THE DECIDUA 
15 
while their epithelium is desquamating and their lumen is occupied by 
extravasated blood. The whole membrane is thickly studded with leuco¬ 
cytes, mainly of the polymorphonuclear variety. All round the ovum 
the marginal lamella of the decidua is in a state of advanced coagulation 
necrosis, appearing as a hyaline, darkly-staining, and nearly nuclear-free 
zone dotted with polymorphonuclear leucocytes. Stained by Gram’s method 
this zone stands out as a deeply staining purple band, forming the wall of 
the implantation cavity. The plasmodium is not everywhere in contact 
with this layer. Here and there masses of it lie directly against the 
necrotic tissue, but round the rest of the circumference the two are 
separated by a space occupied by large mononuclear cells, the nature of 
which will be discussed below. The necrotic zone is broken up by the 
haemorrhage in the upper part of the section, and here and there, but in 
relatively few places, by masses of plasmodium, which are seen spreading 
outwards along the walls or into the lumina of blood-vessels. The mass 
of cells seen in Plate n, Fig. 2 and Plate in, Fig. 3, occupying the centre 
of the space between the cyto-trophoblast and the wall of the im¬ 
plantation cavity, corresponds to the layer of cells seen lying elsewhere 
immediately within the necrotic zone; the qells have here been dis¬ 
placed inwards by the haemorrhage which has broken into the implantation 
cavity. 
At either extremity of the implantation cavity an interesting condition 
of the glands is to be observed, from which it would appear that the 
gland walls resist the disintegration longer than the general tissue of the 
mucous membrane. The sections across each pole of the chamber show 
a gland in section with necrotic tissue and plasmodium on either side of it, 
as if the process of destruction were extending round the gland wall and 
isolating it. The implantation cavity is, as already stated, completely 
closed. There is no large aperture filled with blood clot such as is seen 
in Peters’ ovum, or Graf v. Spee’s youngest specimen. Over the blasto¬ 
cyst, but distinctly nearer one end of the implantation cavity, is a well 
marked pocket, T mm. in diameter, partially filled with what appears to 
be thrombus (Plate in, Fig. 3). Directly continuous with this, and reaching 
into the implantation cavity, is a spur-like projection of hyaline material 
