FCETAL NUTRITION: THE PLACENTA 503 



Glycogen 



Glycogen is present in the early stages of pregnancy. Langhans ^ 

 demonstrated it in the decidual cells, in the cellular proliferations of 

 the trophoblast at the tips of the villi, and in the mesoblast. It was 

 absent in the canalised fibrin and Langhans' layer. Merttens ^ also 

 found it in the decidua near the ovum. Driessen ^ states that it is 

 present in the superficial and glandular epithelium of the uterus in 

 the first month of pregnancy ; around the ovum " in cells of doubtful 

 origin " glycogen is plentiful, but absent in the deeper parts of the 

 decidua ; in the villi it is not found in the syncytium and Langhans' 

 layer, but is present in the cell-islands at the tips of the villi, and 

 occasionally in the mesoblast. The total amount is, however, much 

 smaller than in Eodents, and represents only about 0'08 per cent, by 

 weight (Cramer*). 



Fat 



' Fat was first described in the human placenta by Apfelstedt and 

 Aschoff.^ They found it du.ring the second month of pregnancy in 

 the syncytium and Langhans' layer, and in the decidual cells near 

 the villi. Eden*^ found fat in "the perinuclear protoplasm of the 

 syncytium, and m Langhans' layer and the stroma of the villi. It is 

 also present in the capillary walls (Dastre''), The appearances 

 suggested to Eden that " the placenta appears to be a storehouse of 

 nutritive fat just as is the liver." Minute discrete droplets were also 

 present in tjie decidual cells, and by tlie sixth month they had 

 increased in number. At full time the serotina still contained fat, 

 but " it is doubtful whether now it is a physiological deposit, as the 

 serotina shows many degenerative changes." At the same time, a 

 fatty degeneration of the decidua is probably pathological and n(jt a 

 constant phenomenon (Klein**), and the fat globules in the early 



maternal blood channels and in the ' glands of the uterine mucosa. " (Wislocki 

 and Key, "The Distribution of Mitochondria in the Placenta," ConPnbutioTis 

 to Emh-yology, vol. xiii., Carnegie Institute (Washington) Publication No. 276, 

 1921.) 



' Langhans, "Ueber Glykogen in pathologischen Neubildungen und den 

 menschlichen Eihauten," Virckow'a Arch., vol. cxx., 1890. 



^ Merttens, " Beitrage zur nprmalen und pathologischen Anatomie der. 

 menschlichen Placenta," Zeitsch. f. Oeh. v. Qynak., vols. xxx. and xxxi., 1894-95. 



^ Dries.sen, " Ueber Glykogen in der Placenta," Arch. f. (h/nal:, vol. Ixxxii., 

 1907. 



^ Cramer (A.), "Beitrage zur Kenntnis des Glykogens,'' Zeitsch. f. Biol., 

 vol. xxiv. 



* Apfelstedt and Aschoff, " Ueber bosartige Tumoren der Chorionzotten," 

 ArcLf. Oyiiak., vol. L, 1896. 



" Eden, " The Occurrence of Nutritive Fat in the Human Placenta," Pmc. 

 Roy. Soc. London, vol. Ix., 1896. 



' See Eichet's Dictioinmirc rfe Physiologic, vol. vi., Article " IToetus." 



* Klein, " Entwicklung und Riic'kbildung der Decidua," Zeitsch. f. O'eburt.sh. 

 u. (lyntik:, vol. xxii. 



