FCETAL NUTRITION: THE PLACENTA 481 



Hofbauer state that albumoses are present in the placenta, but 

 this is doubtful. In watery extracts Rielander ^ demonstrated 

 purine bases, uracil and choline, and in the autolysed placenta 

 leucine and tyrosine have been found (Basso ^). It is generally 

 held that such results prove an active metabohsm of protein in 

 the foetal placenta. 



Ferments. — Various enzymes have been investigated in the 

 placenta. They may be grouped according to the chemical 

 nature of the actions which they produce : — 



Hydrolytic Reactions. — A proteolytic enzyme was found by 

 Ascoli,^ and subsequently by Merletti,* Bergell and Liepmann,® 

 Savare,^ and others. Bottazzi ' states that placental tissue can 

 transform glycogen into maltose, and a similar action is strongly 

 produced by glycerine extracts of the maternal and foetal 

 placenta of the rabbit (see p. 434). 



Savarfe holds that the transformation of glycogen to sugar 

 is due to the blood ; but the fact that extracts of the ungulate 

 placentae, which also contain blood, do not possess the same 

 power, forces us to conclude that the enzyme activity in the 

 rabbit and Man depends on the placental tissue. No lipolytic 

 enzyme is present in the placenta (Charrin and Goupil ^). 



Oxidation Reactions. — The oxidation of aromatic aldehydes 

 by the placenta has been obtained by Hofbauer and by Ferroni,' 

 not by Savarfe or Charrin and Goupil. V. Fiirth and Schneider^" 

 state that tyrosine is oxidised by contact with the placenta, 



' Rielander, " Ein Beitrag zurChemie der Planenta," Centralbl. f. Oynak., 

 1907. 



^ Basso, " Ueber Autolyse der Placenta," Aroh. f. Oyndk., vol. Ixxvi. 



' Ascoli, " Passiert Eiweiss die placentare Soheldewand ? " Zeitschr. f. 

 phys. Chemie, vol. xxxvi., 1902. 



* Merletti, " Ricerohe e studl intorno ai poteri selettivi del' epitelio dei 

 villi ooriali," Rass. d'Ost. e. Ginec, 1903. 



"Bergell and Liepmaun, "Ueber die in der Placenta enthaltenen 

 Fermente," Miinch. med. Woch., 1905. 



' Savarfe, " ZurKeuntnis der Fermente der Placenta," ffo/meisier'sBcifragre, 

 vol. ix., 1907. 



' Bottazzi, "Placental Activity," Boll, delta R. Accad. med. Oenova, 

 vol. xviii. 



8 Charrin et Goupil, " Physiologie du Placenta," Oomp. Rend, de I'Acad. 

 des Sciences ; vol. cxli. , 1905 ; also vol. cxlii., 1906. 



' Ferroni, "L'eterolisi utero-placentare," Ann. di Ost. e Oinec, 1905. 



" V. Fiirth and Schneider, " Ueber tierische Tyrosinasen und ihre Bezie- 

 hungen zur Pigmentbildung," Hofmeister'a Beitriige, vol. i. 



2h 



