274 Kojima 



(c) In Thyroidectomised Rat. 



No. 3 rat of group C. Parathyroid-fed (after thyroid). Weight 

 235 grm. Thyroidectomised forty-eight days before death. Post-mortem 

 slififht congrestion is noticeable in the small intestine. 



Pancreas. — The alveoli are distinctly larger than in the rats 

 killed immediately after thyroid feeding. Their cells are of nearly 

 equal size; they contain abundance of zymogen granules. The 

 nuclei vary in size from S'lfx to 6"2/x. Many have coarse chromatin 

 granules ; some an enlarged nucleolus which stains red with Mallory. 

 There is nowhere evidence of mitosis, and no apparent change in the 

 islets. 



Summary of the Effects of Thyroid and Parathyroid Feeding 



upon the Rat's Pancreas. 



(1) After a week upon thyroid diet the pancreas of the rat shows 

 typical changes, viz. (a) the alveoli are smaller than normal ; (b) most 

 of the alveolar cells are smaller than normal ; (c) the nuclei vary in size, 

 many being enlarged and deeply stained ; (d) the cytoplasm of the alveolar 

 cells exhibits in places a marked and characteristic vacuolation ; (e) many 

 of the alveolar cells show typical mitotic figures indicative of rapid multi- 

 plication; and (f) they contain comparatively little zymogen. 



(2) After intermission of thyroid feeding the pancreas shows a decreas- 

 ing number of mitotic figures, whilst the amount of zymogen and the 

 ofeneral size of the cells again becomes increased, although the variations 

 in size of the alveolar cells and of the nuclei are still manifest; the 

 alveoli themselves continue for some time to be smaller than normal. 



(3) Addition of a small amount of ox-parathyroid to the daily diet is 

 not productive of any marked changes in the pancreas. 



(4) In none of the experiments have any alterations been observed in 

 the islets of Langerhans. 



Thyroid Feeding in Different Sexes. 



This series of experiments was primarily intended for the investigation 

 of the effects, if any, upon general and gaseous metabolism of feeding with 

 thyroid and with parathyroid in the two sexes,^ but the animals were sub- 

 sequently used for histological observation, and the results of the post-mortem 

 findings may therefore be given here. The parathyroid used was obtained 

 from the ox, and was dried and powdered. The thyroid was sheep's thyroid 

 obtained fresh from the slaughter-house. 



Three full-grown male and three non-pregnant female rats were used, 

 and were divided into two groups. From April 28 to May 11 all were 

 fed on ground rusks and water alone. From May 12 to May 18 there 

 was added to this diet 0*1 grm. of dry ox-parathyroid per rat per diem. 



1 The observations relating to metabolism are given in a eubsequent paper (p. 351 

 of this vohime). 



