Studios oil the Kiidocriui.' Glanrls 



267 



which ftie hirj^er than normal, are deeply stained by it but without 

 sliowini; distinct ci>roniatin crranules. The zyniocren <;innules of the 

 alveolar cells ai'f in t^mcral scanty as conipared with those of the 

 aniniuls killed without thyroid teedin;; {t\^. !l; compare with firj. 4). 



Besides the ordinary and the dividin^^ cells, many small cells occur 

 packed closely toirether; they contain small, rather deeply stained 

 nuclei, which are often in pairs, and su^f<;est the idea that they are the 

 result of division. The small cells contain but few zymoLa'n c-rannles 

 and these are scattered in tiie cytoplasm of the inner zone. As in 

 the normal pancreas, the zymogen is more conspicuous in the alveoli 







#^^ 



>./-> 







Fio. 8. — Portion of a section from the same pancreas as that shown in fif.'. 7, but 

 magnified 500 diameters. Hematoxylin preparation. 



Notice tlie great variation in size of the alveolar cells, and also a consideiable 

 variation in tlie size of their nuclei as compared with the normal pancreas 

 (fig. 2). Tiie coarseness of the chromatin gi-anules within the nuclei is also to 

 be observed, and in some a very distinct, centrally situated nucleolus. Several 

 of the cells show mitoses. The amount of zymogen in the alveoli is variable, 

 but there is much less than in the normal pancreas. In this section the inner 

 zymogen-containing zone has remained completely unstained by the hematoxylin. 



which immediately surround the islets of Langerhans. In nearly all 

 parts some of the alveolar cells exhibit vacuoles, the vacuolation being 

 occasionall}' marked (fig. 12); it is, however, not uniformly dis- 

 tributed. Such vacuolisation is very characteristic of the pancreas 

 of the thyroid-fed animal. The vacuoles vary in size; some are large 

 enough to occupy a large portion of the cytoplasm, others are smaller. 

 They are always quite clear and sharply outlined, and are not to be 

 mistaken for the more faintly outlined vacuoles which are seen after 

 parathyroidectomy and sometimes in the pancreas of the normal 

 animal. The vacuolisation was most marked when fresh sheep- 

 thyroid had been used (p. 275). 



