290 Kojima 



alcohol and ether, has, when administered with the food, an effect similar 

 to that produced by whole thyroid. 



Effect of Subcutaneous Injection of Thyroid Decoction. 



The effects of subcutaneous injection of a decoction made from dry ox- 

 thyroid by boiling with distilled water was investigated in a male rat 

 (No. 55), weight 150 grm., the equivalent of 1 grm. of dry ox-thyroid being 

 administered per diem for five days. The animal showed no special 

 symptoms with regard to appetite, etc. At the end of the period the 

 weio-ht was 130 grm. From seven hours after the first injection onwards 

 the test for iodine in the urine was positive. 



Post-mortem there is very little to record. The stomach contained only 

 a small amount of food, and the intestines appeared slightly congested. 



Pancreas. — The weig^ht was 0'6 grm. The alveoli are both larg^e 

 and small, and this applies also to their cells. The nuclei vary from 

 S'7fj. to 9/x, a considerable number being large and many deeply 

 stained by hsematoxylin ; there are abundant coarse chromatin 

 granules. Mitotic figures are seen in some of the cells. There is 

 but little diminution of zymogen. No change is observable in the 

 islets. 



Summary. — Subcutaneous injection of thyroid decoction produces 

 similar changes in the pancreas to those produced by thyroid feeding, but 

 less marked. Probably the active substance is only in part taken up by 

 the water used for extraction. This is, indeed, shown by the fact that in 

 the feeding experiments the residue after extraction by water produces 

 all the usual effects. 



Does Castratiox affect the Results of Prolonged 



Thyroid Feeding? 



The effect of thyroid feeding upon the pancreas of castrated male rats 

 was next investigated. But it Avas first necessary to determine whether 

 changes are produced in the pancreas by castration alone. 



Four full-grown male rats were castrated on May 16, and all were kept 

 in one metabolism cage, four other entire male rats of similar size beincy 

 kept in another cage as a control. All eight were fed on the standard food 

 of rusks and water. During the first week after the operation the appetite 

 of the castrated animals was somewhat less than that of the others, but it 

 gradually improved ; after a few days they took considerably" more food than 

 the controls, and their weights increased to a remarkable extent (Table 

 XIIL). This increase appears to have been largel}^ due to an addition to the 

 adipose tissue, especially that under the skin and in the mesenteric folds. 



