IO2 INTERNAL SECRETION 



sexual organs, signs of hyper- and hypo-function occurring some- 

 times side by side. There is a possibility that the continued 

 increased activity gives rise to a temporary functional insufficiency, 

 which may, later, find anatomical expression. 



It is possible to account for all the symptoms of Grav.es's 

 disease by the continuous circulation in the blood of thyroid sub- 

 stances in abnormally large quantities. For it must be borne in 

 mind that, not only do the extent and intensity of the symptoms 

 depend upon the degree of thyroid affection, but they also depend 

 upon the modifying effect which the thyroid secretion itself exer- 

 cises upon the different organic tissues and functions. As Eppinger 

 and Hess with justice point out, the symptoms of derangement 

 will vary according to whether the subject is sympathetico-tonic 

 or vago-tonic. 



Graves's disease is the direct outcome of the flooding of the 

 organism with thyroid substances. These exercise an elective 

 stimulating effect upon the sympathetic, and partly also upon the 

 autonomous, portions of the vegetative nervous system ; and they 

 also influence the activity of those other internal secretory organs 

 which have functional interrelationships with the thyroid gl-and 

 (thymus, hypophysis, suprarenals, sexual glands). The question 

 now arises as to whether the primum movens of Graves's disease 

 is to be sought within the thyroid or without it. The etiology of 

 the condition is still shrouded in darkness. The remarkable 

 incidence of the disease in women, and the frequency with which 

 its occurrence is associated with functional changes of the sexual 

 glands, are undoubtedly factors of significance. Moreover, the 

 comparative frequency \vith which Graves's disease occurs in 

 persons with status thymicolymphaticus is probably something 

 more than coincidental. A more complete knowledge of the 

 innervation of the thyroid gland suggests the possibility that the 

 cause of the anomalous secretion is to be sought in a primary 

 affection of the sympathetic nerve, or of the nervous areas in which 

 it takes its rise. Thus we arrive at a neurogeno-thyrogenic theory 

 of the origin of Graves's disease. 



Another pathological condition which is associated with 

 clinical hyperthyrosis, is simple goitre. Goitre is a latent swelling 

 of the thyroid gland, unaccompanied by inflammation. 

 Anatomically, the degenerative process consists in hypertrophy 

 and hyperplasia of the gland, by which different parts of the 

 tissue may be affected in a varying degree. The functional dis- 

 turbances arising from a derangement of the internal secretion 

 are, however, comparatively unimportant. The profound meta- 

 bolic changes produced by the hyperfunction of Graves's disease 

 are absent in simple goitre, and up to now, an appreciable de- 

 parture from normal metabolism has not been observed. More- 

 over, the etiological connection between the pathological signs of 

 the disease and a change in the function of the thyroid, is very 



