PLATE 4 



EXPLAXATIOX OF FIGURES 



Figures 24 to 33 are treated according to the Cajal's uranic nitrate-silver 

 method for the Golgi's network. Figures 34 to 41: according t ) Weigl's osmic 

 acid method for the Golgi's net. Figures 42 to 44: fixing in saturated solution 

 of sublimate, and staining with iron-hematoxylin. X2400. 



24 Acinus cell preparing for transformation into the islet cell, the product of 

 liquefaction of mitochondria being seen as droplets stained a darkly brown 

 color. X2400. 



25 to 28 Various stages of develojiment of the urano-argentophile apparatus. 

 The cells belong to the a- and ?;-typ'3s. X2400. 



29 and 30 Cells (e-type) containing the fully developed urano-argentophile 

 apparatus, and vacuoles corresponding to the lipoid corpuscles dissolved out. 

 X2400. 



31 and 32 Cells belonging to the c-type. X2400. 



33 A cell with the darkly staining protoplasm and the filamentous urano- 

 argentophile apparatus, perhaps corresponding to the d-type. X2400. 



34 to 37 Acinus cells preparing to transform into islet cells, round or oval 

 irregularly shaped corpuscles appearing in the cytoplasm. X2400. 



38 to 40, 42 to 44 Various forms of the Golgi's network. X2400. 



41 A fully developed e-cell, which contains no Golgi apparatus. X2400. 



52 



