82 



A. Neuberger 



Thorell, B. (1947). Acta med. Scand., 129, Suppl. 200. 

 Wittenberg, J., and Shemin, D. (1950). J. biol. Chem., 185, 103. 

 ZiLVERSMiT, D. B., Enteman, C, Fishler, M. C, and Chaikoff, I. L. 

 (1943). J. gen. Physiol., 26, 333. 



DISCUSSION 



Thorell: As a consequence of earlier microspectrographic studies 

 on endocellular haemoglobin formation, we have been interested in the 

 time sequence of the formation of globin and haemin during erythro- 



% immature 

 in blood 



e marrow 



Bon 

 mitosis frequency 



00 



\<5-10"'2 Hb 



20 



10 



t t tt 



Hemolysis Hen I 



hou 



rs 



Fig. 1. Haematological changes in hen after injection of phenyl- 

 hydrazine. Abscissa: time in hours. The curve with circles 

 represents the mitosis frequency in the bone marrow. The dotted 

 curve shows the relative amount of erythroblasts in blood, 

 containing ca. 5 per cent haemoglobin as determined micro- 

 spectrophotometrically. The full curve represents erythro- 

 blasts with no haemoglobin. The arrows indicate the injections 



of labelled glycine. 



poiesis. I would like to show one of the experiments done in collabora- 

 tion with Dr. Hammarsten and his group. 



We have used hens, and in order to get a rapid formation of haemo- 

 globin, the hens were made anaemic by haemolysis with phenylhydrazine. 

 After this treatment a rapid regeneration of red cells could be observed 

 (Fig. 1). As shown by cytological analyses, during this condition the 

 erythropoiesis is divided into two parts: the growing, dividing cells are 



