Studies on the Endocrint' (JIjukIs 



2G9 



more abundant in tlie alveoli innnediately adjacent to the islets of 

 Lan<,aMhans than in more remote alveoli. 



Tilt.' islets themselves show nn fhan'^o from the normal. 



(c) In Thyroidectomised Animal. 



Xo. 2 rat of C tjroup. Thyroid-fed. Wei<,dit ITOtjrm. Killed forty- 

 one days after thyroidectomy. 



The intestines are slit,ditly congested.- The contents of the large 

 intestine are soft. The pancreas is of a pinkish colour. 





YUi. 10.— Section of pancreas of rat (male) which had been subjected to thyroidectomy 

 and subsequently fed with an addition to its ordinary diet of 1 grm. of dry ox- 

 thyroid per diem during seven days. Microphotograph ; magnified 90 diameters. 



Great variation is noticeable in tlie size of the alveoli, largely due to ditierences 

 in the amount of zymogen within the cells. 



Pancreas (figs. 10, 11). — The alveolar cells show a good deal of 

 difference in appearance (fig. 10). Their nuclei vary in size from 4/x 

 to lOjUL. The smaller nuclei are placed closely together; the cells to 

 which these small nuclei belong are smaller than the rest. The larger 

 nuclei contain coarsely granular uniformly scattered chromatin, but 

 some have a large central nucleolus with a tendency for the chromatin 

 granules to be arranged near the periphery of the nucleus. A greater 

 number of mitotic figures (fig. 11) are observable than in the sections 

 of pancreas of the animal belonging to B group ; perhaps as many as 

 in the unoperated animal, but this is a point not easy to determine. 

 Some of the cells show characteristic vacuolation. Zymogen granules 

 are in general scanty, although, as usual, in greater number in the 

 immediate neighbourhood of the islets. The latter show, as before, 

 no special departure from the normal. 



