MERCURY 209 



was dried, and the filter-paper mounted to a metal disk with rubber 

 cement for end-window counting. In another study (IIg-3) both Na-- 

 and a Hg^^Mabeled mercurial diuretic were added to the same filter-paper 

 disk as above. It was shown that heating of the disk at 250°C for 80 min 

 was sufficient to drive off almost all the Hg^"* without change in the Na-- 

 activity. This procedure was suggested for use in double-labeling studies 

 with the two radioisotopes. In a study with rats (Hg-4), 1 mg Hg in 

 HgCl2 containing 50 fxc Hg-"^ was injected intravenously. Kidney sec- 

 tions were fixed in 10 per cent Formalin in 0.85 per cent NaCl solution, 

 embedded in paraffin, and cut at a thickness of 8 fi. Exposures were 

 made on 10- and 25-^1 emulsions with 8 to 15 million beta particles per 

 square centimeter employing Eastman Kodak NTB nuclear-track plates. 

 After development, the paraffin sections were stained with hematoxylin 

 and eosin for microscopic examination. 



Hg-l. Cholak, Jacob, and Donald M. Hubbard: Microdetermination of Mercury in 



Biological Material, Ind. Eng. Chem. Anal. Ed., 18: 149-151 (1946). 

 Hg-2. Burch, George, Paul Reaser, Thorpe Ray, and Sam Threefoot: A Method of 



Preparing Biologic Fluids for Counting of Radioelements, J. Lab. Clin. Med., 



35: 626-633 (1950). 

 Hg-3. Reaser, P. B., G. E. Burch, S. A. Threefoot, and C. T. Ray: Thermal Separation 



of Radiomercury from Radiosodium, Science, 109: 198 (1949). 

 Hg-4. Lippman, Richard \V., Raymond D. Finkle, and Dale Gillette: Effect of 



Proteinuria on Localization of Radiomercury in Rat Kidney, Proc. Soc. Exptl. 



Biol. Med., 77: 68-70 (1951). 



