662 ADVElf.TURES IN RADIOISOTOPE RESEARCH 



E. F. Latham and G. J. Vosburgh, cf. G. J. Vosburgh and L. B. Flexneb 

 (1950) Amer. J. Physiol. 161, 202. 



F. LoBBER (1927) Biochem. Z. 181, 391. 



A. Mazur, S. Baez and E. Shorb (1955) J. Biol. Chem. 213, 417. 

 H. Stebn, V. Allfrey, A. E. Mirsky and H. Saetren (1952) J. gen. Physiol. 

 35, 559. 



G. J. Vosburgh and L. B. Flexner (1950) Amer. J. Physiol. 161, 202. 

 F. WoHLER (1955) Dtsch. med. Wschr. 30, 



Comment on paper 66 



As already shown by Vosburgh and Flexner (1950) the ^^Fe introduced into 

 the maternal plasma of pregnant guinea-pigs is soon detectable in the embryos. 

 In paper 66 it is shown that about % day after labelling of the maternal plasma 

 iron 1 gm of foetal hver contains 143 times more ^'Fe than does the same weight 

 of the maternal hver. In the former about 80 per cent of the ^^Fe which passed the 

 placenta accumulates, demonstrating conspicuously the fact that in the rabbit 

 embryo the Hver is the main haemopoietic organ. Exposure of the rabbit to 500 r 

 increases the amount of ^^Fe passing the placenta to twice the value in non-exposed 

 animal. This is a result of the higher plasma ^^Ye concentration of the maternal 

 plasma in the exposed animal. (1959) It was recently found by us that the 

 maternal ^^Fe which reaches the mouse foetus is much better conserved during 

 life than ^^Fe injected into the mouse intraperitoneally. ^/g ^j^ per day is lost 

 daily from the former, i/g ^j^ from the latter 



Reference 



G. J. Vosburgh and L. B. Flexner (1950) Amer. J. Phijsiol. 161, 202. 

 G. Ehrenstein and G. Hevesy (1959), Acta Haematol. 22, 311. 



