I9I4.] CRILE— THE KINETIC SYSTEM. 281 



Graves' disease there is, therefore, a state of intensified conscious- 

 ness, which is associated with low brain thresholds to all stimuli — 

 both to stimuli that cause muscular action and to stimuli that cause 

 fever. The intensity of the kinetic discharge is seen in the constant 

 fine tremor. It is evident that the thresholds of the brain have been 

 sensitized. In this hypersensitization we find the following strong 

 evidence as to the identity of the various mechanisms for the pro- 

 duction of fever. In the state of superlative sensitization which is 

 seen in Graves' disease, we find that the stimuli that produce mus- 

 cular movement, the stimuli that produce emotional phenomena and 

 the stimuli that produce fever are as nearly as can be ascertained 

 equally effective. Clinical evidence regarding this point is abundant, 

 for in patients with Graves' disease we find that the three types of 

 conversion of energy resulting from emotional stimulation, from 

 nociceptor stimulation (pain), and from infection stimulation are, 

 as nearly as can be judged, equally exaggerated. In the acute cases 

 of Graves' disease the explosive conversion of latent energy into heat 

 and motion is unexcelled by any other known normal or pathological 

 phenomenon. Excessive thyroid secretion, as in thyrotoxicosis from 

 functioning adenomata, and excessive thyroid feeding, cause all the 

 phenomena of Graves' disease except the exophthalmos and the emo- 

 tional facies. Ligation of arteries, division of nerve supply and 

 excision of part of the gland may reverse the foregoing picture and 

 restore the normal condition. The patient notes the eft'ect on the 

 second day and often within a week is relatively quiescent. On the 

 contrary if there is thyroid deficiency there is the opposite state, 

 a reptilian sluggishness. 



At will, then, through diminished, normal or excessive adminis- 

 tration of thyroid secretion, we may produce an adynamic, a normal, 

 or an excessively dynamic state. By the thyroid influence, the brain 

 thresholds are lowered and life becomes exquisite; without its in- 

 fluence the brain becomes a globe of relatively inert substance. Ex- 

 cessive doses of iodin alone cause most of the symptoms of Graves' 

 disease. The active constituent of the thyroid is iodin in a special 

 protein combination. Thus is stored in the colloidal spaces. Hence 

 one would not expect to find changes in the cells of the thyroid gland 

 as a result of increased activity unless it be prolonged. 



