120 



A. St. G. Huggett 



weight was calculated it was seen that a relative anaemia 

 was produced (Fig. 3). This, however, was not due either to 

 shortage of iron or inefficiency of the placenta but to the foetal 

 growth being disproportionate. 



At the risk of overlapping with Professor Wislocki's 

 approach, one would draw attention to the weights of the 

 human placenta given in Adair and Thelander's classical 

 paper in 1925. In no case is there any suggestion that the 

 placenta loses weight as the foetus grows (Fig. 4). In the goat, 

 however, Elliott, Hall and Huggett (1934) found evidence of 



100 



90 



80 



70 



*o 60 



3? 50 



I" 40 



30 



20 



10 







Pregnancy 



Lactation 



\. 



14 



14 

 Days 



21 



28 



35 



42 



Fig. 3. Ratio Iron/Weight in foetal and newborn rats. (Huggett and 

 Widdas, 1949.) 



a slowing up or flattening out of the placental weight curve. 

 On the other hand, umbilical blood flow through the placenta 

 in the foetal sheep has been shown to rise rapidly as term 

 approaches (Fig. 5) (Cooper, Greenfield and Huggett, 1949). 



When considering the production of materials by the 

 placenta one should draw attention to the production of 

 carbohydrates within it. Mammalian allantoic placentas can 

 be divided into two classes, those whose foetal blood has one 

 sugar, glucose, and those whose foetal blood has two, glucose 

 and fructose, and in these, fructose is always in excess. These 

 latter are all Ungulata or Cetacea. Glucose can flow back to 

 the mother if the gradient is reversed experimentally but 

 fructose never does. This fructose is synthesized by the 



