298 E. R. HOSKINS 



were 25 per cent heavier than those of 18 controls. The same 

 author ('10 b) fed thyroid to pregnant guinea pigs. Many 

 abortions and several still-born occurred. The newborn (ap- 

 parently normal) young of the treated mothers weighed on the 

 average 12 grams less than the controls. The hypophysis 

 showed an average decrease in weight of 10 per cent, the supra- 

 renals 26 per cent and 2 per cent for the females and males 

 respectively; the ovaries 26 per cent; and the thyroid gland 18 

 per cent. The thymus was increased 58 per cent. 



Carlson, Rooks and McKie ('12) and Ferrant ('13) fed thy- 

 roid to birds and mammals, including man. They concluded 

 that large doses of thyroid are toxic. In the thyroid fed rabbits 

 of Ferrant the heart, liver and pancreas showed degenerative 

 changes. 



Schafer ('12) fed thyroid to young white rats, noting an in- 

 creased food consumption, increased metabolism and accelera- 

 tion of growth, 



Gudernatsch ('12, '14) found that thyroid administered to a 

 large number of tadpoles retarded growth (i.e., a toxic effect) 

 but hastened metamorphosis of the limbs and tail. It is prob- 

 able that this acceleration is due to an increase in the rate of the 

 circulation and general metabolism. Lenhart ('15) reaches the 

 same conclusion. The present writer, in a similar (unpublished) 

 experiment (with larval frogs and Ambystomae) fed large 

 doses and noted only the toxic effect. Coutronei ('14), West 

 ('14), Morse ('15) Abderhalden ('15) and Romeis ('15) have 

 recently confirmed in general the results of Gudernatsch. 



Hewitt ('14) fed thyroid gland to white rats, noting a loss in 

 weight. 



Livingston ('14) found that feeding thyroid inhibits the hyper- 

 trophy of the hypophysis which follows thyroidectomy in male 

 rabbits. 



Gudernatsch ('15) fed thyroid to albino rats. This treatment 

 retarded growth and interfered with pregnancy. The effect 

 produced is probably due merely to the toxicity of thyroid, as 

 Stockard ('13) obtained quite similar results in animals treated 

 with alcohol. 



