CHANGES IN THE MATERNAL ORGANISM 515 



thougli it has been described by Peters in an early human ovum.^ 

 But in all placentae yet investigated, iron-containing granules 

 have been observed in the trophoblast. The possible sources 

 are hsemoglobin, which is in part absorbed as such by the tropho- 

 blast in Man (Bonnet ^), nucleoprotein, and the reserve iron of 

 the mother. Nuclein is the only iron-containing constituent of 

 yolk of egg, and must serve for the manufacture of haemoglobin 

 in the developing chick. It is also known that in the adult 

 organism nucleoprotein is a better source of iron for haemoglobin 

 than any inorganic or other organic compound hitherto ad- 

 ministered by the mouth.^ Hence it is not difficult to conceive 

 that the same process may occur in the foetus. But whether it 

 is the food nucleoproteins or the organised nuclein bodies of 

 the maternal organism that are utihsed, is unknown.* With 

 regard to the reserve iron of the mother, it is stated by Charrin ^ 

 that the store in the spleen is reduced during pregnancy. 



In the foetus iron is required for the synthesis of haemoglobin 

 (see p. 480) and nucleoproteins.* Large amounts of iron are 

 also stored in the hver and other organs. According to Bunge's ' 

 law, this forms a reserve which is drawn on after birth to make 

 up for the deficiency- of the iron in the milk. Thus the hver of 

 a rabbit contains 18 mg. of iron per 100 grm. body-weight at 

 birth, and only 3'2 mg. twenty-four days later. 



According to Veit and Scholten,* the villi can dissolve intact 

 red cells of the circulating blood, just as the solution of erythro- 



' See Chap. X,, p. 479. ^ See Chap. X., p. 480. 



' V. Noorden, loc. cit., vol. i., p. 78. 



4 As the purine bases of the urine are stated to be decreased in pregnancy 

 (see p. 506), the maternal nucleins are probably not a source of iron for the 

 fcetns to any appreciable extent. 



' Charrin, " Physiologie pathologique de la grossesse," Comp. Bend. Soc. 

 de Biol., 1899. 



' The nucleoproteins of the foetal placenta in the sheep differ in their 

 chemical constitution from those of the maternal placenta. They are 

 probably synthesised in the ovum from lower complexes, in the same way 

 as the nucleoproteins of the chick embryo are built up though the egg 

 contains no purine bases. 



' Bunge, " Weitere Uutersuchungen iiber die Aufnahme des Eisens in 

 den Organismus des Sauglings," Zeiiachr. f. phys. Chem., vols. xvi. and 

 xvii., 1892-3. 



* Veit and Scholten, " Synzytiolyse and Haemolyse," Zeitachr. f. Qeburteh. 

 u. Qynak., vol. xlix. 



