214 ADVENTURES IN RADIOISOTOPE RESEARCH 



molecular layer of the bone crystallites and the phosphate of the plasma» 

 and. partly the effect of a "biological recrystallization". Crystallites 

 or parts of crystallites go into solution and new crystallites are wholly 

 or partly formed by crystallization from the plasma. In experiments 

 of long duration, the interchange mostly takes place by biological recrys- 

 tallization. Now, such a process may be expected to be strongly influen- 

 ced by the body temperature and to take place at a higher rate at 37° 

 than at 16°. 



It is interesting to note that in experiments of only a few hours' 

 duration, increase of temperature was found to promote the radio - 

 phosphorus uptake by the bones. The tibia of the frog (Hevesy et al. 

 1940) was fo«nd to take up nearly II/2 times as much radio-phosphorus 

 at 22° as at 0°. 



We found that a fish weighing about 1 gm took up, in the course of 16 

 days, 1/4- 10* part the phosphorus added to the water i. e. 2- 10~^ mgm. 

 As the water volume was 3000 ml., the amount of P taken up by the 

 fish from water is equivalent to the amount of P present in 1/13 ml water. 

 The amount of water taken up by the fish in the course of 16 days is 

 presumably much larger than 1/13 of its body weight (cf. p. 206) and, 

 thus, only a minor part of the P content of the water swallowed is absor- 

 bed. 



Summary 



Sticklebacks (Gasterosteus aculeatus) were kept for periods of up to one month 

 in 3 litres of sea-water containing labelled phosphate. A fish weighing 1 gm was 



found to take up in the course of 16 days part of the phosphorus present in 



the water, corresponding to 2 • 10"^ mgm P. 



By comparing the specific activity of the skeleton P with that of the free livei- 

 P, figures for the degree of the renewal of the skeleton were obtained. At least 

 95 per cent of the skeleton were found to remain unchanged during the experiment. 

 The rate of renewal of the fish skeleton is thus much lower than that of the maiuma- 

 lian skeleton. 



References 



G. Hevesy and L. Hahn (1938) Det Kgl. Danske Vid. Selsk. Biol. Medd. 14. 1. 

 G. Hevesy, H. Levi and O. Rebbe (1940) Biochem. J. 34, 532. 

 G. Hevesy and O. Rebbe (1940) Acta Physiol. Scand. 1, 171. 

 K. Kjerulf-Jensen and E. Lundsgaard (1943) Ibid. 7, 209. 

 A. Krogh (1939) O.smotic Regulatio?i in Aquatic Animals. Cambridge. 

 R. S. Mani.y, H. C. Hodge and M. Le Fevre Manly (1940) J. Biol, f'hcni. 

 134, 293. 



R. Robison The Significance of Phosphorus Esters in Metabolism. New York. 

 I. Roche and M. Mourgue (1939) Bull. Soc. Chim. Biol. Paris 21, 143. 

 F. Roth (1920) Anatom. Anz. 52, 513. 

 H. W. Smith (1930) Awer. J. Phij-nol. 93, 480 (1931): Ibid. 8, 269. 



