THE KINETIC SYSTEM 183 



were given subsequent to a division of the nerve supply to 

 the adrenals or subsequent to deep morphinization. 



The Relation of the Thyroid to Energy Transformation 



Although activity of the thyroid is not attended by 

 striking histologic changes, and while as yet there is no 

 available test by which to determine the presence of 

 thyroid secretion in the blood, there is other evidence 

 which proves that the thyroid plays an important role 

 in the process of energy transformation. It is known 

 that the specific activity of the thyroid is dependent on 

 the presence of iodin in combination with certain pro- 

 teins in the colloid material of the gland, from which it 

 is apparently mobilized by activating stimuli. As we 

 have already stated in the preceding chapter, Aschoff, 

 Beebe, and others have shown that electrical stimulation 

 of the nerve supply to the thyroid results in a marked 

 diminution in its iodin content. Marine, Beebe and 

 others have shown that the hyperactive thyroid gland in 

 Graves' disease is markedly deficient in iodin content. 



The meagerness of laboratory studies, however, is 

 amply compensated by the observations which the 

 surgeon has been able to make on a vast scale, ob- 

 servations which are as definite as are the results of 

 laboratory experiments. Unlike the brain cells and the 

 adrenals which are securely concealed from the eye of 

 the clinician, the thyroid is plainly visible ; and gross 

 changes in it are easily seen. A rich store of clinical 

 evidence exists, which confirms the postulate that both 

 the normal and the enlarged thyroid are stimulated 

 to increased activity by agents that cause functional 

 and histologic changes in the brain, the adrenals and 



