GLANDULAR CELLS OF THE FROG'S PANCREAS 355 



may be rendered evident when we compare with each other the 

 preparations which are fixed in the same manner, but tinged in 

 different ways, e.g., the iron-haematoxylin stain with the Benda's, 

 as applied to the material fixed after Meves (figs. 26 and 27), 

 or the haemalum stain with the Benda's as applied to the mate- 

 rial fixed in sublimate-acetic mixture (figs. 10, 11 and 13). From 

 these observations I have gained the impression that the nucleo- 

 lar corpuscles are imbedded in the chromatin granules or cords. 

 This 'mpression was deepened by the appearance of the clear 

 vacuoles or canalicules in the middle of the gray- or blue-stained 

 chromatin granules or cords, in the preparations fixed in trichlor- 

 acetic acid and stained with iron- or alum-haematoxylin (figs. 

 29, 30). I concluded that this was, at least in part, a negative 

 appearance due to the nucleolar corpuscles being dissolved out 

 or remaining unstained. 



As regards the genesis of the nucleolar corpuscles, I am fully 

 convinced that they are derived from the main- or side-nucleoli. 

 As before stated, the main-nucleolus is surrounded by a deeply 

 staining cortex, the outer surface of which is not only uneven, but 

 frequently furnished with granules or rods of various shapes and 

 sizes but of the same staining reaction as the cortical substance 

 (figs. 17 to 20, 26, 55). These granules or rods often appear to 

 be separating from the cortex. From these facts and from the fact 

 that the cortex with its appendages exhibits the same staining 

 reaction as the nucleolar corpuscles, the inference is warranted that 

 the two are the same thing, and that the latter are formed by bud- 

 ding and separating from the former. Now the question arises, 

 is the picture above mentioned not to be regarded as representing 

 a fusion of the nucleolar corpuscles with the nucleolus in order 

 to cause the increase in volume of the latter? I, however, insist 

 on the view above advocated by me ; for I hold that the nucleolar 

 corpuscles are correlated with the vital activities going on in the 

 cytoplasm, as will be described later on, and that their separation 

 from the nucleolus and their progress toward the periphery are 

 conditions which must be fulfilled in making the above assump- 

 tion. It is quite conceivable, even rational, that the nucleolar 

 corpuscles, in passing toward the periphery, would make their 



