314 Kojima 



the amount of zymogen. No appreciable difference can be seen in 

 the islets. 



Summary. — In the bird the mitoses in the pancreas, which in the 

 rat are produced by thyroid feeding, have not been detected, but there is 

 the same tendency to diminution in the amount of zymogen in the 

 alveolar cells. 



General Summary. 



Effects of Thyroid Feeding upon the General System. 



The effects upon the general system which in my experiments have 

 resulted from thyroid administration are — 



(a) diminution of appetite and loss of weight ; 



(b) increased shedding of hairs ; 



(c) disturbances of the digestive system ; 



(d) diminution in both nitrogenous and gaseous metabolism. (This is 



dealt with later in a separate paper) ; 



(e) with prolonged feeding there may be a subsequent increase of 



weight, the appetite being regained. 



I have usually found that the appetite begins to diminish after three 

 or four days' administration, so that the animals take far less food (see 

 Tables VI. and VII.) and the body-weight gradually decreases. Diarrhoea 

 is sometimes present. Most of the animals become inactive. In rats the 

 fur becomes rough, and the hairs fall out much more than normally. 

 Throughout this period post-mortem examination shows congestion of 

 the intestines, with soft or watery contents. In some cases the congestion 

 is confined to the duodenum. 



When the thyroid feeding is continued for more than a week the 

 symptoms gradually disappear. They are more marked with feeding 

 than with subcutaneous injection of thyroid decoction. Possibly this is 

 due to a smaller proportion of the effective autacoid being present in the 

 decoction than in the whole thyroid. 



The above symptoms caused by thyroid administration have been noted 

 by many previous observers. 



Presence of Iodine in the Urine. 



It is well known that iodine is almost always present in the thyroid, 

 although there is marked variation in its amount in different individuals 

 and in different species of animals. These variations probably depend on 

 diet, but there are also seasonal and geographical variations — Martin (9), 

 Guyer (10), Hutchison (11), Martindale (12), and others. I find that 

 whereas the urine of the normal rat always orives a neo-ative reaction when 

 tested for iodine, the iodine test becomes positive after thyroid feeding and 

 also after subcutaneous injection of thyroid decoction. In the latter case 

 it appears about seven hours after the injection. If the thyroid feeding 



