CYTOLOGICAL STUDIES OF LANGERHANS'S ISLETS 21 



panies no degenerative process of the islet cell. So far as I have 

 been able to ascertain, the islet cell undergoes no degeneration, at 

 least there are visible no changes in the nucleus which maj^ be 

 looked upon as degenerative. In a word, the islet cells multiply 

 either by mitosis or amitosis, without decreasing in number by 

 degeneration. 



THE RELATIONS BETWEEN THE DIFFERENT TYPES OF ISLET CELLS 



x4.s shown in the preceding pages, the islet cell contains several 

 cytoplasmic structures, w^hich are not found in an equally devel- 

 oped state in one and the same cell, but rather in such a way that 

 a given group of cells will be rich in one structure, while another 

 group is poor in it. This makes possible several modes of clas- 

 sification of islet cells according to the character and amount of 

 the structures concerned. These classifications have already 

 been referred to. The next important step is to determine the 

 types of islet cells by summarizing the results thus obtained. 

 As I pointed out in the introduction, there is always danger of 

 misinterpretation if one tries to classify the islet cells according 

 to one or two in distinct* properties. We must therefore take into 

 account as many positive structural characteristics as possible. 

 The most practical and convenient plan is to sort out the cells 

 according to a given structure, which serves as the fundament of 

 classification, and then assign other structures to the types thus 

 determined. 



The following descriptions of the nuclei are based upon the 

 preparations stained with iron hematoxylin or acid fuchsin, as 

 the alum-hematoxylin preparation does not reveal any marked 

 differences between the nuclei in the different types of cells. 



1. a cells. This type of cell (fig. 14) is heavily laden with spe- 

 cific granules which are deeply stained with iron-hematoxylin or 

 acid fuchsin. While mitochondria are lacking in these cells, it 

 is highly probable that they are represented by the specific gran- 

 ules, the two structures bearing a striking resemblance to each 

 other in their microchemical reactions. On the other hand, a 

 cells contain few or no lipoid corpuscles, while the urano-argento- 



