210 MALL. [VoL. XIX. 
The ovum was cut into serial sections, but no trace of an 
embryo could be found. The sections show, however, that 
the chorion had been torn, but the edges of the tear were 
rounded and infiltrated with mesodermal cells. The main 
wall of the mesoderm and the villi in the neighborhood of the 
tear are fibrous and artophic. The rest of the villi are normal 
in appearance. 
No. 158. 
Tubal pregnancy; vesicle, 2 mm. in diameter. 
Professor W. T. Howard, Cleveland, Ohio. 
The specimen came to me imbedded in celloidin and 
mounted on blocks ready to cut. From each block sections 
were cut, three of which proved to be through the chorion. 
In one of these sections there was the remnant of an embryo 
within the chorion; from this piece I removed the celloidin 
and reimbedded it in paraffin and cut it into serial sections 50 
microns thick. 
The microscopical examination of the sections shows that 
the chorion is denuded entirely of its villi, being in apposition 
and apparently continuous with the wall of the uterine tube. 
Occasionally the line of separation is marked by a row of 
irregular cells, probably the remnants of the epithelial cover- 
ing of the chorion. The mesodermic portion of the chorion 
is somewhat fibrous, being smooth on its ccelom side and 
without an adhering amnion. The nodule within is shriveled 
and necrotic, only a few of its nuclei staining. It appears as 
a double sac, together measuring 2 mm. in diameter, with a 
clump of necrotic cells, appearing like those of the umbilical 
cord, between them. In none of the sections is the embryonic 
mass attached to the chorion. At one place, however, the 
cord-like structure runs into a long process toward the chorion 
with a blood-vessel (?) filled with blood in its center. 
My interpretation of the embryonic mass is that it is com- 
posed of amnion and umbilical vesicle of about equal size, 
shriveled and partly torn into pieces, but still held together by 
the remnants of the embryo and umbilical cord. 
