FCETAL NUTRITION: THE PLACENTA 



459 



is in contact with maternal blood or decidua. It increases from the 

 twelfth to the sixteenth day, then it decreases, and a week later 

 disappears altogether. In the maternal placenta fat first appears 

 in the decidual cells which are nearest the trophoblast. They show 





a 



^ 





FIG. 130. Iron granules in the placenta of the rabbit at the eighteenth day 

 of pregnancy. (Chipman.) 



a, Iron granules in mesoblast ; ft, iron granules in inultinucleate decidual 

 cells ; #, iron granules in ectodermal tubules. 



no sign of degeneration at this time, and they probably secrete the 

 fat globules. After increasing for a few days, it diminishes with 

 the atrophy of the decidual cells, and finally appears as fatty debris. 

 Fat is also present in the proliferating endothelium, and later in the 

 fibrin laminie of the uterine sinuses. 



In the new-born fcetus the main store of fat is contained in the 

 subcutaneous tissue. It is remarkable that it does not appear in 



