No. 1.] ORIGIN OF HUMAN MONSTERS. 163 
system. The mesodermal tissues are characteristic and the 
form of the pharynx and lower jaw is recognizable. From 
this region the two branchial arteries pass into the cord, as 
the figures show. A single vein, however, passes from the 
cord directly into the center of the body and ends just below 
the lower jaw. There is no heart, liver, myotomes, nor lower 
end of the body, these being replaced by the cord. The ar- 
teries are empty and the vein is distended with blood. 
No. 54. 
Embryo, C. R., 11 mm. 
From Dr. McMorris, Belle Plaine, Iowa. 
The embryo alone was given me. It shows an atrophic 
head, but otherwise appears like a normal embryo of 4% 
weeks. 
In the sections it is seen that the central nervous system is 
solid with the exception of the mid-brain, whose ventricle still 
communicates with the exterior of the body through an open 
neuropore. The head is atrophic. The vertebra are well 
developed. The liver is large; the heart, other organs and 
ceelom are difficult to outline. 
No. 55. 
Ovum, 35 x 20 x 14 mm. 
From Dr. Watson, Baltimore. 
Last period January 18 to 22, abortion March 13, 1894. 
The specimen is a very solid fleshy mass, which contains a 
sharply defined spherical cavity, 15 mm. in diameter, with 
smooth walls. Absolutely no trace of an embryo found within 
this cavity. 
Blocks of the tissue were imbedded in celloidin and some 
sections were cut. The sharply defined cavity proved to be 
the ccelom, as its walls were formed by the chorion. The thick 
fleshy mass proved to be villi of the chorion, syncytium, blood, 
fibrin and pus. The walls of the chorion contain remnants of 
blood-vessels, are partly invaded by leucocytes and are fibrous. 
The main bulk of the villi and syncytium stains poorly and 
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