Effect of Tljyroid-Feodinjj on tho Supnirrnals 



51 



experiment. Tlii.s animal died suddenly on the 24th day of the ex- 

 periment ; its suprarenals wore examined some hours later. It appeared 

 the strongest animal of the series. All were apparently ht-althy. and 

 only ditiVT»'<l in appearance froni the normal animals in the greater 

 roughness of their coats. The thyroid-fed animals eonsumetl much more 

 food than the control rats, hut were somewhat thinner. 



Wkicht of the Sri>U.\UENAL.S. 



In the normal animals of the first series the weight of the suprarenals 

 varies from 21 to 41 mg., the average for the thirteen rats being 2!) mg. 

 According to Donaldson's statistics the weight of the suprarenals of the 

 male rat after 40 to 50 days of age increases fairl}' uniforndy with the 

 aire and weicrht of the animal. Thus the average weight of the supra- 

 renals of a rat with a body-weight of 107 grm. is 22 mg., which is the 

 figure found in the first rat of the normal series. For a rat of 290 grm. 

 weight the suprarenal average weight is 44 mg. It will be seen that the 

 figures recorded in Table I. agree very closely with the averages given by 

 Donaldson. 



In the second series of normal rats the weight of the suprarenals is 

 very constant at about 25 mg., a figure rather less than Donaldson's, 

 which is 27 mg. for a rat with a body- weight of 143 grm. 



The effect on the weight of the suprarenals of feeding with small doses 

 of thyroid is very distinct In the first series of animals (Table II.) the 



