222 MALL. [VoL. XIX. 
ness, which frequently invades the mesoderm. The whole 
chorion is embedded in a large mass of mother’s blood. 
The most remarkable part of this specimen is found within 
the blood-vessels of the chorion. They are gorged with nu- 
cleated blood corpuscles filled with a pigment of the same 
color as that of the surrounding mother’s blood. It appears 
as if the syncytium, in destroying the mesoderm of the chorion 
and the mother’s blood, at the same time made it possible 
for the blood of the embryo to take up the blood pigment 
thus liberated. At any rate, the blood of a human embryo 
three weeks old contains no pigment, and the sections of this 
specimen permit of this interpretation. There is also a con- 
siderable quantity of mother’s blood within the ovum around 
the embryo, but as the specimen was opened before it was 
hardened and the corpuscles are all perfect, they need not be 
taken into consideration in the interpretation just given. 
No. 198. 
Ovum, 25 x 25 x 25 mm. 
Dr. Larsen, Chicago. 
The specimen came to me hardened in a mixture of bi- 
chromate of potash and formalin. The interior is filled with 
considerable reticular magma and large lumps of granular 
magma. Imbedded in.this there is a large cylindrical pedicle 
7 mm. long bent upon itself. Sections of this specimen show 
that pedicle to be the umbilical cord rounded off at its former 
juncture with the embryo. 
Fic. 198.—Pedicle within chorion. Enlarged 2 diameters. 
