44 THE EMBEDDING OF THE OVUM. 



harbors the ovum and that this chamber nowhere in its interior 

 carries a lining of uterine epithelium. If this funnel was ac- 

 tually a gland orifice the good preservation of its cells would be 

 striking in contrast to the glandular openings still visible to the 

 sides of the ovum, since their epithelial cover consists almost 

 only of swollen, detached and liquified cells. 



The question suggests' itself, however, whether this funnel 

 shaped depression does not indicate the site where the ovum has 

 entered the mucosa. My ovum does not show any "Anlage" of 

 an embryo and therefore must be younger than that of Peters, 

 in which an amniotic cavity with an exocoelum is distinctly vis- 

 ible. The assumption may be justified that my ovum has just ac- 

 complished its nidation and is about to become sufficiently an- 

 chored to the ovular envelope by sending out trophoblastic pro- 

 cesses. The fact that this place at e. s. represents the only 

 visible connection, obviously leads to the question, whether or 

 not the ovum has possibly here entered the mucosa. This place 

 is certainly about to become obliterated by the encroachment of 

 decidual cells from both sides, but there is still a relation extant 

 between the interior and exterior. At a place within the blood 

 filled space of the ovular chamber lying closest to the depression 

 e. s. (in Fig. 6), an escape of red blood cells can be followed, one 

 sees how they collect at e. s. and from here permeate the fibrinous 

 cover. Thus one seems justified in assuming that also the fibrin- 

 ous cover has originated here, that it serves more or less as a 

 lid and that it is supplied with red blood cells until the envelope 

 completely surrounds the ovum. 



Before the structure and development of this fibrinous cover 

 is considered in detail, the process of embedding of the ovum, 

 and the ovular chamber must be considered. In all sections 

 (Figs. 14, 22 & 23, Plate VIII, XII & XIII) the decidua com- 

 pletely surrounding the ovum, shows the indentical histological 

 structure. Although varying in thickness at different places, 

 especially at the summit of the ovum and at both sides of the 

 mucosa elevation, the decidua everywhere consists of thin wavy 

 fibres containing larger and smaller decidua cells, numerous cap- 

 illaries and a large number of extravasated red blood cells. One 

 can therefore not say that the mucosa has reflected itself from 

 the two sides over the ovum, lying in its chamber, nor can as- 

 sert, that a scar can be seen on the summit of the ovular ele- 

 vation. 



Everything points rather to the fact, which has been proved 

 by Peters, that the ovum has burrowed its way into the mucosa, 

 in our specimen somewhat asymmetrically in a mucosa eleva- 



