508 THE PHYSIOLOGY OF REPRODUCTION 



abortion in certain animals on a diet containing them in excess 

 (see p. 495). 



b. Carbohydrates of the Maternal Organism. — Lactose may- 

 appear in the blood in pregnancy as well as during the lactation 

 period. Laevulose is not present in the serum of a healthy 

 animal ; but it is normally present in the allantoic fluid of the 

 cow (Giirber and Griinbaum ^), and in the blood-serum of the 

 foetal rabbit, cow, and sheep (Paton ^). Whether it is the only 

 monosaccharide present has not yet been determined, but it is in 

 sufficient amount to render the serum Isevo-rotatory. 



The glycogen store of the Hver is stated to be increased in 

 pregnancy in the dog (Burlando ^), in the guinea-pig (Maurel *), 

 and in the human female (Charrin and Guillemont ^). There is 

 no increase in the rabbit. The placenta contains glycogen in 

 varying amounts. It is found only in traces in Ruminants, but 

 in great amount in Rodents (see Chap. X., p. 431). 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 investi- 

 gated. 



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

 percentage, but its almost universal distribution in the de- 

 veloping tissues.^ It has been shown by Bohr that the energy 

 in the mammahan foetus is supplied by the combustion of 

 carbohydrates (see p. 518), and by the wide distribution of 



' Giirber and Griinbaurn, " Ueber das Vorkommen von Lavnlose im 

 Fruchtwasser," Miinch. med. Woch., 1904. 



' Paton, Watson (B. P. ), and Kerr, "On the Source of the Amniotic and 

 Allantoic Fluids in Mammals," Trans. Roy. Soc. Edin., vol. xlvi., 1907. 

 The proof that the carbohydrate is Isevulose rests on the Isevo-rotation of 

 the plane of polarised light and the ketone reaction. Doubts have recently 

 been expressed regarding the sufficiency of these two tests. 



' Burlando, ' ' Behaviour of Hepatic Glycogen during Menstruation, 

 Pregnancy, Puerperium, and Lactation Period," Arch. Ital. di Oinec, 1906. 



^ Maurel, " Des d^penses albuminoides pendant la grossesse chez le 

 cobaye," Comp. Rend. Soc. Biol., vol. Ixi., 1907. 



* Charrin and Guillemont, " Physiologic pathologique de la Grossesse," 

 Comp. Rend. Soc. de Biol., 1899. 



° Gierke, "Glycogen in der Morphologie des Zellstoffwechsels," Habili- 

 tationsschrift, Freiburg, 1905. See also Lochhead and Cramer ("The 

 Glycogenic Changes in the Placenta and the Foetus of the Pregnant Rabbit," 

 Proc. Roy. Soc, Lgndon, Ser. B., vol. Ixxx., 1908), from whose memoir the 

 Table is copied. 



