28 GLANDS IN HEALTH AND DISEASE 



"goiter"), and a pressure is exerted on neighbor- 

 ing glands such as the trachea and esophagus. The 

 enlargement of the thyroid gland would lead one 

 to suspect that there is a hyper-, rather than a hypo- 

 secretion of the hormone. This, however, is not 

 true of this type of goiter, which is quite prevalent 

 in Switzerland, and in the Lake sections of our 

 country (hence called "endemic" to denote its local 

 character) . That we here deal with a type of hypo- 

 secretion is made evident by the general symptoms 



Thyroxin is 4,5,6 tri-hydro-4,5,6 tri-iodo-2-oxy-beta indolepro- 

 pionic acid 

 I H 



V 



H H 



c-J-A-o' 



OH 



It is a colorless, odorless, crystalline substance, insoluble in 

 aqueous solutions of all acids, including carbonic; soluble in 

 sodium, potassium and ammonium hydroxides; slightly soluble 

 in sodium and potassium carbonates. It forms salts with metals 

 and acids. It contains 65 per cent, of iodine. 



The above formula was established by an analysis of the sub- 

 stance, and by a study of its derivatives. 



An interesting observation, made by Dr. Dutcher, but not yet 

 confirmed, so far as I am aware, is to the effect that thyroxin 

 has vitamine properties; it behaves like yeast, for example, in 

 curing birds of polyneuritis and men of beriberi (see the chapter 

 on Beriberi in the author's book on Vitamines). Are we after 

 all on the eve of discovering some relationship between vitamines 

 and hormones? 



