Foetal Haemoglobin and Rli. Antagonisms 



only conclude that foetal and later haemoglobin are present in different 

 blood corpuscles, the corpuscles filled with foetal haemoglobin being 

 broken down more rapidly than those containing later haemoglobin. 

 This is in agreement with the observation of Mollison who found that 

 a part of the red blood corpuscles present at birth was broken down 

 more rapidly than the rest. 



100 

 90 

 80 i 



.o 



X 70 



S 60 



^ 50 



c^ „„ 

 S 40 

 c 



ij 30 



^ 20 

 10 



2 4 6 8 10 12 14 16 18 20 22 

 Time in Weeks 



Figure 4. The disappearance of foetal Hb from the blood 



in full term and prematurely born children. Vertical axis : 



the percentage of Hb which has still the foetal form. 



At the moment of birth prematurely born babies have less later 

 haemoglobin than full-term babies, but even in early prematures traces 

 of later haemoglobin can nearly always be detected. In prematurely 

 born children foetal haemoglobin disappears later than in children 

 born at term. Nothing is known about the site of formation of later 

 and foetal haemoglobin. It may be suggested that later haemoglobin 

 is formed in the bone-marrow and foetal haemoglobin in the liver, 

 but I have never been able to find any difference between the percen- 

 tages of foetal and later haemoglobin at these sites. 



It is not clear how the organism can change at a given moment 

 from the production of one form of haemoglobin to that of another. 

 The presence of small amounts of later haemoglobin in the blood of 

 early premature infants makes it probable that later haemoglobin is 

 from the beginning made in small amounts at the same sites as foetal 

 haemoglobin. 



I have had the opportunity of making determinations of the per- 

 centage of foetal and later haemoglobin in some children suffering 

 from erythroblastosis, due to Rhesus antagonism. Two of these 

 children did not get any special treatment. At the moment of birth 



265 



