Relations Between Thyroid and Pituitary Glands, i i 



acidified solution of the product, the iodine occurring in animal 

 tissues may be quantitatively converted into iodic acid. After the 

 excess chlorine has been removed, addition of potassium iodide 

 leads to the liberation of exactly six times the original amount of 

 iodine. The iodine thus set free may be titrated directly with a 

 sodium thiosulphate solution of suitable strength. It is claimed 

 for the method that it excels the various forms of the Baumann 

 method, not only in cleanliness, convenience, and rapidity, but also 

 in accuracy. Details will be published as soon as a larger series 

 of control analyses is completed. 



7 (417) 



Relations between the thyroid and pituitary glands. 

 By Sutherland Simpson and Andrew hunter. 



\_From the Department of Physiology, Biochemistry and Pharma- 

 cology of the Cornell University Medical College, Ithaca, N. K] 



Recent work by Herring 1 has shown that complete removal 

 of the thyroid in rabbits, cats and dogs is followed by definite 

 histological changes in the pituitary body. A greatly increased 

 production of colloid material by the cells of the pars intermedia 

 was indicated. Accumulations of colloid were observed in the 

 nervous portion of the posterior lobe and in the laminae forming 

 the floor of the third ventricle whence it appeared to find its way 

 between the ependyma cells into the infundibular recess and brain 

 ventricles. 



It is believed by many that the iodine-containing substance 

 — the so-called iodothyrin or thyroiodin — is the active substance 

 of the thyroid gland. Reid Hunt states that the physiological activ- 

 ity of the thyroid varies directly with the percentage of iodine 

 which it contains. According to Baumann, Halliburton 2 and 

 others the pituitary yields no iodine. Gideon Wells, 3 from an 

 analysis of fourteen normal human pituitaries, found an average 

 amount of 0.0036 milligram of iodine for each gland — about 

 one fiftieth of the quantity found in the thyroid. Ox pituitary ob- 

 tained from Armour and Co. tested by Hunter's method gave no 



1 Quart. Jour, of Exper. Physiol., 1908, i, 281. 



2 Quart, Jour, of Exper. Physiol., 1 909, ii, 229. 



3 Jour, of the American Med. Assoc., 1897, xxix, 897, 954, 1007. 



