40 S. SAGUCHI 



Since the substances imported from the blood usually do not 

 appear as formed elements, it is safe to conclude that the various 

 cytoplasmic constituents of the islet cell are morphological ex- 

 pressions of substances formed by the elaboration of the imported 

 material and are to pass into the blood-stream. 



Now the question arises, which of the cytoplasmic constitu- 

 ents must be regarded as the specific secretion of the islet cell? 

 As for the specific granules, they are contained in the a and h 

 cells which are situated in the peripheral part of the typical islet 

 and which are often of such a form and an arrangement to sug- 

 gest compression against the neighboring acinus tissue, so that 

 they do not always come into intimate relationship with the 

 blood-capillary. These facts demonstrate sufficiently that the 

 specific granules take no important part in the secretion of the 

 islet cell. Like the mitochondrial substance to which they are 

 similar in chemical and staining reactions, they are to be regarded 

 rather as the mother-substance of secretion. 



The e cells, on the contrary, form the principal elements of the 

 islet, being in close relation to the blood-vesselsi The lipoid 

 corpuscles and urano-argentophile apparatus, which are present 

 in a fully developed state in the e cells, must therefore be looked 

 upon as specific, secreted matter of the islet. In a previous paper 

 ('20) I have shown that the acinus cell produces two sorts of 

 secretions: one derived from zymogen granules and the other 

 collected in the form of the Golgi intracellular apparatus. In a 

 similar manner, the islet cell produces the lipoid and urano-ar- 

 gentophile substance; the lipoid corpuscles differ in some respects 

 from zymogen granules, although the two are in accord in that 

 they both offer little resistance to the action of acetic acid; they 

 bear rather a strong resemblance in its chemical character to the 

 lipoid granules found in the basal portion of the acinus cell; at 

 least, the result of fixing and staining of the two is nearly the 

 same. The urano-argentophile apparatus, on the other hand, 

 corresponds to the Golgi intracellular apparatus of the acinus 

 cell in that they can both be brought into view by the Cajal 

 uranic nitrate-silver method. But that there is some difference 

 between them is obvious from the fact that the Weigl and Kopsch 



