Studies on the Endocrine Glands 



309 



mitosis could be obtained, nor was there any vacuolation of the 

 cells. The zvniotjen irranules are, however, diminished in amount as 

 compared with the normal (fi^s. 24, 25). This is the case even with 

 the alveoli imuu-tliately surrDundinf,^ the islets, which in tlie cat, as 

 in the rat, siiow more abundant zymogen than the rest of the 

 pancreas. There is no appreciable difference to be seen in the islets 

 as compared with those of the normal pancreas. 



Two experiments were made upon the dog. (1) A young male fox 

 terrier (weight 4H.50 grm.) was fed with meat, porridge and milk, to 

 which was added during ten days 13 grm. of fresh sheep's thyroid per 

 diem. This addition to the food produced no appreciable symptoms. 

 At the end of the ten days the weight of the animal was 4950 grm. 



Fig. 26. — Section ofjiancreas of dog (male}, normal. Microphotograph ; magnified 

 400 diameters. Mallory's stain. 



The zymogen granules are very abundant in the cells, and are stained dark 

 red by the acid fuchsin, coming out black in the photograph. 



(2) The second dog taken, a non-pregnant female, was also a fox terrier 

 (weight 6500 grm.). This animal, which was purely meat-fed (lights), 

 received 39 grm. of dry ox-thyroid per diem during six days, in addition 

 to its ordinary food. Again no appreciable symptoms were observable, 

 and there was no perceptible change in weight. 



Pancreas. — Many of the alveolar cells appear small. Their 

 nuclei are fairly large, and although the majority measure from 

 5/u. to 6/A, a considerable number are as large as 7'5/x to 9ft.. There is 

 no evidence of mitosis, nor is there any vacuolation of the cells. 

 Zymogen granules are more scanty than in the normal dog's pancreas 

 (figs. 26 and 27). The islets show no change. 



In the dog also it is to be noted that z\'mogen granules are 

 specially abundant in the alveoli immediately surrounding the islets, 

 even in the normal animal. This difference is more apparent in 



