ANGIONEUROTIC EDEMA 277 



ous vasoconstricting apparatus a relationship simi- 

 lar in kind to that existing between the vasodilating 

 apparatus of the involuntary nervous system and the 

 thyroid, but a relationship devoted to a purpose dia- 

 metrically opposed namely, reenforced vasoconstric- 

 tion. 



Of the two functions, vasodilation and vasoconstric- 

 tion, the former is produced most easily. That it suc- 

 cumbs most readily under repeated or severe stimulus 

 unless supported by an adequate rise in thyroid con- 

 tent of the blood, would seem most likely from the 

 natural sequence of events occurring in abnormal as 

 well as normal subjects. Patients with a complete ab- 

 sence of the thyroid show no tendency to blushing or 

 peripheral vasodilation, but on the contrary, are in a 

 state of marked chronic peripheral vasoconstriction. 

 These patients possess an involuntary nervous mech- 

 anism inactivated by reason of the absence of the thy- 

 roid principle. Mild hypothyroidism shows but little 

 tendency to peripheral vasodilation under nervous 

 stimulation, a constant vasoconstriction of more or 

 less marked degree existing instead; whereas hyper- 

 thyroidism shows a constant vasodilation varying in 

 degree with the grade of hyperthyroidism. 



[I cannot refrain from remarking here that in 

 hypothyroidism, and especially in the more decided 

 types as myxedeme fruste, or myxedema, there is al- 

 ways a mechanical factor involved as a result of the 

 mechanical puffing of the cells, the so-called infiltra- 

 tion first emphasized by Hertoghe. To my mind, the 

 local circulatory findings mentioned by the essayist 

 are more mechanical in character than functional or 

 nervous the cells are dilated and (myx-)edematous 

 and, consequently, the intercellular capillary circula- 

 tion is almost impossible. H. R. H.] 



The thyroid gland being supplied by nerve filaments 

 from the involuntary system in common with all other 



