HORMONES 45 



pancreas. The two lobes of the thyroid are 

 united across the front of the windpipe by a 

 narrow band of their own substance, the so- 

 called isthmus. The thyroid gland is inti- 

 mately associated with a group of glands, the 

 parathyroids, whose presence was not always 

 recognized by the earlier investigators. Some 

 of the confusion which entered into the ear- 

 lier physiological work on the thyroid was 

 probably due to the accidental removal of the 

 parathyroids with the thyroid, a condition 

 which leads to very different results from 

 those observed in the simple removal of the thy- 

 roid itself. The circumstances which brought 

 about an investigation of the thyroid may now 

 be briefly stated. 



In any large community individuals appear 

 from time to time who from childhood on fail 

 to grow and develop. They therefore are of 

 dwarfish stature, their hands are large and 

 misshapen, their features dull and expression- 

 less. All these signs, together with the actions 

 and habits of such individuals, give the im- 

 pression to the casual observer of low mental 

 capacity, if not idiocy, and such in truth is 

 their real state. As members of society they 

 are usually more or less helpless and are either 



