DISCUSSION OF DATA 
From the foregoing description it will be apparent that the present 
ovum differs in certain important respects from any human ovum hitherto 
described. It is also in some of its features unlike any ovum with which 
we are acquainted among the lower mammals. 
The special characters of our specimen may be summarised as follows : 
(1) The blastocyst is completely enclosed in decidua except at one 
point, where there is a small gap closed by a mass of fibrin and leucocytes. 
The wide gap closed by the mushroom-like mass of fibrin and blood clot 
seen in Peters’ ovum is entirely absent. 
(2) The ovum lies, bathed in blood, in a relatively large implantation 
chamber with the walls of which it is not united. There is no interlocking 
or mixing of maternal and foetal tissues. The innermost layer of the decidua 
lining the cavity is in a state of advanced coagulation necrosis, and this, 
together with a certain amount of fibrinous deposit, forms a layer of dead 
material which is practically complete except at one or two points where 
blood-vessels have been opened up, and at one end where a haemorrhage 
has broken into the implantation chamber. 
(3) The wall of the blastocyst consists of an inner lamella (cyto- 
trophoblast or cell layer) composed of cells rather ill-defined from one 
another, and continuous externally with an extremely irregular formation 
which has definitely plasmodial characters (plasmodi-trophoblast). This 
forms a straggling reticulum, the meshes of which are filled with maternal 
blood (primitive blood lacunae). There is no protrusion of the cyto- 
trophoblast into the plasmodi-trophoblast strands. 
(4) The cavity of the blastocyst is filled by a delicate tissue having 
the characters of mesenchyme. There is no cleavage of this early mesoblast 
