26 S. SAGUCHI 



membrane, thus assuming a polj^gonal or stellate form. The 

 fact worthy of note is that the solitary islet cells are in close rela- 

 tion to the blood-capillaries, just as the case with the typical 

 islet. In fact, the blood-capillary with which they are in contact 

 is in a distended condition. 



Besides the solitary islet cells, there are found scattered through 

 the pancreas small groups of cells. These behave, in relation to 

 the neighboring acinus cells as well as to the basal membrane, 

 like the solitary cells. These groups of cells may be designated 

 as non-tj'pical islets. The cells composing them belong either 

 to one or to several acini (figs. 3, b, e; 7). In the latter instance 

 the islet cells belonging to different acini are usually separated 

 by a blood-capillary to which they converge. In either case, 

 the islet in question is composed, in most cases, of two kinds of 

 cells — b and e. It is extremely rare to see an islet composed of 

 e cells only. The b cells are situated at the periphery of this 

 group, while the e cells are in the center; in other words, the e 

 cells are separated from the neighboring acinus cells by b cells. 

 Islets of this type are distributed throughout the pancreas; in the 

 superficial portion of the organ, however, they are rarely met 

 with. 



The most characteristic feature of the solitary islet cells and 

 of the cells composing the non-typical islet above referred to is 

 that they are situated in the acinus and are arranged in the same 

 row as the neighboring acinus cells (fig. 7) . In the third form of 

 cell groups, which may be designated as typical islets, the cells 

 are disposed in an entirely different manner. Figures 1, 4, 5, 

 and 6 show parts of such a typical islet. It consists of cell cords 

 which anastomose with one another and form a sort of network, 

 the meshes of which are occupied by blood-capillaries. The ends 

 of the cord may pass gradually into the pancreatic acini or may 

 be separated from the latter by the basal membrane. In the 

 former case islet cells are in immediate contact with acinus cells; 

 in other words, the islet cells are enclosed by a connective-tissue 

 membrane which is in direct continuity with the basal membrane 

 of the acini. The cells composing the cord are mostly of elon- 

 gated cylindrical form, and are arranged in a row in side-by-side 



