THE THYROID AND PARATHYROID GLANDS 799 



to those of the disease known as exophthalmic goiter. Indeed, the symp- 

 toms are so much alike in the two conditions that it is scarcely neces- 

 sary to describe them specially for the disease except to mention that 

 in the former exophthalmos generally does not occur. 



Like simple goiter this variety is from three to four times more fre- 

 quent in women than in men, a fact of significance when we recall the 

 evidence of association between the thyroid gland and the generative 

 organs. It is said that the disease is usually coupled with persistence of 

 the thymus gland. The thyroid gland in exophthalmic goiter is enlarged, 

 sometimes in one lobe; it is hard and pulpy, and on auscultation a mur- 

 mur is heard. Histologically the gland presents a picture very like 

 that which lias been described above as hyperplasia ; that is to say, the 

 vesicles have a deficiency of colloid material; their epithelium is colum- 

 nar and folded up into the vesicles; and the interstitial tissue between 

 the vesicles is very markedly increased. 



Exophthalmic goiter is generally claimed to be due to hyper- 

 secretion of the thyroid, because: (1) the symptoms of the disease are not 

 unlike those produced by excessive administration of thyroid to a normal 

 individual; and (2) they are in general opposite in character to the symp- 

 toms found in cases where the thyroid gland is atrophied. The blood of 

 a person with exophthalmic goiter when injected into mice increases their 

 resistance to the toxic action of acetonitrile, which is also the case after 

 thyroid extract has been injected. In many cases of exophthalmic goiter 

 partial removal of the gland is said to ameliorate the symptoms. Other 

 clinicians, however, state that if the patient is given proper medical 

 treatment, rest, and diet, equally beneficial results can be obtained. 



Certain investigators, however, deny that it has yet been conclusively 

 demonstrated that exophthalmic goiter is due to hypersecretion of the thy- 

 roid (Marine). 43 It is pointed out that, if hypersecretion were the cause of 

 the disease, one would expect that the injection into animals of the blood 

 of patients suffering from it would produce symptoms similar to those 

 following the injection of thyroid extract. The results of such experi- 

 ments, however, have been extremely confusing and very indecisive, since 

 it is difficult to recognize in laboratory animals many of the characteristic 

 symptoms, especially those affecting the skin and eyes and the general 

 bodily nutrition. Another difficulty in accepting the hypersecretion hypoth- 

 esis is the fact that an extract of a gland removed from an exophthalmic 

 patient has no different physiological action on a normal animal from an 

 extract of a normal gland containing the same percentage of iodine. 

 The evidence is by no means conclusive one way or the other, and it may 

 well be that the observed changes in the thyroid gland are not the cause 

 of the symptoms of exophthalmic goiter, but merely, like the other symp- 



