THE THYROID APPARATUS 103 



slight. At a first glance, it might appear that the cardiac and 

 respiratory disturbances were referable to this cause. But more 

 careful investigation shows that the respiratory disturbance 

 results, partly from stenosis of the trachea due to pressure, and 

 partly from mechanical injury of the nerves of the larynx. The 

 cardiac derangement consists, anatomically and clinically, in 

 hypertrophy and dilatation, more particularly of the right heart. 

 It is brought about, partly by mechanical injury of the venous 

 circulation (Rose's goitre heart), and partly by the difficulty of 

 respiration (Kocher's goitre heart with dyspnoea) ; compression of 

 the nerves of the heart may also be a contributing factor. 



The cardio-vascular symptoms are the only ones which can 

 be regarded as of hyperthyrotoxic origin. These are : palpitation, 

 some tachycardia, slight cardiac enlargement, glittering of the 

 eyes, slight tremor, liability to perspire, and dermographism 

 (Kraus's goitre heart).* 



There is undoubtedly an analogy between the symptoms of 

 Graves's disease and those which are experimentally produced in 

 animals by hyperthyroidization. Moebius describes a pathological 

 sequence, commencing with simple goitre, the evidences of Graves's 

 disease afterwards developing one by one, until the complete 

 clinical picture of that condition is reproduced. Kraus, however, 

 does not consider that there are sufficient clinical grounds to 

 justify such a sequence. For, in the great majority of cases, 

 the characteristic signs of Graves's disease are absent in simple 

 goitre, and this applies very particularly to the typical metabolic 

 changes, a fact of primary importance. 



The functional aspect of simple goitre is not identical with 

 that of hyperthyroidism, and the hyperfunction suggested by 

 the anatomical conditions is most undoubtedly absent from the 

 clinical signs. But it must be remembered that the goitrous 

 degeneration of the thyroid gland represents the anatomical 

 diagnosis only ; that hypersecretion is not always demonstrable, 

 even histologically ; and that, though some portions of the gland 

 are hyperplastically changed and are more actively secretory, 

 others again are degenerated in such a way that their function 

 is reduced or even abolished. That "goitre" and "goitre," as 

 Kocher points out, "are not always identical," is proved by the 

 fact that, after thyroidectomy, symptoms of suppression may be 

 in some instances provoked, in others abolished, by the 

 development of a goitre from a portion of the gland left in situ. 

 That the anatomical hypertrophy of the thyroid may be 

 associated either with slight symptoms of hyperfunction or 



* E. Bircher (March, 1910) has recently shown that in rats with 

 parenchymatous goitres produced by means of goitre water, there is in- 

 variably an enlargement of the heart, shown by the increased weight and 

 the thickened walls. Bircher believes that the noxa of goitre has a direct 

 influence upon the heart. 



