5U THE PHYSIOLOGY OF REPRODUCTION 



cells of the body. When no change is made in the ordinary 

 diet, when no signs of dyspepsia are present and no glycosuria 

 exists, we are not justified in assuming a withdrawal of carbohy- 

 drates from the metabolism. Rather is it related to the aceton- 

 uria arising after chloroform and ether narcosis (Beesly) ^ or in 

 febrile conditions — that is, it is toxic in origin. It has, however, 

 still to be discovered whether the acetonuria of pregnancy is 

 associated, as the acetonuria of narcosis ^ and of fever (Regnard ^ 

 and Geppert *), with a diminished alkalinity of the blood. 



F. The Metabolism of Metals and Salts in Pregnancy 



Little is known regarding the metabohsm of the individual 

 metals and salts. The fixation of mineral elements is slight 

 at the beginning, but becomes active towards' the end of 

 pregnancy. From first to last, about a hundred grammes 

 are transferred from the mother to the human fcetus. With 

 a few exceptions, the mineral salts are approximately in the 

 same proportion throughout pregnancy. The exceptions are 

 sodium, potassium, and calcium, of which sodium decreases and 

 calcium increases with the replacement of cartilage by bone, 

 and potassium increases with the increased manufacture of 

 red blood corpuscles (Hugounenq ^). 



a. Iron. — Part at least of the iron for the foetus is derived 

 from the haemoglobin of the maternal organism.® In the 

 poly-cotyledonary placenta of Ruminants and the zonary placenta 

 of Carnivores, the disintegration of red blood corpuscles has 

 been demonstrated. There js less certainty regarding the actual 

 ingestion of the red cells by the syncytium of the discoid placenta, 



^ Beesly, " Post-An£esthetlc Acetonuria," Brit. Med. Joum., 1906. 



^ Beesly and Milne, unpublished paper. 



' Kegnard, Combustions respiratoires, 1879. 



* Geppert, "Die Gase des arteriellen Blutes im Fieber," Zeitschr. f. hlin. 

 Med., vol. ii. 



^ Hugounenq, "Eeoherches sur la statique des 61dments min^raux et 

 parfciculierement du fer ohez le foetus humain," Oomp. Rend. Sac. Biol., 

 llth series, vol. i., 1889. 



" It is doubtful whether haemoglobin is an " organised " protein, hence 

 its disintegration does not, as might be supposed, afford proof of the trans- 

 mission of maternal tissue protein to the foetus. 



