No. 3.] UTERUS AND EMBRYO. 365 
spite of long searching for the phases representing their early 
history, I have failed to ascertain positively their origin. In the 
next section the question is recurred to. The monster cells vary 
in size: the smallest ones lienear the epithelium; the larger ones, 
for the most part, deeper down and even among the muscular 
fibres, but a few large cells lie next the surface. The body of 
the cell is evenly and coarsely granular and resembles the hya- 
line degenerated protoplasm of the epithelium ; its external out- 
line is distinct, well-rounded, and without processes; the nucleus, 
which often has a slight space around it, as if it had shrunk a 
little, has a clear regular outline, being apparently provided with 
a membrane; it is well colored by cochineal, and contains an 
indistinct network with imbedded granules of various sizes; in 
the smaller cells the nuclei have one or two granules much larger 
than the rest, and which may be spoken of as nucleoli; the size 
of the nucleus increases with that of the cell, and at the same 
time the granulation becomes coarser. 
The description of the placenta at ten and eleven days given 
by Masquelin and Swaen I have not been able to follow in all 
respects. Owing to their conclusion that the epithelium of the 
uterus gives rise to blood, they apply the term cavités hemato- 
blastiques to apparently all the cavities of the placenta except 
those of the maternal blood-vessels. I have compared their 
description very carefully with my own preparations: so far as 
this enables me to judge, their “cavités hamatoblastiques ” 
include the foetal blood-vessels, the vacuoles in the: degenerated 
glands, the spaces included within the epithelial U’s described in 
the next section, and which are supposed to be the tips of foetal 
villi, the multinucleate cells and perhaps also the sub-placenta. 
Why the multinucleate cells are included among the blood- 
forming organs the authors do not render clear. Their failure 
to recognize the variety of constituents in the glandular layer 
of the placenta must be ascribed to the want of the perfected 
methods at present at our disposal. With the means now at 
command there is no difficulty in obtaining preparations which 
show indisputably that the glands though degenerated persist 
intact, and do not give rise to blood cavities nor blood corpuscles 
as Masquelin and Swaen have erroneously believed. 
§ 8. Embryo at eleven to thirteen days. — As known already, 
the embryo is completely separated from the yolk sack, and the 
