98 INTERNAL SECRETION 



increased vagal activity ; they also attribute (though somewhat 

 arbitrarily) the increased perspiration, the congestions and the 

 circumscribed oedema to irritation of the autonomous nerves. 

 These authors divide their cases of Graves's disease into two 

 groups ; one, in which the symptoms of sympathetic excitement 

 predominate, they describe as sympathetico-tonic ; while the other 

 is described as vago-tonic, from the fact that here the most 

 marked symptoms are those proceeding from the autonomous 

 nervous system. Falta, Eppinger and Riidinger assume a poly- 

 valency of the thyroid secretion and they regard the hyper- 

 thyroidism of Graves's disease as the outcome of a simultaneous, 

 though probably independent, stimulation of both the sympathetic 

 and autonomous nervous systems. 



A special interest attaches to the metabolic changes of 

 Graves's disease. In simple goitre, the metabolism is in no way 

 different to the normal, and it is affected by thyroid extract in a 

 manner precisely similar to that of other persons with normal 

 thyroids. In Graves's disease, on the other hand, the metabolic 

 changes are so characteristic of the condition that they constitute 

 important diagnostic criteria. The metabolism of Graves's disease 

 is characterized by an increased expenditure of energy. The 

 respiratory interchange of gases shows an increase of 50 per cent., 

 and even 70 to So per cent., in the amount of oxygen 

 consumed (Magnus-Levy, Salomon), and these results are 

 confirmed by Steyrer, who continued his experiments over 

 a long period of time. The increased consumption and the 

 increased and remarkably fluctuating caloric production, is 

 partly the result of the augmented cardiac and respiratory 

 activity; in part, and to an even greater degree, it is due 

 to the nervous excitement and motor unrest, more particularly 

 the tremor. But, after making due allowance for the operation 

 of these factors, it will be found that in complete muscular repose 

 there is still a large increase in the interchange of gases. When 

 we remember the effect of thyroid extract upon metabolism, it 

 seems obvious that this augmentation is only to be accounted 

 for by a hypersecretion of the thyroid gland. That the caloric 

 production may be still further increased by the exhibition of 

 thyroid extract, has not as yet been proved (Magnus-Levy, 

 Steyrer). It may be noted here that the administration both of 

 rhodagen and of Moebius's anti-thyroidin serum is not followed 

 by any demonstrable effect upon metabolism. This applies also 

 to treatment with thymus extract, at one time much vaunted for 

 its curative effect in Graves's disease. The enormously increased 

 metabolism accounts for the emaciation, which is often very 

 extreme. The increased caloric explains the subjective sensation 

 of heat, the profuse outbreaks of perspiration, and the tendency, 

 commented upon by Charcot, to a heightened temperature. That 

 the increased caloric does not produce hyperpyrexia or even fever 



