538 THE PHYSIOLOGY OF REPRODUCTION 



in the- human female (Charrin and Guillemont ^). ■ But since the 

 amount of glycogen varies greatly and is dependent to a large extent 

 on the diet, it is difficult to establish with certainty that there 

 is an increase. Harding,^ on the other hand, postulates a greater 

 tendency to a deficiency of glycogen in the maternal liver and 

 associates this deficiency with the morning ' sickness of women and 

 even with pernicious vomiting. This view is based on the work of 

 Bohr and of Lochhead and Cramer,* who showed that the presence 

 of the foetal cells imposes a special demand for carbohydrates on the 

 maternal organism. The pregnant woman has therefore a greater 

 tendency to pass into a state of specific carbohydrate starvation 

 than the non-pregnant woman. The important practical application 

 of this fact will be discussed in greater detail below (see p. 544). • 



The placenta contains glycogen in amounts which vary greatly in 

 different species.* It is found only in traces in Ruminants, but 

 in great amount in Rodents (see Chapter X., p. 460). It occurs 

 also at the margin of the zonary placenta in Carnivores, and in the 

 human placenta. In many species it has not yet been investigated. 



In the foetus, the feature of the glycogen is not its high 

 percentage, but its almost universal distribution in the developing 

 tissues.* It has been shown by Bohr that the energy in the 

 mammalian foetus is supplied by the combustion of carbohydrates 

 (see p. 553), and by the wide distribution of glycogen an available 

 supply is procured in every part of the ftetal body in which the work 

 of organisation is proceeding. 



(fi.) The Daily Requirement of Garbohydrafe for the Foetus. — Some 

 idea can be obtained of the daily requirements of glycogen for the 

 foetus of the rabbit in the second half of pregnancy. The appended 

 table, from the paper of Lochhead and Cramer,^ gives the amount of 

 glycogen contained in the unborn young from the eighteenth day 

 of gestation till the day before parturition. 



The table shows that V2 gm. of glycogen are deposited between 

 the eighteenth and the twenty-eighth day, or about 0'2 gm. per foetus. 

 Hence the average daily deposition is 0-02 gm. per foetus. In the later 

 stages the rate of depQsition increases out of proportion. This is due 

 to the assumption of its glycogenic function by the foetal liver. 



^ Charrin and Guillemont, "Physiologie pathologique de la Grossesse," 

 Gompt. Rend. Soc. Biol., 1899. 



2 Harding, "Nausea and Vomiting in Pregnancy," The Lancet, vol. ccL, 1921. 



' Lochhead and Cramer, " The Glycogenic Changes in the Placenta and the 

 Fcetus of the Pregnant Ea,bbit," Proc. Roy. Soc. London, B., vol. Ixxx., 1908. 



* Gierke, "Glycogen in der Morphologie des Zellstoffwechsels," Habilitations- 

 schrift, Freiburg, 1905. } 



° Lochhead and Cramer, " The Glycogenic Changes in the Placenta and the 

 Foetus of the Pregnant Rabbit," Pron. Roy. Soc. London, Ser. B., vol. Ixxx., 1908. 



