176 MALL. [VoL. XIX. 
Macroscopic as well as microscopic examination of the 
chorion shows that it has undergone extensive degeneration. 
Its walls are filled with large islands of blood and at points 
there is leucocytic infiltration, showing that an inflammatory 
process had also invaded it. Accompanying the inflammatory 
process the syncytial layer of cells has invaded the walls of 
the chorion, thus helping along its destruction. The meso- 
derm of the chorion has undergone fibrous degeneration and 
within its walls there are numerous cysts, some lined with flat 
epithelial cells and some with cylindrical. The amnion ap- 
pears normal and lines the entire ccelom. 
Fic. 81b.—Photograph of the embryo within the chorion. 
The embryo is somewhat atrophic. Its central nervous sys- 
tem is macerated and there is a marked cyst-like dilatation at 
the tip end of the spinal cord. All the tissues, including the 
cartilages, show more or less dissociation. The necrotic crest 
covering the top of the head gives all the appearance of an 
ulcer; the ectoderm is destroyed and the mesoderm covering 
the brain is greatly thickened and pigmented with round cell 
infiltration of the surrounding tissue. The marked dilatation 
in the cord encloses double cavities filled with a mucoid re- 
ticulum, much as in embryo No. 32. This tissue is similar in 
appearance to the normal notochord in amphibian embryos. 
