SECT. 12] GYCLOSES, PHOSPHORUS, SULPHUR 



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mammalian embryo, if we except, firstly, the researches which have 

 been done on the distribution of phosphorus compounds in the 

 maternal and foetal blood, and which will more conveniently be 

 reviewed in the Section on placental permeabihty; and, secondly, 

 the suggestion made by Parat that the meconium is not a waste 

 product, but a "veritable embryo trophe". Basing his conclusions 

 entirely on histological evidence, Parat decided that the methods 

 ordinarily used in histology "surprennent la cellule intestinale du 

 foetus humain de 3 a 8 mois en plein travail d'absorption". In other 

 words, the meconium was to be regarded as one of the means of 

 foetal nutrition, though Parat did not explain why the foetus should 

 secrete food for itself. Parat & Delaville subsequently made a few 

 fragmentary analyses of the organic and inorganic phosphorus in the 

 meconium at different stages of development, but the figures were 

 erratic. The subject merits fuller examination than it received from 

 these writers, and might well be joined to a chemical examination of 

 the "uterine milk" (seep. 1467) about which at present we know 

 nothing. 



The cholesterol metabolism of the mammalian embryo is again 

 quite uninvestigated, apart from the histochemical observations of 

 Yamaguchi. It is not possible to follow him in his far-reaching con- 

 clusions about the functions of cholesterol esters. A certain amount 

 of work has been done on the sterol content of the foetal and maternal 

 bloods, but this will be discussed under the heading of Placental 

 Permeability. The cholesterol content of the foetal suprarenals in 

 man has also been estimated: 



Man 



