284 Glycogenic Changes in the Placenta, etc., of the Rabbit. 
percentage of glycogen in the foetal organs reach the average amount found 
in adult tissues. 
- There is a distinct parallelism between the growth of the feetus and the 
percentage amount of glycogen which it contains. In two cases where growth 
had been spontaneously arrested, the percentage amount of glycogen in the 
foetal organs was diminished out of proportion to the diminution in weight. 
A similar condition could be reproduced experimentally by repeated 
injections of phloridzin. 
_ The interpretation of these results has led to conclusions which may be 
summarised as follows :— 
The placenta of the rabbit has the function of depositing glycogen as 
a store of carbohydrates for the needs of the foetus. The glycogen is 
absorbed from the maternal placenta in the form of a simpler carbohydrate. 
This transformation takes place in the placenta and is brought about by the 
action of an enzyme secreted by the placenta. 
--In the earlier stages of intra-uterine life the foetal liver is devoid of the 
power of storing glycogen, which it does not acquire until the last week of 
gestation. Before that date the placenta vicariously fulfils the hepatic 
function as far as glycogen is concerned. The glycogen metabolism of the 
placenta and the foetus is independent of that of the mother, and appears to 
be’ governed by conditions different in many respects from those which 
_ regulate the glycogen metabolism in the adult animal. 
There is a distinct relation between the glycogen metabolism and the 
growth of the foetus. Since the growing tissues of the foetus are not dis- 
tinguished by an abundance of glycogen, a definite formative power cannot 
be attributed to glycogen gud glycogen. The function of glycogen in the 
development of the foetal rabbit is probably to furnish material, on the one 
hand, for the intense carbohydrate metabolism that proceeds in the foetus ; 
and, on the other hand, for the building up of the protoplasm of fcetal 
tissues. 
The expenses of this investigation were defrayed by grants from the Moray 
Fund of the University of Edinburgh. 
