86 



CRILE— PHYLOGENETIC ASSOCIATION 



[April 22, 



there must be secreted in excessive amount some substance that 

 activates the motor mechanism ; then too the nervous system in 

 Graves' Disease is hypersusceptible to stimuli and to thyroid extract. 

 It might follow that even a normal amount of thyroid secretion 



Fig. 5. This photograph of fear closely resembles the expression of patients 

 afflicted with Graves' disease or exophthalmic goiter. 



would lead to excessive stimulation of the hypersusceptible motor 

 mechanism. 



This condition of excessive motor activity and hyperexcitability 

 may endure for years. What is the source of this pathologic ex- 

 citation ? 



The following facts may give a clue, viz., in suitable cases of 

 Graves' Disease if the thyroid secretion is sufficiently diminished by 

 a removal of a part of the gland or by interruption of the nerve and 

 the blood supply, the phenomena of the disease are immediately 

 diminished, and in favorable cases the patient is restored to approx- 

 imately the normal condition. The heart slows, the respiration 

 falls, the restlessness diminishes, digestive disturbances disappear, 



