

 serial sections, the suspicion seems justified that many more 

 connections escape notice in a series than are observed. 



Laguesse ('06-'08) himself discusses the possibility of the con- 

 nections breaking temporarily or even definitively in islets about 

 to disappear, but after his latest studies is not willing to admit 

 this, even, he says, though he remain alone in maintaining that 

 there is a connection. 



Laguesse and his pupils, as a matter of fact, do stand alone in 

 claiming that the islets are usually connected with ducts or with 

 acini, though others, who believe that, in general, they are sep- 

 arate, admit the occasional occurrence of such connections. 

 Pearce ('03) describes the separation of islet and acini as occurring 

 at about the third month in the human embryo, but finds solid 

 cords of cells connecting them in a case of syphilitic pancreatitis 

 of the new born. Continuity of acini and islets are described by 



