THE THYROID 15 



abnormally. The fluid, or still better, the active 

 hormone that the body secretes, is under certain 

 conditions largely increased. We get then a con- 

 dition of hyper-thyroidism. The disease known as 

 "exophthalmic goiter" (Graves's disease and Base- 

 dow's disease are synonyms) is probably a case in 

 point. On the other hand, a condition may arise 

 wherein the quantity of secretion and the supply 

 of hormone become deficient. This may develop 

 "myxedema" in the adult and "cretinism" in the 

 infant; such being examples of hypo-thyroidism. 

 We shalltake these up in turn, and we shall begin 

 with hypo-thyroidism. 



Eypothyroldlsm. In medicine definite clues as 

 to the type of disease are usually obtained by pre- 

 liminary experiments with animals. We find that 

 as early as 1859 Schiff, a Swiss physiologist, in- 

 vestigated the effect of thyroidectomy on animals 

 ( "thyroidectomy" is a convenient word to describe 

 the idea of the surgical removal of the thyroid. 

 "Dectomy" is derived from a Greek word meaning 

 "excision.") His results, though suggestive, were 

 inconclusive, due to the fact, as we know to-day, 

 that Schiff removed the parathyroids as well as 

 the thyroids. But this physiologist went a step 

 further. Having removed the thyroid, he next in- 

 vestigated the effect of implanting thyroid from an 

 animal of the same species. The results in a num- 

 ber of cases were highly encouraging. 



