CHAPTER III 



THE THYROID GLAND 



As a short introduction, I quote from Bainbridge's 

 Essentials of Physiology : " The thyroid gland 

 consists of two lobes, one on each side of the 

 trachea, united by an isthmus, and it is composed 

 of closed spherical vesicles, held together by con- 

 nective tissue. Each vesicle contains a viscid 

 colloid material. The thyroid gland contains 

 iodine in organic combination, and it has recently 

 been shown that the iodine is combined with 

 tryptophane to form tri-iodo-tryptophane. This 

 compound has been named thyroxin. The gland 

 is richly supplied with blood-vessels and nerves. 

 Numerous lymphatic vessels are often found, 

 and these sometimes contain colloid material." 



Probably this gland's chief function is the rule 

 of the body's metabolism. Even in health the 

 extract given internally increasfes considerably 

 the nitrogenous excretion, and it lowers blood- 

 pressure. If large doses are given, tachycardia with 

 irregularity more or less is produced, and nervous 

 excitability, flushing and heat of the skin with 



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