Studies on the Endocrine Glands 307 



for five days (August 10-15). From the third day onwards the appetite of 

 the animals decreased. At the end of the feeding they weighed 18 grm. 

 and 20 grm. respectively. Two control mice on the same diet but without 

 thyroid showed no appreciable alteration in weight. 



Post-mortem the intestines in both animals appear to be slightly con- 

 gested. The stomach is full of food. 



Pancreas. — The alveolar cells are, if aiij-thing, larger than in the 

 normal pancreas of the mouse. Many of the nuclei are enlarged, 

 measuring from 7'OfjL to 10/x. All are deeply stained by hajmatoxylin, 

 and contain coarse chromatin granules and large nucleoli staining red 

 with Mallory. A certain number of the cells show mitoses. No 

 vacuolation can be .seen. There is a general diminution of zymogen 

 granules, including the alveoli which are situated immediately round 

 the islets. The islets are compact in structure, and are composed of 

 cells which are nearly equal in size and appearance and contain 

 uniformly sized nuclei. Tlieir nucleoli are large, and stain red with 

 Mallory. Their cytoplasm has fine granules which stain red by 

 Mallory. The thyroid feeding does not appear to produce any 

 change in the islets. 



Summary. — Thyroid feeding produces changes in the pancreas of the 

 mouse similar to those w^hich have been described in the rat. 



Effects of Thyroid Feeding and Thyroid Injection on 



Cats and Dogs. 



In the first instance, two full-grown male and two full-grown female 

 cats were fed with an addition of sheep's thyroid or dry ox-thyroid to 

 their ordinary diet of bread and milk and fish or other meat food. The 

 two female cats, Nos. 15 (pregnant) and 16 (non-pregnant), weighed respec- 

 tively 2775 grm. and 2750 grm. They received 20 grm. of fresh thyroid 

 per cat per diem, : the appetite of both animals decreased. On the third 

 day of the feeding the pregnant cat gave birth to four kittens (apparently 

 full time), which died shortly after birth. At the end of ten days' feeding 

 the cats weighed respectively 2690 grm. and 2700 grm. The two male 

 cats were— Xo. 17, weight 3100 grm., and No. 18, weight 2750 grm. The 

 former received 20 grm. of fresh sheep's thyroid per diem for five days, 

 the latter 17 grm. of dry ox-thyroid per diem for five days. In both the 

 appetite was diminished after four days' feeding. The weight of cat 

 No. 17 was 3070 grm. when killed, that of No. 18, 2750 grm. (the same as 

 at the commencement). A third male cat was injected subcutaneously each 

 day during five days with a decoction of thyroid substance made from 

 30 grm. of dry ox-thyroid. No special symptoms regarding appetite were 

 observed in this animal. The weight at the commencement of the experi- 

 ment was 3050 grm., at the end 2950 grm. The urine in this animal gave 

 an intensive reaction when tested for iodine. 



Pancreas, — The alveolar cells are mostly of the same size as 

 those of the normal cat's pancreas. They are smaller than those 



