THE THYROID 195 



One might think that the thyroid is over active in endemic goiter, 

 since it is enlarged. However, the reverse is true as the general 

 symptoms are the same as in myxedema. Thyroid tissue is rich in 

 iodine. This is a constituent always present in drinking water 

 of localities near the sea, in sea weed, and in sea foods 'such as 

 oysters and crabs. When people live in areas remote from the 

 sea, they drink glacial water which is practically lacking in iodine. 

 Endemic goiter is usually prevalent in such districts. An example 

 is our own Great Lake district. Studies have been made in many 

 schools in these localities. Inorganic iodides have been admin- 

 istered to the children and iodine has been put in their drinking 

 water. Within a short time the number of cases of goiter showed 

 a remarkable decrease. However, it is probably unwise to feed 

 iodine as a treatment to all people suffering from endemic goiter. 

 In case the gland is already enlarged, the iodine may stimulate 

 the gland to produce too much thyroxin. This would increase 

 the metabolism of the body. When people suffer from excessive 

 thyroid activity, foods containing iodine are often removed from 

 their diets. In all cases iodine should be used only upon the 

 advice of a physician. 



An excessive secretion of thyroxin gives rise to a disease called 

 exophthalmic goiter. The symptoms are just the opposite of those 

 in underactivity of the gland. Instead of a stupid, apathetic con- 

 dition there is a restless, nervous one. There is a wasting away of 

 tissues in spite of an enormous increase in food consumption. The 

 pulse and heart action are very rapid and often irregular. The 

 thyroid usually increases in size accompanied by an abnormal 

 protrusion of the eyeballs. There are various treatments, the most 

 successful being complete rest in order to slow up metabolism. 

 Sometimes, X-rays are used to check the activity of secretion and 

 sometimes the gland is partially removed. A more common 

 operation is the tying off, temporarily, of one of the blood vessels 

 in order to lessen the amount of the secretion reaching the blood. 



