THE THYROID APPARATUS 9 1 



cutaneous injection of large quantities of iodothyrin, but the result 

 was by no means invariable. In many cases, in spite of flooding 

 with iodothyrin, there was neither tachycardia nor any other sym- 

 ptom of thyroid poisoning. They believe that the production of 

 tachycardia is not specific to the thyroid gland, but that it is 

 common to iodothyrin and to certain other iodized derivatives of 

 albumin. In the case of thyroid extract, they explain the effect 

 by the large amount of iodized albumin which the thyroid gland 

 contains. 



Coronedi regards thyroid extract as a physiological diuretic. 

 He bases his view upon results obtained with thyroparathyroidec- 

 tomized animals having a reduced activity of the kidneys. A very 

 marked diuresis was produced with thyroid extract in cases where 

 the usual diuretics had failed. 



The effects of thyroid extract upon metabolism are constant. 

 It has already been shown that the exhibition of thyroid substances 

 in myxcedema and other conditions arising from suppression of 

 the thyroid gland, is followed by an enormously increased meta- 

 bolism. Similar changes, though less marked in character, are 

 produced in normal subjects, both man and animals, although the 

 physiological turnover (Grundumsatz) is very little affected by 

 thyroid extract. If, however, thyroid extract or iodothyrin are 

 given continuously for two to three weeks, the amount of the CO 2 

 excretion will be increased by 15 to 25 per cent. The nitrogenous 

 interchanges, however, are invariably disturbed by the exhibition 

 of thyroid extract. The increased decomposition of albumin is 

 expressed by an increased excretion of nitrogen, hence the nitrogen 

 balance is a negative one. By increasing the caloric food supply 

 the nitrogen losses may be avoided. In obesity, owing to the 

 large reserve, the loss of albumin is not as great as in the normal 

 subject. 



Thyroid preparations have been largely employed in the 

 therapeutics of obesity and, in many instances, with success. 

 Magnus-Levy thinks that the increase in oxidation during the 

 resting state (Ruhegaswechsel) is not sufficient to account for the 

 reduction of adipose tissue which follows the exhibition of thyroid. 

 He believes that the result is largely due to an increased expendi- 

 ture; for the effect of thyroid extract is to increase the capacity 

 for nervous reaction and, as a consequence, these otherwise 

 phlegmatic people display a greater energy in movement. There 

 is a good deal of evidence to show that thyroid extract has an 

 effect in reducing constitutional obesity, but that it has very little 

 influence upon obesity due to overfeeding; and this seems to point 

 unmistakably to the conclusion that, in this case also, we have 

 to do with a " substitution," by means of thyroid extract, of the 

 diminished function of the normal thyroid gland. 



With regard to the metabolism of salts, Falta, with Bolaffio 

 and Tedesco, showed that the administration of thyroidin produced 



