in the starch columns, it seemed necessary to determine the circumstances introduced variability in the paper system. Interchange of the isotopic label again proved to be a serious objection to the method when an acid m@dium was used. The shift to ammonia in a butanol solvent resolved problems of Jinterchange. solubility of water in butanol. The removal of excess water (by separatidn) at the lower temperature and the return of the solution to room temperature made chromatography procedure very reproducible. The separation of all the compounds was surprisingly clean. determinations on the serum and urine of a patient in a period of a few we led to a very extensive study of serial quantitative chromatograms on blocf days and weeks after a treatment dose of 151I had been given. These studies will be described in a later section of this report. Cellular Changes in Human Thyroids Treatedwith 1317 During the late 1940's the responsible investigator became interest bizarre mucleatforms found in thyroids of some patients who had previous treated with Since the responsible investigator is a surgeon, a unique Sprortunity to procure samples of previously irradiated thyroids ufder very strict experimental conditions, indication for surgery usually being the refoval of residual masses. With the timing of the procurement of the sample followi P Supervision doses of 131] and the analyses being carried out in the laboratory under of the same person who designed the experimental protocol and procured the samples of tissue, it has been possible not only to obtain, with precise timing, tissug out special histological techniques but also to observe the synthesis of th hormone by these irradiated glands. At the time of the move from Boston tofCleveland a total of 29 tmman thyroid tissues had been collected. Although much of the work had been done under the former contract in Boston, the preparation of the materjal and of the publication was accomplished later. The most important observation in fhis study of radiation effects was the large, bizarre nuclear forms that appeared in fhe human thyroids long after the radiation fron 131I was gone. Dobyns, B.M., Vickery, A.L., Maloof, F., and Chapman, E.M.: Functional and[Histological Effects of Therapeutic Doses of Radioactive Iodine on ths Thyroid of Man. Endocrinol. & Metab. 13: 548-567, 1953. gf. Clin. Early Radiation Experiments to Study Changes in Cellular Structure and Function in Animals When the bizarre nuclear forms were first discovered in man, animal e were designed to observe long and short term effects of radiation in thyroi given various doses of 131,.° More than 200 young rats were injected with v. doses of 1317 ranging from 1 pe to 300 uc. The uptakes were determined, an subsequent functional nature of the thyroids studied. This study became effort of Dr. Farahe Maloof who was a co-worker and now the head of the th laboratory of the Massachusetts General Hospital. Graded impairment to demonstrated in the animals. See Figure 5. The two mst interesting histo in these thyroids following irradiation were a persistent increase in cell thyroid epitheliun even in the slightly irradiated giands and the bizarre n as had been seen in some of the human material. The increase in cell height], which was thought to reflect an endogenous stimulus from the animal's pituitary resulting from