33 2 PHYSIOLOGICAL CHEMISTRY. 



as is well known, complete removal of the bodies is usually 

 attended with fatal results, and Addison's disease is associated 

 with certain pathological conditions in the organs. Lecithin 

 bodies and a glucose furnishing complex are present in small 

 amount, as well as the mass of protein substance which has 

 not yet been fully investigated. 



THE THYROID GLAND. 



The relation of this gland to certain pathological conditions 

 which sometimes appear in man and which may be induced 

 in animals has been a subject of study for many years. At- 

 tempts to isolate the active principle or principles on which 

 the functions of the gland depend have been in a measure suc- 

 cessful. In the course of investigations a number of basic 

 bodies have been separated, but these may have no connection 

 with the observed physiological behavior. 



From the investigations of Oswald, who has made the full- 

 est contributions to the literature, there are two peculiar pro- 

 tein bodies present, one of w r hich is a globulin and the other 

 a nucleo proteid. To the first he has given the name thyreo- 

 globulin; this exists frequently combined with iodine, and it 

 is the latter complex which is theoretically and practically 

 important. It has been called iodothyreo globulin and appears 

 to be found only in those glands which contain colloid, and 

 the amount of iodine present is proportional to the amount of 

 colloid. The normal gland weighs usually 30-45 grams, in 

 which the thyreoglobulin fraction is in the mean about ten 

 per cent. The amount of iodine is usually less than one-tenth 

 of one per cent of the whole. In case of enlarged glands 

 goitre the whole organ may weigh up to several hundred 

 grams. If the goitre is rich in colloid the iodine appears to 

 be absolutely, but not relatively, increased. In the thyreo- 

 globulin from a normal gland over 0.3 per cent of iodine has 

 been found, while in the preparation from colloid goitres the 

 amount in the mean is 0.060.07 per cent. 



By treatment with acids the gland, or the thyreoglobulin 



