Studies on the Endocrine Glands 279 



Thyroid Feedincr witli Intermission, and also with an 



Increased Dose. 



In these experiments dry ox-thyroid was added to the usual rusk paste. 

 Nine full-grown male rats were used, and were divided into three groups, 

 A, B, and C. The experiments were begun on July 19. 



A group. Control. — Two animals l^elonging to this group, viz. rats 

 Nos. 10 and 18, were killed on August 30; the third (rat No. 17) was 

 kept alive. One animal of the group suffered from slight diarrhcta for a 

 few days. 



B group (rats Nos. 19, 20, 21). Thyroid fed, with Intermittence. 

 — These animals were fed on the rusk diet alone until Auo-ust 1. From 

 August 2 to 8 they were put on thyroid diet. From August 9 to 15 this 

 was stopped, and they returned to the simple rusk diet. From August 

 16 to 22 they again received 1 grm. of dry ox-thyroid per rat per diem. 

 From August 28 to 29 they had the rusk diet alone. Most of the animals 

 suffered from diarrho-a during the first thyroid feeding. Their appetite 

 decreased considerably. They took a consideraljle amount of water. They 

 were inactive, and lost in weight : there was more falling out of hair than 

 before. During the second thyroid feeding the condition of the animals 

 was better, their appetite being less affected. Nos. 19 and 21 were 

 killed on August 30, and No. 20 on September 1(3; i.e. twenty-five days 

 after the second thyroid feeding had ceased. 



C group (rats Nos. 22, 23, 24). Thyroid fed, with Increasing 

 Dose. — The rats of this group were fed on ordinary rusk paste from July 19 

 to August 1. From August 2 to 8 they received 1 grm. of dry ox -thyroid 

 per rat per diem. From August 9 to 15 the amount was increased to 1*2 

 grm. From August 16 to 22 the amount given was 13 grm. From August 

 23 to 29 they received 1'5 grm. per rat per diem. 



During the first week of thyroid feeding there was decrease of appetite, 

 inactivity, and diarrhftta. During the second the same symptoms were 

 seen, and the falling out of the hair was much more marked. During the 

 third and fourth periods the general condition of the animals improved. 



Effect on Structure of Pancreas. — All these animals were killed 

 on August 30. Nos. 16 and 18 showed no appreciable departure from 

 normal. In Nos. 19, 20, and 21 the pancreas appeared somewhat enlarged 

 as compared with the controls. The colour was light pink, paler in 20 than 

 in 19 and 21. 



In Nos. 22, 23, 24 the pancreas was of a pink colour, and appeared 

 somewhat enlarged. In No. 24 the intestines were a little congested. 



Pancreas. — Examination of the pancreas of the rats employed in 

 Series 4 (thyroid feeding with intermission and with increasing dose) 

 gave tlie following results: — In Nos. 19, 20, 21 (Group B) the alveoli 

 generally are large, although quite small in some parts. Many of 

 the alveolar cells are large, but they have small ones amongst them; 



