No. 1.] ORIGIN OF HUMAN MONSTERS. 89 
of the chorion are in apposition throughout most of the spect- 
men, and at points they. have grown together. There is no 
amnion, and on this account I place the beginning of this mole 
back to the first month of pregnancy. The extensive ramifica- 
tion of the folds of the chorion shows that it must have con- 
tinued to grow throughout the nine months of its existence, 
this being made possible by the nourishment brought to it 
by the fresh blood in its interior. Islands of syncytial cells 
are located upon the chorionic wall throughout the specimen. 
The syncytium shows active growth and its cells stain well 
at numerous points where they come in contact with fresh 
blood. All the syncytial masses, distant from the fresh blood, 
are necrotic, which is undoubtedly due to the lack of nutrition. 
Nests of leucocytes with fragmented nuclei are scattered 
throughout the specimen. The walls of the chorion are not 
invaded by the syncytium. 
In a number of the specimens enumerated above it was 
noted that the villi are oedematous and hyaline, a condition 
which might easily end in hydatid degeneration of the villi, 
forming hydatiform mole. In a specimen which contains an 
embryo 17 mm. long (No. 357) many of the villi are quite 
large and have undergone hydatiform degeneration. Another 
specimen (No. 70) contains a small ccelom which sends radi- 
ating cavities into the walls of the hypertrophied villi. There 
is no amnion. Ina second very large mole (No. 323) most 
of the villi are about 5 mm. in diameter, and some of thetn 
four times as long. They are very irregular in form, the 
larger ones containing cavities, some measuring I5 x 10 mm., 
giving all the characteristics of the ccelom. Between the villi 
there are numerous masses of necrotic syncytium, some blood 
and leucocytes, which invade the mesoderm of some of them. 
