386 GENERATION. 



oblique secondary trabecular processes. 1 The cliorionic villi, 

 according to the recent observations of Hennig, 2 contain 

 blood-vessels, which we have already described, surrounded 

 by a gelatinous, connective-tissue structure (Schleimgewebe\ 

 and are generally covered with a layer of nucleated cells of 

 pavement-epithelium. 



In parturition, the curling arteries and the veins on the 

 uterine surface of the placenta are torn off, and the placenta 

 then consists of the parts we have just described ; the torn 

 ends of these vessels attached to the uterus are closed by the 

 contractions of the surrounding muscular fibres ; and the 

 blood which is discharged is mainly derived from the placenta 

 itself. Thus the very contractions which expel the contents 

 of the uterus close the vessels and prevent loss of blood by 

 the mother. 



1 WINKLER, Zur Kentniss der men&chlichen Placenta. Archiv fur Grynaeko- 

 logie, Berlin, 1872, Bd. iv., S. 240. 



8 HENNIG, Studien uber den Bau der menschlichen Placenta, Leipzig, 1872, S. 

 19. 



