470 ADVENTURES IN RADIOISOTOPE RESEARCH 



Comment to paper 48 



Urey's disco\eiy of heavy water was bound to impiess the tracer-minded scien- 

 tists, ahhough their number was very lestricted in those days. The present writer 

 at once approached Professor Urey who most generously mailed a few litres 

 of water containing 0.5 mol. per cent heavy water. In view of the great sensi- 

 tivity with which the density of water can be determined, this stiongly diluted 

 heavy water sufficed to study the interchange between the water molecules of the 

 goldfish and the suriounding water, and also to carry out studies described in 

 paper 48, and presented more in detail by Hevesy and Hofer (1934). Within 

 1 hr an almost quantitative interchange between the water molecules of the 

 fish and those of the surrounding water was found to take place. The amount of 

 deuterium incorporated into the organic components of the fish, compared with 

 the amount of deuterium entering as deuteriated water into the fish, was found 

 to be small. The present writer intended, if successful in obtaining more 

 concentrated heavy water, to study this type of incorporation. Shortly after- 

 wards, ScHOENHEiMER and Rittenberg embarked on the study of this problem 

 and solved it in a masterly way (cf. p. 403). The discovery of artificial radio- 

 activity induced the present writer to abandon his original plans and to find 

 out if and to what extent the mineral constituents of the skeleton are in a dyna- 

 mic state cf. Radioactive Indicators in the Study of Phosphorus Melambolism 

 in Rats. 



In paper 48 it is stated that the goldfish behaves in the same way in the heavy 

 water employed in the experiments described as in tap water, though it may 

 behave differently in more concentrated heavy water. In experiments with 

 Haggkvist carried out in recent years (1958), we found that the life-span of the 

 fish investigated was reduced from years to 10 days when kept in 40 per cent 

 heavy water. When the fish were placed in 50 per cent heavy water, they tried 

 to escape by jumping out from the vessel in which they were kept. 



When our paper on the interchange of the water molecules of the goldfish and 

 those of the suirounding water was published, Urey had not yet proposed a name 

 for heavy hydrogen, while Rutherford discussed the possibility of calling it 

 diplogen. This explains why we chose "Diplogon and fish" as the title of our paper. 



References 



G. Hevesy and E. Hofer (1934) Z. Physiol. Chem. 225, "28. Received by the 



Editor on 20 March 1933. 

 G. Haggkvi.st and G. Hevesy (1958) Acta Radiol. 49, 321. 



