14 THE THYROID AND 



way in which it absorbs the subcutaneous thickening of 

 myxcedema and cretinism. It is not surprising, there- 

 fore, that it should be able to deal also with gummata 

 and atheroma. By its absorptive effect on the athe- 

 roma, it may work some improvement in aneurysm. 



EXOPHTHALMIC GOITRE. 



The arguments in favour of the hypersecretion 

 theory of this disease appear to almost all observers 

 to be of overwhelming strength. The thyroid 

 gland is enlarged, vascular, and soft in most cases ; 

 occasionally it is normal in size. Microscopically, 

 the acini are dilated and irregular, and the contents 

 too watery. These are just the changes seen in the 

 actively secreting fragment left after a sub-total 

 thyroidectomy. The colloid contains too much 

 iodothyrin as compared with the normal gland. 

 The wasting, restlessness, and quick pulse may all 

 be reproduced with constancy in man or animals 

 by thyroid feeding, and exophthalmos has also been 

 obtained occasionally in both man and the monkey. 

 The bearing of these conclusions on treatment will 

 now be considered. 



PRACTICAL DEDUCTIONS. 



We may seek here to summarize the conclusions, 

 in so far as they are of importance to the clinician, 

 that the New Physiology has reached. We learn 

 that parenchymatous goitre is a hypertrophy of the 

 thyroid gland, designed to enable it to obtain 

 sufficient iodine from the blood, this element being 

 an essential constituent of its internal secretion. 

 The deficiency in iodine is in some complicated way 



