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R. R. BENSLEY 



concerning the interpretation of which I am in doubt. Possibly 

 they represent in part a secretion antecedent. 



TRANSITIONS BETWEEN ACINUS CELLS AND ISLET CELLS 



Having now defined the islet cell as an element containing gran- 

 ules which are peculiar to each type of cell composing the islet, 

 and which occur in no other cell of the pancreas, it is possible to 

 discuss on this basis the question of what should be accepted as a 

 scientific demonstration of cells which are intermediate in type 

 between islet cells and acinus cells. 



Fig. 14 Section of an acinus of the pancreas of the guinea pig, showing centro- 

 acinous cells with mitochondria and fuchsinophile bodies. In the acinus cells 

 may be seen, zymogen granules, and long mitochondrial filaments. Acetic osmic 

 bichromate, anilin acid fuchsin, methyl green. X 1555. 



It has been shown that the acinus cells have two constituents 

 which are not present in the islet cell, namely zymogen granules 

 and basophile substance, and also that each type of islet cell con- 

 tains granules which are peculiar to itself and which are not pres- 

 ent in the cells of the acini. Tt has also been shown that the duct 

 cell contains neither the specific constituents of the acinus cell 

 nor those of either islet cell. The mitochondria, moreover, while 

 present in all four types have characters of their own for each type. 



