21 6 ADVEXTURES IX RADIOISOTOPE RESEARCH 



which participates in a renewal process determined, information on more detailofl 

 processes taking place in the skeleton were available only after the introdviction 

 of the autographic methods of investigation in this type of study by Leblond 

 ei al. (1951). 



The 32p applied in our early investigations was prepared under the action of 

 neutrons emitted by radon-beryllium sources on 10 1. of CS^, the ^'^P being ex- 

 tracted by strongly diluted acid. On his fiftieth birthday, Professor Niels Bohr 

 was presented by his friends with 600 mgm of radium, which he most generously 

 put at our disposal. It was the Union Haute Miniere which supplied the radium 

 as sulphate mixed with 2 gm of beryllium. In view of the hygroscopicity of RaCl, 

 the Union Haute Miniere was at that early date not willing to supply RaCl2- 

 beryllium mixtures. After the availability of cyclotron-produced ^^p^ Professor 

 Ernest Lawrence most kindly repeatedly mailed to us, starting in 1937, a few 

 miUicuries of ^^p prepared by Dr. Martin Kamen. This was a very great help, 

 as was 32p supplied later by Professor Bohr's and Professor Siegbahn's cyclotron. 



In paper 19, published in 1937, the first clinical investigation is describee] 

 in which a radioactive isotopic indicator was applied, the determination to what 

 extent the phosphorus of the faeces is of endogenous origin and the investigation 

 of the incorporation of ^-P into the placenta. Paper 20, published in the same 

 year, contains data on the incorporation of ^^P into humarr teeth, both into roots 

 and crowns. Deuterium, thus a stable isotopic indicator was formerly used (paper 

 54) in the determination of the water content of the human body. In 1937 Hamil- 

 ton published a study on the rate of absorption of sodium by fasting human 

 subjects following the oral administration of labelled sodium. Borsook et al- 

 described in the same year the excretion by human subjects of administered ^^S. 



References 



C. P. Leblond, G. W. Wilkinson, L. F. Belanger and J. Robison (1951) 

 Amer. J. Anat. 86, 289. 



H. Borsook, S. Keighley, D. N. Yost and E. McMillan (1931) Science 86, 

 525. 



J. G. Hamilton (1937) Proc. Nat. Acad. Sci. U. S. 23, 521. 



