Originally published in C. B. Acad. Sci., PaHf> 179, 291 (1924). 



17. RADIOCHEMICAL METHOD OF STUDYING THE 

 CIRCULATION OF LEAD IN THE BODY 



I. A. Christiansen, G. Hevesy and Sv. Lomholt 



Fi-om the Institute of Theoretical Physics, University of Copenhagen 



At the meeting of the Academy on 7 April 1924 we presented some work 

 performed by a radiochemical method on the circulation of bismuth in 

 ihe body. Since then we have used the same method for some experi- 

 ments on the circulation of lead, the first results of which are presented 

 here. 



In using bismuth in medicine it is of very great importance to know 

 the rate at which the bismuth injected into the body is distributed and 

 eliminated. This question can be resolved by using a substance with a 

 quite short half-life (5 days), such as radium-E. It is quite different in 

 the case of lead, since all the medical interest in this element centres 

 around the chronic poisoning which is caused gradually by the absorp- 

 tion of small quantities of lead during a long period of time. This is the 

 reason why we have used radium-D (half-life 20 years) in our experi- 

 ments, whereas Hevesy, in his experiments on the distribution of lead 

 in plants^i\ obtained satisfactory results with another isotope of lead. 

 thorium-B, having a half-life of only 11 hr. 



Since radium-D emits only soft /3-rays, which are difficult to measure 

 with the electroscope, we have counted the ^-radiation of radium-E in 

 equilibrium with the radium D and, consequently, have measured the 

 various products of analysis only at the end of several weeks. 



The experiments were performed on rabbits and guinea pigs. The 

 method described previously has been modified slightly: Instead of 

 evaporating the solution of the organic matter, which is decomposed 

 by means of nitric acid (or potassium permanganate in acid solution), 

 it is diluted, treatcfl with 100 mgm inactive lead nitrate, and lead sulphide 

 is precipitated. After filtering at the pump on a plane filter, the dried 

 filter is placed in a petri dish and the activity of the deposit is finally 

 determined. 



One example^ only is given here from our experiments. The lead hydrox- 

 ide, mixed with olive oil and a little carbon black, contained a quantity 



1. G. Heve.sy, Biochem. J. 17, 441 (1923). 



