PLATE 3 



EXPLANATION OF FIGURES 



Figures 9, 10, 14, 15, 17, 20, and 21 are of sections of the pancreas fixed and 

 stained as in figure 1, plate 1. Figures 8, 11, 12, and 16 are of preparations 

 treated as in figure 2, plate 1. Figure 13 is of a section fixed in Zenker's fluid and 

 stained with iron-hematoxylin. Figure 18: fixing according to Meves and stain- 

 ing with iron-hematoxylin. Figure 19: the same fixing and staining as figure 7. 

 Figure 22: fixing according to Rabl (sublimate-picric acid) and staining with 

 iron-hematoxylin. Figure 23: fixing in trichloracetic acid according to Holm- 

 gren and staining with Mayer's hemalum. X2400. 



In figures 8 to 59, all cells are so delineated that the cell-ends where they 

 are in contact with blood-capillaries are always directed toward the lower side 

 of the plate, except the case in which the islet cell comes in contact with the 

 blood-vessel at both ends. X2400. 



8 to 11 Various stages of transformation of acinus cells into islet cells. In 

 figures 8 and 9 the nucleus and the cytoplasm show the nucleolar hyperchromasy; 

 mitochondrial filaments being in the process of liquefaction. Figures 10 and 11 

 show the passing out of an intranuclear constituent in the form of filaments or of 

 granules; diminution of the nucleolus. X2400. 



12 and 13 Accumulation of the granules and filaments passed out. X2400. 



14 a-type of cell. X2400. 



15 A transitional form between the a-type and b- or e-types of cell. X2400. 



16 /^-type of cell, containing specific granules and some lipoid corpuscles. 

 X2400. 



17 6-type of cell. X2400. 



18 e-type of cell, containing delicate mitochondrial filaments, and vacuoles 

 corresponding to the lipoid corpuscles dissolved out. X2400. 



19 e-type of cell, containing mitochondrial filaments, which are somewhat 

 thickened in consequence of the action of osmic acid. X2400. 



20 d-type of cell. X2400. 



21 e-type of cell. X2400. 



22 e-type of cell, containing pigment corpuscles and granules. X2400. 



23 e-type of cell; the nuclear network is distinctly stained with hemahmi. 

 X2400. 



5:) 



