153 



CHAPTER IV. 



Of the Human Ovum. 



395. The human ovum, like that of other mammiferae, is com- 

 posed of the foetus and its appendages. 



ARTICLE I. 



Of the tdppcndages of the Foetus. 



396. The appendages of the foetus consist of the membranes, the 

 placenta and cord of the umbilical vesicle and allantois, and of the 

 liquor amnii. 



SECTION 1. 



Of the Membranes. 



The covering of the ovum is formed of three concentric layers, 

 the caduca, the chorion and the amnios. 



§• I. Of the Caduca or Connecting Membrane. 



397. The caducous membrane, membrana decidua, cellvlosa, sin- 

 uosa, spongiosa, common or pre-existing memhrane, connecting or 

 conjunctive membrane, epichorion, &c., is so evident at all periods 

 of gestation, that it must have been noticed by every physiologist 

 who has paid much attention to the examination of the human se- 

 cundines. Thus Aret.neus speaks of it pretty clearly under the 

 name of porous layer; Fabricius under that of membranous substance 

 of the placenta; G. Fallopius under the title of feshy substance, fyc; 

 Spigelius under that of the thick and fleshy portion of the chorion; 

 Ruysch under that of the velvety chorion; Rouhault, Littre, Hobo- 

 ken, under that of chorion; Haller under that of external ot fun- 



14* 



