deal of Ais time to enwtining thyreiis, judges and records the charafter of the clané at physical examination and then nerscnally reviews the histology cnfleach cland the: is operated snould be able to correlate the physical findings with the histology with reasonable accuracy. 131 We believe that we have shown in these studies why the dose of 1g: ; , , , I produces prompthypothryoidism in some patients and is relative others. ineffective in The calculated dose to be taken up by the gland may be modified to fit the circumstances. Similarly the physician who records his preoperativa estimate of the thyrcid weight and then sees and weighs the amount of tissue remov , has performed a unique control of his ability to estimate accurately the weight of the thyroids. With experience he can refine his judgement of weight for those to fe treated with 131, Qur data to be collected on the clinical features of the gland in patients before treatment with 131 I have been assembled on index cards so that many of these considera- tions have been explored in the light of the thoroughly studied cli nical result. If a more precise estimate of the dose of 13 ty that is needed can be athieved, then perhar there can be more correct doses given, fewer early developments of hypothyroidism and fewer instances of repeated treatments being required. The Kinetics of Various Treatment Doses of 131) The collection of data on the changing pattern of 131 I iodina amino acids and free iodide in the serum and urine and the disappearance of 131; fr om_«the thyroid fol- lowing treatment doses for hyperthyroidism has been mentioned. Sex hal measurements of iodinated compounds were carried out by quantitative chromatography almost daily for weex and weekly for several weeks. Studied. There are over 175 Graves' dis The quantitative data on blood and urine along with esti se patients so ted weight of the gland, the size of the dose given, the size of the dose lodged fin the gland and finally the features of the clinical response that followed weqe given to Dr. A.B. Brill (formerly of Vanderbilt University) for analysis. have been studying and analyzing this material in compartmentalizeq e and his associat models originally <