148 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
containing the mucin. In some sections these granules have attained considerable 
size, and, as they stain very deeply with all the basic dyes, they stand out in marked 
contrast to the rest ot the stroma. Whether these granules actually consist of the 
mucin secreted by the myxomatous cells is not certain, but it is quite reasonable to 
suppose that they do, since they possess all the physical characteristics of that 
substance. 
That part of the stroma immediately underlying the epithelial layer is the 
most cellular, the nuclei becoming more and more scarce as the centre of the vesicle 
is reached. 
In a vesicle about 2 mm. in diameter, the myxomatous tissue stretches right 
across, forming a very loose and delicate network, but in the large vesicles the central 
core has completely disappeared, the space being occupied by a thin watery fluid. 
One ot the most striking features, however, is the entire absence of blood 
vessels ; so far as can be made out, the entire foetal blood supply has been cut off*. 
This tact is ot great diagnostic value, especially in those cases where small portions 
of retained placenta are removed by the curette, and the diagnosis of the condition 
rests on microscopical evidence. That such retained masses do sometimes take on 
a myxomatous degeneration with proliferation ot the epithelium is beyond doubt, as 
two or three examples have come under my own observation. 
The epithelium overlying the degenerated stroma also shews changes which 
are ot great interest and importance. The most obvious of these is the marked pro- 
liferation of the cells, which in some specimens is so extreme as to suggest an adeno- 
matous condition. 
Both the syncytium and the zellschicht take part in the proliferation, some- 
times one being more in evidence than the other, but in most cases the former presents 
the most striking appearances. The protoplasm of the syncytium stains even more 
deeply than in a normal villus, and possess nuclei of large size, coarsely granular 
and ot very irregular shape. As in a normal villus, wherever the syncytium is in 
contact with the maternal blood, the nuclei shew the typical, elongated, and flat- 
tened appearance, and if the nuclei are two or even three layers deep, the inner- 
most are always seen to be more oval and round as they approach the zellschicht. 
But as we have already seen, both syncytium and zellschicht are remains of the 
foetal trophoblast, therefore the proliferation which forms so striking a feature of 
this condition is not to be regarded as due to the increase of two different kinds 
ot cells, but to one variety of epithelium which, according to its position on the 
villus, is seen to be flattened, plasmodial, oval, or cubical. 
This proliferation of the epithelium takes place principally on the external 
surface of the villus, where it forms large heaped-up masses of cells. These may 
be cut off and form islands which appear to lie free in the blood spaces, while 
others grow out into long finger-like processes which may branch and give off 
